Biliary Manganese Excretion in Conscious Rats Is Affected by Acute and Chronic Manganese Intake but Not by Dietary Fat

Malecki, Elise A.; Radzanowski, Gwendolyn M.; Radzanowski, Thaddeus J.; Gallaher, Daniel D.; Greger, J. L.

doi:10.1093/jn/126.2.489

Cited by 81 publications

(48 citation statements)

References 23 publications

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“…For example, the concentration of Mn in the diet is known to influence the amount of Mn absorbed from the gastrointestinal tract as well as its elimination via the bile. Adaptive changes to high dietary Mn intake include reduced gastroin- Mn content 3-10 lg/l 30-50 lg/l 200-300 lg/l testinal tract absorption, enhanced liver metabolism, and increased biliary and pancreatic excretion of this metal (Britton and Cotzias, 1966;Davis et al, 1993;Dorman et al, 2001Dorman et al, , 2002Finley and Davis, 1999;Malecki et al, 1996). Mn absorption from the diet is also influenced by the presence of other trace minerals, phytate, ascorbic acid, and other dietary constituents (Davidsson et al, 1991).…”

Section: The Absorption Distribution and Elimination Of Oral Manganesementioning

confidence: 99%

Nutritional aspects of manganese homeostasis

Aschner

2005

Molecular Aspects of Medicine

747

555

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Manganese (Mn) is an essential mineral. It is present in virtually all diets at low concentrations. The principal route of intake for Mn is via food consumption, but in occupational cohorts, inhalation exposure may also occur (this subject will not be dealt with in this review). Humans maintain stable tissue levels of Mn. This is achieved via tight homeostatic control of both absorption and excretion. Nevertheless, it is well established that exposure to high oral, parenteral or ambient air concentrations of Mn can result in elevations in tissue Mn levels. Excessive Mn accumulation in the central nervous system (CNS) is an established clinical entity, referred to as manganism. It resembles idiopathic Parkinson's disease (IPD) in its clinical features, resulting in adverse neurological effects both in laboratory animals and humans. This review focuses on an area that to date has received little consideration, namely the potential exposure of parenterally fed neonates to exceedingly high Mn concentrations in parenteral nutrition solutions, potentially increasing their risk for Mn-induced adverse health sequelae. The review will consider (1) the essentiality of Mn; (2) the concentration ranges, means and variation of Mn in various foods and infant formulas; (3) the absorption, distribution, and elimination of Mn after oral exposure and (4) the factors that raise a theoretical concern that neonates receiving total parenteral nutrition (TPN) are exposed to excessive dietary Mn.

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Section: The Absorption Distribution and Elimination Of Oral Manganesementioning

confidence: 99%

Nutritional aspects of manganese homeostasis

Aschner

2005

Molecular Aspects of Medicine

747

555

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“…These include the chemical form (79), the presence of other minerals and dietary constituents (33,80,81), and the age of the animal (82)(83)(84). Furthermore, adaptive changes to high dietary manganese intake lead to reduced absorption and enhanced hepatic (biliary) or pancreatic excretion of manganese (19,(85)(86)(87)(88).…”

Section: Routes Of Manganese Administrationmentioning

confidence: 99%

Manganese-Enhanced Magnetic Resonance Imaging

Boretius

Frahm

2011

Methods in Molecular Biology

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Manganese-enhanced magnetic resonance imaging (MEMRI) relies on contrasts that are due to the shortening of the T (1) relaxation time of tissue water protons that become exposed to paramagnetic manganese ions. In experimental animals, the technique combines the high spatial resolution achievable by MRI with the biological information gathered by tissue-specific or functionally induced accumulations of manganese. After in vivo administration, manganese ions may enter cells via voltage-gated calcium channels. In the nervous system, manganese ions are actively transported along the axon. Based on these properties, MEMRI is increasingly used to delineate neuroanatomical structures, assess differences in functional brain activity, and unravel neuronal connectivities in both healthy animals and models of neurological disorders. Because of the cellular toxicity of manganese, a major challenge for a successful MEMRI study is to achieve the lowest possible dose for a particular biological question. Moreover, the interpretation of MEMRI findings requires a profound knowledge of the behavior of manganese in complex organ systems under physiological and pathological conditions. Starting with an overview of manganese pharmacokinetics and mechanisms of toxicity, this chapter covers experimental methods and protocols for applications in neuroscience.

