Publications

TitleAbstractYear(sorted descending)
Filter
PMID
Filter
a heparin purification process removes spiked transmissible spongiform encephalopathy agent.in 2000, bovine heparin was withdrawn from the us market for fear of contamination with bovine spongiform encephalopathy (bse) agent, the cause of variant creutzfeldt-jakob disease in humans. thus, us heparin is currently sourced only from pig intestines. availability of alternative sources of crude heparin, a life-saving drug, would benefit public health. bovine heparin is an obvious option, but bse clearance by the bovine heparin manufacturing process should be evaluated. to this end, using ha ...201728116677
the brain no levels and nos activities ascended in the early and middle stages and descended in the terminal stage in scrapie-infected animal models.the infections of prion agents may cause progressive and fatal neurodegenerative diseases in humans and a serial of animal species. previous studies have proposed that the levels of nitric oxide (no) and nitric oxide synthase (nos) in the brains of some neurodegeneration diseases changed, while s-nitrosylation (sno) of many brain proteins altered in prion diseases. to elucidate the potential changes of brain no levels during prion infection, the no levels and nos activities in the brain tissues ...201726887380
prion protein and genetic susceptibility to diseases caused by its misfolding.early genetic studies on scrapie, an infectious neurodegenerative disease of sheep that was adapted to mice, provided evidence in support of the hypothesis that the agent was a slow virus with a nucleic acid genome independent of the host. particularly compelling support for an independent genome came from the existence of strains of scrapie agent, some of which were true breeding, while others appeared to mutate under selective pressure. kuru, a neurodegenerative disease in the remote highlands ...201728838658
reduction of nf-κb (p65) in scrapie-infected cultured cells and in the brains of scrapie-infected rodents.transcription factor nf-κb functions as a pleiotropic regulator of target genes controlling physiological function as well as pathological processes of many different diseases, including some neurodegenerative diseases. however, the role of nf-κb in the pathogenesis of prion disease remains ambiguous. in this study, the status of nf-κb (p65) in a prion-infected cell line smb-s15 was first evaluated. significantly lower levels of p65 and the phosphorylated form of p65 (p-p65) were detected in smb ...201728783945
overexpression of plk3 mediates the degradation of abnormal prion proteins dependent on chaperone-mediated autophagy.polo-like kinase 3 (plk3) is the main cause of cell cycle reentry-related neuronal apoptosis which has been implicated in the pathogenesis of prion diseases. previous work also showed the regulatory activity of exogenous plk3 on the degradation of prp (prion protein) mutants and pathogenic prp(sc); however, the precise mechanisms remain unknown. in this study, we identified that the overexpression of plk3-mediated degradation of prp mutant and prp(sc) was repressed by lysosome rather than by pro ...201627344333
the priority position paper: protecting europe's food chain from prions.bovine spongiform encephalopathy (bse) created a global european crisis in the 1980s and 90s, with very serious health and economic implications. classical bse now appears to be under control, to a great extent as a result of a global research effort that identified the sources of prions in meat and bone meal (mbm) and developed new animal-testing tools that guided policy. priority ( www.prionpriority.eu ) was a european union (eu) framework program 7 (fp7)-funded project through which 21 europe ...201627220820
oral inoculation of neonatal suffolk sheep with the agent of classical scrapie results in prp(sc) accumulation in sheep with the prnp arq/arq but not the arq/arr genotype.scrapie is a transmissible spongiform encephalopathy that can be transmitted amongst susceptible sheep. the prion protein gene (prnp) profoundly influences the susceptibility of sheep to the scrapie agent. this study reports the failure to detect prp(sc) in nervous or lymphoid tissues of suffolk sheep of the prnp arq/arr genotype after oral inoculation with a u.s. scrapie isolate. lambs were inoculated within the first 24 h of birth with 1 ml of a 10% (wt./vol.) brain homogenate derived from a c ...201627033930
evidence of scrapie transmission to sheep via goat milk.previous studies confirmed that classical scrapie can be transmitted via milk in sheep. the current study aimed to investigate whether scrapie can also be transmitted via goat milk using in vivo (new-born lambs fed milk from scrapie-affected goats due to the unavailability of goat kids from guaranteed scrapie-free herds) and in vitro methods (serial protein misfolding cyclic amplification [spmca] on milk samples).201627640200
fbxw7-induced mtor degradation forces autophagy to counteract persistent prion infection.autophagy is an important protein degradation pathway and a part of the innate immune system that is activated in the brain tissue during animal and human prion diseases. however, the possible mechanism by which prion infection triggers autophagy and the significance of activated autophagy on prion accumulation remain unknown. here, we demonstrated that autophagic flux was enhanced in the persistent prion-infected cell line, smb-s15. knockdown of atg5 and the presence of three autophagic inhibit ...201625579381
(1)h nmr brain metabonomics of scrapie exposed sheep.while neurochemical metabolite modifications, determined by different techniques, have been diffusely reported in human and mice brains affected by transmissible spongiform encephalopathies (tses), this aspect has been little studied in the natural animal hosts with the same pathological conditions so far. herein, we investigated, by high resolution (1)h nmr spectroscopy and multivariate statistical data analysis, the brain metabolite profile of sheep exposed to a scrapie agent in a naturally af ...201525959287
lack of prion accumulation in lymphoid tissues of prnp arq/arr sheep intracranially inoculated with the agent of scrapie.sheep scrapie is a transmissible spongiform encephalopathy that can be transmitted horizontally. the prion protein gene (prnp) profoundly influences the susceptibility of sheep to the scrapie agent and the tissue levels and distribution of prpsc in affected sheep. the purpose of this study was to compare the survival time and prpsc tissue distribution in sheep with highly resistant and highly susceptible prnp genotypes after intracranial inoculation of the agent of scrapie. five sheep each of ge ...201425233232
remarkable reductions of paks in the brain tissues of scrapie-infected rodent possibly linked closely with neuron loss.prion diseases are irreversible progressive neurodegenerative diseases characterized in the brain by prp(sc) deposits, neuronal degeneration, gliosis and by cognitive, behavioral and physical impairments, leading to severe incapacity and inevitable death. proteins of the p21-activated kinase (pak) family are noted for roles in gene transcription, cytoskeletal dynamics, cell cycle progression and survival signaling. in the present study, we aimed to identify the potential roles of paks during pri ...201424870058
