| suitability of protuberances on the third eyelids of sheep as a biopsy site for lymphoid follicles. | | 2000 | 11128078 |
| immunohistochemical detection of prp in the medulla oblongata of sheep: the spectrum of staining in normal and scrapie-affected sheep. | sections of the medulla oblongata from the brains of sheep were examined for prion protein (prp) by immunohistochemistry. on the basis of the morphology and neuroanatomical distribution of the deposits, distinct disease-associated patterns of prp deposition were identified in scrapie-affected sheep, suggesting at least four distinct phenotypes of scrapie. in addition, clearly defined patterns of prp deposition, readily distinguished from the disease-associated prp deposits, were identified in so ... | 2001 | 11200410 |
| [still a small problem with the mad cow disease? creutzfeldt-jakob disease and other prion diseases: current status]. | this review is based on recent published research on the bse/cjd/vcjd problem mainly from uk, germany and france. the situation in sweden seems to be fortunate for several reasons. the use of meat and bonemeal as animal fodder was forbidden in this country 13 years ago. sweden has not had any sheep with scrapie for many years. no animals with bse have so far been found in our country. the incidence of sporadic cjd in this country followed retrospectively from 1985 to 1996 and prospectively from ... | 2001 | 11213704 |
| application of prionics western blotting procedure to screen for bse in cattle regularly slaughtered at swiss abattoirs. | disease-specific prp (prp(sc)) is at least part of the infectious particle (prion) causing bovine spongiform encephalopathy (bse) or scrapie in sheep. digestion with protease allows a distinction between normal prp (prp(c)) and prp(sc) i.e. prp(c) is completely digested while prp(sc) is cleaved at the n-terminus leading to a fragment of reduced molecular weight (prp 27-30). detection of this fragment by western blotting has been described more than a decade ago for rodent prp. we have now optimi ... | 2000 | 11214922 |
| characterization of bse and scrapie strains/isolates. | following the bse epidemic in cattle and the emergence of a variant form of creutzfeldt-jakob disease in humans, the question was raised whether bse has been transmitted to small ruminants by the inadvertent feeding of infectious meat and bone meal. such infections could easily be concealed in countries where scrapie is endemic. to address this issue by immuno-chemically analyzing the prp(sc) fragments, we have developed two lines of research. firstly we have focused on the development of criter ... | 2000 | 11214925 |
| temporary depletion of complement component c3 or genetic deficiency of c1q significantly delays onset of scrapie. | following peripheral exposure to transmissible spongiform encephalopathies (tses), infectivity usually accumulates in lymphoid tissues before neuroinvasion. the host prion protein (prpc) is critical for tse agent replication and accumulates as an abnormal, detergent insoluble, relatively proteinase-resistant isoform (prpsc) in diseased tissues. early prpsc accumulation takes place on follicular dendritic cells (fdcs) within germinal centers in lymphoid tissues of patients with variant creutzfeld ... | 2001 | 11283677 |
| a lysosomal storage disease of romney sheep that resembles human type 3 gm1 gangliosidosis. | during a large neuropathological survey of clinically normal sheep for evidence of scrapie, three adult romney ewes from the same farm were found to have populations of distended neurons containing granular eosinophilic storage material. the affected neurons were confined to the striatum. the granules had the tinctorial properties of glycolipid and the ultrastructural appearance of spherical bodies containing concentric membranous whorls. the bodies resembled those of gm1 gangliosidosis. the res ... | 2001 | 11307621 |
| protease-resistant prion protein in brain and lymphoid organs of sheep within a naturally scrapie-infected flock. | the hallmark of transmissible spongiform encephalopathies (tse), such as scrapie in sheep, is the accumulation in tissues of an insoluble and protease resistant form (prpres) of the cellular prion protein. in this study, we evaluated whether the diversity in both the clinical pattern and the prp genotypes of scrapied sheep from the same flock was connected with different levels and/or glycoform patterns of the prpres in the brain and lymphoid organs of the animals. whereas the prpres levels in s ... | 2000 | 10839972 |
| amyloidogenic unfolding intermediates differentiate sheep prion protein variants. | sheep is a unique example among mammalian species to present a strong correlation between genotype and prion disease susceptibility phenotype. indeed a well-defined set of prp polymorphisms at positions 136, 154 and 171 (sheep numbering) govern scrapie susceptibility, ranging from very high susceptibility for v136-r154-q171 variant (vrq) to resistance for a136-r154-r171 variant (arr). to get better insight into the molecular mechanisms of scrapie susceptibility/resistance, the unfolding pathways ... | 2002 | 12270715 |
| usda authorizes funding for scrapie eradication. | | 2000 | 10844956 |
| neurophysin in the brain and pituitary gland of normal and scrapie-affected sheep--i. its localization in the hypothalamus and neurohypophysis with particular reference to a new hypothalamic neurosecretory pathway to the median eminence. | by use of an immunofluorescence histochemical technique with a cross-species reactive antiserum to porcine neurophysin-ii the precise localization of neurophysin in the pituitary gland and the hypothalamic area of the brain of the sheep has been determined. neurophysin was confined to neurosecretory pathways originating from the supraoptic and paraventricular hypothalamic nuclei. the major pathway terminates in the neurohypophysis but in addition a second neurophysin-containing pathway proceeds ... | 1976 | 11370513 |
| primary culture of neural precursors from the ovine central nervous system (cns). | the present study demonstrates that bipotential neural precursors isolated from an early developmental stage of the sheep embryo nervous system can be maintained in vitro in an undifferentiated state for a long period. these precursors multiplied under the action of epidermal growth factor and basic fibroblast growth factor and formed free-floating aggregates of nestin-immunoreactive cells, called neurospheres. these precursors can undergo predominantly neural or glial differentiation according ... | 2001 | 11389950 |
