[Cereal related complaints in children]. / Granengerelateerde klachten bij kinderen.

There's a lot of attention for gluten-free diets on social media. Doctors get many questions about gluten sensitivity or possible wheat allergy. With some basic knowledge, it's easier to give answers to these questions and to prevent unnecessary and sometimes harmful diets. This article gives basic information about cereals, gluten, grasses and their crossreactivity. We give an overview about the differences between celiac disease, gluten sensitivity and IgE-mediated wheat allergy. We also describe diagnostics, treatment and natural history of coeliakie, gluten sensitivity and wheat or cereal allergy.

Determination of methacrylic acid in the drain of a biotrickling filter using isotachophoresis and capillary zone electrophoresis.

The performance of a biotrickling filter for treatment of concentrated waste gases was investigated. The macrokinetics of methylmethacrylate degradation in the biotrickling filter is studied by measuring the degradation product methacrylic acid in the drain of the filter. The drain was analysed using isotachophoresis (ITP) and capillary zone electrophoresis (CZE). The CZE analyses were carried out in an I.D. 75 microm capillary at 20 kV (negative inlet polarity) using a 0.01 M Tris-acetate buffer of pH 4.45. The electroosmotic flow (EOF) was suppressed by addition of CTA and PVA to the buffer. Detection was at 214 nm. After filtration through a 0.45-microm filter, samples were directly injected. The calibration graph was linear between 10 and 800 mg/l methacrylic acid, with an analysis time under 2 min.

Ultraviolet-absorbing organic anions in uremic serum separated by capillary zone electrophoresis, and quantification of hippuric acid.

Organic anions accumulated in blood serum of patients with chronic renal failure were separated by a novel technique: closed-system capillary zone electrophoresis (CZE) in a pH6 carrier-electrolyte system. Hippuric acid (HA), p-hydroxyhippuric acid, and uric acid were identified by their co-elution with standards prepared in ultrafiltered normal serum and by comparison with the corresponding ultraviolet-detected peaks positively identified in the HPLC analyses. Analysis time for the entire profile is 8 min. Repeatabilities (CVs) of CZE migration times and peak areas of the three acids in serum samples were about 0.7% and 6%, respectively. We quantified HA in 10 ultrafiltered uremic serum samples and compared results with those by a previously described HPLC procedure. The very good agreement further supports the identification of hippuric acid. Accuracy and precision of the CZE method were similar to those for the HPLC gradient-elution method, but analysis time for HA (8 min) is much less than by HPLC (90 min). Our technique is very suitable for selective, rapid analysis for (ultraviolet-absorbing) anionic constituents in ultrafiltered uremic serum, without any sample pretreatment.

Isotachophoresis of allergenic extracts.

One aspect of the isotachophoretic determination of protein patterns in biological samples of interest is the characterization of allergens. This group of (glyco) proteins, causing allergic reactions, is used both for diagnosis and in the treatment of allergy. The aim of this investigation was to obtain a maximum amount of information, within one run, on the (glyco)protein composition of a number of allergenic extracts (e.g., from pollen or house dust mites). Commercially available extracts were dialysed prior to analysis to remove disturbing buffer constituents. A high-pH system was chosen in order to obtain a maximum amount of information from the samples (1-2 microliter). The leading electrolyte was 0.01 M C1-, buffered with Tris (pH 8.2), containing 0.2% w/v hydroxyethylcellulose, and the terminating electrolyte was beta-alanine, buffered to pH 10 with Ba(OH)2. The total analysis time was 15-20 min using a PTFE capillary (0.2 mm I.D.). The pre-separation current was 30 microA and the current during detection was 15 microA. UV absorption was measured at 280 nm. For optimal discrimination of the compounds of interest, an ampholyte mixture was used for spacing. The analytical procedure yielded highly reproducible UV patterns. Significant differences between various allergenic extracts were observed. It was concluded that isotachophoresis is a powerful method for the physico-chemical characterization of individual allergenic extracts, e.g., with respect to manufacturing and quality control.

Determination of quinine in beverages, pharmaceutical preparations and urine by isotachophoresis.

The suitability of isotachophoresis for the determination of quinine in different samples was investigated. The operational conditions were 0.01 M potassium-morpholinoethanesulphonic acid (MES) (pH 6.0) with 0.05% Mowiol as the leading electrolyte and ca. 0.005 M creatinine-MES as the terminating electrolyte. The analyses were carried out at 25 microA in a 0.2 mm I.D. PTFE capillary with UV and conductivity detection. Quinine-containing beverages were degassed by sonification and directly injected. The limit of detection was 5 mg/l with a 4 microliter injection volume. The allowed concentrations could be determined with sufficient accuracy. Analgesic preparations were dissolved in a solution of 5 X 10(-3) M MES with sonification. The quinine levels found agreed well with the declared values. The other constituents of the pharmaceuticals did not interfere with the analysis. Urine samples from volunteers were analysed after consumption of tonic. The samples were extracted with dichloromethane-isopropanol (95:5), vortexed, centrifuged, evaporated to dryness, the residue dissolved in 5 X 10(-3) M MES and analysed. At a concentration factor of 33, the limit of detection was ca. 60 micrograms in 48-h urine: 2-15% of the quinine consumed was excreted as the parent compound in the first 48 h after consumption. The combination of the extraction procedure and the operational system makes the method suitable for the determination of a number of other alkaloids in physiological samples.

Determination of heavy metals by isotachophoresis.

The suitability of isotachophoresis for the analysis of metals in, e.g., environmental samples was studied. In a cationic operational system the heavy metals Fe, Cu, Ni, Cd, Co, Zn, Pb and Mn were simultaneously determined. The separation was achieved through complex formation with one of the counter ions, hydroxyisobutyric acid. The other counter ion was acetic acid, the leading ion was 0.02 M potassium or sodium (pH 4.1) and the terminator was H+. The analysis time was 15 min at 60 microA in a 0.2 mm I.D. capillary. Aqueous samples containing ppm and ppb amounts were enriched on a cation exchanger with an extremely low affinity for sodium (Chelex 100). Good recovery, linearity, precision and accuracy were obtained even down to the ppb range. Although the sensitivity of the method is not greater than that of some of the more established methods for the individual metals, a great advantage of isotachophoresis is the simultaneous determination of the metals, with equal response factors. An example is given of the determination of metals, including aluminium, in serum.