[The "TAS-Analyzer"].
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Evaluation Studies as Topic↗
Biomedical subjects
U T Seyfert
Publications and source records attributed to U T Seyfert.
Quality of fresh-frozen plasma during storage.
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Blood Preservation↗
[Hemocompatibility of various synthetic granulates].
The adherence of platelets to different polymer granulates was examined in a perfusion chamber filled with platelet-rich plasma. The surface area of each of the granulates was of a standardised size. The results were compared with those found for a non-thrombogenic and a highly thrombogenic foreign-body surface. The three polymers examined-Cryolite, Styrolux and Zylar-must be considered non-thrombogenic. Platelet adherence to these substances is significantly less (3%) than that to a highly thrombogenic surface such as glass (95%). The three materials did not differ in terms of platelet adherence, and would appear to be suitable potential materials for use in cell separators.
Biocompatible Materials↗
[Hemocompatibility testing of polymers].
Haemoincompatibility induced by contact with artificial materials is a major obstacle to further development of artificial organs and accounts for much of morbidity in circumstances when the blood is circulated through an extracorporeal system or a catheter is placed. Material's testing was performed using different models and a score system (0-60 scorepoints) was developed. Our models can characterize ex vivo haemocompatibility of different polymers. Flow characteristics and preanalytical effects (e.g. anticoagulants) may not be neglected.
Blood Banks↗
[Hypercoagulation caused by heparin-associated type II thrombocytopenia].
The immunological type of heparin-associated thrombocytopenia (HAT II) is a severe complication of heparin treatment and is associated with arterial and venous thrombosis. Only patients with absolute thrombocytopenia have prompted suspicion of HAT in clinical practice. We report on a 44-year-old male who developed thromboembolic episodes after coronary angiography such as reinfarction and thrombotic episodes of A. brachialis. Fibrinolytic therapy combined with i.v. unfractionated heparin treatment was the therapy of choice and was followed by severe further thromboembolic adverse effects. Besides an impaired fibrinolytic response and elevated antiphospholipid antibodies, we diagnosed HAT type II in HIPA and ELISA (Stago. Boehringer-Mannheim). This special patient had platelet counts within a normal range, when developing the thromboembolic episodes. It appears that the normal platelet count during the thromboembolic episodes reflect a relative thrombocytopenia. From a clinical point of view we recommend the use of a lab panel to exclude HAT type II in patients with thromboembolic episodes under therapy with fractionated or unfractionated heparin. Platelet counts within a normal range are not absolute exclusion criterion for HAT II.
Adult↗
Effects of high-dose aprotinin on renal function in aortocoronary bypass grafting.
BACKGROUND: To reduce blood consumption in cardiac surgery, aprotinin has been widely used for years. Because aprotinin is metabolized in the kidney, damage of the renal system has been discussed. METHODS: To study these possibly unfavorable effects of aprotinin, a prospective, randomized, placebo-controlled study of 20 patients undergoing aortocoronary bypass operations was performed. A placebo group P was compared with group A, in which patients received high-dose aprotinin according to the "Hammersmith" regimen. Renal function was assessed for 5 postoperative days using sodium dodecyl sulfate gel electrophoresis and quantitative protein analysis of the urine. RESULTS: During and after the operation, temporary renal dysfunction was found in all patients, with a substantial increase of all investigated indices. The alpha 1-microglobulin level in the urine was significantly increased in the aprotinin group for 5 days in comparison with the placebo group, with a maximum on the third postoperative day (64.8 +/- 13.7 versus 21.0 +/- 6.5 mg/L; p < 0.05). Similarly, after sodium dodecyl sulfate-polyacrylamide gel electrophoresis, the bands of proteins filtrated in the renal tubular system were almost tripled in the aprotinin group 5 days postoperatively (5.0 +/- 0.8 versus 2.1 +/- 0.2; p < 0.05). Although urine production was significantly increased in group A (4789 +/- 580 versus 3653 +/- 492 mL/24 h postoperatively; p < 0.05), no relevant changes in serum or urine creatinine levels could be observed in either group. CONCLUSIONS: Patients undergoing aortocoronary bypass operations demonstrate a temporary renal dysfunction. Aprotinin impairs renal function in addition by overloading the tubular reabsorption mechanisms. Patients with normal renal function preoperatively--as were included in this study--are able to compensate for both the perioperative renal dysfunction caused by the extracorporeal circulation and the additional tubular damage due to aprotinin.
Aged↗
Possible clinical effects of the interaction of hemodialysis membranes with adhesion proteins.
