Nursing in Albania: A Catalytic Force in Transforming Health Professionals and Health Care.

PURPOSE: Transitions in nursing education and professionalism that align with global nursing standards are elucidated as critical success factors in transforming health professionals and health care in Albania. Progressive educational and regulatory pathways throughout the 2000s (1999-2020) are emphasized for their impact on the Albanian health system, including the achievement of universal healthcare coverage. METHODS: Data collected by the Ministry of Health and Sport and the Regulatory Authority for nursing and other healthcare professions in Albania were analyzed and outcomes explicated with regard to Albania's major health challenges. DISCUSSION AND CONCLUSIONS: Three milestones affirmed nursing as a driving force in the Albanian healthcare system: (a) nurses constitute the largest health professional workforce via a nurse-patient ratio of 1:400 in contrast to a physician-patient ratio of 1:2,500; (b) nurses are frontline care providers via clinical leadership in the management of primary healthcare centers, which ensure universal healthcare coverage; and (c) nurses are first responders via their presence and compassionate caring in the primary healthcare centers, including making critical shifts in converting primary healthcare centers to urgent care centers as needed. CLINICAL RELEVANCE: Nursing advancements have implicated quality care and professionalism in Albania across the health professions via three critical pathways: (a) health professional education at a university degree level for entry into practice (since 1999), which was prompted by and driven by nursing's quest to be a self-regulated profession (achieved in 2007); (b) healthcare global standards sparked by nursing's mandate toward professional autonomy, as achieved via regulatory procedures and policies; and (c) interprofessional healthcare initiatives that serve as collaborative platforms for innovative educational, clinical, and research projects.

Amyloid beta peptide (1-42)-mediated antioxidant imbalance is associated with activation of protein kinase C in red blood cells.

Glycolysis and pentose phosphate pathway (PPP) in red blood cell (RBC) are modulated by the cell oxygenation state. This metabolic modulation is connected to variations in intracellular nicotinamide adenine dinucleotide phosphate-reduced form (NADPH) and adenosine triphosphate (ATP) levels as a function of the oxygenation state of the cell, and, consequently, it should have physiologic relevance. In the present study, we analysed the effects of amyloid beta peptide (1-42) (Abeta) on RBC metabolism and its relationship with the activity of protein kinase C (PKC). Our results showed that metabolic response to Abeta depended on the degree of cell oxygenation. In particular, under high O2 pressure, in Abeta-treated RBC, glucose metabolized through PPP approached that metabolized by RBC under low O2 pressure, differently to that observed in untreated cells. The effect of Abeta on RBC metabolism was paralleled by increase in PKC enzyme activity, but cytosolic Ca2+ concentration does not seem to be involved in this mechanism. Incubation of Abeta-treated RBC with a specific inhibitor of PKC partially restores PPP flux. A possible rationalization of the different metabolic behaviours shown by RBC following Abeta treatment is proposed. It takes into account the known post-translational modifications to cytoskeleton proteins induced by PKC. The reduction in PPP flux may lead to a weakened defence system of antioxidant reserve in RBC, becoming a source of reactive species, and, consequently, its typical, structural and functional features are lost. Therefore, oxidative stress may outflow from the RBC and trigger damage events in adjacent cells and tissue, thus contributing to vascular damage.

Circulating tumour cells and cancer stem cells: a role for proteomics in defining the interrelationships between function, phenotype and differentiation with potential clinical applications.

Research on the discovery and implementation of valid cancer biomarkers is one of the most challenging fields in oncology and oncoproteomics in particular. Moreover, it is generally accepted that an evaluation of cancer biomarkers from the blood could significantly enable biomarker assessments by providing a relatively non-invasive source of representative tumour material. In this regard, circulating tumour cells (CTCs) isolated from the blood of metastatic cancer patients have significant promise. It has been demonstrated that localised and metastatic cancers may give rise to CTCs, which are detectable in the bloodstream. Despite technical difficulties, recent studies have highlighted the prognostic significance of the presence and number of CTCs in the blood. Future studies are necessary not only to detect CTCs but also to characterise them. Furthermore, another pathogenically significant type of cancer cells, known as cancer stem cells (CSCs) or more recently termed circulating tumour stem cells (CTSCs), appears to have a significant role as a subpopulation of CTCs. This review discusses the potential application of proteomic methodologies to improve the isolation and characterisation of CTCs and to distinguish between CTCs with a poor clinical significance and those with important biological and clinical implications.