| markedly increased susceptibility to natural sheep scrapie of transgenic mice expressing ovine prp. | the susceptibility of sheep to scrapie is known to involve, as a major determinant, the nature of the prion protein (prp) allele, with the vrq allele conferring the highest susceptibility to the disease. transgenic mice expressing in their brains three different ovine prp(vrq)-encoding transgenes under an endogenous prp-deficient genetic background were established. nine transgenic (tgov) lines were selected and challenged with two scrapie field isolates derived from vrq-homozygous affected shee ... | 2001 | 11390599 |
| spiroplasma sp. 16s rdna in creutzfeldt-jakob disease and scrapie as shown by pcr and dna sequence analysis. | the pathogenesis of the transmissible spongiform encephalopathies (tse), which include creutzfeldt-jakob disease (cjd) in humans and scrapie in sheep, remains an enigma. in this paper we present evidence for the association of spiroplasma sp., a wall-less prokaryote, with tse. we have shown pcr amplification of spiroplasma 16s rdna in tse-infected brain tissues (13 of 13 cjd cases and 5 of 9 scrapie cases) and not in control brains (0 of 50). direct sequencing of the amplified pcr products has c ... | 2001 | 11398837 |
| scrapie strains maintain biological phenotypes on propagation in a cell line in culture. | bovine spongiform encephalopathy (bse) and its human equivalent, variant creutzfeldt-jakob disease (vcjd), are caused by the same strain of infectious agent, which is similar to, but distinct from, >20 strains of their sheep scrapie homologue. a better understanding of the molecular strain determinants could be obtained from cells in monoculture than from whole animal studies where different cell targeting is commonly a strain-related feature. although a few cell types can be infected with diffe ... | 2001 | 11432823 |
| review blames bse outbreak on calf feed. | | 2001 | 11484009 |
| a survey of more than 11 years of neurologic diseases of ruminants with special reference to transmissible spongiform encephalopathies (tses) in greece. | the first cases of scrapie were detected in greece in a flock of sheep in october 1986. all the animals of the affected flock and all sheep in two flocks that were in contact were killed and buried. a systematic investigation of all available cases with signs indicating a neurological disease started in sheep and goats in late 1986, as well as in cattle in 1989. the investigation was based on clinical examination, necropsy or macroscopical examination of the brain and viscera, and histological e ... | 2000 | 10861199 |
| surveillance for scrapie. | | 2000 | 10888003 |
| molecular analysis of irish sheep scrapie cases. | | 2000 | 10900052 |
| clinical signs and diagnosis of scrapie in italy: a comparative study in sheep and goats. | this article reports the clinical signs of scrapie occurring in sheep-goat flocks in italy. the research, carried out on over 500 goats and 550 sheep, yielded an interesting clinical picture, especially of goat scrapie. the affected animals, aged between 2 and 8 years, showed neurological signs that could be classified into three categories: changes in mental status, abnormalities of movement and changes in sensation. some general clinical signs were also observed. the clinical suspicion was con ... | 2001 | 11515309 |
| changing a single amino acid in the n-terminus of murine prp alters tse incubation time across three species barriers. | the prp gene of the host exerts a major influence over the outcome of transmissible spongiform encephalopathy (tse) disease, but the mechanism by which this is achieved is not understood. we have introduced a specific mutation into the endogenous murine prp gene using gene targeting to produce transgenic mice with a single amino acid alteration (proline to leucine) at amino acid position 101 in their prp protein (p101l). the effect of this alteration on incubation time, targeting and prp(sc) for ... | 2001 | 11566872 |
| [prion diseases in animals]. | | 2001 | 11977754 |
| the rationale for ridding u.s. of scrapie. | | 2002 | 11991401 |
| bse: a consequence of cattle feeding with glycated molecules host-unknown? | although there is much evidence supporting a prion contribution in the pathogenesis of transmissible spongiform encephalopathies, a novel point of view as to the induction of the diseases can be proposed. it is hypothesized that neurodegenerative diseases, such as scrapie in sheep and goats and bovine spongiform encephalopathy in cattle (bse), originate from the consumption of glycated proteins contained in their feed. these components are obtained during a high-temperature glycation process. | 2002 | 12027519 |
| antiaggregating antibody raised against human prp 106-126 recognizes pathological and normal isoforms of the whole prion protein. | antibodies to the prion protein (prp) have been critical to the neuropathological and biochemical characterization of prp-related degenerative diseases in humans and animals. although prp is highly conserved evolutionarily, there is some sequence divergence among species; as a consequence, anti-prp antibodies have a wide spectrum of reactivity when challenged with prp from diverse species. we have produced an antibody [monoclonal antibody (mab) 2-40] raised against a synthetic peptide correspond ... | 2001 | 12043842 |
| influence of the prion protein gene, prnp, on scrapie susceptibility in sheep. | natural scrapie in sheep occurs through a complex interplay between host genetic elements and various strains of the infectious scrapie agent. scrapie-related polymorphisms in the coding region of the prion protein (prp) gene, prnp, have been studied in a number of breeds. the disease-promoting v136 allele, and the susceptibility-reducing r171 allele, have proved to be most important. however, variation in the coding region of prnp cannot alone explain the diverse patterns of scrapie susceptibil ... | 2002 | 12064254 |
