Analysis of polymorphism and hepatic expression of duodenal cytochrome b in chronic hepatitis C.

BACKGROUND AND AIM: Pathological iron overload is commonly found in chronic hepatitis C (CHC) patients and considered as a negative prognostic factor of the disease. A single nucleotide polymorphism (SNP) rs884409 in duodenal cytochrome b gene (CYBRD1) is implicated in the pathogenesis of hemochromatosis. In our study we investigated the impact of the CYBRD1 genotype and expression on iron overload in CHC patients. METHODS: Liver biopsy specimens and whole blood samples from 243 patients with CHC were included in the study. Iron deposits in hepatocytes, serum markers of iron overload, and expression profile of gene-regulators of iron homeostasis were analyzed. Genotyping and analysis of gene expression of the CYBRD1 were performed. The frequency of SNP and the expression levels of CYBRD1 were compared between the groups of patients with and without markers of iron overload. RESULTS: The single nucleotide variant rs884409 G was associated with elevated serum iron levels, increased markers of liver inflammation, and oxidative stress. Hepatic expression of CYBRD1 was associated with the expression of Tfr2, Id1, and HO-1 genes, serum ferritin levels, and with increased iron accumulation in liver. CONCLUSION: These results implicate CYBRD1 involvement in iron homeostasis in CHC.

Antimicrobial photodynamic therapy with fulleropyrrolidine: photoinactivation mechanism of Staphylococcus aureus, in vitro and in vivo studies.

A family of N-methylpyrrolidinium fullerene iodide salts has been intensively studied to determine their applicability in antimicrobial photodynamic therapy (APDT). This study examined in vitro the efficacy of a C60 fullerene functionalized with one methylpyrrolidinium group to kill upon irradiation with white light gram-negative and gram-positive bacteria, as well as fungal cells, and the corresponding mechanism of the fullerene bactericidal action. The in vitro studies revealed that the high antistaphylococcal efficacy of functionalized fullerene could be linked to their ability to photogenerate singlet oxygen and superoxide anion. Following Staphylococcus aureus photoinactivation, no modifications of its genomic DNA were detected. In contrast, photodamage of the cell envelope seemed to be a dominant mechanism of bactericidal action. In in vivo studies, a 2 log10 reduction in the average bioluminescent radiance between treated and non-treated mice was reached. One day post APDT treatment, moist and abundant growth of bacteria could be observed on wounds of non-fulleropyrrolidine and dark control mice. APDT-treated wounds stayed visibly clear up to the third day. Moreover, cytotoxicity test on human dermal keratinocytes revealed great safety of using the sensitizer toward eukaryotic cells. These data indicate potential application of functionalized fullerene as antistaphylococcal sensitizer for superficial infections.

Fine-tuning recA expression in Staphylococcus aureus for antimicrobial photoinactivation: importance of photo-induced DNA damage in the photoinactivation mechanism.

Bacterial cell envelope is generally accepted as the primary target for a photo-induced oxidative stress. It is plausible that DNA damage occurs during the antimicrobial photoinactivation. Here we investigate the correlation between DNA damage and photoinactivation by evaluating the level of RecA-based DNA repair system in Staphylococcus aureus. By using exogenous photosensitizers (new methylene blue (NMB), toluidine blue O (TBO), 5,10,15,20-tetrakis(1-methyl-4-pyridinio)porphyrin tetra(p-toluenesulfonate) (TMPyP), zinc phthalocyanine (ZnPc), Rose Bengal (RB)) and ALA-induced endogenous porphyrin-dependent blue light (405 nm), several outcomes were observed: (i) an increase of DNA damage (from gel electrophoresis in DNA damage assay), (ii) an increase of recA expression (luminescence assay in recA-lux strain), and (iii) an increase of RecA protein level (Western blotting). When recA expression was repressed by novobiocin, or abolished by deleting the gene, S. aureus susceptibility towards photoinactivation was increased at approximately a hundred-fold. The absence of RecA increases DNA damage to yield bactericidal effect. In novobiocin-resistant mutant (gyrB), as opposed to wild type, neither RecA protein level nor cell's susceptibility was affected by photoinactivation (when novobiocin is present). This is to suggest that GyrB-dependent inhibition mediated recA repression. Therefore, we have established the role of RecA in DNA damage during photoinactivation. With the use of rifampicin mutation frequency and Ames tests, we demonstrated that photoinactivation did not increase S. aureus mutagenesis and potentially is not mutagenic toward eukaryotic cells. The results suggest that the treatment is considered safe. In conclusion, we provide an evidence that recA inhibitor may serve as therapeutic adjuvant for antimicrobial photoinactivation. Clinical relevance of our findings warrants further investigations.

