Trace metals used therapeutically

Although the mechanism for the neurotoxicity of Al is not well understood, recent work by Gardiner [90] has shown that 10—30% of the plasma Al is ultrafiltrable. These low-molecular weight species could be more easily transported across membranes and thus reach the brain more easily than could protein bound Al. The higher levels of Al in the cerebrospinal fluid of patients on dialysis [90] would support this view. 

The sensitivity of ETA—AAS for Al is approximately 2.5 x 10-n g for 1% absorption at 309.3 nm. This amount of Al is equivalent to 2.5 pi serum or urine at 0.4 pmol l 1 (10pgl-1). Langmyhr and Tsalev [91] used only 2 pi of serum of haemolysed whole-blood for analysis and found that a direct analysis using a two-stage ashing procedure first at 500°C and then 1200°C 

REFERENCE AND THERAPEUTIC LEVELS OF TRACE METALS IN BODY FLUIDS AND TISSUES 

Metal Matrix Concentrations in tissues/fluids /imol l 1 Reference Therapeutic levels levels ETA-AAS sensitivity (Pg/0.0044 A) Volume required for analysisb (pl/0.0044 A) 

All of these procedures used either standard additions or matrix matching of the standards for calibration, with linear working ranges up to 3.7 fimol l-1 (100/igl-1). The within batch precision of 0.053 (RSD), day-to-day precision of 0.059 (RSD) and recoveries of added A1 of 98.5 6.5% reported by Fuchs et al. [93] are representative of the quality of analysis achieved with the other procedures that have been discussed. 

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The editors concept of clinical chemistry, as stated in previous volumes of this serial publication, encompasses a wide field of subjects— from the mechanism of blood coagulation to the microbiological assay of vitamins, and from the significance of trace metals in health and disease to the therapeutic application of increased gas pressure. The natural history of clinical conditions and their comparison with normal controls share one common feature, namely, the central position of some species of molecules, be they small or large, all of them the natural subject of chemical research. Hence, practical methods develop, either manual or mechanized, the results of which become increasingly more useful for the clinician in diagnosis, therapy, and prognosis. 

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