apparent reduction of adam10 in scrapie-infected cultured cells and in the brains of scrapie-infected rodents.it has been described that a disintegrin and metalloproteinase (adam10) may involve in the physiopathology of prion diseases, but the direct molecular basis still remains unsolved. in this study, we confirmed that adam10 was able to cleave recombinant human prion protein in vitro. using immunoprecipitation tests (ip) and immunofluorescent assays (ifa), reliable molecular interaction between the native cellular form of prp (prp(c)) and adam10 was observed not only in various cultured neuronal cel ...201424771043
disruption of glycosylation enhances ubiquitin-mediated proteasomal degradation of shadoo in scrapie-infected rodents and cultured cells.shadoo (sho) is an n-glycosylated glycophosphatidylinositol-anchored protein that is expressed in the brain and exhibits neuroprotective properties. recently, research has shown that a reduction of sho levels may reflect the presence of prpsc in the brain. however, the possible mechanism by which prion infection triggers down-regulation of sho remains unclear. in the present study, western blot and immunohistochemical assays revealed that sho, especially glycosylated sho, declined markedly in th ...201424390475
interaction between 14-3-3β and prp influences the dimerization of 14-3-3 and fibrillization of prp106-126.proteins of the 14-3-3 family are universal participate in multiple cellular processes. however, their exact role in the pathogenesis of prion diseases remains unclear. in this study, we proposed that human prp was able to form molecular complex with 14-3-3β. the domains responsible for the interactions between prp and 14-3-3β were mapped at the segments of amino acid (aa) residues 106-126 within prp and aa 1-38 within 14-3-3β. homology modeling revealed that the key aa residues for molecular in ...201424269782
infection of prions and treatment of prp106-126 alter the endogenous status of protein 14-3-3 and trigger the mitochondrial apoptosis possibly via activating bax pathway.the 14-3-3 proteins are a family of highly homologous and ubiquitously expressed isoforms that are involved in a wide variety of physiological processes. 14-3-3 have showed actively molecular interaction with prp and positive 14-3-3 is frequently observed in the cerebrospinal fluid (csf) samples of the patients with sporadic creutzfeldt-jakob disease (cjd). however, the alterations of 14-3-3 in the brain tissues of patients with prion diseases remain little addressed. to address the possible cha ...201424135906
abnormally upregulated αb-crystallin was highly coincidental with the astrogliosis in the brains of scrapie-infected hamsters and human patients with prion diseases.αb-crystallin is a member of the small heat shock protein family constitutively presenting in brains at a relatively low level. to address the alteration of αb-crystallin in prion disease, the αb-crystallin levels in the brains of scrapie agent 263 k-infected hamsters were analyzed. the levels of αb-crystallin were remarkably increased in the brains of 263 k-infected hamsters, showing a time-dependent manner along with incubation time. immunohistochemical (ihc) and immunofluorescent (ifa) assays ...201323832485
prp octarepeats region determined the interaction with caveolin-1 and phosphorylation of caveolin-1 and fyn.caveolin-1 is one of the major constituents of caveolae. both cav-1 and prp are plasma membrane proteins, which show active capacities for molecular interactions with many other proteins or agents, including themselves. using yeast two-hybrid system and immunoprecipitation, we reconfirmed the molecular interaction between human cav-1 and prp. with co-immunoprecipitation tests, prp(c)-cav-1 and prp(sc)-cav-1 complexes were identified in the brain homogenates of normal and scrapie agent 263k-infec ...201323283514
in vitro prion protein conversion suggests risk of bighorn sheep (ovis canadensis) to transmissible spongiform encephalopathies.transmissible spongiform encephalopathies (tses) affect both domestic sheep (scrapie) and captive and free-ranging cervids (chronic wasting disease; cwd). the geographical range of bighorn sheep (ovis canadensis; bhs) overlaps with states or provinces that have contained scrapie-positive sheep or goats and areas with present epizootics of cwd in cervids. no tses have been documented in bhs, but the susceptibility of this species to tses remains unknown.201323938169
a bayesian framework to assess the potential for controlling classical scrapie in sheep flocks using a live diagnostic test.current strategies to control classical scrapie remove animals at risk of scrapie rather than those known to be infected with the scrapie agent. advances in diagnostic tests, however, suggest that a more targeted approach involving the application of a rapid live test may be feasible in future. here we consider the use of two diagnostic tests: recto-anal mucosa-associated lymphatic tissue (ramalt) biopsies; and a blood-based assay. to assess their impact we developed a stochastic age- and prion ...201324021519
three-dimensional reconstruction of the pharyngeal tonsil innervation pattern in sheep.the pharyngeal tonsil has recently been identified as a new participant in airborne contamination by the ovine scrapie agent. in the context of scrapie pathogenesis, we conducted a three-dimensional reconstruction of the innervation pattern in the lymphoid compartments of this tonsil. this model confirmed that very few nerve fibres penetrated the lymphoid follicles and suggested that the nerve fibre distribution in the interfollicular and subepithelial areas is more suitable with neuro-invasion ...201323932773
evaluation of a combinatorial approach to prion inactivation using an oxidizing agent, sds, and proteinase k.prions demonstrate an unusual resistance to methods effective at inactivating conventional microorganisms. this has resulted in a very tangible and difficult infection control challenge to the medical and veterinary communities, as well as animal agriculture and related industries. currently accepted practices of harsh chemical treatments such as prolonged exposure to sodium hydroxide or sodium hypochlorite, or autoclaving are not suitable in many situations. less caustic and more readily applic ...201323886483
prion protein: structural features and related toxicity.transmissible spongiform encephalopathies, or prion diseases, is a group of infectious neurodegenerative disorders. the conformational conversion from cellular form (prp(c)) to disease-causing isoform (prp(sc)) is considered to be the most important and remarkable event in these diseases, while accumulation of prp(sc) is thought to be the main reason for cell death, inflammation and spongiform degeneration observed in infected individuals. although these rare but unique neurodegenerative disorde ...201323615535
abnormal activation of microglia accompanied with disrupted cx3cr1/cx3cl1 pathway in the brains of the hamsters infected with scrapie agent 263k.microglial cells are resident mononuclear phagocytes of the central nervous system (cns). active proliferation of microglia in the brain has been identified in neurodegenerative disorders, including some kinds of prion disease. however, the detailed regional distribution between microglia and prp(sc) deposition has not been presented, and investigation of fractalkine signaling which is involved in the regulation of activation of microglia in prion disease is not well documented. in this study, t ...201323526370
