Warren E. C. Wacker

The Magnesium-Deficiency Tetany Syndrome in Man

MAGNESIUM is second only to potassium in abundance as an intracellular cation. The whole body of a human adult contains nearly 25 gm.1 The numerous important biochemical reactions dependent upon th...

Correlation of serum magnesium levels and cardiac digitalis intoxication

Abstract A prospective study was undertaken to compare the prevalence of hypomagnesemia and hypermagnesemia in patients with cardiac digitalis toxicity and in digitalized patients without toxicity. During an 8 month period on a general medical service, there were 38 patients with “definite” or “possible” digitalis toxicity, by serial electrocardiographic studies, among 120 digitalized patients whose serum magnesium levels were obtained. Serum magnesium concentrations were measured by atomic absorption spectrometry. Hypomagnesemia was present in 21 percent of patients with and 10 percent of those without digitalis toxicity. Hypomagnesemia was not more prevalent in patients with toxicity but relatively lower serum levels of digoxin or digitoxin. The presence of hypermagnesemia was significantly greater in patients with toxicity (18 percent) than in those without toxicity (5 percent), and appeared to be related to a significantly greater prevalence of abnormal renal function in the former group. The potential value of magnesium administration in hypomagnesemic patients with cardiac digitalis toxicity warrants investigation. Caution should be exercised in the administration of magnesium sulfate to digitalis-toxic, azotemic patients who may already be hypermagnesemic.

THE BIOCHEMISTRY OF MAGNESIUM

Magnesium is the most abundant intracellular divalent cation, varying in concentration from 5 to 30 milliequivalents (mEq) per kilogram wet weight, depending upon the organism or tissue (Wacker & Parisi, 1968; Williams & Wacker, 1967). Since the discovery by Erdtmann (1927) that magnesium is an activator of mammalian alkaline phosphatase, a host of enzymes have been shown to be activated by this cation, including most of those utilizing ATP or catalyzing the transfer of phosphate. Magnesium is also an activator of systems using thiamine pyrophosphate as a coenzyme. Since ATP is required for most of the energy-requiring biological systems, including: membrane transport, amino acid activation, acetate activation, succinate activation, protein synthesis, nucleic acid synthesis, fat synthesis, coenzyme synthesis, nerve impulse generation and transmission, muscle contraction, and oxidative phosphorylation, the function of magnesium probably extends to all of these enzymes. Considerable progress has been made in defining the role of magnesium in a number of enzymes. Many have been shown to have an absolute requirement for a divalent metal cation. However, cations other than magnesium can often satisfy this requirement. Since magnesium is the most abundant intracellular cation, it is likely that the metal requirement in vivo is fulfilled by magnesium. Owing to the large number of systems in which magnesium has been shown to play a role, it is impossible to summarize them all in this brief review. Therefore, several systems that are of particular importance in terms of their biological implications or that have been studied in the greatest detail utilizing both kinetic and physical-chemical approaches have been selected for discussion.

Urinary Alkaline Phosphatase and LDH Activities in the Differential Diagnosis of Renal Disease

Excerpt Urinary alkaline phosphatase and lactic dehydrogenase (LDH) activity measurements provide specific and sensitive tools for the detection and diagnosis of urologic disease. Both the urinary ...

A general method for magnesium analysis in biological materials by atomic absorption spectroscopy

Abstract The effects of cations, anions, the type of burner, and absorbing system on the measurements of magnesium by atomic absorption spectroscopy have been investigated. A general method for the measurement of magnesium in biological material by atomic absorption spectroscopy has been developed which employs oxine to overcome interference due to phosphate.

Adventitious inhibition of yeast alcohol dehydrogenase

Abstract The inhibition of yeast alcohol dehydrogenase by N′ -methylnicotinamide has been shown to be due to contaminating silver ions present in commercial preparations of this reagent. Contamination by metal ions, which was assessed by quantitative analysis, also accounts for the inhibition of yeast alcohol dehydrogenase by semicarbazide. Purification of the reagents by removal of the metals abolished the inhibition. The existence of enzyme concentration-dependent inhibition serves as a kinetic indicator of such an adventitious inhibition.

Determination of manganese in biological materials by atomic absorption spectroscopy

Abstract A method for the measurement of manganese in biological materials using long-path atomic absorption spectroscopy is described. Interference due to anions and cations is eliminated by performing the measurements in threequarter-saturated oxine (8-hydroxyquinoline). It is simple to perform and is sensitive over the range of 0.05–1.0 μg/ml. It does not require prior extraction with organic solvents or the use of the method of additions. The overall precision is excellent. The accuracy has been established using National Burean of Standards certified standards and by comparison with an emission spectrographic method.

Man: Sapient but Gouty

Following the lead provided by Carrods remarkable intuitive synthesis of the human inborn errors of metabolism, the study of human genetic diseases has contributed much to the understanding not on...

Experimental Treatment of Poisoning Due to Ethylene Glycol and Halogenated Ethanols.

Excerpt Treatment with ethanol protects rats and monkeys from certain lethal effects of ethylene glycol that are attributed to products of enzymatic oxidation rather than to the glycol itself. In t...