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M Heiden

Publications and source records attributed to M Heiden.

30 records · Page 2Linked to original sources
PubMed1990

Comparison of different prothrombin complex concentrates--in vitro and in vivo studies.

The potency and tests for thrombogenicity were studied prospectively in 7 different (two lots of each brand, A-G) prothrombin complex concentrates (PCC). Human albumine (H) and a factor IX concentrate (I), served as controls. The potency of coagulation factors and inhibitors varied considerably. Two brands (E, F) contained no protein S, additionally one brand contained no protein C. Two preparations exhibited high amidolytic activities, especially towards the thrombin-sensitive chromogenic substrate S-2238, in vitro. These activities could be quenched in part by the addition of hirudin or antithrombin III. The heparin and antithrombin III content of the PCCs was significantly different, and, after addition of antithrombin III an increase of thrombin-antithrombin III complexes in 2 preparations (B, D) was observed in vitro. Additionally, three brands (B, D, F) caused more severe cardio-pulmonary reactions in rabbits, associated with an increase of fibrin split products for brands B and D. We conclude that the use of these preparations in patients, in whom an acquired protein C or S defect, or a hypercoagulable state, can be suspected, cannot be recommended.

Animals↗
PubMed1990

[Subcutaneous injection of desmopressin (DDAVP) for increasing factor VIII and von Willebrand factor in plasmapheresis].

Desmopressin (DDAVP) is an effective tool for increasing factor VIII (FVIII)/von Willebrand factor (vWF) in normal subjects and in patients with haemophilia A and von Willebrand's disease. There are a few studies utilizing DDAVP to increase the FVIII/vWF yield in plasmapheresis donors. In these studies, DDAVP was given either by intranasal administration or intravenous infusion. The aim of our pilot study was to investigate the subcutaneous (s.c.) injection of DDAVP in combination with double bag plasmapheresis. 8 donors with blood group A and 5 with O were given 0.4 micrograms/kg body weight DDAVP as a s.c. injection 30 min prior to the first donation. FVIII increased 3.7 and ristocetin cofactor 2.5 the initial value in the donors. In the plasma bags, a 3 (1st bag) and 3.5 (2nd bag) fold higher FVIII level was found, when compared with baseline levels. There was only a mild decrease of blood pressure, and serious adverse effects were not observed. Our data suggest that s.c. DDAVP may be more effective and especially suited for increasing FVIII/vWF yield in plasmapheresis donors.

Blood Donors↗
PubMed1990

[Quality control of prothrombin complex preparations: in vivo and in vitro findings].

Prothrombin complex concentrates (PCC) are frequently used for the treatment of acquired coagulation factor deficiencies. However, a major problem when using these preparations is their thrombogenic potential. Thus, the potency and tests for thrombogenicity were studied prospectively in 7 different PCC's. Human albumine and a factor IX concentrate served as controls. The potency of coagulation factors and inhibitors varied considerably, especially for proteins S and C. Two preparations exhibited high amidolytic activities in vitro. These activities could be quenched in part by the addition of hirudin or antithrombin III. Additionally, these two preparations caused more severe cardiopulmonary reactions in rabbits and an increase of fibrin split products. We conclude that the use of these preparations in patients, in whom an acquired protein C or S defect, or a hypercoagulable state, can be suspected, cannot be recommended.

Blood Coagulation Factors↗
PubMed1990

[Pharmacologic and clinical principles for rational anti-thrombotic preventive treatment with low molecular weight heparin].

Heparin exerts its anticoagulant function by accelerating the inhibitory effect of antithrombin III. Low molecular weight heparin (LMWH), which is derived from unfractionated heparin (UFH), exhibits marked anti-Xa activity and minor thrombin inhibition. It has an elevated bioavailability and longer half-life as to the anti-Xa clearance when compared to UFH. Platelet, endothelial and fibrinolytic effects are also involved in antithrombotic action. Clinical trials have shown that LMWH compared to UFH is an equivalent and even advantageous method of antithrombotic prophylaxis in surgical patients and has also a minor risk of bleeding.

Blood Coagulation Tests↗
PubMed1990

Effects of garlic on blood fluidity and fibrinolytic activity: a randomised, placebo-controlled, double-blind study.

In summary, it can be said that the improvement of blood fluidity and the simultaneous increase in fibrinolytic activity are an ideal complement. While the increase in fibrinolytic activity supports the physiological reparation process in the microcirculation, the improvement of blood fluidity produces an increase in capillary perfusion that has, in some way, a cleaning effect, with a 'purification' of the microcirculation.

Adult↗
PubMed1988

Plasminogen: a brief introduction into its biochemistry and function.

Human plasminogen is a beta-globulin (2% carbohydrate, molecular weight 90 KD), which in its native form has NH2-terminal glutamic acid (Glu-plasminogen) whose primary structure is known (31, 37, 38). From human plasma plasminogen can easily be isolated by affinity chromatography techniques (10, 25, and Table 1). Plasminogen is synthesized in many organs. The production site of the zymogen may be the liver (21), the eosinophiles (3) or the kidney (15). The plasma-plasminogen level is low in newborns (22) and even lower in the premature infant (2). In healthy adults it is found in plasma or serum in a concentration of 200 mg/l (= 2 microM, 22, 39). The half-life of the native (Glu-) plasminogen is 2.24 +/- 0.29 days (6). Two types of Glu-plasminogen occur in human plasma, which differ in their carbohydrate composition as well as in their content of sialic acid. Genetic variants (see Mayr, 3.1.); of plasminogen have been reported (16) after isoelectric focusing of human plasma in polyacrylamide gels. Three patterns were found, two completely different and the third most likely a mixture of the other two. Characteristical functional properties of plasminogen are related to its molecular structure, e.g. its in vivo specificity for fibrin in contrast to the fairly unspecific in vitro activity of plasmin. Glu-plasminogen is easily converted by limited plasmic digestion to modified forms with NH2-terminal lysine, valine or methionine, which are commonly designated "Lys-plasminogen" displaying a plasma half-life time of 0.8 days.(ABSTRACT TRUNCATED AT 250 WORDS)

Carbohydrate Conformation↗
PubMed1988

Reference values and variability of plasminogen in healthy blood donors and its relation to parameters of the fibrinolytic system.

