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T Płoszaj

Publications and source records attributed to T Płoszaj.

8 recordsLinked to original sources
PubMed2001

Expression of apoptosis-related proteins in involuting mammary gland of sow.

The expression of apoptosis-related proteins: TGF-beta1 (local inductor), TGF-beta-receptor, Bax (promoter), Bcl-2 (inhibitor) and CPP-32 (executor of apoptosis); the subcellular distribution of Bax; as well as the number and morphology of apoptotic cells in low-, moderate-, and high-involuted mammary glands of sow (four to six days after weaning) were investigated. The immunohistochemical study demonstrated a statistically significant increase in the integrated optical density (IOD) of lobuloalveolar mammary tissue labelling with anti-Bax antibody from low- through moderate-, to high-involuted glands. The immunoelectron microscopy revealed that Bax was localised in the cytosol, on the membranes of mitochondrium and rough endoplasmic reticulum, in nuclear envelope pores, and over heterochromatin of mammary epithelial cells. The increase in Bax/Bcl-2 ratio (2.3, 2.6 and 5.6 for low-, moderate-, and high-involuted glands, respectively) indicated the increasing susceptibility of mammary epithelial cells to apoptosis in the course of involution. The highest Bax/Bcl-2 ratio in high-involuted glands coincided with the highest expression of CPP-32 (caspase 3), TGF-beta1 and TGF-beta1 receptor. The number of apoptotic cells (simultaneous TUNEL and Hoechst 33342 staining) was 2.7, 3.4 and 3.8% for low-, moderate-, and high-involuted glands, respectively. The ultrastructural evaluation showed characteristic morphological features of apoptosis such as: margination and condensation of chromatin; pyknosis and fragmentation of the nucleus; and formation of apoptotic bodies. Phagocytosis of apoptotic cells by macrophages was also documented. The results of the present study suggest the involvement of Bax/Bcl-2 check-point in the regulation, CPP-32 in the execution, but TGF-beta1 in the induction of apoptosis of mammary epithelial cells in the involuting mammary gland of sow.

Animals↗
PubMed2000

Inhibition of ornithine decarboxylase by alpha-difluoromethylornithine induces apoptosis of HC11 mouse mammary epithelial cells.

The effect of a-difluoromethylornithine (DFMO) on the apoptosis of HC11 mouse mammary epithelial cells was investigated. The involvement of reactive oxygen species (ROS) and Bcl-2 protein in the mechanism of apoptosis induced by ornithine decarboxylase (ODC) inhibition was also assessed. DFMO (0.1, 1 and 5mM) induced apoptosis of HC11 cells in dose- and time-dependent manner. Apoptosis manifests itself with morphological features like: cell shrinkage, condensation of chromatin, pyknosis and fragmentation of nucleus, followed by secondary necrosis (putrosis). The decrease in the nuclear DNA contents appearing as the hypodiploidal peak sub-G1 in the DNA histogram was not dependent on the presence of prolactin (5 microg/ml) in DFMO-treated cultures. Apoptosis induced by ODC inhibition was associated with a rapid increase in ROS concentration in HC11 cells observed within 1 h after DFMO treatment. The down-regulation of Bcl-2 as a decrease in cell number expressing bcl-2 and a lowered Bcl-2 protein content in cells expressing this protooncogene was also noted. The administration of putrescine (50 microM) lowered the number of early-apoptotic, late-apoptotic and necrotic cells. Moreover, it increased the number of cells expressing bcl-2. In conclusion, the disturbance of cellular polyamine homeostasis by inhibition of their synthesis enhances mammary epithelial cell susceptibility to apoptosis. It may occur in the mammary gland at the end of lactation, when the depletion of circulating lactogenic hormones and activation of intra-mammary apoptogenic factors expression take place.

Animals↗
PubMed2000

Expression and subcellular redistribution of Bax during TGF-beta1-induced programmed cell death of HC11 mouse mammary epithelial cells.

The effect of TGF-beta1, an auto/paracrine antiproliferative and apoptogenic factor on Bax transcript level (RT-PCR), subcellular distribution of Bax protein (immunoelectron microscopy), Bcl-2 protein level and apoptotic cell number (flow cytometry with FITC-conjugated monoclonal anti-Bcl-2 antibody and DNA stained with DAPI) in HC11 mouse mammary epithelial cells was examined. TGF-beta1 increased Bax transcript level (evaluated by Bax mRNA/GAPDH mRNA ratio) and stimulated Bax protein movement from cytosol to organellar membranes, mainly mitochondrial, during 60 min. The new observation is the presence of Bax on channel membranes of Golgi apparatus and translocation of Bax from cytosol to the fibrous nucleoplasm via nuclear envelope pores (especially after 120 min. of cell exposure to TGF-beta1). Prolactin protected HC11 cells against TGF-beta1-induced PCD, which could occur at two levels: 1) TGF-beta1 expression, through the decrease of TGF-beta1 transcript content, and 2) Bax/Bcl-2 checkpoint, through down-regulation of Bax and up-regulation of Bcl-2. In conclusion, Bax and Bcl-2 proteins are implicated in the mechanism of TGF-beta1-induced PCD and antiapoptotic action of prolactin in HC11 mouse mammary epithelial cells. The activation of transcription and redistribution of Bax from cytosol to organellar membranes and nucleus constitute the early events in the cellular response to TGF-beta1.

Animals↗
PubMed1998

Expression of bcl-2 and bax in TGF-beta 1-induced apoptosis of L1210 leukemic cells.

