Human Manganese Research Articles

Developing an ACURE to Investigate the Effects of Manganese on Physiological Processes

To engage freshman college students in research and STEM, we will utilize an authentic course-based undergraduate research experience (ACURE) approach through a focused research project. Introducing students to novel research projects within a course setting provides a structured way to expose participants to the process of scientific research. Involvement in the design and implementation of an experiential paradigm promotes creativity among students and encourages them to become more engaged. Through the process of gathering and analyzing data, students will gain a realistic perspective of scientific research. For this class project, we chose to focus on studying the effects of manganese on behavior, neural function and cardiovascular physiology of Drosophila melanogaster larvae and crayfish models. Emerging research has repeatedly demonstrated that overexposure to manganese in humans can lead to acute cardiovascular disorders and a series of symptoms manifesting in a manner similar to that of Parkinson's disease (PD). We have designed the class in order to gain a multifaceted understanding of these effects. To do so, the students will first examine larval crawling rate, mouth hook movement rate, and touch sensitivity of control larvae and larvae exposed to a maximum non-lethal dose of manganese in order to analyze the effect that manganese has on the behavior of D. melanogaster. Then, students will use optogenetics to activate and inactivate dopaminergic neurons in order to compare behavioral responses of the control group to the group exposed to manganese. In doing so, they will be able to gain understanding of another method of scientific investigation and further build upon the variety of data found throughout the study. Manganese also has the potential to block voltage-gated calcium channels of the heart, so the students will additionally study the effect of manganese exposure on D. melanogaster heart rate and rhythmicity in order to demonstrate the effect that manganese can have on other areas of the body. Finally, students will study the synaptic transmission at glutamatergic neuromuscular junctions by observing and recording data from the muscle fibers of both larval D. melanogaster and crayfish. Like the heart, these neuromuscular junctions contain voltage-gated calcium channels, so the students will be able to further explore the various effects of manganese exposure. The utilization of crayfish in this study will allow the students to gain a new perspective of the effect of manganese because of the ability to record crayfish action potentials intracellularly, something that is not possible to study in D. melanogaster. Overall, we believe that this student-driven research approach will promote student engagement and foster a deeper understanding of the scientific process while also widening the breadth of knowledge in the research field.

Predictive Statistical Model for Indoor Manganese Airborne Particles Affected by Psychrometric Parameters

Commonly, there are varieties of indoor airborne particles in the foundry factories. One of the main particle with emphasize on health effect on exposed human is manganese airborne particle. The current study considered correlation between indoor psychrometric parameters and manganese concentration in the workplace. Overall, fifty samples were collected by filter based on OSHA ID-121method in the workplaces. SPSS V.20 was used to find a predictive model using linear regression model. The mean personal exposure to manganese was 1.626 mg/m . The mean measured psychrometric parameters for dry temperature, relative 3 humidity and air velocity were 29°C, 52% and 1.2m/s, respectively. The correlations between personal exposures and indoor air parameters measurements showed a high significant relationship between personal exposure, dry temperature and wind speed in the factory (P< 0.05). This study concluded that controlling dry temperature and air velocity is the main effective parameters on airborne manganese concentration in the workplaces and decreased the personal exposure.

Ambient Manganese Exposure is Negatively Associated With Human Sperm Motility and Concentration

Occupational and experimental animal studies indicate that exposure to high levels of manganese impairs male fertility, but the effects of ambient manganese in humans are not known. We measured blood levels of manganese and selenium in 200 infertility clinic clients in a cross-sectional study. Correlations between metals and semen variables were determined, adjusting for other risk factors. Outcomes were low motility (<50% motile), low concentration (<20 million/mL), or low morphology (<4% normal). We also investigated dose-response relationships between quartiles of manganese exposure and sperm parameters. High manganese level was associated with increased risk of low sperm motility (odds ratio = 5.4; 95% confidence interval = 1.6-17.6) and low sperm concentration (2.4; 1.2-4.9). We saw a U-shaped dose-response pattern between quartiles of manganese exposure and all 3 sperm parameters. Ambient exposure to manganese levels is associated with a reduction in sperm motility and concentration. No adverse effects were seen for high selenium.

Speciation and toxicological relevance of manganese in humans

Although manganese is an essential trace element, concerns are rising about the Mn exposure of humans being related to neurotoxic effects. This review summarizes several aspects of this topic to provide updated information on Mn related investigations, including chemical speciation of Mn-compounds. The paper starts with some chemical aspects of Mn and its compounds, enlightening oxidation states in general and in biological matrices. This is followed by considerations on natural sources of human exposure, on occupational sources and on anthropogenically caused environmental sources, for example from the use of methylcyclopentadienyl manganese tricarbonyl (MMT). Next, the paper deals with Mn levels in the human organism, showing normal Mn concentrations in various tissues or body fluids, and continues with the toxicology of Mn, i.e. absorption, distribution and excretion. Of specific concern is the transfer of Mn to the brain which is the relevant neurotoxic target. In this context, parallels and differences between primary and Mn-dependent Parkinsonism are discussed, concluding with a risk assessment and a consideration of susceptible groups. The main part of this review focuses on recent investigations on Mn speciation. Analytical problems and their solutions are also described for correct identification of relevant Mn-compounds in matrices of human origin. Finally, future needs are discussed, such as further investigations on those Mn-species which may overcome neural barrier control, on disease-modulated barrier control, on susceptibility to certain Mn-species, and on the interaction of Mn with Fe-homeostasis in the brain.