During a survey of four month's duration the following parameters were determined in 43 healthy blood donors (22 males, 21 females; mean age 29 years/20-49/): plasminogen activity, plasminogen concentration, alpha 2-antiplasmin (alpha 2-AP) activity, alpha 2-AP concentration, tissue type plasminogen activator (t-PA) activity, t-PA concentration, plasminogen activator inhibitor--I (PAI-I) activity, AT III activity, AT III concentration and heparin cofactor II (HC II) activity. Normal values including standard deviation (x +/- 2s) were: plasminogen activity: 96.3% (65.9-126.8), plasminogen concentration: 12.2 mg/dl (7.7-16.8), alpha 2-AP activity: 99.9% (83.8-116), alpha 2-AP concentration: 108.1% (84.5-131.8), t-PA activity: 0.85 IU/l (0.0-1.92), t-PA concentration: 10.3 ng/ml (2.5-18.1), PAI-I activity: 15.2 AU/ml, AT III activity: 111.4% (87.8-134.9), AT III concentration: 31.6 mg/dl (24.2-39.1) and HC II activity: 110.7% (81.4-140.0). Concerning plasminogen values no sex related difference could be stated. Women who were smokers and used oral contraceptives tended to present elevated t-PA activity levels due to a lower activity of PAI-I, although this tendency was not significant. Determining concentration and activity of components in the fibrinolytic system plays an important part in the diagnosis, therapy and prognosis of thrombophilic disorders.

Adult↗
PubMed1988

Characterization of commercially available plasminogen preparations in vitro: purity and reactivity.

Three different commercially available plasminogen preparations (Immuno-, Kabi-, and Behring-plasminogens) were examined regarding purity and reactivity to different activators (high molecular weight [HMW] or low molecular weight [LMW] two-chain urokinase type plasminogen activator [tcu-PA], single chain urokinase type plasminogen activator [scu-PA], tissue type plasminogen activator [t-PA], and streptokinase [SK]). The Immuno-preparation was a Lys-plasminogen, commercially available for therapeutical use, whereas the research reagents for KabiVitrum and Behringwerke were Glu-plasminogen. Activity data provided by the manufacturers correlated well with our findings. Also a good correlation of reactivity to activators measured with a chromogenic substrate and on fibrin plates could be observed. The Immuno-plasminogen showed a minimum contamination with plasmin which has to be taken into consideration for the interpretation for its apparently higher activation by plasminogen activators compared to the plasmin-free plasminogens. Further in vitro and in vivo research has to be performed to find out criteria for a practicable scheme of administration of fibrinolytic agents for therapeutical thrombolysis.

Electrophoresis, Polyacrylamide Gel↗
PubMed1985

Is it possible to maintain a normal glutathione level in lenses in vitro?

In most types of experimentally induced cataracts, glutathione (GSH) content decreases considerably before the onset of opacity. GSH may provide a protective function for protein SH groups by scavenging oxidative products that may impair lens metabolism. To avoid impairment of lens metabolism by decreased levels of GSH it may be possible in vitro: (1) to stimulate GSH synthesis by enrichment of the incubation medium with the amino acids necessary for GSH synthesis or (2) to enrich the incubation medium with the tripeptide itself so that it can be taken up by the lens. Both approaches were investigated with bovine lenses. Lenses were incubated in pairs in a salt solution without carbohydrates, so as to deplete lens of GSH. Following starvation, one lens of each pair was incubated for recovery in TCM 199 enriched with MgSO4 and the three amino acids of GSH; the other lens was put into a freshly prepared salt solution. After 6 h, lenses from the recovery solution contained more GSH than the other lenses. Addition of fructose-1,6-diphosphate to the medium enhanced this effect. When, after starvation, lenses were incubated in the presence of different amounts of GSH, GSH lens content rose, with the highest in those lenses incubated in a medium with a final molarity of 4 X 10(-3) M GSH. Therefore, incubation of lenses depleted of GSH in medium with either the amino acids of GSH or GSH itself appear to facilitate recovery of GSH content.

Animals↗
PubMedDate not supplied

Tissue factor is the only activator of coagulation in cultured human lung cancer cells.

It is a long-known principle that tumour cells tend to exploit the host's physiologic systems in order to get support in terms of, for example, nutrition, growth or metastasis. One of these physiologic systems is the blood coagulation cascade, which has been found activated in many tumour patients. The mechanisms of the activation of coagulation have been assessed in numerous animal and in vitro experiments, and the results appeared to point to several distinct activators. The present study used a large panel of different cultivated human lung cancer cell lines and experimental systems involving normal plasma, plasmas deficient of factors V, VII or X, purified coagulation factors II and X, recombinant tissue factor (TF), and specific inhibitory antibodies against factor VII and TF. The results provide strong evidence that there is no activator of coagulation besides TF in the wide array of lung cancer cells examined. However, this work reveals a striking variability of TF content among the cell lines. This might explain ambiguous results of clinical trials of anticoagulation as an adjunct to antineoplastic therapy in lung cancer. By sensitive diagnostic tools like the plasma thrombin-antithrombin complex levels it might be possible to select patients with activated coagulation, who might benefit from anticoagulation.

Antibodies↗