Minerals, trace elements and related biological variables in athletes and during physical activity.

This review concerns various minerals (sodium, potassium, calcium, magnesium, phosphorus), trace elements (zinc, manganese, selenium, copper, iron, cobalt, iodine, chromium, fluorine, lead, cadmium) and other biological variables (nitric oxide, L-carnitine, glutamine, serum transferrin receptor, biopyrrins) in relation to hemorheologic effects, stress, immune response and infections during physical and sports activities. In athletes, macroelements in the ionized form contribute to heart and muscle contractions, oxidative phosphorylation and the synthesis and activation of enzymatic systems. Zinc (Zn) protects against the effects of increased free reactive oxygen species such as copper (Cu) and manganese (Mn) (Cu-Zn superoxide dismutases; Mn superoxide dismutase). Selenium in glutathione peroxidase protects the cardiovascular system and the muscles, and helps combat allergic and inflammatory diseases. Copper and iron are involved in many aspects of energy metabolism and are important components in the synthesis of hemoglobin, myoglobin and cytochromes. Fluorine and Cu protect the ligaments and tendons. Physical activity appears to be beneficial to urban residents who are exposed to metal pollution (lead, cadmium). The data cited in this review are often contradictory and incomplete. It is still unclear in many cases how minerals are involved in physiological changes, and much work remains.

Natural Haemophilus influenzae type b capsular polysaccharide antibodies in 412 infants and children from West Africa (Burkina-Faso) and France: a cross-sectional serosurvey.

Prior to possible introduction of large-scale vaccination programmes, an estimation and comparison of naturally acquired immunity against Haemophilus influenzae type b (Hib) was carried out in two populations of age-stratified infants and children (from birth to 14 years old) in Burkina-Faso (West Africa) (n = 206) and France (n = 206). Hib capsular polysaccharide antibodies were detected by an ELISA method. The difference in the percentages of minimum protective levels for the two populations were not significant (0.15 microg/ml) for newborns (0-1 month) but became significant as early as 2 to 3 months of age (p < 0.01) when lower levels were found among infants from Burkina-Faso. Subsequently, the percentages in both countries remained low until 11 months of age and showed no significant differences. For children between 12 and 35 months, the results > or = 0.15 microg/ml were significantly higher in France (p < or = 0.05). From 36 months, the percentage of minimum seropositivity increased in Burkina-Faso, so that the difference was no longer significant. In each country, the percentage of children with the minimum protective level varied significantly (p < or = 0.05) according to age (0-47 months). None of the children from Burkina-Faso or France had antibody levels > 1.0 microg/ml before one year of age. Thereafter, only 9.51% of French children in the 12- to 17-month age stratum and 19.2% over 4 years of age had antibody levels > 1.0 microg/ml. There were no non-detectable results for children over 4 years of age, and the means for natural detectable Hib CP antibodies were > 0.15 microg/ml for both populations. Hib invasive infections depend on climate, socioeconomic status and ethnic and genetic factors. In Burkina-Faso, the large number of infants and children under 4 years of age susceptible to Hib infections suggests that large scale vaccination programmes are needed soon after birth. However, it would first be necessary to evaluate such factors as the frequency of Hib diseases in this population.

A multicentre serosurvey on diphtheria immunity in a French population of 1004 subjects.

Diphtheria immunity was determined in serum specimens obtained in 1994 from 1004 subjects seen in emergency departments of three distant French cities. An enzyme immunoassay was used to measure serum diphtheria antitoxin concentrations according to the following criteria: (a) antitoxin < 0.01 IU/ml: susceptibility, (b) 0.01-0.09 IU/ml: basic protection, (c) > or = 0.10 IU/ml: full protection. Among these patients, 20.3% were fully susceptible to diphtheria, 30.3% had basic but doubtful protection and only 49.4% were fully protected. Protection was different by age-groups: 73.5% of the subjects under 40 years of age, 46% between 40 and 65 and 33% over 65 were fully protected. Protection decreased with increasing age (p < 0.001)and was greater for men than women after 40 years of age (p < 0.001). The results of this exploratory study indicate that the enhancement of diphtheria immunity by boosters in adult population should be reconsidered in France as well as in many industrialized countries.

An evaluation of the biological significance of aluminium in plasma and hair of patients on long-term hemodialysis.

In hemodialyzed patients, the risk of toxicity attributed to the body accumulation of aluminium (Al) justifies the need for monitoring Al in various human media. In this study, Al concentrations in the hair and plasma of 78 hemodialyzed patients with chronic renal failure and of 351 healthy volunteers were measured by electrothermal atomic absorption spectrometry with Zeeman effect. Plasma Al concentrations in patients were significantly higher than in the controls and positively correlated with time on dialysis. Hair Al levels were widely distributed with no significant distinction between patients and controls. On the subject of establishing correlation, the authors stress the importance of taking into account the kinetics of the elimination of minerals from hair. Even when this was done, in the patient group there was no statistical link between plasma and hair Al levels. Hair Al analysis is of no value as an indicator of body Al accumulation.

