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Superoxide dismutases (SODs) are necessary antioxidant enzymes that protect cells from reactive oxygen species (ROS). Decreased levels of SODs or mutations that affect their catalytic activity have serious phenotypic consequences. SODs perform their bio-protective role by converting superoxide into oxygen and hydrogen peroxide by cyclic oxidation and reduction reactions with the active site metal. Mutations of SODs can cause cancer of the lung, colon, and lymphatic system, as well as neurodegenerative diseases such as Parkinson's disease and amyotrophic lateral sclerosis. While SODs have proven to be of significant biological importance since their discovery in 1968, the mechanistic nature of their catalytic function remains elusive. Extensive investigations with a multitude of approaches have tried to unveil the catalytic workings of SODs, but experimental limitations have impeded direct observations of the mechanism. Here, we focus on human MnSOD, the most significant enzyme in protecting against ROS in the human body. Human MnSOD resides in the mitochondrial matrix, the location of up to 90% of cellular ROS generation. We review the current knowledge of the MnSOD enzymatic mechanism and ongoing studies into solving the remaining mysteries. [ABSTRACT FROM AUTHOR]

Background One epidemiological study in Canada has addressed the association between zinc intake and depressive symptoms during pregnancy while another epidemiological study in Korea has examined the association between iron intake and depressive symptoms during pregnancy. The present cross-sectional study in Japan examined the association between intake of zinc, magnesium, iron, copper, and manganese and depressive symptoms during pregnancy. Methods Study subjects were 1745 pregnant women. Dietary intake during the preceding month was assessed using a self-administered diet history questionnaire. Depressive symptoms were defined as a score ≥16 on the Center for Epidemiologic Studies Depression Scale. Adjustment was made for age, gestation, region of residence, number of children, family structure, history of depression, family history of depression, smoking, secondhand smoke exposure at home and at work, employment, household income, education, body mass index, and intake of saturated fatty acids, eicosapentaenoic acid plus docosahexaenoic acid, calcium, vitamin D, and isoflavones. Results In crude analysis, significant inverse associations were observed between intake levels of zinc, magnesium, iron, copper, and manganese and the prevalence of depressive symptoms during pregnancy. After adjustment for confounding factors, only manganese intake was independently inversely associated with depressive symptoms during pregnancy: the adjusted prevalence ratio between extreme quartiles was 0.74 (95% confidence interval:0.56−0.97, P for trend=0.046). Limitations Information was obtained between the 5th and 39th week of pregnancy. Conclusions The current cross-sectional study of Japanese women demonstrated higher manganese intake to be independently associated with a lower prevalence of depressive symptoms during pregnancy. [ABSTRACT FROM AUTHOR]

Manganese (Mn) is a trace element required for normal physiological processes in animals and humans. Organic forms of trace elements are expected to have higher bioavailability in comparison with inorganic sources. The effect of feeding a diet supplemented with different sources of manganese to lambs was studied in a 112-d feeding trial. The aim of this study was to investigate the deposition of Mn in relation to activities of superoxide dismutase (SOD), manganese superoxide dismutase (MnSOD) and arginase in the tissues of lambs fed the diet supplemented with an inorganic or an organic source of manganese up to the maximum total Mn content allowed in the European Union (150 mg Mn/kg). A total of eighteen female lambs of the improved Valachian breed were randomly allocated to three dietary treatments and fed an unsupplemented basal diet (Control, 31 mg Mn/kg) or the identical diet supplemented with manganese sulphate (MnSO 4 ) or manganese chelate of glycine hydrate (Mn-Gly) with a total Mn content up to 150 mg/kg. Regardless of the source, feed supplementation with manganese increased Mn concentrations in plasma ( P ˂ 0.05) and the liver ( P ˂ 0.001) as well as the activity of liver MnSOD ( P ˂ 0.05) and arginase ( P ˂ 0.001) compared with the control lambs. In the kidney cortex, the concentration of Mn was greatest in lambs fed the diet supplemented with the chelated Mn source compared with animals receiving the inorganic Mn source ( P ˂ 0.05) and the unsupplemented diet ( P ˂ 0.001). The 112-d intake of feed enriched with manganese did not result in any change in Mn levels, SOD or MnSOD activity in pancreas and kidney tissues. Plasma Cu concentration was depressed in both supplemented treatments. No analyzed tissue showed a change in zinc and copper levels, except the greater Cu concentration in the liver of lambs fed the diet with Mn-Gly. The presented results did not indicate any differences between dietary Mn sources either in Mn tissue deposition or activity of SOD, MnSOD and arginase in lamb tissues; however, it seems that manganese intake of up to 150 mg/kg in feed may decrease plasma Cu concentration in lambs. [ABSTRACT FROM AUTHOR]

Manganese (Mn) is an essential trace element that is critical for human health and development. At the turn of the century when diets were based on whole grains, cereals and other traditional foods, Mn intakes (8–9 mg/d) were much greater than that prevalent today (2 mg/d). As societies have developed, diets have shifted as part of a nutrition transition, to those that are high in processed foods, fat, and sugar. These foods are virtually devoid of Mn. Thus, dietary Mn has declined substantially throughout the world, as confirmed by several wide-scale, total diet studies. International variability in dietary Mn is considerable, due to tremendous diversity in food and culture. In countries where fruit and vegetable intake may be limited, i.e. the United Kingdom, populations may ingest much lower levels of Mn (1.4 mg/d) as compared to Asian cultures (4 mg/d) which have an abundance of plant foods in their food supply and cuisine. The bioavailability of Mn must be considered, including chemical form, oxidation state, mineral-mineral interactions, presence of dietary components and traditional food processing techniques (milling, germination, malting, fermentation). Manganese toxicity is a public health problem that results from exposure to a naturally high water source or contaminated environment of the soil and/or drinking water. In contrast, inadequate intake is associated with adverse health effects such as diabetes, metabolic syndrome, poor birth outcomes and possibly, cancer. Future studies are recommended to set dietary standards for this mineral in countries that lack recommendations to help achieve optimal health. [ABSTRACT FROM AUTHOR]

This study aimed to evaluate the influence of Mn and Zn supplements (from organic sources) added to laying hens diets on egg quality. The experiment was conducted for 42 days on 192 Lohmann Brown laying hens (45 weeks old). The birds, housed in cages (2 birds/cage), were divided into 3 groups (C, E1, E2). The three diets had the same basal formulation characterized by 17.96% crude protein and 2724.31 kcal/kg metabolisable energy. The diets for the 3 groups differed by the mineral source, by the level of Mn and Zn from mineral premix, respectively. Diet C had 73 mg Mn (as Mn2O3)/kg feed and 64 mg Zn (as ZnO)/kg feed. Diet E1 used the same level of Mn (as manganese chelate of glycine hydrate with 20% Mn) and Zn (as zinc chelate of glycine hydrate with 25% Zn) as diet C. Diet E2 used two times higher levels of Mn and Zn compared to Lohmann Brown Guide Manual (200 mg Mn and 160 mg Zn/kg feed from organic sources). During this experimental study, every two weeks egg samples were collected randomly (18 eggs/group), and 6 samples of yolk, white and eggshell were formed (3 eggs/sample). The results showed that eggshell breaking strength and eggshell thickness were not significantly (P= 0.05) different between groups. The yolk samples of egg collected from E2 group, contained Zn concentrations significantly (P = 0.05) higher than in groups C, E1 respectively. [ABSTRACT FROM AUTHOR]

