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Biomedical subjects

X Dennett

Publications and source records attributed to X Dennett.

54 records · Page 3Linked to original sources
PubMed1988

Becker and Duchenne muscular dystrophy: a comparative morphological study.

It is important to be able to clearly differentiate between Duchenne (DMD) and Becker (BMD) muscular dystrophies in early childhood in order to offer more accurate prognostic information to parents. In response to this need, biopsies from BMD and DMD patients were compared to see which features, if any, allowed a differentiation to be made. Fifteen biopsies of vastus lateralis muscle from boys with the mild (BMD) X-linked muscular dystrophy were compared with 19 biopsies from patients with the severe (DMD) form using a variety of histochemical and morphometric parameters. Both forms showed many similarities including increases in fibre variation, percentages of Type 1 fibres, internal nuclei counts, split and fragmented fibres and groups of fibres attempting regeneration. Hypercontracted and necrotic fibres, interstitial inflammatory cells and endomysial connective tissue were more commonly increased in DMD. Fibre hypertrophy was initially prominent, particularly in DMD boys until 5 years of age and in BMD patients until approximately 10 years, thereafter the mean fibre sizes became smaller than normal. Type 2B deficiency was again common in DMD as well as occurring in some BMD cases. Nuclear aggregates and small group atrophy were more likely to be found in BMD. In the absence of morphological criteria to accurately discriminate between DMD and BMD, classification of young affected males with muscular dystrophy into one or other groups, remains a difficulty in the first decade of life.

Adolescent↗
PubMed1987

Chronic alcoholic proximal wasting: physiological, morphological and biochemical studies in skeletal muscle.

Electromyography, muscle histochemistry and assay of all glycolytic enzymes, phosphorylase, glycogen, carnitine and several mitochondrial marker enzymes in skeletal muscle (vastus lateralis) were carried out in two groups. One group comprised chronic alcoholic patients with prominent proximal wasting, the other was an alcoholic group with normal neuromuscular examination. Biochemical results were compared with data from control groups with normal muscle histology and with non-alcohol related type 2b fibre atrophy. Either 2b atrophy factor or 2b variability coefficient were increased in all wasted alcoholic patients, with normal values in alcoholics without wasting. Electromyography studies were usually normal in proximal muscles, although several patients had mild distal neuropathies. A significant fall in activity of phosphorylase and all glycolytic enzymes was found in wasted alcoholics with reference to normal controls. In the non-ethanolic 2b atrophy group the activity of several glycolytic enzymes was also significantly lower, but for each enzyme the mean activity was not depressed to the same extent as in the wasted alcoholic group. Muscle glycogen, carnitine, and mitochondrial marker enzyme activities (isocitrate dehydrogenase, monoamine oxidase, cytochrome oxidase) were normal in alcoholics with proximal wasting. It is concluded that there is no deficiency of mitochondrial marker enzymes in wasted alcoholics and that a significant depression in glycogenolytic and glycolytic enzyme activity is seen which is explained in part, but probably not fully, by 2b fibre atrophy.

Adult↗
PubMed1987

Mitochondrial studies in Kearns-Sayre syndrome: normal respiratory chain function with absence of a mitochondrial translation product.

Intact mitochondria were isolated from skeletal muscle of two patients with Kearns-Sayre syndrome (retinitis pigmentosa, heart block, chronic external ophthalmoplegia), and mitochondrial protein translation was measured. Mitochondrial protein synthesis was up to 10 times greater than in control subjects and SDS-polyacrylamide gel electrophoresis revealed absence of a translation product with the mobility of a 5 KDa protein. State 3 respiration rates were normal with site 1 and site 2 substrates, suggesting that the absent protein was not a functional subunit of a respiratory chain complex.

Adult↗
PubMed1987

Relapsing eosinophilic myositis--a cause of pseudothrombophlebitis in an alcoholic.

A 51-year-old chronic alcoholic man presented with recurrent calf and thigh swelling and was investigated on several occasions for possible deep venous thrombosis. The episodes were precipitated by binge drinking. Muscle biopsy was performed on 3 occasions, revealing an inflammatory myopathy. On one of these occasions eosinophils were prominent in the interstitial infiltrate. Eosinophilic infiltrates in skeletal muscle may be a transient phase of the cellular process in the inflammatory myopathy and perhaps do not denote a specific nosological entity.

Alcoholism↗
PubMed1986

Proximal motor neuropathy, dermato-endocrine syndrome, and IgG kappa paraproteinemia.

The association of monoclonal paraproteinemia, neuropathy, and dermato-endocrine disturbances is well recognized in Japan, and it also occurs in white patients. Neuropathy in such patients is classically distal and sensorimotor, and the paraprotein almost always contains lambda light chains. A 58-year-old white man presented with severe progressive proximal motor neuropathy, dermato-endocrine changes, and an IgG kappa paraprotein. Over a 2 1/2-year period, treatment with melphalan and prednisolone produced improvement in the neuropathy and resolution of dermato-endocrine features with a corresponding decline in the serum paraprotein concentration. Subsequent reappearance of the paraprotein, despite treatment, was associated with clinical relapse.

Endocrine System Diseases↗
PubMed1986

Dominantly inherited cardioskeletal myopathy with lysosomal glycogen storage and normal acid maltase levels.

