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Biomedical subjects

M Rybczyńska

Publications and source records attributed to M Rybczyńska.

13 recordsLinked to original sources
PubMed2000

[Detection of tubercle bacilli in clinical samples using genetic methods(PCR)compared with Lowenstein-Jensen culture methods].

The aim of this work was to compare data obtained using PCR assay for detection of Mycobacterium tuberculosis with culture. We report a test for detection of tubercle bacilli by PCR and identification at species level by capture plate hybridisation and enzyme-linked immunoassay. 222 clinical samples obtained from patients with confirmed and suspected tuberculosis were analysed. These specimens were tested parallelly by conventional culture on Löwenstein-Jensen slants and PCR test. For 205 samples a complete agreement between these methods was observed.

Enzyme-Linked Immunosorbent Assay↗
PubMed1998

The biochemical modification of the erythrocyte membranes from women with ovarian cancer.

The aim of our work was quantitative evaluation of the protein and phospholipid fractions of mature erythrocyte membranes separated from women with ovarian cancer. Blood was sampled from 30 women with ovarian cancer, aged 24-79 years, in the third stage of clinical progression of the disease. Phospholipids were separated from membranes by Müller's acidic extraction method and analysed in thin-layer two-dimensional chromatography. On the silica gel plates nine fractions of phospholipids were separated: sphingomyelin (SPH), phosphatidylethanolamine (PE), phosphatidlyserine (PS), phosphatidylcholine (PC), lysophosphatidylcholine (LPC), phosphatidic acid (PA), phosphatidylinositol (Ptd Ins), phosphatidylinositol-4-phosphate (Ptd Ins-4-P), phosphatidylinositol-4,5-diphosphate (Ptd Ins-4,5-P2). The activity of phospholipase C in erythrocyte membranes was determined by Akhrem's spectrophotometric method. Membrane proteins were separated by polyacrylamide gel electrophoresis, SDS-PAGE. It was shown that PS, SPH, LPC and PA fractions were significantly diminished. The concentration of Ptd Ins-4-P and Ptd Ins-4,5-P2 was significantly increased with simultaneous reduction in Ptd Ins level. The inhibition of phospholipase C reached 80%. The quantitative protein evaluation showed a statistically significant decrease in spectrin and a significant increase in 4.1 protein. The quantitative changes, observed in phospholipid and protein fractions, led to the restructuring of the erythrocyte membrane cytoskeleton, which may be connected to increased susceptibility to haemolysis of red blood cells.

Adult↗
PubMed1996

Ataxia telangiectasia heterozygotes and patients display increased fluidity and decrease in contents of sulfhydryl groups in red blood cell membranes.

In red blood cell membranes of ataxia telangiectasia mutated (ATM) homozygotes and heterozygotes, decreased values of the corrected fluorescence anisotropy and the anisotropy parameter were found, indicating increased fluidity and decreased microviscosity, respectively. These changes in membranes were accompanied by a decrease in SH-groups and an increase in malondialdehyde (MDA) contents. The content of MDA both in homozygotes and in heterozygotes exceeded roughly threefold the respective control values. Decreased content of GSH in red blood cells was found only in ATM homozygotes. The change most specific for the ATM gene appears to be the increase in fluidity, since only this parameter displays the proportionally greater changes in ATM homozygotes compared to ATM heterozygotes. The observations presented here may indicate that the ATM gene is expressed in precursors of red blood cells and deficiency of normal AT gene function may produce the changes which persist in circulating cells.

Ataxia Telangiectasia↗
PubMed1994

[Biochemical aspects of free radical mediated tissue injury].

A radical is any molecule that contains one or more unpaired electrons. Radicals are normally generated in many metabolic pathways. Some of these radicals can exist in a free form and subsequently interact with various tissue components resulting in dysfunction. The potential role of oxygen- and xenobiotic-derived free radical in the pathology of several human diseases has stimulated extensive research linking the toxicity of numerous xenobiotics and disease processes to a free radical mechanism.

Free Radicals↗
PubMed1982

Effect of various sulfur compounds on the transport system enzymes in human erythrocyte membranes.

We investigated the action of radioprotective agents: sodium S-(4-ethylphenylcarbonylmethylene)-thiosulfuric acid (SEPT), 2-(4-chlorophenyl)-thiazolidine (CPT) and dimethylsulfoxide (DMSO), on Na+/K+ATPase and Mg2+ATPase activity. SEPT inactivated more strongly Mg2+ATPase than Na+/K+ATPase, CPT dissolved in DMSO inhibited the activity of Mg2+ATPase, but did not affect that of Na+/K+ATPase. DMSO alone increased the activity of Mg2+ATPase and inhibited that of Na+/K+ATPase. Thus DMSO and CPT seem to act antagonistically on the activity of ATPases. The results indicate that radioprotectants strongly affect ATPases participating in membrane transport.

Acetophenones↗
PubMed1976

The influence of the known radioprotective compounds on the metabolism of red blood cells. I. Effect of cysteamine on the cellular level of the intermediates and coenzymes.

