Impaired muscle strength is associated with ultrastructure damage in myositis.

The muscle fiber ultrastructure in Idiopathic Inflammatory Myopathies (IIM) has been scarcely explored, especially in Inclusion Body Myositis. The aim of this study was to implement the Scanning Electron Microscopy (SEM) in a small cohort of IIM patients, together with the characterization of immunological profile for a better understanding of the pathophysiology. For immunological profile characterization, we identified the presence of autoantibodies (Ro-52, OJ, EJ, PL7, PL12, SRP, Jo-1, PMScl75, PMScl100, Ku, SAE1, NXP2, MDA5, TIF1γ, Mi-2α, Mi-2ß) and quantified cytokines (IL-1ß, IFN-α2, IFN-γ, TNF-α, IL-6, IL-10, IL-12p70, IL-17A, IL-18, IL-23, IL-33) and chemokines (CCL2, CXCL8). The histological analysis was made by hematoxylin-eosin staining while the muscle fiber ultrastructure was characterized by SEM. We observed changes in the morphology and structure of the muscle fiber according to muscle strength and muscle enzymes. We were able to find and describe muscle fiber ultrastructure with marked irregularities, porosities, disruption in the linearity and integrity of the fascicle, more evident in patients with increased serum levels of muscle enzymes and diminished muscle strength. Despite the scarce reports about the use of SEM as a tool in all clinical phenotypes of IIM, our work provides an excellent opportunity to discuss and reframe the clinical usefulness of SEM in the diagnostic approach of IIM.

Noninvasive determination of burn depth in children by digital infrared thermal imaging.

Digital infrared thermal imaging is used to assess noninvasively the severity of burn wounds in 13 pediatric patients. A delta-T (ΔT) parameter obtained by subtracting the temperature of a healthy contralateral region from the temperature of the burn wound is compared with the burn depth measured histopathologically. Thermal imaging results show that superficial dermal burns (IIa) show increased temperature compared with their contralateral healthy region, while deep dermal burns (IIb) show a lower temperature than their contralateral healthy region. This difference in temperature is statistically significant (p<0.0001) and provides a way of distinguishing deep dermal from superficial dermal burns. These results show that digital infrared thermal imaging could be used as a noninvasive procedure to assess burn wounds. An additional advantage of using thermal imaging, which can image a large skin surface area, is that it can be used to identify regions with different burn depths and estimate the size of the grafts needed for deep dermal burns.