Browsing by Author "Freivalds, Talivaldis"
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Item Morphological and Immunocytochemical Characterization of Paclitaxel-Induced Microcells in Sk-Mel-28 Melanoma Cells(2024-07) Simsone, Zane; Freivalds, Talivaldis; Harju, Līga; Miķelsone, Indra; Blāķe, Ilze; Bērziņš, Juris; Buiķis, Indulis; Department of Human Physiology and BiochemistryBiomarkers, including proteins, nucleic acids, antibodies, and peptides, are essential for identifying diseases such as cancer and differentiating between healthy and abnormal cells in patients. To date, studies have shown that cancer stem cells have DNA repair mechanisms that deter the effects of medicinal treatment. Experiments with cell cultures and chemotherapy treatments of these cultures have revealed the presence of small cells, with a small amount of cytoplasm that can be intensively stained with azure eosin, called microcells. Microcells develop during sporosis from a damaged tumor macrocell. After anticancer therapy in tumor cells, a defective macrocell may produce one or more microcells. This study aims to characterize microcell morphology in melanoma cell lines. In this investigation, we characterized the population of cancer cell microcells after applying paclitaxel treatment to a Sk-Mel-28 melanoma cell line using immunocytochemical cell marker detection and fluorescent microscopy. Paclitaxel-treated cancer cells show stronger expression of stem-associated ALDH2, SOX2, and Nanog markers than untreated cells. The proliferation of nuclear antigens in cells and the synthesis of RNA in microcells indicate cell self-defense, promoting resistance to applied therapy. These findings improve our understanding of microcell behavior in melanoma, potentially informing future strategies to counteract drug resistance in cancer treatment.Item Toluidine Blue Test for Sperm DNA Integrity and Elaboration of Image Cytometry Algorithm(2003-03) Erenpreisa, Jekaterina; Erenpreiss, Juris; Freivalds, Talivaldis; Slaidina, Maija; Krampe, Rasma; Butikova, Jelena; Ivanov, Andrey; Pjanova, DaceBackground: Sperm DNA integrity is of paramount importance in the prognosis of fertility. We applied image cytometry to a toluidine blue (TB) test we recently proposed. Methods: Sperm samples from 33 men were assayed for standard sperm parameters and classified as normal or abnormal. Sperm smears were subjected to the TB test, DNA denaturation testing with acridine orange (AO), and terminal deoxyuridine triphosphate biotin nick end labeling (TUNEL). In CCD image analysis, TB-stained sperm cell heads were microscopically assigned to one of four color groups (dark, blue, light violet, and light blue). The optical densities of 6,600 cells in green and red CCD images were used to elaborate an algorithm for discrimination of these groups. Results: The proportions of sperm in TB color groups, as estimated with the developed image cytometry algorithm, correlated with microscopic features. The number of TB dark cells correlated with the number of AO-red and TUNEL+ cells. The proportion of TB dark cells in normal samples did not exceed 35%. Light-blue sperm cell heads prevailed in normal samples, whereas dark and blue sperm cell heads dominated in abnormal samples. Conclusions: The TB test was suitable for the assessment of sperm cell DNA integrity. The elaborated image cytometry algorithm can be used for this purpose and for finer determination of sperm nucleus status.Item When Three Isn't a Crowd : A Digyny Concept for Treatment-Resistant, Near-Triploid Human Cancers(2019-07) Salmina, Kristine; Gerashchenko, Bogdan, I; Hausmann, Michael; Vainshelbaum, Ninel M.; Zayakin, Pawel; Erenpreiss, Juris; Freivalds, Talivaldis; Cragg, Mark S.; Erenpreisa, Jekaterina; Rīga Stradiņš University