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“…The primary route of manganese excretion is via the biliary system, 35 with the kidneys only a secondary route. Hence, urinary manganese is also a poor index of chronic manganese exposure.…”

Section: Mixed Syndrome With Vestibular-auditory Symptomsmentioning

confidence: 99%

Neurologic manifestations in welders with pallidal MRI T1 hyperintensity

et al. 2005

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Abstract-Background: Neurologic symptoms have been attributed to manganese fumes generated during welding. Increased T1 MRI signal in the basal ganglia is a biologic marker of manganese accumulation. Recent studies have associated welding and parkinsonism, but generally without MRI corroboration. Objective: To characterize the clinical and neuropsychological features of patients with MRI basal ganglia T1 hyperintensity, who were ultimately diagnosed with neurotoxicity from welding fumes. Methods: The medical records of welders referred to the Department of Neurology with neurologic problems and basal ganglia T1 hyperintensity were reviewed. Results: All eight patients were male career welders with increased T1 basal ganglia signal on MRI of the brain. Several different clinical syndromes were recognized: a parkinsonian syndrome (three patients), a syndrome of multifocal myoclonus and limited cognitive impairment (two patients), a mixed syndrome with vestibular-auditory dysfunction (two patients), and minor subjective cognitive impairment, anxiety, and sleep apnea (one patient). Neuropsychometric testing suggested subcortical or frontal involvement. Inadequate ventilation or lack of personal respiratory protection during welding was a common theme. Conclusions: Welding without proper protection was associated with syndromes of parkinsonism, multifocal myoclonus, mild cognitive impairment, and vestibular-auditory dysfunction. The MRI T1 hyperintensity in the basal ganglia suggests that these may have been caused by manganese neurotoxicity. NEUROLOGY 2005;64:2033-2039 Welding utilizes an electric arc to melt and bond metals. Fumes with high concentrations of aerosolized metals generated by welding may cause systemic as well as neurologic problems.1-4 Although many elemental metals are released in welding plumes, the neurotoxicity is presumed to be primarily mediated by manganese. [5][6][7][8][9] Manganese neurotoxicity presents commonly as a parkinsonian syndrome 7,8,10,11 and has been reported to be associated with welding. 5,12 A biologic marker of manganese accumulation within the CNS is bilaterally increased T1 MRI signal within the basal ganglia, especially the globus pallidus, but also the striatum.1,13-18 Although T1 signal changes in these nuclei may be seen in several other conditions (e.g., nonketotic hyperglycemic episodes, hypoxia, neurofibromatosis, and other paramagnetic ions), it is an uncommon pattern. When the T1 hyperintensity is confined to the lentiform nuclei, and in the appropriate clinical setting, it has relative specificity for brain manganese. This MRI appearance suggests that the ambient fume intensity has been sufficient to affect the brain. Although an association between welding and parkinsonism has been postulated in two recent clinical series, the MRI scans in these patients were either normal or not reported. 5,12We report eight patients referred for neurologic evaluation and diagnosed with neurotoxicity from welding fumes. All had chronic and intense exposure to ambient welding fum...

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Biliary Manganese Excretion in Conscious Rats Is Affected by Acute and Chronic Manganese Intake but Not by Dietary Fat

Cited by 81 publications

References 23 publications

Nutritional aspects of manganese homeostasis

Nutritional aspects of manganese homeostasis

Manganese-Enhanced Magnetic Resonance Imaging

Neurologic manifestations in welders with pallidal MRI T1 hyperintensity

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