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Background: Since the emergence of the genus Homo, hominids have occupied a wide variety of environments, facing different selective pressures., Objectives: The aim this study is to compare genotype frequencies between South-West Europe and Peri-equatorial Africa in genes potentially modulators of blood pressure., Methods: The analyzed sample consisted of 325 individuals from Portugal and 226 individuals from Africa (48 from Mozambique and 178 from São Tomé and Príncipe). The following genetic variants were analyzed: intron 4 VNTR in eNOS, rs1050829 in G6PD, -3.7kb α-thalassemic deletion in HBA, rs1800457 in CYB5R3, Hp 1/2 genotype/phenotype in Hp and intron 16 I/D in ACE., Results: Frequencies of genotypes with the 4a allele in eNOS (p<0.001), the G allele in G6PD (p<0.001), the α-3.7 kb in HBA (p <0.001), the C allele in the CYB5R3 (p<0.001) were higher in Peri-equatorial Africa. The Hp 1.1 genotype of Hp has a higher frequency in Peri-equatorial Africa (p=0.002). ACE shows no significant differences., Conclusion: Results show differences in five genetic variants. Conditions of extreme heat and humidity, characteristic of Peri-equatorial Africa, have been associated with increased sodium loss. This study suggests that selected compensatory mechanisms printed in the genome, are nowadays risk factors for hypertension in Peri-equatorial Africa., (© 2021 Aguiar L et al.)

Purpose: Long-term training influence on athletes' immune cell response to acute exercise has been poorly studied, despite the complexity of both chronic and acute adaptations induced by training. The purpose of the study is to study the influence of a 4-month swimming training cycle on the immune cell response to a high-intensity training session, during 24 h of recovery, considering sex, maturity, and age group., Methods: Forty-three swimmers (16 females, 14.4 ± 1.1 years; 27 males, 16.2 ± 2.0) performed a standardized high-intensity session, after the main competition of the first (M1), and second (M2) macrocycles. Blood samples were collected before (Pre), immediately after (Post), 2 h after (Post2h) and 24 h after (Post24h) exercise. Haemogram and lymphocytes subsets were assessed by an automatic cell counter and by flow cytometry, respectively. Subjects were grouped according to sex, competitive age groups, or pubertal Tanner stages. Results express the percentage of relative differences from Pre to Post, Post2h and Post24h. Upper respiratory symptoms (URS) and training load were quantified., Results: At M2, we observed smaller increases of leukocytes (M1: 14.0 ± 36.3/M2: 2.33 ± 23.0%) and neutrophils (M1: 57.1 ± 71.6/M2: 38.9 ± 49.9%) at Post; and less efficient recoveries of total lymphocytes (M1: - 22.0 ± 20.1/M2: - 30.0 ± 18.6%) and CD19 + (M1: 4.09 ± 31.1/M2: - 19.1 ± 24.4%) at Post2h. At Post2h, the increment of CD4 + /CD8 + was smaller in youth (M1: 21.5 ± 16.0/M2: 9.23 ± 21.4%), and bigger in seniors (M1: 3.68 ± 9.21/M2: 23.2 ± 15.0%); and at Post24h late pubertal swimmers' CD16 + 56 + recovered less efficiently (M1: - 0.66 ± 34.6/M2: - 20.5 ± 34.2%)., Conclusions: The training cycle induced an attenuated immune change immediately after exercise and a less efficient recovery of total lymphocytes, involving an accentuated CD19 + decrease. The concomitant higher URS frequency suggests a potential immune depression and a longer interval of susceptibility to infection.

There is general perception that elite athletes are highly susceptible to changes in immunohematological profile. The objective of this study was to compare immunohematological parameters of elite athletes of different aerobic and muscular strength sports and analyze changes over 2 months. Sixteen judoists and 14 swimmers were evaluated 2 months before (M1) and immediately prior to competition (M2). Hemogram and lymphocytes subpopulations were assessed with automatic counter and flow cytometry, respectively. Judoists had higher neutrophils and lower monocytes and eosinophils percentages than swimmers at M1 and M2. At M2 judoists had lower red blood cells (RBC), hemoglobin, and hematocrit than swimmers. At M2 judoists' hematocrit and CD16 decreased while swimmers' hemoglobin and hematocrit increased. In conclusion, neither sports characteristics nor intense training seem to displace the athletes' immunohematological profile out of the clinical range, despite the possibility of occurrence of microlesions that may stimulate production of leukocytes and reduction of RBC in judoists.