In this study data obtained in an in vitro hemodialysis model are related to various parameters measured in patients' plasma during hemodialysis in a clinical crossover study. In vitro, blood from healthy volunteers was dialyzed under standardized conditions using the capillaries Fresenius MTS C (Cuprophane) and Hospal AN 69 (Polyacrylonitrile). Following dialysis, surface bound proteins were eluted with saline, 1 M Tris and 2% SDS, and analyzed by immunoblotting. Depending on the capillary, different protein patterns could be identified in the eluates. Intact forms of adhesion proteins were predominantly (fibrinogen) or exclusively (vitronectin) found in PA eluates. In contrast, low molecular weight products of fibrinogen as well as high molecular weight components containing antithrombin III (AT III) were present in CP eluates. Their presence may reflect fibrinolytic and procoagulatory activity during dialysis with CP capillaries. A microscopic investigation of CP membranes demonstrated fibrin lined platelet conglomerates. In the plasmas of patients dialyzed with CP capillaries high D-Dimer concentrations were found. We also noticed that during dialysis with PA membranes less heparin was consumed than during dialysis with CP membranes. Our study showed a good correlation of the observations in the vitro system and the measurements in patient samples.
Adsorption↗
Heparin-associated thrombocytopenia (HAT)--still a diagnostic and therapeutical problem in clinical practice.
Type II of heparin-associated thrombocytopenia (HAT) is well known, but the cardinal symptom, thrombocytopenia, is rarely adequately considered. Serious and potential lethal complications such as pulmonary embolism, cerebral stroke, or limb gangrene are often falsely regarded as insufficient anticoagulation. Guided diagnosis and therapy are of vital importance for the patient's outcome. Based on the experience of patients with HAT Type II treated in the intensive care unit, a diagnostic and therapeutic approach to the cardinal symptom thrombocytopenia is presented. A recently developed heparin-induced platelet activation assay (HIPAA) seems to be a highly sensitive laboratory test. The first therapeutic principle in case of presumed and diagnosed HAT is the cessation of unfractioned or low-molecular-weight heparins. ORG 10172 (Orgaran), a low-sulfated heparinoid with a low cross-reactivity (10%) to heparins, can be regarded as the most effective anticoagulant in patients with HAT Type II.
Adult↗
HES 200/0.5 is not HES 200/0.5. Influence of the C2/C6 hydroxyethylation ratio of hydroxyethyl starch (HES) on hemorheology, coagulation and elimination kinetics.
The plasma clearance of hydroxyethyl starch (HES) depends on the initial molecular weight and the degree of substitution. So far, little attention has been paid to the clinical relevance of the C2/C6 substitution ratio of hydroxyethyl starch. 10 patients with cerebrovascular circulatory disturbance received hemodilution therapy for 10 days, consisting of 10% HES 200/0.5 (mean molecular weight 200 kD, degree of substitution 0.5) with a C2/C6 ratio of 13.4. A second group of 10 patients received a starch solution with identical initial molecular weight and degree of substitution but with a C2/C6 ratio of 5.7. After the administration of a single dose, no significant differences between the two groups were observed. After repeated administration, significant differences could be detected in hemorheology, coagulation and elimination (p < 0.01). The larger C2/C6 ratio led to a higher intravascular mean molecular weight (95 vs. 84 kD), which in turn led to a higher increase in serum concentration during the therapy (14.7 vs. 8.6 mg/ml). Hematocrit was lowered more (-30.5 vs. -23.5%) and plasma viscosity was increased more. There was also a more pronounced increase in partial thromboplastin time (+30% vs. +13%) and a factor of 2 larger decrease of factor VIII/von Willebrand factor-complex (p < 0.01), which exceeded the dilution effect. The higher C2/C6 ratio of HES 200/0.5/13.4 slows down enzymatic degradation. After repeated administration of this starch, large molecules accumulate which are inefficiently degraded. The same effect has been observed after therapy with highly-substituted HES. This accumulation of large molecules leads to a beneficial longer lasting volume effect. The disadvantages include an increase in plasma viscosity and coagulation disturbances, which cannot be explained with the respective dilution effect alone. For these reasons, the C2/C6 ratio is of clinical relevance and should be included in the product labeling in the future.
Alkylation↗
Determination of factor XIII activity by a new photometric assay in plasma and platelets of healthy blood donors.
