Eight patients have been studied during the first 6 weeks of rheumatoid synovitis. All of them exhibited microvascular injury, which was manifested by gaps between endothelial cells, vascular occlusion, erythrocyte ex...
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Eight patients have been studied during the first 6 weeks of rheumatoid synovitis. All of them exhibited microvascular injury, which was manifested by gaps between endothelial cells, vascular occlusion, erythrocyte extravasation, or endothelial cell injury. In four patients, a variety of virus-like particles were found associated with the endothelium or perivascular cells. In two cases, particles were seen in electron-dense deposits in vessel walls. Lymphocytes and PMN infiltrated the synovial membranes, but plasma cells were uncommon. Evidence of phagocytosis was prominent in synovial lining cells and other large mononuclear cells, but not in PMN. These observations are consistent with injury to synovium and, specifically, synovial vessels as an early stage in RA synovitis. The virus-like particles require further investigation, because nonviral cell components remain very difficult to distinguish in electron microscopy tissue sections.
The complete nucleotide sequence of rna-2 genome segments of four isolates of Peanut clump virus (PCV) and two isolates of Indian peanut clump virus (IPCV) were determined. Comparisons among the complete rna-2 sequenc...
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The complete nucleotide sequence of rna-2 genome segments of four isolates of Peanut clump virus (PCV) and two isolates of Indian peanut clump virus (IPCV) were determined. Comparisons among the complete rna-2 sequences of six isolates from this study and two published earlier, revealed a high degree of variability in size (between 4290 and 4652 nucleotides) and nucleotide sequence identities (between 58% and 79%). Amino acid sequence alignments of the five open reading frames (ORF) showed that ORF 4, which encodes the second of the triple gene block proteins, is highly conserved (90 to 98% identical) whereas the protein encoded by ORF 2, whose function is unknown, is less conserved (25 to 60% identical). The coat protein of the eight isolates showed amino acid identities between 37% and 89% and contained several conserved residues. Phylogenetic comparisons, based on complete rna-2 sequences, revealed that the eight isolates grouped into two distinct clusters with no geographical distinction between PCV and IPCV isolates. Phylogenetic tree topologies for individual ORFs showed an overall similarity with that obtained from entire rna-2 sequences, although the relative positions of individual isolates vary within each cluster. The results indicate that there is substantial divergence among the rna-2 genomes of pecluviruses and suggest that different proteins have evolved differently, possibly due to different selection pressures.
Trichomonas vaginalis viruses (TVV), which may regulate P270 gene expression in the protozoan pathogen T: vaginalis, are a group of divergent double-stranded (ds) rna viruses. In the present study, the complete 4674-b...
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Trichomonas vaginalis viruses (TVV), which may regulate P270 gene expression in the protozoan pathogen T: vaginalis, are a group of divergent double-stranded (ds) rna viruses. In the present study, the complete 4674-bp cDNA sequence of a 4.6-kb ds rna from a newly identified TVV2-1 isolate was determined. The sequence of the plus-strand mrna contains four open reading frames, which encode overlapping cap and pol genes in the reading frame 2 and reading frame 1, respectively, and two putative serine-threonine-rich basic proteins VP3 and VP4 in the third reading frame. An 85-kDa capsid protein and a 180-kDa CAP-POL fusion protein were identified in crude viruses by Western blotting experiments using antisera raised against gene-specific oligopeptides. In conjunction with the presence of a potential ribosomal slippery heptanucleotide G GGC CCC within the overlap of the cap and pol genes, these observations suggest that the pol gene of TVV2-1 is translated via a -1 ribosomal frameshifting event during translation of the cap gene. Our results also provide insight into the conservation among divergent dsrna species from TW and suggest that the genome of TVV2-1 may encode two extra genes in addition to the cap and pol genes. (C) 2000 Academic Press.
Rice grassy stunt virus is a member of the genus Tenuivirus, is persistently transmitted by a brown planthopper, and has occurred in rice plants in South, Southeast, and East Asia (similar to North and South America)....
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Rice grassy stunt virus is a member of the genus Tenuivirus, is persistently transmitted by a brown planthopper, and has occurred in rice plants in South, Southeast, and East Asia (similar to North and South America). We determined the complete nucleotide (nt) sequences of rnas 1 (9760 nt), 2 (4069 nt), 3 (3127 nt), 4 (2909 nt), 5 (2704 nt), and 6 (2590 nt) of a southern Philippine isolate from South Cotabato and compared them with those of a northern Philippine isolate from Laguna (Toriyama et al., 1997 1998). The numbers of nucleotides in the terminal untranslated regions and open reading frames were identical between the two isolates except for the 5' untranslated region of the complementary strand of rna 4. Overall nucleotide differences between the two isolates were only 0.08% in rna 1, 0.58% in rna 4, and 0.26% in rna 5, whereas they were 2.19% in rna 2, 8.38% in rna 3, and 3.63% in rna 6. In the intergenic regions, the two isolates differed by 9.12% in rna 2, 11.6% in rna 3, and 6.86% in rna 6 with multiple consecutive nucleotide deletion/insertions, whereas they differed by only 0.78% in rna 4 and 0.34% in rna 5. The nucleotide variation in the intergenic region of rna 6 within the South Cotabato isolate was only 0.33%. These differences in accumulation of mutations among individual rna segments indicate that there was genetic reassortment in the two geographical isolates;rnas 1, 4, and 5 of the two isolates came from a common ancestor, whereas rnas 2, 3, and 6 were from two different ancestors. (C) 2000 Academic Press.
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