Abnormal tubulovesicular particles in brains of hamsters with scrapie

Abnormal tubulovesicular particles of an average diameter of 23 nm have been observed in brains of mice with scrapie as well as in other animals with spongiform encephalopathies, but they were thought to be absent from the brains of hamsters with scrapie in which the highest known concentrations of the infectious agent occur. We observed in neuronal processes of hamsters as well as mice clusters of those tubulovesicular structures, most often in postsynaptic terminals. Such particles have now been seen regularly in both experimental and natural scrapie in all species examined as well as in other spongiform encephalopathies.     

Widespread PrPSc accumulation in muscles of hamsters orally infected with scrapie

Scrapie, bovine spongiform encephalopathy and chronic wasting disease are orally communicable, transmissible spongiform encephalopathies (TSEs). As zoonotic transmissions of TSE agents may pose a risk to human health, the identification of reservoirs for infectivity in animal tissues and their exclusion from human consumption has become a matter of great importance for consumer protection. In this study, a variety of muscles from hamsters that were orally challenged with scrapie was screened for the presence of a molecular marker for TSE infection, PrP^Sc (the pathological isoform of the prion protein PrP). Sensitive western blotting revealed consistent PrP^Sc accumulation in skeletal muscles from forelimb and hindlimb, head, back and shoulder, and in tongue. Previously, our animal model has provided substantial baseline information about the peripheral routing of infection in naturally occurring and orally acquired ruminant TSEs. Therefore, the findings described here highlight further the necessity to investigate thoroughly whether muscles of TSE-infected sheep, cattle, elk and deer contain infectious agents.     

A rapid and efficient method to enrich SAF-protein from scrapie brains of hamsters

Scrapie hamster brains contain at least 5–10 g of scrapie-associated fibrils (SAF) per brain as estimated by the amount of its major constituent, a protein of about 26 000 daltons (SAF-protein). It can be extracted efficiently by a 10% solution of sarkosyl and can be enriched by differentia] centrifugation and buffer extraction. Scrapie infectivity, SAF, and SAF-protein copurify.     

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, the dynamics of PrP(Sc) uptake during the growth of hamsters were investigated by inoculating scrapie 263K agent orally into suckling and weanling Syrian hamsters and estimating the number of PrP(Sc) -positive villous epithelium cells immunohistochemically. The number of PrP(Sc) -positive cells declined significantly as the hamsters aged. The present results suggest that a tendency toward decline of PrP(Sc) -positive cells with increasing age might be a common phenomenon among the superfamily Muridae.     

Comparison of NADPH diaphorase activity in the brains of hamsters infected with scrapie strains 139H or 263K or with normal hamster brain homogenate

Previous studies showed that the histopathological changes found in the brains of scrapie-infected animals included amyloid plaque formation, vacuolation, gliosis and neuronal and neurite degeneration. There were differences in the histopathological findings as a function of the scrapie strain-host combination. NADPH-diaphorase (NADPH-d) has been shown to be a selective histochemical marker for neurons containing nitric oxide (NO) synthase. Neuronal cell damage caused by NOS in brain has been reported to be associated with many neurodegenerative diseases. In this study, we used NADPH-d histostaining to investigate changes in the NOS system in brains of 139H- and 263K-infected hamsters and compared the results to normal hamster brain (NHB) injected animals. We observed that some of the NADPH-d histostaining neurons in the cortex of scrapie-infected hamsters appeared to be atrophic: the neurons were smaller and had fewer neurites. The NADPH-d histostaining intensity of neurons or astrocytes in septum, thalamus, hypothalamus and amygdala of 139H- and 263K-infected hamsters was greater than in control hamsters. Astrocytes in the thalamus, hypothalamus and lower part of the cortex (layers 4 to 6) in 263K-infected hamsters were more intensely stained for NADPH-d than in either 139H-infected hamsters or controls. Our results suggest that changes in NADPH-d system might play a role in the diversity of scrapie induced neurodegenerative changes.     

