Objective To expatiate dynamic changes in hamsters infected with scrapie strain 263K,to observe the presence and aggravation of various forms of PrP and PrP^sc during incubation period,and to probe primarily the relat...Objective To expatiate dynamic changes in hamsters infected with scrapie strain 263K,to observe the presence and aggravation of various forms of PrP and PrP^sc during incubation period,and to probe primarily the relationship between the onset of clinic manifestations and the presence of different PrP^sc forms. Methods Hamster-adapted scrapie strain 263K was intracerebrally inoculated into hamsters. Different forms of PrP and PrP^sc were monitored dynamically by Western blot and immuno-histochemical assays. The presence of scrapie-associated fibril (SAF) was assayed by election microscopy analysis (EM) and immuno-golden EM.Results PrP^sc was initially detected in the brain tissues of the animals in 20 days post-inoculation by immunohistochemistry and 40 days with Western blot. Quantitative evaluations revealed that the amounts of PrP and PrP^sc in brain tissues increased along with the incubation.Several high and low molecular masses of PrP were seen in the brains of the long-life span infected animals. Deglycosylation assays identified that the truncated PrP in the infected brains showed similar glycosylation patterns as the full-length PrP. The presence of short fragments was seemed to relate with the onset of clinical conditions. Conclusion These results indicate that infectious agents exist and accumulate in central nerve system prior to the onset of the illness. Various molecular patterns of PrPs~ may indwell in brain tissues during the infection.展开更多
Objective To understand the infectious characteristics of a hamster-adapted scrapie strain 263K with five different routes of infection including intracerebral (i.c.), intraperitoneal (i.p.),intragastrical (i.g.), int...Objective To understand the infectious characteristics of a hamster-adapted scrapie strain 263K with five different routes of infection including intracerebral (i.c.), intraperitoneal (i.p.),intragastrical (i.g.), intracardiac and intramuscular (i.m.) approaches. Methods Hamsters were infected with crude- or fine-prepared brain extracts. The neuropathological changes, PrP^sc deposits,and patterns of PK-resistant PrP were analyzed by HE stain, immunohistochemistry (HC) assay and Western blot. Reactive gliosis and neuron loss were evaluated by glial fibfillary acidic protein (GFAP) and neuron specific enolase (NSE) specific IHC.Results The animals inoculated in i.m. and i.p.ways with crude PrP^sc extracts showed clinical signs at the average incubation of 69.2±2.8 and 65.5±3.9 days. Inoculation in i.c. and intracardiac ways with fine PrP^sc extracts (0.00035g) caused similar,but relative long incubation of around 90 days. Only one out of eight hamsters challenged in i.g way with low dosage (0.01g) became ill after a much longer incubation (185d), while all animals (4/4)with high dosage (0.04g) developed clinical signs 105 days postirrfection. The most remarkable spongiform degeneration and PrP^sc deposits were found in brain stem among the five challenge groups generally. The number of GFAP-positive astrocytes increased distinctly in brain stems in all infection groups, while the number of NSE-positive cells decreased significantly in cerebrum, except i.c. group. The patterns of PK-resistant PrP in brains were basically identical among the five infection routes. Conclusion Typical TSE could be induced in hamsters by inoculating strain 263K in the five infection ways.The incubation periods in bioassays depend on infective dosage, administrating pathway and preparation of PrP^sc.The neuropathological changes and PrP^sc deposits seem to be related with regions and inoculating pathways.展开更多
Objective To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Methods Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were press...Objective To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Methods Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were pressed into wafers. One hundred μL 106 TCID50/mL SARS-CoV, 100 μL 106 PFU/mL recombinant baculovirus expressing hamster’s prion protein (haPrP) protein and roughly 106 E. coli were slowly dropped onto the surfaces of the catalyst wafers and exposed for 5 and 20 min, respectively. After eluted from the surfaces of wafers, the infectivity of viruses and propagation of bacteria were measured. The expression of PrP protein was determined by Western blot. The morphological changes of bacteria were observed by electronic microscopy. Results After exposure to the catalysts surfaces for 5 and 20 min, the infectivity of SARS-CoV in Vero cells and baculovirus in Sf9 cells dropped down to a very low and undetectable level, and no colony was detected using bacteria culture method. The expression of haPrP protein reduced to 21.8% in the preparation of Sf9 cells infected with recombinant baculovirus exposed for 5 min and was undetectable exposed for 20 min. Bacterial membranes seemed to be cracked and the cytoplasm seemed to be effluent from cell bodies. Conclusion Exposures to the surfaces of Ag/Al2O3 and Cu/Al2O3 destroy the replication and propagation abilities of SARS-CoV, baculovirus and E. coli. Inactivation ability of metal catalysts needs to interact with air, utilizing oxygen molecules in air. Efficiently killing viruses and bacteria on the surfaces of the two metal catalysts has a promising potential for air-disinfection in hospitals, communities, and households.展开更多
基金This work was supported by the National Natural Science Foundation of China, No. 39928018, 30070038 and 30130070, National High-tech Research Development Program (863 Program), No. 2001AA215391, and EU Project QLRT, No. 200001441.
