These are structural defects, acid phosphatase activity in muscle fibers, endomysial fibrosis, caliber variation, whorled fibers, internal nuclei and fiber splitting.
Large-caliber fiber reduction and formation of isolated monostratified "simple onion bulbs" have been described in CMT2 [3].
In transverse sections of fresh frozen specimens from the triceps brachii, tibialis anterior and vastus lateralis muscles, there was a marked variability in myofiber size in the treated double transgenic animals, with numerous small caliber fibers having a round shape, and multifocal clusters of mononuclear cells.
Males, on the other hand, had higher AD in the right superior longitudinal fasciculus, right inferior longitudinal fasciculus, and forceps minor, which may reflect a restriction of diffusion along these association fibers while axonal caliber increases.
Strong gelatinase activity was detected in the endomysium not only of fibers with infiltration of CD11b positive cells (Fig. 2A,B,C), but also of MHCd-positive, small caliber, centronuclear fibers (Fig. 2E,F,G), which represent degenerating and regenerating fibers, respectively.
As can be seen in Fig. 12a and b, large caliber axonal fibers are evident in the LBC1936 and AD tissue and these are tightly wrapped in high density myelin.
In contrast to skeletal muscle, where the loss of plectin causes massive aggregation of desmin IFs (Konieczny et al. 2008), in myelinating Schwann cells, the impact of plectin deficiency on the organization of the vimentin IF system was detectable just as a decrease in the vimentin IF network density in a fraction of nerve fibers characterized by large caliber axons (Walko et al. 2013).
The small-caliber fibers of the PMB are selectively lost in a very early stage of the pathologic process.
Plastic-embedded sections of the biopsy specimen showed features of active axonal neuropathy with decreased density of myelinated fibers of all calibers, ongoing wallerian-like degeneration and sporadic small clusters of regenerating fibers, in the absence of cellular inflammation.
We believe that during repair the only function of collagen fibrils is to contain the stromal content since the tissue is not submitted to important functional alterations that require the deposition of fibers with variable calibers.
