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Numerous epidemiological, experimental and clinical studies over the last 30 years have consistently shown that chronic magnesium deficiency is associated with and/or exacerbates a number of major disorders (Table 1). Yet chronic magnesium deficiency is not widely recognized and a major reason for this failure is that serum magnesium levels do not accurately reflect body magnesium stores. Specifically, in chronic magnesium deficiency, serum magnesium levels are often within the normal reference range (usually lowest quartile) and may not progress to overt hypomagnesaemia. This raises serious questions namely (i) should chronic magnesium deficiency be considered in high-risk patients irrespective of serum magnesium, even when 'normal'? and (ii) if recognized, should oral magnesium supplement be given to restore body stores? Appreciating the vital role of magnesium for normal cellular function and bone health may help in formulating a well-considered and justifiable approach to these questions. Pragmatic tests for assessing magnesium status in the adult are suggested and discussed.

PURPOSE: Heavy metals and other elements may act as breast carcinogens due to estrogenic activity. We investigated associations between urine concentrations of a panel of elements and breast density. METHODS: Mammographic density categories were abstracted from radiology reports of 725 women aged 40–65 years in the Avon Army of Women. A panel of 27 elements was quantified in urine using high resolution magnetic sector inductively coupled plasma mass spectroscopy. We applied LASSO (least absolute shrinkage and selection operator) logistic regression to the 27 elements and calculated odds ratios (OR) and 95% confidence intervals (CI) for dense versus non-dense breasts, adjusting for potential confounders. RESULTS: Of the 27 elements, only magnesium (Mg) was selected into the optimal regression model. The odds ratio for dense breasts associated with doubling the Mg concentration was 1.24 (95% CI 1.03–1.49). Doubling the calcium-to-magnesium ratio was inversely associated with dense breasts (OR 0.83, 95% CI 0.70–0.98). CONCLUSIONS: Our cross-sectional study found that higher levels of urinary magnesium were associated with greater breast density. Prospective studies are needed to confirm whether magnesium as evaluated in urine is prospectively associated with breast density and, more importantly, breast cancer.

In the 1950s and 1960s, several inherited disorders of fluid and electrolyte metabolism were described in which the principal disturbance appeared to be a specific functional defect in the renal tu...

To the Editor: We report two cases of hypomagnesemic hypoparathyroidism associated with the use of proton-pump inhibitors, in which patients presented with carpopedal spasm in association with severe hypomagnesemia and hypocalcemia without an appropriate increase in the level of parathyroid hormone. Patient 1 was a 51-year-old premenopausal woman who had been taking omeprazole for more than a year (at a dose of 20 mg twice daily) and who presented with carpopedal and truncal spasm. She began receiving 2.4 g of elemental calcium per day and, later, high-dose magnesium (Figure 1A). Fourteen months later, omeprazole was discontinued, and ranitidine initiated. The . . .

Objective To examine the effectiveness of bladder washouts in reducing catheter encrustation. Materials and methods A model of the catheterized bladder was developed and used to produce catheter encrustation in vitro. The effects of bladder wash-outs with Suby G, mandelic acid 1% or saline 0.9% were compared with control catheters that did not receive wash-outs, by measuring the area of patent catheter lumen and the changes in urinary calcium and magnesium concentrations after wash-outs. Results Encrustation was reduced significantly, compared with the controls, in catheters washed out with the acidic reagents, Suby G and mandelic acid. Saline wash-outs did not reduce encrustation. Conclusion The model of the catheterized bladder provided a reliable technique with which to examine the effects of bladder wash-out on catheter encrustation under controlled conditions. The results indicate that bladder wash-outs with Suby G or mandelic acid may be beneficial for patients who suffer from recurrent catheter encrustation and blockage.

Magnesium imbalance is clinically significant. It is common, treatable, and frequently overlooked. We review the literature describing magnesium deficit and excess syndromes and formulate specific treatment protocols.

On the basis of almost 15 years of experience with thiazide treatment in 346 patients with calcium stones, we believe that the following conclusions are justified: 1) Stone progression ceases in at least 90% of patients who take hydrochlorothiazide (50 mg, twice daily) on a regular basis. 2) A reduced dose of hydrochlorothiazide, i.e., 25 mg twice daily, appears to be effective in a significant proportion of patients. 3) Thiazides are effective in normocalciuric as well as hypercalciuric patients and in most patients with tubular ectasia (medullary sponge kidney). 4. Side effects necessitate discontinuation of thiazide treatment in approximately 7% of patients. The incidence and severity of side effects is reduced by initiating treatment with a small dose and by increasing the dose progressively until the full maintenance dose is achieved. A trial with a reduced dose is warranted in patients who are unable to tolerate the regular maintenance dose. 5) The therapeutic efficacy of thiazides in stone prevention cannot be accurately predicted by the degree of hypocalciuric response. Stone prevention may cease despite a minimal hypocalciuric response, whereas stone progression may occur when an adequate hypocalciuric response has taken place. 6) In addition to the hypocalciuric action, thiazides reduce urine oxalate excretion and increase urine zinc and (probably) magnesium; these effects probably contribute to the efficacy of this agent in stone prevention.

