Effect of anticipation triggered by a prior dyspnea experience on brain activity.

[Purpose] Oxygenated hemoglobin (oxy-Hb) concentrations in the prefrontal cortex are closely associated with dyspnea. Dyspnea is influenced not only by physical activity, but also by visual stimuli, and several studies suggest that oxy-Hb concentrations change in response to certain external stimuli. However, the effects of internal psychological states on dyspnea have not been reported. This study explored the influence of anticipation triggered by previous episodes of dyspnea on brain activity. [Subjects] The subjects were 15 healthy volunteers with a mean age of 25.0 ± 3.0 years. [Methods] The subjects were shown a variety of photographs and instructed to expect breathing resistance matched to the affective nature of the particular photograph. After viewing the images, varying intensities of breathing resistance that were identical to, easier than, or harder than those shown in the images were randomly administered to the subjects; in fact, the image and resistance were identical 33% of the time and discordant 66% of the time. [Results] The concentrations of oxy-Hb in the right medial prefrontal cortex (rMPFC) increased significantly with an inspiratory pressure that was 30% of the maximum intensity in the subjects shown a pleasant image compared to the concentrations in subjects shown an unpleasant image. Moreover, rMPFC activity was significantly correlated with the magnitude of the dyspnea experienced. [Conclusion] These results suggest that a correlation exists between increased oxy-Hb in the rMPFC and the effects of expectations on dyspnea.

Electrical stimulation mitigates muscle degradation shift in gene expressions during 12-h mechanical ventilation.

Ventilator-induced diaphragm dysfunction (VIDD), a dysfunction of the diaphragm muscle caused by prolonged mechanical ventilation (MV), is an important factor that hinders successful weaning from ventilation. We evaluated the effects of electrical stimulation of the diaphragm muscle (pulsed current with off-time intervals) on genetic changes during 12 h of MV (E-V12). Rats were divided into four groups: control, 12-h MV, sham operation, and E-V12 groups. Transcriptome analysis using an RNA microarray revealed that 12-h MV caused upregulation of genes promoting muscle atrophy and downregulation of genes facilitating muscle synthesis, suggesting that 12-h MV is a reasonable method for establishing a VIDD rat model. Of the genes upregulated by 12-h MV, 18 genes were not affected by the sham operation but were downregulated by E-V12. These included genes related to catabolic processes, inflammatory cytokines, and skeletal muscle homeostasis. Of the genes downregulated by 12-h MV, 6 genes were not affected by the sham operation but were upregulated by E-V12. These included genes related to oxygen transport and mitochondrial respiration. These results suggested that 12-h MV shifted gene expression in the diaphragm muscle toward muscle degradation and that electrical stimulation counteracted this shift by suppressing catabolic processes and increasing mitochondrial respiration.

Quantitative assessment of hand radiographs of rheumatoid arthritis: interobserver variation in a multicenter radiographic study.

We investigated interobserver variations in the Larsen radiographic scoring method on hand radiographs of rheumatoid arthritis (RA) patients in a multicenter trial and developed a new radiographic scoring method. Thirteen experienced rheumatologists scored 10 representative RA hand radiograms with the Larsen scoring method and clarified the precipitating factors of interobserver variation. Based on this study, it was proved that the ankylotic joint, overlapping joint, and more precise erosive joint are needed for optimal radiographic evaluation. Therefore, we modified the Larsen scoring method on the basis of these precipitating factors and developed a novel radiographic scoring method. Finally, to determine which scoring system was most reliable, the interobserver variation using three methods (original Larsen method, revised Larsen method, our scoring method) were compared by 13 experienced rheumatologists and 13 residents. Our scoring method proved to have simplicity, reliability, and ease of learning. These results suggest that our novel radiological quantitative assessment method has useful applications for clinical studies in patients with RA.