Crosslinking of fibrin monomers by activated factor XIII (F XIIIa) is a final event in blood coagulation. So the fibrin clot gains mechanical stability and resistance to plasmin degradation which is thought to be essential for normal blood clotting and wound healing (1-3). In addition, changes in plasma F XIII activity were found in several state of disease such as collagenoses, inflammatory bowel diseases, leukemias, subarachnoidal bleeding and delayed fracture healing (4-12). Because approximately 50% of the potential F XIII activity in plasma are present in platelets (1), the additional determination of F XIII activity in platelets is of clinical interest especially concerning platelet transfusions that may exert an additional benefit due to simultaneous substitution of platelet-bound F XIII. The latter differs from plasma F XIII as a dimer containing only a-chains (a2) compared to the plasmatic tetramer carrying additional b-chains (a2b2). We applied a recently described photometric assay suitable for the routine laboratory after adaption to an autoanalyser to determine F XIII activity in plasma and platelets of 64 healthy blood donors.
Adolescent↗
Celite and kaolin produce differing activated clotting times during cardiopulmonary bypass under aprotinin therapy.
Since the introduction of the proteinase inhibitor aprotinin in cardiac surgery, a strong increase of the activated clotting time (ACT) during the extracorporeal circulation phase (ECC) was reported in many clinical studies, but with a lack of correlation between ACT and heparin concentration. In searching for a cause of this inconsistency we investigated different surface activators of the ACT in a clinical study. During ECC ACT was measured in parallel, using a Hemochron device and corresponding tubes (nominally 12 mg celite activator) for celite ACT, and a HemoTec device with corresponding double tubes (nominally 0.1 ml kaolin activator) for kaolin ACT. Under the conditions of ECC, the kaolin ACT values (482 +/- 145 sec) were significantly lower than the celite ACT values (985 +/- 267 sec). These results were confirmed in ex-vivo experiments using an activated partial thromboplastin time (aPTT) model. With heparin alone, aPTT activated with celite and kaolin were similar. Including aprotinin in this model, the celite aPTT showed no correlation to the heparin concentration, whereas the kaolin aPTT remained well correlated to the heparin concentration and similar to the values without aprotinin. With aprotinin alone there were no changes of the aPTT times, whereas the celite ACT times were without any correlation. Our results indicate that using kaolin instead of celite the ACT measurements under aprotinin therapy stay in the same ranges as without application of aprotinin: aprotinin has no detectable influence on kaolin-activated ACT. In our opinion, kaolin should be used as the surface activator for ACT measurements under the conditions of ECC, heparinization, and aprotinin therapy.(ABSTRACT TRUNCATED AT 250 WORDS)
Aprotinin↗
[Septic-toxic heart failure as a result of a heparin-induced thrombocytopenia with "white-clot-syndrome"].
A patient is presented who developed pulmonary artery embolism and thrombocytopenia with various arterial clots several days after an ankle joint osteosynthesis, which finally caused the amputation of the right arm. Unfractionated heparin was applied for the prevention of postoperative thrombosis. Obviously as a consequence of the liberation of toxic metabolites from the gangrenous lower arm, the patient developed septic shock which was exacerbated by a severe pneumonia caused by methicillin-resistant S. aureus bacteria (MRSA). Laboratory investigations showed an antibody (IgG) induced thrombopenia mediated by all low molecular weight and unfractionated heparins. By eliminating heparin and further treatment with a low molecular weight heparinoid (ORG 10,172), platelet count rose sufficiently and thrombotic process ceased completely. Septic shock was successfully treated by fluid replacement, antibiotics and inotropic substances.
Adult↗
[Indications for fresh frozen plasma: evaluation of virus inactivating preparations].
When no specific factor concentrate is available fresh-frozen plasma (FFP) is indicated in the treatment of clinically relevant hemorrhagic diathesis. These disorders include congenital factor V and XI deficiencies, multiple factor defects, as disseminated intravascular coagulation and severe liver disease, and patients receiving massive transfusions, when bleeding occurs and severe abnormalities on coagulation testing are evident. FFP is beneficial when used with plasma exchange in thrombotic thrombocytopenic purpura and related disorders. Various virucidal treatments including solvent-detergent (SD), photoactivated dyes (methylene blue) or pasteurization have been evolved to improve virus safety of human plasma. More extensive studies to demonstrate efficient virus inactivation in plasma have been performed with SD compared to other methods. On the other hand, the use of single-donor FFP in methylene blue treatment is possibly superior to pooled plasma which is processed according to the SD procedure. Pasteurization enables the inactivation not only of lipid-enveloped but also of non-lipid-enveloped viruses. Virucidal treatment of plasma may cause alterations in clotting factors, fibrinolysis and protease inhibitors; however, the currently achieved recovery of procoagulant activities is approximately comparable with that found in untreated FFP. The toxicity of virucidal additives is reported to be negligible since manufacturing includes a removal procedure (SD) or comparably low amounts (methylene blue) are used in inactivation treatment.
Antiviral Agents↗
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↗
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↗
Factor XIII deficiency in adult polycystic kidney disease.
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Adult↗
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↗
[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↗