Anticoagulant activities and effects on platelets of a heparin fragment with high affinity for antithrombin

A fragment of heparin containing 10–16 sugar units and retaining ability to bind to antithrombin III has been prepared by degrading standard heparin with nitrous acid. This fragment greatly potentiated the inhibition of factor X_a by antithrombin III but had virtually no effect on the inhibition of thrombin. Studies on heparin neutralization showed that the fragment was affected to a much lesser extent than standard heparin by heparin neutralizing components in plasma. The heparin-potentiated aggregation of platelets by low concentrations of ADP was measured for a number of heparin fractions and the fragment. The molecular weight of the heparin was found to be the most important factor determining the platelet aggregation activity, low molecular weight fractions including the fragment being much less active than high molecular weight ones.     

Human lymphoblastoid cell lines derived from individuals without lymphoproliferative disease contain the same latent forms of Epstein-Barr virus DNA as those found in tumor cells.

The physical state of the intracellular Epstein-Barr virus DNA was characterized in four human lymphoblastoid cell lines, F-265, NC-37, U-303 L, and PG-1, derived from individuals without lymphoproliferative disease. For comparison, a previously investigated Burkitt lymphoma line, Raji, and a more recently established cell line of that origin, Rael, were also studied. The techniques employed were CsCl density gradient centrifugation, glycerol gradient centrifugation, and ethidium bromide-CsCl density gradient centrifugation in combination with nucleic acid hybridization, as well as electron microscopy contour length measurements of purified circular EBV DNA. All six cell lines contained multiple copies of covalently closed circular EBV DNA-molecules of the same size, as well as viral DNA with the properties of integrated DNA. No differences could be detected between the forms of EBV DNA present in cell lines derived from non-malignant sources and those present in lymphoma lines.     

Beeinflussung der Vorphase der Gerinnung durch Dextran 150

Zusammenfassung 1. Die Injektion von 10 ml Dextran 150 führt beim Kaninchen zu einer gesteigerten Agglutinationsbereitschaft der Thrombocyten.2. Die Infusion von weiteren 40–60 ml Dextran 150 führt nicht zu einer zusätzlichen Steigerung der Agglutinationsbereitschaft.3. Nach Infusion von 50–70 ml Dextran 150 wird ein Inhibitor der Vorphase der Gerinnung nachweisbar. Die Aktivität dieses Inhibitors wird durch Adsorption des Plasmas mit Aluminiumhydroxyd oder Bariumsulfat nicht beeinträchtigt. Die Aktivität des Inhibitors ist auch im kontaktaktivierten System (Glaswolle) nachweisbar.4. Die Plasmathrombingerinnungszeit wird im Versuchsablauf nicht beeinflußt.5. Die Antithrombin III-Aktivität fällt nach Infusion von Dextran 150 ab.6. Die maximale Amplitude des Thrombelastogramms ist nach Infusion von Dextran 150 verschmälert. Auch im Mischthrombelastogramm, nach Zusatz von Normalblut, ist eine Verschmälerung der maximalen Amplitude nachweisbar. Beziehungen zwischen dem dargestellten Inhibitor und Fibrinogenabbauprodukten werden diskutiert.Nach der wahrscheinlichkeitsstatistischen Prüfung läßt sich erwarten, daß die Versuchsergebnisse reproduzierbar sind. Die statistische Prüfung der Daten zeigte darüber hinaus, daß der Prozeß der Plättchenagglutination im Plättchenagglutinationstest und der Prozeß der Antithrombin III-Bildung im Antithrombin III-Test in einer multiplikativen Progression fortschreiten.

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Summary 1. Injection of 10 ml Dextran 150 in rabbits induces an increased tendency of platelets to agglutination.2. The infusion of additional 40–60 ml Dextran 150 induces no further increase.3. An inhibitor of the prephase of clotting mechanism is found after the infusion of 50–70 ml Dextran 150. The activity of this inhibitor is not impaired by adsorption of plasma to aluminiumhydroxyde or bariumsulfate. The inhibitor activity shows equally up in a contact activated system.4. The plasma thrombin clotting time is not influenced by infusion of Dextran 150.5. Antithrombin III-activity decreases after infusion of Dextran 150.6. The maximum width of the thrombelastogram is reduced after infusion of dextran 150. Also a mixture of normal blood with blood after infusion of dextran 150 shows a reduction of the maximum width.Connections between the demonstrated inhibitor and fibrinogen degradation products are discussed.It might be expected according to the statistical calculation of probabilities, that these data can be reproduced.Furthermore the statistical calculation of the data showed, that the process of platelet agglutination in the used method and the formation of antithrombin III activity in the used method procede in a multiplicative progression.

     

Computed tomography of intraorbital foreign bodies

Computed tomography (CT) has been shown to be an important diagnostic tool in the evaluation of intraorbital foreign bodies (IOFB). In order to further analyze the capacity and limitations of CT in this respect, 55 cases with IOFB (intraocular and extraocular) detected at CT were retrospectively analyzed. It was shown that CT was an excellent diagnostic modality in detecting and localizing IOFB of different material and superior to ultrasonography in this respect. Still, even with high resolution CT, there are some limitations of this modality that are discussed. CT is recommended as the primary diagnostic tool in the detection and localization of intraocular and extraocular foreign bodies.