Cysteamine added to the human blood samples in the final concentration of 6.5 X 10(-3)m, 1,9 X 10(-2) M and 3,8 X 10(-2) M exerts a significant effect on the metabolism of erythrocytes. The chromatographic determination of carbohydrate intermediates and coenzymes in red blood cells indicates that in lower concentration of the drug the rate of anaerobic metabolism of glucose is increased. Higher concentration of cysteamine (3.8 X 10(-3) M) enhances aerobic catabolism of glucose in pentose shunt.

Blood Glucose↗
PubMed1976

The influence of the known radioprotective compounds on the metabolism of human red blood cell. Part II. The influence of cysteamine on enzymic systems.

The influence of cysteamine on the metabolic activity of red blood cells has been estimated in vitro. Cysteamine has a marked influence on the activity of mainly aldolase F-1, 6-P and glucose-6-P dehydrogenase in red blood cells in vitro. The anaerobic metabolism of erythrocytes is more active in the presence of lower doses of cysteamine. Higher concentrations of radioprotector stimulate the pentose phosphate shunt.

Anaerobiosis↗
PubMedDate not supplied

The influence of 2-acetoxy-1, 3-di(nitroimidazolyl)propane derivatives on human red blood cell membrane ATP-ase activity.

The effect of two nitroimidazoles, 2-acetoxyl-1,3-bis-(2'-methyl-4'-nitro-1'-imidazolyl)propane (Rs-029) and 2-acetoxy-1-(2'-methyl-4'-nitro-1'-imidazolyl)-3-(2''-methyl-5''-nitro- 1- nitroimidazolyl)propane (Rs-034) on ATP level and erythrocyte membrane ATP-ase activity was studied. The action of these compounds on erythrocyte membrane ATP-ase activity differed depending on the structure of nitroimidazoles. Only Rs-029 significantly inhibited (Na+K+) ATP-ase activity and activated Mg2+ ATP-ase. Both, Rs-029 and Rs-034 decreased ATP content in red blood cells after three hours incubation in the presence of plasma.

Adenosine Triphosphatases↗
PubMedDate not supplied

Effects of nitroheterocyclic sensitizers on erythrocyte membranes ATP-ase activity.

The effect of two nitroimidazoles, 1(2'-hydroxy-3'-chloropropyl)-2-methyl-4-nitroimidazol and 1(2'-hydroxy-3'-chloropropyl)-2-methyl-5-nitroimidazol and irradiation on erythrocyte membrane ATP-ase activity was studied. The action of nitroimidazole derivatives on the erythrocyte membrane ATP-ase activity differed depending on the nitro group position. 5-Nitroimidazole derivative in the concentration of 300 micrograms/mg protein inhibited significantly the non-irradiated erythrocyte membrane (Na+, K+) ATP-ase activity, while 4-NO2 in the concentration of 3 micrograms/mg protein influenced this activity, but only after an exposure at dose of 60 Krad. In the concentration of 300 micrograms/mg membrane protein it activated this ATP-ase.

Adenosine Triphosphatases↗
PubMedDate not supplied

Some biochemical and pharmacological aspects of free radical-mediated tissue damage.

Living in aerobic conditions carries a risk of oxidative stress, in connection with free radical deleterious action on tissues and cells. Free radical mechanisms have been implicated in the pathogenesis of many diseases, as well as in host defense against various invading microorganisms. A substantial body of evidence has been reported on free radical involvement in inflammation, ischaemia/reperfusion injury, atherosclerosis and many other pathologies. The aim of this paper is to review selected literature and opinions concerning free radical-induced damage to tissues and to present xenobiotic contribution to oxidative stress.

Aging↗
PubMedDate not supplied

Molecular changes in erythrocyte membranes induced by nitroimidazoles and radiation.

A damage of erythrocyte membranes by gamma-irradiation in the presence of nitroimidazole derivatives was shown by the demonstration of their effect on lipid peroxidation and SDS-PAGE protein pattern (1000 Gy) as well as on electron spin resonance (ESR) spectra of maleimide spin-labels attached to the membrane (for doses < or = 300 Gy). Erythrocyte membranes were labeled with two maleimide labels MAL-6 and MAL-M-3-PROXYL under strictly controlled and reproducible conditions with incubation at physiological temperature of 37 degrees C. The labels were bound to SH groups on the protein surface (weakly immobilized W-sites) as well as to internal SH-groups (strongly immobilized S-sites). The amplitude ratio W/S of the ESR signals was used for a monitoring of an influence of nitroimidazole drugs and gamma-irradiation. The influence appeared, even for the lowest doses, only when nitroimidazole drug was attached to the membrane. It was due to a destruction of spin-label paramagnetic centre both at W and S-sites and was related to the recombination processes during radiolysis connected with nitroimidazoles. It indicated a radiosensitivity of the nitroimidazoles. However, the persistent degradation of the membranes by the oxidative stress appeared above the threshold dose of 300 Gy determined from transformation of the W-sites into S-sites in ESR spectra. For the higher dose (1000 Gy) a fragmentation of the band 3 proteins was clearly seen as well as a partial damage of higher molecular-weight proteins with a simultaneous formation of much higher molecular-weight polymers.

Cyclic N-Oxides↗