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Biomedical subjects

T Dyckner

Publications and source records attributed to T Dyckner.

51 records · Page 3Linked to original sources

Relation between potassium, magnesium and cardiac arrhythmias.

Magnesium may influence the incidence of cardiac arrhythmias by 1) a direct effect 2) an effect on potassium metabolism 3) an effect as a calcium blocking agent. In the event of a magnesium deficiency the cell cannot attract potassium against the transmembrane concentration gradient. The reason may be that a magnesium deficiency interferes with the function of membrane ATPase, and thus the pumping of sodium out from the cell and potassium into the cell is impaired. The interference from a magnesium deficiency on the equilibrium of potassium between the intra- and extracellular spaces may result in changes in the resting membrane potential, changes in potassium conductance across the cell membrane as well as disturbances in the repolarization phase.

Aged↗

Serum magnesium in acute myocardial infarction. Relation to arrhythmias.

During 1 1/2 years, 768 patients-905 admissions, 342 with acute myocardial infarction (AMI), 563 with other diagnoses-were treated in the CCU at Serafimerlasarettet. On admission, both the AMI and the non-AMI group had significantly lower serum magnesium levels than a reference group. The incidence of serious VEBs, VT and VF on admission was significantly higher in the hypomagnesemic patients with AMI. AV blocks and SVB were more frequently observed in the hypermagnesemic patients, both in the AMI and in the non-AMI group. The incidence of AF and SVT was higher in the hypomagnesemic patients.

Aged↗

Ventricular extrasystoles and intracellular electrolytes before and after potassium and magnesium infusions in patients on diuretic treatment.

Thirty-four patients suspected of being magnesium deficient were given intravenous infusions of potassium and magnesium. The muscle contents of sodium, potassium, magnesium, and chloride were determined by atomic absorption spectrophotometry on skeletal muscle samples obtained by percutaneous biopsies. The frequency of ventricular etopic beats (VEBs) was assessed from a 3-hour ECG tape recording before the infusions and after the completion of each infusion. The potassium infusions did not result in any changes in the cellular potassium content, nor in the frequency of VEBs. After the magnesium infusions, however, a significant increase was noted in the cellular potassium content and likewise a significant decrease in the frequency of VEBs. This emphasizes the importance of magnesium in potassium metabolism.

Aged↗

Effects on muscle electrolytes of potassium and magnesium infusions, spironolactone medication and operation in a case of primary aldosteronism.

Serum and muscle electrolytes were determined in a case of primary aldosteronism before and after potassium and magnesium infusions as well as spironolactone treatment and following surgery. Repeated potassium infusions resulted in a transient normalization of the muscle potassium (K/m), followed within 3-4 days by a return to the previously low K/m. Magnesium infusions did not give any increase in muscle magnesium (Mg/m). On the contrary, there was a decrease in Mg/m concomitant with a decrease in K/m. Treatment with spironolactone for one month was followed by a normalization of both serum and muscle electrolytes. Following surgery the serum potassium and K/m remained normal, but the serum magnesium (Mg/s) and Mg/m showed a decrease to subnormal values. Despite the initial findings of normal Mg/s and Mg/m as well as excretion of more than 80% of the i.v. magnesium dose, this may indicate that there was a magnesium deficiency in the skeletal pool.

Female↗

The relation between extra- and intracellular electrolytes in patients with hypokalemia and/or diuretic treatment.

The relation between extra- and intracellular electrolytes has been studied by means of percutaneous muscle biopsies in 107 patients with hypokalemia and/or treatment with diuretics. No relation was found between the extra- and intracellular concentrations of Na or Mg. The serum and muscle contents of K correlated weakly. The correlation coefficient tended to be stronger when S-creatinine was normal, total carbonate was between 25 and 30 mmol/l, muscle Mg content was greater than or equal to 3.95 mmol/100 g fat free dry solids, and when no treatment was given with digitalis and/or diuretics.

Aged↗

Ventricular extrasystoles and intracellular electrolytes in hypokalemic patients before and after correction of the hypokalemia.

Fifty-four initially hypokalemic patients, 43 of whom were on diuretic treatment, were given potassium supplementation until they showed a repeatedly normal serum potassium level. Muscle specimens obtained by percutaneous biopsy revealed that there were no concomitant increases in muscle potassium content, nor in intracellular potassium concentration, except in the very small group (6 patients) with a muscle magnesium content of greater than or equal to 3.95 mmol/100 g fat free dry solids (FFDS) and an initially lower muscle potassium content (less than or equal to 39.9 mmol/100 g FFDS). ECG, registered for 3 hours on a portable ECG tape recorder before and after correction of the serum potassium level, showed no change in the frequency of ventricular ectopic beats.

Aged↗

Intracellular electrolytes in cardiac and skeletal muscle in fatal digitalis intoxication.

Samples from cardiac and skeletal muscle were obtained immediately after death in a case of fatal digitalis intoxication. Intra- and extracellular electrolytes were determined by atomic absorption spectrophotometry. No changes were found in the extracellular electrolytes, and only modest changes were noted in skeletal muscle. In cardiac muscle, however, profound electrolyte disturbances were recorded with an inward shift of sodium and an outward shift fo potassium. This signifies an extensive and early inhibition of the membrane ATPase in cardiac muscle and stresses the importance of immediate and vigorous treatment of the intracellular electrolyte disturbances with a view to suppressing serious and potentially lethal arrhythmias.

Chlorides↗

Familial aggregation of peptic ulcers and ischaemic heart disease. Common etiologic factors?

A family with an unexpected aggregation of both ischaemic heart disease and peptic ulcers is presented. Possible mechanisms behind an association between the two diseases are discussed. It is suggested that, depending on the genetic susceptibility, similar environmental stimuli like preexisting "stress" could induce either ischaemic heart disease or peptic ulcer.

Adult↗

Initial serum potassium level in relation to early complications and prognosis in patients with acute myocardial infarction.

During two years 450 patients with AMI have been treated in the CCU at Serafimerlasarettet. Serum potassium level was determined in 444 patients on admission. Hyperkalaemia was a rare finding associated with a bad state on admission and a poor prognosis. Hypokalaemia was recorded in 15% of the patients and was associated with previous diuretic treatment, supraventricular bradycardia as well as atrial flutter and fibrillation during the first 24 hours in the CCU. Ventricular ectopic beats and venticular tachycardia were also seen more frequently in hypokalaemic than in other patients.

Acute Disease↗

Bilateral chylothorax - complication in malignancy.

Bilateral chylothorax is a rare condition caused by traumas and disorders with perforation or destruction of main lymphatics in the thorax leading to lymph leakage. Two patients with bilateral chylothorax are presented one of whom was successfully operated on. Etiology, diagnostics and therapy of this condition are discussed.

Aged↗

Muscle magnesium and capillary basement membrane thickness in diabetes mellitus.

To evaluate a possible relationship between Mg deficiency and the development of microvascular disease in diabetes mellitus, quadriceps muscle biopsies for estimating Mg content and capillary basement membrane thickness, were studied in 16 patients with type I diabetes. The diabetic individuals had a slightly but significantly reduced muscle Mg content as compared with 13 healthy controls. There was a significant, positive correlation between capillary basement membrane width and age in the diabetic group, but no relationship between membrane thickness and muscle or serum concentration of Mg. However, diabetic patients with retinopathy (n = 6) showed a nonsignificant inverse correlation between basement membrane thickness and Mg parameters. The opposite tendency was found in patients without retinal lesions.

Adult↗