Objective. To determine the prevalence of dysmagnesaemia among patients admitted to a trauma intensive care unit (ICU) and to investigate whether dysmagnesaemia at admission correlated with a worse outcome. Methods. In this retrospective case study of patients admitted to a regional level 1 trauma unit, from April 2007 to November 2010, de-identified patient data were obtained from the local patient database. Patients were divided into three groups (hypomagnesaemic, normomagnesaemic and hypermagnesaemic), which in turn were divided into two subgroups (blunt and penetrating trauma). The mortality between normo- and hypomagnesaemic patients, as well as between the subgroups, was analysed using χ2 tests. The University of KwaZulu-Natal Biomedical Research Ethics Committee approved the study (BE207/09). Results. Of the 759 trauma patients studied, 10.7% were hypomagnesaemic and 1.3% were hypermagnesaemic at admission. No statistically significant difference in mortality was observed between the hypo- and normo-/hypermagnesaemic patients. Conclusion. Dysmagnesaemia is common among trauma patients admitted to the ICU, but is not necessarily correlated with a poorer outcome. [ABSTRACT FROM AUTHOR]

Iron deficiency affects approximately one-third of the world's population, occurring most frequently in children aged 6 months to 3 years. Mechanisms of iron absorption are similar to those of other divalent metals, particularly manganese, lead, and cadmium, and a diet deficient in iron can lead to excess absorption of manganese, lead, and cadmium. Iron deficiency may lead to cognitive impairments resulting from the deficiency itself or from increased metal concentrations caused by the deficiency. Iron deficiency combined with increased manganese or lead concentrations may further affect neurodevelopment. We recently showed that blood manganese and lead concentrations are elevated among iron-deficient infants. Increased blood manganese and lead levels are likely associated with prolonged breast-feeding, which is also a risk factor for iron deficiency. Thus, babies who are breastfed for prolonged periods should be given plain, iron-fortified cereals or other good sources of dietary iron. [ABSTRACT FROM AUTHOR]

The iatrogenic risks associated with excessive Mn administration in parenteral nutrition (PN) patients are well documented. Hypermanganesemia and neurotoxicity are associated with the duration of Mn supplementation, Mn dosage, as well as pathological conditions, such as anemia or cholestasis. Recent PN guidelines recommend the biomonitoring of patients if they receive Mn in their PN longer than 30 days. The data in the literature are conflicting about the method for assessing Mn stores in humans as a definitive biomarker of Mn exposure or induced-neurotoxicity has yet to be identified. The biomonitoring of Mn relies on the analysis of whole blood Mn (WB Mn) levels, which are highly variable among human population and are not strictly correlated with Mn-induced neurotoxicity. Alterations in dopaminergic (DAergic) and catecholaminergic metabolism have been studied as predictive biomarkers of Mn-induced neurotoxicity. Given these limitations, this review addresses various approaches for biomonitoring Mn exposure and neurotoxic risk. [ABSTRACT FROM AUTHOR]

Streptococcus pneumoniae requires manganese for colonization of the human host, but the underlying molecular basis for this requirement has not been elucidated. Recently, it was shown that zinc could compromise manganese uptake and that zinc levels increased during infection by S. pneumoniae in all the niches that it colonized. Here we show, by quantitative means, that extracellular zinc acts in a dose dependent manner to competitively inhibit manganese uptake by S. pneumoniae, with an EC50 of 30.2 µM for zinc in cation-defined media. By exploiting the ability to directly manipulate S. pneumoniae accumulation of manganese, we analyzed the connection between manganese and superoxide dismutase (SodA), a primary source of protection for S. pneumoniae against oxidative stress. We show that manganese starvation led to a decrease in sodA transcription indicating that expression of sodA was regulated through an unknown manganese responsive pathway. Intriguingly, examination of recombinant SodA revealed that the enzyme was potentially a cambialistic superoxide dismutase with an iron/manganese cofactor. SodA was also shown to provide the majority of protection against oxidative stress as a S. pneumoniae ΔsodA mutant strain was found to be hypersensitive to oxidative stress, despite having wild-type manganese levels, indicating that the metal ion alone was not sufficiently protective. Collectively, these results provide a quantitative assessment of the competitive effect of zinc upon manganese uptake and provide a molecular basis for how extracellular zinc exerts a ‘toxic’ effect on bacterial pathogens, such as S. pneumoniae. [ABSTRACT FROM AUTHOR]

Streptococcus pneumoniae requires manganese for colonization of the human host, but the underlying molecular basis for this requirement has not been elucidated. Recently, it was shown that zinc could compromise manganese uptake and that zinc levels increased during infection by S. pneumoniae in all the niches that it colonized. Here we show, by quantitative means, that extracellular zinc acts in a dose dependent manner to competitively inhibit manganese uptake by S. pneumoniae, with an EC50 of 30.2 µM for zinc in cation-defined media. By exploiting the ability to directly manipulate S. pneumoniae accumulation of manganese, we analyzed the connection between manganese and superoxide dismutase (SodA), a primary source of protection for S. pneumoniae against oxidative stress. We show that manganese starvation led to a decrease in sodA transcription indicating that expression of sodA was regulated through an unknown manganese responsive pathway. Intriguingly, examination of recombinant SodA revealed that the enzyme was potentially a cambialistic superoxide dismutase with an iron/manganese cofactor. SodA was also shown to provide the majority of protection against oxidative stress as a S. pneumoniae ΔsodA mutant strain was found to be hypersensitive to oxidative stress, despite having wild-type manganese levels, indicating that the metal ion alone was not sufficiently protective. Collectively, these results provide a quantitative assessment of the competitive effect of zinc upon manganese uptake and provide a molecular basis for how extracellular zinc exerts a ‘toxic’ effect on bacterial pathogens, such as S. pneumoniae. [ABSTRACT FROM AUTHOR]

