Fabry Disease (FD) is an X-linked multisystemic lysosomal disorder caused by mutations of α-galactosidase (GLA) gene. Only a few of the 450 genetic lesions identified so far have been characterised by in vitro expression studies. Thus the significance of newly identified GLA nucleotide variants sin FD patients which lead to α-galactosidase (GAL-A) amino acid substitutions or intronic changes can be uncertain. We identified three GLA mutations: c155G>A (p.C52Y), c548G>C (p.G183A), c647A>G (p.Y216C) in as many individuals (two male; one female), and performed in vitro expression studies and Western Blot analysis, in order to clarify their functional effects. Reduced GAL-A activity and normal or partially reduced mutant proteins were present in all overexpressed mutant systems in which, three-dimensional structural analysis showed that the active site was not directly involved. We hypothesize that the three new mutations affect the GAL-A protein, leading to conformational FD. When, mutant proteins overexpressed in COS-1 cells and in patients’ lymphocytes were tested in the presence of the 1-deoxygalactonojirimicin (DGJ) chaperone, the p.G183A and p.Y216C systems showed increased GAL-A enzyme activities and protein stabilisation, while p.C52Y was not responsive. We underline that genetic, biochemical and functional studies are helpful in clarifying the consequences of the missense genetic lesions detected in FD. ERT is the elective therapy for Fabry patients but it is not always possible to issue the enzyme’s active form in all involved organs. Our study endorses the hypothesis that an active-site-specific chemical chaperone, which could be administered orally, might be effective in treating GAL-A conformational defects.

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The method previously described by Casetta eta/. for the determination of aluminium in dilute (1 + 1) human serum using matrix modification and a stabilised temperature platform furnace has been considered. The combination of the platform, integrated absorbance, new coated tubes and oxygen addition to the charring step, provided better precision and smaller variation during the life of the tube. Good results were achieved by standardising the procedure against a calibration graph if integrated absorbance signals were used for quantitation. The calibration was linear up to at least 150 pg I-' of aluminium; the within-run and between-run precision was 5.5 and 6.5%, respectively (at 14.3 pg 1-1 of aluminium); and the recovery of aluminium added to pooled serum ranged between 97 and 102%. Furnace lifetimes in excess of 200-250 firings using oxygen ash i ng were routinely achieved.

Recently the possible storage of dextran-related material in patients undergoing regular haemodialysis has been suggested. We examined biopsy and autopsy specimens of 32 patients treated with regular haemodialysis for 61 +/- 34 months. All patients received dextran-40 as a plasma expander because of hypotension during haemodialysis. The same study was carried out in a control group of 11 haemodialysed patients who were given other plasma expanders. In the 11 patients who received larger doses of dextran-40 (0.38 g/kg body weight per week) we found particles in the cytoplasm of macrophages in various organs, which proved PAS positive and diastase resistant on light microscopy, and birefringent on polarisation. Electron microscopy revealed a fibrillar structure, but ionic analysis by electronic sampler on scanning electron microscopy excluded the presence of silicon. No intracellular inclusions were observed in the control group, nor in the patients given dextran-40 in doses lower than 0.08 g/kg body weight per week. As we also found a linear relationship between the number of particles and the dextran-40 doses given, we hypothesise that the material demonstrated in the macrophages is a structurally modified dextran.

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