Toxicological Aspects of the Essential Oil from Cinnamodendron dinisii

The objective of this study was to determine cytotoxic activity, hemolytic activity, and to evaluate the ability of the essential oil from Cinnamodendron dinisii to induce DNA fragmentation of human lymphocytes. The essential oil was obtained by hydrodistillation. Cytotoxic activity was determined by the MTT method. Hemolytic activity was evaluated by spectrophotometric quantification of hemoglobin released by erythrocytes. Damage to lymphocyte DNA molecules was assessed by the Comet assay. The essential oil under study showed high cytotoxic activity on Vero cells (CC₅₀ = 35.72 μg/mL) and induced hemolysis in both hematocrits, besides leading to the oxidation of hemoglobin released. The genotoxic activity of C. dinisii essential oil was also observed, which induced concentration‐dependent DNA fragmentation of human lymphocytes and, at 50 μL/mL, it was more active than the positive control. The essential oil from C. dinisii has a toxic action, suggesting a special attention in the application of this oil to health‐promoting activities; however, among its components, there are molecules with potential for future application in anticancer therapies.     

High prevalence of latent tuberculosis infection in autoimmune disorders such as psoriasis and in chronic respiratory diseases, including lung cancer

The early diagnosis and treatment of individuals harboring M. tuberculosis is key to ensuring the effectiveness of health programs aimed at the elimination of tuberculosis (TB). Monitoring for TB also has other important health care implications for the related immune pathology caused by the chronic inflammatory response to M. tuberculosis. Moreover, the recent introduction of biologic therapies for the treatment of several immune-mediated inflammatory diseases has shown unexpected high frequencies of reactivation of latent TB. The present cross-sectional study is aimed at estimating the prevalence of latent tuberculosis infection (LTBI) in different groups of subjects, either undergoing a routine program of screening for TB or a clinical monitoring of autoimmune or lung disorders, by analyzing their immune response in vitro to a pool of different M. tuberculosis antigens through an IFN-gamma-release assay (IGRA). We consecutively tested 1,644 subjects including health care workers (931), healthy immigrants from different countries (93), patients with a diagnosis of psoriasis (405), patients with lung inflammatory disease (60) or lung neoplasia (32) and a group of HIV-1 infected Italian subjects (120). The prevalence of IGRAs positive responses among health care workers was 8.9 percent. In comparison, significantly higher frequencies were found in healthy immigrant subjects (33.3%), similar to those found in inflammatory broncho-pneumopathies (34.5%) or lung cancer (29.6%). Interestingly, an unexpected high prevalence was also found in patients affected by psoriasis (18.0%), while HIV-infected subjects had values comparable to those of health care workers (10.8%). An age cut-off was determined and applied for each group by receiver operating characteristic (ROC) curves in order to perform the statistical analysis among age-comparable groups. Multivariate analysis showed that the age and clinical conditions such as having a diagnosis of psoriasis or a lung inflammatory disease were independent risk factors for developing an IGRA positive response. This study highlights an unprecedented high prevalence of IGRA positive responses among patients affected by psoriasis and emphasizes the need for a preliminary assessment of LTBI before the administration of any biologic therapy based on cytokine antagonists such as anti-TNF-alpha. Moreover, screening for LTBI should be routinely performed in the presence of a chronic pulmonary disease.     

Ten Years of Global Evolution of the Human Respiratory Syncytial Virus BA Genotype with a 60-Nucleotide Duplication in the G Protein Gene