role of cd40 in prion disease and the immune response to recombinant prp.the cd40 receptor-cd40 ligand (cd40-cd40l) interaction has been shown to affect both immune and non-immune cells and is implicated in diverse activities including immunoglobulin class switching (igm to igg), atherosclerosis, chronic inflammation and alzheimer's disease pathogenesis. a number of groups have studied the role of cd40 in prion disease, however, the results are conflicting presumably due to the use of different scrapie agent-host strain combinations and routes of infection. in the cu ...201323419881
exposure of rml scrapie agent to a sodium percarbonate-based product and sodium dodecyl sulfate renders prpsc protease sensitive but does not eliminate infectivity.prions, the causative agents of the transmissible spongiform encephalopathies, are notoriously difficult to inactivate. current decontamination recommendations by the world health organization include prolonged exposure to 1 n sodium hydroxide or > 20,000 ppm sodium hypochlorite, or autoclaving. for decontamination of large stainless steel surfaces and equipment as in abattoirs, for example, these methods are harsh or unsuitable. the current study was designed to evaluate the effectiveness of a ...201323311930
removal of tse agent from plasma products manufactured in the united kingdom.the outbreak of vcjd in the uk leads to concern regarding the potential for human-to-human transmission of this agent. plasma-derived products such as albumin, immunoglobulin and coagulation factors were manufactured by bpl from uk plasma up until 1999 when a switch to us plasma was made. in the current study, the capacity of various manufacturing processes that were in use both prior to and after this time to remove the tse agent was tested.201323170907
acetone precipitation of the scrapie agent results in successful recovery of prp(sc) but decreased infectivity.bioassay is considered the most sensitive method for evaluating prion inactivation procedures. because prions are resistant to methods effective at inactivating conventional microorganisms, prion inactivation research has focused on relatively harsh alternatives, such as concentrated sodium hypochlorite or sodium hydroxide. often, bioassay for residual infectivity in these studies requires dilution or biochemical alteration of the treated sample in order to maintain subject health and survival. ...201222519670
heat shock protein 70 selectively mediates the degradation of cytosolic prps and restores the cytosolic prp-induced cytotoxicity via a molecular interaction.although the aggregation of prpsc is thought to be crucial for the neuropathology of prion diseases, there is evidence in cultured cells and transgenic mice that neuronal death can be triggered by the accumulation of cytosolic prps, leading to the hypothesis that the accumulation of prps in the cytosol of neurons may be a primary neurotoxic culprit. hsp70, a molecular chaperone involved in protein folding/refolding and degradation in the cytoplasm, has a protective effect in some models of neuro ...201223216755
historical overview of prion diseases: a view from afar.the transmissible spongiform encephalopathies (tses), or prion diseases, are a group of neurodegenerative disorders which include kuru, creutzfeldt-jakob disease (cjd), gerstmann-sträussler-scheinker (gss) syndrome, and fatal familial insomnia in men, natural scrapie in sheep, goats and mufflons, transmissible mink encephalopathy in ranch-reared mink, chronic wasting disease of mule deer and elk, bovine spongiform encephalopathy or "mad cow disease" and its analogues in several exotic species of ...201222505359
proper calibration of ultrasonic power enabled the quantitative analysis of the ultrasonication-induced amyloid formation process.to elucidate the mechanisms of ultrasonication on the amyloid fibril formation, we quantitatively determined the ultrasonic power using both calorimetry and potassium iodide (ki) oxidation, and under the properly calibrated ultrasonic power, we investigated the ultasonication-induced amyloid formation process of the mouse prion protein (mprp(23-231)). these methods revealed that the ultrasonic power in our system ranged from 0.3 to 2.7 w but entirely dependent on the positions of the ultrasonic ...201222095682
the oral secretion of infectious scrapie prions occurs in preclinical sheep with a range of prnp genotypes.preclinical sheep with the highly scrapie-susceptible vrq/vrq prnp genotype secrete prions from the oral cavity. in order to further understand the significance of orally available prions, buccal swabs were taken from sheep with a range of prnp genotypes and analyzed by serial protein misfolding cyclic amplification (spmca). prions were detected in buccal swabs from scrapie-exposed sheep of genotypes linked to high (vrq/vrq and arq/vrq) and low (arr/vrq and ahq/vrq) lymphoreticular system involv ...201222013047
Frequency distribution of PRNP polymorphisms in the Pakistani population.Prion diseases are neurodegenerative conditions caused by misfolding of a normal host-encoded prion protein (PrP(C)) into pathogenic scrapie prion protein (PrP(Sc)). In human prion diseases, the M129V prion protein polymorphism is known to confer susceptibility to the disease, determines PrP(Sc) conformation and alters clinicopathological phenotypes. To date, all clinicopathologically confirmed cases of a variant form of Cruetzfeldt-Jacob disease (vCJD) have been 129MM homozygotes. There is also ...201222062631
the effects of host age on the transport of complement-bound complexes to the spleen and the pathogenesis of intravenous scrapie infection.infections with variant creutzfeldt-jakob disease (vcjd) have almost exclusively occurred in young patients, but the reasons for this age distribution are uncertain. our data suggest that the pathogenesis of many peripherally acquired transmissible spongiform encephalopathy (tse) agents is less efficient in aged individuals. four vcjd cases linked to transfusion of vcjd-contaminated blood or blood products have been described. three cases occurred in elderly patients, implying that intravenous e ...201222031932
prion protein polymerisation triggered by manganese-generated prion protein seeds.prion diseases are neurodegenerative diseases that can be transmitted between individuals. the exact cause of these diseases remains unknown. however, one of the key events associates with the disease is the aggregation of a cellular protein, the prion protein. the mechanism of this is still unclear. however, it is likely that the aggregation is trigged by a seeding mechanism in which an oligomer of the prion protein is able to catalyse polymerisation of further prion protein into larger aggrega ...201222007749
soil-mediated prion transmission: is local soil-type a key determinant of prion disease incidence?prion diseases, including chronic wasting disease (cwd) and scrapie, can be transmitted via indirect environmental routes. animals habitually ingest soil, and results from laboratory experiments demonstrate prions can bind to a wide range of soils and soil minerals, retain the ability to replicate, and remain infectious, indicating soil could serve as a reservoir for natural prion transmission and a potential prion exposure route for humans. preliminary epidemiological modeling suggests soil tex ...201222265680
assessing prion infectivity of human urine in sporadic creutzfeldt-jakob disease.prion diseases are neurodegenerative conditions associated with a misfolded and infectious protein, scrapie prion protein (prp(sc)). prp(sc) propagate prion diseases within and between species and thus pose risks to public health. prion infectivity or prp(sc) presence has been demonstrated in urine of experimentally infected animals, but there are no recent studies of urine from patients with creutzfeldt-jakob disease (cjd). we performed bioassays in transgenic mice expressing human prp to asses ...201222260924
