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Biomedical subjects

M Böck

Publications and source records attributed to M Böck.

At least 37 records · Page 2Linked to original sources

[Thrombocyte transfusion. Indications, side effects and problems].

The transfusion of platelet concentrates now represents one of the most common therapeutic measures employed in transfusion medicine. In particular the development of new, aggressive forms of chemotherapy has rapidly increased the need for platelet concentrates over the last few years. The aim of the present study is to describe the major indications and discuss briefly the side effects and problems associated with the transfusion of platelet concentrates.

Blood Group Incompatibility↗

Storage of single-donor platelet concentrates: metabolic and functional changes.

During the last decade, the trend toward intensifying chemotherapeutic regimens in patients with hematologic malignancies rapidly increased the demand for single-donor platelet concentrates (PCs). The logistics of such supply, however, necessitated the storage of these blood components prior to transfusion. Today, most blood centers use di(2-ethylhexyl)phthalate-free blood bags, which are assumed to allow a storage period of up to 5 days. This report describes biochemical and functional changes of stored single-donor PCs, which may influence the expected quality of PCs. The acid-base status is characterized by an initial respiratory alkalosis compensated by a metabolic acidosis. Changes in extracellular electrolyte, lactate dehydrogenase, glucose, lactate, elastase, and complement levels, as well as in the release of alpha granule content and the initial activation of plasma coagulation, are demonstrated. These changes result in a functional impairment of stored PCs as reflected by thromboxane and serotonin release reaction and by aggregation and in vitro bleeding time studies. In contrast, in vivo recovery and survival rates have been reported to be unaffected. Whether the good recovery and survival rates are caused by a rejuvenescence of stored PCs in vivo or are due to injured circulating platelets has not yet been proven.

Adenosine Diphosphate↗

[Substitution of thrombocyte concentrates in polytransfused patients].

The routine use of platelet concentrates has greatly increased during the last years. Most of the concentrates are transfused to hematologic patients, who frequently receive additional red blood cells. These polytransfusion regimens often result in the formation of HLA- or platelet-specific antibodies, which lead to refractoriness to further platelet support. In order to avoid this problem, the number of HLA antigens transmitted should be reduced. Therefore, a consequent leukocyte depletion of all blood products administered to multitransfused patients seems to be necessary. If antibodies are already preformed in the patient's serum, compatible platelets have to be selected for transfusion.

Animals↗

[Storage of thrombocyte concentrates: quality control by in vitro bleeding test].

BACKGROUND: The increasing demand for single-donor platelet concentrates necessitates the storage of these blood products prior to transfusion. Quality control of these platelets, however, is still a problem. Most of the available techniques are time-consuming and require sophisticated equipment and specifically trained personnel. The present paper describes a new method for quality control of stored platelet concentrates. MATERIALS AND METHODS: Single-donor platelet concentrates were stored for 7 days; daily aliquots were taken and the in vitro bleeding time (Thrombostat 4000) and platelet aggregation (aggregometer) were determined. RESULTS: The in vitro bleeding test can be handled simply and fast. The results are comparable with those of platelet aggregation tests. CONCLUSION: The in vitro bleeding test provides a good alternative to the conventional methods commonly used for quality control of platelet concentrates.

Bleeding Time↗

Intravenous anti-D gammaglobulin for the prevention of rhesus isoimmunization caused by platelet transfusions in patients with malignant diseases.

Previous studies of sensitization to RhD by RhD-positive platelet transfusions in RhD-negative cancer patients have shown different frequencies of alloimmunization (max. 19%). We studied 37 RhD-negative patients who received RhD-incompatible platelet transfusions and simultaneously anti-D-immune globulin. We provide evidence that in this setting RhD-prophylaxis is highly effective in preventing alloimmunization due to RhD antigen, since none of the patients studied developed anti-D. Detection of other red blood cell antibodies than anti-D proves the possibility of immunization in these patients. Prevention of isoimmunization in patients with malignant diseases is recommended especially in young females, since an increasing number of patients are having successful pregnancies, despite prior or even during cytotoxic therapy.

Adult↗

[Graft versus host disease with fatal outcome after administration of filtered erythrocyte concentrates].

Transfusion-associated graft-versus-host disease (TA-GVHD) resulting from the engraftment of competent lymphocytes contained in blood products has been well described in immunocompromised patients and more recently in immunocompetent patients. Prophylactic irradiation of blood products prior to transfusion is the most efficient way to prevent TA-GVHD. Standard blood bank measures to reduce mononuclear cell contamination in red blood cell units, such as freezing, washing and filtration, may reduce the number of viable lymphocytes to prevent immunizations. However, it is unknown whether the depletion of leukocytes with these techniques would decrease the risk of TA-GVHD. In this report we describe the first case of TA-GVHD following transfusion of filtrated red blood cells given to a patient receiving cytotoxic therapy for Hodgkin's disease.

Adult↗

[Combination of a simple hollow fiber system with leukocyte filter for production of leukocyte depleted erythrocyte concentrates and plasma].

Leukocyte-depleted red cell concentrate (RCC) and plasma were separated by a hollow fiber filter system combined with a leukocyte filter without any additional devices. The RCC with 100 ml additive solution had a weight of 329 g; hematocrit was 0.55, free hemoglobin 16 mg/dl; leukocytes were (0.6 +/- 0.6) x 10(9)/l. The plasma (268 g) contained 5.4 g/dl of total protein, and only a few blood cells; clotting factor VIII activity 75%, all satisfying the guidelines.

Blood Component Removal↗

[Incidence of the detection of erythrocyte antibodies in relation to screening test cells].