Understanding the impact of training sessions on the immune response is crucial for the adequate periodization of training, to prevent both a negative influence on health and a performance impairment of the athlete. This study evaluated acute systemic immune cell changes in response to an actual swimming session, during a 24-h recovery period, controlling for sex, menstrual cycle phases, maturity, and age group. Competitive swimmers (30 females, 15 ± 1.3 years old; and 35 males, 16.5 ± 2.1 years old) performed a high-intensity training session. Blood samples were collected before, immediately after, 2 h after, and 24 h after exercise. Standard procedures for the assessment of leukogram by automated counting (Coulter LH 750, Beckman) and lymphocytes subsets by flow cytometry (FACS Calibur BD, Biosciences) were used. Subjects were grouped according to competitive age groups and pubertal Tanner stages. Menstrual cycle phase was monitored. The training session induced neutrophilia, lymphopenia, and a low eosinophil count, lasting for at least 2 h, independent of sex and maturity. At 24 h postexercise, the acquired immunity of juniors (15-17 years old), expressed by total lymphocytes and total T lymphocytes (CD3(+)), was not fully recovered. This should be accounted for when planning a weekly training program. The observed lymphopenia suggests a lower immune surveillance at the end of the session that may depress the immunity of athletes, highlighting the need for extra care when athletes are exposed to aggressive environmental agents such as swimming pools.

The aim of this study was to compare the redox balance in competitive adult swimmers against recreational practitioners, controlling for Mg intake. Fifteen, competitive swimmers and 16 recreational practitioners, all male and aged 18-25years, were recruited into the study. Oxidative and muscle damage markers, and antioxidant enzymes and non-enzymatic antioxidants were evaluated by photometry (except for thiobarbituric reactive substances (TBARS), which was assessed by fluorimetry). Controlling for the level of exercise, inverse correlations were observed for uric acid and glutathione reductase (GR) or susceptibility of red blood cells to peroxidation (RBCPx); plasma adrenaline oxidase activity (AdOx) and carotenoids; TBARS and GR or Vit E; and direct correlations were observed between AdOx and creatine kinase (CK) or TBARS; CK and superoxide dismutase activity; GR and RBCPx. Controlling for Mg intake in addition to exercise level revealed new inverse correlations: between carotenoids and TBARS or lactate, and new direct correlations between lactate and AdOx or TBARS; cortisol and AdOx, CK, lactate dehydrogenase, or methemoglobin reductase. The associations between uric acid and RBCPx; AdOx and CK or TBARS; and GR and RBCPx lost their significance. All others remained significant. These outcomes suggest that the coordination between antioxidant defences may be partially modulated by Mg, which may be the result of its ability to stabilize cell membranes and oxidation targets, such as adrenaline.

Adequate magnesium (Mg) levels play a vital role in membrane excitability, cell contractility and metabolism, being a key nutrient for sustaining appropriate muscular contraction and performance levels in athletes. Phase angle (PhA), assessed by bioimpedance analysis (BIA), has been reported to be positively associated with most nutritional markers and is an indicator of membrane integrity and water distribution between intra- and extracellular spaces. The aim of the present study was to verify the association between Mg status and PhA as a predictor of cellular health, in a sample of judo athletes from a period of weight stability to prior to competition. Judo athletes (n = 20) from the national team were evaluated on two occasions: during a period when body weight was stable (M1), and prior to competition (M2). Changes between these occasions were calculated as M2-M1. PhA was obtained by bioelectrical impedance spectroscopy at a frequency of 50 KHz. Mg was measured in serum and red blood cells (RBC) by atomic absorption spectrophotometry, and Mg in the diet was assessed from a 24-h diet record over a seven-day period, after an assessment of body composition. Mean PhA did not differ from M1 to M2. However, individual changes in PhA were positively associated with individual changes in serum (r = 0.62, p = 0.004) and RBC Mg (r = 0.45, p = 0.048). This association was independent of weight changes between assessments, but when adjusted for Mg intake changes, only the association between PhA and serum Mg remained significant. These results highlight that in elite athletes PhA may be an indirect indicator of muscular function.

