Increased interest in the analysis of aminothiols in body fluids during the last years results in a request for high-throughput analytical methods for their determination. We report here a novel, high-throughput method for the determination of total concentrations of biogenous aminothiols - homocysteine, cysteine, glutathione, cysteinylglycine, gamma-glutamylcysteine, and of penicilamine, mercaptopropionylglycine, and cysteamine, three compounds used to treat disorders of aminothiol metabolism in plasma and urine. Samples were reduced with tris(carboxyethyl)phosphine and labeled with 5-(bromomethyl)fluorescein. Capillary electrophoretic separations were performed in 60 mmol/L borate - 15 mmol/L sodium dodecyl sulfate - 2-amino-2-methyl-1-propanol, pH 10.0, with laser-induced fluorescence detection. Analysis time was less than 2 min. The assay is linear (r > 0.999) up to 500 micromol/L. Reproducibilities of migration times (coefficient of variation, CV) were < 0.5%. Interassay repeatabilities (CV, n = 10) were 5.08% and 6.09% for 5 micromol/L addition of homocysteine and 0.60% and 3.78% for 100 micromol/L addition of cysteine in plasma and urine, respectively. Recovery values were within 94-106% and sensitivity was better than 0.19 micromol/L for all analyzed compounds. Results agreed well with a standard high-performance liquid chromatography (HPLC) method. The diagnostic usefulness of the method has been proven on 79 samples of cystinuric patients and 12 samples of homocystinuric patients. We report here a novel method for the determination of aminothiols in body fluids by capillary electrophoresis (CE). Determination is fast and sensitive enough for diagnostic purposes.

To analyze the diagnostic value of various laboratory tests for the confirmation of adult-onset glycogen storage disease type II (GSD II), we performed a clinical, biochemical, and genetic study of 18 patients with this disease. Measurement of acid alpha-glucosidase (GAA) activity in muscle and histopathologic analysis of muscle tissue appeared to have no additional value when GAA activity in leukocytes was clearly deficient. Our study showed that creatine kinase elevation is a sensitive marker of GSD II. A diagnostic protocol is formulated.

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Monoclonal gammopathy of undetermined significance (MGUS) is an asymptomatic, potentially malignant condition. It has been established that annually approximately 1-2% of MGUS cases transforms into one of the malignant forms of monoclonal gammopathies. Progression risk factors include the quantity and type of M-protein, and namely the ratio of free light immunoglobulin chains (FLC). These factors, enable purposeful stratification of MGUS individuals. Some authors consider suppression of polyclonal immunoglobulin levels to be another progression factor. The aim of the study was to compare polyclonal immunoglobulin (PIg) levels with uninvolved heavy/light chain pair (HLC) levels in order to verify the degree of immunoparesis depending on MGUS risk category (0-3). The analyzed set consisted of 159 serum samples from MGUS patients (102 IgG, 57 IgA), who were stratified into 4 risk groups (0 - low, 1 - low-intermediate, 2 - high-intermediate and 3 - high risk of transformation). The results of analysis showed that with increasing degree of MGUS increases risk of immune paresis defined by decreasing levels of polyclonal immunoglobulins, ie. IgA and IgM in the case of IgG MGUS, respectively, IgG and IgM in case of IgA MGUS. Significant differences were also found when analyzing the levels of uninvolved HLC pairs IgG kappa (resp. IgG lambda) in IgG lambda (IgG kappa) dominant secretion. In the case of MGUS with IgA isotype, the results were similar. Discovery of the connection between the degree of immunosuppression and the level of MGUS risk contributes to our understanding of the relationship between biology, development and potential malignant transformation of MGUS. It is apparent that uninvolved HLC pair assay enables more reliable identification of at-risk MGUS patients than a simple quantitative assay for polyclonal immunoglobulins alone.