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Biomedical subjects

E Byrne

Publications and source records attributed to E Byrne.

At least 145 records · Page 8Linked to original sources
PubMed1985

Partial cytochrome oxidase (aa3) deficiency in chronic progressive external ophthalmoplegia. Histochemical and biochemical studies.

Biochemical and histochemical studies were carried out on 2 patients with chronic progressive external ophthalmoplegia (CPEO). Histological examination revealed prominent ragged-red fibres in the Gomori trichrome stain and cytochrome oxidase staining revealed partial depletion of cytochrome oxidase with negative staining in some fibres with prominent subsarcolemmal mitochondrial aggregations. Polarographic studies with isolated intact skeletal muscle mitochondria revealed low State III respiration rates with NAD- and FAD-linked substrates. Cytochrome aa3 levels were depressed in the one case where a cytochrome difference spectra was recorded. Cytochrome oxidase levels were greatly depressed in muscle homogenate, whereas monoamine oxidase levels were in the normal range, indicating a selective depletion of the former enzyme complex. It is possible that deficiency of cytochrome oxidase may arise as an epiphenomenon in degenerating mitochondria rather than a primary deficiency.

Adolescent↗
PubMed1985

Mitochondrial myoneuropathy with respiratory failure and myoclonic epilepsy. A case report with biochemical studies.

A 55-year-old man is presented who developed severe multifocal myoclonus and tonic clonic seizures in his early thirties, and progressive limb weakness in his mid forties, when a ragged red fibre myopathy was diagnosed. He went on to develop a distal motor neuropathy and respiratory failure. Respiratory function tests indicated respiratory failure secondary to respiratory muscle weakness and a central hypoventilation syndrome. CT scan revealed brain stem atrophy and brain stem evoked responses were abnormal. A sural nerve biopsy showed severe axonal degeneration. Cytochrome difference spectra and polarographic studies on isolated intact muscle mitochondria were normal. This study reports the association of respiratory failure and sleep apnoea with Fukuhara's syndrome and presents biochemical data suggesting that the mitochondrial respiratory chain may be intact in some patients with this syndrome.

Adenosine Diphosphate↗
PubMed1985

Oxygen electrode studies with human skeletal muscle mitochondria in vitro. A re-appraisal.

Polarographic measurement of respiration rates in skeletal muscle mitochondria is a valuable research tool in human disease but the data on normal muscle are sparse and conflicting. In this study, mitochondria were isolated from 18 normal muscle biopsies and state 3 respiration rates measured with glutamate/malate, pyruvate/malate and succinate as substrates. In 13 experiments, reproducible respiration rates with adequate respiratory control ratios (RCR) and ADP/O ratios were obtained. Mean state 3 respiration rates of 280 ng-atoms 0 min-1 mg mitochondrial protein-1 (30 degrees C) with glutamate, 214 ng-atoms 0 min-1 mg mitochondrial protein-1 (30 degrees C) with pyruvate and 353 ng-atoms 0 min-1 mg mitochondrial protein-1 (30 degrees C) with succinate as substrates were higher than in most earlier reports. Selective uncoupling with alpha-glycerophosphate and data suggesting a partial site I deficiency were found in some experiments where RCR and ADP/O ratio measurements indicated a good preparation. Slow rates with all substrates with loose coupling were found in 3 studies where the mitochondria were clearly damaged during extraction. Guidelines for the evaluation of polarographic data in reports in the literature are suggested.

Adenosine Diphosphate↗
PubMed1985

Intradural cyst with compression of the cauda equina in ankylosing spondylitis.

A cauda equina syndrome complicating long-standing ankylosing spondylitis was found to be due to a large multiloculated cyst. This differed from posterior dural diverticula identified in similar cases in that the cyst filled the lumbar canal with erosion of the upper lumbar vertebral bodies and chronic inflammatory changes were evident in the cyst wall. Cauda equina compromise in ankylosing spondylitis has several possible mechanisms including fibrosis following arachnoiditis, root damage by dural diverticula, and direct compression by arachnoid cyst.

Aged↗
PubMed1985

Chronic relapsing myalgia (? Post viral): clinical, histological, and biochemical studies.

Two patients with persistent myalgia characterised by onset after an ill-defined systemic illness, marked fluctuations in the severity of the symptoms, and normal neuromuscular examination with the exception of variable muscle tenderness on deep palpation, may have a forme fruste of myalgic encephalomyelitis. Differentiation from psychogenic muscle pain is important in management. Muscle histology revealed non-specific Type II fibre atrophy. Mitochondrial respiration was assayed polarographically in intact organelles in vitro and revealed a mild depression of State 3 respiration rates with Site I and Site II substrates.

