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Biomedical subjects

B Ernst

Publications and source records attributed to B Ernst.

At least 55 records · Page 3Linked to original sources

A newly developed LDL-binding material.

Results of in vitro and ex vivo experiments with a newly developed LDL-binding material are presented. This material consists of macroporous bead cellulose which is capable to bind selectively LDL. LDL-cholesterol is considerably decreased after contacts of plasma or serum samples with this bead cellulose. On the other hand high density lipoproteins (HDL) and other plasma components (proteins, enzymes, electrolytes, and metabolic substances) remained high or unchanged. Triglycerides (TG)--transported by very low density lipoproteins--are also bound up to a certain degree. 1 g of the adsorbent wet mass binds at least 20 mg cholesterol. The capacity suffices to decrease two- to threefold increased cholesterol and LDL plasma levels to the low normal range following passage of the sevenfold plasma volume' through two the three LDL adsorbent columns (results of perfusion experiments). In vitro and dog experiments revealed only slight drops of the hemolytic capacities of the classic complement pathway and moderate decreases of the alternative one. But no detectable side effects were noticed in the dog experiments.

Adsorption↗

Encapsulation of liver microsomes--a further procedure for detoxication.

Due to their partial permeability and their good mechanical properties, the symplex capsules are technically suited for an application in extracorporal detoxification. By this newly developed procedure the activity of encapsulated enzymes is considerably increased; thus, application for extracorporal detoxification seems to be advisable.

Animals↗

[An improved method for the microencapsulation of liver microsomes for use in extracorporeal detoxication].

Rat liver microsomes were microencapsulated in a pure aqueous medium by means of a new technique. The wall of the microcapsules consists of a semipermeable simplex membrane which is stabilized mainly by electrostatic interactions between a polymeric polyanion (sodium cellulose sulphate) and a polymeric polycation (polydimethyldiallylammonium chloride). The metabolic as well as the mechanic parameters of the microcapsules could be markedly improved by separating the metabolic (liver microsomes) from the membrane component (sodium cellulose sulphate) in such a way that two distinct compartments are formed during the preparation of the microcapsules.

Animals↗

Low density lipoprotein binding by macroporous bead cellulose.

Cellulose of a certain macroporous structure is capable of binding selectively low density lipoproteins (LDL) whilst maintaining high density lipoprotein (HDL) levels. It was ascertained that the porous structure of the cellulose causes binding of LDL and that also diffusion processes play a role. To a certain extent special bindings such as hydrogen bonds between cellulose and LDL and/or hydrophobic interactions may furthermore be of importance for the LDL fixation.

Adsorption↗

[Hemostasis monitoring in intensive therapy--studies using resonance thrombography].

The resonance-thrombogram (RTG) is the result of a new investigation method verifying the clotting process as a whole. It provides a far reaching breakdown of the main factors of coagulation and thus a means for diagnosing and treating coagulation disorders. A special field of application is indication and control of therapy in cases of disseminated intravascular clotting and hyperfibrinolysis in intensive care. Simple operation, relatively quick results and the possibility of rapid diagnosis using the RTG curve appear to make it suitable as a bed-side method of investigating blood coagulation.

Blood Coagulation Tests↗

A first screening for hemocompatibility of a universal support for selective and specific hemoperfusion.

A modified filmadsorber is presented, intended to be used for selective and specific hemoperfusion. It consists of a spirally wound cellulose nitrate film, onto which--after chemical activation with sodium periodate--albumin is bound, stabilized, sterilized and activated with glutaraldehyde. Various bioactive ligands containing amino groups can be coupled to this support. A subsequent treatment with dimethylamino borane stabilizes the bonds between cellulose nitrate, albumin, glutaraldehyde and ligand. Columns in which a second layer of albumin is bound to the support as a model for a bioactive ligand were first screened for hemocompatibility using rabbits. Leukocyte, thrombocyte and hematocrit behaviour during hemoperfusion showed that hemocompatibility of the support was good.

Adsorption↗

[The status of prazosin in therapy of chronic heart failure].

Cardiac dysfunction and neurohumoral dysregulation show that the administration of vasodilators is reasonable in a cardiac insufficiency which is therapy-refractory against glycosides and saluretics. The alpha 1-blocker prazosin is a potent substance. On the basis of haemodynamic investigations of 55 patients the acute effects are demonstrated. Depending upon the degree of the cardiac insufficiency and the sympathetic dysregulation--measured at the behaviour of the resistance--the acute effects are convincing in more than 60% of the patients. For the long-term course patients with unequivocal initial improvement are suitable. This group can undergo a satisfactory therapy for a longer time by means of a carefully increased dosage, by corrections of the application of saluretics and by short interruptions of therapy and by the change of the dilator, respectively, or by an additional administration of another vasodilator. In the total spectre of the vasodilators which are administered in cardiac insufficiency prazosin occupies one of the first places.

Cardiomyopathy, Dilated↗

[Blood coagulation factors and proteinase inhibitors in cytostatic therapy of acute leukemia].

