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Biomedical subjects

M Kalinowski

Publications and source records attributed to M Kalinowski.

At least 37 records · Page 2Linked to original sources
PubMed1998

[Plaque morphology after arterial interventions in the New Zealand white rabbit--which model of restenosis is most suitable?].

PURPOSE: For evaluation of therapy for possible reduction of restenosis after PTA a suitable animal model is needed. The influence of different interventions on arterial plaque composition was analysed in New Zealand White Rabbits. MATERIAL AND METHODS: The following interventions were performed in the infrarenal aorta of New Zealand White Rabbits (n = 42): a) Balloon denudation (BD) with and b) without 0.5% cholesterol diet (CD), c) application of a Wiktor stent, d) CF without BD, and e) control group, 6 weeks after intervention morphometry and histology were performed. RESULTS: After BD the stenosis rate measured 26 +/- 18%, additional CD after prior BD increased the stenoses rate by 2.5 times up to 61.1%. After stent implantation there was only a thin neointimal layer (89 +/- 68 microns) around the stent wires. CONCLUSIONS: Neither implantation of stents nor single CD are suitable as restenosis models. BD with and without CD was followed by a distinct neointima formation with different cellular composition. The New Zealand White Rabbit constitutes an acceptable model for contemporary research in arteriosclerosis.

Angioplasty, Balloon↗
PubMed1998

[Intra-arterial application of the ACE inhibitor ramipril using a microperforated catheter for the prevention of neointimal proliferation after angioplasty in an animal model].

PURPOSE: To evaluate the safety and benefit of a high-dose local drug administration via a microporous balloon catheter to prevent neointimal formation after balloon angioplasty. MATERIALS AND METHODS: In New Zealand white rabbits (n = 29) neointima formation was induced by balloon denudation. Additionally, the animals were fed a 0.5% cholesterol diet for 6 weeks. Directly after the denudation, local application of 1.8 mg ramipril (n = 7) or saline (n = 7) via a microporous balloon catheter was performed. Other animals (n = 7) were treated with a systemic ramipril administration. One control group were exclusively fed with a cholesterol diet (n = 8). 6 weeks after intervention the animals were sacrificed and morphometry of the vessels was performed. RESULTS: Local administration of ramipril resulted in a non-significant reduction of 17%. The local administration mode was combined with a significant increase in neointima formation. Systemic ramipril administration resulted in a 66% reduction of plaque area. CONCLUSIONS: The benefit of the local ramipril administration was diminished by the inherent vessel trauma. Systemic ramipril administration resulted in a significant reduction of neointimal proliferation in New Zealand white rabbits.

Angioplasty, Balloon↗
PubMed1997

[Use of low-molecular weight heparin during hemodialysis].

Coagulation parameters--platelet aggregation, beta-thromboglobulin, fibrinopeptide A were analyzes in patients with final chronic renal insufficiency during haemodialysis after a low molecular weight heparin application. In the study was documented that standard heparin is able to induce platelet aggregation. A low molecular weight heparin is suggested as sefex, because no influence on platelet aggregation was determined.

Adult↗
PubMed1996

Inverse relationships between haemoglobin and ristocetin-induced platelet aggregation in haemodialysis patients under erythropoietin therapy.

