Biomedical subjects

Andrzej Małecki

Publications and source records attributed to Andrzej Małecki.

10 recordsLinked to original sources

PubMed2006

Phosphatidylinositol transfer protein expression altered by aging and Parkinson disease.

1. Phosphatidylinositol transfer proteins (PI-TP) are responsible for the transport of phosphatidylinositol (PI) and other phospholipids from endoplasmic reticulum to the other membranes and indirectly for lipid mediated signaling. Till now little is known about PI-TPs in brain aging and neurodegeneration. The aim of this study was to investigate expression of PI-TP in the brain during aging and in animal's model of Parkinson disease (PD) induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP). Moreover, in vitro, effect of 1-methyl-4-phenyl-pyridine cation (MPP(+)) on PI-TP, tyrosine hydroxylase (TH) protein level, and viability of cells was investigated. 2. Wistar rats 4, 24, and 36 months old and C57/BL mice and rat pheochromocytoma (PC12) cell line were used for the studies. Mice C57/BL received three injections of MPTP in saline at 2 h intervals in a total dose of 40 mg/kg and then after 3, 7, and 14 days they were used for the investigation. PC12 cells were treated with increasing concentration (50-300 microM) of MPP(+) for 24 h at 37 degrees C. The level of PI-TP(alpha and beta) and TH were determined using Western Blot analysis. 3. Our data indicated that PI-TP(alpha and beta) level decreased in brain of 36 months old rat by 20% comparing to the control value (4 months old). In animal's model of PD, PI-TP(alpha and beta) level was significantly lower by 85, 69, 64% in striatum at 3, 7, and 14 days after MPTP injection, respectively, compared to the control value. MPP(+) decreased PI-TP(alpha and beta), TH expression, and viability of PC12 cells in a dose-dependent manner. H(2)O(2), menadione, and NO donor significantly decreased the PI-TP level and viability of PC12 cells. 4. Our results indicate the lower protein expression of PI-TP(alpha and beta) in aged brain and in PD and suggest that oxidative stress may be responsible for the alteration of PI-TP.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

PubMed2006

[Importance of creatine kinase psychiatry--truths and myths].

Creatine kinase (CK) catalyzes the reversible transfer of the phosphoryl group from phosphocreatine to adenosine 5'-diphosphate (ADP), thus regenerating adenosine triphosphate (ATP). Creatine kinase genes are expressed in several tissues with high, fluctuating energy turnover, e.g. skeletal and cardiac muscle, brain and photoreceptor cells, and spermatozoa. Several isoenzymes of CK have been characterized: brain-type, muscle-type, and the hybrid isoenzymes, as well as the mitochondrial CK isoenzymes. Measurements of serum CK is a routine test in the diagnosis of acute myocardial infarction and various muscle disorders. Elevation of the serum CK level in psychiatric patients is a fairly nonspecific phenomenon. Most commonly, an elevated serum CK level is due to intramuscular injections, use of restraints or other intense isometric activity. Although it is still controversial, increased CK activity is one of basic criteria of neuroleptic malignant syndrome. Despite many studies on the importance of CK in postnatal brain and pathogenesis of psychiatric disorders, its role in psychiatry remains still mysterious.

Creatine Kinase↗

PubMed2005

Immunosuppressive immunophilin ligands attenuate damage in cultured rat astrocytes depleted of glutathione and exposed to simulated ischemia in vitro. Comparison with N-acetylcysteine.

The aim of the present study was to test the hypothesis that exposure of astrocytes depleted of glutathione (GSH) to simulated ischemia conditions in vitro and treated with immunosuppressant immunophilin ligands (cyclosporin A (CsA) and FK506) can increase intracellular GSH levels and that such mechanism may be responsible, at least in part, for their protective effects. In addition, we also compared the antioxidant properties of these immunosuppressants with N-acetylcysteine (NAC), a precursor of GSH synthesis. GSH depletion was induced by 24 h pretreatment with L-buthionine sulfoximine (BSO). Cultures of rat astrocytes were exposed to CsA (1-50 microM) and FK506 (1-1000 nM) and NAC (100 or 200 microM). We examined the effects of these compounds on apoptosis, cell viability, reactive oxygen species production and GSH content. Our study demonstrated that toxicity of simulated ischemia conditions were enhanced when intracellular GSH was depleted, and immunosuppressants (especially 100 nM FK506 and 10 microM CsA) effectively prevented ischemia toxicity in GSH depleted astrocytes. In addition, we have shown that interfering with the generation of GSH and attenuation, the rise of oxidative stress level by NAC may be a powerful tool for prevention of ischemia-induced glial cell damage.

Acetylcysteine↗

PubMed2004

[Culture of the corneal epithelium--comparison of the mitotic potential of limbal cells from living and cadaveric donors].