Studies examining the immune response to acute intensive swimming have shown increased leukocytosis and lymphocyte populations. However, studies concerning mucosal immunity and sex differences remain controversial. The objective of the study was to examine sex differences on the immune response to maximal incremental swimming exercise in well trained swimmers. Participants (11 females, controlled for menstrual cycle phase effects; 10 males) performed a maximal incremental 7x200 m front crawl set. Fingertip capillary blood samples were obtained after each 200 m swim for lactate assessment. Venous blood and saliva samples were collected before and 5 minutes after the swimming test to determine total numbers of leukocytes, lymphocytes and subpopulations, and serum and salivary immunoglobulin A (IgA) levels. IgA secretion rate was calculated. Menstrual cycle phase did not influence the immune response to exercise. As for sex differences, exercise induced an increase in leukocytes, total lymphocytes, CD3(+), CD4(+), CD8(+), and CD16(+)/56(+) in males. In females, only leukocytosis, of a lower magnitude than was observed in males, occurred. CD19(+) increased and CD4(+)/CD8(+) ratio decreased in both groups following exercise whilst IgA, SIgA concentrations, and srIgA did not change. Both males and females finished the incremental exercise very close to the targeted race velocity, attaining peak blood lactate concentrations of 14.6±2.25 and 10.4±1.99 mmol.L(-1), respectively. The effect of a maximal incremental swimming task on immunity is sex dependent and more noticeable in men. Males, as a consequence of higher levels of immunosurveillance may therefore be at a lower risk of infection than females. Key PointsMaximal exercise induces an immune response.This study investigated the influence of sex over the leukocytes subpopulations and mucosal immune responses to maximal swimming.Male swimmers showed a stronger increase of T helper, T cytotoxic and NK lymphocytes than females, suggesting they may be at a lower risk of infection, due to a higher immunosurveillance.Mucosal immunity remained unchanged in both sexes.

Magnesium (Mg) deficiency has been associated with bone disorders. Physical activity is also crucial for bone mineralization. Bone mass loss has been observed to be accelerated in subjects with low Mg intake. We aim to understand if Mg intake mediates the association between bone mineral density (BMD) and lean soft tissue (LST) in elite swimmers. Seventeen elite swimmers (eight males; nine females) were evaluated. Bone mineral content, BMD, LST, and fat mass were assessed using dual energy X-ray absorptiometry. Energy and nutrient intake were assessed during a seven-day period and analyzed with Food Processor SQL. Males presented lower values than the normative data for BMD. Mg, phosphorus (P) and vitamin D intake were significantly lower than the recommended daily allowance. A linear regression model demonstrated a significant association between LST and BMD. When Mg intake was included, we observed that this was a significant, independent predictor of BMD, with a significant increase of 24% in the R(2) of the initial predictive model. When adjusted for energy, vitamin D, calcium, and P intake, Mg remained a significant predictor of BMD. In conclusion, young athletes engaged in low impact sports, should pay special attention to Mg intake, given its potential role in bone mineral mass acquisition during growth.

Magnesium plays significant roles in promoting strength. Surveys of athletes reveal that intake of magnesium is often below recommended levels. We aimed to understand the impact of magnesium intake on strength in elite male basketball, handball, and volleyball players. Energy and nutrient intake were assessed from seven-day diet record. Strength tests included maximal isometric trunk flexion, extension, and rotation, handgrip, squat and countermovement Abalakov jump, and maximal isokinetic knee extension and flexion peak torques. Linear regression models were performed with significance at p&#60;0.1. Mean magnesium intake was significantly lower than the recommended daily allowance. Regression analysis indicated that magnesium was directly associated with maximal isometric trunk flexion, rotation, and handgrip, with jumping performance tests, and with all isokinetic strength variables, independent of total energy intake. The observed associations between magnesium intake and muscle strength performance may result from the important role of magnesium in energetic metabolism, transmembrane transport and muscle contraction and relaxation.

Magnesium (Mg) deficiency strongly affects muscle performance. In judo, many athletes often undergo impressive weight changes associated with severe dehydration. Common practices used by athletes to achieve a target weight can lead to Mg deficit. This study aimed to understand the impact of Mg changes on strength from periods of weight stability to prior to competition in a sample of elite judo athletes who differentially changed their intracellular water (ICW). The sample consisted of 20 elite male judo athletes. Subjects were divided according to ICW changes: losses below 2% and losses equal to or above 2%. Mg was measured in serum, red blood cells and urine by atomic absorption spectrophotometry. ICW was calculated as the difference between total-body water and extracellular water using dilution techniques. Maximal handgrip strength was evaluated using Jamar Hydraulic Hand Dynamometer. Upper-body power was determined in a bench press. Higher ICW decreases were associated with higher strength reductions, though our results suggest that an increase in red blood cell Mg might attenuate those strength reductions in athletes who decrease the ICW compartment. As Mg losses can be considerable and intake is frequently insufficient, athletes should consider supplementation, especially during periods of weight reduction.