Manganese is an essential nutrient for human metabolism; however, few studies have been conducted to establish the dietary recommended intake (DRI) for manganese. The purpose of this study is to provide data that can infonn the manganese intake level and address the RI by analyzing the manganese intake of 513 young Korean adults and evaluating the blood levels and estimated manganese balance of 51 selected subjects. The average age of the total subjects was 22.6 years for men and 21.6 years for women. The average daily energy intake was 1,758.50 kcal for men and 1,578.5 kcal for women. In addition, the daily manganese intake was 3,772.7 μg for men and 3,444.2 μg for women. The manganese intake of all subjects was lower than the tolerable upper intake. The manganese intake, excretion through urine and feces, retention amount, and retention rate of the selected subjects were 2,922.8 pg, 2,612.2 μg, 331.1 μg, and 6.7%, respectively, with no significant difference between men and women except urinary excretion (0.34 jig for men vs. 0.18 μg for women, p < 0.05). The manganese intake was positively related with the intakes of food, energy, protein, fat, and carbohydrate. Also, the manganese retention amount was positively related with the intakes of energy, protein, and fat. These results show that both food intake and energy intake are important factors for manganese intake and retention. [ABSTRACT FROM AUTHOR]

Abstract: In this study calcium (Ca), cadmium (Cd), copper (Cu), iron (Fe), mercury (Hg), manganese (Mn), nickel (Ni), lead (Pb), selenium (Se), and zinc (Zn) were determined in most consumed baby foods in Europe including infant formulae and solid foods and beverages (SFB). Additionally, Cd and Zn contents were determined in baby foods from the “national baskets” of four selected countries (Italy, Spain, Slovakia, and Sweden). Overall, highest element levels were found in the soy-based infant formulae. Furthermore, the assessed daily/weekly intakes of the 0–9-month-old non-breast-fed infants were compared with the current safety limits of the 10 elements here analyzed. Assessment to Cd exposure to infants consuming commercial SFB was found to exceed the limit established by the European Food Safety Authority (EFSA) of a tolerable weekly intake (TWI) of 2.5μg Cd/kg bw. Furthermore, mercury acquisition higher than the Joint FAO/WHO Expert Committee of Food Additives (JECFA) established provisional tolerable weekly intake (PTWI) of 4μg Hg/kg bw was determined for infants fed specifically with “follow on” milk infant formula. In regard to the estimated infant intakes of the non-essential (Pb and Ni) and the essential (Ca, Cu, Fe, Mn, Se and Zn) elements the values were within the safety limits. [Copyright &y& Elsevier]

The article presents an analysis of the impacts caused by the deficiency or excess of potassium, calcium and magnesium, cations that play significant role in anesthesia and intensive care. Hypokalaemia and hyperkalaemia are caused due to deficiency and excess of potassium respectively and lead to cardiac arrests, local inflammatory reaction or pain. Magnesium on the other hand is required for treating obstetrics, neuromuscular block, asthma or subarachnoid haemorrhage.

Abstract: The role of environmental factors in the etiology of neurodegenerative disorders, such as in Parkinson''s disease (PD), has become increasingly imperative for examination, as genetics can only partially account for most cases. The heavy metal manganese (Mn) falls into this category of environmental contributors, as it is both essential but also neurotoxic upon overexposure and produces Parkinsonian symptomatology. In order to understand its toxicity, this review focuses on the various aspects of improper Mn homeostasis and its consequences using the genetically amenable Caenorhabditis elegans model. Namely, the roles of Mn transporter homologs for the divalent metal transporter 1 (DMT1) will be discussed, as Mn homeostasis is initially governed by proper cellular transport. Mn dyshomeostasis can result in enhanced oxidative stress through synergistic actions of dopamine oxidation that is dependent on the C. elegans dual oxidase BLI-3. Finally, neuroprotection conferred by the antioxidant transcription factor Nrf2 (C. elegans SKN-1) may signify a potential therapeutic approach against Mn toxicity. [Copyright &y& Elsevier]

Abstract: Aims: The present study investigated the effects of ZnCl2 and MnCl2 supplementations on advanced glycation end products (AGEs) formation and AGEs-mediated endothelial cell dysfunction. Main methods: Fluorescence detection was used to monitor the Maillard reaction. Inductively coupled plasma optical emission spectroscopy was used to test cellular zinc and manganese levels. Real-time reverse transcription polymerase chain reaction and western blot were used to analyze the expression of endothelial nitric oxide synthase (eNOS), nuclear transcription factor kappa B (NF-κB), and receptor for AGEs (RAGE). Intracellular reactive oxygen species (ROS) and nitric oxide (NO) production, NOS activity were determined by fluorescent probe assay, superoxide dismutase (SOD) activity was determined by water soluble tetrazolium salt assay. Key findings: MnCl2 showed excellent inhibitory effect on AGEs formation. Primary cultured bovine aortic endothelial cells (BAECs) were exposed to AGEs for 30min, followed by trace element treatments. Cell viability and the zinc levels declined due to AGEs exposure, which were improved with the supplementations of ZnCl2 and MnCl2. Furthermore, ZnCl2 supplementation effectively enhanced intracellular NO production, elevated eNOS expression and enzymatic activity, and down-regulated NF-κB activation and RAGE expression. MnCl2 dose-dependently impaired ROS formation, down-regulated NF-κB protein expression and nuclear translocation, as well as restored Mn-SOD enzymatic capability. Significance: Our findings suggested that trace elements relevant to diabetic, such as zinc and manganese played different roles in the formation of AGEs. Both the elements benefited the AGEs-injured BAECs through different mechanisms. [Copyright &y& Elsevier]

Introduction: Chronic manganese (Mn) exposure is a health hazard associated with the mining and processing of Mn ores. Children living in an area with increased environmental exposure to Mn may have symptoms of chronic toxicity that are different from adults who experience occupational exposure. The aim of the study was to compare health outcomes in a pediatric population living near open Mn mines with a group of children from a reference area and then to develop and implement preventive/rehabilitation measures to protect the children in the mining region. Methods: After environmental assessment, a group of 683 children living in a Mn-rich region of Ukraine were screened by clinical evaluation, detection of sIgA (37 children), micronucleus analysis (56 children), and hair Mn content (166 children). Results: Impaired growth and rickets-like skeletal deformities were observed in 33% of the children. This was a significantly higher percentage than in children in the reference region (15%). The children from the Mn-mining region also had increased salivary levels of immunoglobulin A (104.4±14.2 mcg/ml vs. 49.7±6.1 mcg/ml) among the controls (p<0.05), increased serum alpha 1 proteinase inhibitor levels (4.93±0.21 g/l compared with 2.91±0.22 g/l for controls; p<0.001) and greater numbers of micronuclei in the mucous cells of the oral cavity (0.070±0.008 vs. 0.012±0.009, p<0.001). Conclusions: These findings indicate the deleterious health consequences of living in a Mn-mining area. Medical rehabilitation programs were conducted and produced positive results, but further validation of their effectiveness is required. The study provided background information to formulate evidence-based decisions about public health in a region of high Mn exposure. [ABSTRACT FROM AUTHOR]

The article explores the normal functions of magnesium and the nursing interventions as well as clinical manifestations for imbalances of the electrolyte. Magnesium is essential to ensure the proper functioning of the sodium-potassium pump and the generation of adenosine triphosphate (ATP). Aside from these, it is also important to the secretion of parathyroid hormone that influences calcium concentrations in the human body.