selection of distinct strain phenotypes in mice infected by ovine natural scrapie isolates similar to ch1641 experimental scrapie.abstract: a few cases of transmissible spongiform encephalopathies in sheep have been described in france in which the protease-resistant prion protein (prp) exhibited some features in western blot of experimental bovine spongiform encephalopathy in sheep. their molecular characteristics were indistinguishable from those produced in the ch1641 experimental scrapie isolate. four of these ch1641-like isolates were inoculated intracerebrally into wild-type c57bl/6 mice. in striking contrast to prev ...201222249459
time course of prion seeding activity in cerebrospinal fluid of scrapie-infected hamsters after intratongue and intracerebral inoculations.to assess prospects for early diagnosis of prion disease based on prion seeding activity in cerebrospinal fluid (csf), we measured the activity over time in scrapie-infected hamsters by real-time quaking-induced conversion (rt-quic). after intracerebral inoculation, activity appeared in csf within 1 day and plateaued weeks before the onset of clinical signs. however, after intratongue inoculation, activity first appeared in csf with the onset of clinical signs, well after higher-level accumulati ...201222238438
Factors influencing temporal variation of scrapie incidence within a closed Suffolk sheep flock.Several studies have shown that transmission of natural scrapie can occur vertically and horizontally, and that variations in scrapie incidence between and within infected flocks are mostly due to differences in the proportion of sheep with susceptible and resistant PRNP genotypes. This report presents the results of a 12-year period of scrapie monitoring in a closed flock of Suffolk sheep, in which only animals of the ARQ/ARQ genotype developed disease. Among a total of 120 of these, scrapie at ...201221918004
Increased Immunohistochemical Labelling for Prion Protein Occurs in Diverse Neurological Disorders of Sheep: Relevance for Normal Cellular PrP Function.The classical prion diseases (e.g. scrapie of sheep and goats and bovine spongiform encephalopathy of cattle) are characterized by the accumulation of abnormal forms of the prion protein (PrP), usually recognized by their relative resistance to proteolysis compared with the physiological cellular forms of PrP. However, novel prion diseases have been detected in sheep, cattle and man, in which the abnormal PrP has less resistance to proteolysis than identified previously. These more subtle differ ...201122000036
Detection of PrPres in Genetically Susceptible Fetuses from Sheep with Natural Scrapie.Scrapie is a transmissible spongiform encephalopathy with a wide PrPres dissemination in many non-neural tissues and with high levels of transmissibility within susceptible populations. Mechanisms of transmission are incompletely understood. It is generally assumed that it is horizontally transmitted by direct contact between animals or indirectly through the environment, where scrapie can remain infectious for years. In contrast, in utero vertical transmission has never been demonstrated and ha ...201122194786
Sensitive and specific detection of sporadic Creutzfeldt-Jakob disease brain prion protein using real-time quaking induced conversion.Real-time quaking induced conversion (RT-QuIC) is an assay in which disease-associated prion protein initiates a rapid conformational transition in recombinant prion protein resulting in the formation of amyloid that can be monitored in real time using the dye thioflavin T. It therefore has potential advantages over analogous cell-free prion protein conversion assays such as protein misfolding cyclic amplification (PMCA). The QuIC assay and the related amyloid seeding assay have largely been dev ...201122031526
experimental interspecies transmission studies of the transmissible spongiform encephalopathies to cattle: comparison to bovine spongiform encephalopathy in cattle.prion diseases or transmissible spongiform encephalopathies (tses) of animals include scrapie of sheep and goats; transmissible mink encephalopathy (tme); chronic wasting disease (cwd) of deer, elk and moose; and bovine spongiform encephalopathy (bse) of cattle. the emergence of bse and its spread to human beings in the form of variant creutzfeldt-jakob disease (vcjd) resulted in interest in susceptibility of cattle to cwd, tme and scrapie. experimental cross-species transmission of tse agents p ...201121908269
prnp genetic variability and molecular typing of natural goat scrapie isolates in a high number of infected flocks.abstract: one hundred and four scrapie positive and 77 negative goats from 34 greek mixed flocks were analysed by prion protein gene sequencing and 17 caprine scrapie isolates from 11 flocks were submitted to molecular isolate typing. for the first time, the protective s146 variant was reported in greece, while the protective k222 variant was detected in negative but also in five scrapie positive goats from heavily infected flocks. by immunoblotting six isolates, including two goat flockmates ca ...201121961834
White-tailed deer are susceptible to the agent of sheep scrapie by intracerebral inoculation.ABSTRACT: Interspecies transmission studies afford the opportunity to better understand the potential host range and origins of prion diseases. The purpose of this experiment was to determine susceptibility of white-tailed deer to the agent of scrapie after intracerebral inoculation and to compare clinical signs and lesions to those reported for chronic wasting disease (CWD). Deer (n = 5) were inoculated with 1 mL of a 10% (wt/vol) brain homogenate derived from a sheep clinically affected with s ...201121988781
an overview of animal prion diseases.prion diseases are transmissible neurodegenerative conditions affecting human and a wide range of animal species. the pathogenesis of prion diseases is associated with the accumulation of aggregates of misfolded conformers of host-encoded cellular prion protein (prpc). animal prion diseases include scrapie of sheep and goats, bovine spongiform encephalopathy (bse) or mad cow disease, transmissible mink encephalopathy, feline spongiform encephalopathy, exotic ungulate spongiform encephalopathy, c ...201122044871
lower specific infectivity of protease-resistant prion protein generated in cell-free reactions.prions are unconventional infectious agents that cause transmissible spongiform encephalopathy (tse) diseases, or prion diseases. the biochemical nature of the prion infectious agent remains unclear. previously, using a protein misfolding cyclic amplification (pmca) reaction, infectivity and disease-associated protease-resistant prion protein (prpres) were both generated under cell-free conditions, which supported a nonviral hypothesis for the agent. however, these studies lacked comparative qua ...201122065744
caprine prion gene polymorphisms are associated with decreased incidence of classical scrapie in goat herds in the united kingdom.abstract: the application of genetic breeding programmes to eradicate transmissible spongiform encephalopathies in goats is an important aim for reasons of animal welfare as well as human food safety and food security. based on the positive impact of prnp genetics on sheep scrapie in europe in the past decade, we have established caprine prnp gene variation in more than 1100 goats from the united kingdom and studied the association of prnp alleles with disease phenotypes in 150 scrapie-positive ...201122040234