| discriminant value of blood and urinary corticoids for the diagnosis of scrapie in live sheep. | the mean (sd) concentration of plasma 20beta-dihydrocortisol in 126 scrapie-affected sheep was 5-5 (7.0) ng/ml compared with 1.1 (0.7) ng/ml in 52 healthy sheep. the mean (sd) concentration of creatinine in the urine of 93 scrapie-affected sheep was 2.43 (1.56) microg/ml compared with 0.94 (0.86) pg/ml in 49 healthy sheep and 1.10 (0-95) pg/ml in 25 sheep with other diseases. these discriminant analyses carried out on healthy and scrapie-affected sheep showed that plasma 20beta-dihydrocortisol a ... | 2002 | 12074236 |
| active surveillance for scrapie by third eyelid biopsy and genetic susceptibility testing of flocks of sheep in wyoming. | control of scrapie, an ovine transmissible spongiform encephalopathy or prion disorder, has been hampered by the lack of conventional antemortem diagnostic tests. currently, scrapie is diagnosed by postmortem examination of the brain and lymphoid tissues for prp(sc), the protein marker for this group of disorders. for live, asymptomatic sheep, diagnosis using tonsil or third-eyelid lymphoid tissue biopsy and prp(sc) assay has been described. to evaluate the feasibility and efficacy of third-eyel ... | 2002 | 12204945 |
| myopathy in sheep; its relationship to scrapie and to dermatomyositis and muscular dystrophy. | | 1956 | 13368509 |
| vacuolated neurones in sheep affected with scrapie. | | 1957 | 13407753 |
| [consequences of bse/tse for the clinical diagnostic in cattle and sheep]. | the first case of bovine spongiform encephalopathy (bse) in germany induced a profound irritation not only of the consumers but also of the farmers and the veterinarians in germany. the following bse-crisis accelerated the structural changes in beef and dairy industries. the analysis of the detected bse-cases of the last years in germany and switzerland shows that the sensitivity of bse-tests is much higher in clinically preselected bse-suspected cases compared to bse-tests in normal slaughter c ... | 2002 | 12224461 |
| prp(sc) accumulation in placentas of ewes exposed to natural scrapie: influence of foetal prp genotype and effect on ewe-to-lamb transmission. | placentas from scrapie-affected ewes are known to be infectious. nevertheless, placenta infectivity in such ewes is not systematic. maternal transmission to lambs is highly suspected but contamination of the foetus in utero has not been demonstrated. using ewes from a naturally scrapie-infected flock, it was demonstrated that abnormal prion protein (prp(sc)) accumulation in the placenta (i) is controlled by polymorphisms at codons 136, 154 and 171 of the foetal prp gene and (ii) is restricted ma ... | 2002 | 12237445 |
| sheep/human comparative map in a chromosome region involved in scrapie incubation time shows multiple breakpoints between human chromosomes 14 and 15 and sheep chromosomes 7 and 18. | a chromosome region involved in scrapie incubation time was identified on sheep chromosome 18 (oar18). since oar18 (and oar7) share conserved chromosome segments with human chromosomes hsa14 and hsa15, a dense map of type i markers was constructed by fish mapping of bacterial artificial chromosomes containing genes located on these human chromosomes. in this study, we used the complete human sequence information (gene positions in megabases, mb) to locate approximately one gene every 2 mb on hsa ... | 2002 | 12296519 |
| phenotyping of protein-prion (prpsc)-accumulating cells in lymphoid and neural tissues of naturally scrapie-affected sheep by double-labeling immunohistochemistry. | transmissible spongiform encephalopathies are fatal neurodegenerative diseases characterized by amyloid deposition of protein-prion (prpsc), the pathogenic isoform of the host cellular protein prpc, in the immune and central nervous systems. in the absence of definitive data on the nature of the infectious agent, prpsc immunohistochemistry (ihc) constitutes one of the main methodologies for pathogenesis studies of these diseases. in situ prpsc immunolabeling requires formalin fixation and paraff ... | 2002 | 12364569 |
| the bse-susceptible proportion of uk sheep. | | 2002 | 12418532 |
| the transmissible spongiform encephalopathies: disease risks for north america. | transmissible spongiform encephalopathies exotic to north america (bse and associated diseases) are unlikely to be introduced or to persist should they be introduced into the united states [2]. domestic tses (scrapie, cwd, and tme) seem to be relatively restricted in their host range, and none of these diseases is known to naturally cause disease in cattle. it is important that surveillance for tses continues, however, particularly in cattle because of the extreme consequences to the livestock i ... | 2002 | 12442578 |
| occurrence and distribution of infection-specific prp in tissues of clinical scrapie cases and cull sheep from scrapie-affected farms in shetland. | the prion protein (prp) genotypes of all cull sheep originating from four scrapie-affected farms in shetland in 1998-1999 were determined and a representative sample of the different genotypes was selected for necropsy. samples of brain and selected viscera were removed from 159 such sheep aged 2-11 years. these samples were examined immunohistochemically and by western blotting for infection-specific forms of prp. none of the sheep bearing the following genotypes showed any evidence of prp accu ... | 2002 | 12443734 |
| the shifting biology of prions. | transmissible spongiform encephalopathies (tses), or prion diseases, are rare fatal neurodegenerative diseases of humans and animals. although some tses, like scrapie in sheep, have been known to exist for centuries, bovine spongiform encephalopathy (bse) was recognized only 15 years ago. new variant creutzfeldt-jakob disease (nvcjd) of humans is probably caused by consumption of bse-infected materials. the nature of the infectious agent is not fully elucidated, but substantial evidence suggests ... | 2001 | 11690621 |
| characterization of thermodynamic diversity between transmissible spongiform encephalopathy agent strains and its theoretical implications. | some transmissible spongiform encephalopathy (tse) (or "prion") strains, notably those derived from bovine spongiform encephalopathy, are highly resistant to total inactivation by heat. when three tse strains derived from sheep with scrapie were heated, little inactivation took place at low temperatures, but at higher temperatures, considerable inactivation occurred. the temperature at which substantial inactivation first occurred varied according to tse strain, and it was calculated to be 70 de ... | 2002 | 11792707 |