Adult↗
PubMed1984

Physical and psychological health of children of Type 1 (insulin-dependent) diabetic mothers.

No difference was found at paediatric assessment, or by a psychologically-based maternal and teacher questionnaire of the emotional state or academic achievement, between 123 children of Type 1 (insulin-dependent) diabetic mothers and 124 children of non-diabetic mothers. The groups were closely matched for maternal age, sex and position in sibship of the child, and age and home environment of the mother. The children of diabetic mothers had all been delivered before week 38 of gestation.

Achievement↗
PubMed1984

Mitochondrial myopathies: disorders of the respiratory chain and oxidative phosphorylation.

Mitochondrial myopathies are a clinical condition characterized by muscle weakness and fatigue in which the primary defect is localized at the level of the mitochondria. Microscopic examination shows accumulations of mitochondria at the fibre periphery (ragged red fibres) and in some cases mitochondrial paracrystalline inclusions. The spectrum of different mitochondrial defects so far described is reviewed and data from cases investigated in this laboratory are described. The first case was a 17-year-old boy with a multisystem disorder whose muscle mitochondria showed low respiratory activity with all substrates, which doubled in the presence of uncoupler. Further investigation showed that the mitochondrial ATPase activity was only 6% of normal. The next cases were a mother and daughter who showed a typical lipid storage myopathy. The latter was treated successfully with oral carnitine but the myopathy persisted. Mitochondrial investigations indicated a low respiratory activity with NAD-linked substrates but normal activity with succinate and ascorbate + TMPD. A defect in the NADH-CoQ reductase section of the respiratory chain was pinpointed possibly at an iron-sulphur centre. The fourth and fifth cases were two sisters who exhibited no lipid storage myopathy but whose mitochondrial activity was low with NAD-linked substrates but normal with succinate. Again a defect in the NADH-CoQ reductase (complex I) of the respiratory chain was determined. They were also investigated using 31P-NMR. It was found after exercise that their muscle creatine phosphate levels took seven times longer to return to pre-exercise concentrations than control subjects. These results are discussed with respect to the synthesis of mitochondrial proteins and the influence that both the mitochondrial and nuclear DNA have on this process.

Adolescent↗
PubMed1984

Polymyositis presenting with respiratory failure.

A 36-year-old woman presented with a 3-month history of increasing dyspnoea, culminating in respiratory failure due to paralysis of respiratory muscles. She required assisted ventilation. Subsequently, mild limb and neck weakness was noted. Muscle biopsy of the right vastus lateralis showed polymyositis. The patient died suddenly and the postmortem revealed polymyositis with predominant involvement of the diaphragm and intercostal muscles.

Adult↗
PubMed1984

Hypopituitarism associated with myalgia.

A patient with panhypopituitarism who presented with muscle pain and stiffness is described. These symptoms responded rapidly to treatment with thyroxine and cortisone acetate. The association between muscle disease and hypopituitarism is briefly reviewed.

Humans↗
PubMed1983

Clinical features of mitochondrial myopathy.

Five patients with mitochondrial myopathy are discussed. Two presented with progressive external ophthalmoplegia (CPEO), one with CPEO and retinitis pigmentosa, and two with Kearns-Sayre syndrome. Ragged red fibres and intra-mitochondrial paracrystalline inclusions were found in each case. The clinical heterogeneity of the mitochondrial myopathy syndrome in the presence of identical pathological changes in skeletal muscle is emphasised.

Adult↗
PubMed1982

Central core disease. Study of a family with five affected generations.

A family is described in which at least 37 members in five generations living in Australia have suffered from a rare congenital myopathy--central core disease (CCD). Histochemical and ultrastructural features typical of CCD were present on muscle biopsy. Although there are variations in clinical expression, a relatively benign and nonprogressive course is usual. Inheritance of CCD in this family conforms to an autosomal dominant pattern with a high degree of penetrance.

Adult↗
PubMed1982

Familial extrapyramidal disease with peripheral neuropathy.

A family is presented in which 10 members over three generations developed a Parkinsonian syndrome. Two siblings had additional clinical and electrophysiological evidence of an associated peripheral neuropathy and sural nerve biopsy in one case revealed axonal loss. This is the third family reported in the literature in which an extrapyramidal syndrome is associated with neuropathy, but differs from earlier reports in that neuropathic involvement was due to axonal degeneration rather than segmental demyelination.

Adult↗