There is considerable evidence indicating an increase in neurodegenerative disorders in industrialized countries. The clinical symptoms and the possible mutagenic effects produced by acute poisoning and by chronic exposure to metals are of major interest. This study is a review of the data found concerning the genotoxic potential of three metals: aluminum (Al), iron (Fe) and manganese (Mn), with emphasis on their action on human cells. [ABSTRACT FROM PUBLISHER]

Aim: to study the relationship between an adequate manganese (Mn) intake and glucose, insulin levels and insulin resistance among healthy children from Madrid (Spain). Materials and methods: 573 schoolchildren between 8 and 13 years old were studied. Energy and nutrients intake (especially Mn) was calculated with a "3-day diet record". Mn intake was compared to Adequate Intakes (AI) for this mineral. Weight and height were measured and body mass index (BMI) calculated. Fasting glucose and insulin were determined and the HOMA index was calculated to establish the presence of insulin resistance in children. Results: Girls with and inadequate intake (below the 100% of the AI value) had higher insulin and HOMA values than girls with adequate AI values (equal or higher to 100% of AI). Having in mind confounding factors (energy, carbohydrates and lipids intake, BMI and age), a significant positive correlation was found between the contribution of Mn intake to AI and HOMA levels in girls. Conclusion: It seems important to ensure an adequate Mn intake in girls in order to prevent insulin resistance and diabetes type 2 in the future. [ABSTRACT FROM AUTHOR]

Concerns for potential vulnerability to manganese (Mn) neurotoxicity during fetal and neonatal development have been raised due to increased needs for Mn for normal growth, different sources of exposure to Mn, and pharmacokinetic differences between the young and adults. A physiologically based pharmacokinetic (PBPK) model for Mn during human gestation and lactation was developed to predict Mn in fetal and neonatal brain using a parallelogram approach based upon extrapolation across life stages in rats and cross-species extrapolation to humans. Based on the rodent modeling, key physiological processes controlling Mn kinetics during gestation and lactation were incorporated, including alterations in Mn uptake, excretion, tissue-specific distributions, and placental and lactational transfer of Mn. Parameters for Mn kinetics were estimated based on human Mn data for milk, placenta, and fetal/neonatal tissues, along with allometric scaling from the human adult model. The model was evaluated by comparison with published Mn levels in cord blood, milk, and infant blood. Maternal Mn homeostasis during pregnancy and lactation, placenta and milk Mn, and fetal/neonatal tissue Mn were simulated for normal dietary intake and with inhalation exposure to environmental Mn. Model predictions indicate similar or lower internal exposures to Mn in the brains of fetus/neonate compared with the adult at or above typical environmental air Mn concentrations. This PBPK approach can assess expected Mn tissue concentration during early life and compares contributions of different Mn sources, such as breast or cow milk, formula, food, drinking water, and inhalation, with tissue concentration. [ABSTRACT FROM AUTHOR]

A total of 80 dry-cured duck breasts were used in this study. The gross composition, color and textural parameters, fatty acid and amino acid profiles, macroand micromineral content, and sensory properties were analyzed. In comparison with other drycured meat products made from cuts of whole meat, dry-cured duck breast is characterized by low moisture and a higher protein content. Saturated, monounsaturated, and polyunsaturated fatty acid contents in intramuscular fat were approximately 35, 57, and 8% of the total fatty acid methyl esters, respectively. The main essential amino acids present in dry-cured duck breast were lysine and leucine, followed by valine, threonine, and isoleucine, with aspartic and glutamic acids being the most important in the nonessential fraction. Drycured duck breast proved to be a valuable source of iron, zinc, copper, and manganese (7.57, 4.66, 0.84, and 0.87 mg/100 g of edible portion, respectively), providing approximately 57, 45.2, 93, and 43.7% of the recommended daily allowances, respectively. [ABSTRACT FROM AUTHOR]

Regional whole grain cereals and millets of North Karnataka are being recognized for nutritional and unique processing qualities. The present investigation was undertaken to study antioxidant contents (polyphenol, phytic acid and trace elements) and antioxidant activity of selected regional whole grain cereals, cooked and enriched foods. Antioxidant activity of food extracts were evaluated by spectrophotometric method against stable 1, 1-diphenyl-2-picrylhydrazyl radical (DPPH). The highest polyhenol content was observed in common sorghum for whole grains and cooked. Whereas, for enriched foods the highest polyphenol was observed in foxtail millet and similar results were also observed for phytic acid. Significant reduction was observed during cooking of traditional foods for polyphenol content. The highest zinc and copper content was found to be highest in foxtail millet. The highest manganese content was observed to be in common sorghum. Antioxidant activity ranged between 5.16 to 68.67 per cent for different processed foods. The enrichment of traditional foods with added natural food ingredients not only increased the polyphenol content and radical scavenging activity but also enhanced the aesthetic quality and sensory characteristics. [ABSTRACT FROM AUTHOR]

Abstract: Background: Growing evidence suggests that excess manganese (Mn) in children is associated with neurobehavioral impairments. In Brazil, elevated hair Mn concentrations were reported in children living near a ferro-manganese alloy plant. Objectives: We investigated these children’s and caregivers’ cognitive function in relation to bioindicators of Mn exposure. Methods: In this cross-sectional study, the WISC-III was administered to 83 children aged between 6 and 12 years; the Raven Progressive Matrix was administered to the primary caregivers (94% mothers), who likewise responded to a questionnaire on socio demographics and birth history. Mn in hair (MnH) and blood (MnB) and blood lead (PbB) were measured by graphite furnace atomic absorption spectrometry (GFAAS). Results: Children’s mean MnB and MnH were 8.2μg/L (2.7–23.4) and 5.83μg/g (0.1–86.68), respectively. Mean maternal MnH was 3.50μg/g (0.10–77.45) and correlated to children’s MnH (rho=0.294, p=0.010). Children’s MnH was negatively related to Full-Scale Intelligence Quotient (IQ) and Verbal IQ; β coefficients for MnH were −5.78 (95% CI −10.71 to −0.21) and −6.72 (−11.81 to −0.63), adjusted for maternal education and nutritional status. Maternal MnH was negatively associated with performance on the Raven’s (β=−2.69, 95% CI −5.43 to 0.05), adjusted for education years, family income and age. Conclusions: These findings confirm that high MnH in children is associated with poorer cognitive performance, especially in the verbal domain. Primary caregiver’s IQ is likewise associated to Mn exposure, suggesting that, in this situation, children’s cognition may be affected directly and indirectly by Mn exposure. [ABSTRACT FROM AUTHOR]