Molecular interactions of hemoglobin with resveratrol: potential protective antioxidant role and metabolic adaptations of the erythrocyte.

This article reports the role of resveratrol in the erythrocyte as a result of its interaction with hemoglobin and describes the effect of this interaction on the metabolism, the redox state, and the release of ATP. The drug crosses the erythrocyte membrane and binds to hemoglobin, altering its modulation and the release of ATP. Our study correlates the variation of the phosphorylation balance induced by resveratrol with the change in the intracellular concentration of ATP and with the decrease in ATP release from red blood cell and the consequent paracrine alteration on the vascular epithelium. Molecular docking calculations indicate larger specificity of binding for oxy-hemoglobin that correlates well with the stabilization of the R-quaternary structure and with the functional modulation of resveratrol on the protein. Finally, we locate a putative binding site at the central cavity of hemoglobin and characterize its key interacting residues with the drug. Computational results support the assumption that resveratrol may act as a protector agent against oxidative protein damage by interacting with hemoglobin.

Early onset of Chanarin-Dorfman syndrome with severe liver involvement in a patient with a complex rearrangement of ABHD5 promoter.

BACKGROUND: α/ß-hydrolase domain-containing protein 5 (ABHD5) plays an important role in the triacylglycerols (TAG) hydrolysis. Indeed, ABHD5 is the co-activator of adipose triglyceride lipase (ATGL), that catalyses the initial step of TAG hydrolysis. Mutations in ABHD5 gene are associated with the onset of Chanarin-Dorfman syndrome (CDS), a rare autosomal recessive lipid storage disorder, characterized by non-bullous congenital ichthyosiform erythroderma (NCIE), hepatomegaly and liver steatosis. CASE PRESENTATION: We describe here a 5-years-old Brazilian child who presented with NCIE at birth and diffuse micro and macro-vesicular steatosis on liver biopsy since she was 2 years old. Molecular analysis of coding sequence and putative 5' regulatory region of ABHD5 gene was performed. A homozygous novel deletion, affecting the promoter region and the exon 1, was identified, confirming the suspected diagnosis of CDS for this patient. RT-PCR analysis showed that the genomic rearrangement completely abolished the ABHD5 gene expression in the patient, while only a partial loss of expression was detected in her parents. This is the first report describing the identification of a large deletion encompassing the promoter region of ABHD5 gene. The total loss of ABHD5 expression may explain the early onset of CDS and the severe liver involvement. After molecular diagnosis, the patient started a special diet, poor in fatty acids with medium chain triglycerides (MCT), and showed hepatic and dermatologic improvement in spite of severe molecular defect. CONCLUSIONS: This case report extends the spectrum of disease-causing ABHD5 mutations in CDS providing evidence for a novel pathogenic mechanism for this rare disorder. Moreover, our preliminary data show that early diagnosis and prompt treatment of neutral lipid accumulation might be useful for CD patients.

Advanced tools for BRCA1/2 mutational screening: comparison between two methods for large genomic rearrangements (LGRs) detection.

BACKGROUND: Currently, multiplex ligation-dependent probe amplification (MLPA) is the most commonly used technique for the detection of large genomic rearrangements (LGRs) in the BRCA1/2 genes. However, a very fast assay, the BRCA1/2 multiplex amplicon quantification (MAQ), has been recently developed by Multiplicom. METHODS: As no data regarding the application of MAQ method to BRCA1/2 genes are available in literature, here we compared for the first time the performance of the MAQ assay with MLPA by using several positive BRCA1/2 LGRs DNA samples (previously tested by MLPA). RESULTS: MAQ method was able to detect all BRCA1/2 LGRs and no false-positive or -negative results were obtained in independent repetitive experiments. CONCLUSIONS: We can affirm that MAQ, as well as MLPA method, results to be valid and reproducible tools for molecular diagnostics and we are confident that this assay can be used for BRCA1/2 mutational screening as a fast and safe alternative to MLPA, particularly in the first line of analysis.

Probing the stability of the "naked" mucin-like domain of human α-dystroglycan.