Medical therapy is an effective method of canine struvite urolith dissolution. Recommendations include (1) eradication or control of urinary tract infection (if present), (2) use of calculolytic diets, and (3) administration of urease inhibitors to patients with persistent urinary tract infection caused by urease-producing microbes.

Current theories of renal stone formation are reviewed, together with the resulting proposals for treatment, with emphasis on the idiopathic, recurrent formation of calcium oxalate stones. Factors influencing the initiation and development of stones are discussed.

Atomic absorption spectrophotometry was evaluated as a method for the determination of calcium and magnesium in serum, urine, diet, and stool, and was found a most suitable technic for a large clinical chemistry laboratory.

A family of four siblings is reported. While both parents and one sib appear entirely normal, three other sibs give biochemical evidence of impaired potassium conservation, hypomagnesaemia and decreased urinary calcium output. Affected sibs may be symptom free and of either sex. The dominant clinical abnormality, when it does occur, is tetany and may be precipitated by non-specific illness. Sustained management of the hypokalaemia seems desirable.

Resume Des dosages de magnesium plasmatique, erythrocytaire et urinaire ont ete effectues chez 85 asthmatiques jeunes et compares aux memes dosages chez 20 sujets temoins. Aucune difference n'a ete notee dans les deux series. Ces resultats sont discordants avec certains travaux francais et etrangers et peuvent tenir a des variations geographiques, raciales, alimentaires des populations etudiees. Il est possible que les mecanismes d'action du magnesium a l'echelon cellulaire chez l'allergique n'aient pas de retentissement sur les taux sanguins de cet ion.

A 13-year-old girl had hypoparathy Summary roidism which was refractory to therapy with high doses of vitamin D 2 (given orally and intramuscularly), dihydrotachysterol (' A.T. 10 ') treatment, and up to 8 g. per day of calcium-salt supplement. The patient responded convincingly when 25 meq. of magnesium per day was given in addition to moderate oral doses of vitamin D 2 .

Daily administration of a proprietary magnesium and aluminum hydroxides suspension, 15 ml four times a day, to normal adult volunteers resulted in a statistically significant increase in urine pH on the 1st day of treatment. The urine pH's on the 2nd and subsequent days of treatment were statistically significantly higher than on the 1st day. A 7.5-ml dose of the antacid suspension, taken four times a day, had only a small and not statistically significant effect on urine pH, while 30 ml four times a day increased urine pH by approximately the same magnitude as the 15-ml doses. The effect of the antacid on urine pH persisted for at least 1 day after discontinuation of dosing.

Although actinomycin D is a relatively old cytotoxic agent, relatively little is known about its toxicity in man in comparison with some of the newer cytotoxic agents that have been extensively investigated. We wish to describe a case where an overdose of actinomycin D was inadvertently administered.

Long term administration of common loop or distal tubular diuretics may cause somatic magnesium depletion. The resultant deficiency of Mg++ destabilises the myocardium electrically and is a principal cause of cardiac arrhythmias ascribed to diuretics. The adverse effects of diuretics caused by Mg++ depletion can be avoided by selecting diuretics that do not cause magnesium deficiency, minimising the diuretic dose, supplementation of Mg++ intake, or the concomitant use of a K+-retaining, Mg++-sparing diuretic.

Crystalluria results from oversaturation of urine with crystallogenic substance. However, oversaturation may occur as a result of in vitro as well as in vivo events. The microscopic appearance of crystals only represents a tentative identification of their composition because variable conditions associated with their formation, growth, and dissolution may alter their appearance. Definitive identification is dependent on physical methods such as optical crystallography, x-ray diffraction, and electron microscopic analysis.

Summary A rapid titrimetric method for the determination of calcium and magnesium is described. The method is accurate to within 5 per cent.

Urinary magnesium excretion was evaluated during the administration of magnesium salts into one leg vein of the chicken by means of the Sperber technique. Changes of magnesium excretion paralleled those of filtered load and sustained unilateral differences of magnesium excretion were not observed. Corrected magnesium-inulin clearance ratios rose to values of approximately 1.0 and remained at that level despite continuing rises of filtered load. The results indicate that magnesium excretion is determined solely by glomerular filtration and tubular reabsorption. Evidence of a tubular secretory system was not obtained.

A number of reports of magnesium (Mg) disturbances in newly born and older infants have appeared in the last decade. The most dramatic instances have been infants who were both hypomagnesemic and hypocalcemic and whose symptoms and biochemical disturbances responded only to the administration of Mg salts. The advent of atomic absorption spectrophotometry1as a direct, relatively simple, accurate method of measuring Mg with very small specimens has reinforced interest in neonatal Mg physiology and pathology. In the present review, data drawn from many sources have been collected to synthesize and classify this growing body of information. Physiology of Magnesium Distribution and Importance.—Magnesium is the second most common intracellular cation. About one half of body Mg is in bone, one quarter in muscle, and the remainder is in other soft tissues. Normal serum Mg levels in newly born infants2-4are similar to those in children2,5and