| validation of a luminescence immunoassay for the detection of prp(sc) in brain homogenate. | a luminescence immunoassay (lia) was developed for the diagnosis of bovine spongiform encephalopathy (bse) in brain tissue using two different monoclonal antibodies for capture and detection of the protease-resistant fragment of the pathological prion protein (prp27-30). prp27-30 currently represents the most reliable marker for the infectious particle (denominated prion) causing transmissible spongiform encephalopathies (tses). internal and official validation studies of this assay are describe ... | 2002 | 11849686 |
| risk management of the transmissible spongiform encephalopathies in north america. | as north american free trade agreement partners, canada, the united states of america (usa) and mexico apply independent but harmonised transmissible spongiform encephalopathy (tse) risk management strategies in observance of office international des epizooties guidelines. the divergence between bovine spongiform encephalopathy (bse) risk management approaches in north american and europe reflects comparatively reduced external and internal bse risks in north america. the external quarantine and ... | 2003 | 12793780 |
| the potential for transmissible spongiform encephalopathies in non-ruminant livestock and fish. | pigs and poultry in the united kingdom have undeniably been exposed to the bovine spongiform encephalopathy (bse) agent. they consumed the same ruminant protein that gave rise to the bse epidemic in cattle, but there has been no evidence of an epidemic in these species. experimental investigations have shown pigs to be susceptible to infection by multiple parenteral challenge, but resistant to oral exposure with bse-infected cattle brain. current but incomplete evidence suggests that they are al ... | 2003 | 12793786 |
| 'complex' prp genotypes identified by the national scrapie plan. | | 2003 | 12833938 |
| analysis of polymorphic microsatellites within the bovine and ovine prion protein (prnp) genes. | twenty-four microsatellite sites with at least three repeats were found in the bovine prion protein gene (prnp) and 23 in the ovine prnp gene. eight microsatellite sites were polymorphic in cattle and six in sheep with up to 10 alleles per site. in many cases allelic dna fragments had variants in microsatellite sites and in flanking regions. distances between microsatellite sites in eight genes from cattle and sheep occurred on average every 0.9 kb. the numerous polymorphic microsatellite sites ... | 2003 | 12873216 |
| identification of a novel lysine-171 allele in the ovine prion protein (prnp ) gene. | | 2003 | 12873221 |
| scrapie; a study in ohio. | | 1954 | 13129159 |
| degeneration of the cerebellar and hypothalamoneurohypophysial systems in sheep with scrapie; and its relationship to human system degenerations. | | 1964 | 14152208 |
| transmission by contact of scrapie in mice. | | 1964 | 14198336 |
| scrapie: a transmissible and hereditary disease of sheep. | | 1962 | 14484073 |
| introduction to the transmissible spongiform encephalopathies or prion diseases. | sheep scrapie has been known for at least 200 years and was described as a transmissible disease over 100 years ago. since then, three groups of transmissible spongiform encephalopathies or tse diseases have been identified in humans including familial, infectious and sporadic types. the discovery of the prion protein (prp) in the 1980s greatly accelerated knowledge of the biology and pathogenesis of tse diseases as this protein was found to play a critical role in disease susceptibility and the ... | 2003 | 14522845 |
| bovine spongiform encephalopathy (bse) and its epidemiology. | since the recognition of bse in 1986, over 180,000 cattle in the uk have developed the disease and 1-3 million are likely to have been infected with the bse agent, most of which were slaughtered for human consumption before developing signs of the disease. the origin of the first case of bse is unknown, but the epidemic was caused by the recycling of processed waste parts of cattle, some of which were infected with the bse agent, to other cattle in feed. control measures have resulted in the con ... | 2003 | 14522859 |
| experimental transmission of abnormal prion protein (prpsc) in the small intestinal epithelial cells of neonatal mice. | using an immunohistochemical method, we attempted to detect the transmission of abnormal prion protein (prpsc) to the enterocytes of the small intestine of neonatal mice by oral exposure with sheep brain affected by scrapie. five 1-day-old neonatal mice were exposed by oral inoculation to the homogenized brain of a scrapie-affected sheep. in the small intestine of all mice 1 hour after inoculation, immunoreactivity with antinormal prion protein (prpc) antibody was seen in the cytoplasm of villus ... | 2003 | 14608031 |
| epidemiological implications of the susceptibility to bse of putatively resistant sheep. | the experimental infection of sheep with bovine spongiform encephalopathy (bse) by the oral route and the likelihood that sheep were fed bse-infected meat and bone meal has led to extensive speculation as to whether or not sheep are naturally infected with bse. in response, the uk government has initiated the national scrapie plan (nsp), an ambitious pound 120 million per year project to create a bse- and scrapie-resistant national sheep flock, by selectively breeding for a genotype of sheep bel ... | 2003 | 14645932 |
| is mad cow disease caused by a bacteria? | transmissible spongioform enchephalopathies (tse's), include bovine spongiform encephalopathy (also called bse or "mad cow disease"), creutzfeldt-jakob disease (cjd) in humans, and scrapie in sheep. they remain a mystery, their cause hotly debated. but between 1994 and 1996, 12 people in england came down with cjd, the human form of mad cow, and all had eaten beef from suspect cows. current mad cow diagnosis lies solely in the detection of late appearing "prions", an acronym for hypothesized, ge ... | 2004 | 15325025 |
