Background and aims Overall obesity has recently been established as an independent risk factor for critical illness in patients with coronavirus disease 2019 (COVID-19). The role of fat distribution and especially that of visceral fat, which is often associated with metabolic syndrome, remains unclear. Therefore, this study aims at investigating the association between fat distribution and COVID-19 severity. Methods Thirty patients with COVID-19 and a mean age of 65.6 ± 13.1 years from a level-one medical center in Berlin, Germany, were included in the present cross-sectional analysis. COVID-19 was confirmed by polymerase chain reaction (PCR) from nasal and throat swabs. A severe clinical course of COVID-19 was defined by hospitalization in the intensive care unit (ICU) and/or invasive mechanical ventilation. Fat was measured at the level of the first lumbar vertebra on routinely acquired low-dose chest computed tomography (CT). Results An increase in visceral fat area (VFA) by ten square centimeters was associated with a 1.37-fold higher likelihood of ICU treatment and a 1.32-fold higher likelihood of mechanical ventilation (adjusted for age and sex). For upper abdominal circumference, each additional centimeter of circumference was associated with a 1.13-fold higher likelihood of ICU treatment and a 1.25-fold higher likelihood of mechanical ventilation. Conclusions Our proof-of-concept study suggests that visceral adipose tissue and upper abdominal circumference specifically increase the likelihood of COVID-19 severity. CT-based quantification of visceral adipose tissue and upper abdominal circumference in routine chest CTs may therefore be a simple tool for risk assessment in COVID-19 patients.

The synthesis of picornavirus polyproteins is initiated cap independently far downstream from the 5 end of the viral RNA at the internal ribosome entry site (IRES). The cellular polypyrimidine tract-binding protein (PTB) binds to the IRES of foot-and-mouth disease virus (FMDV). In this study, we demonstrate that PTB is a component of 48S and 80S ribosomal initiation complexes formed with FMDV IRES RNA. The incorporation of PTB into these initiation complexes is dependent on the entry of the IRES RNA, since PTB and IRES RNA can be enriched in parallel either in 48S or 80S ribosomal complexes by stage-specific inhibitors of translation initiation. The formation of the ribosomal initiation complexes with the IRES occurs slowly, is temperature dependent, and correlates with the incorporation of PTB into these complexes. In a first step, PTB binds to the IRES, and then the small ribosomal subunit encounters this PTB-IRES complex. Mutations in the major PTB-binding site interfere simultaneously with the formation of initiation complexes, translation efficiency, and PTB cross-linking. PTB stimulates translation directed by the FMDV IRES in a rabbit reticulocyte lysate depleted of internal PTB, and the efficiency of translation can be restored to the original level by the addition of PTB. These results indicate that PTB plays an important role in the formation of initiation complexes with FMDV IRES RNA and in stimulation of internal translation initiation with this picornavirus.

We studied the interaction of cellular proteins with the internal ribosome entry site (IRES) of foot-andmouth disease virus by UV cross-linking and observed specific binding of a 80-kDa protein contained in cytosolic HeLa cell extract and in rabbit reticulocyte lysate. Binding of the protein was dependent on the presence of ATP. Immunoprecipitation with eIF-4B antiserum revealed that the protein is identical to the initiation factor eIF-4B. Deletions in the 3 part, but not in the 5 part, of the IRES interfered with UV cross-linking, indicating that the binding site of eIF-4B is located close to the end of the element. Attempts to separate ribosome-associated from non-ribosome-associated protein fractions of cytosolic cell extracts led to the loss of cross-linking activity. This finding suggests that additional protein factors contribute to this interaction of eIF-4B with the IRES of foot-and-mouth disease virus.on July 10, 2020 by guest http://jvi.asm.org/ Downloaded from strate for the first time the direct interaction of initiation factor eIF-4B with the IRES element of FMDV. MATERIALS AND METHODSPlasmids. The construction of pSP449, containing the complete IRES element and the first translational initiation site of FMDV O 1 K (positions 363 to 832), inserted into pSP65 (26), has been described previously (23). Plasmids pSP449, pSP449⌬2, pSP449⌬3, pSP449⌬4, pSP449⌬2,3, and pSP449⌬2,4, carrying single or double deletions of predicted stem-loop structures of the IRES element (37), were derived from plasmid pSP449 by site-directed mutagenesis using the M13 system (17) and will be described elsewhere (36a). Plasmid pSPnon contains the nucleotide sequence of FMDV from positions 2730 to 3000, in inverted orientation, inserted into a derivative of pSP65. Plasmid pGEM2-2␤ is a complete cDNA clone of the ␤ subunit of eIF-2␤ (31), plasmid pS32A3 contains the 5Ј noncoding region of ECMV (14), and plasmid pT7-XLmyr Ϫ contains the 5Ј noncoding region of poliovirus (16).RNA substrates. Plasmids pSP449, pSP449⌬2, pSP449⌬3, pSP449⌬4, pSP449⌬2,3 and pSP449⌬2,4 were each linearized with SmaI, plasmid pSPnon was cleaved with SacI, and plasmid pGEM2-2␤ was cleaved with BfrI. The plasmids were transcribed in vitro by using SP6 RNA polymerase (Promega Corp.) essentially as described previously (26). Labelled RNAs were derived in the presence of 2.5 M [␣-32 P]CTP (400 Ci/mmol; Amersham Corp.). In vitro transcripts from linearized plasmids pS32A3 and pT7-XLmyr Ϫ were derived analogously with T7 RNA polymerase as described previously (44). Reaction mixtures were treated with RNase-free DNase I (Boehringer Mannheim) and separated from unincorporated nucleotides by gel filtration on Sephadex G-50 (Pharmacia).Cell extracts. Cell lysates were prepared either by mechanical shock using the method described by Nygård et al. (30) or by osmotic shock (5). For the latter, HeLa S3 cells were harvested from suspension cultures at 10 6 cells per ml by centrifugation, washed twice with phosphate-buffered saline (PBS; 8 mM Na 2 HPO 4 -NaH 2 PO 4 [pH...

