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Biomedical subjects

D Pongratz

Publications and source records attributed to D Pongratz.

At least 127 records · Page 7Linked to original sources
PubMed1986

Fatal mitochondrial cardiomyopathy in Kearns-Sayre syndrome with deficiency of cytochrome-c-oxidase in cardiac and skeletal muscle. An enzymehistochemical--ultra-immunocytochemical--fine structural study in longterm frozen autopsy tissue.

Morphological studies in a 26-year-old man with long-standing Kearns-Sayre syndrome, with cardiac arrhythmias and a fatal congestive cardiomyopathy, revealed a mitochondrial myopathy of both skeletal and myocardial muscle (Hübner et al. 1986). Histochemical investigation of cytochrome-c-oxidase showed multiple enzyme defects of both cardiac and skeletal muscle present in myocytes with normal and abnormal numbers of mitochondria demonstrated by ultracytochemistry. Immunohistochemical studies with antibodies against the holoenzyme and various subunits revealed that in the heart the enzyme defect affected both contractile and conductive fibres and was characterized by a severe reduction but not a complete loss of nuclear and mitochondrially coded immunoreactive enzyme protein. In skeletal muscle, however, where up to 30% of the fibres lacked enzyme activity, immunoreactivity was reduced only very occasionally. These results are most consistent with a defective enzyme assembly in the inner mitochondrial membrane and probably indicate heterogeneity of mitochondria, i.e. organ-specific pathological reaction patterns.

Adult↗
PubMed1986

Activation of mitochondrial ATPase as evidence of loosely coupled oxidative phosphorylation in various skeletal muscle disorders. A histochemical fine-structural study.

Combined histochemical and biochemical studies have shown, that the histochemical activity of mitochondrial Mg2+-activated ATPase closely correlates with the coupling state of oxidative phosphorylation (Meijer and Vloedman 1980). Using this histochemical method 646 unselected skeletal muscle biopsies have been investigated. Activation of the enzyme, i.e. loosely coupled mitochondria were present either focally or diffusely expressed in 28% of the biopsies irrespective of the underlying disorder. Most often it was found in mitochondrial myopathies and in progressive muscular dystrophy type Duchenne; in a lesser degree it was also present in neurogenic atrophy and in various other disorders. Ninety two percent of all cases with loose coupling showed mitochondrial proliferations. On the other hand in 20% of all cases with mitochondrial proliferations including 19 cases of diffuse mitochondrial myopathy and 3 of progressive external ophthalmoplegia no activation of the enzyme was found. The results show that loose coupling is closely but not absolutely associated with mitochondrial proliferation, it is present in mitochondrial myopathies but also in various other muscular disorders with different pathogenesis.

Adenosine Triphosphatases↗
PubMed1986

[Cardiac manifestation of progressive muscular dystrophy of the Duchenne type].

Autopsy studies have shown that cardiomyopathy of Duchenne's muscular dystrophy (DMD) is characterized by fibrosis of the posterobasal and contiguous lateral wall of the left ventricle. This study was designed to determine whether stress testing would improve the sensitivity of echocardiography to detect secondary impairment of regional myocardial function. 12 patients aged 5 to 23 years with DMD were investigated. TM- and 2D-echocardiograms were performed before and during graded infusion of angiotensin (A) (0.5 to 5.0 mcg/min), and parameters of cardiac function analyzed. Satisfactory echocardiograms were obtained in all patients. Stress testing with A proved feasible in DMD and did not interfere with echocardiography. Before A all patients were in regular sinus rhythm and free of cardiac symptoms. Left ventricular function was normal in 9 patients and considered abnormal in 3 patients with hypokinesis and increased echo intensity of the posterobasal and lateral wall (2D short axis view) and/or a posterior wall to septal amplitude ratio of less than or equal to 1.1 (TM-echocardiogram). During A mean blood pressure rose and heart rate dropped significantly. 9 patients had marked supraventricular arrhythmias, 8 complained of dyspnea, cough or chest pain. Hypo- or akinesis of the posterobasal and sometimes the lateral wall was seen in 8, and a posterior wall to septal amplitude ratio of less than or equal to 1.1 in 9 patients. 3 patients, all with a muscle score of 60% or higher, remained free of symptoms and had no regional contraction abnormalities. Thus, clinical symptoms during A suggested latent congestive heart failure in many of the patients, and echocardiography identified provokable contraction abnormalities of such segments of the ventricular wall known to be most frequently involved in the dystrophic process in DMD. Stress testing revealed a correlation between clinical symptoms, abnormal echocardiographic findings and extent of the skeletal muscle disease in our study group. Physical limitation seems to protect the heart against demands that would otherwise cause earlier clinical manifestation of the cardiomyopathy in DMD.

