On the question of the ultrastructure and composition of corpus intra cristam after local methylcholanthrene application

Increased intra-mitochondrial lipofuscin aggregates with spherical dense body formation in mitochondrial myopathy

Lipofuscin aggregation may result from incomplete degradation of damaged mitochondria by autophagy-lysosome pathway, and intra-mitochondrial lipofuscin aggregation may exacerbate mitochondrial abnormalities in mitochondrial myopathy (MM) and mitochondrial disease. We examined vastus lateralis muscle biopsies from 24 patients with pathologically diagnosed MM and clinically diagnosed chronic progressive external ophthalmoplegia, in comparison to the biopsies from 3 other groups:10 patients with inclusion body myositis (IBM), 11 younger adults, and 10 older subjects with no to minimal myopathic changes. Lipofuscin aggregation in muscle fibres was assessed on autofluorescence microscopy, some histochemical stains, and electron microscopy (EM). EM analyses demonstrated intra-mitochondrial lipofuscin aggregates, spherical dense bodies (SDBs), and paracrystalline inclusions (PCIs) which were semi-quantitatively assessed. Intra-mitochondrial lipofuscin aggregates showed no significant differences between groups of MM patients and older subjects or IBM patients, but significant differences between groups of younger adults and others with associated age-related changes. Intra-mitochondrial SDBs were significantly more in MM patients than in older subjects, IBM patients, and younger adults. There was a significant positive correlation between intra-mitochondrial lipofuscin aggregates and SDBs. These findings suggest that intra-mitochondrial formation of lipofuscin SDBs is more in MM and contributing to the pathophysiology of mitochondrial disease.

Sperm tail differentiation in the nudibranch mollusc Hypselodoris tricolor (Gastropoda, Opisthobranchia)

The sperm axoneme of Hypselodoris tricolor forms from a single centriole that is located initially beneath the plasma membrane and then migrates to the nuclear surface. A conspicuous centriolar adjunct-like formation is present in the neck of midspermatids, but it becomes very reduced at the end of spermiogenesis. In spermatocyte and spermatid mitochondria, intracristal bodies originate from the accumulation of a dense material in some cristae. From our observations and foregoing reports, it may be concluded that the process of sperm tail differentiation in opisthobranchs resembles that in pulmonates, whereas it differs in many respects from that occurring in prosobranchs. The appearance of intracristal bodies in modified mitochondria seems to be a special feature of spermatogenesis in the opisthobranchs that does not occur in the two other groups of gastropod molluscs.

[On the question of cutaneous changes associated with paraproteinemia. Light- and electron-microscopic study (author's transl)]

This report deals with a case of paraproteinemia (IgG Kappa) associated with skin indurations and yellowish papules on the trunk, edema of the face, and crystals in the cornea. In addition to the absence of elastic fibers and reductions of collagen fibers, light microscopy revealed single and/or multinucleated dermal cells with slight streaky patterning of the cytoplasm. These cells contained some sudanophilic (the greatest quantities of sudanophilic substances were observed in the deep corium) and partly birefringent material. In particular after warming, numerous spherocrystals appeared, which give Maltese cross birefringence. The presence of cholesterol esters can be assumed. The light-microscopic localization of acid phosphatase (incubation in Gomori medium) coincides in part with the distribution of bifringent lipids. Electron microscopy showed the cells with streaky contents to be chiefly histiocytes with numerous cristalline bodies in their cytoplasm. The cristalloids with a periodic inner structure are always surrounded by a single membrane. Identical bodies can be detected in endothelial cells of capillaries and epidermal keratinocytes. After pronase P incubation they disappear completely. We assume that the deposits correspond to phagocytized paraprotein. In addition, some histiocytic cells contain numerous lipid droplets in their cytoplasm. There is disintegration of some cells with crystalline inclusion, particularly in the deep corium. These cells show not only diffuse intracytoplasmic but also extracellular distribution of acid phosphatase activities. Particularly in the pericellular space of such cells numerous "banded structures" appear in connection with collagen degradation probably initiated by lysosomal enzymes. Amyloid could not be detected either light- or electron-microscopically.

Ultrastructural study of globular inclusions in human skeletal muscle mitochondria

Limb muscle biopsies from a patient with Luft's disease and a patient with a slowly progressive neuromuscular disorder since infancy revealed by conventional electron microscopy the presence of globular inclusions in the mitochondria as one of the most prominent morphological findings. Electron cytochemical studies on fresh tissue blocks showed no cytochrome c oxidase activity within the globular inclusions. The study of strontium uptake supported by either NAD and flavo-protein linked substrates in freshly isolated mitochondria fractions showed no electron-dense needles within the globular inclusions. Attempts to remove the inclusions with pepsin and with pronase on ultrathin sections failed but they were partially and totally removed by treatment of the sections with hydrogen peroxide. Freeze fracture studies showed the globular inclusions consisted of amorphous and lamellar material. The results suggest that the globular inclusions in muscle mitochondria may consist primarily of lipid.

Comparative ultrastructure and cytochemistry of epidermal responses to tape stripping, ethanol and vitamin A acid in hairless mice

The responses of hairless mouse epidermis to tape stripping, ethanol and vitamin A acid were compared using electron microscopy and cytochemistry. Stripping the skin 4 times with cellophane tape removed most of the stratum corneum and caused the development of enlarged intercellular spaces and dense intramitochondrial inclusions. These changes began within an hour, reached a maximum by 24 hr, and subsided by about 4 days. There was also some accumulation of glycogen and the development of occasional basal lamina breaks and a few intracellular lipid droplets by 24 hr. Topically applied ethanol (95%) produced a similar response, though less damaging. In addition, ethanol induced the formation of numerous lipid droplets in the cytoplasm of keratinocytes by 24 hr and often caused sloughing of the stratum corneum. Vitamin A acid (3%) was dissolved in propylene glycol for application to the skin. We found the application of propylene glycol alone to produce no epidermal changes. Vitamin A acid produced mild damaging effects with small intercellular spaces and intramitochondrial inclusions, but no lipid droplets or glycogen were detected. Vitamin A acid also caused dramatic inhibition of keratinization by 24 hr. Intramitochondrial inclusions were digested by protease, indicating a protein component and they also stained with silver methenamine, indicating the presence of glycogen or glycoprotein.