BACKGROUND: α-Dystroglycan (α-DG) is heavily glycosylated within its central mucin-like domain. The glycosylation shell of α-dystroglycan is known to largely influence its functional properties toward extracellular ligands. The structural features of this α-dystroglycan domain have been poorly studied so far. For the first time, we have attempted a recombinant expression approach in E. coli cells, in order to analyze by biochemical and biophysical techniques this important domain of the α-dystroglycan core protein. RESULTS: We expressed the recombinant mucin-like domain of human α-dystroglycan in E. coli cells, and purified it as a soluble peptide of 174 aa. A cleavage event, that progressively emerges under repeated cycles of freeze/thaw, occurs at the carboxy side of Arg461, liberating a 151 aa fragment as revealed by mass spectrometry analysis. The mucin-like peptide lacks any particular fold, as confirmed by its hydrodynamic properties and its fluorescence behavior under guanidine hydrochloride denaturation. Dynamic light scattering has been used to demonstrate that this mucin-like peptide is arranged in a conformation that is prone to aggregation at room temperature, with a melting temperature of ~40°C, which indicates a pronounced instability. Such a conclusion has been corroborated by trypsin limited proteolysis, upon which the protein has been fully degraded in less than 60 min. CONCLUSIONS: Our analysis indirectly confirms the idea that the mucin-like domain of α-dystroglycan needs to be extensively glycosylated in order to reach a stable conformation. The absence/reduction of glycosylation by itself may greatly reduce the stability of the dystroglycan complex. Although an altered pattern of α-dystroglycan O-mannosylation, that is not significantly changing its overall glycosylation fraction, represents the primary molecular clue behind currently known dystroglycanopathies, it cannot be ruled out that still unidentified forms of αDG-related dystrophy might originate by a more substantial reduction of α-dystroglycan glycosylation and by its consequent destabilization.

Dystroglycan is associated to the disulfide isomerase ERp57.

Dystroglycan (DG) is an extracellular receptor composed of two subunits, α-DG and ß-DG, connected through the α-DG C-terminal domain and the ß-DG N-terminal domain. We report an alanine scanning of all DG cysteine residues performed on DG-GFP constructs overexpressed in 293-Ebna cells, demonstrating that Cys-669 and Cys-713, both located within the ß-DG N-terminal domain, are key residues for the DG precursor cleavage and trafficking, but not for the interaction between the two DG subunits. In addition, we have used immunprecipitation and confocal microscopy showing that ERp57, a member of the disulfide isomerase family involved in glycoprotein folding, is associated and colocalizes immunohistochemically with ß-DG in the ER and at the plasma membrane of 293-Ebna cells. The ß-DG-ERp57 complex also included α-DG. DG mutants, unable to undergo the precursor cleavage, were still associated to ERp57. ß-DG and ERp57 were also co-immunoprecipitated in rat heart and kidney tissues. In vitro, a mutant ERp57, mimicking the reduced form of the wild-type protein, interacts directly with the recombinant N-terminal domain of both α-DG and ß-DG with apparent dissociation constant values in the micromolar range. ERp57 is likely to be involved in the DG processing/maturation pathway, but its association to the mature DG complex might also suggest some further functional role that needs to be investigated.

Cerebrospinal fluid top-down proteomics evidenced the potential biomarker role of LVV- and VV-hemorphin-7 in posterior cranial fossa pediatric brain tumors.

Posterior cranial fossa is the most frequent location of pediatric brain tumors. Its diagnosis is currently performed by postsurgery histopathology and the identification of biomarkers in cerebrospinal fluid (CSF) could provide a less invasive tool. Patient CSF was collected during surgery before the tumor removal (PRE-CSF) and 6 days after the resection (POST-CSF) and analyzed by top down LC-MS proteomics for comparison. The PRE-CSFs generally exhibited a less complex LC-MS profile than the relative POST-CSFs suggesting a suppressive role of the tumor toward proteins and peptides production or release. Particularly, a panel of peptides, identified as alpha- and beta-hemoglobin chains fragments, were generally absent in the PRE-CSF and present in the POST ones independently from contaminant blood hemoglobin. Among them, the LVV- and VV-hemorphin-7 showed the most repeatable trend and with a few remarkable exceptions: their unusual absence in POST surgery CSF was in fact interestingly correlated to the presence of tumor in the patient despite surgery due to metastases or to subtotal resection. These results ascribed a relevant biological role to LVV- and VV-h7 peptides in the disease and a strong potential as biomarkers. Their analysis in POST surgery CSF could be used to predict patient prognosis.

Glucose-6-phosphate dehydrogenase (G6PD) mutations database: review of the "old" and update of the new mutations.