文摘Objective To expatiate dynamic changes in hamsters infected with scrapie strain 263K,to observe the presence and aggravation of various forms of PrP and PrP^sc during incubation period,and to probe primarily the relationship between the onset of clinic manifestations and the presence of different PrP^sc forms. Methods Hamster-adapted scrapie strain 263K was intracerebrally inoculated into hamsters. Different forms of PrP and PrP^sc were monitored dynamically by Western blot and immuno-histochemical assays. The presence of scrapie-associated fibril (SAF) was assayed by election microscopy analysis (EM) and immuno-golden EM.Results PrP^sc was initially detected in the brain tissues of the animals in 20 days post-inoculation by immunohistochemistry and 40 days with Western blot. Quantitative evaluations revealed that the amounts of PrP and PrP^sc in brain tissues increased along with the incubation.Several high and low molecular masses of PrP were seen in the brains of the long-life span infected animals. Deglycosylation assays identified that the truncated PrP in the infected brains showed similar glycosylation patterns as the full-length PrP. The presence of short fragments was seemed to relate with the onset of clinical conditions. Conclusion These results indicate that infectious agents exist and accumulate in central nerve system prior to the onset of the illness. Various molecular patterns of PrPs~ may indwell in brain tissues during the infection.
基金This work was supported by Chinese National Natural Science Foundation Grants 39928018,30070038 and 30130070, National High-tech Development Project (863 Project) 2001AA215391EU Project QLRT 2000 01441.
文摘Objective To understand the infectious characteristics of a hamster-adapted scrapie strain 263K with five different routes of infection including intracerebral (i.c.), intraperitoneal (i.p.),intragastrical (i.g.), intracardiac and intramuscular (i.m.) approaches. Methods Hamsters were infected with crude- or fine-prepared brain extracts. The neuropathological changes, PrP^sc deposits,and patterns of PK-resistant PrP were analyzed by HE stain, immunohistochemistry (HC) assay and Western blot. Reactive gliosis and neuron loss were evaluated by glial fibfillary acidic protein (GFAP) and neuron specific enolase (NSE) specific IHC.Results The animals inoculated in i.m. and i.p.ways with crude PrP^sc extracts showed clinical signs at the average incubation of 69.2±2.8 and 65.5±3.9 days. Inoculation in i.c. and intracardiac ways with fine PrP^sc extracts (0.00035g) caused similar,but relative long incubation of around 90 days. Only one out of eight hamsters challenged in i.g way with low dosage (0.01g) became ill after a much longer incubation (185d), while all animals (4/4)with high dosage (0.04g) developed clinical signs 105 days postirrfection. The most remarkable spongiform degeneration and PrP^sc deposits were found in brain stem among the five challenge groups generally. The number of GFAP-positive astrocytes increased distinctly in brain stems in all infection groups, while the number of NSE-positive cells decreased significantly in cerebrum, except i.c. group. The patterns of PK-resistant PrP in brains were basically identical among the five infection routes. Conclusion Typical TSE could be induced in hamsters by inoculating strain 263K in the five infection ways.The incubation periods in bioassays depend on infective dosage, administrating pathway and preparation of PrP^sc.The neuropathological changes and PrP^sc deposits seem to be related with regions and inoculating pathways.
基金This work was supported by the National High-Technology Research and Development Program of China (863 Program) 2003AA208402 and2003AA208201.
文摘Objective To study the two metal catalysts Ag/Al2O3 and Cu/Al2O3 that interdict the transmission pathway for SARS and other respiratory infectious diseases. Methods Two metal catalysts Ag/Al2O3 and Cu/Al2O3 were pressed into wafers. One hundred μL 106 TCID50/mL SARS-CoV, 100 μL 106 PFU/mL recombinant baculovirus expressing hamster’s prion protein (haPrP) protein and roughly 106 E. coli were slowly dropped onto the surfaces of the catalyst wafers and exposed for 5 and 20 min, respectively. After eluted from the surfaces of wafers, the infectivity of viruses and propagation of bacteria were measured. The expression of PrP protein was determined by Western blot. The morphological changes of bacteria were observed by electronic microscopy. Results After exposure to the catalysts surfaces for 5 and 20 min, the infectivity of SARS-CoV in Vero cells and baculovirus in Sf9 cells dropped down to a very low and undetectable level, and no colony was detected using bacteria culture method. The expression of haPrP protein reduced to 21.8% in the preparation of Sf9 cells infected with recombinant baculovirus exposed for 5 min and was undetectable exposed for 20 min. Bacterial membranes seemed to be cracked and the cytoplasm seemed to be effluent from cell bodies. Conclusion Exposures to the surfaces of Ag/Al2O3 and Cu/Al2O3 destroy the replication and propagation abilities of SARS-CoV, baculovirus and E. coli. Inactivation ability of metal catalysts needs to interact with air, utilizing oxygen molecules in air. Efficiently killing viruses and bacteria on the surfaces of the two metal catalysts has a promising potential for air-disinfection in hospitals, communities, and households.
