Cryo-EM reveals a previously unrecognized structural protein of a dsRNA virus implicated in its extracellular transmission.

Mosquito viruses cause unpredictable outbreaks of disease. Recently, several unassigned viruses isolated from mosquitoes, including the Omono River virus (OmRV), were identified as totivirus-like viruses, with features similar to those of the Totiviridae family. Most reported members of this family infect fungi or protozoans and lack an extracellular life cycle stage. Here, we identified a new strain of OmRV and determined high-resolution structures for this virus using single-particle cryo-electron microscopy. The structures feature an unexpected protrusion at the five-fold vertex of the capsid. Disassociation of the protrusion could result in several conformational changes in the major capsid. All these structures, together with some biological results, suggest the protrusions' associations with the extracellular transmission of OmRV.

Interrater reliability and radiation dosage of oblique coronal computed tomography for sacroiliitis in comparison with axial computed tomography.

OBJECTIVE: Sacroiliitis, a prerequisite to the diagnosis of ankylosing spondylitis, can be ascertained by CT when MRI is not available. Oblique coronal CT is an increasingly popular approach when examining sacroiliitis. The goal of this study was to understand how oblique coronal CT compared with axial CT scanning in terms of raters' concordance when diagnosing sacroiliitis. METHODS: 52 subjects < 45 years of age at onset of their chronic lower back pain were sequentially scanned by X-ray, axial CT and oblique coronal CT. The acquired images were graded by two experienced, double-blinded physicians. RESULTS: Sacroiliitis in the oblique coronal view was sensitive enough for grading disease severity and/or detecting improvement. Interrater reliability for CT (axial + oblique coronal) was higher than X-ray. The diagnosis based upon oblique coronal CT was consistent, while the radiation dose delivered to the gonads was significantly reduced, compared with axial CT. CONCLUSION: When MRI is not available, oblique coronal CT should replace axial CT when diagnosing sacroiliitis. Advances in knowledge: When evaluating sacroiliitis, oblique coronal CT is as accurate as conventional axial CT, yet more advantageous owing to reduced radiation dosage.

Chikungunya outbreak in Guangdong Province, China, 2010.

A disease outbreak with dengue-like symptoms was reported in Guangdong Province, China, in October 2010. Testing results confirmed that the pathogen causing the outbreak was chikungunya virus. Phylogenic analysis indicated that this virus was a member of the Indian Ocean clade of the East/Center/South African subgroup of chikungunya virus.

[Parthenolide inhibits tumor necrosis factor-alpha induced catabolism of aggrecan in chondrocytes in osteoarthritis: in vitro experiment with cultured human chondrocytes].

OBJECTIVE: To investigate the effect of parthenolide (PAR) on the tumor necrosis factor (TNF)-alpha induced aggrecan catabolism of chondrocytes in osteoarthritis (OA). METHODS: Human chondrocytes were obtained from the condyles of femur of OA patients undergoing knee joint replacement during operation, cultured, and randomly divided into 4 groups: control group, TNF group (cultured in medium containing 10 ng/ml TNF-alpha) , PAR group (cultured in medium containing 10 micromol/L PAR), and PAR + TNF group (cultured in medium containing 10 micromol/L PAR and 10 ng/ml TNF-alpha). Eight days later 1, 9-dimethylmethylene blue spectrophotometric assay was used to measure the content of glycosaminoglycan (GAG) , marker of aggrecan catabolism, in the culture fluid and the cells. Using anti-aggrecan monoclonal antibodies Mab 5D4 and 3B3, ELISA was employed to detect the contents of 5D4 and 3B3, aggrecan catabolic fragments. RT-PCR was used to detect the mRNA expression of the aggrecan, ADAMTS-4 and ADAMTS-5, both aggrecanases, tissue inhibitor of metalloprotease (TIMP)-1, mitogen-activated protein kinase (MAPK)-1 and 18S, a marker. RESULTS: The GAG percentage in the culture fluid of the TNF-alpha was 57.1% +/- 2.0%, significantly higher than those of the control and TNF-alpha + PAR groups (P = 0.001 and 0.02). The 5D4 fragment level of the TNF-alpha group was 509 ng/ml +/- 32 ng/ml, significantly higher than that of the control group (166 ng/ml +/- 15 ng/ml, t = 11.60, P =0.007), and the level of 5D4 fragment of the PAR + TNF-alpha group was 333 ng/ml +/- 15 ng/ml, significantly lower than that of the TNF-alpha group (t = 7.93, P = 0.016). There was not significant difference in the 3B3 fragment level among the 4 groups (F = 1.316, P = 0.335). The aggrecan mRNA expression level of the TNF-alpha group was significantly lower than those of the other 3 groups (F = 133.7, P = 0.000), the mRNA expression levels of ADAMTS-5 and MAPK-1 of the TNF-alpha group were significantly higher than those of the other 3 groups (F = 209. 7, 117.1; P =0. 000), the ADAMTS-5 mRNA expression level of the PAR group was significantly lower than that of the control group (t = 11.1, P= 0.008) , and there was not significant differences in the mRNA expression levels of ADAMTS-4 and TIMP-1 among the 4 groups (F = 1.87, 0.73; P > 0.05) . CONCLUSION: PAR inhibits TNF-alpha induced catabolism of aggrecan in the chondrocytes of OA and reduces the mRNA expression of ADAMTS-5 and MAPK-1. PAR may be useful in the treatment of OA and other inflammatory joint diseases.

Cross-host evolution of severe acute respiratory syndrome coronavirus in palm civet and human.

The genomic sequences of severe acute respiratory syndrome coronaviruses from human and palm civet of the 2003/2004 outbreak in the city of Guangzhou, China, were nearly identical. Phylogenetic analysis suggested an independent viral invasion from animal to human in this new episode. Combining all existing data but excluding singletons, we identified 202 single-nucleotide variations. Among them, 17 are polymorphic in palm civets only. The ratio of nonsynonymous/synonymous nucleotide substitution in palm civets collected 1 yr apart from different geographic locations is very high, suggesting a rapid evolving process of viral proteins in civet as well, much like their adaptation in the human host in the early 2002-2003 epidemic. Major genetic variations in some critical genes, particularly the Spike gene, seemed essential for the transition from animal-to-human transmission to human-to-human transmission, which eventually caused the first severe acute respiratory syndrome outbreak of 2002/2003.