Magda Rybicka

Publications of Magda Rybicka

• [The influence of hepatitis B virus polymorphism on the progression of chronic liver disease].

  Authors: Magda Rybicka, Piotr Stalke, Urszula Charmuszko, Krzysztof Piotr Bielawski

  Postȩpy higieny i medycyny doświadczalnej (Online). 01/2011; 65:244-54.

  Hepatitis B virus (HBV) infection is one of the major human health problems worldwide. It is estimated that chronic HBV infection affects more than 350 million people globally. It is one of theHepatitis B virus (HBV) infection is one of the major human health problems worldwide. It is estimated that chronic HBV infection affects more than 350 million people globally. It is one of the leading causes of liver cirrhosis and hepatocellular carcinoma. High genetic variability is a characteristic feature of HBV as the viral polymerase lacks proofreading activity. The nucleotide substitution rate for HBV is 10-fold higher than for other DNA viruses. Genetic variations of HBV influence the clinical outcome of HBV infection. There are eight genotypes of hepatitis B virus (A-H) that have a distinct geographical distribution. There is clinical significance of HBV genotype in terms of disease activity, risk of progression to cirrhosis, the development of hepatocellular carcinoma and response to antiviral treatments. Moreover, polymorphism in HBV viral polymerase influences the development of HBV mutants resistant to nucleotide analogue treatment that is a consequence of treatment failure.

• Host response to the presence of Helicobacter spp. DNA in the liver of patients with chronic liver diseases.

  Authors: Magda Rybicka, Joanna Nakonieczna, Piotr Stalke, Krzysztof Piotr Bielawski

  Polish journal of microbiology / Polskie Towarzystwo Mikrobiologów = The Polish Society of Microbiologists. 01/2011; 60(2):175-8.

  Literature data indicate an association between the presence of Helicobacter spp. in the liver and the development of hepatocellular carcinoma (HCC). However, the role of H. pylori infections inLiterature data indicate an association between the presence of Helicobacter spp. in the liver and the development of hepatocellular carcinoma (HCC). However, the role of H. pylori infections in chronic liver diseases (CLD) remains controversial. The aim of this study was to detect Helicobacter spp. DNA in patients with CLD, and to investigate the host response to the presence of the bacterium in the liver. Helicobacter spp. DNA was detected in 59% samples. H.pylori was the most prevalent species (94%). We estimated the expression level of IL-1 and IL-8 genes. The presence of Helicobacter spp. did not have a significant effect on the gene expression of IL-8 and IL-1.

• [Helicobacter spp. infections in chronic liver damage].

  Authors: Magda Rybicka, Piotr Stalke, Krzysztof Piotr Bielawski, Joanna Nakonieczna

  Postȩpy higieny i medycyny doświadczalnej (Online). 01/2010; 64:386-95.

  Liver is a key organ responsible for organism’s homeostasis. A proper function of this organ is crucial for detoxification of metabolic products and regulation of metabolic processes ofLiver is a key organ responsible for organism’s homeostasis. A proper function of this organ is crucial for detoxification of metabolic products and regulation of metabolic processes of macromolecules (proteins, lipids, carbohydrates). The most important infectious factors, leading to liver damage, are primary hepatotropic viruses, particularly those causing chronic inflammation of the organ (HBV, HCV, HDV), which may subsequently cause cirrhosis and/or primary hepatocellular carcinoma. There has been a growing interest in Helicobacter spp. liver infections as a potential factor promoting injury of the organ towards hepatocellular carcinoma. The association between hepatocellular carcinoma and the presence of Helicobacters in the liver has been well documented in animal models (Helicobacter hepaticus versus liver cancer in mice). Some reports also indicate similar association in humans, where the presence of Helicobacter antigens in patients with liver cancer is detected more often in comparison to healthy or chronically infected population. Although the molecular mechanisms underlying such a phenomenon are not well known, the knowledge on this subject has considerably increased during recent years. The review presents data on the association between the presence of Helicobacter spp. in the liver and injuries of the organ, as well as the role that is played by the bacteria in chronic liver diseases.

• Superoxide dismutase is upregulated in Staphylococcus aureus following protoporphyrin-mediated photodynamic inactivation and does not directly influence the response to photodynamic treatment.

  Authors: Joanna Nakonieczna, Ewelina Michta, Magda Rybicka, Mariusz Grinholc, Anna Gwizdek-Wiśniewska, Krzysztof P Bielawski

  BMC microbiology. 01/2010; 10:323.

  Staphylococcus aureus, a major human pathogen causes a wide range of disease syndromes. The most dangerous are methicillin-resistant S. aureus (MRSA) strains, resistant not only to all β-lactamStaphylococcus aureus, a major human pathogen causes a wide range of disease syndromes. The most dangerous are methicillin-resistant S. aureus (MRSA) strains, resistant not only to all β-lactam antibiotics but also to other antimicrobials. An alarming increase in antibiotic resistance spreading among pathogenic bacteria inclines to search for alternative therapeutic options, for which resistance can not be developed easily. Among others, photodynamic inactivation (PDI) of S. aureus is a promising option. Photodynamic inactivation is based on a concept that a non toxic chemical, called a photosensitizer upon excitation with light of an appropriate wavelength is activated. As a consequence singlet oxygen and other reactive oxygen species (e.g. superoxide anion) are produced, which are responsible for the cytotoxic effect towards bacterial cells. As strain-dependence in photodynamic inactivation of S. aureus was observed, determination of the molecular marker(s) underlying the mechanism of the bacterial response to PDI treatment would be of great clinical importance. We examined the role of superoxide dismutases (Sod) in photodynamic inactivation of S. aureus as enzymes responsible for oxidative stress resistance. The effectiveness of photodynamic inactivation towards S. aureus and its Sod isogenic mutants deprived of either of the two superoxide dismutase activities, namely SodA or SodM or both of them showed similar results, regardless of the Sod status in TSB medium. On the contrary, in the CL medium (without Mn++ ions) the double SodAM mutant was highly susceptible to photodynamic inactivation. Among 8 clinical isolates of S. aureus analyzed (4 MRSA and 4 MSSA), strains highly resistant and strains highly vulnerable to photodynamic inactivation were noticed. We observed that Sod activity as well as sodA and sodM transcript level increases after protoporphyrin IX-based photodynamic treatment but only in PDI-sensitive strains. We confirmed that porphyrin-based photokilling efficacy is a strain-dependent phenomenon. We showed that oxidative stress sensitivity caused by the lack of both Sod enzymes can be relieved in the presence of Mn ions and partially in the presence of Fe ions. The fact that Sod activity increase is observed only in PDI-susceptible cells emphasizes that this is probably not a direct factor affecting S. aureus vulnerability to porphyrin-based PDI.