PURPOSE: We analyse effectiveness of corneal limbal cells' culture prepared from heart-beating organ donors, that include living donors and from cadaver donors buttons following 3 days storage in 4 degrees C in Likorol. MATERIAL AND METHODS: For experiment 12 adults (living and heart-beating organ donors) aged 28-63 (mean 46.3) and 12 corneal buttons of cadaver (aged 18-51, mean 34.1) were qualified. Tissue samples (1 mm2) were taken from superior corneal limbus. Sample from living donor obtained during routine operation was sent immediately to laboratory, as well as from heart-beating organ donor. The limbal biopsy of preserved cornea was taken after 3 days storage in 4 degrees C (Likorol). Samples were treated with trypsin/EDTA solution before culture. Collected cells in similar density in 1 ml of medium laid on dishes inserts, covered with fibrin (Tissucol) and cultured in presence of feeder layer of fibroblasts (L929 line). Epithelial cells were cultured for 14 days at 37 degrees C in humidified 5% CO2 atmosphere in supplemented 2:1 mixture of DMEM and Ham's F12. On the 14th day cells were collected. Number of cells per 1 ml of medium was counted by cytometer. Immunostaining for epithelium type (Keratin 3) was performed. RESULTS: The number of cells obtained from cadaver donors reached 184.2+/-14.9% whereas from living donors revealed 1013.1+/-104.2%, increase in relation to number of delivered cells. We observed only 0.83+/-0.3 colonies per microscopic area in cultures from preserved tissue versus 6.67+/-0.6 colonies in cultures from living donor. CONCLUSIONS: The preservation in 4 degrees C in Likorol significantly decreases proliferative potential of the corneal limbus.

Adult↗

PubMed2002

Piracetam and vinpocetine exert cytoprotective activity and prevent apoptosis of astrocytes in vitro in hypoxia and reoxygenation.

The aim of the present study was to establish whether piracetam (2-pyrrolidon-N-acetamide; PIR) and vinpocetine (a vasoactive vinca alkaloid; VINP) are capable of protecting astrocytes against hypoxic injury. Using the model of astrocyte cell culture we observed the cells treated with PIR and VINP during and after in vitro simulated hypoxia. Cell viability was determined by Live/Dead Viability/Cytotoxicity Assay Kit, LDH release assay and MTT conversion test. Apoptotic cell death was distinguished by a method of Hoechst 33342 staining underfluorescence microscope and caspase-3 colorimetric assay. In addition the intracellular levels of ATP and phosphocreatine (PCr) were evaluated by bioluminescence method. Moreover, the effect of the drugs on the DNA synthesis was evaluated by measuring the incorporation of [3H]thymidine into DNA of astrocytes. PIR (0.01 and 1 mM) and VINP (0.1 and 10 microM) were added to the medium both during 24 h normoxia, 24 h hypoxia or 24 h reoxygenation. Administration of 1 mM PIR or 0.1 microM VINP to the cultures during hypoxia significantly decreases the number of dead and apoptotic cells. The antiapoptic effects of drugs in the above mentioned concentrations was also confirmed by their stimulation of mitochondrial function, the increase of intracellular ATP, and the inhibition of the caspase-3 activity. The prevention of apoptosis was accompanied by the increase in ATP and PCr levels and increase in the proliferation of astrocytes exposed to reoxygenation. The higher concentration of VINP (10 microM) was detrimental in hypoxic conditions. Our experiment proved the significant cytoprotective effect of 1 mM PIR and 0.1 microM VINP on astrocytes in vitro.

Animals↗

PubMed2002

[Selected parameters of mechanical ventilation of the newborn infants after PDA surgical ligation].

In the above study we introduced initial results of pulmonary function measurements (PFM) in newborns with respiratory distress syndrome, after a surgical ligation of persistent ductus arteriosus (PDA). Material comprised seven newborns admitted in Department of Neonatology University of Medical Sciences in Poznań. Mean birth weight of our patient was 1072.9 +/- 187.1 g, and average maturity was 27.0 +/- 1.6. Diagnosis of PDA was established on the basis of clinical and Doppler examination. PFM was carried out with pneumotachometric method by VenTrak station immediately before and during 24 hours after the surgical intervention. Only mechanical breaths were analysed. We noted significantly higher values of dynamic compliance (Cdyn) and lower mean airways pressure (MAP) after ligation of PDA. The drop of resistance of airways (Raw) was small and had no statistical value.

Ductus Arteriosus, Patent↗

PubMedDate not supplied

Effect of antidepressants on the phospholipase A2 activity in plasma membranes of the rat brain cortex.

The aim of the present study was to establish whether antidepressants (ADs) of potentially different chemical structure and mechanisms of action affected the phospholipase A2 (PLA2) activity in plasma membranes of the rat brain cortex. It was decided to evaluate the influence of imipramine (IMI), amitriptyline (AMI), fluvoxamine (FLU), mianserin (MIA) and tianeptine (TIA) on PLA2 activity after an acute and long-term (4 weeks) drug administration. To study the time-related effects of FLU on PLA2 activity, animals were treated for 1, 7, 14 and 28 days. The experiments were performed on male Wistar rats. The PLA2 activity was determined by the method of Strosznajder and Strosznajder as well as Jelsema with slight modifications. It was shown that ADs significantly changed the PLA2 activity in plasma membranes of the rat brain cortex and the effects depended on the dose, time of administration and the structure of the drug. Tricyclic ADs, both classic (IMI and AMI) as well as atypical (e.g. TIA) inhibited PLA2 activity. It seems that FLU was the only antidepressant, which induced either inhibition or activation of PLA2 depending on time of administration. It may be suggested that PLA2 appears to be a common target for drugs showing quite different mechanisms of action.