Background: Restricted diets of Northeast India were found to be low in both zinc and manganese. Aim: To explore the possibilities of compensating for the low zinc and manganese content in restricted diet by supplementing with traditional edibles and edibles of limited popularity. Materials and Method: Concentration of these two elements in a number of edibles from Northeast India was assessed along with some traditional edibles and edibles of limited popularity. Results: Relatively high concentration of zinc and manganese were recorded in some traditional edibles and edibles of limited popularity, which when added to diabetic diet could elevate the concentration of zinc and manganese, and bring the level of these two elements close to the recommended level. Conclusion: It is suggested that, the deficiency of essential elements in the restricted diet of diabetics in Northeast India should be monitored and appropriate supplementation may be tried, preferably through some traditional edibles and edibles of limited popularity. [ABSTRACT FROM AUTHOR]

The article presents abstracts on topics related to nutrition which include the relationship of vitamin K supplementation practice to bone density among Canadian home total parental nutrition (HTPN) patients, the relationship of manganese (Mn) prescription practices to parenteral-nutrition-associated liver disease, and the relationship of high sodium intake to acute decompensated heart failure (ADHF) among ambulatory heart failure patients.

Abstract  Liver cirrhosis is a common cause of death around the world. One of its more severe complications is hepatic encephalopathy. As a consequence of liver impairment, manganese (Mn) and other substances accumulate in the brain. Astrocytic morphological changes have been found in postmortem brains of cirrhotic patients. In this study we used a model of cirrhosis induced by bile duct ligation and Mn accumulation by exposing rats to MnCl2 (1 mg Mn/ml) in their drinking water. Four experimental groups were used: Sham, Sham plus Mn treatment, BDL (bile duct ligated) and BDL plus Mn treatment. Brain Mn was measured by atomic absorption spectrophotometry in cortex, striatum and globus pallidus. Altered and normal astrocytes were counted in the same brain areas. Brain Mn was highest in rats of the BDLMn group. An increased number of altered astrocytes was found only in BDL groups, Mn did not modify this effect. No changes were found in the total number of astrocytes. According to our results, biliary obstruction induced an increase in the number of altered astrocytes since early stages of cirrhosis and Mn did not affect this effect. [ABSTRACT FROM AUTHOR]

Iron deficiency (ID) is especially common in pregnant women and may even persist following childbirth. This is of concern in light of reports demonstrating that ID may be sufficient to produce homeostatic dysregulation of other metals, including manganese (Mn). These results are particularly important considering the potential introduction of the Mn-containing gas additive, methyl cyclopentadienyl manganese tricarbonyl (MMT), in various countries around the world. In order to model this potentially vulnerable population, we fed female rats fed either control (35 mg Fe/kg chow; 10 mg Mn/kg chow) or low iron/high-manganese (IDMn; 3.5 mg Fe/kg chow; 100 mg Mn/kg chow) diet, and examined whether these changes had any long-term behavioral effects on the animals’ spatial abilities, as tested by the Morris water maze (MWM). We also analyzed behavioral performance on auditory sensorimotor gating utilizing prepulse inhibition (PPI), which may be related to overall cognitive performance. Furthermore, brain and blood metal levels were assessed, as well as regional brain isoprostane production. We found that treated animals were slightly ID, with statistically significant increases in both iron (Fe) and Mn in the hippocampus, but statistically significantly less Fe in the cerebellum. Additionally, isoprostane levels, markers of oxidative stress, were increased in the brain stem of IDMn animals. Although treated animals were indistinguishable from controls in the PPI experiments, they performed less well than controls in the MWM. Taken together, our data suggest that vulnerable ID populations exposed to high levels of Mn may indeed be at risk of potentially dangerous alterations in brain metal levels which could also lead to behavioral deficits. [ABSTRACT FROM AUTHOR]

Manganese (Mn) is a nutrient essential for regulating neurological and skeletal functions in the human body, but it is also toxic when humans are excessively exposed to Mn. Blood (or serum/plasma) and other body fluids reflect only the most recent exposure and rapidly return to within normal ranges, even when there has been a temporary excursion in response to exposure. In this context, we have been developing a non-invasive measurement of Mn stored in bone, using in vivo neutron activation analysis. Following feasibility studies, a first pilot study, using neutron activation analysis to measure Mn in the bones of the hand of ten healthy male human subjects, was conducted with the approval of the concerned research ethics boards. The participants of this study had no known history of exposure to Mn. Two volunteers were excluded from this study due to technical problems with their measurements. The inverse variance weighted mean value of Mn/Ca for the participants of this study is 0.12 ± 0.68 µg Mn/g Ca which is comparable within uncertainties with the estimated range of 0.16-0.78 µg Mn/g Ca and mean value of 0.63 ± 0.30 µg Mn/g Ca derived from cadaver data. It is recommended to investigate the use of the diagnostic technique for in vivo measurements of workers exposed occupationally to excessive amounts of Mn who could develop many-fold increased levels of Mn in bones as demonstrated through various animal studies. The technique needs further development to improve the precision of in vivo measurements in the non-exposed population. [ABSTRACT FROM AUTHOR]

Abstract: We investigate the electronic state of Mn(III) center with an integer electron spin S =2 in the manganese(III) protoporphyrin IX reconstituted myoglobin, Mn(III)Mb, by means of multi-frequency electron paramagnetic resonance (MFEPR) spectroscopy. Using a bimodal cavity resonator, X-band EPR signal from Mn(III) center in the Mn(III)Mb was observed near zero-field region. The temperature dependence of this signal indicates a negative axial zero-field splitting value, D <0. The EPR analysis shows that this signal is attributed to the transition between the closely spaced M s =±2 energy levels for the z-axis, corresponding to the heme normal. To determine the zero-field splitting (ZFS) parameters, EPR experiments on the Mn(III)Mb were performed at various temperatures for some frequencies between 30GHz and 130GHz and magnetic fields up to 14T. We observed several EPR spectra which are analyzed with a spin Hamiltonian for S =2, yielding highly accurate ZFS parameters; D =−3.79cm−1 and |E|=0.08cm−1 for an isotropic g =2.0. These ZFS parameters are compared with those in some Mn(III) complexes and Mn(III) superoxide dismutase (SOD), and effects on these parameters by the coordination and the symmetry of the ligands are discussed. To the best of our knowledge, these EPR spectra in the Mn(III)Mb are the very first MFEPR spectra at frequencies higher than Q-band in a metalloprotein with an integer spin. [Copyright &y& Elsevier]