| cultured peripheral neuroglial cells are highly permissive to sheep prion infection. | transmissible spongiform encephalopathies arise as a consequence of infection of the central nervous system (cns) by prions. spreading of the infectious agent through the peripheral nervous system (pns) may represent a crucial step toward cns neuroinvasion, but the modalities of this process have yet to be clarified. here we provide further evidence that pns glial cells are likely targets for infection by prions. glial cell clones originating from dorsal root ganglia of transgenic mice expressin ... | 2004 | 14671128 |
| [the prion protein]. | transmissible spongiform encephalopathies form a group of fatal neurodegenerative disorders represented principally by creutzfeldt-jakob disease in humans, and by scrapie and bovine spongiform encephalopathy in animals. also called prion diseases, these disorders have the property of being infectious, sporadic or genetic in origin. although the nature of the responsible agent of these diseases is uncertain, it is clear that a protein called prpsc has a central role in their pathology. prpsc is a ... | 2002 | 12645301 |
| [present-day knowledge of bse and creutzfeldt-jakob disease]. | | 2003 | 12649789 |
| searching for bse in sheep: interpreting the results so far. | | 2003 | 12650473 |
| cd21-positive follicular dendritic cells: a possible source of prpsc in lymph node macrophages of scrapie-infected sheep. | natural sheep scrapie is a prion disease characterized by the accumulation of prp(sc) in brain and lymphoid tissues. previous studies suggested that lymph node macrophages and follicular dendritic cells (fdc) accumulate prp(sc). in this study, lymph nodes were analyzed for the presence of prp(sc) and macrophage or fdc markers using dual immunohistochemistry. a monoclonal antibody (mab) to the c-terminus of prp reacted with cd172a+ macrophages and cd21+ fdc processes in secondary follicles. howev ... | 2003 | 12651600 |
| susceptibility of transgenic mice expressing chimeric sheep, bovine and human prp genes to sheep scrapie. | the use of transgenic (tg) mice expressing chimeric sheep/mouse (sh/mo) prion protein (prp) and chimeric bovine/mouse (bo/mo) prp genes was evaluated as a sheep scrapie model. we also investigated the potential for the transmission of sheep scrapie to a human/mouse (hu/mo) prp tg mouse line. the sh/mo prp and bo/mo prp tg prnp(+/+) or prnp(0/0) mouse lines were inoculated intracerebrally with brain homogenates from three sheep with natural scrapie (ku, y5 or s2). incubation periods were slightly ... | 2003 | 12679564 |
| validation of monoclonal antibody f99/97.6.1 for immunohistochemical staining of brain and tonsil in mule deer (odocoileus hemionus) with chronic wasting disease. | a new monoclonal antibody (mab), f99/97.6.1, that has been used to demonstrate scrapie-associated prion protein prp(sc) in brain and lymphoid tissues of domestic sheep with scrapie was used in an immunohistochemistry assay for diagnosis of chronic wasting disease (cwd) in mule deer (odocoileus hemionus). the mab f99/97.6.1 immunohistochemistry assay was evaluated in brain and tonsil tissue from 100 mule deer that had spongiform encephalopathy compatible with cwd and from 1,050 mule deer outside ... | 2002 | 12680636 |
| scrapie and chronic wasting disease. | scrapie and cwd share many features. there are marked similarities in the clinical presentations, the lesions, and the pathogenesis of these diseases, and some similarities in the epidemiology. extrapolation from the scrapie model of tse disease to cwd--which occurs in three different species, and should not be considered to be uniform in their response--may be erroneous, however. such differences may influence diagnostics (e.g., the amount and distribution of prpc in these different species), p ... | 2003 | 12733429 |
| [cytopathological changes in human and animal brain in prion diseases]. | the study of brain histological sections of humans and animals afflicted by prion diseases has shown that neuronal vacuolization began in and intensely spread from the distal portions of dendrites. two types of neuronal cell body death were demonstrated, including cytolysis and pyknosis, the latter being usually associated with dendrite vacuolization. the involvement of major glial types in the pathogenesis of prion diseases was established, which argues against the concept of astrocytosis in fa ... | 2003 | 12741105 |
| frequencies of prion protein (prp) genotypes and distribution of ages in 15 scrapie-affected flocks in great britain. | the frequencies of prion protein (prp) genotypes were investigated in 15 scrapie-affected flocks in great britain. the flocks were heterogeneous in the frequencies of different genotypes and alleles, and in their age distributions. the median flock frequency of animals with vrq-containing genotypes was 21 per cent (range 2 to 82 per cent, mean 25 per cent). the vrq-containing and other non-arr genotypes made up 11 to 82 per cent of a flock (median 46 per cent, mean 48 per cent). in comparison wi ... | 2004 | 14725423 |
| scrapie in sheep. | | 1950 | 14814231 |
| allelic variants of ovine prion protein gene (prnp) in oklahoma sheep. | 1,144 sheep belonging to 21 breeds and known crosses were sequence analyzed for polymorphisms in the ovine prnp gene. genotype and allele frequencies of polymorphisms in prnp known to confer resistance to scrapie, a fatal neurodegenerative disease of sheep, are reported. known polymorphisms at codons 136 (a/v), 154 (h/r) and 171 (q/r/h/k) were identified. the frequency of the 171r allele known to confer resistance to type c scrapie was 53.8% and the frequency of the 136a allele known to influenc ... | 2003 | 14970685 |
| comparative molecular analysis of the abnormal prion protein in field scrapie cases and experimental bovine spongiform encephalopathy in sheep by use of western blotting and immunohistochemical methods. | since the appearance of bovine spongiform encephalopathy (bse) in cattle and its linkage with the human variant of creutzfeldt-jakob disease, the possible spread of this agent to sheep flocks has been of concern as a potential new source of contamination. molecular analysis of the protease cleavage of the abnormal prion protein (prp), by western blotting (prp(res)) or by immunohistochemical methods (prp(d)), has shown some potential to distinguish bse and scrapie in sheep. using a newly develope ... | 2004 | 15016886 |