Objectives: Erythrocytes may play an important role in regulating blood pressure as storage sites for nitric oxide (NO). The objective of this work was to determine whether factors related to variations in erythrocyte metabolism associated with NO bioavailability, such as the activity of two enzymes--methemoglobin reductase (MHbR) and glutathione reductase (GSHR)--may help explain age-related increased blood pressure., Methods: The sample consisted of 468 individuals of both sexes, 237 hypertensive (HT) and 231 normotensive (NT), aged between 18 and 98 years (48.81 +/- 19.46). The activity of MHbR (micromol.g Hb-1.min-1) and of GSHR (micromol.g Hb-1.min-1) was determined in erythrocytes by spectrophotometry. The statistical methods used were the Mann-Whitney test, Spearman's correlation coefficient and binary logistic regression., Results: In this population, age was a risk factor for hypertension (OR=1.055, 95% CI = 1.045-1.065, p < 0.001). There was a significant difference in erythrocyte activity of these enzymes between normotensive and hypertensive subjects, with lower values in hypertensives: MHbR-NT = 16.97 (3.82-34.63), HT = 16.26 (3.26-37.10), p = 0.012; and GSHR-NT=57.60 (21.59-96.58), HT = 39.26 (23.07-90.27), p < 0.001. Enzyme activity was inversely correlated with age (MHbR: r = -0.193, p < 0.001; GSHR: r = -0.757, p < 0.001). MHbR correlated directly with GSHR only in hypertensive patients (r = 0.343, p = 0.034), which was not observed in normotensives., Conclusions: Age was a risk factor for hypertension. The erythrocyte activity of glutathione and metahemoglobin reductases, essential for redox balance and nitric oxide bioavailability in erythrocytes, may contribute only partially to the increased prevalence of age-related hypertension, and other factors should be taken into consideration, such as nutrition and antihypertensive medication.

Erythrocyte acid phosphatase (ACP locus 1), also known as low-molecular-weight protein tyrosine phosphatase, has previously been associated to glycemia, dyslipidemia, and obesity. In this study, ACP1 genotype and activity were tested in 318 women aged 19 to 83 (mean, 51.74 +/- 13.44) years. ACP1 genotype was found to directly correlate to glutathione reductase activity (P < .001) and levels of low-density lipoprotein cholesterol (P = .038). Glutathione reductase activity was in turn found to correlate to a series of cardiovascular risk factors such as systolic arterial pressure (P < .001), total cholesterol levels (P = .018), and low-density lipoprotein cholesterol levels (P = .039). A possible protective effect of ACP1 genotype AA against these cardiovascular risk factors was observed in this study. Furthermore, this work hypothesizes that nutritional riboflavin uptake becomes more crucial as body mass index increases, to counteract oxidative stress and minimize cardiovascular risk. This might be especially true in ACP1 genotypes AC, BC, and CC, which might possibly show the least endogenous protection against oxidative stress.

Physical exercise may deplete magnesium, which together with a marginal dietary magnesium intake may impair energy metabolism, muscle function, oxygen uptake and electrolyte balance. Consequently, the ability to perform physical work may be compromised. Many aspects of immune function can be depressed temporarily by either a single bout of very severe exercise or a longer period of excessive training. Although the disturbance is usually quite transient, it can be sufficient to allow a clinical episode of infection, particularly upper respiratory tract infections. However, regular and moderate exercise has been reported to improve the ability of the immune system to protect the host from infection. Magnesium also has a strong relation with the immune system in both non specific and specific immune responses and magnesium deficit has been shown to be related to impaired cellular and humoral immune function. Magnesium deficiency leads to immunopathological changes that are related to the initiation of a sequential inflammatory response. Although in athletes magnesium deficiency has not been investigated regarding alterations in the immune system, the possibility exists that magnesium deficiency could contribute to the immunological changes observed after strenuous exercise.

Background: Angiotensin-converting enzyme (ACE) I/D, haptoglobin (Hp) 1/2 and angiotensinogen (AGT) M235T gene polymorphisms have been associated with the risk of various cardiovascular conditions. Oxidative stress and reactive oxygen species have also been implicated in endothelial injury. In a randomly selected sample of healthy adolescents, we studied the relationship between these genetic polymorphisms and somatic characteristics, blood pressure and certain biochemical markers of oxidative stress., Methods: A sample of 49 healthy adolescents were genotyped for ACE I/D, Hp 1/2 and AGT M235T polymorphisms. Anthropometric parameters, blood pressure and lipid profile were evaluated using internationally recommended methods. Serum ACE activity and oxidative stress markers were determined either by spectrophotometric methods or with commercially available kits., Results: Males had higher values for ACE activity than females (p < 0.01). The haptoglobin Hp allele 1 and the ACE D allele were associated with higher ACE activity (p < 0.05 and p < 0.001). ACE activity was similar between AGT genotypes. Higher levels of MDA-LDL/Apo B were observed in individuals with both ACE DD and Hp 2-2 genotypes. Carriers of the AGT TT genotype showed higher diastolic blood pressures than other AGT genotypes., Conclusion: Carriers of both ACE DD and Hp 2-2 genotypes have a higher pro-oxidant status and AGT TT carriers have higher diastolic blood pressures, which may indicate a higher risk for development of hypertension in these individuals.