BACKGROUND: Amelioration of the anaemia of chronic renal failure and subsequent improved haemorheology result in correction of bleeding diathesis as evidenced by shortening of the skin bleeding time (BT). However, the relationship between the haematocrit and platelet-vessel wall interactions in haemodialysis (HD) patients under recombinant human erythropoietin (rHuEpo) therapy, assessed by platelet aggregation in response to ristocetin is more complex and somewhat inconsistent. METHODS: We investigated the relationship between haemoglobin (Hb) levels and whole blood ristocetin-induced platelet aggregation (electric impedance method) in 28 HD patients treated with rHuEpo, and with normal BT. The measurements were repeated in 16 subjects after having reduced platelet aggregability with orally administered ketanserin. RESULTS: Ristocetin-induced platelet aggregation in the whole group was comparable to those found in 21 age-matched healthy subjects (normals) and in 25 HD patients not treated with rHuEpo (uraemics). Interestingly, a significant inverse correlation between this aggregation and Hb concentration was found (r = -0.392, P < 0.05). In the group of 16 patients, the pre-ketanserin aggregation was more intensive than in the normals and uraemics (P < 0.05). Ketanserin produced a fall in ristocetin-induced platelet aggregation (P < 0.02), prolongation of the BT (P < 0.02) and, unexpectedly, a decrease in serum Epo concentration (P < 0.0002) and the Hb level (P < 0.001). Again, an inverse correlation between depressed ristocetin-induced platelet aggregation and lowered Hb concentration was found (r = -0.590, P < 0.02). Moreover, a strong positive correlation between the extent of preketanserin platelet aggregation and the decrease in the intensity of this process that followed the trial was observed (r = 0.919, P < 0.000005). There were no changes in other haematological parameters or arterial blood pressure. CONCLUSIONS: Considering the role of von Willebrand factor and fibrinogen in mediating ristocetin-induced platelet aggregation, and enhanced synthesis and/or release of these macromolecules in response to uraemia or inflammation, we suggest that exaggerated whole-blood platelet aggregability to ristocetin points to blunted erythropoiesis in HD patients on rHuEpo therapy.

Adult↗
PubMed1996

[Effect of deferoxamine on erythropoiesis in patients hemodialyzed for chronic renal insufficiency treated with erythropoietin].

The aim of the study was to evaluate the effect of deferoxamine therapy on erythropoiesis, aluminium concentration and iron metabolism in hemodialyzed patients with chronic renal insufficiency treated with human recombinant erythropoietin (Eprex, Cilag). 8 hemodialyzed patients (2 female and 6 male) in long-term programme with aluminium serum concentration over 160 micrograms/l were treated with deferoxamine (5 mg/kg b.m.) during the last hour of hemodialysis in slowly intravenous infusion since 1 months. During this treatment aluminium and iron serum concentrations, serum iron-binding capacity, transferrin and hematocrit were determined before and after 1 months of deferoxamine therapy. The significant decrease of aluminium serum concentration (p < 0.05) and increase of hematocrit (p < 0.01), iron (p < 0.05) and serum iron-binding capacity (p < 0.001) were determined. The results of performed analysis indicate that aluminium is able to inhibit erythropoiesis induced by erythropoietin. The improvement in erythropoiesis and iron metabolism after deferoxamine therapy was observed.

Adult↗
PubMed1995

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↗
PubMed1995

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↗
PubMed1994

Clot-embedded natural surfactant: kinetics of fibrinolysis and surface activity.

Polymerization of fibrin in the presence of pulmonary surfactant was recently noted to induce incorporation of phospholipids into the insoluble clot material, thereby effecting severe loss of surface activity (W. Seeger, A. Elssner, A. Günther, H.-J. Krämer, and H. O. Kalinowski. Am. J. Respir. Cell Mol. Biol. 9: 213-220, 1993). In the present study, we investigated the influence of such incorporation of calf lung surfactant extract (CLSE) on the enzymatic cleavage of the fibrin network with the use of plasmin, trypsin, or elastase. Employing a fibrin-plate assay, the proteolytic release of radioactivity originating from 125I-labeled fibrinogen was assessed, and the pattern of split products was characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis technique. Surface activity of CLSE was measured in the pulsating bubble surfactometer. When incorporated into the fibrin clot, CLSE inhibited the cleavage of fibrin by all proteases in a dose-dependent manner without affecting the profile of scission products. Inhibition of plasmin-induced clot lysis was also noted on incorporation of CLSE into clotted plasma and on incorporation of dipalmitoylphosphatidylcholine into fibrin polymers. In contrast, corresponding concentrations of CLSE added to the incubation medium after preformation of the fibrin matrix did not substantially influence the kinetics of fibrinolysis. CLSE incorporation into the nascent fibrin clot resulted in complete loss of surface activity, but adsorption and surface tension-lowering properties were largely restored by subsequent plasmic clot lysis. Arising fibrin split products were shown to display similar inhibitory strength on CLSE surface activity compared with fibrinogen split products.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

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↗
PubMed1983

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↗
PubMed1977

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↗