Generation of functional dendritic cells for potential use in the treatment of acute lymphoblastic leukemia

Immunotherapy of malignant diseases mediated by dendritic cells (DC) pulsed with tumor antigens ex vivo is a promising new tool in the individual treatment of malignant diseases. The present study focuses on the problem of how to optimize in vitro culture conditions and induce the maturation of DC with the capacity to induce antitumor immunity toward leukemic cells. DC were generated from peripheral mononuclear cells by co-cultivation with granulocyte/macrophage-colony stimulating factor (GM-CSF) and interleukin-4 (IL-4). Tumor antigens were added for 2 h after 7 days in culture. Irradiated leukemic blasts, blast lysate, apoptotic cells from the Jurkat cell line (T ALL) and their lysate were used in various concentrations for antigen pulsing. Harvested DC were phenotyped by flow cytometry, and viability was assessed using trypan blue exclusion (Annexin test). After the cells had been pulsed with tumor antigens and co-cultured with autologous lymphocytes, the production of interferon-gamma (IFN-gamma) and IL-12 was analyzed, and lymphocyte proliferative response and cytotoxicity against the target tumor cell line were assessed. The cultivation of monocytes under the described conditions led to the expression of surface markers typical of DC (i.e. CD83, CD86, HLA-DR, CD11c and CD40). Pulsation by antigens from leukemic cells further increased the cell populations expressing these markers. Antigen pulsation decreased the viability of generated DC depending on the increase in concentration of tumor antigens. Pulsed DC-lymphocyte interaction increased the proliferative response of lymphocytes and IFN-gamma production depending on the type of tumor antigens used for pulsation. The highest proliferative response was detected with DC pulsed with Jurkat cell-line lysate. Similarly to the proliferation assay, cytotoxic testing showed the highest efficiency of DC pulsed with Jurkat cell-line lysate in killing the target malignant cells. Our results show that an appropriate antigen concentration used for DC pulsing is one of the crucial factors in an effective treatment strategy, as high concentrations of tumor antigens induce apoptosis of DC, thereby rendering them non-functional. Under optimal conditions, pulsation by lysate from leukemic blasts induced the maturation of DC and led to an increase in the proliferation of autologous lymphocytes, to the production of Th1-cytokines and to the induction of cytotoxicity toward the leukemic cell line. These results are encouraging for the possible application of pulsed DC in the therapy of acute lymphoblastic leukemia.     

Eye Movements in Ephedrone-Induced Parkinsonism

Patients with ephedrone parkinsonism (EP) show a complex, rapidly progressive, irreversible, and levodopa non-responsive parkinsonian and dystonic syndrome due to manganese intoxication. Eye movements may help to differentiate parkinsonian syndromes providing insights into which brain networks are affected in the underlying disease, but they have never been systematically studied in EP. Horizontal and vertical eye movements were recorded in 28 EP and compared to 21 Parkinson''s disease (PD) patients, and 27 age- and gender-matched healthy subjects using standardized oculomotor tasks with infrared videooculography. EP patients showed slow and hypometric horizontal saccades, an increased occurrence of square wave jerks, long latencies of vertical antisaccades, a high error rate in the horizontal antisaccade task, and made more errors than controls when pro- and antisaccades were mixed. Based on oculomotor performance, a direct differentiation between EP and PD was possible only by the velocity of horizontal saccades. All remaining metrics were similar between both patient groups. EP patients present extensive oculomotor disturbances probably due to manganese-induced damage to the basal ganglia, reflecting their role in oculomotor system.     

Ragweed in the Czech Republic

During the last years, a well documented expansion ofragweed (Ambrosia artemisiifolia L., Ambrosia trifida L.) over the Mediterranean andtemperate Europe has been in progress. The currentdistribution of ragweed plants in the Czech Republicis summarized and the ragweed pollen concentration asmonitored by 12 pollen stations in the country isdiscussed. The present situation in the ragweed pollensensitization among children and adults with pollenallergy in Brno is described. So far no dangerousexpansion of ragweed plants in our country has beenobserved. Ragweed pollen concentration is occasionallysignificant in the Brno station only, other pollenstations are reporting insignificant amounts ofragweed pollen during August-September periods,although there has been a steady increase in ragweedpollen concentration in the Prague area over the lastfive years. Skin prick tests and/or specific IgEmeasurements with ragweed allergen were performed on94 children with pollen allergy in the Brno region in1995 and on 206, 210 and 229 adult allergic patientsin 1995, 1996 and 1997, respectively. Positive skinreaction or positive specific IgE to ragweed was foundin 22% children and in 25% (1995), 19% (1996) and 25% (1997) adults with pollen allergy. It isconcluded that ragweed does not seem to represent anyimminent major threat to the allergic population inthe Czech Republic until now, however, it remains apotentially very dangerous allergen.     

Changes in Endogenous Cytokinins During Germination and Seedling Establishment of <Emphasis Type="Italic">Tagetes minuta</Emphasis> L.

Endogenous cytokinins were quantified and identified in germinating achenes and developing seedlings of Tagetes minuta L. incubated at 25 °C over a 144 h period. The process of germination (radicle emergence) was completed 38 h after commencement of imbibition. Subsequent growth was considered to cover seedling establishment. Eighteen isoprenoid cytokinins, belonging to the zeatin (9), dihyrozeatin (5) and isopentenyladenine (4) groups and one aromatic cytokinin, benzyladenine, were identified. The total isoprenoid cytokinin concentration increased upon imbibition, reached a peak by 48 h and subsequently decreased with seedling development. The individual cytokinin groups and the respective derivatives within each group did, however, not follow such a consistent trend. During the course of the experiment, the ribotides and ribosides were present in the highest concentrations, reaching a peak at 48 h and decreasing thereafter. The free bases and O-glucoside remained at low levels throughout the experiment. Isopentenyladenine-9-glucoside increased dramatically in the developing seedlings and after 144 h was the predominate cytokinin. Benzyladenine was the only aromatic cytokinin detected throughout the experiment. It was present in high concentrations in the dry achenes and declined rapidly upon imbibition.     

Spatial Distribution and Temporal Variance of Fish Communities in the Channelized and Regulated Vltava River (Central Europe)

Spatial distribution and temporal variations of fish communities in a channelized portion of the Vltava River (Central Europe) were investigated from May to October 1992. Fish abundance and species number were collected monthly during diel samples in the main channel and a large oxbow. To determine differences in fish communities we chose the low-flow period when maximal differences in physical environment between habitats are expected. Fish community patterns from the main channel and oxbow differed only in abundance of ecological groups; the main channel had higher abundance of rheophilic species, whereas eurytopic species were more abundant in the oxbow. However, our analysis revealed significant differences in temporal variations between habitats. Fish abundance usually varied unpredictably over day-night periods in the main channel, whereas in the oxbow we observed a pronounced peak in fish abundance from morning to mid-afternoon. Diel changes in fish abundance in the oxbow corresponded to occurrence of low dissolved oxygen during afternoon and night-time periods. The effect of oxygen depletion induced by strong organic pollution limited the oxbow suitability for fishes. Similar habitats are usually occupied by limnophilic and phytophilic species that were absent in our samples. Our results suggested that man-induced high variability of physical environment decreased variability in fish community.     

Evaluation of the long term monitoring of phytoplankton assemblages in a canyon-shape reservoir using multivariate statistical methods

Hydrobiologia - Long term monitoring of the Římov Reservoir provided a data set for the analysis of phytoplankton composition and biomass in coincidence with physical, chemical,...