TGF-beta1 is a multifunctional regulatory peptide (25 kDa) inducing growth arrest and apoptosis in many normal and neoplastic cells. In the present study, the involvement of proapoptotic (bax) and antiapoptotic (bcl-2) genes in the molecular mechanism of TGF-beta1-induced apoptosis of L1210 leukemic cells was investigated. Bax transcript was measured using the RT-PCR method with GAPDH as a "housekeeping gene" control, whereas Bcl-2 protein was determined using flow cytometry (FITC-conjugated monoclonal anti-Bcl-2 antibody and FITC-conjugated mouse anti-IgG1 antibody as a negative control). Apoptosis was evaluated using fluorescence microscopy and flow cytometry after cell staining with DAPI and sulforhodamine or propidium iodide and Hoechst 33342. ROS generation was assessed by flow cytometry using the oxidation-sensitive fluorescent marker C-DCDHF-DA. The response of L1210 leukemic cells to TGF-beta1 was two-directional: 1) partial arrest of the cell cycle at G1-S transition, and 2) induction of apoptotic cell death. TGF-beta1 increased the number of leukemic cells with typical morphological features of apoptosis: cell shrinkage, condensation of chromatin, pyknosis and fragmentation of nuclei, followed by secondary necrosis. DNA cleavage led to a decrease of the nuclear DNA content and the appearance of a hypodiploid peak sub-G1 in the DNA histogram. The extraction of low-molecular weight DNA fragments from apoptotic cells showed that TGF-beta1-induced apoptosis concerned first of all the cells from G1 phase. Two phases of intracellular ROS generation in TGF-beta1-treated cultures were observed: the first (rapid, 60 min after TGF-beta1 administration), and the second (slow, occurring between 24 and 48h of experiment, respectively). The increase of apoptotic cell number in TGF-beta1-treated cultures (2% FCS/RPMI 1640) was associated with the decrease of cell number expressing bcl-2, and with a significant drop of Bcl-2 level in the remaining cells after 24 h. The dose-dependent relationship between TGF-beta1 concentration and Bcl-2 level was nonlinear and described by power series regression. The lowest Bcl-2 level was noted at 1 ng/ml of TGF-beta1 concentration. The increase of Bax mRNA:GAPDH mRNA ratio was observed 3h after TGF-beta1 (1 ng/ml) administration to both the maintenance (2% FCS/RPMI) and growth promoting (10% FCS/RPMI) medium. Regardless of TGF-beta1 treatment, the quantity of Bax transcript was dependent on FCS concentration, being higher in the growth promoting medium. The results of this study indicate that bax may function as a primary response gene and together with lowered Bcl-2 level may determine the induction of apoptotic process in L1210 leukemic cells exposed to TGF-beta1.

Animals↗
PubMed1998

[Antioxidative mechanisms in response to reactive forms of oxygen, apoptosis and differentiation of myogenic cells].

In this paper regard was put on contemporary matters related to apoptosis of myogenic cells of different types (myocardium, visceral, skeletal muscle) and updated theories on the action mechanisms of free radicals and their contribution to this process. Concern was put on the activity of certain growth factors and antioxidants belonging to group of polyphenols on the extent of apoptosis in myoblasts held in culture. Similarities between the pathways depicting the process of muscle differentiation and resistance to programmed cell death are presented. The concept of myogenic cell differentiation and implications to apoptosis induced by particular oxidants is extensively discussed.

Animals↗
PubMed1997

Polyamines in goat's colostrum and milk.

The concentration and secretion of putrescine (PTR), spermidine (SPD), and spermine (SPM) was examined in colostrum and milk of 60 dairy goats (Polish White and German Brown) during 90 days of lactation. It has been found that milk polyamine pattern is related to breed, age, offspring number, lactation period, milking time, and individual goat-to-goat variations. The mean level of PTR and SPD was significantly higher, whereas SPM level was significantly lower in German Brown than Polish White goats. These differences were maintained during whole observation period (90 days after parturition). Elder goats, bearing two and three kids, secreted colostrum with a higher concentration of PTR and a lower concentration of SPD than young goats having one kid. There was a highly significant positive relationship between the age or litter total weight and PTR concentration in colostrum of Polish White goats. In contrast to PTR, the SPD level was negatively correlated with the age or litter total weight. The daily secretion of PTR, SPD, and SPM progressively increased from the 1st to 90th day of lactation. It was dependent on the increase of milk secretion rate, which could be illustrated by the highly significant correlation between daily milk yield and secretion of SPD in milk of German Brown and Polish White goats. The concentration of SPD in milk sampled in the evening was usually higher than in that from morning milking, however, significant only in the case of German Brown goats. In general, goat's colostrum and milk are rich in polyamines, which the total concentration is the highest when compared to milk of other mammals examined so far (e.g., human, rat, sow, and cow).

Animals↗
PubMed1995

Polyamines in cow's and sow's milk.

There were considerably interspecies, individual, lactation and age related variabilities in the concentration of spermidine and spermine in cow's and sow's milk. Concentration of spermidine was similar in cow's and sow's milk, whereas spermine level was higher in sow's milk. The level of spermine was higher than spermidine throughout the lactation in sow's milk, whereas spermine in cow's milk was secreted only at the beginning of lactation (collostrum and milk of the first month of lactation). The peak of spermidine and spermine concentration occurred in the collostrum and milk between the 1st and 3rd week of lactation in cow and sow, respectively. There was a significant positive relationship between milk yield and spermidine secretion in cow as well as between the number of piglets and milk spermidine concentration in sow.

Age Factors↗