Einleitung: Bei Patienten mit einem akuten Schlaganfall kann speziell bei hypotonen Blutdruckwerten der Einsatz kolloidaler Lösungen in Erwägung gezogen werden. Die Eignung von Gelatinelösungen wurde bislang noch nicht untersucht, obwohl sie als kolloidales Volumenersatzmittel breite Verwendung finden.

Letters to the Editor: Haemophilia A in a female caused by coincidence of a Swyer syndrome and a missense mutation in factor VIII gene -

An abnormal fibrinogen was identified in a man with suspicious prolonged prothrombin time and a mild bleeding tendency. Coagulation studies showed marked prolonged thrombin and reptilase clotting times and a discrepancy between functional fibrinogen test and fibrinogen antigen. The rate of fibrinopeptide B release by thrombin was slightly delayed while the release of fibrinopeptide A was only half the normal amount. DNA sequencing revealed a heterozygous C to T point mutation in position 1202 of exon 2 of the Aα chain, resulting in the substitution of Arg → Cys at position 16, the thrombin cleavage site. This mutation was found also in his 2 children. Both had a mild bleeding tendency too.

ZusammenfassungBei einem 35jährigen Patienten mit Sarkoidose im Stadium I trat nach einer Analfistelresektion ein kontinuierlicher Abfall der Thrombozyten bis 4 T/μl mit entsprechender klinischer Manifestation der dadurch bedingten hämorrhagischen Diathese auf. Nach Ausschluß einer heparinassoziierten Thrombozytopenie (HAT) und einer malignen hämatologischen Systemerkrankung wurde unter der Ausschlußdiagnose Autoimmunthrombozytopenie eine Hochdosis-Immuntherapie mit einem hochkonzentrierten Immunglobulinpräparat durchgeführt. Dies führte zu einem raschen Anstieg der Thrombozytenzahl, welcher auch nach Beendigung der Immunglobulingabe anhielt. Aufgrund des klinischen Verlaufes konnte die Diagnose einer Autoimmunthrombozytopenie bestätigt werden. Die vorangegangene Inhalationsnarkose muß als mögliches Triggerereignis angesehen werden.

Background. No data exist regarding the inter-laboratory reproducibility of the heparin-induced-platelet-activation (HIPA) test, the most widely used functional assay in Germany for the detection of heparin-induced thrombocytopenia (HIT) antibodies. Methods. Nine laboratories used an identical protocol to test eight different sera with the HIPA test. Five laboratories also tested the sera with a platelet factor 4 (PF4)/heparin-complex ELISA. Cross-reactivity with danaparoid-sodium was assessed using 0.2 aFXa units instead of heparin in the HIPA test. Results. Two of nine laboratories had no discrepant HIPA test results. Four laboratories differed in one sample, one reported two discrepant results, and two laboratories reported more than two discrepant results. Cross-reactivity with danaparoid-sodium test results differed among laboratories. PF4/heparin ELISA results were identical in all five laboratories. Conclusion. The HIPA test requires strict quality control measures. Using both a sensitive functional assay (HIPA test) and a PF4/heparin; ELISA will allow detection of antibodies directed to antigens other than PF4/heparin complexes as well as detection of IgM and IgA antibodies with PF4/heparin specificity.

1III. Department of Medicine, Westpfalz-Klinikum, Kaiserslautern 2Department Medical Engineering, FH Jena, Germany

SummaryElectrospray ionisation mass spectrometry was used to probe the structure of the new N-linked oligosaccharide in fibrinogen Kaiserslautern (γ 380 Lys→Asn). The mass increase of 2177 Da in the new γ chain indicated the attachment of a fully sialylated biantennary oligosaccharide on the new Asn residue; the expected increase for this change being 2192 Da. Some 95% of the new oligosaccharide was in the disialylated state while only 5% of the endogenous γ chain carbohydrate was disialylated in the control. Mass measurements of intact Kaiserslautern γ chains after neuraminidase treatment of the native fibrinogen confirmed a total of three residues of sialic acid in the dominant isoform. Incubation with endoglycosidase F showed that the new oligosaccharide was more resistant to hydrolysis than the endogenous one. Recent X-ray analyses of covalently linked D domains show that position γ 380 is distant from both the GPR binding pocket and the D-D interface. It appears that the polymerisation defect of this fibrinogen results from electrostatic repulsion between condensing protofibrils and that this is induced by the two new residues of sialic acid that are present on the new γ chain.

An adult woman diagnosed with cerebral thrombosis following a caesarean section was found to have severely prolonged thrombin and reptilase times. Five other family members also had prolonged, but variable, thrombin and reptilase times. Analysis of purified fibrinogen on reducing SDS‐PAGE revealed an additional band, in all family members, which migrated immediately below the normal Bβ band. Western blotting indicated that this band was a gamma chain and endoglycosidase‐F digestion established that it contained an additional oligosaccharide side chain. Partial acid hydrolysis localized the new oligosaccharide to the C‐terminus of the gamma chain. Amplification of this region by PCR and subsequent DNA sequencing demonstrated a single base substitution altering the normal 380 Lys (AAG) codon to Asn (AAT), producing a new Asn‐Lys‐Thr glycosylation site. The propositus and one other family member were homozygous for this mutation but the remaining four family members were heterozygous. The polymerization of purified fibrin monomers from the propositus was grossly abnormal; however, the polymerization curve was almost normalized by the removal of terminal sialic acid residues. This suggests that the polymerization defect was primarily caused by additional negatively charged sialic acid residues present on the new oligosaccharide. Further analysis of the D domain of purified fibrinogen established that calcium binding to the high affinity site remained unaffected by the bulky carbohydrate side chain or negatively charged sialic acid residues.