Transcription factors Fli1 and EKLF in the differentiation of megakaryocytic and erythroid progenitor in 5q- syndrome and in Diamond-Blackfan anemia.

Friend leukemia virus integration 1 (Fli1) and erythroid Krüppel-like factor (EKLF) participate under experimental conditions in the differentiation of megakaryocytic and erythroid progenitor in cooperation with other transcription factors, cytokines, cytokine receptors, and microRNAs. Defective erythropoiesis with refractory anemia and effective megakaryopoiesis with normal or increased platelet count is typical for 5q- syndrome. We decided to evaluate the roles of EKLF and Fli1 in the pathogenesis of this syndrome and of another ribosomopathy, Diamond-Blackfan anemia (DBA). Fli1 and EKLF mRNA levels were examined in mononuclear blood and bone marrow cells from patients with 5q- syndrome, low-risk MDS patients with normal chromosome 5, DBA patients, and healthy controls. In 5q- syndrome, high Fli1 mRNA levels in the blood and bone marrow mononuclear cells were found. In DBA, Fli1 expression did not differ from the controls. EKLF mRNA level was significantly decreased in the blood and bone marrow of 5q- syndrome and in all DBA patients. We propose that the elevated Fli1 in 5q- syndrome protects megakaryocytic cells from ribosomal stress contrary to erythroid cells and contributes to effective though dysplastic megakaryopoiesis.

Bird schistosomes in planorbid snails in the Czech Republic.

Bird schistosomes have been in focus as causative agents of cercarial dermatitis of humans in the last years; however, our knowledge of their species spectrum and intermediate host specificity is still insufficient. Our study focused on bird schistosomes developing in planorbid snails that have been less studied so far. From 2001 to 2010, cercariae of bird schistosomes were found in four snail species (Gyraulus albus, Segmentina nitida, Anisus vortex and Planorbis planorbis) from seven localities in the Czech Republic. Based on morphology and results of molecular analysis, the isolates found belong to at least six species. Five of them are probably undescribed species, and one species appears to be identical with Gigantobilharzia vittensis Reimer, 1963 (syn. G. suebica Dönges, 1964). The finding from S. nitida represents the first report of a bird schistosome from this snail.

[Cell death and its role in immunopathogenesis of infectious diseases]. / Bunecna smrt a jeji role v imunopatogenezi infekcnich chorob.

Cell death is still a matter of debate and scientific opinions have been challenged and are not uniform due to complexity of this issue. Recent research has brought some new evidence about the very subtle border between programmed cell death and necrosis. The concept of their mutual independence, broadly accepted for decades, is now significantly challenged. Lack of unified terminology led to the establishment of the Nomenclature Committee on Cell Death (NCCD) which provides recommendations for clear definition of distinct cell death programs. It also appeals for consistent application of this nomenclature in scientific literature. In this work, some keystone knowledge addressing three specific programmed cell death types - apoptosis, autophagic cell death, and pyroptosis which is recognized as a controversial cell death scenario on the border between programmed cell death and necrosis, is reviewed. These cell death scenarios are discussed in the context of pathogenesis of infectious diseases.

Up-regulation of the Apo/Fas (CD95) complex on neutrophils harvested during cardiac surgery: distinct findings in patients operated on with or without the use of cardiopulmonary bypass.

AIMS: In a group of patients undergoing cardiac surgery performed both with ("on-pump") and without the use ("offpump") of cardiopulmonary bypass (CPB), we studied the changes of neutrophil membrane apoptosis-inducing complex Apo/Fas. METHODS: Expression of Apo/Fas (CD95) on leukocytes was evaluated by flow cytometry. RESULTS: In "on-pump" patients, we found an increase in the expression of CD95 median intensity fluorescence (MFI) on granulocytes from a baseline level median=56, (Q( 1)=45.5, Q(3)=64) to a median=88, (Q(1)=62, Q( 3)=109.5; p<0.01) at the 3(rd) postoperative day and median=74, (Q(1)=63, Q(3)=84.5; p<0.01) at the 7(th) postoperative day. In "off-pump" patients, granulocyte CD95 MFI was median=55, (Q(1)=51, Q(3)=84) before surgery. The significant increase was found on the 3(rd) postoperative day only; median=90, (Q( 1)=66; Q(3)=98; p<0.05). A similar pattern in the CD95 expression was also found if percentage changes of granulocyte CD95 MFI were followed. Moreover, the significantly increased Apo/Fas expression expressed as a percentage change of CD95 MFI was found in "on-pump" patients compared to "off-pump" patients, both at the 3(rd) postoperative day (p<0.05) and at the 7(th) postoperative day (p<0.01). CONCLUSIONS: This is the first direct evidence of increasing densities of the Apo/Fas complex on neutrophils in cardiac surgical patients.

[Principles of macrophage resistance to intracellular parasites]. / Principy rezistence makrofagu vuci intracelularnim parazitum.

Intracellular parasitism is a phenomenon present in nature for more than one billion years. Its keystone is the intriguing ability of viruses and some bacteria to survive and multiply inside eukaryotic host cells and to parasitize on their metabolic machinery. According to the classical definition, germs are classified as intracellular parasites only if they are able to survive inside macrophages. However, the ability of germs to survive inside eukaryotic cells is much more common than it was expected earlier. Reaction of macrophages to invading microbes is the key point in the complex immunological resistance of the host. The outcome of the host is substantially linked to macrophage reactivity. For example, if an evading microbe with a replication time of 20 minutes survived inside a host for 24 hours without reaction of innate immunity, there would be more than 2 x 1021 microbes at the end of this period. It would be fatal for the host, indeed. The key activities of macrophages in the sense of protection against intracellular parasites are reviewed. Some mechanisms of microbial defence and some new approaches to clinical diagnosis of the functional status of cells of innate immunity are also discussed.

The effect of interferon-gamma and lipopolysaccharide on the growth of Francisella tularensis LVS in murine macrophage-like cell line J774.

BACKGROUND: Francisella tularensis, a causative agent of human tularemia, displaying the ability to proliferate inside the human cells. AIMS: To evaluate the growth potential of F. tularensis LVS strain in macrophage-like cell line J774 modulated by recombinant interferon gamma and E. coli derived lipopolysaccharide. RESULTS: Stimulation of J774 cells either by interferon-gamma or lipopolysaccharide alone, or especially in combination before infection F. tularensis, revealed protective effects. Higher concentrations of stimulating agents were needed to inhibit ongoing F. tularensis infection. CONCLUSIONS: Stimulation of J774 cell line by combination of interferon-gamma with lipopolysaccharide inhibits the intracellular growth of F. tularensis.