Purpose To evaluate three coronary artery calcification (CAC) scoring methods to assess risk of coronary heart disease (CHD) death and all-cause mortality in National Lung Screening Trial (NLST) participants across levels of CAC scores. Materials and Methods The NLST was approved by the institutional review board at each participating institution, and informed consent was obtained from all participants. Image review was HIPAA compliant. Five cardiothoracic radiologists evaluated 1575 low-dose computed tomographic (CT) scans from three groups: 210 CHD deaths, 315 deaths not from CHD, and 1050 participants who were alive at conclusion of the trial. Radiologists used three scoring methods: overall visual assessment, segmented vessel-specific scoring, and Agatston scoring. Weighted Cox proportional hazards models were fit to evaluate the association between scoring methods and outcomes. Results In multivariate analysis of time to CHD death, Agatston scores of 1–100, 101–1000, and greater than 1000 (reference category 0) were associated with hazard ratios of 1.27 (95% confidence interval: 0.69, 2.53), 3.57 (95% confidence interval: 2.14, 7.48), and 6.63 (95% confidence interval: 3.57, 14.97), respectively; hazard ratios for summed segmented vessel-specific scores of 1–5, 6–11, and 12–30 (reference category 0) were 1.72 (95% confidence interval: 1.05, 3.34), 5.11 (95% confidence interval: 2.92, 10.94), and 6.10 (95% confidence interval: 3.19, 14.05), respectively; and hazard ratios for overall visual assessment of mild, moderate, or heavy (reference category none) were 2.09 (95% confidence interval: 1.30, 4.16), 3.86 (95% confidence interval: 2.02, 8.20), and 6.95 (95% confidence interval: 3.73, 15.67), respectively. Conclusion By using low-dose CT performed for lung cancer screening in older, heavy smokers, a simple visual assessment of CAC can be generated for risk assessment of CHD death and all-cause mortality, which is comparable to Agatston scoring and strongly associated with outcome.
We report here the discovery of a small molecule inhibitor of pestivirus replication. The compound, designated VP32947, inhibits the replication of bovine viral diarrhea virus (BVDV) in cell culture at a 50% inhibitory concentration of approximately 20 nM. VP32947 inhibits both cytopathic and noncytopathic pestiviruses, including isolates of BVDV-1, BVDV-2, border disease virus, and classical swine fever virus. However, the compound shows no activity against viruses from unrelated virus groups. Time of drug addition studies indicated that VP32947 acts after virus adsorption and penetration and before virus assembly and release. Analysis of viral macromolecular synthesis showed VP32947 had no effect on viral protein synthesis or polyprotein processing but did inhibit viral RNA synthesis. To identify the molecular target of VP32947, we isolated drug-resistant (DR) variants of BVDV-1 in cell culture. Sequence analysis of the complete genomic RNA of two DR variants revealed a single common amino acid change located within the coding region of the NS5B protein, the viral RNAdependent RNA polymerase. When this single amino acid change was introduced into an infectious clone of drug-sensitive wild-type (WT) BVDV-1, replication of the resulting virus was resistant to VP32947. The RNA-dependent RNA polymerase activity of the NS5B proteins derived from WT and DR viruses expressed and purified from recombinant baculovirus-infected insect cells confirmed the drug sensitivity of the WT enzyme and the drug resistance of the DR enzyme. This work formally validates NS5B as a target for antiviral drug discovery and development. The utility of VP32947 and similar compounds for the control of pestivirus diseases, and for hepatitis C virus drug discovery efforts, is discussed. P estivirus infections of domesticated livestock (cattle, pigs, and sheep) cause significant economic losses worldwide, as exemplified by recent disease outbreaks in the U.S., Canada, The Netherlands, and Germany (1-7). Bovine viral diarrhea virus (BVDV), the prototypic representative of the pestivirus genus, family Flaviviridae, is ubiquitous and causes a range of clinical manifestations, including abortion, teratogenesis, respiratory problems, chronic wasting disease, immune system dysfunction, and predisposition to secondary viral and bacterial infections (8). Certain BVDV strains can cause acute fatal disease with mortality rates of 17-32% (1, 9, 10). BVDV is also able to establish persistent infections in fetuses (11,12). When born, these persistently infected animals remain viremic throughout life and serve as continuous sources for virus spread in herds. Persistently infected animals may also succumb to fatal mucosal disease on superinfection with closely related BVDV strains. Vaccines are used in some countries in an attempt to control pestivirus disease with varying degrees of success (8, 13). In other countries, animal culling, quarantine, and slaughter are used to contain pestivirus disease outbreaks (2). Currently, there are no antiviral pharmaceu...