Objective: This study was conducted to determine the association between magnesium (Mg), body composition and insulin resistance in 136 sedentary postmenopausal women, 50 to 77 years of age., Methods: Diabetics, hypertensives and women on hormonal replacement therapy were excluded and the remaining 74 were divided according to BMI> or =25 (obese: OG) and BMI<25 kg/m(2) (non-obese: NOG). Nutritional data disclosed that intakes were high for protein and saturated fat, low for carbohydrates, polyunsaturated fat and Mg and normal for the other nutrients, according to recommended dietary allowances (RDA). Mg values in red blood cells (RBC-Mg) and plasma (P-Mg), were determined, as were fasting glucose, and insulin levels, Homeostasis Model Assessment (HOMA), body mass index (BMI), body fat percent (BF %), abdominal fat (AF) and free fat mass (FFM)., Results: RBC-Mg values were low in both groups when compared with normal values. There were significant differences in body composition parameters, HOMA and insulin levels, with higher basal insulin levels in OG. RBC-Mg was directly correlated with insulin, HOMA and FFM in both groups, according to Pearson correlations. HOMA in OG was also directly correlated with BMI, FFM and AF. In NOG, HOMA was only correlated with FFM. The low RBC-Mg levels observed were probably due to low Mg intake and to deregulation of factors that control Mg homeostasis during menopause., Conclusions: Both Mg deficit and obesity may independently lead to a higher risk for insulin resistance and cardiovascular disease.

The aim of this paper is to discuss, on the basis of an extensive literature review, the role of magnesium in health and disease. Magnesium is an essential cation playing a crucial role in many physiological functions. It is critical in energy-requiring metabolic processes, in protein synthesis, membrane integrity, nervous tissue conduction, neuromuscular excitability, muscle contraction, hormone secretion, and in intermediary metabolism. Serum magnesium concentration is maintained within a narrow range by the small intestine and kidney which both increase their fractional magnesium absorption under conditions of magnesium deprivation. If magnesium depletion continues, the bone store helps to maintain serum magnesium concentration by exchanging part of its content with extracellular fluid. The abundance of magnesium within cells is consistent with its relevant role in regulating tissue and cell functions. Recent data suggest that large fluxes of magnesium can cross the cell plasma membrane in either direction following a variety of hormonal and non-hormonal stimuli, resulting in major changes in total and, to a lesser extent, in free magnesium content within tissues. Imbalances of magnesium are common and are associated with a great number of pathological situations responsible for human morbidity and mortality. A large part of the population may have an inadequate magnesium intake, and in particular elderly subjects and athletes may be prone to chronic latent magnesium deficiency. Magnesium deficit is frequently observed in alcoholics and diabetic patients, in whom a combination of factors contributes to its pathogenesis. We will discuss some of the aspects of the involvement of magnesium in the etiology of some pathological situations, such as cardiovascular diseases, diabetes, pre-eclampsia, eclampsia, sickle cell disease and chronic alcoholism.

Objective: To correlate, in a sample of healthy children and adolescents, the activity of the enzyme acid phosphatase (ACP) with its different genetic phenotypes and of these with some cardiovascular risk parameters such as body mass index (BMI), percentage of total fat mass (%TFM), trunk fat (TF), insulin resistance, and the arterial blood pressure (BP)., Design and Methods: The sample was composed of 173 healthy children and adolescents, 96 (55.5%) F and 77 (44.5%) M, with ages between 10 and 16 years (mean: 13.04 +/- 1.68). The ACP activity was determined through a spectrophotometric method and its phenotypes through isoelectric focusing electrophoresis. BMI (Kg/m2) and the BP were obtained by standardized methods. Glycemia determined by the glucose oxidase method and insulinemia by RIA method. Insulin resistance based on the homeostasis model assessment (HOMA) was calculated as: [fasting insulin (microU/ml) x fasting glucose (mmol/l)]: 22.5. The %TFM and TF were determined by dual energy x-ray absorptiometry (DXA). The statistical methods used were ANOVA, the Pearson correlation and the Student's test., Results: The distribution of the phenotypes were the following--absolute versus relative frequencies: BB-74 (48.4%), AB-52 (34%), AA-16 (10.5%), BC-7 (4.6%), AC-3 (2%) and CC-1 (0.7%). ACP activities (mean: 321.04 +/- 84.56) were significantly different among the phenotypes (p < 0.001). The smallest activity was observed in the AA individuals, the highest in CC, followed by BC (247.17 +/- 66.52 and 767.30 and 362.44 +/- 91.56 respectively). Glycemia was higher in the AA individuals (4.61 +/- 0.37) compared to CC + BC (4.40 +/- 0.31) (p = 0.08). A direct correlation was verified between HOMA and BP, both diastolic (p = 0.013, r = 0.250) and systolic (p = 0.015, r = 0.246), as well as of these with BMI (mean: 20.57 +/- 3.24) and insulinemia (p = 0.016, r = 0.215; p = 0.004, r = 0.280 and p = 0.007, r = 0.240; p = 0.008, r = 0.261 respectively for diastolic and systolic BP). There were no significant difference of BMI between sexes, nor of this as well as of % TFM and TF among the different genetic phenotypes of ACP., Conclusions: The smallest enzymatic activity of ACP seems to be associated with the AA individuals, where a trend for higher glycemia was verified. BMI, HOMA and insulinemia, due to their significant direct relationship with diastolic and systolic BP in this sample of children and adolescents may warrant more future attention in the evaluation of cardiovascular risk. There were no significant differences of HOMA, BMI, %TFM, TF nor of BP among the different ACP genetic phenotypes.