Animals↗

PubMedDate not supplied

Immunophilin ligands decrease release of pro-inflammatory cytokines (IL-1beta, TNF-alpha and IL-2 in rat astrocyte cultures exposed to simulated ischemia in vitro.

The aim of present study was to evaluate the effects of immunophilin ligands (cyclosporin A, FK506 and rapamycin) on the simulated ischemia-induced release of pro-inflammatory cytokines (IL-1beta, TNF-alpha and IL-2) in rat primary astrocyte cell cultures. Astrocytes were exposed to cyclosporin A (CsA) (0.25, 0.5, 1, 10, 20 and 50 microM), FK506 (1, 10, 100, 1000 nM) and rapamycin (10, 100, 500 and 1000 nM). In vitro simulated ischemia significantly increased secretion of IL-1beta, TNF-alpha and IL-2 by astrocyte cultures deprived of microglia (by shaking and incubating with L-leucine methyl ester). CsA (at concentrations of 10-50 microM), FK506 (at all used concentrations) and rapamycin (in dose-dependent manner) significantly attenuated IL-1beta release after 24 h exposure to ischemic conditions. Immunophilin ligands at all used concentrations significantly decreased TNF-alpha levels in culture media after 24 h exposure to ischemia. Moreover, significant decrease in IL-2 secretion at 0.25, 0.5, 1 and 50 microM CsA and FK506 at concentrations of 100 and 1000 nM were observed. The results suggest that immunophilin ligands may regulate glial activity during ischemia by affecting the release of pro-inflammatory cytokines.

Animals↗

PubMedDate not supplied

Effect of aniracetam on phosphatidylinositol transfer protein alpha in cytosolic and plasma membrane fractions of astrocytes subjected to simulated ischemia in vitro.

Brain ischemia affects phosphoinositide metabolism and the level of lipid-derived second messengers. Phosphatidylinositol transfer proteins (PI-PTs) are responsible for the transport of phosphatidylinositol (PI) and other phospholipids through membranes. Isoform of PI-TPs (PI-TPalpha) is an essential component in ensuring substrate supply for phospholipase C (PLC). The current study was conducted to examine potential effect of aniracetam on PI-TPalpha expression and to characterize the PI-TPalpha isoform distribution between membrane and cytosol fractions of astrocytes exposed to simulated ischemia in vitro. After 8 h period of ischemia, the level of PI-TPalpha was significantly higher in cytosol (by about 28%) as well as in membrane fraction (by about 80%) in comparison with control. We have found that aniracetam treatment of astrocytes in normoxia significantly increased the level of PI-TPalpha in membrane fraction with a maximal effect at 0.1 microM concentration of aniracetam (by about 195% of control). In membrane fractions of ischemic cells, aniracetam increased PI-TPalpha expression in a concentration-dependent manner. In ischemic cells, aniracetam (10 microM) has elevated PI-TPalpha expression up to 155% and 428% in cytosolic and membrane fractions in comparison with ischemic untreated cells, respectively. The study has shown that aniracetam significantly activates PI-TPalpha in cell membrane fraction and this effect might be connected with previously described activation of MAP kinase cascade.

Animals↗

PubMedDate not supplied

Ebselen attenuates oxidative stress in ischemic astrocytes depleted of glutathione. Comparison with glutathione precursors.

In this study, we investigated the protective effect of ebselen, a seleno-organic compound with antioxidant activity, towards astrocyte degeneration caused by exposure to simulated in vitro ischemic conditions and simultaneous depletion of glutathione (GSH). Depletion of GSH was induced by 24 h pretreatment with L-buthionine-(S,R)-sulfoximine (BSO). In this experimental paradigm, we examined the effects of ebselen (1-40 microM) on apoptosis, mitochondrial function, reactive oxygen species (ROS) production, intracellular GSH level and mitochondrial transmembrane potential (MTP). In addition, we also compared the antioxidant potential of ebselen with cystine and methionine as precursors of GSH synthesis as well as with GSH ethyl ester. Our study demonstrated that toxicity of simulated ischemia conditions was enhanced when intracellular GSH was depleted. Treatment with ebselen, especially at concentrations of 20 and 40 microM prevented ischemia-induced cytotoxicity. Our study has shown that antiapoptotic effect of ebselen is associated with its strong antioxidant properties, preservation of MTP and possibly conservation of mitochondrial GSH during cytoplasmatic GSH depletion caused by oxidative damage. Also, promoting GSH synthesis by the delivery of its substrates, like cystine or inhibition of the efflux by methionine may be a powerful strategy to minimize cell damage in the nervous tissue after ischemia.

Animals↗