| breeding german sheep for resistance to scrapie. | susceptibility to clinical scrapie is associated with polymorphisms in the prion protein (prp) gene. the arr allele reduces susceptibility to clinical disease caused by all known strains of the transmissible spongiform encephalopathy (tse) agents. for the economically important german breeds of sheep the prp allele frequencies are well known, but this paper presents representative genotyping results for 1526 sheep from two smaller milk sheep breeds and 2446 sheep from 14 mostly indigenous land s ... | 2004 | 15029963 |
| evaluation of rapid tests for the diagnosis of transmissible spongiform encephalopathies in sheep and goats. | in accordance with eu regulation 999/2001, rapid tests already adopted for bovine spongiform encephalopathy (bse; prionics check western, platelia-bse and enfer tse) are to be applied in all european countries to a sub-population of over 18-month-old slaughtered or dead sheep and goats to improve scrapie surveillance and to determine the possible presence of bse in sheep; however, the three tests have thus far been evaluated only for bse and no official data are available about their performance ... | 2004 | 15067554 |
| detection of polymorphisms in the prion protein gene in the belgian sheep population: some preliminary data. | the development of clinical signs of tse/scrapie in sheep has been linked to polymorphisms in the prion protein (prnp) gene. the most important polymorphisms appear to be at codons 136, 154, and 171. the objective of this study was to investigate the polymorphisms at these codons in the belgian sheep population, including clinical healthy animals, healthy animals at the slaughterhouse and animals in tse/scrapie positive farms (including a nor98 farm). | 2004 | 15072136 |
| current concepts and controversies in prion immunopathology. | scrapie in sheep and new variant creutzfeldt-jakob disease in humans are typically initiated by extracerebral exposure to prions. both exhibit early prion accumulation in sites of the peripheral lymphoreticular system, such as splenic or lymph nodal germinal centers. in germinal centers, follicular dendritic cells (fdcs), whose development and maintenance depend on lymphotoxin and tumor necrosis factor signaling, are believed to be the main cell type for efficient prion replication in the periph ... | 2004 | 15126687 |
| diagnosis of preclinical scrapie in samples of rectal mucosa. | | 2005 | 15980141 |
| prpsc accumulation in myocytes from sheep incubating natural scrapie. | because variant creutzfeldt-jakob disease (vcjd) in humans probably results from consumption of products contaminated with tissue from animals with bovine spongiform encephalopathy, whether infectious prion protein is present in ruminant muscles is a crucial question. here we show that experimentally and naturally scrapie-affected sheep accumulate the prion protein prp(sc) in a myocyte subset. in naturally infected sheep, prp(sc) is detectable in muscle several months before clinical disease ons ... | 2004 | 15156203 |
| two creutzfeldt-jakob disease agents reproduce prion protein-independent identities in cell cultures. | human creutzfeldt-jakob disease (cjd) and similar neurodegenerative diseases such as sheep scrapie are caused by a variety of related infectious agents. they are associated with abnormal host prion protein (prp), which is assessed by limited proteolysis to yield resistant prp bands (prp-res). although prp-res has been posited as the infectious agent, purified prp-res itself is not infectious. to establish the independence of cjd agent characteristics from those of prp-res, two different mouse-pa ... | 2004 | 15161970 |
| breeding programmes for tse resistance in british sheep. i. assessing the impact on prion protein (prp) genotype frequencies. | from april 2005, member states of the european union were required to implement a compulsory breeding programme for resistance to transmissible spongiform encephalopathies (tses) in sheep as part of measures to eradicate tses from national flocks. in this paper, we assessed the impact of four different breeding strategies on prion protein (prp) genotype frequencies using a mathematical model which describes in detail gene flow in the british sheep flock. these strategies ranged from the minimum ... | 2006 | 16169614 |
| prion infection of epithelial rov cells is a polarized event. | during prion infections, the cellular glycosylphosphatidylinositol-anchored glycoprotein prp is converted into a conformational isoform. this abnormal conformer is thought to recruit and convert the normal cellular prp into a likeness of itself and is proposed to be the infectious agent. we investigated the distribution of the prp protein on the surface of rov cells, an epithelial cell line highly permissive to prion multiplication, and we found that prp is primarily expressed on the apical side ... | 2004 | 15194791 |
| cells release prions in association with exosomes. | prion diseases are infectious neurodegenerative disorders linked to the accumulation in the central nervous system of the abnormally folded prion protein (prp) scrapie (prpsc), which is thought to be the infectious agent. once present, prpsc catalyzes the conversion of naturally occurring cellular prp (prpc) to prpsc. prion infection is usually initiated in peripheral organs, but the mechanisms involved in infectious spread to the brain are unclear. we found that both prpc and prpsc were activel ... | 2004 | 15210972 |
| prion protein allele a136 h154q171 is associated with high susceptibility to scrapie in purebred and crossbred german merinoland sheep. | prion protein (prp) genotypes were determined in eight sheep that have been tested positive for atypical scrapie from purebred or crossbred merinoland sheep flocks in germany and compared with the prp genotypes of their flock mates. two restriction fragment length polymorphism (rflp) analyses were developed to determine all prnp haplotypes occurring by variations at codons 136, 154 and 171. at least one copy of the a(136) h(154) q(171) (ahq) allele was found in all scrapie-positive sheep while t ... | 2004 | 15290381 |