Introduction: Growing evidence indicates that diet divalent cations--ionized calcium (Ca) and magnesium (Mg)--and MN blood group polymorphism may be associated with essential arterial hypertension., Objectives: To assess a possible relationship between serum ionized Ca and Mg and MN blood group polymorphism with blood pressure (BP) and body mass index (BMI)., Population and Methods: The study group consisted of 173 healthy adolescents, 96 female (55.5%) and 77 male (44.5%), with mean age of 13.0 +/- 1.7 years. Serum ionized Ca and Mg were determined by standardized methods based on detection by specific electrodes. MN blood group polymorphism was determined by immunoaglutination of erythrocytes with monoclonal antibodies. BP was evaluated based on AHA recommendations. BMI was calculated as weight divided by squared height (Kg/m2). The statistical method used was the Pearson correlation., Results: In this population no significant correlation was found from serum ionized Ca (mean: 1.07 +/- 0.06 mmol/L) and Mg (mean: 1.15 +/- 0.97 mmol/L) with systolic BP (mean: 113.1 +/- 10.7 mmHg) and diastolic BP (mean: 66.1 +/- 10.1 mmHg). In contrast there was an inverse correlation between the quotient ionized Mg/ionized Ca (0.45 +/- 0.05) and diastolic BP (p = 0.029; r = -0.381). A positive correlation was found between BMI (20.57 +/- 3.24 Kg/m2) and systolic BP (p = 0.007; r = 0.24) and diastolic BP (p = 0.016; r = 0.22). No correlation was found between ionized Ca, ionized Mg and BP with MN blood group polymorphism., Conclusions: In this population of healthy adolescents there was a dependence between diastolic BP and serum ionized Mg/ionized Ca. There was no interindividual BP and ionized Ca and Mg variation dependent from genetic variation.

Background: The aim of the present study is to evaluate the lipid profile and some parameters of oxi-redox status in a group of teenage female athletes. All gymnasts of the Portuguese National Team of Rhythmic (n=20) were included in the study. A group of untrained healthy female adolescents, matched for age, was also included (n=28)., Methods: Auxology, nutritional status and body composition were evaluated as well as biological parameters, dietary and training habits. Statistics included descriptive analysis, t-Student and Mann-Whitney for comparative study, and Pearson and Spearman correlations, according to variable distribution., Results: Chronological age was 14.3+/-1.7 and 14.6+/-1,7 years, respectively for gymnasts and untrained adolescents. Gymnasts showed lower body mass index (p<0.001) and fat mass (p<0.001) and also a hypoenergetic diet, with higher supply in protein (p<0.05) and saturated fat (p<0.01). Lipid profile showed higher HDL-cholesterol (p<0.01) and lower apo B values (p<0.001) in gymnasts, compared to untrained. Red blood cell's enzymes studied were higher for transmembrane NADH reductase of ferricyanide (TMR), (p<0.01), methaemoglobin reductase (MetHbRed), (p<0.01), and low-molecular weight protein tyrosine phosphatase (LMW-PTP), (p<0.0001) in untrained adolescents. Susceptibility of LDL to peroxidation (LDL-TBARS) were higher in gymnasts (76.3+/-20.3 microM/l versus 35+/-21.7 microM/l), (p<0.001). Correlations were positive and significant in both gymnasts and untrained, between LDL-TBARS and LDL-cholesterol (r=0.674, p<0.01 and r=0.544, p<0.05 respectively) and apolipoprotein B (r=0.721, p<0.001 and r=0.659, p<0.01, respectively). LDL-TBARS were negative and significatively correlated to TMR (t=-0.608; p<0.01) only in gymnasts., Conclusions: The authors conclude that the practice of intense physical exercise in rhythmic gymnasts induces a compromise of nutritional status and unbalanced food habits. The intensive exercise also induces not only a protective lipid profile, but also a higher lipid peroxidation. Further prospective studies are important to evaluate the influence of intensive training on atherosclerosis development.