We evaluated whether the improved esophageal radiation tolerance following Manganese Superoxide Dismutase (MnSOD)-Plasmid Liposomes was explained by improved engraftment of bone marrow-derived progenitors. C57BL/6NHsd female mice pretreated with intraesophageal MnSOD-PL were irradiated to 29 Gy to the esophagus and intravenously transplanted with marrow from male B6. 129S7-Gt (ROSA) 26S OR/J ROSA (Lac-Z+, G418-resistant) mice. After 14 days, esophagi were removed and side population and non-side population cells evaluated for donor multilineage (endothelin/vimentin/F480) positive esophageal cells. Serial intravenous transplantability was tested in second generation 29 Gy esophagus-irradiated mice. Esophagi from recipients receiving swallowed MnSOD-PL 24 h prior to irradiation demonstrated significantly increased esophageal repopulation with donor bone marrow-derived Lac-Z+, G418+, Y-probe+ multilineage cells (37.8±1.8>50 cell Lac-Z+ foci per esophagus) compared to irradiated controls (19.8±1.8) P<0.0001. Serial transfer to second-generation irradiated C57BL/6NHsd mice of intravenously injected SP or NSP first generation recipient esophagus cells was also significantly enhanced by MnSOD-PL intraesophageal pretreatment (74.4±3.6 SP-derived Lac-Z+ foci per esophagus, 48.6±5.4 NSP-derived) compared to irradiation controls (23.4±1.8 SP, 6.0±3.0 NSP), P<0.0001. Thus, intraesophageal MnSOD-PL administration enhances engraftment of marrow-derived progenitors.Gene Therapy (2008) 15, 347–356; doi:10.1038/sj.gt.3303089; published online 20 December 2007 [ABSTRACT FROM AUTHOR]

Mn2+, at 5 mM, induced a large tension development in isotonic 126 mM K+ medium in taenia coli of guinea pig, although Na+ was not contained in the external medium. The contraction by 5 mM Mn2+ in isotonic 126 mM K+, Na+-deficient medium was more sensitive to inhibition by monoiodo-acetic acid (glyceraldehyde-3-phosphate dehydrogenase inhibitor in glycolysis), but was more resistant to inhibition by 2,4-dinitrophenol (uncoupler of mitochondrial ATP production) than was the contraction by Mn2+ in hypertonic 60 mM K+, Na+-sufficient medium. Presumably, this indicates that the contraction by Mn2+ in isotonic 126 mM K+, Na+-deficient medium is dependent on energy supplied via glycolysis rather than that via aerobic metabolism in mitochondria. [ABSTRACT FROM AUTHOR]

This study evaluates iron and manganese migration from iron pans and the impact of routine meal preparation on the iron status of vegetarians. Rice and tomato sauce were cooked in iron pans. Fe and Mn quantification were done by inductively coupled plasma optical emission spectrometry. Vegetarians had their meals prepared in cast-iron cookware for 12 weeks. Tomato sauce took up more Fe and Mn than rice. Mineral transfer increased with cooking cycles. Iron anemia decreased from 32.1 to 5.3%, while the prevalence of hematologically normal individuals increased from 41 to 67.8%. Migrated Fe from cookware improves the nutritional iron status of vegetarians. [ABSTRACT FROM AUTHOR]

High-dose manganese exposure is associated with parkinsonism. Because manganese is paramagnetic, its relative distribution within the brain can be examined using magnetic resonance imaging (MRI). Herein, we present the first comprehensive study to use MRI, pallidal index (PI), and T1 relaxation rate (R1) in concert with chemical analysis to establish a direct association between MRI changes and pallidal manganese concentration in rhesus monkeys following subchronic inhalation of manganese sulfate (MnSO4). Monkeys exposed to MnSO4 at ≥ 0.06 mg Mn/m3 developed increased manganese concentrations in the globus pallidus, putamen, olfactory epithelium, olfactory bulb, and cerebellum. Manganese concentrations within the olfactory system of the MnSO4-exposed monkeys demonstrated a decreasing rostral-caudal concentration gradient, a finding consistent with olfactory transport of inhaled manganese. Marked MRI signal hyperintensities were seen within the olfactory bulb and the globus pallidus; however, comparable changes could not be discerned in the intervening tissue. The R1 and PI were correlated with the pallidal manganese concentration. However, increases in white matter manganese concentrations in MnSO4-exposed monkeys confounded the PI measurement and may lead to underestimation of pallidal manganese accumulation. Our results indicate that the R1 can be used to estimate regional brain manganese concentrations and may be a reliable biomarker of occupational manganese exposure. To our knowledge, this study is the first to provide evidence of direct olfactory transport of an inhaled metal in a nonhuman primate. Pallidal delivery of manganese, however, likely arises primarily from systemic delivery and not directly from olfactory transport. [ABSTRACT FROM AUTHOR]

FeoB is an atypical transporter that has been shown to exclusively mediate ferrous ion transport in some bacteria. Unusually the genome of the periodontal pathogen Porphyromonas gingivalis has two genes (feoB1 and feoB2) encoding FeoB homologs, both of which are expressed in bicistronic operons. Kinetic analysis of ferrous ion transport by P. gingivalis W50 revealed the presence of a single, high affinity system with a Kt of 0.31 μM. FeoB1 was found to be solely responsible for this transport as energized cells of the isogenic FeoB1 mutant (W50FB1) did not transport radiolabeled iron, while the isogenic FeoB2 mutant (W50FB2) transported radiolabeled iron at a rate similar to wild type. This was reflected in the iron content of W50FB1 grown in iron excess conditions which was approximately half that of the wild type and W50FB2. The W50FB1 mutant had increased sensitivity to both oxygen and hydrogen peroxide and was avirulent in an animal model of infection whereas W50FB2 exhibited the same virulence as the wild type. Analysis of manganous ion uptake using inductively coupled plasma-mass spectrometry revealed a greater than 3-fold decrease in intracellular manganese accumulation in W50FB2 which was also unable to grow in manganese-limited media. The protein co-expressed with FeoB2 appears to be a novel FeoA-MntR fusion protein that exhibits homology to a manganese-responsive, DNA-binding metalloregulatory protein. These results indicate that FeoB2 is not involved in iron transport but plays a novel role in manganese transport. [ABSTRACT FROM AUTHOR]

This continuing study explores the feasibility of determination of elemental concentrations in a number of leukocyte subfractions. Establishing a reliable separation method using blood of normal subjects prior to the separation and elemental analysis of blood from heart bypass patients is the first step. In addition, three blood collection vessels were compared and assessed. Instrumental Neutron Activation Analysis (INAA) using short irradiations was the technique employed. Results indicated that determination of elemental concentration was possible, in some of the leukocyte subfractions although these are in relatively small amounts. These results highlight the need for further investigation. [ABSTRACT FROM AUTHOR]

