Figure 1.

High CO₂ associates with decrease of skeletal muscle ribosomal gene expression in humans. (A) Biopsies from quadriceps skeletal muscle of normocapnic (NC; n = 4) versus hypercapnic (HC; n = 3) patients were sampled, and quantitative PCR (qPCR) was performed to determine the expression level of 45S pre-RNA/GAPDH. **P < 0.01. (B) Different covariables present in both groups of patients. (No statistical analyses were performed to compare these variables, given the small number of patients in this pilot study.) BMI = body mass index; FEV₁ = forced exporatory volume in 1 second; FVC = forced vital capacity; pCO₂ = carbon dioxide tension; pO₂ = oxygen tension; Qcsa = quadriceps cross-sectional area; Qthick = quadriceps muscle thickness; Sat O₂ = arterial oxygen saturation.