atypical scrapie isolates involve a uniform prion species with a complex molecular signature.the pathobiology of atypical scrapie, a prion disease affecting sheep and goats, is still poorly understood. in a previous study, we demonstrated that atypical scrapie affecting small ruminants in switzerland differs in the neuroanatomical distribution of the pathological prion protein (prp(d)). to investigate whether these differences depend on host-related vs. pathogen-related factors, we transmitted atypical scrapie to transgenic mice over-expressing the ovine prion protein (tg338). the clini ...201122096587
microsecond unfolding kinetics of sheep prion protein reveals an intermediate that correlates with susceptibility to classical scrapie.the microsecond folding and unfolding kinetics of ovine prion proteins (ovprp) were measured under various solution conditions. a fragment comprising residues 94-233 of the full-length ovprp was studied for four variants with differing susceptibilities to classical scrapie in sheep. the observed biexponential unfolding kinetics of ovprp provides evidence for an intermediate species. however, in contrast to previous results for human prp, there is no evidence for an intermediate under refolding c ...201121889460
infectious prion protein alters manganese transport and neurotoxicity in a cell culture model of prion disease.protein misfolding and aggregation are considered key features of many neurodegenerative diseases, but biochemical mechanisms underlying protein misfolding and the propagation of protein aggregates are not well understood. prion disease is a classical neurodegenerative disorder resulting from the misfolding of endogenously expressed normal cellular prion protein (prp(c)). although the exact function of prp(c) has not been fully elucidated, studies have suggested that it can function as a metal b ...201121871919
sex effects in mouse prion disease incubation time.prion disease incubation time in mice is determined by many factors including prp expression level, prnp alleles, genetic background, prion strain and route of inoculation. sex differences have been described in age of onset for vcjd and in disease duration for both vcjd and sporadic cjd and have also been shown in experimental models. the sex effects reported for mouse incubation times are often contradictory and detail only one strain of mice or prions, resulting in broad generalisations and a ...201122174884
inhibitors of gastric acid secretion increase the risk of prion infection in mice.gastric juice is a unique combination of hydrochloric acid and the proteolytic enzyme pepsin. its main function is to inactivate ingested microorganisms. prions cause fatal transmissible degenerative encephalopathies in animals and man. these diseases have attracted attention due to the proposed link between bovine spongiform encephalopathy in cattle and the occurrence of a new variant creutzfeldt-jakob disease in humans where the most probable route of transmission is via contaminated food. the ...201121936725
heart rate variability analysis in sheep affected by transmissible spongiform encephalopathies.abstract:201122168827
abrogation of complex glycosylation by swainsonine results in strain- and cell-specific inhibition of prion replication.neuroblastoma-derived n2a-pk1 cells, fibroblastic ld9 cells, and cns-derived cad5 cells can be infected efficiently and persistently by various prion strains, as measured by the standard scrapie cell assay. swainsonine, an inhibitor of golgi α-mannosidase ii that causes abnormal n-glycosylation, strongly inhibits infection of pk1 cells by rml, 79a and 22f, less so by 139a, and not at all by 22l prions, and it does not diminish propagation of any of these strains in ld9 or cad5 cells. misglycosyl ...201121930694
upregulation of micro rna-146a (mirna-146a), a marker for inflammatory neurodegeneration, in sporadic creutzfeldt-jakob disease (scjd) and gerstmann-straussler-scheinker (gss) syndrome.a mouse- and human-brain-abundant, nuclear factor (nf)-кb-regulated, micro rna-146a (mirna-146a) is an important modulator of the innate immune response and inflammatory signaling in specific immunological and brain cell types. levels of mirna-146a are induced in human brain cells challenged with at least five different species of single- or double-stranded dna or rna neurotrophic viruses, suggesting a broad role for mirna-146a in the brain's innate immune response and antiviral immunity. upregu ...201122043907
prpsc detection in formalin-fixed paraffin-embedded tissue by elisa.abstract:201122018205
classical scrapie prions in ovine blood are associated with b lymphocytes and platelet-rich plasma.classical scrapie is a naturally occurring transmissible spongiform encephalopathy of sheep and goats characterized by cellular accumulation of abnormal isoforms of prion protein (prpsc) in the central nervous system and the follicles of peripheral lymphoid tissues. previous studies have shown that the whole blood and buffy coat blood fraction of scrapie infected sheep harbor prion infectivity. although prpsc has been detected in peripheral blood mononuclear cells (pbmcs), plasma, and more recen ...201122112371
immunophenotype of cells within cervine rectoanal mucosa-associated lymphoid tissue and mesenteric lymph nodes.rectoanal mucosa-associated lymphoid tissue (ramalt) is a part of the lymphoid system that can be sampled easily in live animals, especially ruminants. ramalt biopsy is useful for the diagnosis of transmissible spongiform encephalopathies, including scrapie in sheep and goats and chronic wasting disease (cwd) in cervids. diagnosis is reliant on detection of abnormal prion protein (prp(d)), which is associated with lymphoid follicles. for enzyme linked immunosorbent assays (elisas) detecting prp( ...201122000034
effects of a brain-engraftable microglial cell line expressing anti-prion scfv antibodies on survival times of mice infected with scrapie prions.we first verified that a single chain fv fragment against prion protein (anti-prp scfv) was secreted by hek293t cells and prevented prion replication in infected cells. we then stably expressed anti-prp scfv in brain-engraftable murine microglial cells and intracerebrally injected these cells into mice before or after infection with prions. interestingly, the injection before or at an early time point after infection attenuated the infection marginally but significantly prolonged survival times ...201121516351
fate of prions in soil: a review.prions are the etiological agents of transmissible spongiform encephalopathies (tsses), a class of fatal neurodegenerative diseases affecting humans and other mammals. the pathogenic prion protein is a misfolded form of the host-encoded prion protein and represents the predominant, if not sole, component of the infectious agent. environmental routes of tse transmission areimplicated in epizootics of sheep scrapie and chronic wasting disease (cwd) of deer, elk, and moose. soil represents a plausi ...201121520752