Adolescent↗
PubMed1985

Mitochondrial myopathy with diffuse activation and focal deficiency of mitochondrial ATPase and carnitine deficiency.

In skeletal muscle from a patient with a mitochondrial myopathy and muscular carnitine deficiency, histochemical analysis demonstrated that mitochondrial ATPase showed activation with loss of latency even before addition of the uncoupler dinitrophenol (DNP). According to combined histochemical and biochemical studies by Meijer and Vloedman (1980), this finding indicates loosely coupled oxidative phosphorylation. After the addition of DNP the reaction intensity was markedly increased, but there were scattered enzyme-deficient fibres in which some residual activity was shown by ultracytochemistry. No defect in mitochondrial enzymes was found in biochemical studies. The enzyme histochemical changes and carnitine deficiency are probably both secondary to an unknown mitochondrial defect. Both the carnitine deficiency and the mitochondrial myopathy remained unchanged following long-term carnitine substitution therapy despite clinical improvement.

Adenosine Triphosphatases↗
PubMed1984

[Diagnostic significance of muscle biopsies in metabolic myopathies. II. Clinical biochemistry].

In the diagnosis of metabolic myopathies the use of biochemical methods, in addition to morphological examination of muscle biopsies, is often necessary in order to identify a specific metabolic defect. In order to narrow down the spectrum of biochemical methods, extensive clinical investigation and morphological examination, including histology, enzyme histochemistry and electromicroscopy if necessary have to be done beforehand. Patients are classified in the following groups: 1) progressive muscular weakness and/or muscle wasting with storage of a) glycogen, b) lipid or c) mitochondrial alterations; 2) recurrent rhabdomyolysis induced by fasting or exercise a) with glycogen storage or b) without any specific morphological alterations. The spectrum of metabolic defects comprises disorders of glycogen and glucose metabolism (deficiency of acid maltase, debranching and branching enzyme, phosphorylase, phosphofructokinase and other glycolytic enzymes), lipid metabolism (carnitine deficiency, carnitine palmitoyl transferase deficiency), mitochondria (respiratory chain disorders, pyruvate dehydrogenase deficiency) and others such as adenylate deaminase deficiency. In some of these e.g. infantile acid maltase deficiency and mitochondriopathies, it is clinically more important when organs other than muscle are affected; however, muscle biopsy is a useful substrate for diagnosis of these metabolic disorders.

Adult↗
PubMed1984

Myopathic carnitine deficiency associated with lymphocytic malignant non-Hodgkin lymphoma and monoclonal immunoglobulin G-K.