| associations between the prion protein genotype and performance traits of meat breeds of sheep. | the prion protein (prp) genotypes of four german meat breeds of sheep were examined in relation to their scores for muscle mass, conformation, wool quality, daily liveweight gain and ultrasonic measurements of the depth of back muscle and back fat. the dataset included 912 genotyped german texel sheep among 10,383 recorded sheep, 474 genotyped suffolk sheep among 4079 recorded sheep, 271 genotyped german white-headed mutton sheep among 3393 recorded sheep, and 99 genotyped german black-headed mu ... | 2004 | 15338706 |
| the role of prp in health and disease. | transmissible spongiform encephalopathies (tses) such as scrapie in sheep, bovine spongiform encephalopathy (bse) in cattle or creutzfeldt-jacob disease (cjd) and gerstmann-sträussler-scheinker syndrome (gss) in humans, are caused by an infectious agent designated prion. the "protein only" hypothesis states that the prion consists partly or entirely of a conformational isoform of the normal host protein prpc and that the abnormal conformer, when introduced into the organism, causes the conversio ... | 2004 | 15354865 |
| molecular approaches to mechanisms of prion diseases. | prion diseases such as scrapie in sheep, bovine spongiform encephalopathy in cattle, creutzfeldt-jakob disease, gerstmann-sträussler-scheinker disease and fatal familial insomnia in man are neurodegenerative disorders. in humans, the diseases can be sporadic, inherited, or acquired by infection. the underlying pathogenic event in prion diseases is a conformational modification of the cellular isoform prion protein (prp(c)) to the pathogenic isoform (prp(sc)) that accumulates in the central nervo ... | 2004 | 15449458 |
| characterization of a complex formed between human plasminogen and recombinant sheep prion: pressure and thermal sensitivity of complex formation. | scrapie is thought to be caused by one or more conformations of a proteinacious particle called a prion. the infectious form(s) is referred to as the scrapie form of the prion protein (prpsc) whereas a benign form, the cellular conformer, is referred to as prpc. the cellular conformation of the sheep prion protein formed a 1:1 complex with human plasminogen. the complex precipitated at 0 degrees c (ksp = 17* 10(-12) m2). this precipitation reaction was sensitive to both temperature and pressure. ... | 2004 | 15529749 |
| alterations of somatotropic function in prion disease in sheep. | this study aimed at investigating the possible linkage between natural scrapie and alterations of the somatotropic axis. scrapie-affected ewes exhibited 2-fold higher mean gh concentrations during both autumn and spring. gh pulse frequencies were higher in scrapie-affected ewes than in control animals (mean+/-s.e.m. number of pulses/24 h: 10.4+/-0.9 and 7.6+/-0.9 for scrapie-affected and control ewes respectively) suggesting the involvement of central mechanisms. gh secretion induced by administ ... | 2004 | 15531730 |
| prion protein gene polymorphisms in healthy and scrapie-affected sheep in greece. | a total of 216 local crossbred sheep from 16 scrapie-affected greek flocks and 210 purebred sheep of the milk breeds chios and karagouniko from healthy flocks were analysed for scrapie-linked polymorphisms in the prion protein (prp) gene. of the 216 sheep in this case-control study, 96 sheep were clinical cases, 25 subclinical cases (asymptomatic at the moment of euthanasia but positive by histopathology and/or elisa detecting proteinase-resistant prp) and 95 healthy controls (negative by all ev ... | 2004 | 14769911 |
| [comments on present-day spread and epidemiology of bse and prion diseases]. | prion diseases of animals and man are neurological diseases with amyloidal deposition of the respective proteins. as to prion disease, the cellular prion protein is in its abnormal isoform(s) an essential component of prion protein aggregates found in affected tissue. in contrast to all neurodegenerative diseases like morbus alzheimer or huntington's disease, prion diseases are transmissible. therefore, prion diseases were designated transmissible spongiform encephalopathies (tse). the diseases ... | 2004 | 14770333 |
| phenotype of disease-associated prp accumulation in the brain of bovine spongiform encephalopathy experimentally infected sheep. | in view of the established link between bovine spongiform encephalopathy (bse) and variant creutzfeldt-jakob disease and of the susceptibility of sheep to experimental bse, the detection of potential cases of naturally occurring bse in sheep has become of great importance. in this study, the immunohistochemical (ihc) phenotype of disease-associated prion protein (prp(d)) accumulation has been determined in the brain of 64 sheep, of various breeds and prp genotypes, that had developed neurologica ... | 2005 | 15722546 |
| a modelling framework to describe the spread of scrapie between sheep flocks in great britain. | my aim was to develop a stochastic, spatial model describing the spread of scrapie between sheep flocks in great britain; i wanted a model, which could subsequently be used to assess the efficacy of different control strategies. the structure of the model reflects the demography of the british sheep flock, including a description of the contact structure between flocks. the dynamics of scrapie were incorporated through two probabilities associated with each flock: of acquiring infection and of e ... | 2005 | 15737428 |
| detection of prion protein using a capillary electrophoresis-based competitive immunoassay with laser-induced fluorescence detection and cyclodextrin-aided separation. | the development of capillary electrophoresis (ce)-based competitive immunoassay for prion protein (prp) using carboxymethyl beta-cyclodextrin (cm-beta-cd) as a buffer additive is described here. the assay was based on the competitive binding of prp and a fluorescein-labeled peptide from the prion protein with a limiting amount of specific antibody. the amount of both free and fluorescein-labeled peptide bound to antibody (immunocomplex) were determined by ce with laser-induced fluorescence detec ... | 2005 | 15815999 |
