Prenatal diagnosis of glycogenosis type II was performed by direct assay of acid alpha-glucosidase (EC 3.2.1.20) in chorionic villous biopsy obtained by transcervical cannula aspiration from a pregnancy at risk in the 10th week of gestation. The exact value of the enzyme activity estimated by the use of antibody preparations for purified human liver acid alpha-glucosidase was in the heterozygous range, and so the homozygous enzyme deficiency could be excluded. The subsequent analysis of cells cultured from amniocentesis sampling in the 18th week of gestation resulted in a similar outcome. The study with antibodies showed that in 23 control chorionic villi obtained during gestational ages between 7-13 weeks, 1-15% of the total alpha-glucosidase activity at pH 4.0 were due to renal or neutral enzyme. This indicates that it may be important to employ antibodies for prenatal diagnosis using chorionic villous sampling. A healthy and unaffected boy was born. The biochemical values obtained from an umbilical blood specimen were in accordance with the results of the prenatal diagnosis.

Adult↗

PubMed1986

New approaches for the detection of early activation products in thrombotic states.

The occurrence of a consumption coagulopathy as well as prethrombotic and thrombotic states are connected with the formation of thrombin. The proteinase acts upon physiological substrates leading to activation products, e.g. fibrinopeptides, platelet factors or thrombin-antithrombin III-complex. For the determination of such products we have developed immunochemical assays, which detect parameters of a direct or indirect action of thrombin in a specific and sensitive manner: 1. ELISA for determination of platelet factor 4; 2. Latex-test for determination of D-Dimer; 3. ELISA for determination of thrombin-antithrombin III complex. Preliminary results from clinical investigations indicate that the determination of these parameters can be valuable for the diagnosis of activation processes of the clotting system.

Blood Coagulation Disorders↗

PubMed1986

Determination of protein C in plasma.

Three new methods to characterize the function of protein C in plasma are described and compared to established procedures. Two methods make use of a snake venom derived specific protein C activator which allows rapid, sensitive and standardizable assays in plasma without sample pretreatment. The other technique is a two dimensional immunoelectrophoresis in the presence of calcium or EDTA, respectively.

Antithrombins↗

PubMed1985

Development of a photometric assay for activated partial thromboplastin time and its application to the Cobas Bio centrifugal analyzer.

We describe a two-step procedure for APTT that can be performed on photometric devices. It includes preincubation of diluted plasma with ellagic acid and phospholipids and a starting reagent that contains calcium and a chromogenic peptide substrate for thrombin, Tos-Gly-Pro-Arg-pNA. Reaction time is recorded from addition of the starting reagent until thrombin formation occurs, and a prefixed amount of substrate is cleaved. The pattern of sensitivity to clotting factors and heparin was similar to clotting assays and the substrate used did not interfere with the activity of factor Xa. An application of the method was made for the Cobas(R) Bio centrifugal analyzer. Absorbance readings were sent to an external computer and were transformed into reaction times by a computer program. Although the results are independent on fibrinogen concentrations, from kinetic data of the reaction curve fibrinogen concentrations can be estimated. Correlation studies showed good correspondence to clotting methods (r = 0.92, n = 53) as well as an excellent precision (CV 3% for inter-assays, n = 15) and high throughput of samples (greater than 100/h) in the automated assay.

Apoproteins↗

PubMed1985