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Biomedical subjects

S DiMauro

Publications and source records attributed to S DiMauro.

At least 307 records · Page 17Linked to original sources
PubMed1987

Mitochondrial encephalomyopathy and partial cytochrome c oxidase deficiency.

A 52-year-old man had slowly progressive weakness and wasting of limb-muscles, sensorineural hearing loss, and complex partial seizures. CT showed cerebral atrophy, but he was not demented. Muscle biopsy showed ragged-red fibers and decreased histochemical stain for cytochrome c oxidase. Biochemical studies showed decreased cytochrome c oxidase activity in crude muscle extracts and in isolated mitochondria (44 and 30% of normal), while other mitochondrial enzymes were normal. A comparable decrease of immunologically reactive enzyme protein was shown by immunotitration with antibodies against human heart cytochrome c oxidase. Partial defects of cytochrome c oxidase may cause adult-onset, slowly progressive mitochondrial encephalomyopathies.

Atrophy↗
PubMed1987

Benign reversible muscle cytochrome c oxidase deficiency: a second case.

A 6-week-old boy had generalized weakness, requiring assisted ventilation, and lactic acidosis. At 6 months, the lactic acidosis resolved, and the patient started to improve; assisted ventilation was discontinued at 15 months. Muscle biopsies at 4 and 11 months showed accumulation of mitochondria, lipid, and glycogen; cytochrome c oxidase (COX) activity was 11% of the lowest control in the first biopsy and 57% in the second. Immunocytochemistry and immunotitration showed presence of immunologically reactive enzyme protein in both biopsies. This case confirms a previous report of benign infantile myopathy due to reversible COX deficiency. The severe fibrosis in the second biopsy may explain the slower rate of clinical recovery in this child.

Biopsy↗
PubMed1987

Cardiomyopathy, mental retardation, and autophagic vacuolar myopathy.

Two brothers had nonobstructive hypertrophic cardiomyopathy, mental retardation, and vacuolar myopathy, and their mother died of cardiopathy at age 31. Seven families with this syndrome have been described; heredity appears to be X-linked dominant or autosomal dominant, with different expressivity in males and females. The biochemical cause of this lysosomal storage disease is unknown.

Adolescent↗
PubMed1987

McArdle's disease in two generations: autosomal recessive transmission with manifesting heterozygote.

A 17-year-old boy had exercise-induced cramps and myoglobinuria. The mother had myalgia and weakness after exercise but the father was asymptomatic. Muscle biopsy was normal in the father but showed glycogen storage and absent or markedly decreased histochemical stain for phosphorylase in mother and son. Autosomal dominant McArdle's disease was considered likely, but biochemical studies showed that muscle phosphorylase activity was 0.6% of normal in the son, 20% in the mother, and 45% in the father, with corresponding decreases of cross-reacting material by immunotitration. These data suggest autosomal recessive transmission. One of the parents was clinically silent and the other was a manifesting heterozygote.

Adolescent↗
PubMed1986

Myoadenylate deaminase deficiency.

This report concerns two unrelated males; one had sarcoidosis, sarcoid myopathy and muscle weakness, and the other had exercise-induced weakness and myalgia. Both patients had a lack of ammonia rise in their serum after an ischemic work test, minimal histochemical activity of myoadenylate deaminase in repeated muscle biopsies, and less than 5% of normal biochemical activity of myoadenylate deaminase in their skeletal muscles. These three criteria establish primary myoadenylate deaminase deficiency as a separate primary metabolic muscle disease which merits differential diagnostic consideration when patients complain of muscle weakness and cramps.

AMP Deaminase↗
PubMed1986

Myopathy and fatal cardiopathy due to cytochrome c oxidase deficiency.

A 3-day-old girl had a syndrome of lethargy and lactic acidosis. Pregnancy and delivery had been normal; there was no consanguinity or family history of neuromuscular disease. At age 4 1/2 months, she had generalized weakness, hypotonia, areflexia, and macroglossia. She developed cyanosis and respiratory failure, and marked cardiomegaly was noted. She died at age 8 1/2 months of cardiac arrest. Results from a muscle biopsy specimen obtained at age 4 1/2 months showed ragged-red fibers and increased glycogen and lipid droplets. With the cytochrome c oxidase reaction, only 5% of the fibers stained positively in the biopsy specimen. Cytochrome c oxidase activity was 7.3% of normal in muscle mitochondria and 12.2% of normal in heart mitochondria. Reduced-minus-oxidized cytochrome spectra showed lack of the cytochrome aa3 peak. Immunotitration using antibodies against purified human heart cytochrome c oxidase showed normal amount of cross-reacting material in both heart and muscle. The genetic error could have involved a cytochrome c oxidase isozyme common to heart and muscle.

Cytochrome-c Oxidase Deficiency↗
PubMed1986

Metabolic myopathies.

Six glycogen storage diseases (resulting from deficiencies of acid maltase, phosphorylase, phosphofructokinase, phosphoglycerate kinase, phosphoglycerate mutase, and lactate dehydrogenase) and one mitochondrial myopathy (cytochrome c oxidase deficiency) are reviewed to illustrate: clinical heterogeneity, biochemical heterogeneity, evidence for tissue-specific and developmentally controlled isozymes, and molecular genetic studies.