Imidazoacridinone derivatives as efficient sensitizers in photoantimicrobial chemotherapy.

The objective of this study was to investigate a new potential photosensitizer (PS) in the photodynamic inactivation (PDI) of microorganisms in vitro (11 reference strains and 13 clinical isolates, representing common Gram-positive and Gram-negative human pathogens), with special emphasis on Candida albicans. We studied the light-induced cytotoxicity of the imidazoacridinone derivative C1330 toward fungal cells grown in planktonic form. We examined the influence of various parameters (time of incubation, PDI quencher effect, and C1330 accumulation in C. albicans cells) on the efficacy of light-dependent cytotoxicity. Additionally, we checked for the potential cyto- and phototoxic activity of C1330 against human dermal keratinocytes. In our research, we used a broadband incoherent blue light source (380 to 470 nm) with an output power of 100 mW/cm(2). In vitro studies showed that the C1330 action against C. albicans was a light-dependent process. C1330 was an efficient photosensitizer in the photodynamic inactivation of C. albicans, which reduced the growth of planktonic cells by 6.1 log10 units. Efficient accumulation of PS in the nucleus and vacuoles was observed after 30 min of incubation, which correlated with the highest photokilling efficacy. Significant changes in intracellular structure were observed upon illumination of C1330-incubated C. albicans cells. In the case of the human HaCaT cell line, approximately 40% of cells survived the treatment, which indicates the potential benefit of further study of the application of C1330 in photoantimicrobial chemotherapy. These data suggest that PDI may be a viable approach for the treatment of localized C. albicans infections.

Sub-lethal photodynamic inactivation renders Staphylococcus aureus susceptible to silver nanoparticles.

Staphylococcus aureus is a common etiological factor in infections of burns and other chronic wounds. The development of an effective and fast-acting treatment would be enormously beneficial and is highly desired. We focused on testing the bactericidal efficacy of photoinactivation using a known photosensitizer (protoporphyrin IX, PPIX) in sequential combination with silver nanoparticles against S. aureus. Using PPIX-based photoinactivation followed by silver nanoparticles we obtained a high bactericidal effect (7 log10 units reduction) with limited harmful effects on human epidermal keratinocytes. Moreover, we observed that the use of silver nanoparticles prevents bacterial re-growth 24 h post-PDI treatment. A sequential combination of photoinactivation and silver nanoparticles represents a potentially effective antibacterial approach.

Polymorphisms Related to Iron Homeostasis Associate with Liver Disease in Chronic Hepatitis C.

Dysregulation of iron metabolism in chronic hepatitis C (CHC) is a significant risk factor for hepatic cirrhosis and cancer. We studied if known genetic variants related to iron homeostasis associate with liver disease progression in CHC. Retrospective analysis included 249 CHC patients qualified for antiviral therapy between 2004 and 2014. For all patients, nine SNPs within HFE, TFR2, HDAC2, HDAC3, HDAC5, TMPRSS6, and CYBRD1 genes were genotyped. Expression of selected iron-related genes, was determined with qRT-PCR in 124 liver biopsies, and mRNA expression of co-inhibitory receptors (PD-1, Tim3, CTLA4) was measured in 79 liver samples. CYBRD1 rs884409, HDAC5 rs368328, TFR2 rs7385804, and TMPRSS6 rs855791 associated with histopathological changes in liver tissue at baseline. The combination of minor allele in HDAC3 rs976552 and CYBRD1 rs884409 linked with higher prevalence of hepatocellular carcinoma (HCC) during follow up (OR 8.1 CI 2.2-29.2; p = 0.001). Minor allele in HDAC3 rs976552 associated with lower hepatic expression of CTLA4. Tested polymorphisms related to iron homeostasis associate with histopathological changes in the liver. The presence of both HDAC3 rs976552 G and CYBRD1 rs884409 G alleles correlates with HCC occurrence, especially in the group of patients with elevated AST (>129 IU/L). rs976552 in HDAC3 could impact immunological processes associated with carcinogenesis in CHC.