In 64 patients affected with acute leukaemia (51 patients with acute non-lymphatic leukaemia and 13 patients with acute lymphatic leukaemia) extensive investigations of blood coagulation were made during cytostatic therapy. The following conspicuous changes of haemostatasis could be observed in making the diagnosis: Lowered quick value and shortened PTT, increased fibrinogen, fibrinopeptide, A, alpha 1-antitrypsin and alpha 2-macroglobulin, diminished plasminogen and plasma fibrininectin. According to TAD (VP) protocol the induction therapy leads to hypercoagulability which can be recognized by an increase of fibrinopeptide A, coagulating factors and shortening of PTT. During the therapy with L-asparaginasis procoagulatoric as well as thromboprotective coagulating proteins are diminished. A dense laboratory control enables those disturbances of haemotasis caused by disease or therapy to be separated and contributes to preventing complications during the cytostatic induction therapy.

Adult↗

[Production of immobilized urease adsorbed on polystyrene granules].

We prepared adsorption immobilized Urease (E.C. 3.5.1.5) with a special method of polymer coating of polystyrene granulate as a matrix, and by subsequent adsorption of two different urease products (AWD Dresden, DDR, 3 U/mg, and Serva, Heidelberg, BRD, 41 U/mg). We obtained the strongest activity (4.0 mumol.g-1.min-1) with immobilisates on polystyrene in comparison with polyvinylchloride, and polyurethane layers, if we used AWD urease (PS, PVC, PUR). By using Serva urease we obtained products with a manyfold of activity (12.8 mumol.g.min-1). This high activity enables us to utilize adsorption immobilized urease for the detoxification of biological fluids.

Ammonia↗

[The estimation of the hemocompatibility of synthetic polymers by in vitro determination of thrombocyte adhesion under standardized conditions].

In vitro tests are necessary in the biomaterial investigation to the characterization of blood-material-interactions. The platelet adhesion rate on these layers were tested concerning the valuation of the haemocompatibility of the basic-polymers polyurethane (PUR), polyvinylchloride (PVC), and polystyrene (PS) in two different worked test chambers. The sequence PUR greater than PVC greater than PS of their haemocompatibility were shown with sufficient reproductiveness of the test results. Such chamber tests allow to standardise the haemocompatability considerably.

Biocompatible Materials↗

[Extracorporeal blood circulation in the unanesthetized free-moving rabbit--an animal model for biocompatibility studies].

The rabbit is suitable as a basis model for the extracorporal circuit (ECC) in long-term test (20 days). A decrease of the leucocytes and platelets is established already in the blank test qualified by catheter material and pumping influence. This effect can be compensated by the rabbit in long-term test. The typical decrease of the leucocytes and platelets does not show any significant alteration during many test days independent of the number of tests which were carried out in one rabbit (blank test and hemoperfusion). A hemoperfusion across activated carbon--independent of the albumin coating--leads to a significant decrease of the leucocytes in comparison to the blank test. This rabbit model is well-suitable for biocompatibility investigations respectively also for effective investigations of detoxication techniques taken as a basis of our results.

Animals↗

[Detection of factor XIII deficiency in acute leukemia with resonance thrombography].

In 16 patients affected with acute leukemia (7 patients with acute lymphatic leukemia and 9 patients with acute myeloid leukemia) the resonance thrombogramme was recorded during cytostatic induction therapy, coagulation factor XIII (subunit XIII-A, XIII-S) and further hemostasiological parameters were determined. Subunit XIII-A was lowered to 36%, subunit XIII-S to 65% and the fibrin formation time of the resonance thrombogramme was extended to 9 minutes. There exists a negative correlation between component XIII-A and fibrin formation time r = -0.48 (p less than 0.01). The influence exerted by diminishing factor XIII and fibrin(ogen) splitting products on the fibrin formation time was investigated in in-vitro tests. A diminution of factor XIII below 10% will extend the fibrin formation time to about 10 minutes, an increase of fibrin(ogen) splitting products to 100 micrograms/ml to about 3 minutes.

Adult↗

[Short-term lysis of venous thrombosis with ultra-high streptokinase doses].

11 patients with deep pelvic and leg vein thrombosis were treated with ultra-high streptokinase infusion, 1.5. 10(6) IE streptokinase per hour over a six hour period. Opening of the vein occlusion was achieved in four cases completely and in five cases partially. The frequency of complications was lower at short-time thrombolysis with ultra-high streptokinase infusion in contrast to long-time thrombolysis. Bleedings did not occur. Because of the slight side effects ultra-high streptokinase infusion is an alternative in the fibrinolytic treatment of risk patients with pelvic and leg vein thrombosis.

Adult↗

[Evaluation of clinical efficacy of platelet substitution in acute leukemia using resonance thrombography].

For evaluating the clinical effectiveness of thrombocyte substitution, the resonance thrombogram was registered before and after thrombocyte substitution in 50 patients with acute leukemia and the increase of thrombocytes (corrected increment) determined. Thrombocyte substitution led to a significant diminution of the platelet amplitude (p less than 0.01) and platelet value. The highest value of these alterations of parameters was reached 1 hour after transfusion, it was somewhat lower after 24 hours, yet the initial value was not reached again. Correlations could be found to exist between the platelet amplitude and the corrected thrombocyte increase 1 hour and 24 hours after transfusion. The resonance thrombography enables the successful control of thrombocyte substitution to be made and it is suitable for monitoring hemostasis in severe thrombocytopenia due to production.

Acute Disease↗