A 47-year-old male patient suffered from recurrent myalgia, induced by fasting or physical exercise. Later, he developed progressive muscular weakness. Serum levels of creatine phosphokinase (CPK) were elevated to approx. 400 U/1. Muscle biopsies showed lipid storage myopathy and signs of acute fiber necrosis, muscle carnitine was decreased to below 20% of controls, carnitine palmitoyl transferase (CPT) activity was normal. Carnitine was also moderately decreased in a liver biopsy and in plasma. Urine excretion of carnitine was low, no elevation of short-chain dicarboxylic acids could be found. The patient was also found to suffer from a lymphocytic malignant non-Hodgkin lymphoma, a monoclonal immunoglobulin (Ig) G-k in plasma and lymphocytic infiltration of bone marrow were demonstrated. At that time no evidence had been obtained to indicate that these two diseases could be related to each other. Autoantibodies against skeletal muscle could not be demonstrated. Absorption of L-carnitine p.o. was normal, however, plasma levels of carnitine fell again rapidly. Administration of 3 X 2 g L-carnitine per day normalized the patient's plasma carnitine levels and led to an increase of plasma short-chain acylcarnitine and ketone bodies, particularly beta-hydroxybutyrate (B-HOB). However, no significant clinical improvement could be seen. Additional application of prednisone led to normalization of CPK serum levels.

Carnitine↗
PubMed1984

[Diagnostic significance of muscle biopsies in metabolic myopathies. I. Myopathology].

The clinical course of metabolic myopathies is dominated by progressive muscle weakness and wasting or aching contraction and recurrent rhabdomyolysis with intense exercise. Vacuolar muscle fibre degeneration is the leading pathological finding on routine histological examination. For further characterization of those histologically empty looking vacuoles, histochemistry and electron microscopy are employed. Increase of glycogen, lipid droplets or mitochondria can often be demonstrated and indicate the need for subsequent biochemical identification of the underlying metabolic defect. Some other metabolic myopathies that cause recurrent rhabdomyolysis lack myopathological abnormalities. These can only be diagnosed biochemically, but additional new histochemical screening methods might be helpful.

Biopsy↗
PubMed1984

[Adult form of acid maltase deficiency presenting as progressive spinal muscular atrophy].

As far as could be elucidated, a sporadic manifestation of a slowly progressing muscular weakness and atrophy had commenced in a female patient symmetrically in the pelvic girdle and thigh region at the age of about 22 years. Only at the age of 55 years a precise neurological examination was done. On the basis of clinical and electromyographic data spinal muscular atrophy of the Kugelberg-Welander type was diagnosed. Muscular biopsy demonstrated severe far-progressed neurogenic muscular atrophy. In addition, increased storage of PAS-positive material was noticed. This was particularly true in the sparsely preserved, non-denervated muscular areas changed in the manner of an accompanying myopathy. Complementing electron microscopy and pathobiochemistry in the muscular biopsy showed an adult form of lack of acid maltase (Pompe's disease) aetiologically. This enzyme defect could also be demonstrated in the white cells of this patient.

Adult↗
PubMed1984

Mitochondrial myopathy with loosely coupled oxidative phosphorylation in a case of Zellweger syndrome. A cytochemical-ultrastructural study.

A newborn female, the second child of consanguineous parents, exhibited general muscle hypotonia, apathy, hepatomegaly and failure to thrive from birth and signs of craniofacial dysmorphia were present. Pipecolic and trihydroxicoprostanoic acid were excreted in the urine and serum transferrin, ferritin and iron were markedly elevated. At the age of 7 weeks the baby died of respiratory insufficiency. Besides malformations of the brain, renal cysts, liver damage with hypoplastic intrahepatic bile ducts and cholestasis, increased storage of iron and cytochemically proven deficiency of peroxisomes in liver and kidney, morphological studied provided evidence of a mitochondrial myopathy in striated muscle with the accumulation of enlarged bizarre mitochondria, showing only minor structural abnormalities. No defects of NADH-reductase, succinate-dehydrogenase or cytochrome-c-oxidase were demonstrated histochemically. Cytochemical-ultrastructural investigation of mitochondrial ATPase revealed activation of the ATP-synthesising enzyme even before the addition of an uncoupler, this indicating loosely coupled oxidative phosphorylation. In addition a high rate of subcellular autophagy with segregation of mitochondria and focal loss of fibrils was present. Muscle damage in Zellweger syndrome appears to be the consequence of complex, interacting metabolic processes. The mitochondrial myopathy thereby induced allows a better understanding of general muscle hypotonia, one of the leading symptoms of this disorder.