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

BACKGROUND: 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 ß-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. RESULTS: 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. CONCLUSIONS: 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.

Molecular characteristics of community-associated methicillin-resistant Staphylococcus aureus strains for clinical medicine.

Infections caused by methicillin-resistant S. aureus strains are mainly associated with a hospital setting. However, nowadays, the MRSA infections of non-hospitalized patients are observed more frequently. In order to distinguish them from hospital-associated methicillin-resistant S. aureus (HA-MRSA) strains, given them the name of community-associated methicillin-resistant S. aureus (CA-MRSA). CA-MRSA strains most commonly cause skin infections, but may lead to more severe diseases, and consequently the patient's death. The molecular markers of CA-MRSA strains are the presence of accessory gene regulator (agr) of group I or III, staphylococcal cassette chromosome mec (SCCmec) type IV, V or VII and genes encoding for Panton-Valentine leukocidin (PVL). In addition, CA-MRSA strains show resistance to beta-lactam antibiotics. Studies on the genetic elements of CA-MRSA strains have a key role in the unambiguous identification of strains, monitoring of infections, improving the treatment, work on new antimicrobial agents and understanding the evolution of these pathogens.

The role of MR imaging in detection of hepatic iron overload in patients with cirrhosis of different origins.

BACKGROUND: There are many pathological conditions with hepatic iron overload. Classical definite diagnostic methods of these disorders are invasive and based on a direct tissue biopsy material. For the last years the role of MR imaging in liver diagnostics has been increasing. MRI shows changes of liver intensity in patients with hepatic iron overload. Changes in MR signal are an indirect consequence of change of relaxation times T2 and T2*, that can be directly measured. The purpose of the study was to evaluate usefulness of MR imaging in the detection of hepatic iron overload in patients with cirrhosis of different origins. METHODS: MR imaging at 1.5T was prospectively performed in 44 patients with liver cirrhosis who had undergone liver biopsy with histopathological assessment of hepatic iron deposits. In all patients the following sequences were used: SE, Express, GRE in T2 and T1-weighted images. Signal intensity (SI) was measured on images obtained with each T2 weighted sequence by means of regions of interest, placed in the liver and paraspinal muscles. The correlation between iron overload, histopathological score, serum ferritin and SI ratio was analyzed. RESULTS: In 20 patients with iron overload confirmed by the biopsy, the liver parenchyma demonstrated lower signal intensity than that of paraspinal muscles. This effect was visible only in 8 patients with hepatic iron overload in Express T2-weighted images. Higher signal intensity of liver than that of skeletal muscles on GRE - T2 weighted images was noted in 24 patients with cirrhosis and without elevated hepatic iron concentration. We observed a correlation between low and high iron concentration and liver to muscle SI ratio. CONCLUSION: MR imaging is a useful and fast noninvasive diagnostic tool for the detection of liver iron overload in patients with cirrhosis of different origins.Liver to muscle SI ratio in GRE-T2-weighted sequence facilitates to differentiate patients with low and high degree of hepatic iron overload, which correlates with the origin of liver cirrhosis.

The profile of ErbB/Her family genes copy number assessed by real-time PCR in parathyroid adenoma and hyperplasia associated with sporadic primary hyperparathyroidism.

