glycogen and Thyroid-Diseases

Nuclear magnetic resonance (NMR) spectroscopy is a new technique to study myocardial metabolism in living tissues by noninvasive means. The biochemical studies on intact hearts are performed in multinuclear NMR spectrometers using Fourier transform techniques for data acquisition. The biological NMR experiments preserve the tissues and can be repeated with a temporal resolution of seconds to several minutes in a reproducible fashion. As a marker of the intermediary metabolism P-31, C-13, H-1, F-19, N-14, Na-23, and K-39 isotopes are commonly used. NMR spectrum analysis permits the identification of several important substrates of the myocardial metabolism and their concentrational changes. In addition, the biophysical parameters of magnetic relaxation properties are measured. In some instances enzyme kinetics can be assessed. The disadvantage of NMR spectroscopy is the low sensitivity: only substrates with a intracellular concentration of greater than or equal to 0.5 mM can be detected. Improvements in sensitivity can be achieved, if the number of scans per spectrum and magnetic field strength are increased. The application of NMR spectroscopy in cardiovascular medicine is new and systematic studies on myocardial metabolism in vivo are not yet available. However, using P-31 MR spectroscopy several important results concerning the changes of the high energy phosphates and the intracellular pH changes during myocardial ischemia, as well as interesting insights into the regulatory principles of the cellular respiration were obtained. Similarly, C-13 NMR spectroscopy successfully described some aspects of glycogen metabolism and the kinetics of citric acid cycle in the myocardium. The clinical application of NMR spectroscopy appears feasible in a near future. The practical importance of this promising technique in clinical cardiology will depend on availability of the whole-body MR spectrometers, on the development of pertinent techniques for spatial MR signal resolution, and on our ability to uncover and to understand the biochemical principles of cardiac diseases. However, it is already today evident that MR spectroscopy successfully shifted the research interests towards biochemical processes at the cellular level as important causes and markers of cardiac diseases and extended our knowledge of the pathophysiology of the myocardium.

Topics: Animals; Coronary Disease; Creatine Kinase; Dogs; Glycogen; Guinea Pigs; Heart; Humans; Magnetic Resonance Spectroscopy; Models, Biological; Myocardium; Phosphates; Rabbits; Rats; Thyroid Diseases

Geriatric cardiology requires special knowledge and experience. It is not possible to extrapolate directly experience obtained with young patients to old people. Because of the multiple illnesses, many serious, in the elderly cardiac patients, it is imperative for the cardiologist to be, first of all, a master internist at all times. Old patients with their multiple illnesses are also sensitive to drugs, including digitalis and diuretics. There is a need to train more physicians in geriatric cardiology in order to offer the old patient the best of care since so many old people are living today. There is also a need to learn the effects of the aging process itself on the human heart. Such studies should command priorities in financial and other forms of support.

Topics: Age Factors; Aging; Aortic Valve Insufficiency; Aortic Valve Stenosis; Cardiac Output; Dyspnea; Edema; Electrocardiography; Female; Glycogen; Heart; Heart Diseases; Heart Function Tests; Histocytochemistry; Humans; Hypertension; Hypotension, Orthostatic; Male; Microscopy, Electron; Myocardium; Radiography; Rheumatic Heart Disease; Thyroid Diseases; Vectorcardiography

McArdle disease is caused by recessive mutations in PYGM gene. The condition is considered to cause a "pure" muscle phenotype with symptoms including exercise intolerance, inability to perform isometric activities, contracture, and acute rhabdomyolysis leading to acute renal failure. This is a retrospective observational study aiming to describe phenotypic and genotypic features of a large cohort of patients with McArdle disease between 2011 and 2019. Data relating to genotype and phenotype, including frequency of rhabdomyolysis, fixed muscle weakness, gout and comorbidities, inclusive of retinal disease (pattern retinal dystrophy) and thyroid disease, were collected. Data from 197 patients are presented. Seven previously unpublished PYGM mutations are described. Exercise intolerance (100%) and episodic rhabdomyolysis (75.6%) were the most common symptoms. Fixed muscle weakness was present in 82 (41.6%) subjects. Unexpectedly, ptosis was observed in 28 patients (14.2%). Hyperuricaemia was a common finding present in 88 subjects (44.7%), complicated by gout in 25% of cases. Thyroid dysfunction was described in 30 subjects (15.2%), and in 3 cases, papillary thyroid cancer was observed. Pattern retinal dystrophy was detected in 15 out of the 41 subjects that underwent an ophthalmic assessment (36.6%). In addition to fixed muscle weakness, ptosis was a relatively common finding. Surprisingly, dysfunction of thyroid and retinal abnormalities were relatively frequent comorbidities. Further studies are needed to better clarify this association, although our finding may have important implication for patient management.

Topics: Adult; Female; Genotype; Glycogen; Glycogen Phosphorylase, Muscle Form; Glycogen Storage Disease Type V; Humans; Male; Middle Aged; Muscle Weakness; Muscle, Skeletal; Mutation; Phenotype; Retinal Dystrophies; Retrospective Studies; Rhabdomyolysis; Thyroid Diseases; United Kingdom

Topics: Animals; Glycogen; Male; Myocardium; Rats; Thyroid Diseases; Thyroid Gland; Thyroxine