The emergence of natural isolates of human respiratory syncytial virus group B (HRSV-B) with a 60-nucleotide (nt) duplication in the G protein gene in Buenos Aires, Argentina, in 1999 (A. Trento et al., J. Gen. Virol. 84:3115-3120, 2003) and their dissemination worldwide allowed us to use the duplicated segment as a natural tag to examine in detail the evolution of HRSV during propagation in its natural host. Viruses with the duplicated segment were all clustered in a new genotype, named BA (A. Trento et al., J. Virol. 80:975-984, 2006). To obtain information about the prevalence of these viruses in Spain, we tested for the presence of the duplicated segment in positive HRSV-B clinical samples collected at the Severo Ochoa Hospital (Madrid) during 12 consecutive epidemics (1996-1997 to 2007-2008). Viruses with the 60-nt duplication were found in 61 samples, with a high prevalence relative to the rest of B genotypes in the most recent seasons. Global phylogenetic and demographic analysis of all G sequences containing the duplication, collected across five continents up until April 2009, revealed that the prevalence of the BA genotype increased gradually until 2004-2005, despite its rapid dissemination worldwide. After that date and coinciding with a bottleneck effect on the population size, a relatively new BA lineage (BA-IV) replaced all other group B viruses, suggesting further adaptation of the BA genotype to its natural host.Human respiratory syncytial virus (HRSV), a member of the Pneumovirus genus within the Paramyxoviridae family, is recognized as the leading agent responsible for severe respiratory infections in the pediatric population (31, 34, 35) and a pathogen of considerable importance in vulnerable adults (23, 24). The global respiratory syncytial virus (RSV) disease burden is estimated at 64 million cases and 160,000 deaths every year (70). This virus causes regular seasonal epidemics which take place during the winter months in temperate countries or during the rainy season in tropical areas (12). A peculiar aspect of HRSV is that the immune response produced by infection does not confer long-lasting protection, which is why reinfections are common throughout life (30).Neutralization tests performed with hyperimmune serum (16) and reactivity with specific monoclonal antibodies (4, 45) were used to classify HRSV isolates into two antigenic groups, A and B, which correlated with genetically distinct viruses (18). The main differences between these two groups are located in the major attachment G protein. This protein is a type II glycoprotein that shares neither sequence nor structural features with the attachment proteins (HN or H) of other paramyxoviruses (69), and it represents one of the targets of the immune response (27, 43). The full-length membrane-bound G protein (Gm) of 292 to 319 amino acids (depending on the viral strain) is also expressed in a secreted version (Gs) that lacks the transmembrane domain due to alternative initiation of translation at a second in-frame AUG codon in the G open reading frame (M48) (52). The G protein is the viral gene product with the highest degree of antigenic and genetic diversity among viral isolates (4, 18, 28, 45). Most changes are concentrated in two hypervariable regions that flank a highly conserved central region of the G protein ectodomain, which includes a cluster of four cysteines and the putative receptor binding site (43). It has been suggested that antigenic differences within this protein could facilitate repeated HRSV infections (37, 59). In addition, positive selection of amino acid changes was observed in the two hypervariable regions of the G protein ectodomain (7, 43, 71, 73, 74). One of the hypervariable regions, located in the C-terminal one-third of the G molecule, contains multiple epitopes recognized by monoclonal antibodies (43), suggesting that immune selection of new variants by antibodies may contribute to generation of HRSV diversity.Phylogenetic studies based on sequence analysis of the G protein have identified numerous genotypes in the antigenic groups A and B that show complex circulation patterns, since multiple genotypes of both antigenic groups may circulate within the same season and community, with one or two dominant genotypes being replaced in successive years (13, 14, 26, 27, 32, 49, 50). Each community shows a seasonal circulation pattern of genotypes, probably determined by local factors, such as the level of herd immunity to certain strains (3, 14, 49).The capacity of the G protein to accommodate drastic sequence changes was illustrated best by three antigenic group B viruses isolated in Buenos Aires, Argentina, in 1999 that contained a duplication of 60 nucleotides (nt) in the C-terminal third of the G protein gene (63). The global dissemination of these viruses allowed us to use the duplicated segment as a natural tag to reexamine the evolution of HRSV during propagation in its natural host. Phylogenetic analysis of G sequences revealed that all viruses with the duplicated segment clustered in a new genotype, named BA, and this finding supported the idea of a common ancestor for all viruses with the 60-nt duplication, dated about 1998 (64). The limited information about the molecular epidemiology of HRSV in Spain, together with an increase in G sequences with the duplicated segment reported worldwide, prompted us to conduct both a local search in Madrid for these viruses and a global phylogenetic analysis of HRSV with the 60-nt duplication from the time that these viruses were first detected, taking into account the geographic and temporal distribution of each isolate.     

Anti-intercellular substance antibody log titres are correlated with serum concentrations of interleukin-6, interleukin-15 and tumor necrosis factor-alpha in patients with Pemphigus vulgaris relationships with peripheral blood neutrophil counts, disease severity and duration and patients' age