effects of solution chemistry and aging time on prion protein adsorption and replication of soil-bound prions.prion interactions with soil may play an important role in the transmission of chronic wasting disease (cwd) and scrapie. prions are known to bind to a wide range of soil surfaces, but the effects of adsorption solution chemistry and long-term soil binding on prion fate and transmission risk are unknown. we investigated hy tme prion protein (prp(sc)) adsorption to soil minerals in aqueous solutions of phosphate buffered saline (pbs), sodium chloride, calcium chloride, and deionized water using w ...201121526178
probing structural differences between prp(c) and prp(sc) by surface nitration and acetylation: evidence of conformational change in the c-terminus.we used two chemical modifiers, tetranitromethane (tnm) and acetic anhydride (ac(2)o), which specifically target accessible tyrosine and lysine residues, respectively, to modify recombinant syrian hamster prp(90-231) [rshaprp(90-231)] and shaprp 27-30, the proteinase k-resistant core of prp(sc) isolated from brain of scrapie-infected syrian hamsters. our aim was to find locations of conformational change. modified proteins were subjected to in-gel proteolytic digestion with trypsin or chymotryps ...201121526750
replication and spread of cjd, kuru and scrapie agents in vivo and in cell culture.transmissible spongiform encephalopathy (tse) agents are defined by their virulence for particular species, their spread in the population, their incubation time to cause disease, and their neuropathological sequelae. murine adapted human agents, including sporadic cjd (scjd), new guinea kuru, and japanese cjd agents, display particularly distinct incubation times and maximal infectious brain titers. they also induce agent-specific patterns of neurodegeneration. when these tse agents are transmi ...201121527829
genetics of prion disease.prion diseases or transmissible spongiform encephalopathies (tses) are neurodegenerative disorders of humans and animals for which there are no effective treatments or cure. they include creutzfeldt-jakob disease (cjd) in humans and sheep scrapie, bovine spongiform encephalopathy (bse) and chronic wasting disease (cwd) in cervids. the prion protein (prp) is central to the disease process. an abnormal form of prp is generally considered to be the sole or principal component of the infectious agen ...201121528440
experimental oral transmission of atypical scrapie to sheep.to investigate the possibility of oral transmission of atypical scrapie in sheep and determine the distribution of infectivity in the animals' peripheral tissues, we challenged neonatal lambs orally with atypical scrapie; they were then killed at 12 or 24 months. screening test results were negative for disease-specific prion protein in all but 2 recipients; they had positive results for examination of brain, but negative for peripheral tissues. infectivity of brain, distal ileum, and spleen fro ...201121529394
genetic predisposition of some bulgarian sheep breeds to the scrapie disease.the aim of this study is to investigate the profile of ovine prp gene by amino acid polymorphism at codons 136, 141, 154, and 171 for determining the genetic predisposition to the scrapie disease for the tribal sheep and rams, with different numbers and distribution in bulgaria. three hundred twenty four animals originating from 41 tribal herds comprising eight breeds were included in the study. dna was isolated from blood samples specifically amplified by pcr and sequenced. the alignments of co ...201121533749
effect of glycans and the glycophosphatidylinositol anchor on strain dependent conformations of scrapie prion protein: improved purifications and infrared spectra.mammalian prion diseases involve conversion of normal prion protein, prp(c), to a pathological aggregated state (prp(res)). the three-dimensional structure of prp(res) is not known, but infrared (ir) spectroscopy has indicated high, strain-dependent β-sheet content. prp(res) molecules usually contain a glycophosphatidylinositol (gpi) anchor and large asn-linked glycans, which can also vary with strain. using ir spectroscopy, we tested the conformational effects of these post-translational modifi ...201121539311
initial fate of prions upon peripheral infection: half-life, distribution, clearance, and tissue uptake.prion diseases are infectious neurodegenerative disorders associated with the misfolded prion protein (prp(sc)), which appears to be the sole component of the infectious agent (termed prion). to produce disease, prions have to be absorbed into the body and reach sufficient quantities in the brain. very little is known about the biological mechanisms controlling the initial fate of prions. here, we studied the systemic pharmacokinetics and biodistribution of prp(sc) in vivo. after an intravenous ...201121555356
polymorphisms of the prion protein gene and their effects on litter size and risk evaluation for scrapie in chinese hu sheep.it is well known that scrapie is a fatal, neurodegenerative disease in sheep and goat, which belongs to the group of transmissible spongiform encephalopathies (tses) or prion diseases. it has been confirmed that the polymorphisms of prion protein gene (prnp) at codons 136, 154, and 171 have strong relationship with scrapie in sheep. in the present study, nine polymorphisms of prnp at codons 136, 154, and 171 and other six loci (at codons 101, 112, 127, 137, 138, and 152) were detected in 180 chi ...201121556743
prion disease blood test using immunoprecipitation and improved quaking-induced conversion.abstract a key challenge in managing transmissible spongiform encephalopathies (tses) or prion diseases in medicine, agriculture, and wildlife biology is the development of practical tests for prions that are at or below infectious levels. of particular interest are tests capable of detecting prions in blood components such as plasma, but blood typically has extremely low prion concentrations and contains inhibitors of the most sensitive prion tests. one of the latter tests is quaking-induced co ...201121558432
heparin enhances the cell-protein misfolding cyclic amplification efficiency of variant creutzfeldt-jakob disease.highly sensitive in vitro screening tests are required to prevent the iatrogenic spread of variant creutzfeldt-jakob disease (vcjd). protein misfolding cyclic amplification (pmca) is a candidate for such a test, but the sensitivity of this method is insufficient. polyanions were reported to enhance pmca efficiency, but their effects on vcjd are unclear. we developed a cell-pmca of vcjd, wherein cell lysate containing exogenously expressed human prp was used as substrates, to investigate the effe ...201121565253
an enzymatic treatment of soil-bound prions effectively inhibits replication.chronic wasting disease (cwd) and scrapie can be transmitted through indirect environmental routes, possibly via soil, and a practical decontamination strategy for prion-contaminated soil is currently unavailable. in the laboratory, an enzymatic treatment under environmentally-relevant conditions (22°c, ph 7.4) can degrade soil-bound prp(sc) below the limits of western blot detection. we developed and used a quantitative serial protein misfolding cyclic amplification (pmca) protocol to character ...201121571886
detection and localisation of prp in the liver of sheep infected with scrapie and bovine spongiform encephalopathy.prions are largely contained within the nervous and lymphoid tissue of transmissible spongiform encephalopathy (tse) infected animals. however, following advances in diagnostic sensitivity, prp(sc), a marker for prion disease, can now be located in a wide range of viscera and body fluids including muscle, saliva, blood, urine and milk, raising concerns that exposure to these materials could contribute to the spread of disease in humans and animals. previously we demonstrated low levels of infect ...201121589864
