[A rapid method of HbA1c determination in a pediatric diabetic patient sample]. / Schnellbestimmungsmethode von HbA1c in einem pädiatrisch diabetologischen Patientengut.

A new Method for HbA1c measurements (Abbott vision) was evaluated. 107 patients (45 F, 62 M) of a paediatric diabetes clinic participated. The mean age was 14.9 (5.8-26.3) years, the mean duration of diabetes was 7.6 (0.1-21.1) years. Measurements were performed immediately after capillary blood sampling, the result was available within 15 min. The automated HPLC-system Diamat was used as a reference method, blood samples were stored at 4 degrees C and analysed within 24 h after blood sampling. There was a close correlation between both methods (r = 0.96, P < 0.0001). In the lower range the results measured by Abbott Vision were slightly lower, whereas in the higher range the results were slightly higher (HbA1c (Abbott) = 1.53 + HbA1c (Diamat).0.84). The accuracy seems to be satisfactory for estimating metabolic control. The HbA1c-result is available within 15 min which means a major advantage for the management of children and adolescents with type I diabetes.

[Determination of the serum protein concentration based on the measurement of density by the mechanical oscillator technique (author's transl)]. / Gesamteiweissbestimmung im Serum durch Dichtemessung nach der Biegeschwingermethode.

A linear relation is well established between the density and protein concentration of the serum. The measurement of protein concentration by a new technique for the determination of the absolute density, the mechanical oscillator technique, was investigated. The method is based on the determination of the resonant frequency of a mechanical bending-type, U-shaped glass tube oscillator filled with the sample. The shift in the resonant frequency of the oscillator caused by the mass of the defined volume of the sample taking part in the vibration can be used to calculate the density or protein concentration of the sample. In spite of the low specificity of the method, the interference of substances like glucose, urea or triglycerides is small. Simplicity and rapid results of high accuracy recommend the mechanical oscillator technique for the routine laboratory.

[Low molecule and middle molecule metabolites with haemodynamic activity in the ultrafiltrate from uraemic patients (author's transl)].

Substances causing blood pressure changes and myocardial damage in rats were first detected in the ultrafiltrate obtained from patients on long-term haemodialysis by means of size separation, high-voltage electrophoresis and thin-layer chromatography. Of the 100 to 140 fractions produced by Sephadex G 15 chromatography at least 3 raised the blood pressure when administered in doses of 2 to 10 mg/0.1 to 0.2 ml 0.9% NaCl, that is the high molecular fraction 18 to 23 and the low molecular fractions 71 to 72 and 73 to 74. The fractions 96 to 98 and 97 to 106 showed high toxicity. Less than 1 mg/0.1 to 0.2 ccm 0.9% NaCl produced cardiac arrest. The fractions 35 to 55, which originate from the middle molecules and are retained in regularly uraemia, contain substances which caused a reduction in blood pressure at low dosage and cardiotoxic effects at a dosage of more than 10 mg. Thin-layer chromatography indicates that the substances most probably consist of peptides whose structure contains the amino acids leucine, isoleucine, valine, glutamic acid, aspartic acid, alanine and cystine.