Dietary nutrient interactions are important factors to consider in the study of nutrient status and requirements. Here, the effects of dietary interactions among copper (Cu), iron (Fe), manganese (Mn) and sulfur amino acids (SAA) on blood cell characteristics and enzyme activities were observed. Male rats (n = 8) were used in a 2 × 2 × 2 × 2 factorial design and fed an AIN-93G-based diet containing dietary Cu (<1 and 5 mg/kg), Fe (10 and 35 mg/kg), Mn (10 and 50 mg/kg) and either L-cystine (LCys) or DL-methionine (DLMet). Blood was analyzed by automated hematology cell counting and by flow cytometry. Severe Cu deficiency was verified by reductions in the activities of serum ceruloplasmin (1% of control), RBC superoxide dismutase (SOD1) (14% of control), liver cytochrome c oxidase activity (25% of control) and serum extracellular SOD (SOD3) activity (20% of controls). Because Cu is required for Fe utilization, many physiologic responses that require Fe were affected by both deficiencies, including lowered blood hemoglobin (Hgb), lower RBC volume and Hgb concentration, and an increased number of reticulocytes. Cu and Fe deficiencies together worsened some conditions, i.e., lower Hgb, lower RBC Hgb, increased RBC distribution width, increased number of reticulocytes and nucleated RBC, and a higher platelet count. Increasing dietary Mn had little effect on most variables, except to reduce serum Cu when dietary Cu was adequate but not when it was low, and to reduce RBC SOD1 activity when dietary Fe was low but not when it was adequate. Hgb concentrations were higher (P < 0.002) in Cu-deficient rats fed LCys than in those fed DLMet. There was no effect in Cu-adequate rats. Hgb was higher (P < 0.004) in Fe-adequate rats fed LCys than in those fed DLMet, with no effect in Fe-deficient rats. Although the anemia of Cu deficiency in AIN-93G-fed rats was not as pronounced as that reported in rats fed the AIN-76A-based diet, other manifestations of the deficiency were prominent. KEY WORDS: copper; iron; manganese; AIN-93G diet; rats. [ABSTRACT FROM AUTHOR]

In the bakers' yeast Saccharomyces cerevisiae, high affinity manganese uptake and intracellular distribution involve two members of the Nramp family of genes, SMF1 and SMF2. In a search for other genes involved in manganese homeostasis, PHO84 was identified. The PHO84 gene encodes a high affinity inorganic phosphate transporter, and we find that its disruption resuits in a manganese-resistant phenotype. Resistance to zinc, cobalt, and copper ions was also demonstrated for pho84Δ yeast. When challenged with high concentrations of metals, pho84Δ yeast have reduced metal ion accumulation, suggesting that resistance is due to reduced uptake of metal ions. Pho84p accounted for virtually all the manganese accumulated under metal surplus conditions, demonstrating that this transporter is the major source of excess manganese accumulation. The manganese taken in via Pho84p is indeed biologically active and can not only cause toxicity but can also be incorporated into manganese-requiring enzymes. Pho84p is essential for activating manganese enzymes in smf2Δ mutants that rely on low affinity manganese transport systems. A role for Pho84p in manganese accumulation was also identified in a standard laboratory growth medium when high affinity manganese uptake is active. Under these conditions, cells lacking both Pho84p and the high affinity Smf1p transporter accumulated low levels of manganese, although there was no major effect on activity of manganese-requiring enzymes. We conclude that Pho84p plays a role in manganese homeostasis predominantly under manganese surplus conditions and appears to be functioning as a low affinity metal transporter. [ABSTRACT FROM AUTHOR]

Because manganese (Mn) is potentially toxic, and because dietary fat type may affect Mn absorption, the objectives of the current study were to determine whether diets containing very low or very high amounts of Mn and enriched in either saturated or unsaturated fats affected measures of neuropsychological and basic metabolic function. Healthy young women were fed for 8 wk each, in a crossover design, diets that provided 0.8 or 20 mg of Mn/d. One half of the subjects received 15% of energy as cocoa butter, and one half received 15% of energy as corn oil. A meal containing (54)Mn was fed after 4 wk, and subjects underwent whole-body counting for the next 21 d. Blood draws and neuropsychological tests were administered at regular intervals during the dietary periods. When subjects consumed the diets low in Mn, compared with the high Mn diets, they absorbed a significantly higher percentage of (54)Mn, but had a significantly longer biological half-life of the absorbed (54)Mn. Manganese intake did not affect any neurological measures and only minimally affected psychologic variables. These data show that efficient mechanisms operate to maintain Mn homeostasis over the range of intakes that may be encountered in a mixed Western diet. Thus, dietary intakes of Mn from 0.8 to 20 mg for 8 wk likely do not result in Mn deficiency or toxicity signs in healthy adults. [ABSTRACT FROM AUTHOR]

The estimation of the daily oral intake of manganese (Mn) can vary significantly with the method used. This study aims to compare two different approaches: the use of dietary records along with tables of the Mn contents of different foods and the parallel collection of identical aliquots which are analyzed for Mn. Dietary samples and information were collected during a 3-day dietary assessment with five participants. The average daily oral intake of Mn estimated from the dietary records and tables of Mn contents was 3.52 mg/day (S.D.=1.9), which corresponds to an exposure dose (ED) of 50.27 μg/kg body wt./day (S.D.=26.2). With a parallel collection of identical aliquots and chemical analysis, the average intake was 2.88 mg/day (S.D.=0.64) for an ED of 41.18 μg/kg body wt./day (S.D.=8.9). Thus, the use of tables gives an estimated oral dose 22% higher than the more accurate direct chemical analysis. [Copyright &y& Elsevier]

Unlabelled: Infants requiring parenteral nutrition (n = 244) were randomized to receive either 1 (group 1, n = 121) or 0.0182 micromol/kg/d (group 2, n = 123) of manganese supplementation. The whole-blood manganese and serum direct bilirubin concentrations of the infants were monitored, as was the development of cholestasis (peak serum direct bilirubin concentration >50 micromol/L). Subgroup analysis was carried out on the data of 78 infants in group 1 and 82 in group 2 who had received manganese supplementation and more than three-quarters of their total daily fluid as parenteral nutrition for >14 d. Of all the infants randomized, the high manganese group (group 1) showed a trend towards developing higher peak whole-blood manganese concentration [group 1 versus group 2: median (interquartile range): 606.0 (421.0; 1005.0) vs 566.0 (336.0: 858.0); p=0.061] and higher peak serum direct bilirubin concentration [37.0 (10.5; 122.5) vs 19.0 (8.0; 112.5); p=0.153], but the differences between the 2 groups did not reach statistical significance. The 2 groups did not differ in terms of the occurrence of cholestasis during parenteral nutrition (63/121 vs 57/123; p=0.444). Subgroup analysis of infants who had received more than three-quarters of their total daily fluid as parenteral nutrition showed, however, that the high manganese group developed significantly higher whole-blood manganese concentration [743.5 (498.0; 1211.0) vs 587.0 (438.0; 982.0); p=0.037] and serum direct bilirubin concentration [84.0 (28.0; 170.0) vs 25.5 (9.0; 117.0): p < 0.001]. Although there was no significant difference in the occurrence of cholestasis (58/78 vs 49/82; p = 0.073), more infants in the high manganese group developed a more severe degree of direct hyperbilirubinaemia, with peak serum direct bilirubin >100 micromol/L (32/78 vs 20/82; p = 0.038).Conclusion: We conclude that the pathogenesis of parenteral nutrition-related cholestasis is probably multifactorial, and that high manganese intake is a significant contributory factor. [ABSTRACT FROM AUTHOR]