detection of prions in the faeces of sheep naturally infected with classical scrapie.abstract: classical scrapie is a naturally transmitted prion disease of sheep and goats. contaminated environments may contribute to the spread of disease and evidence from animal models has implicated urine, blood, saliva, placenta and faeces as possible sources of the infection. here we sought to determine whether sheep naturally infected with classical scrapie shed prions in their faeces. we used serial protein misfolding cyclic amplification (spmca) along with two extraction methods to exami ...201121592355
detection of four novel polymorphisms in prp gene of pakistani sheep (damani and hashtnagri) and goats (kamori and local hairy) breeds.abstract: scrapie is a fatal neurodegenerative disorder of sheep and goats caused by post-translational conformational change in the host-encoded prion protein (prpc). susceptibility or resistance to scrapie has been associated with the presence of polymorphisms in the prion protein (prp) gene. in the present study, we analyzed the prp gene sequence to determine the frequency of polymorphisms in 56 sheep (28 each from damani and hashtnagri breeds) and 56 goats (28 each from kamori and local hair ...201121595993
atypical prion diseases in humans and animals.although prion diseases, such as creutzfeldt-jakob disease (cjd) in humans and scrapie in sheep, have long been recognized, our understanding of their epidemiology and pathogenesis is still in its early stages. progress is hampered by the lengthy incubation periods and the lack of effective ways of monitoring and characterizing these agents. protease-resistant conformers of the prion protein (prp), known as the "scrapie form" (prp(sc)), are used as disease markers, and for taxonomic purposes, in ...201121598097
lack of a-disintegrin-and-metalloproteinase adam10 leads to intracellular accumulation and loss of shedding of the cellular prion protein in vivo.abstract: background: the cellular prion protein (prpc) fulfils several yet not completely understood physiological functions. apart from these functions, it has the ability to misfold into a pathogenic scrapie form (prpsc) leading to fatal transmissible spongiform encephalopathies. proteolytic processing of prpc generates n- and c-terminal fragments which play crucial roles both in the pathophysiology of prion diseases and in transducing physiological functions of prpc. a-disintegrin-and-metall ...201121619641
gene expression profiling and association with prion-related lesions in the medulla oblongata of symptomatic natural scrapie animals.the pathogenesis of natural scrapie and other prion diseases remains unclear. examining transcriptome variations in infected versus control animals may highlight new genes potentially involved in some of the molecular mechanisms of prion-induced pathology. the aim of this work was to identify disease-associated alterations in the gene expression profiles of the caudal medulla oblongata (mo) in sheep presenting the symptomatic phase of natural scrapie. the gene expression patterns in the mo from ...201121629698
clinical, electroretinographic and histomorphometric evaluation of the retina in sheep with natural scrapie.abstract: background: the retina is part of the diencephalon in a peripheral location and may be involved in prion diseases. retinal function and structural changes were assessed in naturally scrapie-affected red face manech ewes presenting the classical signs of the disease, and clinically healthy age-matched subjects for controls. ophthalmic examination was done prior to electroretinography (erg), which was carried out under conditions that allowed photopic and scotopic activities to be assess ...201121639947
estimation of variant creutzfeldt-jakob disease infectivity titers in human blood.background: blood of individuals with variant creutzfeldt-jakob disease (vcjd) is infectious but the titer is unknown. current estimates of possible vcjd infectivity titers in blood have largely relied on an assumption that the titers of vcjd agent in human blood are likely to be similar to those in blood of rodents infected with model transmissible spongiform encephalopathy agents, assayed by intracerebral inoculations of rodents of the same species. study design and methods: we analyzed publis ...201121645006
mechanism of prp-amyloid formation in mice without transmissible spongiform encephalopathy.gerstmann-sträussler-scheinker (gss) p102l disease is a familial form of a transmissible spongiform encephalopathy (tse) that can present with or without vacuolation of neuropil. inefficient disease transmission into 101ll transgenic mice was previously observed from gss p102l without vacuolation. however several aged, healthy mice had large plaques composed of abnormal prion protein (prp(d) ). here we perform the ultrastructural characterisation of such plaques and compare them with prp(d ) agg ...201121645162
photodegradation illuminates the role of polyanions in prion infectivity.understanding the mechanism by which prion infectivity is encoded by the misfolded protein prp (sc ) remains a high priority within the prion field. work from several groups has indicated cellular cofactors may be necessary to form infectious prions in vitro. the identity of endogenous prion conversion cofactors is currently unknown, but may include polyanions and/or lipid molecules. in a recent study, we manufactured infectious hamster prions containing purified prp (sc) , co-purified lipid, an ...201121646861
quantitative detection and biological propagation of scrapie seeding activity in vitro facilitate use of prions as model pathogens for disinfection.prions are pathogens with an unusually high tolerance to inactivation and constitute a complex challenge to the re-processing of surgical instruments. on the other hand, however, they provide an informative paradigm which has been exploited successfully for the development of novel broad-range disinfectants simultaneously active also against bacteria, viruses and fungi. here we report on the development of a methodological platform that further facilitates the use of scrapie prions as model path ...201121647368
uptake dynamics of scrapie agent in the intestinal villous epithelium of suckling and weanling syrian hamsters.in mice, the number of intestinal villous columnar epithelium cells that incorporate abnormal prion protein (prp(sc) ) decreases significantly after weaning. in this study, to investigate the dynamics of prp(sc) uptake during the growth of hamsters, scrapie 263k agent was inoculated orally into suckling and weanling syrian hamsters and the number of prp(sc) -positive villous epithelium cells was estimated immunohistochemically. the number of prp(sc) -positive cells declined significantly as the ...201121668484
characterization of prnp and sprn coding regions from atypical scrapie cases diagnosed in poland.scrapie, a fatal transmissible spongiform encephalopathy (tse) occurs in two phenotypes: classical and atypical. many authors point out that the polymorphism of three codons (136, 154, 171) of the prnp (prp gene) is associated with a sheep susceptibility to classical scrapie. until now, only one prnp gene variant coding phenylalanine at codon 141 has been found to be associated with atypical scrapie. another recently identified and interesting candidate gene for scrapie susceptibility in sheep i ...201121674189