In the present paper we have updated the G6PD mutations database, including all the last discovered G6PD genetic variants. We underline that the last database has been published by Vulliamy et al. [1] who analytically reported 140 G6PD mutations: along with Vulliamy's database, there are two main sites, such as http://202.120.189.88/mutdb/ and www.LOVD.nl/MR, where almost all G6PD mutations can be found. Compared to the previous mutation reports, in our paper we have included for each mutation some additional information, such as: the secondary structure and the enzyme 3D position involving by mutation, the creation or abolition of a restriction site (with the enzyme involved) and the conservation score associated with each amino acid position. The mutations reported in the present tab have been divided according to the gene's region involved (coding and non-coding) and mutations affecting the coding region in: single, multiple (at least with two bases involved) and deletion. We underline that for the listed mutations, reported in italic, literature doesn't provide all the biochemical or bio-molecular information or the research data. Finally, for the "old" mutations, we tried to verify features previously reported and, when subsequently modified, we updated the specific information using the latest literature data.

Enzymatic processing by MMP-2 and MMP-9 of wild-type and mutated mouse ß-dystroglycan.

Dystroglycan (DG) is a membrane-associated protein complex formed by two noncovalently linked subunits, α-DG, a highly glycosylated extracellular protein, and ß-DG, a transmembrane protein. The interface between the two DG subunits, which is crucial to maintain the integrity of the plasma membrane, involves the C-terminal domain of α-DG and the N-terminal extracellular domain of ß-DG. It is well known that under both, physiological and pathological conditions, gelatinases (i.e. MMP-9 and/or MMP-2) can degrade DG, disrupting the connection between the extracellular matrix and the cytoskeleton. However, the molecular mechanisms and the exact cleavage sites underlying these events are still largely unknown. In a previous study, we have characterized the enzymatic digestion of the murine ß-DG ectodomain by gelatinases, identifying a main cleavage site on the ß-DG ectodomain produced by MMP-9. In this article, we have deepened the pattern of the ß-DG ectodomain digestion by MMP-2 by using a combined approach based on SDS-PAGE, Orbitrap, and HPLC-ESI-IT mass spectrometry. Furthermore, we have characterized the kineticparameters of the digestion of some ß-DG ectodomain mutants by gelatinases.

Insertion of a myc-tag within α-dystroglycan domains improves its biochemical and microscopic detection.

BACKGROUND: Epitope tags and fluorescent fusion proteins have become indispensable molecular tools for studies in the fields of biochemistry and cell biology. The knowledge collected on the subdomain organization of the two subunits of the adhesion complex dystroglycan (DG) enabled us to insert the 10 amino acids myc-tag at different locations along the α-subunit, in order to better visualize and investigate the DG complex in eukaryotic cells. RESULTS: We have generated two forms of DG polypeptides via the insertion of the myc-tag 1) within a flexible loop (between a.a. 170 and 171) that separates two autonomous subdomains, and 2) within the C-terminal domain in position 500. Their analysis showed that double-tagging (the ß-subunit is linked to GFP) does not significantly interfere with the correct processing of the DG precursor (pre-DG) and confirmed that the α-DG N-terminal domain is processed in the cell before α-DG reaches its plasma membrane localization. In addition, myc insertion in position 500, right before the second Ig-like domain of α-DG, proved to be an efficient tool for the detection and pulling-down of glycosylated α-DG molecules targeted at the membrane. CONCLUSIONS: Further characterization of these and other myc-permissive site(s) will represent a valid support for the study of the maturation process of pre-DG and could result in the creation of a new class of intrinsic doubly-fluorescent DG molecules that would allow the monitoring of the two DG subunits, or of pre-DG, in cells without the need of antibodies.

Rapid detection of CFH (p.Y402H) and ARMS2 (p.A69S) polymorphisms in age-related macular degeneration using high-resolution melting analysis.