Concerns exist as to whether individuals with relative manganese deficiency or excess may be at increased risk for manganese toxicity following inhalation exposure. The objective of this study was to determine whether manganese body burden influences the pharmacokinetics of inhaled manganese sulfate (MnSO4). Postnatal day (PND) 10 rats were placed on either a low (2 ppm), sufficient (10 ppm), or high (100 ppm) manganese diet. The feeding of the 2 ppm manganese diet was associated with a number of effects, including reduced body weight gain, decreased liver manganese concentrations, and reduced whole-body manganese clearance rates. Beginning on PND 77 ± 2, male littermates were exposed 6 h/day for 14 consecutive days to 0, 0.092, or 0.92 mg MnSO4/m3. End-of-exposure tissue manganese concentrations and whole-body 54Mn elimination rates were determined. Male rats exposed to 0.092 mg MnSO4/m3 had elevated lung manganese concentrations when compared to air-exposed male rats. Male rats exposed to 0.92 mg MnSO4/m3 developed increased striatal, lung, and bile manganese concentrations when compared to air-exposed male rats. There were no significant interactions between the concentration of inhaled MnSO4 and dietary manganese level on tissue manganese concentrations. Rats exposed to 0.92 mg MnSO4/m3 also had increased 54Mn clearance rates and shorter initial phase elimination half-lives when compared with air-exposed control rats. These results suggest that, marginally manganese-deficient animals exposed to high levels of inhaled manganese compensate by increasing biliary manganese excretion. Therefore, they do not appear to be at increased risk for elevated brain manganese concentrations. [ABSTRACT FROM PUBLISHER]

Abstract. Manganese is an essential trace element that is required for the activity of several enzymes. Manganese is also quite toxic when ingested in large amounts, such as the inhalation of Mn-laden dust by miners. This review examines Mn intake by way of the food supply and poses the question: Is there reason to be concerned with Mn toxicity or deficiency in free-living populations in North America? Although much remains to be learned of the functions of Mn, at present there are only a few vaguely described cases of Mn deficiency in the medical literature. Given the heterogeneity of the North American food supply, it is difficult to see the possibility of more than greatly isolated and unique instances of Mn deficiency. However, low Mn-dependent superoxide dismutase activity may be associated with cancer susceptibility, and deserves further study. There may be reasons, however, to be concerned about Mn toxicity under some very specialized conditions. Increasing numbers of young people are adopting a vegetarian lifestyle which may greatly increase Mn intake. Iron deficiency may increase Mn absorption and further increase the body-burden of Mn, especially in vegetarians. Mn is eliminated primarily through the bile, and hepatic dysfunction could depress Mn excretion and further contribute to the body burden. Would such a combination of events predispose substantial numbers of people to chronic Mn toxicity? At present, there is no definite proof of this occurring, but given the state of knowledge at the present time, more studies with longer time-frames and more sensitive methods of analysis are needed. [ABSTRACT FROM AUTHOR]

Presents a study on the effect of dephytinization of soy protein isolate on manganese absorption in adults. Study protocol; Phytic acid; Ascorbic acid; Soy formula protein isolate.

Men (n = 20) and women (n = 20) consuming a diet adequate in manganese were fed 0.037 mBq 54Mn in a test meal. Subjects were counted in a whole-body counter for 70 d to determine whole-body retention of 54Mn. Data from days 10 to 20 and from days 19 to 70 were analyzed by linear regression to calculate absorption and biological half-life. Men absorbed significantly less 54Mn than women, but the 54Mn absorbed had a longer half-life in men. Estimates of absorption were higher, and estimates of half-life were lower, when data from days 10 to 20 were used compared with days 19 to 70. There was a significant association between manganese absorption and plasma ferritin concentrations and between manganese absorption and biological half-life. We conclude that men and women differ in manganese metabolism and that such differences may be related to iron status. We also conclude that regression estimates of absorption determined by using whole-body retention curves depend on the portion of the data used. [ABSTRACT FROM AUTHOR]

The effect of dietary factors on manganese-dependent superoxide dismutase (MnSOD) activity in humans has not been studied. We longitudinally evaluated changes in MnSOD activity and other indices of manganese and iron status in 47 women during a 124-d supplementation study. Subjects received one of four treatments: placebo, 60 mg iron, 15 mg manganese, or both mineral supplements daily. Manganese supplementation resulted in significant increases in lymphocyte MnSOD activity and serum manganese concentrations from baseline values but no changes in urinary manganese excretion or in any indices of iron status. Oral contraceptive use and the stage of the menstrual cycle did not confound the use of lymphocyte MnSOD activity or serum manganese to monitor manganese status, but fat intake affected both indices. This work demonstrated that lymphocyte MnSOD activity can be used with serum manganese concentrations to monitor manganese exposure in humans. [ABSTRACT FROM AUTHOR]

Whole-body retention of 54Mn was studied in man by measurements in a sensitive whole-body counter after intake of an extrinsically labeled infant formula. Reproducible retention figures at day 10 were observed after repeated administrations to six subjects; 2.3 ± 1.1, 3.3 ± 3.1, and 2.4 ± 1.4% (̄x ± SD) for three separate occasions. Interindividual variation of manganese retention after intake of the same labeled diet was, however, shown to be substantial. Retention at day 10 was 2.9 ± 1.8% (̄x ± SD) and varied from 0.6 to 9.2% when measured in 14 healthy subjects. Large interindividual variations in rate of excretion were observed. The retention measurements for days 10-30, however, could be closely fitted to a single exponential function for each individual. The results regarding intraindividual and interindividual variation in Mn retention indicate that factors influencing Mn absorption can be identified only by repeated administrations using each subject as his/her own control. [ABSTRACT FROM AUTHOR]

Background: Manganese encephalopathy is a potential complication of parenteral nutrition. Lack of early recognition leads to unnecessary testing and to continued exposure to manganese. Methods: Case report and review of the literature. Results: We describe the clinical and imaging findings of a patient with manganese encephalopathy in whom the diagnosis was delayed due to lack of recognition of the characteristic imaging findings. Conclusion: Manganese encephalopathy has protean clinical and imaging findings that can easily be overlooked. [ABSTRACT FROM AUTHOR]

Fatigue is probably the most intriguing symptom affecting patients with chronic cholestatic disorders, in particular those with primary biliary cirrhosis. It is postulated that fatigue in patients with primary biliary cirrhosis may be associated with morphological abnormalities of the central nervous system secondary to accumulation of manganese. However, we are still far from understanding this complex issue. [ABSTRACT FROM AUTHOR]