Bisphosphoglycerate Mutase↗
PubMed1986

Fatal infantile form of muscle phosphofructokinase deficiency.

We studied a girl with an infantile syndrome of limb weakness, seizures, cortical blindness, and corneal opacifications; she died at age 7 months of respiratory failure. There was no consanguinity or family history of neuromuscular diseases. Histochemical and biochemical studies of muscle showed mildly increased glycogen content and markedly decreased PFK activity (1.4% of the normal mean). Anaerobic glycolysis in vitro confirmed the metabolic block. Immunofluorescence and immunotitration by ELISA using monoclonal antibodies against subunit M of PFK showed a normal amount of cross-reacting material. The brain showed typical features of neuroaxonal dystrophy. This variant of PFK deficiency may be due to a distinct genetic defect.

Brain Diseases↗
PubMed1986

Juvenile-onset acid maltase deficiency with unusual familial features.

From early childhood, two brothers had mild gait difficulties due to acid maltase deficiency (AMD). Biochemical studies of family members were consistent with autosomal recessive inheritance, but the asymptomatic mother had AM activity in the homozygote range, and her parents had decreased AM activity. The asymptomatic mother may be homozygous for the adult-onset variant of AMD. Alternatively, either the mother or the children may be genetic compounds of the childhood and adult forms of AMD.

Adult↗
PubMed1985

Immunocytochemical analysis of normal and acid maltase-deficient muscle cultures.

Muscle cultures from patients with infantile and later-onset acid maltase deficiency (AMD) and from unaffected controls were studied immunocytochemically with anti-acid maltase (anti-AM) antibodies and fluorescein-labeled goat anti-rabbit IgG second antibody. In control muscle cells, an intense granular distribution of staining was seen, consistent with lysosomal localization of AM. Cultured muscle cells from two patients with infantile AMD (Pompe's disease) did not fluoresce, whereas cells from two patients with AMD of later onset did fluoresce, showing a distribution similar to that of controls.

Acid Phosphatase↗
PubMed1985

X-linked glycogen storage disease. A cause of hypotonia, hyperuricemia, and growth retardation.

Seven male members of one family had a form of glycogen storage disease that was inherited in an X-linked recessive pattern. The clinical manifestations included hepatomegaly, delay in growth and sexual maturation, muscular weakness in childhood, and gouty arthritis. The cause of the glycogen accumulation did not appear to be a deficiency of glucose 6-phosphatase, debrancher enzyme, phosphorylase, or phosphorylase kinase. Prognosis appeared to be good although there was significant disability during childhood.

Adolescent↗
PubMed1985

Fatal infantile mitochondrial myopathy and renal dysfunction caused by cytochrome c oxidase deficiency: immunological studies in a new patient.

A 3-month-old female infant had profound generalized weakness, de Toni-Fanconi-Debre syndrome, and lactic acidosis. She required assisted ventilation and died at the age of 8 months. Muscle biopsy showed accumulation of mitochondria, glycogen, and lipid droplets. Histochemical reaction and immunocytochemical stain for cytochrome c oxidase showed very weak results, but both reactions were normal in intrafusal fibers of the muscle spindle. In crude extracts of the patient's muscle, cytochrome c oxidase activity was undetectable and enzyme-linked immunosorbent assay showed decreased reaction at all dilutions of antiserum. These data indicate that the amount of immunoreactive enzyme protein is markedly decreased in muscle of patients with fatal infantile cytochrome c oxidase deficiency and renal dysfunction.

Biopsy↗
PubMed1985

Mitochondrial myopathies.

Mitochondrial myopathies are clinically heterogeneous disorders that can affect multiple systems besides skeletal muscle (mitochondrial encephalomyopathies or cytopathies) and are usually defined by morphological abnormalities of muscle mitochondria. There are a few distinctive syndromes, such as the Kearns-Sayre syndrome; myoclonus epilepsy with ragged-red fibers; and mitochondrial myopathy, encephalopathy, lactic acidosis, and strokelike episodes. Biochemically, mitochondrial myopathies can be divided into defects of substrate utilization, oxidation-phosphorylation coupling, and the respiratory chain. Because mitochondria have their own DNA and their own translation and transcription apparatuses, mitochondrial myopathies can be due to defects of either a nuclear or mitochondrial genome and can be transmitted by mendelian or maternal inheritance.

Carnitine↗
PubMed1985

Beta-oxidation enzymes in normal human muscle and in muscle from a patient with an unusual form of myopathic carnitine deficiency.

In a reported patient with myopathic carnitine deficiency, addition of exogenous carnitine to muscle homogenates failed to correct palmitate oxidation, and oral carnitine was of no clinical benefit. In a muscle biopsy from this patient, we found that, in contrast to the marked deficiency of free carnitine (3% of normal) short- and medium-chain acylcarnitines were in the normal range and long-chain acylcarnitine was increased almost four times. As this result confirmed the hypothesis of a muscle defect of mitochondrial oxidation of palmitate, all eight enzymes of beta-oxidation were measured spectrophotometrically in the muscle extract. None of them was found to be defective. These data suggest that the underlying biochemical abnormality in this patient may be a deficiency of the carnitine-acylcarnitine translocase system or a defective interaction between acyl-CoA dehydrogenase and its flavoprotein coenzyme.

Acyltransferases↗