Unlabelled: Physical exercise may in vivo promote an increase of free radical formation. Low-density lipoproteins (LDL) are highly susceptible to oxidation, probably because of their high polyunsaturated fatty acid content, since lipid oxidation is an important factor in the genesis and development of atherosclerosis. The aim of the present study is to evaluate the effect in a group of adolescent gymnasts, of intense and regular physical exercise on lipid profile and redox status., Population: All members of the Portuguese National Team of Rhythm Gymnastics (1996) (n = 20)., Methods: 1. Clinical evaluation 1.1 Anthropometric evaluation: weight, height, triceps, biceps, subscapular and supra- and supra-iliac skinfolds. NCHS were used as the standard of reference for weight and height, and Frisancho for the sum of skinfolds; 1.2. Evaluation of nutritional status (Quetelet body mass index) and body composition (Durnin and Siri). 2. Evaluation of biological parameters: a blood sample was collected after 12 hours fasting and 24 hours detraining, to evaluate: 2.1 Lipid profile: total cholesterol, high (HDL) and low (LDL) density lipoproteins, triglycerides, apolipoproteins A1 and B, were measured using internationally recommended laboratory methods; 2.2. Plasma trace elements: zinc, copper and selenium, by atomic absorption; 2.3 Red blood cell enzymes; transmembranar reductase (TMR), metahemoglobin reductase (MethaHbRed) and acid phosphatase, by spectrophotometry; 2.4. Redox status: MDA and MDA-LDL were evaluated by spectrophotometry. 3. Evaluation of eating habits: 24 hr recall., Results: Chronological age is 14.3 +/- 1.7 years. Nutritional assessment shows a mean value for height near the 50th percentile (99% +/- 3.8), and low mean values respectively for BMI (89.3% +/- 9) and sum of triceps and subscapular skinfolds (51.9% +/- 14). Study of lipid profile shows low mean values for total cholesterol (162.3 mg/dl +/- 27.7) LDL-cholesterol (87.6 mg/dl +/- 22.6) and Apo B (64.4 mg/dl +/- 11.5), but high values for HDL-cholesterol (61.3 mg/dl +/- 14.5) and Apo A1 (173.1 mg/dl +/- 25.1). We observe higher values for total cholesterol and LDL-cholesterol in those with lower Cu plasmatic levels. We also observe a negative significative correlation between MDA-LDL and Zn (r = -0.469), Cu (r = -0.524) and RTM (r = -0.608)., Conclusions: The AA concluded that in this group of gymnasts intense physical exercise induces, a favorable lipid profile, but a clear susceptibility to LDL peroxidation in those with lower plasma Cu and Zn values. It is possible that the negative correlation observed between MDA-LDL and TMR is caused by higher consumption of TMR induced by the action of exercise on the oxidative system.

The aim of the present study was to determine the effect of an aerobic training on plasma and red blood cells' levels of magnesium, copper, selenium and zinc and on some oxidative stress parameters in a Down syndrome (DS) sample population. Sixteen young male adults with DS participated in the protocol. Among them, eight were randomly assigned to the control group and the remaining eight participated in a 16 week training programme consisting of 10 min warm-up followed by an aerobic session at a work intensity of 60 to 75 per cent of VO2 peak lasting from 15 to 25 min, increasing 5 min every 5 weeks and by a 5 min cool-down period, 3 days/week. Blood was withdrawn by butterfly from antecubital vein of each subject at fast, 2 days before the beginning of the programme and 2 days after its ending. Before the training period, when comparing the two groups, no significant differences were observed in the evaluated parameters. However, when comparing with a healthy population, red blood cells magnesium and plasma and red blood cells selenium mean values were low in both groups and mean SOD activity was 1.4 times higher. After the protocol the mean values of the minerals studied did not show significant differences between groups except for plasma zinc that was lower (p = 0.029) in the trained group. Plasma TBARS increase was significant in the trained group (p = 0.034) but not in the control group and plasma GSH of the trained group had a significantly higher increase than the control group (p = 0.003). The levels of plasma TBARS after the training programme that were inversely correlated with red blood cells GSSG levels (p = 0.023) and the higher increase of plasma GSH mean values observed, may be explained by the effect of the exercise period on the peroxidation and reduction of glutathione and also on the synthesis and efflux of GSH. Red blood cells magnesium levels remained low after the training programme which is in accordance with other studies. Plasma zinc decreased during the programme could be related to the activated expression of antioxidant mechanisms after the training.

