Serum electrolytes and parathyroid hormone concentrations in acute myocardial infarction

Serum concentrations of calcium, magnesium, potassium and phosphate can be lowered experimentally by adrenaline, which also can stimulate the secretion of parathyroid hormone (PTH). In order to evaluate the possible clinical importance of these mechanisms serial blood samples were drawn during the first three hospital days in 26 patients with acute myocardial infarction (AMI), a condition known to increase plasma catecholamine levels. During the study period there were no consistent significant changes of the serum electrolytes. The serum PTH levels, however, were significantly raised in the AMI patients already on admission and did not normalize during the observation time. The PTH concentrations were unexplained by infarct size, concomitant diseases or medication. These findings suggest that PTH could be an independent risk factor for AMI

Serum electrolytes and parathyroid hormone in patients in a coronary care unit

A prospective study was carried out in 499 patients admitted to a coronary care unit (CCU) in order to evaluate the incidence of clinically significant electrolyte disturbances. Low serum potassium values (less than 3.6 mmol l) occurred in 7% of the CCU patients and low serum magnesium values (less than 0.70 mmol l-1) in 6%. Few patients had low values of both these ions (1.9%). In 49 patients the contents of these electrolytes in muscle biopsies were similar to the values of control subjects and were unrelated to treatment with diuretics. Serum calcium was determined in 444 of the patients and was above the reference range in 11 (2.5%). If we consider their concomitant parathyroid hormone (PTH) values, primary hyperparathyroidism was likely to occur in at least seven patients (1.5%). Patients with acute myocardial infarction (AMI) had mean PTH and electrolyte values similar to those of individuals without this disease. In conclusion, the present study indicates that clinically important disturbances of magnesium, potassium or calcium homeostasis are rare among unselected patients admitted to a CCU

Empty Railcar Distribution

Each year in North America, approximately 30 million carloads are shipped via rail in “general merchandise” or carload service (AAR 2012). In each case, the railroad must deliver a rail-owned empty railcar (such as a box car, gondola, or hopper depending on the commodity) to the origin of the shipper to begin loading. (This process does not apply to private fleets owned and managed by the shipper, as is common for some car types such as tank cars.) After the loaded railcar is delivered to the shipper’s destination and emptied, the rail car is released back to the railroad\u27s custody, and the cycle begins again. The challenge of repositioning a multitude of rail-owned railcars to various origins is known as the empty railcar distribution problem