Adenosine Triphosphatases↗
PubMed1984

[Morphology of metabolic myopathies].

While muscular lesions in endocrine or metabolic diseases are fairly common primary metabolic myopathies are rare. In these, the metabolic fault is in the muscle fibre itself, which takes on a vacuolated appearance. In the majority of these myopathies there is an abnormality of the glycogen or fat metabolism due to the absence of a specific enzyme in most cases. By contrast, the pathogenesis of the so called mitochondrial myopathies is not yet well understood.

Carnitine↗
PubMed1983

Fatal lipid storage myopathy with deficiency of cytochrome-c-oxidase and carnitine. A contribution to the combined cytochemical-finestructural identification of cytochrome-c-oxidase in longterm frozen muscle.

Two newborn female siblings fell ill with apathy, failure of suckling and a generalized progressive muscular hypotonia. Death occured at the age of 7 weeks, obviously caused by impairment of respiratory musculature. Biochemical studies in one child revealed carnitine deficiency especially in skeletal muscle; hepatic encephalopathy was absent. Both children had a generalized hyperaminoaciduria, an unusual finding in primary carnitine deficiency. Besides fatty metamorphosis of the liver, bilateral hydroureters and tubular calcifications of both kidneys, morphological studies showed a generalized lipid storage myopathy which predominated in Type-I-fibres and was accentuated in the muscles of the neck. Enzymehistochemical electron microscopy in longterm frozen muscle demonstrated that cytochrome-c-oxidase activity was absent not only in myopathic but also in most of the morphological unchanged muscle fibres. Only some fibres and endothelial cells displayed normal activity of mitochondria. Biochemically no cytochrome aa3 (cytochrome-c-oxidase) could be found in skeletal muscle; cytochrome b was almost undetectable. --In newborns with fatal lipid storage myopathy and carnitine deficiency it seems necessary to look for additional defects in the respiratory chain. Enzyme histochemical electron microscopy is a sensitive method in identifying cytochrome-c-oxidase even after a 12 months period of storage.

Carnitine↗
PubMed1983

Focal deficiency of cytochrome-c-oxidase in skeletal muscle of patients with progressive external ophthalmoplegia. Cytochemical-fine-structural study.

In skeletal muscle biopsies of 8 patients with progressive external ophthalmoplegia combined light and fine structural cytochemical studies of cytochrome-c-oxidase revealed the absence of the enzyme in single fibres with or without accumulation of abnormal mitochondria. However, some fibres showed abnormal mitochondria without any deficiency of the enzyme. In one case with only slight mitochondrial proliferation the existence of the enzyme defect was the most remarkable finding. The occurrence of the enzyme defect obviously does not depend on concomitant structural alterations of the chondriom. The results are consistent with an acquired mitochondrial injury leading to a gradual loss of enzyme activity either earlier (with or without a minimal reactive mitochondrial proliferation) or later (after a phase of mitochondrial proliferation) in the course of the disease. Focal lack of cytochrome-c-oxidase activity is apparently a constant feature of the syndrome; it therefore may be not only of pathogenetic but also of diagnostic importance and in this connection cytochemical-fine-structural demonstration of cytochrome-c-oxidase is a valuable method. In contrast to the biochemical approach it allows not only the detection but also the exact anatomical localization of single fibre defects.

Biopsy↗
PubMed1981

Pseudohypoparathyroidism and hypocalcemic "myopathy". A case report.

A patient with the clinical features of pseudohypoparathyroidism and elevated concentrations of serum CK and LDH, which normalized after successful therapy, is described. Clinical signs of myopathy did not exist. The bioptical material from the m. tibialis anterior was microscopically normal. The biochemical analysis revealed a reduced phosphorylase-a-activity with the total phosphorylase-activity (a and b) being within the normal range. The significance of these findings as well as possible pathogenetic mechanisms are discussed.

Adolescent↗