The aim of this preliminary study was to determine the relationship between exercise, magnesium (Mg) status, oxidative stress, and antioxidant defence systems. Some corresponding indices have been evaluated: plasma Mg, ascorbate, uric acid, adrenaline, creatine kinase (CK), thiobarbiturate reactive substances, adrenochrome; and in erythrocytes (RBC): reduced and oxidized glutathione (GSH and GSSG) and Mg. Venous blood samples were withdrawn before and 3 min after completion of a 40 min run. Only two significant changes were observed after effort: plasma Mg decreased (P < 0.009) and plasma adrenaline increased (P < 0.005). There was a non-significant tendency for indices of oxidative stress and antioxidant capacity to increase. The significant correlations between plasma Mg and CK (r = -0.88) and between RBC Mg and plasma ascorbate (r = -0.76) disappeared after the effort. Further research is necessary, with a larger number of subjects and variables, to obtain a better understanding of these interactions.

Erythrocyte, plasma and urinary magnesium were observed in a group of 8 well-trained swimmers and in a group of 10 untrained subjects before, 2 minutes after and 30 minutes after a swimming test. After effort, plasma Mg (pMg) decreased significantly in both groups. Erythrocyte and urinary Mg variations were not significant in this study. PMg decrease after effort was more important in the swimmers group than in the untrained group (12% versus 6% after 2 minutes; 21% versus 4% after 30 minutes). The observed fall in plasma Mg concentration after exercise cannot be explained by a shift into erythrocytes during exercise, since the Mg content of these blood cells did not suffer significant alterations. The possible causes of the observed phenomena are discussed.

The effect of a 30 min. swimming exercise (freestyle) on plasma magnesium and other biochemical variables was assessed on 6 well trained swimmers. Blood samples were taken before, right after, 30 min. and 24 hours after exercise. Serum Mg concentration decreased significantly during exercise, returning to base line 24 hours after. Erythrocyte content in Mg did not show any significant changes. Plasma total cholesterol level decreased significantly 30 min. after exercise. A significant positive correlation found at rest between plasma Mg levels and plasma total H.D.L. cholesterol disappeared after exercise but was observed again 24 hours later.

The therapeutic efficacy of Mg lactate in 35 patients (4 men and 31 women) suffering from mitral valve prolapse (MVP) and latent tetany attributed to a primary Mg deficit has been studied. The trial undertaken lasted for 16 weeks. 24 patients took Mg lactate during the entire period. In the remaining 11 patients, the trial was divided into two periods of 8 weeks each. During the first period, a placebo was administered; during the second half the patients took the Mg lactate in the same dosage as the other group. The results appear quite favorable particularly in relation to the functional manifestations and in regard to palpitations, atypical precordialgias, peripheral vascular spasms (Raynaud), muscular cramps, and lipothymias. The sign of Trousseau disappeared in the 10 cases in whom it was positive. The patients who were given a placebo during the first 8 weeks of the trial did not show any improvement. However, in the following 8 weeks during Mg lactate therapy, a regression in the symptomatology was noticed. Out of the 24 patients who underwent 16 weeks of treatment with Mg lactate, 29.2% became asymptomatic between the 4th and 12th weeks, in 45.8% one or two symptoms of a psychic nature persisted (e.g. anxiety, depressive tendency), and the remaining 25% showed an improvement, albeit, a less marked one. The auscultatory signs of MVP did not change. A tendency towards a rise in serum levels was noted during the study and was attributed to the action of Mg lactate.(ABSTRACT TRUNCATED AT 250 WORDS)

Serum (s-Mg) and red blood cell (e-Mg) Mg levels were assessed in 29 patients with acute myocardial infarction (AMI) and in 16 patients with unstable angina (UA), from admission until discharge. The following results were found: (1) no significant difference existed between mean s-Mg levels in AMI and UA, despite a tendency for an increase being noted with a favorable course of disease, (2) in AMI, mean s-Mg levels were initially lowered, increased within the first 24 h (p less than 0.05), decreased sharply at day 4 (p less than 0.05), and increased again until discharge (p less than 0.05). (3) in UA; the increase in mean e-Mg during hospitalization is statistically significant (p less than 0.02); (4) no significant difference was found between Mg levels and arrhythmias; and (5) a linear inverse correlation was found between Mg levels and prognosis of infarction.

A rise of serum Mg levels was observed in patients at 3 and 6 months after acute myocardial infarction, irrespective of therapeutic regimen. In unstable angina follow-up, serum Mg levels remained stable, but below normal values (normal mean values = 2.1 +/- SD 0.4 mg%). A significant difference between mean Mg levels at 6 months was noted in patients with unstable angina treated with calcium antagonists and nitrites as well as in patients treated only with nitrites (p less than 0.02).