Proteomic profiling of PrP27‐30‐enriched preparations extracted from the brain of hamsters with experimental scrapie

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative disorders characterized by the accumulation in the CNS of a pathological conformer (PrP^TSE) of the host‐encoded cellular prion protein (PrP^C). PrP^TSE has a central role in the pathogenesis of the disease but other factors are likely involved in the pathological process. In this work we employed a multi‐step proteomic approach for the identification of proteins that co‐purify with the protease‐resistant core of PrP^TSE (PrP27‐30) extracted from brains of hamsters with experimental scrapie. We identified ferritin, calcium/calmodulin‐dependent protein kinase α type II, apolipoprotein E, and tubulin as the major components associated with PrP27‐30 but also trace amounts of actin, cofilin, Hsp90α, the γ subunit of the T‐complex protein 1, glyceraldehyde 3‐phosphate dehydrogenase, histones, and keratins. Whereas some of these proteins (tubulin and ferritin) are known to bind PrP, other proteins (calcium/calmodulin‐dependent protein kinase α type II, Hsp90α) may associate with PrP^TSE fibrils during disease. Apolipoprotein E and actin have been previously observed in association with PrP^TSE, whereas cofilin and actin were shown to form abnormal rods in the brain of patients with Alzheimer disease. The roles of these proteins in the development of brain lesions are still unclear and further work is needed to explain their involvement in the pathogenesis of TSEs.     

Immunoglobulins anti-Anisakis simplex in patients with gastrointestinal diseases

The nematode Anisakis simplex causes anisakidiasis, a disease that often mimics other gastrointestinal diseases. Patients with digestive haemorrhaging, Crohn's disease, digestive cancer and appendicitis were analysed for antibodies to A. simplex. Antibody detection was carried out by enzyme-linked immunosorbent assay (ELISA) and immunoblotting using crude extract (CE) antigen and excretory-secretory (ES) products. Total immunoglobulin (Igs), IgG, IgM, IgA and IgE were studied. The highest percentage was obtained when Igs were tested against CE antigen. A higher percentage of positivity was observed with the appendicitis group. The Crohn's disease group showed the highest levels of IgG against the ES antigen. Using immunoblotting, 24% and 48% of sera from patients with symptoms of Crohn's disease and digestive haemorrhaging, respectively, showed a positive immunorecognition pattern of CE antigen. The prevalence of detectable antibodies against A. simplex is higher in patients with digestive disorders than in the healthy population. A linear correlation was observed between prothrombin activity and Igs-CE, IgA-CE and IgA-ES but not between IgE-CE and the other immunoglobulin levels. Specific IgA is associated with a higher activity index of Crohn's disease. Specific antibodies were observed against A. simplex in patients with appendicitis and gastrointestinal cancer, indicating a higher rate of positivity for IgA.     

Differentiating blood samples from scrapie infected and non-infected hamsters by detecting disease-associated prion proteins using Multimer Detection System

This communication describes the application of a modified sandwich enzyme-linked immunosorbent assay (ELISA), termed Multimer Detection System (MDS) for the detection of disease-associated multimeric forms of the prion protein (PrPd) in hamster blood. PrPd was detected in plasma of prion-affected hamsters while MDS revealed no PrPd in identically-treated plasma of healthy animals. This is the first report of a single ELISA- based immune detection of PrPd from blood samples.     

Immunoglobulins in the Eastern Carolines

Serum samples from Micronesian populations on the Pingelap, Mokil, Ponape and Kusaie islands were tested for the immunoglobulin G (IgG) allotypes, Gm (1, 2, 3, 5, 6, 13, 14, 21), and for Inv (1). All four populations have the Gm phenogroups, Gm^1,21, Gm^1,2,21, Gm^1,3,5,13,14, and Gm^1,5,6. The Ponapeans have Gm^1,5,13,14 also. Pedigree analysis shows that the Gm^1,5,6 phenogroup in the Pingelap and Mokil populations is derived from the single offspring of a member of a crew of a whaling ship and that the Gm^1,2,21 phenogroup was introduced by three non-native individuals. The Gm allotypes indicate that the Ponapean and Kusiean populations also have phenogroups from other races, and historical data show that there has been adequate opportunity for this to have occurred. Only the phenogroups Gm^1,21 and Gm^1,5,13,14 appear to be endemic to eastern Micronesia.