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Akos Fábián

Publications and source records attributed to Akos Fábián.

4 recordsLinked to original sources

Cellular and serological changes in the peripheral blood of splenectomized and spleen autotransplanted mice.

BACKGROUND: Our department worked out a modified surgical form of spleen autotransplantation earlier, named "spleen apron method" introduced already into the clinical practice. Recently we tested the immunological changes in a group of patients autotransplanted with about 10-15% of their spleen, what was the at least always implantable amount after the severe splenic injuries. In the current work we aimed at measuring some cellular and serological changes in the peripheral blood of splenectomized and spleen autotransplanted inbred mice two and eight months after the operations in order to get more unambiguous results than that we could obtain in our patients with this technique. MATERIALS AND METHODS: We divided 96 two months old Balb/c female mice into eight groups (n = 12/group). The group of controls, sham operated, splenectomized and autotransplanted animals with two and eight months of survival time after the operations. During the autotransplantation we inserted the same amount of spleen, five slices, "chips," about 10-15% of total mass of spleen, into the greater omentum similarly as it was used in the patients. The concentration of serum proteins were measured by laser nephelometry. The lymphocyte subsets were analyzed by flow cytometry. RESULTS: We found that two months after the operations the number of CD 19+ B-cells increased in the splenectomized but decreased in the autotransplanted animals. Eight months after the operations the number of both CD3+ T and CD19+ B lymphocytes decreased both in the splenectomized and autotransplanted animals compared to the controls and sham operated mice. However, the numbers of T and B cells were slightly but not significantly higher in the autotransplanted than in the splenectomized mice. The serum level of IgM was also decreased in the splenectomized and autotransplanted mice at both time points, however, eight months after the operations the concentration of IgM was significantly higher in the autotransplanted group than in the splenectomized animals. CONCLUSION: The effects of autotransplanted "chips" were different at the various ages of the animals. Additionally, they showed some immunological benefit being quantitatively in accordance to the amount of the transplanted spleen. The elevated level of serum IgM what we found in the autotransplanted mice even with this amount of transplanted spleen eight months after the operations, however, might have the potentially greatest importance compared to splenectomy. These experiments can prove that the attempts for autotransplantation may have real perspectives but their efficacy depends on the amount of the successfully transplanted (saved) mass of spleen.

Animals↗

Selecting the right fluorophores and flow cytometer for fluorescence resonance energy transfer measurements.

BACKGROUND: Fluorescence resonance energy transfer applied in flow cytometry (FCET) is an excellent tool for determining supramolecular organization of biomolecules at the cell surface or inside the cell. Availability of new fluorophores and cytometers requires the establishment of fluorophore dye pairs most suitable for FCET measurements. METHODS: A gastric tumor cell line (N87) was labeled for major histocompatibility complex class I heavy chain and beta2-microglobulin with antibodies conjugated with fluorescein- and indocarbocyanine-like fluorophores and analyzed in FCET measurements on a cell-by-cell basis using three flow cytometers: FACSCalibur, FACSDiVa, and FACSArray. RESULTS: Normalized fluorescence intensity values were measured and normalized energy transfer efficiencies, spectral overlap integrals, and crucial dye- and instrument-dependent parameters were calculated for all matching pairs of seven fluorophores on the three commercial cytometers. The most crucial parameter in determining the applicability of the donor-acceptor pairs was the normalized fluorescence intensity and the least important one was the spectral overlap. CONCLUSIONS: On the basis of available laser lines, the optimal dye pair for all three cytometers is the Alexa546-Alexa647 pair, which produces high energy transfer efficiency values and has the best spectral characteristics with regard to laser excitation, detection of emission, and spectral overlap.

Cell Line, Tumor↗

Computer program for analyzing donor photobleaching FRET image series.

BACKGROUND: The photobleaching fluorescence resonance energy transfer (pbFRET) technique is a spectroscopic method to measure proximity relations between fluorescently labeled macromolecules using digital imaging microscopy. To calculate the energy transfer values one has to determine the bleaching time constants in pixel-by-pixel fashion from the image series recorded on the donor-only and donor and acceptor double-labeled samples. Because of the large number of pixels and the time-consuming calculations, this procedure should be assisted by powerful image data processing software. There is no commercially available software that is able to fulfill these requirements. METHODS: New evaluation software was developed to analyze pbFRET data for Windows platform in National Instrument LabVIEW 6.1. This development environment contains a mathematical virtual instrument package, in which the Levenberg-Marquardt routine is also included. As a reference experiment, FRET efficiency between the two chains (beta2-microglobulin and heavy chain) of major histocompatibility complex (MHC) class I glycoproteins and FRET between MHC I and MHC II molecules were determined in the plasma membrane of JY, human B lymphoma cells. RESULTS: The bleaching time constants calculated on pixel-by-pixel basis can be displayed as a color-coded map or as a histogram from raw image format. CONCLUSION: In this report we introduce a new version of pbFRET analysis and data processing software that is able to generate a full analysis pattern of donor photobleaching image series under various conditions. .

Algorithms↗

[Comparative investigation of the hematologic and immunologic effects of splenectomy and spleen autotransplantation in mice].

We have analysed the hematological and immunological effects of the Furka's spleen chip method of autotransplantation in Balb/c mice two and eight months after splenectomy and autotransplantation. Our results showed that the autotransplants had positive effect on the partial restoration of the damaged elements of both cellular and humoral immunity appearing after splenectomy. However, these beneficial effects may have some dependence of time and species.

Animals↗