Magnesium, total calcium, phosphorus, copper, and zinc in plasma and erythrocytes of venous cord blood from infants of diabetic mothers: comparison with a reference group by logistic discriminant analysis.

Concentrations of magnesium (Mg), total calcium (Ca), phosphorus (P), copper (Cu), and zinc (Zn) were investigated in plasma (Pl) and erythrocytes (Erc) of venous cord blood of 44 infants of diabetic mothers (IDMs). These same concentrations plus total glycohemoglobin and fructosamine were determined at delivery in a subset of 15 mothers of these infants. Mineral results for IDMs were compared with those for 66 apparently healthy newborns. The duration of gestation in the two groups was significantly different (P < 0.001). After adjustment for gestational age, the mean (+/- SD) differences between groups were significant for birth weight, head circumference, Erc-Mg (1.71 +/- 0.17 for IDMs vs 1.76 +/- 0.15 mmol/L for control subjects), Pl-Ca (1.96 +/- 0.32 vs 2.48 +/- 0.22 mmol/L), Pl-P (1.99 +/- 0.40 vs 1.57 +/- 0.25 mmol/L), and Erc-Cu (10.9 +/- 2.41 vs 12.9 +/- 3.00 mumol/L), but not for Erc-Zn (33.0 +/- 18.3 vs 40.4 +/- 13.6 mumol/L). The variable that best discriminated between the two infant groups after adjustment for gestational age was Pl-Ca. In the 15 mothers, Pl-Mg (0.67 +/- 0.07 mmol/L) and Pl-Ca (1.66 +/- 0.21 mmol/L) concentrations were low, Pl-Zn (9.81 +/- 3.40 mumol/L) was normal, and Pl-Cu (33.5 +/- 10.7 mumol/L) was above normal. Correlations between total glycohemoglobin and mineral values of the mothers or paired IDM mineral values were not significant. The concentration of Pl-Ca was positively correlated with Erc-Cu (P < 0.001) and Pl-Cu (P < 0.05) in the comparison group newborns but not in the IDMs.

Pharmacokinetics of magnesium salts.

Due to the widespread use of magnesium (Mg) in human medicine, interest in quantitative enteral absorption rates arose more than 100 years ago. The introduction of the AAS technique and of radioisotopes has stimulated research. Slowly exchanging compartments have not, however, been accessible up until now, and the exact mechanism(s) of enteral Mg absorption is still unclear; hence, the fate of orally administered Mg cannot be followed in detail. The capacity of skeletal Mg stores varies with exogenous Mg supply, consumption, excretion and age. In otherwise healthy subjects, urine Mg levels correlate with exogenous supply. Neglecting the fact that exogenous Mg exchanges with deep Mg stores to a considerable degree, it makes sense to qualitatively study the availability of Mg compounds by relating the amount administered to the amount excreted in the urine, especially after filling deep compartments. Since renal Mg excretion patterns are known to change when tubular reabsorption capacity is exceeded or when pH alterations occur, these parameters must be monitored and taken into account at the quantitative evaluation of data.

Association between magnesium, calcium, phosphorus, copper, and zinc in umbilical cord plasma and erythrocytes, and the gestational age and growth variables of full-term newborns.

We determined reference values in umbilical cord plasma and erythrocytes for magnesium, total calcium, phosphorus, copper, and zinc, and then calculated correlations and stepwise-regression equations in 66 white full-term newborn infants (35 boys, 31 girls). Only infants meeting certain optimal criteria and benefiting from excellent maternal conditions and uncomplicated pregnancies were included. There were no significant sex-related differences at birth among the variables studied. Gestational age was positively correlated with erythrocyte zinc (P less than 0.001), and plasma calcium was positively correlated with erythrocyte copper (P less than 0.001). Plasma copper proved to be the most significant variable in the stepwise-regression equation for birth height as the dependent variable. The most significant regressors accounting for birth weight were erythrocyte zinc followed by plasma zinc.

[Copper in the normal and diabetic pregnancy and in the perinatal period]. / Le cuivre dans la grossesse normale, diabétique et en périnatologie.

A brief analysis of copper metabolism demonstrates that coeruleoplasmine, an enzyme synthesized by the liver, contains approximately 90 p. cent of the serum copper. There are major alterations of copper metabolism during pregnancy. Copper and coeruleoplasmine concentrations increase from the sixth week, reaching particularly high levels during the third trimester before returning to normal six weeks after delivery. The copper concentration in the cord serum is much lower than that of the maternal plasma. The mechanism of this placenteal transfer is unknown. There is a reserve form of copper which is specific to the fetus and the newborn, represented by the neonatal mitochondrocupreine of the liver. Elevated levels of maternal serum copper would be the result of the mobilisation of copper stocked in the liver an other tissues. The copper needs would then be increased in order to restore the reserves. Since diabetes mellitus is a major cause of maternal and perinatal complications, the first results of the serum copper obtained, in Nantes, in diabetic insulin-dependent pregnant women, in the cord blood and in newborns, are presented. A review of the current knowledge of copper in the maternal milk concludes this study.