Purpose Emphysema and chronic obstructive lung disease were previously identified as major risk factors for severe disease progression in COVID-19. Computed tomography (CT)-based lung-density analysis offers a fast, reliable, and quantitative assessment of lung density. Therefore, we aimed to assess the benefit of CT-based lung density measurements to predict possible severe disease progression in COVID-19. Material and methods Thirty COVID-19-positive patients were included in this retrospective study. Lung density was quantified based on routinely acquired chest CTs. Presence of COVID-19 was confirmed by reverse transcription polymerase chain reaction (RT-PCR). Wilcoxon test was used to compare two groups of patients. A multivariate regression analysis, adjusted for age and sex, was employed to model the relative increase of risk for severe disease, depending on the measured densities. Results Intensive care unit (ICU) patients or patients requiring mechanical ventilation showed a lower proportion of medium- and low-density lung volume compared to patients on the normal ward, but a significantly larger volume of high-density lung volume (12.26 dl IQR 4.65 dl vs. 7.51 dl vs. IQR 5.39 dl, p = 0.039). In multivariate regression analysis, high-density lung volume was identified as a significant predictor of severe disease. Conclusions The amount of high-density lung tissue showed a significant association with severe COVID-19, with odds ratios of 1.42 (95% CI: 1.09-2.00) and 1.37 (95% CI: 1.03-2.11) for requiring intensive care and mechanical ventilation, respectively. Acknowledging our small sample size as an important limitation; our study might thus suggest that high-density lung tissue could serve as a possible predictor of severe COVID-19.

INTRODUCTION: During the unprecedented health crisis of the COVID-19 pandemic it was suggested that obesity might aggravate severe acute respiratory syndrome coronavirus-2 (SARS CoV-2). Therefore, this study aims to investigate the association between Compute Tomography (CT)-based measurements of visceral and subcutaneous fat as measures of obesity and COVID-19 severity. METHODS: 30 patients with laboratory-confirmed COVID-19 and a mean age of 65.59 plus/minus 13.06 years from a level one medical center in Berlin, Germany, were retrospectively analyzed and included in the present analysis. SARS-CoV-2 was confirmed by polymerase chain reaction from throat swaps or deep nasal swabs on the day of admission. Severe clinical courses of COVID-19 were defined by hospitalization in intensive care unit (ICU) and invasive mechanical ventilation. All patients received low-dose chest CT-based fat measurements at the level of the first lumbar vertebra. RESULTS: An increase in visceral fat area (VFA) by one square decimeter was associated with a 22.53-fold increased risk for ICU treatment and a 16.11-fold increased risk for mechanical ventilation (adjusted for age and sex). For upper abdominal circumference, each additional centimeter of circumference showed a 1.13-fold increased risk for ICU treatment and a 1.25-fold increased risk for mechanical ventilation. There was no significant correlation of subcutaneous fat area (SFA) or body mass index (BMI) with severe clinical courses of COVID-19. CONCLUSIONS: Our results suggest that visceral adipose tissue and upper abdominal circumference specifically increasing the risk of COVID-19 severity. CT-based quantification of visceral adipose tissue and upper abdominal circumference in routinely acquired chest CTs may therefore be a simple tool for risk assessment in SARS-CoV-2-patients.