BACKGROUND: Age-related macular degeneration (AMD) is a complex disorder causing irreversible central vision loss. Complement Factor H (CFH) and age-related maculopathy susceptibility 2 (ARMS2) are now widely accepted as important AMD susceptibility genes. In particular, two specific variants, CFH p.Y402H and ARMS2 p.A69S, have been reported as strongly AMD associated. In order to perform the genetic screening of these single nucleotide polymorphisms (SNPs), we describe a high resolution melting analysis (HRM) as a rapid closed tube mutation scanning assay. METHODS: To validate HRM genotyping, 94 DNA samples from AMD patients (previously genotyped by sequence analysis) were analyzed. PCR amplification and melting curve analysis were performed in the LightCycler 480 Real-Time PCR System. In order to evaluate the accuracy of the HRM assay, we performed a blinded study of 20 unknown independent samples. RESULTS: We correctly genotyped all samples. In fact, all samples corresponded to the previous genotype assignments. CONCLUSIONS: Early identification of individuals with genetic risk variants CFH p.Y402H and ARMS2 p.A69S is clinically important for the definition of AMD status. High-resolution DNA melting is homogenous, accurate and rapid method for CFH and ARMS2 genotyping.

ß-amyloid decreases detectable endothelial nitric oxide synthase in human erythrocytes: a role for membrane acetylcholinesterase.

Until few years ago, many studies of Alzheimer's disease investigated the effects of this syndrome in the central nervous system. Only recently, the detection of amyloid beta peptide (Aß) in the blood has evidenced the necessity to extend studies on extraneuronal cells, particularly on erythrocytes. Aß is also present in brain capillaries, where it interacts with the erythrocytes, inducing several metabolic and functional alterations. Recently, functionally active endothelial type nitric oxide synthase (eNOS) was discovered in human erythrocytes. The goal of the present study was to evidence the effect of Aß on erythrocyte eNOS. We found that Aß following to 24-h exposure causes a decrease in the immune staining of erythrocyte eNOS. Concurrently, Aß alters erythrocyte cell morphology, decreases nitrites and nitrates levels, and affects membrane acetylcholinesterase activity. Propidium, an acetylcholinesterase inhibitor, was able to reverse the effects elicited by Aß. These events could contribute to the vascular alterations associated with Alzheimer's disease disease.

Anthracyclines and mitochondria.

Anthracyclines remain the cornerstone in the treatment of many malignancies including lymphomas, leukaemias, and sarcomas. Unfortunately, the clinical use of these potent chemotherapeutics is severely limited by the development of a progressive dose-dependent cardiomyopathy that irreversibly evolves toward congestive heart failure. The molecular mechanisms responsible for anthracycline anticancer activity as well as those underlying anthracycline-induced cardiotoxicity are incompletely understood and remain a matter of remarkable controversy. Anthracyclines have long been considered to induce cardiotoxicity by mechanisms different from those mediating their anticancer activity. In particular, anthracycline antitumor efficacy is associated with nuclear DNA intercalation, topoisomerase II inhibition and drug-DNA adducts formation, whereas the cardiotoxicity is prevalently ascribed to oxidative stress and mitochondrial dysfunction. At present, however, the view that distinct mechanisms are implied in anticancer and cardiotoxic responses to anthracycline therapy does not seem fully convincing since beneficial (anticancer) and detrimental (cardiotoxic) effects are to some extent overlapping, share the subcellular organelle targets, the molecular effectors and the pathophysiological processes (i.e. DNA strand breaks, oxidative stress, signalling pathways, mitochondrial dysfunctions, apoptosis etc.).Here, we review the potential role of mitochondria in the molecular mechanisms underlying anthracyclines anticancer activity as well as in the pathogenesis of anthracycline-induced cardiotoxicity.

Mitochondrial proteomic approaches for new potential diagnostic and prognostic biomarkers in cancer.

Mitochondrial dysfunction and mutations in mitochondrial DNA have been implicated in a wide variety of human diseases, including cancer. In recent years, considerable advances in genomic, proteomic and bioinformatic technologies have made it possible the analysis of mitochondrial proteome, leading to the identification of over 1,000 proteins which have been assigned unambiguously to mitochondria. Defining the mitochondrial proteome is a fundamental step for fully understanding the organelle functions as well as mechanisms underlying mitochondrial pathology. In fact, besides giving information on mitochondrial physiology, by characterizing all the components of this subcellular organelle, the application of proteomic technologies permitted now to study the proteins involved in many crucial properties in cell signaling, cell differentiation and cell death and, in particular, to identify mitochondrial proteins that are aberrantly expressed in cancer cells. An improved understanding of the mitochondrial proteome could be essential to shed light on the connection between mitochondrial dysfunction, deregulation of apoptosis and tumorigenesis and to discovery new therapeutic targets for mitochondria-related diseases.

Hemoglobin: Multiple molecular interactions and multiple functions. An example of energy optimization and global molecular organization.

