Serum-ionised magnesium in patients with acute myocardial infarction. Relation to cardiac arrhythmias, left ventricular function and mortality.

Measurement of serum-ionised magnesium has recently become available, and we report the first study of the relation of this parameter to arrhythmias, left ventricular function and mortality in patients with an acute myocardial infarction. Serum-ionised magnesium was determined in 217 consecutive patients admitted to hospital with an enzyme confirmed AMI. 70 healthy subjects acted as a control group. The main study parameters were occurrence of arrhythmias, left ventricular function estimated by echocardiography, and mortality after 10 months for the AMI patients. AMI patients had significantly lower serum-ionised magnesium compared to healthy controls but the level of serum-ionised magnesium in the acute phase of a MI was neither related to arrhythmias, left ventricular function nor mortality.

Measurements of mineral oil mist, hydrocarbon vapor, and noise in engine rooms of ships.

The purpose of this study was to determine the concentrations of oil mist and hydrocarbon vapor to which marine engineers are currently exposed. Measurements were also taken of the sound level in the engine room and the control rooms. Area mist concentration measurements were performed in 21 ferries, 2 cargo ships, and 1 westamaran (an express ship with two keels). Measurements were also performed for four different tasks where exposures above area level were expected. The area level of oil mist in the engine rooms of the different ships varied from not detectable to 0.53 mg/m3 (mean 0.24 mg/m3). The levels of hydrocarbons in the different ships varied from 0.2 to 14.5 mg/m3. The sound level varied from 96 to 108 dB(A) in the engine rooms, and from 70 to 90 dB(A) in the control room. When compared to other studies, it is supposed that the exposure to noise and mineral oil mist in the engine rooms of ships may represent a risk of adverse health effects for workers on Norwegian ships. The sound level may cause neurogenic hearing loss when appropriate hearing protection is not used.

Evaluation of an ionized magnesium-pH analyzer--NOVA 8.

An ion-selective analyzer (NOVA 8 [previously NOVA CRT], NOVA Biomedical Waltham, USA) for simultaneous measurement of the concentration of ionized magnesium (cMG2+) and pH is investigated for linearity and influence of calcium ions on the Mg2+ results in different Mg2+ aqueous solutions with/without added calcium. Within the cMg2+ range 0-3.0 mmol/L, which covers most clinical values, we found cMg2+ values close to the line of identity, with a sensitivity about 94%, but 0.09 mmol/L lower in the absence of Ca2+. The analytical precision (CV) for human serum control was 1.7% in the physiological range. The accuracy and precision data for the Mg2+ electrode meet the demands for reliable results within the range for clinical use. We found a reference interval (95%) for cMg2+ of between 0.43 and 0.59 mmol/L serum, with a mean value of 0.51 mmol/L for healthy adults in the non-fasting state with no relation to sex or age. The mean cMg2+ was 61% of the mean concentration of plasma total magnesium (cTMg) ranging from (95%) 49% to 73%. No significant correlation was found between cMg2+ and total protein, albumin, phosphate, Ca2+, and total CO2. No significant difference was found between mean values for cMg2+ in whole blood, plasma, and serum. Serum samples could be stored for 24 h at 4 degrees C without significant change. Storage at -20 degrees C for 7 months caused a mean cMg2+ decrease of 8.3%. The mean slope delta lgcMg2+/delta pH measured after equilibration with different pCO2 values in each serum sample from the reference population was -0.0110, indicating a close agreement between the values for actual cMg2+ and adjusted cMg2+ (pH = 7.4).