[Mitochondrial changes of the skeletal muscle in the peroneal muscular atrophy (Charcot-Marie-Tooth disease). Histological and electron microscopic studies (author's transl)]

Subacute cutaneous lupus erythematosus and interstitial myositis occurring with hepatitis B infection: response to antiviral therapy with lamivudine

Lupus erythematosus (LE) is a multisystem inflammatory disease resulting from an altered T- and B-cell response. Among various pathogenic factors, viral infections have been implicated in LE exacerbation. We describe a patient with acute onset of subacute cutaneous lupus erythematosus (SCLE) and interstitial myositis with mitochondrial changes in the context of an associated hepatitis B infection and the response of myositis to antiviral treatment with lamivudine. Viral vectors may play an important role in LE. A hitherto undescribed myositis with mitochondrial changes was associated with hepatitis B infection and SCLE and improved with antiviral treatment.

Two types of mitochondrial crystals in diseased human skeletal muscle fibers

Mitochondrial crystalline inclusions, frequently found in mitochondrial myopathies, were analyzed by crystallographic techniques and computer-aided image processing. It could be shown that these structures were real crystals. There are two distinct types of crystal, which can be distinguished by shape, size, and pattern. So-called type I crystals are usually present in the intracristal space, whereas the type II crystals are preferentially located in the intermembrane space between outer and inner mitochondrial membranes. The unit cell dimensions were found to be 38 x 34 x 8 nm for the type I crystals and 20 x 17 x 8 nm for the type II crystals. These results strongly suggest that the crystals are composed of macromolecules, presumably proteins. Arguments are presented that indicate that type I crystals occur only in type 1 muscle fibers and type II crystals in type 2 muscle fibers.

Myoclonus epilepsy associated with ragged-red fibres (mitochondrial abnormalities ): disease entity or a syndrome? Light-and electron-microscopic studies of two cases and review of literature

A report is given of an association of dyssynergia cerebellaris myoclonica associated with Friedreich's ataxia and mitochondrial myopathy in 2 patients. They had suffered from gradually increasing bursts of myoclonus since the wage of 14 and childhood, respectively. The other striking clinical features included generalized convulsions, mental deterioration, intention tremor, ataxia, muscular atrophy and deformity of feet. Muscle biopsies revealed ragged-red fibres in both cases. On electron microscopy these fibres contained subsarcolemnal aggregations of abundant abnormal mitochondria with proliferation of inner membranes or paracrystalline inclusions. One of these patients showed elevated blood lactate and pyruvate with an increased lactate/pyruvate ration, apparently of primary origin. These 2 cases resemble those reported briefly by Tsairis et al. (1974). An association of dyssynergia cerebellaris myoclonica associated with Friedreich's ataxia and mitochondrial myopathy in these 2 patients is unlikely to be coincidental but may represent one nosological entity. This myoclonus epilepsy syndrome associated with ragged-red fibres is compared with other possibly related mitochondrial encephalomyopathies.

The occurrence of paracrystalline mitochondrial inclusions in normal human skeletal muscle

Two different types of paracrystalline mitochondrial inclusions identical with or very similar to those already described in the literature for a variety of muscle diseases were found in human skeletal muscle biopsies obtained under general anesthesia before ischemia and after various periods of anoxia up to 150 min. As these crystalloids could be observed in seven of 14 healthy subjects and occurred in five of these seven cases either before or only 10 min after onset of ischemia, it is suggested that such mitochondrial inclusions develop not only under the influence of variant noxious stimuli, but may also represent a normal constituent of human skeletal muscle mitochondria.

Mixed nemaline-mitochondrial "myopathy"

A 4-year-old boy suffering from a nonprogressive muscular weakness had a muscle biopsy which ultrastructurally showed large aggregates of nemaline bodies and mitochondria in myofibers; occasional concentric lamellated bodies were present as well. The mitochondria were mostly at the periphery of collections of nemaline bodies, less commonly in their central portions. The light microscopic features differed from those of either nemaline or mitochondrial myopathy and were somewhat reminiscent of multicore disease. Evidence suggestive of possible neurogenic origin of both rods and mitochondria is reviewed.

Mitochondrial abnormalities of late motor neuron degeneration following poliomyelitis and other neurogenic muscular atrophies

A case of late motor neuron degeneration following poliomyelitis with abnormal mitochondria in muscle fibers is presented with two additional cases of systemic neurogenic muscular atrophy (Charcot-Marie-Tooth disease). Muscle biopsy revealed a neurogenic pattern of variable severity in all cases. Subsarcolemmal zones of hyperactivity and hyperpositive intermyofibrillar collections of granular material present in a variable proportion of type I fibers were demonstrated by oxidative enzymes. Ultrastructurally they corresponded to abnormal mitochondria, with paracrystalline inclusions in one case. The finding is discussed in the light of the previous literature on mitochondrial myopathies. Mitochondrial alterations are not specific and their significance in neurogenic conditions is debated.