A family is presented in which 7 members over 3 generations were affected by cardioskeletal myopathy. A vacuolar myopathy with excessive free and intralysosomal glycogen storage in skeletal and cardiac striated muscle was identified in biopsy studies. Post-mortem studies in several patients revealed changes of a congestive cardiomyopathy with myocardial fibrosis. Acid maltase, phosphorylase, debrancher and lysosomal enzyme screens, and glycolytic enzyme levels in skeletal muscle, were normal in 1 case. This is the third report of non-acid maltase deficient lysosomal glycogen storage disease and adds to previous reports with the presentation of detailed family studies, examined of ante- and post-mortem cardiac histology and reports of detailed glycolytic and lysosomal enzyme analysis. This syndrome is unusual among glycogenoses in having a dominant inheritance pattern.

Adult↗
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

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↗
PubMed1982

Function of the future respiratory system in the growth retarded fetal sheep.

The development of the future air breathing respiratory system was investigated in eight carunclectomised fetal sheep and five control fetal animals over the last third of gestation (approximately day 100-day 145). Carunclectomy resulted in the test fetal animals being hypoxaemic, hypercapnic, hypoglycaemic and acidotic. All fetal animals were chronically instrumented with diaphragmatic electromyographic leads, fetal jugular vein and carotid artery catheters, an amniotic fluid catheter and small electrocardiographic leads placed on the chest wall. There was evidence of a significant, but small, reduced relative lung size in the carunclectomised animals by day 140 without corresponding relative changes in the weight of the brain, liver, or heart. Diaphragmatic electromyograph (EMG) was analysed in detail over the last third of gestation. In both groups of animals, the normal reduction in fetal 'breathing' rate, and the normal increase in fetal apnoea was noted with increasing periods of diaphragmatic silence as fetal apnoea was noted with increasing periods of diaphragmatic silence as gestation advanced. Linear regression analyses revealed that fetal breathing rate was significantly reduced over the last third of gestation, whilst fetal apnoea significantly increased in the carunclectomised animals. Average total integrated diaphragmatic activity was reduced prior to 120 days. This reduction was evident in the strength of each diaphragmatic contraction before 110 days. In three test and three control animals, histochemical analyses were undertaken to fibre type the muscles of the diaphragm. Fatigue resistant fibres were significantly reduced in the carunclectomised fetuses, and fibre diameters were diminished. Centroid analyses of the power spectrum of the diaphragmatic EMG did not however support the concept of increased muscle fatigue in the test animals.

Animals↗
PubMedDate not supplied

Quadriceps muscle wasting persists 5 months after total hip arthroplasty for osteoarthritis of the hip: a pilot study.

AIMS: To determine whether additional muscle fibre wasting of the ipsilateral vastus lateralis muscle occurs in the early postoperative period after total hip arthroplasty for osteoarthritis of the hip and whether there is an improvement in preoperative measures of quadriceps muscle thickness, strength, pain and function over a 5-month postoperative period. METHODS: Twelve patients had ipsilateral needle quadriceps biopsy for muscle morphology and bilateral quadriceps muscle thickness ultrasound preoperatively, 5 days and 4 weeks postoperatively and a further muscle thickness measurement at 5 months. Seven additional patients and five age-matched control subjects had bilateral quadriceps muscle ultrasound thickness preoperatively, 6 weeks and 5 months postoperatively, with assessment of quadriceps muscle dynamometry, pain scores and Timed Up and Go (TUG) test. RESULTS: Preoperatively, all 19 patients demonstrated significant atrophy of the ipsilateral compared with the contralateral quadriceps muscle (P = 1.8 x 10(-7)) on muscle ultrasound, which persisted at 5 months follow up (P = 0.009). Muscle morphology preoperatively showed type 2A and 2B muscle fibre atrophy on needle muscle biopsy, with further atrophy of all three fibre types (P = 0.029) at 5 days postoperatively associated with a fibre type shift from type 1 to 2A fibres (P = 0.0011) at 1 month. There was improvement in hip pain postoperatively and a significant improvement in the TUG test (P = 0.007). However, there was no improvement in muscle strength on dynamometry. CONCLUSIONS: There is significant ipsilateral quadriceps atrophy and weakness with 2A and 2B fibre atrophy preoperatively in patients with osteoarthritis of the hip with exacerbation and further atrophy of all three fibre types 5 days postoperatively. Postoperative follow up showed that the reduction in ipsilateral quadriceps muscle thickness persisted at 5 months despite physical rehabilitation. Patients did note significant improvement in pain postoperatively and improvement on functional assessment with the TUG test. Other therapeutic strategies may have to be developed to reverse disuse muscle atrophy.

Aged↗
PubMedDate not supplied

Emetine myopathy in a patient with an eating disorder.

OBJECTIVE: To alert physicians to the dangers of a readily available, non-prescription drug by describing the clinical and pathological features of myopathy due to chronic poisoning with ipecac syrup in a patient with an eating disorder. CLINICAL FEATURES: A 27-year-old woman presented in 1991 with a right foot drop, followed a few months later by progressive severe neck and limb weakness associated with dysphagia, faecal incontinence and diffuse body ache. It emerged that she had been consuming increasing quantities of ipecac syrup (up to 200 mL per week) for three months to induce vomiting and weight loss. The serum creatine kinase activity was slightly elevated and electromyographic examination results were in keeping with a necrotising proximal myopathic process. Muscle biopsy showed vacuolar degeneration with myofibrilolysis and fine cytoplasmic body formation, consistent with a diagnosis of emetine myopathy. INTERVENTION AND OUTCOME: The patient was advised to stop taking ipecac and observed for the next few months. The symptoms resolved gradually and strength returned to normal in four months. CONCLUSION: Chronic emetine toxicity, with its potentially catastrophic consequences, should be remembered in the evaluation of neuromuscular symptoms in young women, in whom eating disorders are common and often unrecognised.

Adult↗