bovine spongiform encephalopathy: is it time to relax bse-related measures in the context of international trade?bovine spongiform encephalopathy (bse) has presented serious challenges to both the world organisation for animal health and national governments, in defining and implementing appropriate national control measures, and in agreeing trade rules that permit safe trade in cattle and bovine products. precautionary trade rules were initially necessary, based upon the science of sheep scrapie, but research into bse later enabled bse-specific trade rules to be developed. as a result, current rules on tr ...201121809757
biochemical and strain properties of cjd prions: complexity versus simplicity.prions, the agents responsible for transmissible spongiform encephalopathies, are infectious proteins consisting primarily of scrapie prion protein (prp(sc) ), a misfolded, beta-sheet enriched and aggregated form of the host-encoded cellular prion protein (prp(c) ). their propagation is based on an autocatalytic prp conversion process. despite the lack of a nucleic acid genome, different prion strains have been isolated from animal diseases. increasing evidence supports the view that strain-spec ...201121790605
exosome-producing follicle associated epithelium is not involved in uptake of prpd from the gut of sheep (ovis aries): an ultrastructural study.in natural or experimental oral scrapie infection of sheep, disease associated prion protein (prp(d)) often first accumulates in peyer's patch (pp) follicles. the route by which infectivity reaches the follicles is unknown, however, intestinal epithelial cells may participate in intestinal antigenic presentation by delivering exosomes as vehicles of luminal antigens. in a previous study using an intestinal loop model, following inoculation of scrapie brain homogenate, inoculum associated prp(d) ...201121789232
cytokine antibody array analysis in brain and periphery of scrapie-infected tg338 mice.scrapie is a prion-associated transmissible spongiform encephalopathy (tse) of sheep and goats, and frequently serves as a comparative model for other prion diseases, such as chronic wasting disease and bovine spongiform encephalopathy. tses are unique neurologic disorders that do not appear to be accompanied by robust systemic immunologic responses. mrna data suggest that cytokines are involved in scrapie progression. in this study, brain tissue, mesenteric lymph nodes, splenic tissue and serum ...201121788075
allelic frequency and genotypes of prion protein at codon 136 and 171 in iranian ghezel sheep breeds.prp genotypes at codons 136 and 171 in one hundred twenty iranian ghezel sheep breeds were studied using allele-specific pcr amplification and compared with the well-known sheep breeds in north america, the united states, and europe. the frequency of v allele and vv genotype at codon 136 of ghezel sheep breed was significantly lower than aa and av. at codon 171, the frequency of allele h was significantly lower than q and r. despite the similarities of prp genotypes at codons 136 and 171 between ...201121778818
histopathological studies of "ch1641-like" scrapie sources versus classical scrapie and bse transmitted to ovine transgenic mice (tgovprp4).the possibility of the agent causing bovine spongiform encephalopathy (bse) infecting small ruminants is of serious concern for human health. among scrapie cases, the ch1641 source in particular appears to have certain biochemical properties similar to the bse strain. in france, several natural scrapie cases were identified as "ch1641-like" natural scrapie isolates in sheep and goats. the tg(ovprp4) mouse line expressing the ovine prion protein is a sensitive model for studying and identifying s ...201121765939
amyloid: little proteins, big clues. 201121760575
from high-throughput cell culture screening to mouse model: identification of new inhibitor classes against prion disease.transmissible spongiform encephalopathies (tse) or prion diseases belong to a category of fatal and so far untreatable neurodegenerative conditions. all prion diseases are characterized by both degeneration in the central nervous system (cns) in humans and animals and the deposition and accumulation of proteinase k-resistant prion protein (prp(res) ). until now, no pharmaceutical product has been available to cure these diseases or to alleviate their associated symptoms. here, a cell-culture scr ...201121755599
characterization of the prnp gene locus in chios dairy sheep and its association with milk production and reproduction traits.the objective of this study was to examine the prion protein gene locus (prnp) in chios sheep. prnp is linked with scrapie resistance in small ruminants. here, its impact on milk production (test-day and total lactation yield) and reproduction (age at first lambing, conception rate at first service, and prolificacy) was assessed. genotyping at codons 136, 154 and 171 (classical scrapie) and 141 (atypical scrapie) was performed using dna from milk somatic cells and pcr-rflp analysis. a total of 1 ...201121749423
steric zipper formed by hydrophobic peptide fragment of syrian hamster prion protein.steric zippers, where the residues of two neighboring ß-sheet layers are tightly interdigitated, have been proposed as fundamental structural units of amyloid fibrils by eisenberg and co-workers. the steric zipper formed by polypeptides containing the palindromic sequence agaaaaga has a distinctive feature that the distance between two interdigitated ß-sheet layers is comparable to the interstrand distance of the individual ß-sheet. this structural motif is of great interest in the study of prio ...201121749158
diphenyl-pyrazole derived compounds increase survival time of mice after prion infection.transmissible spongiform encephalopathies (tses) represent a group of fatal neurodegenerative disorders which can be transmitted by natural infection or inoculation. tses include scrapie in sheep, bse in cattle, and creutzfeldt-jakob disease (cjd) in humans. the emergence of a variant form of cjd (vcjd) which has been associated to bse, produced strong pressure to search for effective treatments with new drugs. up to now, however, tses are incurable, although many efforts have been made in vitro ...201121746938
enhancement of immunohistochemical staining of scrapie proteins and immune cells within lymph nodes of early scrapie-infected sheep.transmissible spongiform encephalopathies (tse) are a group of fatal neurodegenerative diseases that affect animals as well as humans. the oldest of these diseases is scrapie seen in sheep. scrapie is caused by an altered form (prp(sc)), capable of inducing "self-replication" of the normal host prion protein(prp(c)). there is currently no universal standard for antigen retrieval when using immunohistochemistry to simultaneously stain the prp(c) protein and other cellular markers. the use of form ...201121722647
survival of infectious prions in water.the objective of this study was to evaluate the fate of infectious prions in water. known concentrations of infectious prions were added to deionized water, tap water, and wastewater. samples were incubated at 25-¦c, 37-¦c, and 50-¦c for 1 to 8 weeks. the standard scrapie cell assay (ssca) which includes the elispot (enzyme linked immuno-spot) reaction was performed to determine prion infectivity and quantity as a function of time. a reduction of infectious prions was observed at 25-¦c, 37-¦c, a ...201121707419
Refresh
firstprev
12345678910...
nextlast
Displaying items 1 - 100 of 4534