Neurologic effects of manganese in humans: a review.

Manganese, which enters the body primarily via inhalation, can damage the nervous system and respiratory tract, as well as have other adverse effects. Occupational exposures occur mainly in mining, alloy production, processing, ferro-manganese operations, welding, and work with agrochemicals. Among the neurologic effects is an irreversible parkinsonian-like syndrome. An estimated 500,000 to 1.5 million people in the United States have Parkinson's disease, and physicians need to consider manganese exposure in its differential diagnosis. Since 1837, there have been many reports of cases and case series describing manganese toxicity. More recently, there have been epidemiologic studies of its adverse effects on health. Occupational medicine physicians can play critical roles in preventing the adverse health effects of manganese.

Lithium target performance evaluation for low-energy accelerator-based in vivo measurements using gamma spectroscopy

The operating conditions at McMaster KN Van de Graaf accelerator have been optimized to produce neutrons via the 7Li(p, n) 7Be reaction for in vivo neutron activation analysis. In a number of earlier studies (development of an accelerator based system for in vivo neutron activation analysis measurements of manganese in humans, Ph.D. Thesis, McMaster University, Hamilton, ON, Canada; Appl. Radiat. Isot. 53 (2000) 657; in vivo measurement of some trace elements in human Bone, Ph.D. Thesis. McMaster University, Hamilton, ON, Canada), a significant discrepancy between the experimental and the calculated neutron doses has been pointed out. The hypotheses formulated in the above references to explain the deviation of the experimental results from analytical calculations, have been tested experimentally. The performance of the lithium target for neutron production has been evaluated by measuring the 7Be activity produced as a result of (p, n) interaction with 7Li. In contradiction to the formulated hypotheses, lithium target performance was found to be mainly affected by inefficient target cooling and the presence of oxides layer on target surface. An appropriate choice of these parameters resulted in neutron yields same as predicated by analytical calculations.

Evaluation of indexes of in vivo manganese status and the optimal intravenous dose for adult patients undergoing home parenteral nutrition

There are no accurate indexes for determining the status of manganese in humans, and there is no clear recommended daily dose of this essential trace element to be administered in total parenteral nutrition solutions. The objectives were to evaluate accurate indexes of manganese status and elucidate the optimal manganese dose to be administered to adult patients undergoing home parenteral nutrition. Patients were administered total parenteral nutrition solutions providing 0, 1, 2, or 20 micromol Mn/d according to an on-off design, after which manganese concentrations in whole blood and plasma were determined. Magnetic resonance imaging (MRI) was performed to determine the intensity on T(1)-weighted images (MRI intensity) and T(1) values in the globus pallidus. Hematologic and biochemistry tests were also performed. High degrees of correlation were found between whole-blood manganese concentrations and both MRI intensity (r = 0.7728) and T(1) values (r = -0.7519) in the globus pallidus. A strong negative correlation was found between MRI intensity and T(1) values (r = -0.8407). The dose of 1 micromol Mn/d caused no change in MRI intensity or T(1) values, and the whole-blood manganese concentration remained within the normal range in all patients. Whole-blood manganese concentrations and MRI intensity and T(1) values in the globus pallidus are useful indexes of the status of manganese in humans. The optimal dose of manganese may be 1 micromol/d for adult patients undergoing home parenteral nutrition.

Manganese superoxide dismutase gene polymorphism and schizophrenia: relation to tardive dyskinesia.

There has been increasing evidence that deranged superoxide dismutase (SOD) activities might be a risk factor for schizophrenia and/or tardive dyskinesia (TD). In the present study, we investigated the genetic association between a functional polymorphism (Ala-9Val) in the human manganese (Mn) SOD gene and schizophrenia or TD (192 schizophrenics: 39 with TD and 153 without TD; 141 controls). No significant differences in the allelic or genotypic distribution between schizophrenics and controls were observed. However, we did find a significant difference in genotypic distribution between schizophrenics with and those without TD (p =. 03). Moreover, decreased -9Ala (mutant) allele was found among patients with TD (p =.02; odds ratio = 0.29; 95% confidence interval = 0.10-0.83). In conjunction with previous findings of increased free radicals and decreased SOD activities in TD subjects, these results suggest that the -9Ala (high activity) MnSOD allele may play a role in protecting against susceptibility to TD in schizophrenics.

Effect of human recombinant manganese superoxide dismutase and allopurinol on muscle contractility and blood flow following revascularization

Effect of human recombinant manganese superoxide dismutase and allopurinol on muscle contractility and blood flow following revascularization