In renal transplant recipients, chronic hepatitis B virus (HBV) infection often leads to cirrhosis and liver failure. In this study, we investigated whether or not in these patients viral variants would emerge despite immunosuppression, and whether they are associated with a specific course of liver disease. In a population of 552 renal transplant recipients hepatitis B 24 surface antigen (HBsAg)-positive patients were available for a 2-year follow-up. By polymerase chain reaction (PCR) and DNA sequencing, HBV genomes with deletions in the middle of the core gene (C-gene) were found in 9 out of the 24 patients. Seven of the 9 patients (group I) showed either persistent or increasing amounts of these variants; all patients had cirrhosis, and 5 died of end-stage liver disease. The viral variants emerged at least 1 year before liver failure. In 2 out of the 9 patients, the core deletion variants disappeared, and no further deterioration of the liver function was observed thereafter. In the remaining 15 patients (group II) without deletion mutants detected at any time, only 3 had cirrhosis (P < .001, group I vs. II), and none died (P < .001). Between both groups, there were no statistically significant differences in the other relevant variables that were examined. These results indicate that HBV C-gene deletion mutants can accumulate in long-term immunosuppressed patients, and that their persistence is associated with progressive liver disease. The accumulation of these variants may be caused by the development of cirrhosis or could be involved in hepatopathogenesis.
The metrics of FOR, LIRS, and the product of the two metrics provided the highest agreement in motion artifact ranking when compared to the readers, and the highest linear correlation to the reader scores. The validated motion artifact metrics may be useful for developing and evaluating methods to reduce motion in Coronary Computed Tomography Angiography (CCTA) images.
An internal ribosome entry site (IRES) mediates translation initiation of bovine viral diarrhea virus (BVDV) RNA. Studies have suggested that a portion of the Npro open reading frame (ORF) is required, although its exact function has not been defined. Here we show that a subgenomic (sg) BVDV RNA in which the NS3 ORF is preceded only by the 5 nontranslated region did not replicate to detectable levels following transfection. However, RNA synthesis and cytopathic effects were observed following serial passage in the presence of a noncytopathic helper virus. Five sg clones derived from the passaged virus contained an identical, silent substitution near the beginning of the NS3 coding sequence (G400U), as well as additional mutations. Four of the reconstructed mutant RNAs replicated in transfected cells, and in vitro translation showed increased levels of NS3 for the mutant RNAs compared to that of wild-type (wt) MetNS3. To more precisely dissect the role of these mutations, we constructed two sg derivatives: ad3.10, which contains only the G400U mutation, and ad3.7, with silent substitutions designed to minimize RNA secondary structure downstream of the initiator AUG. Both RNAs replicated and were translated in vitro to similar levels. Moreover, ad3.7 and ad3.10, but not wt MetNS3, formed toeprints downstream of the initiator AUG codon in an assay for detecting the binding of 40S ribosomal subunits and 43S ribosomal complexes to the IRES. These results suggest that a lack of stable RNA secondary structure(s), rather than a specific RNA sequence, immediately downstream of the initiator AUG is important for optimal translation initiation of pestivirus RNAs.The pestiviruses are animal pathogens causing acute, chronic, and persistent infections that can result in substantial economic losses in the livestock industry (22,31,41). Members include bovine viral diarrhea virus (BVDV), classical swine fever virus (CSFV), border disease virus, and the newly proposed member, BVDV-2 (4). The pestiviruses are grouped in the Flaviviridae family along with the hepaciviruses (hepatitis C viruses [HCVs]) and classical flaviviruses; however, similarities in genome organization, translation initiation strategy, and polyprotein processing suggest that the pestiviruses and HCVs are more closely related to each other than to the classical flaviviruses.The Flaviviridae are small, enveloped viruses containing a single-stranded positive-sense RNA genome (31). The genomes are usually between 9.5 and 12.5 kb in length, with 5Ј and 3Ј nontranslated regions (NTRs) flanking one long open reading frame (ORF), and lack the 3Ј poly(A) tract. Translation of the viral RNA yields a single polyprotein that is co-and posttranslationally processed by host and viral proteases. The classical flaviviruses contain a type 1 cap at the 5Ј end that directs translation initiation in a cap-dependent manner. In contrast, the 5Ј NTRs of the pestiviruses and HCVs contain structurally and functionally similar internal ribosome entry site (IRES) elements that mediate t...
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