One might think that after over 100 years of study we now know all there is to know about Hemoglobin and its function. However, the purpose of this review is to outline that this fascinating protein has still much to say in the field of biological modulation. Hence, we like to focus on a number of parallel functions of hemoglobin besides its basic function of oxygen transport. Among these we like to recall the following main functions: a) modulation of erythrocyte metabolism; b) Heme oxidation and erythrocytes senescence; c) resistance to malaria; d) molecular heat transducer e) Enzymatic activity; f) Hemorphins, carbon monoxide and nitric oxide.

Nucleophosmin C-terminal leukemia-associated domain interacts with G-rich quadruplex forming DNA.

Nucleophosmin (NPM1) is a nucleocytoplasmic shuttling phosphoprotein, mainly localized at nucleoli, that plays a key role in ribogenesis, centrosome duplication, and response to stress stimuli. Mutations at the C-terminal domain of NPM1 are the most frequent genetic lesion in acute myeloid leukemia and cause the aberrant and stable translocation of the protein in the cytoplasm. The NPM1 C-terminal domain was previously shown to bind nucleic acids. Here we further investigate the DNA binding properties of the NPM1 C-terminal domain both at the protein and nucleic acid levels; we investigate the domain boundaries and identify key residues for high affinity recognition. Furthermore, we demonstrate that the NPM1 C-terminal domain has a preference for G-quadruplex forming DNA regions and induces the formation of G-quadruplex structures in vitro. Finally we show that a specific sequence found at the SOD2 gene promoter, which was previously shown to be a target of NPM1 in vivo, is indeed folded as a G-quadruplex in vitro under physiological conditions. Our data extend considerably present knowledge on the DNA binding properties of NPM1 and suggest a general role in the transcription of genes characterized by the presence of G-quadruplex forming regions at their promoters.

Palytoxin induces functional changes of anion transport in red blood cells: metabolic impact.

Palytoxin (PTX) is classified as one of the most powerful marine biotoxins (of high molecular weight and no protein origin) because it is able to interact strongly with important cellular structures influencing their function in different biological processes. This study of the effects of PTX on red blood cells (RBC) extends the knowledge about its toxicity, which concerns not only the well-known action on Na(+)/K(+)-ATPase but also band 3 protein (B3 or AE1), the role of which is essential for anion transport and for the structure, function, and metabolic integrity of the erythrocyte. The effects of PTX on RBC can be summarized as follows: it alters the anionic flux and seriously compromises not only CO(2) transport but also the metabolic modulation centered on the oxy-deoxy cycle of hemoglobin; it stabilizes the plasma membrane by preventing lipid peroxidation; and its effect does not lead to activation of caspases 3 and 8. From what is reported in steps 2 and 3, and on the basis of the results obtained on hemolysis, methemoglobin levels, and phosphatase activity, an increase of the reducing power of the erythrocytes (RBC) in the presence of PTX clearly emerges. The results have enabled us to outline some metabolic adaptations induced in the RBC by PTX.

In vitro evaluation of the cytotoxicity of FotoSan™ light-activated disinfection on human fibroblasts.

BACKGROUND: Root canal disinfection needs to be improved because actual techniques are not able to eliminate all microorganisms present in the root canal system. The aim of the present study was to investigate the in vitro cytotoxicity of FotoSan (CMS Dental APS, Copenhagen Denmark), 17% EDTA and 2% chlorhexidine. MATERIAL/METHODS: Fibroblasts of periodontal ligament from healthy patients were cultured. FotoSan (with and without light activation for 30 sec.), 17% EDTA and 2% chlorexidine were used for the cell viability tests. Untreated cells were used as control. The cellular vitality was evaluated by MTT test. The production of reactive oxygen species (ROS) was measured using an oxidation-sensitive fluorescent probe. Results were statistically analyzed by ANOVA, followed by a multiple comparison of means by Student-Newman-Keuls, and the statistical significance was set at p<0.05. RESULTS: MTT tests showed that cytotoxic effects of FotoSan (both photocured and uncured) were statistically lower (p<0.05) than that observed using 2% Chlorhexidine, while no significant differences were found in comparison with 17% EDTA. No alterations in ROS production were detectable in any of the tested materials. CONCLUSIONS: Since the toxicity of the FotoSan photosensitizer, both light-activated and not light-activated, is similar to common endodontic irrigants, it can be clinically used with precautions of use similar to those usually recommended for the above-mentioned irrigating solutions.