G Hübner's research while affiliated with Ludwig-Maximilians-University of Munich and other places

The pathophysiological significance of the mitochondrial microangiopathy in MELAS (mitochondrial encephalopathy, lactic acidosis, and strokelike episodes) syndrome was evaluated in an autopsy study of a nearly 13-year-old girl who had suffered from multiple infarctlike lesions in the brain, a mitochondrial myopathy-cardiomyopathy, and a generalized mitochondrial microangiopathy. Cytochemically, defects of cytochrome c oxidase (complex IV) were visualized by light and electron microscopy in the skeletal and heart muscle and in the altered vessels, as well as in single bile duct cells, with the activity of the hepatocytes being diffusely reduced, whereas in the brain, the cytochemical activity was only slightly diminished. Biochemical studies revealed a 50% reduction of both NADH (the reduced from of nicotinamide-adenine dinucleotide) dehydrogenase (complex I) and complex IV in the skeletal muscle. In the brain, complex I was diminished to 20%, whereas complex IV was only slightly below the low-normal range. Immunohistochemical studies with the use of subunit-specific antiserum samples against cytochrome c oxidase showed a varying protein profile, with loss of both mitochondrially and nuclearly derived subunits being most pronounced in the heart muscle and lesser in the skeletal muscle. In the brain, liver, bile ducts, and especially the vessels, no loss of enzyme protein content was observed. The results illustrate heterogeneous tissue expression of respiratory chain defects in MELAS syndrome and indicate that vascular cytochrome c oxidase deficiency may be involved in the cerebral manifestation of the disease, whereas in other organs like the heart, a similar pathogenetic importance of the microangiopathy cannot be verified.

A family with mitochondrial myopathy, encephalopathy, lactic acidosis and strokelike epidoses (MELAS) affecting mother, son and daughter is described. Biochemical studies on muscle biopsy specimen in one patient revealed NADH dehydrogenase (complex I) deficiency. A mitochondrial angiopathy could be demonstrated by brain and muscle biopsy. It is suggested that the mitochondrial angiopathy is the basic pathogenic mechanism of impaired cerebral circulation in MELAS.

Malignant hyperthermia (MH) is a pharmacogenetic myopathy triggered by a variety of anaesthetic agents and muscle relaxants. In humans, susceptibility to MH is inherited as an autosomal dominant trait, and susceptible patients do not show a clinically relevant myopathy unless having suffered from a MH crisis. Homozygosity for the MHS trait is thought to be an uncommon finding, and so far only a few cases of patients suggested to be homozygous for MH on the basis of pedigree information were reported and described as having a more severe form of this condition resulting in clinical symptoms also in the absence of triggering agents. We report clinical findings in a patient with chronic myopathy beginning at the age of 2 yr and associated with a number of unique features, the most important being a family history of MHS present in both parents. She became symptomatic with marked muscular weakness and elevated serum CK levels. A muscle biopsy showed a distinct enlargement and increase of muscle mitochondria. In the in vitro contracture test the patient's muscle responded with unusually high contractures already at basal levels of triggering agents indicating a particularly severe MHS condition. DNA markers for the MHS1 locus, described previously on chromosome 19q12-13.2 in Irish and Canadian pedigrees, could not be used to confirm her homozygous state because our molecular genetic studies had previously excluded the MHS trait in this pedigree from this locus.(ABSTRACT TRUNCATED AT 250 WORDS)

A 5-month-old boy died of progressive heart failure that started at the age of 3 months. Autopsy revealed a mitochondrial cardiomyopathy and a mitochondrial myopathy of the limb muscle and diaphragm. Cytochemically random defects of cytochrome c oxidase were visualized by light and electron microscopy in the diaphragm and especially the heart muscle, the limb muscle showing a diffuse attenuation whereas the liver and kidneys reacted normally. The activities of NADH-dehydrogenase (complex I) and cytochrome c oxidase (complex IV) were severely diminished (20% residual activity of controls) in the skeletal and heart muscle. In the heart, succinate cytochrome c reductase (complex II/III) was additionally decreased to the same degree. Loss of cytochrome c oxidase activity was based on a reduction of both mitochondrial and nuclear derived subunits in the heart and diaphragm as revealed by immunohistochemical analysis, whereas the limb muscle showed a normal immunoreactive protein content. The results illustrate heterogeneous tissue expression of respiratory chain enzyme defects and demonstrate that a cardiomyopathy may be the leading presentation of a mitochondrial disorder in early infancy.

We report about two female patients with a histopathological proven granulomatous myositis associated with a fasciitis. One patient showed noncaseating granulomas in the muscle fascia. She suffered from symmetrical contractures of the digital flexors and ankles. The second patient showed uveitis and polyneuropathy, too. In addition, increased activities of the angiotensin-converting-enzyme and lysozyme in the sera suggested that both cases represent a new form of sarcoidosis.

We report about two female patients with a histopathological proven granulomatous myositis associated with a fasciitis. One patient showed noncaseating granulomas in the muscle fascia. She suffered from symmetrical contractures of the digital flexors and ankles. The second patient showed uveitis and polyneuropathy, too. In addition, increased activities of the angiotensinconverting-enzyme and lysozyme in the sera suggested that both cases represent a new form of sarcoidosis.

Lack of cytochrome-c oxidase activity and of cytochromes aa3 + b has been reported previously in the skeletal muscle of one of two siblings (Müller-Höcker et al, 1983). The present study reports a deficiency of immunoreactive enzyme protein in the skeletal muscle of both siblings, who had an identical fatal clinical course. In all specimens the defect did not involve the whole enzyme protein, but was selectively expressed in the mitochondrially derived subunits II/III and nuclear coded subunits VIIbc. Neither the specific fibers of the muscle spindles nor the mitochondria of the heart, liver, kidneys, vessel walls and/or gastrointestinal tract were affected. These results are most consistent with a primary nuclear defect being responsible for the organ specific and subunit selective expression of the enzyme defect.

Myositis was proven histopathologically in 4 patients (age range 36-66 years) who suffered from early or late stages of Borrelia burgdorferi infection. Muscle weakness was present in 3 patients, 1 complaining of additional myalgias. One man came to medical attention because of skin discoloration and swelling of one leg. Deep biopsy from skin, fascia and muscle revealed acrodermatitis chronica atrophicans, panniculitis, fasciitis, and myositis, respectively. Creatine kinase was slightly elevated in 3 cases and normal in one. Infiltrates were found in the perimysium and within the muscle bundles, mainly around small vessels. The infiltrates consisted of many B cells and T4 lymphocytes with fewer cytotoxic T cells, suggesting that Borrelia myositis might be due to a local immune response to unknown Borrelia antigens. Cultivation of Borrelia from muscle was not successful. Antibiotic therapy cured the myositis.

A severe copper storage disease of the liver with micronodular cirrhosis resembling Indian childhood cirrhosis (ICC) was found in two siblings of a German family leading to death in one infant at the age of 13 months. The fatal outcome correlated with severe ballooning of hepatocytes and excessive formation of Mallory bodies. The copper content of the liver was 698 micrograms per gramme wet weight (control 5 micrograms) in the living patient and 2154 micrograms per gramme dry weight (controls 39, 54 micrograms) in the dead infant. In both cases copper was stored not only in hepatocytes but also to a high degree in mesenchymal cells. Chronic contamination of drinking water supplied from a well via copper pipes could be verified as the cause of copper intoxication, lending further support to ICC as an environmental, acquired disorder. Accumulation of exogenic copper already very early in infancy appears most important for the development of the disease, as both the parents and one child not exposed to copper intoxication during the first 9 months of its life are clinically healthy.