Correlations between magnesium and heavy metals in blood and sixteen tissues of rabbits.

Spearman correlations between magnesium and heavy metals (lead and cadmium) were investigated in blood and 16 tissues of four groups of rabbits receiving different diets: I (controls), II (water with 9.66 mumols/litre of lead), III (atherogenic), and IV (atherogenic + 9.66 mumols/litre of lead). On days 1, 42 and 172 of the experiment there were no significant correlations between magnesium and lead in rabbit blood. After 25 weeks, among the 16 tissues studied only liver presented a significant positive correlation (P less than 0.01) between magnesium and lead. Correlations between magnesium and cadmium were significantly positive (P less than 0.01) in lung, liver, adrenal gland and spleen. It is thus possible that a rise in magnesium in tissues with high metabolic activity serve to combat the harmful effects of an increase in these heavy metals.

Statistical interpretation of concentrations of magnesium, zinc, calcium, potassium, cholesterols, and creatine kinase isoenzymes in men at different stages of ischemic heart disease.

We present a statistical interpretation of plasma (Pl) and (or) erythrocyte (Erc) concentrations of magnesium, zinc, calcium, potassium, and total high-density lipoprotein (HDL) cholesterol, as well as of the activity of total creatine kinase (CK) and its CK-MB isoenzyme, in 26 men with pre-infarction syndrome (PIS) and 34 men with acute myocardial infarction (MI). Discriminant analysis allowed overall comparison of both groups and determination of the most significant variables: CK and Pl-Zn. By non-hierarchical cluster analysis we defined three homogeneous subgroups among MI men, with CK, CK-MB, and Pl-Zn differing significantly between the groups. In PIS men, Pl-Zn was correlated with Pl-Ca, whereas in MI men Pl-Zn was correlated with Pl-Mg. Stepwise regression indicated that Pl-Zn was the most significant regressor of CK in PIS men and of CK-MB in MI men. All these statistical interpretations support a special role of Pl-Zn in diagnosis and perhaps prognosis. After MI, interleukin-1 release may possibly mediate observed hypozincemia via formation of a heart Zn-metallothionein.

Changes in magnesium, zinc, calcium, potassium, cholesterol, and creatine kinase concentrations in patients from pre-infarction syndrome to fatal myocardial infarction.

We measured changes in concentrations of magnesium, zinc, calcium, potassium, cholesterol [total and high-density lipoproteins (HDL)], total creatine kinase (CK), and CK isoenzyme-MB in plasma (PI) and/or erythrocytes (Erc) from apparently healthy subjects and from patients with either pre-infarction syndrome (PIS) or myocardial infarction (MI) with a favorable (MI1) or fatal (MI2) outcome, to assess the relationship of these changes to the increasing severity of ischemic disease. Significant sex-related differences led us to study men and women separately. In MI1 and MI2 patients, concentrations of Mg in PI and Erc were increased as a function of time since the infarct, confirming the cardiac Mg leaves the heart and enters the circulatory compartment. Compared with concentrations in MI2 patients, Zn concentrations in PI were lower in MI2 patients in the days before death. Significant negative correlations between Zn in PI in MI1 men or Zn in Erc in MI2 men and CK or CK isoenzyme MB suggest that circulating Zn is taken up by non-necrotic myocardial tissue as part of the repair process. MI2 patients had gradually decreasing Ca concentrations in PI even more marked than those observed in PIS and MI1 patients. We also noted a marked decrease in total and HDL cholesterol concentrations in both MI2 men and MI2 women shortly before death.

Changes in magnesium, zinc and calcium in men and women after an acute myocardial infarction.

The relations between different elements in acute myocardial infarction (MI) led us to determine erythrocyte (Erc) and/or plasma (Pl) concentrations of magnesium (Erc-Mg; Pl-Mg), zinc (Erc-Zn; Pl-Zn) and calcium (Pl-Ca) in 34 men and 8 women upon admission to hospital and then on days 2, 3, 6, 10 and 12. On day 1, these two groups were compared with 58 reference men or 53 reference women. The changes in the different variables from day 1 to day 12 were analyzed by one-way ANOVA. In MI men, from day 1 to day 12, all cations were significantly modified. In MI women, only Erc-Zn and Pl-Ca remained unchanged. In both populations, Pl-Mg, Erc-Mg and Pl-Zn increased significantly between day 1 and day 12.

Se, Zn, Mg, Ca, K, cholesterol, and creatine kinase concentrations in men during the 12 days after an acute myocardial infarction.

We determined concentrations of selenium, zinc, magnesium, calcium, potassium, total and high-density lipoprotein cholesterol, and total creatine kinase (EC 2.7.3.2) in plasma (P) and (or) erythrocytes (E) of 32 men at the time of hospital admission for acute myocardial infarction and then on subsequent days 2, 3, 6, 10, and 12. During these 12 days, only P-selenium and high-density lipoprotein cholesterol concentrations remained unchanged. For the other variables, individual comparison of means indicated the dates of significant changes in concentration (p less than 0.05).