An Oscillatory Contractile Pole-Force Component Dominates the Traction Forces Exerted by Migrating Amoeboid Cells

We used principal component analysis to dissect the mechanics of chemotaxis of amoeboid cells into a reduced set of dominant components of cellular traction forces and shape changes. The dominant traction force component in wild-type cells accounted for ~40% of the mechanical work performed by these cells, and consisted of the cell attaching at front and back contracting the substrate towards its centroid (pole-force). The time evolution of this pole-force component was responsible for the periodic variations of cell length and strain energy that the cells underwent during migration. We identified four additional canonical components, reproducible from cell to cell, overall accounting for an additional ~20% of mechanical work, and associated with events such as lateral protrusion of pseudopodia. We analyzed mutant strains with contractility defects to quantify the role that non-muscle Myosin II (MyoII) plays in amoeboid motility. In MyoII essential light chain null cells the polar-force component remained dominant. On the other hand, MyoII heavy chain null cells exhibited a different dominant traction force component, with a marked increase in lateral contractile forces, suggesting that cortical contractility and/or enhanced lateral adhesions are important for motility in this cell line. By compressing the mechanics of chemotaxing cells into a reduced set of temporally-resolved degrees of freedom, the present study may contribute to refined models of cell migration that incorporate cell-substrate interactions

COVID-19 symptoms and SARS-CoV-2 infection among people living with HIV in the US: the MACS/WIHS combined cohort study

Background: SARS-CoV-2 infection among People Living With HIV (PLWH) is not well-described. Objective: To study COVID-19 symptoms and SARS-CoV-2 PCR-based swab testing among participants of the Multicenter AIDS Cohort Study (MACS) and Women’s Interagency HIV Study (WIHS). Methods: A telephone survey was collected April-June 30, 2020. Symptom and testing prevalence were explored. Multivariable logistic regression was used to examine the factors associated with SARS-CoV-2 positivity. Results: The survey was completed by 3411 participants, including 2078 (61%) PLWH and 1333 HIV-seronegative (SN) participants from across the US. Thirteen percent (n = 441) were tested for SARS-CoV-2 infection (13.4% of PLWH vs 12.2% of SN). Among those tested, positivity was higher in PLWH than SN (11.2% vs 6.1%, p = 0.08). Reasons for not being tested included testing not being available (30% of participants) and not knowing where to get tested (16% of participants). Most symptoms reported since January 2020 were similar in PLWH and SN, including headache (23% vs. 24%), myalgias (19% vs 18%), shortness of breath (14% vs 13%), chills (12% vs 10%), fever (6% vs 6%) and loss of taste or smell (6% vs 7%). Among PLWH who tested positive for SARS-CoV-2 DNA, the most common symptoms were headache (71%), myalgia (68%), cough (68%) and chills (65%). In multivariable analysis among those tested, the odds of SARS-CoV-2 positivity were higher among PLWH than SN (aOR = 2.22 95%CI = 01.01–4.85, p = 0.046) and among those living with others versus living alone (aOR = 2.95 95%CI = 1.18–7.40). Conclusion: Prevalence and type of COVID-19 symptoms were similar in PLWH and SN. SARS-CoV-2 infection may be elevated among PLWH

The External Genitalia Score (EGS): A European Multicenter Validation Study

CONTEXT: Standardized description of external genitalia is needed in the assessment of children with atypical genitalia. OBJECTIVES: To validate the External Genitalia Score (EGS), to present reference values for preterm and term babies up to 24 months and correlate obtained scores with anogenital distances (AGDs). DESIGN, SETTING: A European multicenter (n = 8) validation study was conducted from July 2016 to July 2018. PATIENTS AND METHODS: EGS is based on the external masculinization score but uses a gradual scale from female to male (range, 0-12) and terminology appropriate for both sexes. The reliability of EGS and AGDs was determined by the interclass correlation coefficient (ICC). Cross-sectional data were obtained in 686 term babies (0-24 months) and 181 preterm babies, and 111 babies with atypical genitalia. RESULTS: The ICC of EGS in typical and atypical genitalia is excellent and good, respectively. Median EGS (10th to 90th centile) in males < 28 weeks gestation is 10 (8.6-11.5); in males 28-32 weeks 11.5 (9.2-12); in males 33-36 weeks 11.5 (10.5-12) and in full-term males 12 (10.5-12). In all female babies, EGS is 0 (0-0). The mean (SD) lower/upper AGD ratio (AGDl/u) is 0.45 (0.1), with significant difference between AGDl/u in males 0.49 (0.1) and females 0.39 (0.1) and intermediate values in differences of sex development (DSDs) 0.43 (0.1). The AGDl/u correlates with EGS in males with typical genitalia and in atypical genitalia. CONCLUSIONS: EGS is a reliable and valid tool to describe external genitalia in premature and term babies up to 24 months. EGS correlates with AGDl/u in males. It facilitates standardized assessment, clinical decision-making and multicenter research

Induction by IL 1 and interferon-gamma: tissue distribution, biochemistry, and function of a natural adherence molecule (ICAM-1). J. Immunol. 1986. 137: 245-254.

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Damage identification of structural members: Numerical and experimental studies

10.1177/147592103031112Structural Health Monitoring2141-5