A variety of antibody screening tests are available to detect immunization in patients' sera. However, antibodies can be observed only if corresponding antigens are present on test cells used by an antibody screen. By comparing available test cell kits of different manufacturers we revealed various specificities of antigens present or absent on these cells. Using by an antibody screen Wr(a+), Co(b+) and Kp(a+) test cells additionally to available test cells, we detected in 1000 sera of patients 13 anti-Wr(a) and 1 anti-Co(b) besides 17 antibodies with different specificities.

Autoantibodies↗

Acetylsalicylic acid and blood coagulation in the horse.

Equine blood may contain salicylic acid (SA) taken up as free acid or represents the metabolite of acetylsalicylic acid (ASA). To obtain information of SA in race horses we screened blood samples of trotting-horses routinely drawn to be analyzed for doping substances. The individual values determined followed a Gaussian distribution displaying a geometric mean of 19 ng SA per ml serum. A probit analysis revealed linear relationship (r = 0.995). Additional studies examined the antithrombotic efficacy of ASA in the horse. An oral dose of 300 mg ASA considerably elevated the bleeding time for more than 2 hours with concomitant SA serum levels between 800 and 1000 ng/ml. It is concluded that salicylate levels even below 1 microgram/ml serum bring about considerable pharmacologic effects such as prolongation of bleeding time, decrease in blood viscosity and possibly dilatation of blood vessels. These effects may improve the tissue supply with blood including oxygen.

Animals↗

White cell depletion of single-donor platelet preparations by a new adsorption filter.

A newly developed adsorption filter has been evaluated for the removal of white cells (WBCs) from platelet concentrates. It consists of surface-modified polyester fibers and can be used at the patient's bedside. WBC mean removal rate was 98.8 +/- 0.9 percent, and platelet recovery was 99.0 +/- 0.7 percent. The aggregation curves (ADP, collagen) and hypotonic shock response of platelets were not influenced by the filtration, and the plasma electrolyte and lactate dehydrogenase concentrations were unaffected. Transmission and scanning electron micrographs showed no difference in platelet ultrastructure before and after filtration. Determination of posttransfusion platelet recovery did not reveal any significant difference from that of nonfiltered platelets. The tested filter seems to be a suitable device for WBC depletion of single-donor platelet concentrates at the bedside.

Adenosine Diphosphate↗

Presence of T-antigen on the vascular endothelium.

Bacterial neuraminidase plays an important role in the pathogenesis of some haemolytic anaemias. It divides neuraminic acid from the red cell surface to expose a hidden antigen (Thomsen-Friedenreich antigen, T). A physiologically circulating antibody can then react with the uncovered T and cause a rapid haemolysis. This study demonstrates the presence of T on human vascular endothelium. Similar to red cells it is exposed by the action of bacterial neuraminidase. The subsequent reaction with the physiological antibody could be involved in the pathogenesis of vascular damage observed in severe cases of bacterial septicaemia.

Animals↗

[Storage of thrombocyte concentrates: ultrastructural and functional changes].

Optimal storage of platelet concentrates is still an unsolved problem. The present paper demonstrates changes in morphology and function of stored platelets. Transmission microscopy reveals a loss of organelles as well as a progredient destruction of cell membranes during storage. At the same time in vitro aggregability is clearly diminished. Therefore, further investigations seem to be necessary to improve storage conditions of platelets.

Blood Component Transfusion↗

[Preparation of leukocyte-depleted thrombocyte concentrate: in-vitro testing of a new filtration system (PL 100)].

A newly developed filter-system (PL 100) for the removal of leukocytes from platelet concentrates was tested. It removes contaminating leukocytes by 99.7 +/- 0.6%. The platelet loss was calculated as 25.7 +/- 9.5%. The filtration process does not influence the filtered platelets; plasma-electrolytes, LDH-concentrations, platelet aggregation curves and serotonin-release remain constant. In addition, platelet ultrastructure is not influenced by the filtration. In spite of the high platelet loss, the tested filter-system seems to be a suitable alternative to the conventional methods for the removal of contaminating leukocytes from platelet concentrates.

Blood Platelets↗

Preparation of white cell-depleted blood. Comparison of two bedside filter systems.

Numerous techniques have been established for preparing white cell-poor blood, such as centrifugation, sedimentation, freezing, and filtration. All of these methods have disadvantages that restrict their practical use: they are time-consuming, they require the facilities of a blood bank, and the white cell-poor units cannot be stored. Therefore tests have been performed on two filter systems that make possible the depletion of white cells directly at the bedside. Both filters have a high white cell-removal rate. The number of residual white cells in 1 unit of packed red cells was calculated as 1.08 +/- 0.53 x 10(7) in one system and 1.54 +/- 0.71 x 10(7) in the other. The filters do not affect the filtered red cells. Pressure filtration is performed without significant loss of efficiency. One of the systems can filter 2 units via one filter; however, handling the filters is tedious, and both filters are characterized by a low red cell recovery. Despite these disadvantages, the tested filter systems provide an effective device for preparing white cell-poor blood at the bedside. They are a suitable alternative to the conventional methods.

Blood Platelets↗

[Production of leukocyte-poor thrombocyte concentrates: results with a new kind of filter system].

A newly developed filter-system (Sepacell PL) for the removal of leukocytes from single donor platelet concentrates was tested. It removes contaminating leukocytes by 99.9%, the platelet loss was calculated as less than 1%. Platelet ultrastructure and function do not seem to be altered by the filtration. Therefore, the tested filter system seems to be a suitable device for leukocyte depletion of single donor platelet concentrates. Further clinical studies, however, are necessary to prove the efficiency of the filter system in preventing alloimmunization in vivo.

Blood Transfusion↗