Hyperparathyroidism (pHPT) is a relatively frequent endocrinopathy, however, the molecular mechanisms of its etiology remain poorly understood. This disorder is mainly associated with benign tumours (adenoma) and hyperplasia of the parathyroid, hence, the focus is directed also to genes that are likely to be involved in carcinogenesis. Among such genes are ErbB/Her family genes already used in diagnosis of other tumours (e.g., breast carcinoma) and reported also to play a role in development of endocrine lesions. So far, ErbB-1/Her-1/EGFR expression has been detected in pHPT-associated adenomas and hyperplasia as opposed to no expression in normal parathyroid tissue. Moreover, losses or gains of the fragments of chromosomes where ErbB/Her genes are located have been reported. In this study, the gene dosage of ErbB/Her family genes were determined for the first time in parathyroid adenomas, hyperplasia and morphologically unchanged tissue in order to establish their putative role in the development of the disease. Genomic DNA was isolated from 33 patients with sporadic hyperparathyroidism and the gene copy numbers were assessed using real-time PCR. The ErbB/Her genes' profile was unaltered in most of the examined samples. Two low-level amplifications of ErbB-1/Her-1/EGFR gene, two deletions of ErbB-2/Her-2, and six deletions of ErbB-4/Her-4 were found. The ErbB-3/Her-3 gene remained unaffected. No correlation with clinical parameters was found for any gene. Both the low number of alterations and a lack of their associations with clinical parameters exclude the prognostic value of the ErbB/Her genes family in parathyroid tumourigenesis. Nevertheless, the ErbB-4/Her-4 deletions seem to be interesting for further investigations, especially in the context of PTH secretion.

[Active efflux as the multidrug resistance mechanism]. / Czynne usuwanie leku z komórki jako jeden z mechanizmów opornosci bakterii na srodki przeciwdrobnoustrojowe i metody jego zwalczania.

Active efflux is a common resistance mechanism in a wide range of bacterial pathogens. It is responsible for the transport of such toxic compounds as drugs, toxins, and detergents. Pumps with broad substrate profiles promote the emergence of multidrug-resistant bacterial pathogens that are a particular threat to contemporary medicine, such as Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, and Salmonella enterica sv Typhimurium. One can distinguish five major class of transport systems on the basis of their structure and function: MFS (major facilitator superfamily), SMR (small multidrug-resistance family), MATE (multidrug and toxic compound extrusion family), ABC (ATP binding cassette superfamily), and RND (resistance nodulation cell division family). Substrate transport may include hydrogen proton exchange or energy generated via ATP hydrolysis. The transport is effectively regulated by local regulatory proteins.such as BmrR from Bacillus subtilis, or by the global bacterial regulatory system. Investigations into efflux pumps and their substrate profiles and regulatory mechanisms have led to the discovery of new therapeutics and pump inhibitors that could potentially become alternative and effective antimicrobial drugs. Additionally, some alternative therapies such as photodynamic inactivation could be more effective if the synergistic action of efflux pump inhibitors are used.Thus research into efflux transport systems seems to be an important element of contemporary medicine .

Neutrocyte-to-lymphocyte ratio predicts the presence of a replicative hepatitis C virus strand after therapy with direct-acting antivirals.

Residual HCV-RNA can persist in liver tissue and peripheral blood mononuclear cells (PBMCs) long after antiviral therapy of chronic hepatitis C in patients repeatedly negative for viral RNA in serum. This occult infection associates with impaired immune response and the risk of lymphoproliferative disorders or progressive liver disease. There are currently no monitoring strategies for patients after treatment. We investigated if serum inflammation markers and interferon lambda (IFNL) genotype can be predictors of the presence of HCV-RNA and the replicative HCV-RNA (-) strand in patients who reached sustained virological response after interferon-free therapy. Forty-two consecutive patients who remained HCV-RNA negative in serum 24 weeks after the end of treatment (EOT) and during the follow-up were enrolled. Total HCV-RNA and HCV-RNA (-) strand were detected using ultrasensitive RT-PCR in PBMCs collected 12-15 months after EOT. Polymorphisms within IFNL3-IFNL4 region (rs12979860 and ss469415590) were genotyped with allele-specific PCR. Viral RNA was found in PBMCs from 31 (74%) patients, and of those 29 (69%) were also positive for HCV-RNA (-). Neither normalization of alanine aminotransferase nor IFNL genotype predicted the presence of residual HCV-RNA. A significantly higher neutrocyte-to-lymphocyte ratio (NLR) 24 weeks after the start of treatment predicted elimination of replicative HCV-RNA strand (OR 0.23; 95% CI 0.10-0.86; P = 0.019). Patients with no HCV-RNA (-) in PBMCs showed a greater increase in neutrocyte count between EOT and baseline (P = 0.028). Lack of significant elevation of NLR after therapy with direct-acting antivirals could predict the presence of residual replicative HCV-RNA strand in PBMCs.

