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J J Heffron

Publications and source records attributed to J J Heffron.

At least 73 records · Page 4Linked to original sources
PubMed1976

Weakness associated with the pathological presence of lipid in skeletal muscle: a detailed study of a patient with carnitine deficiencey.

A patient with muscular weakness demonstrating pathological lipid accumulation and abnormal mitochondria in skeletal muscle has been studied. The lipid accumulation and mitochondrial changes are thought to be related to the established deficiency of carnitine in this patient's muscle. The symptoms of muscular weakness associated with lipid accumulation in the skeletal muscle in the absence of complaint of muscle cramps or myglobinuria are thought to be diagnostic of carnitine deficiency. The failure of the sarcoplasmic reticulum to accumulate Ca2+ is discussed. The patient's strength responded dramatically when propranolol was added to his steroid therapy.

Adult↗
PubMed1976

Inhibition of actomyosin ATPase by high concentrations of 5-hydroxytryptamine. Possible basis of lesion in 5HT-induced experimental myopathy.

The effect of 5-hydroxytryptamine (5HT) on the ATPase activity and sulphydryl group reactivity of mammalian skeletal muscle actomyosin has been studied. 5HT inhibited the Mg2+-activated but not the Ca2+-activated ATPase activity of actomyosin. It slightly activated myosin ATPase. The sulphydryl groups of actomyosin reacting with 5,5'-dithiobis-(2-nitrobenzoic acid) were blocked by concentrations of 5HT which inhibited the Mg2+-activated ATPase. The significance of the results are discussed in relation to the muscle lesions in the experimental myopathy induced by 5HT and imipramine.

Actomyosin↗
PubMed1975

'Picture frame' fibres in a carrier of the trait for malignant hyperpyrexia.

A member of a family which was known to be susceptible to malignant hyperpyrexia, who was identified as a carrier by the presence of an elevated serum creatine-phosphokinase, has been investigated further. Muscle was examined biochemically, and the study included the sarcoplasmic ATPase-activity, actinomycin, Mg2+ ATPase activity, ATP, phosphocreatine and glucose-6-phosphate. In addition, the calcium uptake by the sarcoplasmic reticulum was studied. The histochemical analysis of the muscle revealed the presence of a new fibre type characterised by a dense rim of ATPase activity, which gives the impression of a 'picture-frame'. Ultramicroscopic study revealed changes in the mitochondria and areas of myofibrillar disruption with swelling of the sarcoplasmic reticulum.

Adenosine Triphosphatases↗
PubMed1975

Xanthine, hypoxanthine and muscle pain. Histochemical and biochemical observations.

A suspected case of xanthine oxidase deficiency has been further investigated. The patient complained of arthralgia and myalgia. Further studies included histochemical and ultramicroscopic analysis of muscle sarcoplasmic reticulum, and biochemical studies. High levels of xanthine and hypoxanthine were found, while uric acid was absent in the muscle extracts.

Adenosine Triphosphatases↗
PubMed1975

Predictive tests for malignant hyperpyrexia.

Four carriers of the abnormal trait for malignant hyperpyrexia have been studied to determine the value of the various methods of carrier detection. Tests included enzyme estimations, histochemistry, electronmicroscopy, biochemistry and in vitro exposure of muscle strips to halothane. By combining these procedures it is possible to detect all the asymptomatic carriers of this disease.

Adenosine Triphosphatases↗
PubMed1975

Morphological and biochemical defects in muscles of human carriers of the malignant hyperthermia syndrome.

This communication presents evidence in support of a neuropathic basis for the myopathy associated with malignant hyperpyrexia (MH). Muscle from MH susceptible individuals showed a reduced calcium uptake by the sarcoplasmic reticulum. There was a reduced concentration of phosphocreatine and ATP and an increased concentration of glucose-6-phosphate in these muscle samples.

Actomyosin↗
PubMed1975

Procaine in porcine malignant hyperthermia.

Serum creatine phosphokinase, rectal temperature and muscle pH at death were measured in three halothane-susceptible Landrace pigs. Two of the pigs were treated with procaine. Although the course of the syndrome was different in the treated pigs, procaine did not reverse the established malignant hyperthermia syndrome.

Animals↗
PubMed1975

Central core disease. A correlated genetic, histochemical, ultramicroscopic, and biochemical study.

Two patients suffering from central core disease are presented. The condition is associated with musculoskeletal abnormalities which have been traced back over five generations. In addition to the typical histochemical findings, electronmicroscopic study has revealed the presence of both structured and non-structured cores in adjacent areas. The calcium uptake by the sarcoplasmic reticulum was reduced to one-third of normal. Phosphorylase activity was normal in the one case and reduced to 63% in the other. Actomyosin Mg2+-activated ATPase activity was decreased, as was the Ca2+-dependent ATPase of the sarcoplasmic reticulum.

Adenosine Triphosphatases↗
PubMed1975

On the toxicity of procaine for pigs.

Procaine caused respiratory arrest in halothane-anaesthetized normal Landrace pigs at a dose of 4,2 - 8,2 mg/kg. In some cases death due to respiratory failure occurred after giving 10 - 13 mg/kg. Because of its toxicity in pigs procaine is unsuitable for treating the porcine malignant hyperthermia syndrome.

Anesthesia, Inhalation↗
PubMed1975

Factors affecting serum creatine phosphokinase activity in pigs.

Serum creatine phosphokinase activity was determined in German Landrace and Landrace x Large White pigs from 11 weeks to 28 weeks of age. A very pronounced age dependence of enzyme activity was observed in both groups, peak activities occurring at 19 weeks of age for the German Landrace and at 15 weeks for the crosses. The large increase in serum creatine phosphokinase activity observed occurred during the rapid phase of growth after which enzyme levels returned close to initial values. Sedatives and the stress of handling while obtaining blood can also cause raised serum creatine phosphokinase levels and complicate the interpretation of the data in regard to the detection of the stress syndrome. Enzyme activity also displayed a diurnal variation thus introducing a further parameter in the use of creatine phosphokinase activity for detection of the stress syndrome. Certain limitations in the method of measurement of creatine phosphokinase are discussed.

Age Factors↗
PubMed1974

The syndrome of 'continuous muscle-fibre activity' cured: further studies.

Two cases suffering from the syndrome of `continuous muscle-fibre activity' have been followed-up for 14 years. These patients have gradually gone into remission and no longer require therapy. The results of recent histology, histochemistry, and electronmicroscopy, as well as sural nerve biopsy studies, are presented. The sarcoplasmic reticulum calcium binding activity and ATPase activity are normal.

Actomyosin↗