Manganese whole blood concentrations

Dietary supplementation with 40 mg of manganese increased both fecal excretion and whole blood concentration of the mineral but had no effect on serum lipids or fecal fat. 

In all work on the determination of whole blood concentrations of manganese, stainless steel needles seem to have been used. Since the concentration of manganese in whole blood is at least 10 times greater than in serum, the effect of contamination will be proportionally smaller. Nevertheless if reliable values for manganese in whole blood are to be achieved, the use of special sampling techniques would seem to be necessary. 

The first report of abnormal manganese concentrations in human epileptics was published in 1967 and indicated high serum manganese concentrations in epileptics compared to non-epileptic controls (4). The authors were apparently unaware of the previous animal work that demonstrated a link between manganese deficiency and increased susceptibility to seizure. It was not until 1978 that Tanaka ( 5) presented data indicating that whole blood manganese concentrations were lower in epileptic children than in control children of similar age. A year later Papavasiliou and coworkers (6) in a study of 52... 

In 1980 Hoffman (7) reported that serum manganese concentrations were the same in epileptics and non-epileptic controls in populations of both adults and children. This observation suggests that the differences reported by Tanaka (5) and by Papavasiliou, et al. (6) in whole blood were due to differences in manganese concentrations in the blood cells, probably erythrocytes. Whether this apparent deficiency in the erythrocytes of some epileptics translates into lower manganese concentrations in other tissues of these epileptics is unknown. 

Table I. Correlation Between Whole Blood Manganese Concentration and Plasma Anticonvulsant Concentrations in Epileptic Patients...

Figure 1. Whole blood manganese levels in epileptic patients vs. medication index. Whole blood manganese was measured by atomic absorption spectrophotometry. The medication index is a composite measure of anticonvulsant concentrations in plasma as a relationship of each anticonvulsant to its therapeutic range. The medication index increases as a function of the relative concentration of each anticonvulsant and as a sum of all anticonvulsant concentrations. There was no correlation between whole blood manganese and medication index (r = -0.236.)...

Whole blood levels of manganese reflected differences in levels of dietary manganese. As shown in Figure 6, whole blood manganese concentrations of rats fed both low fat and high fat diets tended to increase as level of dietary manganese increased. 

The first requirement can be easily fulfilled by the preconcentration of the analyte before the analysis. Preconcentration has been applied to sample preparation for flame atomic absorption (25) and, more recently, for ICP (79,80) spectroscopy. However, preconcentration is not completely satisfactory, because of the increased analysis time (which may be critical in clinical analysis) and the increased chance of contamination or sample loss. Most important, however, a larger initial sample size is necessary. The apparent solution is a more sensitive technique. Table 2 lists concentrations of various metals in whole blood or serum (81,82) in comparison to limits of detection for the various atomic spectroscopy techniques. In many cases, especially for the toxic heavy metals, only flameless atomic absorption using a graphite furnace can provide the necessary sensitivity and accommodate a sample of only a few microliters (Table 1). The determination of therapeutic gold in urine and serum (83,84), chromium in serum (85), skin (86) and liver (87), copper in semen (88), arsenic in urine (89), manganese in animal tissues (90), and lead in blood (91) are but a few examples in analyses which have utilized the flameless atomic absorption technique. 

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