Development of Staphylococcus aureus tolerance to antimicrobial photodynamic inactivation and antimicrobial blue light upon sub-lethal treatment.

Antimicrobial photodynamic inactivation (aPDI) and antimicrobial blue light (aBL) are considered low-risk treatments for the development of bacterial resistance and/or tolerance due to their multitargeted modes of action. In this study, we assessed the development of Staphylococcus aureus tolerance to these phototreatments. Reference S. aureus USA300 JE2 was subjected to 15 cycles of both sub-lethal aPDI (employing an exogenously administered photosensitizer (PS), i.e., rose Bengal (RB)) and sub-lethal aBL (employing endogenously produced photosensitizing compounds, i.e., porphyrins). We demonstrate substantial aPDI/aBL tolerance development and tolerance stability after 5 cycles of subculturing without aPDI/aBL exposure (the development of aPDI/aBL tolerance was also confirmed with the employment of clinical MRSA and MSSA strain as well as other representatives of Gram-positive microbes, i.e. Enterococcus faecium and Streptococcus agalactiae). In addition, a rifampicin-resistant (RIFR) mutant selection assay showed an increased mutation rate in S. aureus upon sub-lethal phototreatments, indicating that the increased aPDI/aBL tolerance may result from accumulated mutations. Moreover, qRT-PCR analysis following sub-lethal phototreatments demonstrated increased expression of umuC, which encodes stress-responsive error-prone DNA polymerase V, an enzyme that increases the rate of mutation. Employment of recA and umuC transposon S. aureus mutants confirmed SOS-induction dependence of the tolerance development. Interestingly, aPDI/aBL-tolerant S. aureus exhibited increased susceptibility to gentamicin (GEN) and doxycycline (DOX), supporting the hypothesis of genetic alterations induced by sub-lethal phototreatments. The obtained results indicate that S. aureus may develop stable tolerance to studied phototreatments upon sub-lethal aPDI/aBL exposure; thus, the risk of tolerance development should be considered significant when designing aPDI/aBL protocols for infection treatments in vitro and in clinical settings.

Structural Transformation to Attain Responsible BIOSciences (STARBIOS2): Protocol for a Horizon 2020 Funded European Multicenter Project to Promote Responsible Research and Innovation.