| transmission barriers for bovine, ovine, and human prions in transgenic mice. | transgenic (tg) mice expressing full-length bovine prion protein (boprp) serially propagate bovine spongiform encephalopathy (bse) prions without posing a transmission barrier. these mice also posed no transmission barrier for suffolk sheep scrapie prions, suggesting that cattle may be highly susceptible to some sheep scrapie strains. tg(boprp) mice were also found to be susceptible to prions from humans with variant creutzfeldt-jakob disease (cjd); on second passage in tg(boprp) mice, the incub ... | 2005 | 15827140 |
| postmortem diagnosis of preclinical and clinical scrapie in sheep by the detection of disease-associated prp in their rectal mucosa. | samples of tissue from the central nervous system (cns), the lymphoreticular system (lrs) and the rectal mucosa of a large number of scrapie-exposed sheep, with and without signs of clinical disease, were examined immunohistochemically for evidence of disease-associated prion protein (prp(d)). the rectal mucosa has received almost no attention so far in scrapie diagnosis, despite its abundant rectoanal mucosa-associated lymphoid tissue, and its accessibility. the scrapie-confirmed cases included ... | 2006 | 16531580 |
| expression of prpc on cellular components of sheep blood. | prp(c), a glycosylphosphatidylinositol-linked glycoprotein, plays a central role in the pathogenesis of transmissible spongiform encephalopathies (tses), undergoing a conformational alteration to the disease-associated isoform, commonly designated prp(sc). prp(c) is expressed in many tissues other than the nervous system, although its precise function(s) remains unclear. it has previously been demonstrated that tses can be transmitted by blood transfusion in sheep. the aim of this work was to id ... | 2005 | 15831971 |
| using genotype probabilities in survival analysis: a scrapie case. | the objective was to evaluate the potential use of genotype probabilities to handle records of non-genotyped animals in the context of survival analysis. to do so, the risks associated with the prp genotype and other transmission factors in relation to clinical scrapie were estimated. data from 4049 romanov sheep affected by natural scrapie were analyzed using survival analysis techniques. the original data set included 1310 animals with missing genotypes; five of those had uncensored records. d ... | 2005 | 15943919 |
| scrapie in ancient china? | | 2005 | 16081716 |
| the first canadian indigenous case of bovine spongiform encephalopathy (bse) has molecular characteristics for prion protein that are similar to those of bse in the united kingdom but differ from those of chronic wasting disease in captive elk and deer. | brain tissue from a case of bovine spongiform encephalopathy (bse) from alberta was subjected to a western immunoblotting technique to ascertain the molecular profile of any disease-specific, abnormal prion protein, that is, prion protein that is protease-resistant (prp(res)). this technique can discriminate between isolates from bse, ovine scrapie, and sheep experimentally infected with bse. isolates of brain tissue from the bse case in alberta, 3 farmed elk with chronic wasting disease (cwd) f ... | 2004 | 15532881 |
| postal questionnaire survey of scrapie in sheep flocks in ireland. | | 2004 | 15537145 |
| possible role of region 152-156 in the structural duality of a peptide fragment from sheep prion protein. | the conformational conversion of the nonpathogenic "cellular" prion isoform into a pathogenic "scrapie" protease-resistant isoform is a fundamental event in the onset of transmissible spongiform encephalopathies (tse). during this pathogenic conversion, helix h1 and its two flanking loops of the normal prion protein are thought to undergo a conformational transition into a beta-like structure. a peptide spanning helix h1 and beta-strand s2 (residues 142-166 in human numbering) was studied by cir ... | 2004 | 15537751 |
| the quantification of prion gene expression in sheep using real-time rt-pcr. | determination of the transcription level of cellular prion protein (prp(c)) is essential for understanding its poorly explained role in organisms. scrapie in sheep is the prototype of all prion diseases. however, the expression of prion protein (prp) mrna in sheep has not been quantified in great detail. herein we report on measurement of sheep prp mrna using absolute quantitative real-time reverse transcription and polymerase chain reaction (rt-pcr). total rna was isolated from seven different ... | 2006 | 16991008 |
| advances in screening test development for transmissible spongiform encephalopathies. | the blood of patients with transmissible spongiform encephalopathy or prion disease can no longer be considered free of infectivity. there have been two recent reports of highly probable transfusion-associated iatrogenic variant creutzfeldt-jakob disease infections, and there is supporting experimental evidence of scrapie transmission by the transfusion of blood from sheep with naturally occurring disease. in the absence of a preclinical diagnostic test for transmissible spongiform encephalopath ... | 2004 | 15566331 |
| biology of prpsc accumulation in two natural scrapie-infected sheep flocks. | sheep scrapie is a prion disease that requires interaction of exogenous prions with host prion protein (prp) supporting prion formation. disease is associated with deposition of a host-generated conformational variant of prp, prpsc, in a variety of tissues, including brain, resulting in fatal spongiform encephalopathy. efficiency of prpsc formation is determined by polymorphisms in the prp-coding sequence. this article adds to previous data of natural sheep scrapie, concentrating on the effect o ... | 2004 | 15586562 |
| bse inoculation to prion diseases-resistant sheep reveals tricky silent carriers. | the possible transmission of bovine spongiform encephalopathy (bse) agent to sheep contributed to select genetically sheep considered as resistant to prion diseases i.e., with prp arr/arr genotype. here, we report the infection of two prp arr/arr genotype sheep using the cattle bse agent inoculated by peripheral routes. disease-associated prion protein (prp(d)) was detected in the brain for one case (at 2191 days post-infection (dpi)) and only in the nervous enteric system for the other one (at ... | 2006 | 17049491 |