Pemphigus vulgaris is a rare dermatosis of autoimmune origin, characterized by autoantibodies directed against intercellular substance (AICS) and presenting with intra-epidermal blisters and/or erosions of the skin and mucous membranes. The aim of this paper is to analyze the relationships between serum AICS titers (after log transformation) and: patients' age, disease duration and disease activity; serum cytokine (IL-6, IL-7, IL-15 and TNF-alpha) concentrations and peripheral blood cell counts (namely neutrophils, lymphocytes and natural killer cells). Fifteen consecutive subjects affected with PV were enrolled. Diagnosis was supported by histological examination as well as by direct and indirect immunofluorescence tests. Cytokine determinations were made by means of commercially available ELISA kits. This study shows for the first time that AICS titers have a significant correlation with age of PV patients (R=0.57, p=0.031) and with the disease duration (R=0.73, p=0.002). A correlation between blood neutrophils count and log (AICS) titres was observed (R=0.6, p=0.021). Furthermore, significant correlations were observed between log (AICS) titres and serum IL-15 (R=0.54, p=0.048), serum IL-6 (R=0.53, p=0.05) or serum TNF-alpha concentrations (R=0.53, p=0.05). These data, taken together, show that there are several connections between the log (AICS) titres, some proinflammatory cytokines, peripheral blood neutrophil counts and the numbers of individuals' lesions, suggesting a relationship between AICS production and lesion development.     

Natural history of human respiratory syncytial virus inferred from phylogenetic analysis of the attachment (G) glycoprotein with a 60-nucleotide duplication

A total of 47 clinical samples were identified during an active surveillance program of respiratory infections in Buenos Aires (BA) (1999 to 2004) that contained sequences of human respiratory syncytial virus (HRSV) with a 60-nucleotide duplication in the attachment (G) protein gene. This duplication was analogous to that previously described for other three viruses also isolated in Buenos Aires in 1999 (A. Trento et al., J. Gen. Virol. 84:3115-3120, 2003). Phylogenetic analysis indicated that BA sequences with that duplication shared a common ancestor (dated about 1998) with other HRSV G sequences reported worldwide after 1999. The duplicated nucleotide sequence was an exact copy of the preceding 60 nucleotides in early viruses, but both copies of the duplicated segment accumulated nucleotide substitutions in more recent viruses at a rate apparently higher than in other regions of the G protein gene. The evolution of the viruses with the duplicated G segment apparently followed the overall evolutionary pattern previously described for HRSV, and this genotype has replaced other prevailing antigenic group B genotypes in Buenos Aires and other places. Thus, the duplicated segment represents a natural tag that can be used to track the dissemination and evolution of HRSV in an unprecedented setting. We have taken advantage of this situation to reexamine the molecular epidemiology of HRSV and to explore the natural history of this important human pathogen.     

Molecular interactions between p-coumaric acid and snake venom toxins

A large number of natural compounds, such as phenolic compounds, have been scientifically evaluated in the search for enzyme inhibitors. The interactions between the phenolic compound p-coumaric acid and the enzymes present in snake venoms (used as research tools) were evaluated in vitro and in silico. The p-coumaric acid was able to inhibit 31% of the phospholipase activity induced by Bothrops alternatus venom, 27% of the hemolytic activity induced by B. moojeni, 62.5% of the thrombolytic activity induced by B. jararacussu, and approximately 27% of the activity thrombosis induced by Crotalus durissus terrificus. Previous incubation of p-coumaric acid with the venoms of B. atrox and B. jararacussu increased the coagulation time by 2.18 and 2.16-fold, respectively. The activity of serine proteases in B. atrox and B. jararacussu venoms was reduced by 60% and 66.34%, respectively. Computational chemistry analyses suggests the specific binding of p-coumaric acid to the active site of proteases through hydrogen and hydrophobic interactions. The phenolic compound evaluated in this work has great potential in therapeutic use to both prevent and treat hemostatic alterations, because the venom proteins inhibited by the p-coumaric acid have high homology with human proteins that have a fundamental role in several pathologies.     

The protective effect exerted by ascorbic acid on DNA fragmentation of human leukocytes induced by Lachesis muta muta venom

The objective of this study was to evaluate the genotoxic and mutagenic effects of the toxins present in Lachesis muta muta's venom on human peripheral blood leukocytes and the protective potential of ascorbic acid on DNA fragmentation. The venom of L. muta muta was incubated in different concentrations (1, 2.5, 5, 7.5, 10, 15, 20, 30, 40, 50, 60, and 120 µg/mL) with human blood to evaluate DNA fragmentation using the comet, agarose gel electrophoresis, and micronucleus assays. In these concentrations evaluated, the venom of L. muta muta induced genotoxicity (comet assay and agarose gel electrophoresis) and mutagenicity (micronucleus test), but they were not cytotoxic, as they did not change the rate of cell proliferation after cytokinesis blockade with cytochalasin B. The ascorbic acid significantly inhibited the genotoxicity induced by L. muta muta venom in the proportions evaluated (1:0.1 and 1:0.5, venom/ascorbic acid - w/w). Thus, future studies are needed to elucidate the protective mechanisms of ascorbic acid on the genotoxic effects induced by toxins present in snake venoms.