BACKGROUND: Promoting Responsible Research and Innovation (RRI) is a major strategy of the "Science with and for Society" work program of the European Union's Horizon 2020 Framework Programme for Research and Innovation. RRI aims to achieve a better alignment of research and innovation with the values, needs, and expectations of society. The RRI strategy includes the "keys" of public engagement, open access, gender, ethics, and science education. The Structural Transformation to Attain Responsible BIOSciences (STARBIOS2) project promotes RRI in 6 European research institutions and universities from Bulgaria, Germany, Italy, Slovenia, Poland, and the United Kingdom, in partnership with a further 6 institutions from Brazil, Denmark, Italy, South Africa, Sweden, and the United States. OBJECTIVE: The project aims to attain RRI structural change in 6 European institutions by implementing action plans (APs) and developing APs for 3 non-European institutions active in the field of biosciences; use the implementation of APs as a learning process with a view to developing a set of guidelines on the implementation of RRI; and develop a sustainable model for RRI in biosciences. METHODS: The project comprises interrelated research and implementation designed to achieve the aforementioned specific objectives. The project is organized into 6 core work packages and 5 supporting work packages. The core work packages deal with the implementation of institutional APs in 6 European institutions based on the structural change activation model. The supporting work packages include technical assistance, learning process on RRI-oriented structural change, monitoring and assessment, communication and dissemination, and project management. RESULTS: The project is funded by Horizon 2020 and will run for 4 years (May 2016-April 2020). As of June 2018, the initial phase has been completed. The participating institutions have developed and approved APs and commenced their implementation. An observation tool has been launched by the Technical Assistance Team to collect information from the implementation of APs; the Evaluation & Assessment team has started monitoring the advancement of the project. As part of the communication and dissemination strategy, a project website, a Facebook page, and a Twitter account have been launched and are updated periodically. The International Scientific Advisory Committee has been formed to advise on the reporting and dissemination of the project's results. CONCLUSIONS: In the short term, we anticipate that the project will have a considerable impact on the organizational processes and structures, improving the RRI uptake in the participating institutions. In the medium term, we expect to make RRI-oriented organizational change scalable across Europe by developing guidelines on RRI implementation and an RRI model in biosciences. In the long term, we expect that the project would help increase the ability of research institutions to make discoveries and innovations in better alignment with societal needs and values. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/11745.

Prevalence of HBV genotypes in Central and Eastern Europe.

The importance of hepatitis B virus (HBV) genotypes for disease progression and response to interferon-alpha-based treatment is well established. While almost all patients in the Mediterranean area are infected with HBV genotype D, HBV genotype A is dominant in Northern Europe. However, the distribution of HBV genotypes is unknown for several Central and Eastern European countries. Data are described of 1313 HBsAg-positive patients recruited at 14 referral centers in eight countries. There were only very few cases of HBV genotype B, C, E, F, and H infection while HBV genotypes A and D were found in 42% and 48% of patients, respectively. Eight percent of patients had positive bands for more than one genotype using the hybridization assay. The frequency of genotype A was higher in Poland (77%) and the Czech Republic (67%) as compared to Hungary (47%), Lithuania (41%), Croatia (8%), and Germany (32%). In contrast, HBV genotype D was most frequent in Croatian, Romanian, and Russian patients with 80%, 67%, and 93% of cases, respectively. In conclusion, HBV genotype A versus D showed significantly different distribution patterns in Central and Eastern Europe which deserves consideration for national guidelines and treatment decisions.

The p53-mediated cytotoxicity of photodynamic therapy of cancer: recent advances.

Photodynamic therapy (PDT) is a promising modality for the treatment of both pre-malignant and malignant lesions. The mechanism of action converges mainly on the generation of reactive oxygen species which damage cancer cells directly as well as indirectly acting on tumor vasculature. The exact mechanism of PDT action is not fully understood, which is a formidable barrier to its successful clinical application. Elucidation of the mechanisms of cancer cell elimination by PDT might help in establishing highly specific, non-genotoxic anti-cancer treatment of tomorrow. One of the candidate PDT targets is the well-known tumor suppressor p53 protein recognized as the guardian of the genome. Together with its family members, p73 and p63 proteins, p53 is involved in apoptosis induction upon stress stimuli. The wild-type and mutant p53-targeting chemotherapeutics are currently extensively investigated as a promising strategy for highly specific anti-cancer therapy. In photodynamic therapy porphyrinogenic sensitizers are the most widely used compounds due to their potent biophysical and biochemical properties. Recent data suggest that the p53 tumor suppressor protein might play a significant role in porphyrin-PDT-mediated cell death by direct interaction with the drug which leads to its accumulation and induction of p53-dependent cell death both in the dark and upon irradiation. In this review we describe the available evidence on the role of p53 in PDT.

Photodynamic effect of protoporphyrin diarginate (PPArg2) on methicillin-resistant Staphylococcus aureus and human dermal fibroblasts.

