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Biomedical subjects

M Kalinowski

Publications and source records attributed to M Kalinowski.

At least 19 recordsLinked to original sources

A study of platelet functions, some hemostatic and fibrinolytic parameters in relation to serotonin in hemodialyzed patients under erythropoietin therapy.

Erythropoietin corrects anemia and improves hemostasis, but on the other hand bears a risk of thrombotic complications. Therefore in the present study an attempt has been made to evaluate bleeding time, platelet functions and some hemostatic and fibrinolytic parameters in relation to blood and platelet serotonin before and after 1, 2, 4, 8 and 12 weeks of treatment. 22 chronically hemodialyzed patients were administered with human recombinant erythropoietin (rHuEPO) in a dose of 2000 IU s.c. 3 times a week. Bleeding time was shortened significantly as early as after 1 week of the therapy, whereas hematocrit and hemoglobin increased after 2 weeks. These changes lasted throughout the study. Only a transient rise in platelet count, collagen-induced platelet aggregation, beta-thromboglobulin and VIII:C activity were observed during therapy relative to baseline values. ADP- and arachidonic acid-induced platelet aggregation seemed to be unaffected by rHuEPO treatment, whereas a gradual and progressive enhancement in platelet aggregation in response to ristocetin was found, starting from the 2nd week of the therapy. It lasted throughout the study and correlated inversely with the bleeding time and positively with a rise in both blood and platelet serotonin. rHuEPO did not alter plasminogen, fibrinogen, platelet factor 4, alpha 2 macroglobulin levels, protein C activity and euglobulin clot lysis time. A decline in protein C and S concentrations and antithrombin III activity observed during the therapy were counterbalanced by a fall in the activity of alpha 2 antiplasmin, C1 esterase inhibitor and plasminogen activator inhibitor. It is concluded that rHuEPO may improve platelet/vessel wall interactions possibly by means of serotonergic mechanisms. A lowered activity of inhibitors of fibrinolysis may be regarded as a protection against a general tendency to thrombosis during rHuEPO therapy.

Adenosine Diphosphate

Surfactant incorporation markedly alters mechanical properties of a fibrin clot.

Intra-alveolar clot formation is a common finding in acute and chronic inflammatory lung diseases. Incorporation of lipophilic surfactant components into a growing fibrin clot has recently been reported (Am. J. Respir. Cell Mol. Biol. 1993; 9:213-220). In the present study, we investigated the influence of such surfactant incorporation on the elastic properties and water permeability of the fibrin polymer. Thrombelastography and compaction experiments were employed for assessment of the elastic properties, and the permeability characteristics of the clot material were addressed in fibrin-packed columns. Two calf lung surfactant extracts (CLSE and Alveofact), Curosurf, and a synthetic phospholipid mixture (dipalmitoylphosphatidylcholine, phosphatidylglycerol, and palmitic acid at a ratio of 68.5:22.5:9 [wt/wt]) were used. The presence of surfactant did not affect the cleavage of fibrinopeptide A upon incubation of fibrinogen with thrombin (enzyme-linked immunosorbent assay technique). Similarly, kinetics and extent of factor XIII-induced covalent crosslinkage of the fibrin network remained unchanged in the presence of surfactant (sodium dodecyl sulfate polyacrylamide gel electrophoresis and D-Dimer quantification upon subsequent clot lysis). All surfactants, however, dose-dependently decreased the elastic modulus of the arising fibrin polymer. The maximal amplitude in thrombelastography was reduced, and the recovery of fluid after centrifugation of the fibrin clot increased. Fibrin clots embedding natural surfactant material displayed reduced permeability for saline as compared with control fibrin polymers. Subsequent washout of lipids from these clots with Triton X-100 resulted in increased hydraulic conductivity. This was accompanied by an increase in pore size, suggesting altered architecture of the fibrin matrix generated in the presence of surfactant.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals

Dietary selenium intake of preschool children.

The results of this investigation indicate that the range of selenium intakes of the preschool children who were studied was in the acceptable range of adequate and safe as suggested by the Food and Nutrition Board. The majority of the selenium in the diets of the subjects came from grains. Although the amount of selenium consumed was within normal limits, the concentration in the diet was estimated to be 70% of the expected value for mixed diets, i.e., 0.1 microgram/gm.

Child, Preschool

Concentration and subcellular localization of zinc in the hippocampal formation, cerebellum, and whole brain during the postnatal development of the rat.

Zinc was determined by means of atomic absorption techniques in the hippocampal formation, the cerebellum, the whole brain, and their subcellular fractions during the postnatal development of rats. Large quantities of zinc were found already in newborn animals. In the whole brain, the zinc amounts increased between the birth and the 15th day of age, whereas in the hippocampal formation and cerebellum the zinc concentration did not change remarkably during the postnatal maturation. The zinc content of the subcellular fractions revealed a shift to the synaptosomes and mitochondria during the postnatal development. No significant difference of zinc amounts was shown between the CA3 and hilus fasciae dentatae region and the whole hippocampal formation. Concluding from the present results there are obvious discrepancies between the quantitative and histochemical data of the zinc distribution in the rat brain.

Aging

Conductance of the cytoplasm of erythrocytes as a criterion for evaluating the quality of blood preservation.

It has been established that enzymic systems become exhausted during the preservation of blood, which causes disturbances in the transport of ions across the cell membrane. These changes occurring in the cell may be recorded by measuring the electrical conductance of cytoplasm. The conductance has been determined for three selected preserving liquids in relation to the blood storage time. Results of this study showed that the dynamics of changes in the electrical conductance of the cytoplasm is characteristic for a given type of the preserving liquid. Hence, the determination of changes in the electrical conductance of the cytoplasm may provide a new important criterion for evaluating various methods of blood preservation.

Blood Preservation