[Properties and virus safety of a pasteurized antithrombin III concentrate]. / Eigenschaften und Virussicherheit eines pasteurisierten Antithrombin III-Konzentrates.

In the last decade it appeared more than once that blood donations were contaminated by hitherto unknown viruses. Due to this fact, further steps have to be included into the manufacturing procedure of even up to now safe products from human plasma to eliminate potential new risks. A procedure is described which enables the pasteurization of antithrombin III analogous to albumin without major changes in the properties of the molecule. Thus the new product Kybernin HS/P was obtained. The efficacy of the pasteurization step was tested using relevant human pathogenic viruses. The following titers of important viruses could be totally inactivated within the pasteurization time (h) given in brackets HIV: (human immunodeficiency virus) greater than or equal to 10(6.7) (1), CMV (cytomegaly virus) greater than or equal to 10(4.5) (1), HSV (Herpes simplex virus) greater than or equal to 10(6.8) (4), Polio (poliomyelitis virus) greater than or equal to 10(6.9) (4).

[Determination of thromboplastin time with a new standardized thromboplastin from human placenta: results of a cooperative study]. / Bestimmung der Thromboplastinzeit mit einem neuen standardisierten Thromboplastin aus menschlicher Plazenta: Ergebnisse einer kooperativen Studie.

In five centres a new sensitive standardized thromboplastin from human placenta (Thromborel S) for determination of prothrombin time (PT) was evaluated on plasmas from healthy subjects, from patients on oral anticoagulant therapy and from patients with different diseases, especially of the liver. The standardization of the human placenta thromboplastin (HPT) for prothrombin time determination was performed by comparison with a lot of the Reference Preparation British Comparative Thromboplastin (BCT). The obtained International Sensitivity Index (ISI) for 14 differents lots of the new thromboplastin varied between 1.04 and 1.29 (mean value: 1.16). The reagent is highly sensitive to the factors of the extrinsic coagulation pathway and is not affected by heparin at least up to 0.6 IU/ml. From the comparison with the British Comparative Thromboplastin lot No. 235, a therapeutical range for the stable phase of the oral anticoagulation of 2.4-4.0 prothrombin ratio or 15-27% of normal, respectively, was obtained. Comparison of prothrombin time determination using the Human Placental Thromboplastin and the British Comparative Thromboplastin lot No. 235 in 330 patients on oral anticoagulation showed good correlations either in "percent normal" or in prothrombin ratio.

[Modern methods for the manufacture of therapeutic coagulation factors]. / Moderne Methoden zur Herstellung von Gerinnungstherapeutika.

In a modern therapy concept coagulation factor concentrates are widely used for prophylaxis of bleeding events and in intensive care medicine. In the past their use was limited by the risk of transmitting virus diseases to the patient. Therefore, it was a challenge to modern plasma fractionation to develop purification processes which are able to eliminate and inactivate viruses. At present several methods for virus inactivation are used; their efficiency is not finally proven. Practical experience exists with a method in which viruses are inactivated by heat treatment in solution. A similar process is used since more than 40 years to produce albumin and was proven to be safe. Today, all coagulation factor preparations can be treated by this inactivation method and produced in large scale. Together with a high degree of viruses elimination during the purification process the therapy with coagulation factors has become much safer.

Discrimination between fibrin and fibrinogen by a monoclonal antibody against a synthetic peptide.

Circulating soluble fibrin, observed in the blood of patients with ongoing intravascular coagulation, is generated from the plasma protein fibrinogen by the limited proteolytic action of thrombin. We report the production of a monoclonal antibody that discriminates between fibrin and fibrinogen in blood. The synthetic hexapeptide Gly-Pro-Arg-Val-Val-Glu, representing the amino terminus of the alpha chain of human fibrin, was used as immunogen. This hexapeptide is located within the A alpha chain of fibrinogen but becomes the amino terminus of the fibrin alpha chain, after fibrinopeptide A is removed by the action of thrombin, and thus becomes accessible for antibody binding. The monoclonal antibody we have prepared can discriminate between fibrin and fibrinogen and thus can be used in assay systems to quantitate soluble fibrin or, potentially, to image fibrin-rich thrombi.

The action of bovine spleen cathepsins B and D on the cytoplasmic ribonuclease inhibitor from rat liver.

The inactivation by the lysosomal cathepsins B or D of the cytoplasmic neutral ribonuclease inhibitor has been investigated with respect to the required amounts of cathepsin, optimal pH and time course. With a pH optimum between 5 and 5.5, a possible role of these endopeptidases in regulating the inhibitor and, concomitantly, the ribonuclease and RNA concentrations in the cell is discussed.

On the specificity of bovine spleen cathepsin B2.

The specificity of bovine spleen cathepsin B2 has been investigated by means of some natural oligo- and polypeptides, i.e. glucagon, melittin, insulin A and B chain, bradykinin, angiotensin I and II, oxytocin ACTH, clupein and salmin. The enzyme is primarily a carboxypeptidase which hydrolyzes peptide linkages of most amino acids common to proteins. In addition, cathepsin B2 displays amidase and esterase activity without requiring a free carboxyl group. The main pH optimum is between 4 and 5, in some cases higher.