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Biomedical subjects

H Pralle

Publications and source records attributed to H Pralle.

103 records · Page 6Linked to original sources
PubMed1975

New kind of cytoplasmic inclusions of plasma cells in acid maltase deficiency.

Extensive 'vacuolization' could be demonstrated in nearly all plasma cells and in some lymphocytes of an adult with glycogenosis type II (Pompe's disease). The biochemically defined diagnosis acid maltase deficiency (AMD) could be ascertained by examination of the maltase activity of the patient's leukocytes. Electron microscopical, microspectrographic, and cytochemical investigations revealed electron dense inclusions, which show an UV absorption at 276 nm and a positive reaction after PAS staining of plastic embedded material. Since no other abnormalities of the plasma cells could be found, our results are presumably indicative for a connection of AMD and a glycoprotein storage in the plasma cells of the patient.

Adult↗
PubMedDate not supplied

The influence of the protease inhibitor aprotinin on tumor invasion of three cell lines in vitro.

The production of protease by malignant cells has been held responsible for invasion. The effect of aprotinin, a broad-spectrum protease inhibitor, on malignant invasion was examined histologically in organotypical cocultures of precultured embryonic chick heart fragments with two human melanoma cell lines and one virus-transformed fetal mouse carcass cell line. In the presence of 400 KIU/ml aprotinin, invasion was still permissive, while in the comparison with 0.1 microgram/ml vincristine, a microtubule and directional motility inhibitor and a well-documented anti-invasive agent, invasion was completely stopped. Aprotinin remained stable in the culture medium so that the presence of invasion cannot be explained by low drug concentration. It is concluded that aprotinin-sensitive proteases are not implicated in invasion in vitro in the cell types investigated, and that this in vitro technique deserves further interest for the study of protease inhibitors in the mechanism of invasion.

Animals↗
PubMedDate not supplied

Reactivity of platelets from healthy individuals and from patients with hematologic diseases following incubation with pegylated recombinant human megakaryocyte growth and development factor in vitro.

Platelets express the receptor for thrombopoietin. It is possible that thrombopoietin modulates platelet reactivity. We examined the effect of pegylated recombinant human megakaryocyte growth and development factor (PEG-rHuMGDF) on platelet activation in vitro using flow cytometry. We compared samples from healthy individuals and from patients with various hematologic diseases (AML, myeloma, postchemotherapy). Citrated whole blood was incubated with PEG-rHuMGDF (10 or 100 ng/ml), then a mild stimulus was added (0.1 U thrombin/ml). Blood from healthy individuals showed a significantly higher degree of platelet activation (CD62p expression), microparticle generation, and aggregate formation after incubation with PEG-rHuMGDF+thrombin versus thrombin alone (p < 0.05). However, this difference could not be shown for platelets from patients with thrombocytopenia or other hematologic diseases. The use of PEG-rHuMGDF should be safe and not cause an additional risk of thromboocclusive disease in these patients.

Adult↗
PubMedDate not supplied

Relative and absolute changes of activated platelets, microparticles and platelet aggregates after activation in vitro.

Standard flow cytometers provide relative numbers of activated platelets, microparticles, and platelet aggregates. With fluorescent beads it is now possible to determine absolute numbers. Whole blood and platelet-rich plasma were incubated with agonists (ADP, collagen, thrombin). CD62p expression, microparticle and platelet aggregate formation were measured. Flow-Count Fluorospheres((R)) were added to calculate absolute concentrations. After activation there was an increase in the percentage of CD62p-positive platelets. However, the total number of platelets decreased and therefore the absolute number of CD62p-positive platelets did not increase but decreased. The number of CD62p-positive platelets decreased not as much as the number of CD62p-negative platelets, which explains why the relative percentage of CD62p-positive platelets increased. A similar increase in percent and decrease in absolute counts was found for microparticles. Platelet aggregates increased both in relative and absolute numbers. These results suggest that the detection of activated platelets by flow cytometry has to be complemented by the determination of the absolute concentrations to avoid misinterpretation.

Blood Platelets↗
PubMedDate not supplied

Comparison of beta-thromboglobulin, flow cytometry, and platelet aggregometry to study platelet activation.

This study compares granule membrane protein (GMP)-140 expression measured by flow cytometry, release of beta-thromboglobulin (beta-TG), and platelet aggregometry as markers of platelet activation in vitro. Whole blood was activated with different concentrations of thrombin. There was a significant increase in beta-TG plasma levels after stimulation with 0.01 and 0.04 U thrombin/ml. There was also an increase in GMP-140 expression, but interindividual variability was high. Aggregometry of platelet-rich plasma did not detect platelet activation and formation of platelet aggregates with 0.05 and 0.1 U thrombin/ml, while flow cytometry showed an early and significant increase of GMP-140 expression with these doses. Beta-TG release is a more sensitive marker of platelet activation than GMP-140 while flow cytometry is easier to perform and less susceptible to artifacts.

Anticoagulants↗