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Biomedical subjects

U T Seyfert

Publications and source records attributed to U T Seyfert.

15 recordsLinked to original sources
PubMed1991

The role of protein C as an inhibitor of blood clotting during extracorporeal circulation.

The plasma levels of protein C, AT III, the perioperative administration of fresh frozen plasma (FFP) and AT III concentrate were compared under the use of various drugs in a randomized, prospective double-blind study in 40 patients in whom an aortocoronary bypass operation was carried out. We formed four groups of ten patients: group A served as a control group, group B received a prostacyclin (PGI2) infusion of 10 or 20 ng/kg/min, group C high-dose aprotinin substitution, and group D was treated with a combination of prostacyclin and aprotinin. After an initial short-term rise in the inhibitors protein C and AT III, there was a fall in all groups in the further course of extracorporeal circulation. The initial preoperative values were reached again on the morning of the first postoperative day. This indicates a raised turnover and in association with this a raised rate of elimination of these factors caused by an increased thrombin activation during the extracorporeal circulation which cannot be prevented by the usual heparinization. Whereas prostacyclin had no effect on our results mediated by thrombocytic mechanisms, use of aprotinin led to a significant saving in the requirement for perioperative fresh frozen plasma and AT III substitution therapy. A clinical advantage of prostacyclin and aprotinin combination was not observed. In view of our results (individual analyses were mainly in the normal range), we consider that AT III and fresh frozen plasma should not be substituted routinely during or after extracorporeal circulation.

Aged↗
PubMed1991

Comparison of blood biocompatibility during haemodialysis with cuprophane and polyacrylonitrile membranes.

Clotting within the dialyser is one of the most significant clinical parameters of biocompatibility. A study was designed to evaluate the biocompatibility of two different dialysis membranes (cuprophane and polyacrylonitrile) during therapy with conventional heparin. Transient leukopenia during cuprophane but not during polyacrylonitrile haemodialysis was observed, and elastase release using polyacryonitrile membranes was reduced (P less than 0.001). An elevation in F VIII:C activity during cuprophane haemodialysis has to be taken as an indication of endothelial disturbances. There was a significant (P less than 0.001) platelet activation (beta-thromboglobulin) and combined thrombin/plasmin generation using cuprophane membranes. This new synthetic polyacrylonitrile membrane inactivates the clotting in an extracorporeal system to a sufficient degree and allows a reduction in dosages of heparin. Platelet activation, platelet turnover, disturbances of endothelium, fibrinolysis activation, and granulocyte activation are reproducible parameters of a described interaction model. They also permit a comparison of different haemodialysis membranes.

Acrylic Resins↗
PubMed1991

Contributions to biorheology during hemodialysis.

Thrombogenicity is the property of a foreign surface to induce clotting processes or formation of aggregates after contact with blood. Beside the sort of anticoagulation patient's prethrombotic state, rheological factors as well as physicochemical properties of foreign membranes decisively influence thrombogenicity. We examined the influence of chronic renal failure and different hemodialyzers and blood transfusion therapy during hemodialysis on hemorheological parameters. Different membranes cannot be discriminated by the used hemorheological parameters. We clearly could demonstrate the close relationship between the hemofiltration rate and an increase of viscosity. Blood transfusion therapy or elevated hematocrit in combination with increased hemofiltration rate have influence on the flow behaviour of blood, especially in disturbed microcirculation.

Biocompatible Materials↗
PubMed1991

[Therapeutic use of fresh plasma and "virus-safe" plasma].

The use of plasma and factor concentrates for the treatment of coagulation disorders is well established, but many questions remain. The indications for fresh frozen plasma are still not clearly established and excessive use is rampant. The safety of all blood products has not yet been firmly established. Peer review of transfusion practice in a hospital can be achieved by a Hospital Transfusion Committee. The review and analysis of the statistical reports of the transfusion service and strategies for enhancing quality of patient care will be presented.

Algorithms↗
PubMed1991

Clinical relevance of biological incompatibility and role of a central register.

Different aspects relevant for the assessment and characterization of biomaterials are presented. Quite a number of basic concepts that play an important role when detecting unwanted adverse effects of drugs have to be taken into consideration when registering and evaluating unwanted effects of biomaterials. The institutionalization of the Central Bioregister at the University of Saarland is described. This Bioregister is a so-called "spontaneous" ad hoc recording system whose efficiency depends largely on the collaboration of physicians. Thus, the efficiency and rationality of the use of biomaterials can certainly be improved. The possibility of registering even rarely occurring unwanted effects as well as new indications will result in and allow a more general and/or a more specific therapy, depending on the biomaterial.

Adverse Drug Reaction Reporting Systems↗
PubMed1990

The development of a central register for side effects of biomaterials.

Examination of the interaction between biomaterials and tissues from a clinical realistic as well as scientific viewpoint to complement the highly advanced experimental and biochemical basis research is an undertaking that has suffered a considerable amount of neglect in the past. Attempts to realize internationally a Central Registry for documenting clinically relevant side effects will be reported in detail. Implementation of the registry involves the review of present literature (prospective clinical studies, retrospective studies and case reports). An "incompatibility incident report/questionnaire" has been developed according to the guidelines of the "Report on Pharmacological Side Effects" of the Pharmaceutical Commission of the German Medical Association. The aims of registering and evaluating these reports will be demonstrated and discussed in detail.

Biocompatible Materials↗
PubMed1990

Platelet-tumor cell interaction.

Several reports have appeared with regard to the potential role of platelets in tumor cells metastasis. Our in vitro studies with colon tumor cells in normals and in patients give some evidence against platelet aggregation as the determinant factor in tumor cell invasion and metastasis. Dimethylhydrazine induced colon tumors in Wistar rats demonstrate characteristic features of tumor cell dissociation in the invasion line and changes in intercellular adhesion.

Actin Cytoskeleton↗
PubMedDate not supplied

[Ultrasound study of the newborn hip: results and consequences].

From October 1985 to September 1988 3000 neonatal hips were controlled clinically and by ultrasound. 3% of those needed an immediate treatment. In 45 of these 90 hips there were no directing clinical signs or suspicious hints in the family history or during the course of pregnancy. This means, that these inconspicuous cases would not have got their necessary therapy without the ultrasound-screening. Thus the results of this investigation supports the call for the general ultrasound-screening of the neonatal hip.

Female↗
PubMedDate not supplied

Alport's syndrome--an autoaggressive immunopathy?

Hereditary chronic nephritis, or Alport's syndrome, is a pathologically and clinically very inhomogeneous disease, the main features of which are hereditary nephropathy combined with deafness of varying degrees. Our experience with 18 patients from 6 families demonstrates the variability in the manifestation of the clinical defect syndromes with oculo-oto renal involvement. In the majority of our cases, terminal renal failure was diagnosed. 7 patients are undergoing chronic intermittent hemodialysis, and 4 patients survive with a kidney transplant. Following kidney transplantation, histological changes in the sense of a recurrent glomerulonephritis were demonstrated in some cases. The existence of prevailing histocompatibility antigen DR 7 serves as a clue to the possibility of an underlying immunologic disorder. We calculate a relative risk of 6.0. The HLA-D region controls the expression of surface antigens. They are responsible for the communication with lymphoid cells. Defect immune response genes in combination with missing reaction to autoantibodies against glomerular basement membrane may lead to an increase of susceptibility for the disease.

Adolescent↗