The worldwide rise in the antibiotic resistance of bacteria forces the development of alternative antimicrobial treatments. A potential approach is photodynamic inactivation (PDI). The aim of the present study was to determine the phototoxicity of protoporphyrin diarginate (PPArg(2)) against methicillin-resistant Staphylococcus aureus and human dermal fibroblasts. Different concentrations (0 to 20 microM) of PPArg(2) and light dose of 6 J cm(-2) were tested. Cell viability was evaluated using the methylthiazoletetrazolium (MTT) assay. Incubation with 10 microM followed by illumination yielded a 3.6 log(10)-unit reduction in the viable count for Staphylococcus aureus. At the same experimental conditions, only 22.5% of the fibroblasts were photoinactivated. Protoporphyrin diarginate at concentrations up to 20 microM demonstrated no toxicity towards S. aureus or fibroblasts when not irradiated. These results suggest that the protoporphyrin diarginate exerts a high bactericidal effect against methicillin-resistant S. aureus strain without harming eukaryotic cells.

Photodynamic effect of lanthanide derivatives of meso-tetra(N-methyl-4-pyridyl)porphine against Staphylococcus aureus.

Photodynamic therapy (PDT), used for cancer treatment, is also an alternative method for eradication of drug-resistant bacteria. This method utilizes a nontoxic light-activated dye, called a photosensitizer, and visible light to produce reactive oxygen species that lead to bacterial cell death. The purpose of this study was to investigate the bactericidal effect of PDT using lanthanide derivatives of meso-tetra(N-methyl-4-pyridyl)porphine against Staphylococcus aureus strains. The new photosensitizers appeared to be photodynamically ineffective. No enhancement of antistaphylococcal activity of TMPyP was observed after the conjugation of the porphyrin with lanthanide ions. Additionally, a significant difference in the susceptibility of two bacterial strains to unmodified TMPyP was observed.

Bactericidal effect of photodynamic inactivation against methicillin-resistant and methicillin-susceptible Staphylococcus aureus is strain-dependent.

Staphylococcus aureus is one of the most important etiological factors responsible for nosocomial infections. Some of them may be life-threatening, especially in the case of immuno-compromised patients, causing bacteremia, endocarditis, sepsis or toxic-shock syndrome. Their multiresistance to antibiotics produces many therapeutic problems, and for this reason the development of a method alternative to antibiotic therapy is needed. It seems that photodynamic inactivation (PDI) may be an effective and alternative therapeutic option against both methicillin resistant (MRSA) and methicillin sensitive (MSSA) S. aureus strains. The aim of this study was to analyze the bactericidal effect of the PDI against 40 clinical MRSA and 40 MSSA clinical strains that were isolated from patients hospitalized in the Provincial Hospital in Gdansk. The ATCC strain 25904 has been used as a reference. Photodynamic inactivation by means of protoporphyrin diarginate as a photosensitizer was examined. It was observed that the bactericidal effect of the PDI was strain-dependent and ranged from 0 to 3 log(10)-unit reduction in viable counts. The mechanism underlying such a phenomenon is still not understood. Nevertheless, the correlation between the biofilm production ability and different strains response to PDI has been observed.

Compound heterozygote (C282Y/H63D) of hereditary hemochromatosis in a 16-year-old girl with hypoplastic kidney.

Iron-overload diseases are associated with primary or secondary disturbances of iron metabolism. Hereditary hemochromatosis, a genetically heterogeneous disease that is characterized by increased iron absorption and progressive deposition in parenchymal cells, may lead to organ damage and failure. Molecular studies have shown that hemochromatosis type 1 is predominantly due to a mutation in the HFE gene; there are 2 major mutations (C282Y and H63D). Disease symptoms are observed mostly after 40 years of age, often in men. We report the unusual case of a 16-year-old girl with an elevated serum iron level and a hypoplastic kidney. Identification of heterozygosity for the HFE gene mutation C282Y/H63D confirmed the diagnosis of hemochromatosis type 1. The early detection of hemochromatosis in the presented case may delay organ damage and failure due to iron overload.