Intracranial Hemorrhage from Dural Arteriovenous Fistulas: What Can We Find with CT Angiography?

Background: Dural arteriovenous fistulas (DAVF) represent a rare acquired intracranial vascular malformation, with a variety of clinical signs and symptoms, which make their diagnosis difficult. Intracranial hemorrhage is one of the most serious clinical manifestations. In this paper the authors’ goal was to verify the accuracy and utility of contrast-enhanced brain CT angiography (CTA) for the identification and the characterization of dural arteriovenous fistulas (DAVFs) in patients who presented with brain hemorrhage compared to 3D digital subtraction angiography (3D DSA); (2) a retrospective study of 26 patients with DAVFs who presented with intracranial hemorrhage to our institution was performed. The information reviewed included clinical presentation, location and size of hemorrhage, brain CTA and 3D DSA findings; (3) results: 61% (16/26) of DAVFs were identified by CTA. The vast majority of patients were male (69%, 18/26) and the most common presenting symptom was sudden onset headache. All DAVFs had cortical venous drainage and about one-third were associated with a venous varix. The most common location was tentorial (73%, 19/26); (4) conclusions: CTA can represent a valid alternative diagnostic method to 3D DSA for the study of DAVF in the initial and preliminary diagnostic approach, especially in emergency situations. In fact, it represents a fast, inexpensive, non-invasive and above all, easily accessible and available diagnostic technique, unlike DSA or MRI, allowing to provide information necessary for the identification, classification and treatment planning of DAVF

Etude du comportement de lactobacillus sakei dans le tractus digestif de souris conventionelles et axéniques

Bien que typique du milieu carné, Lactobacillus sakei a été détecté dans les fèces humaines en utilisant des méthodes culturales et moléculaires. L. sakei est aussi utilisé dans les processus de fermentations industrielles de certains produits carnés et végétaux qui pourrait expliquer sa présence dans les fèces humaines. L objectif de cette thèse était d étudier le comportement de L. sakei dans le tractus digestif (TD) en utilisant des souris conventionnelles et axéniques comme modèle. Une souche de L. sakei, nommée FLEC01, a été isolée à partir d échantillons fécaux humains et comparée à une autre souche humaine (L. sakei LTH5590) et à la souche L. sakei 23K, isolée de saucisson. Les trois souches ont des caractéristiques génomiques similaires, elles survivent sans s implanter dans l intestin des souris conventionnelles et elles colonisent le TD des souris axéniques. Les trois souches mises en compétition dans le TD de souris axéniques ont été détectées au même niveau pendant plusieurs jours par une méthode de PCR quantitative permettant de distinguer les trois souches. Cette méthode a été appliquée à des échantillons fécaux humains. Nous avons montré que L. sakei peut être présent à des taux de 107 g de fèces dans certains sujets et que des souches différentes sont retrouvées entre sujets. Le transit dans le TD des souris axéniques mène à l apparition et à l implantation de souches mutantes de L. sakei qui ont une morphologie de colonie petite (S) ou rugueuse (R) et une forme de cellule modifiée. La comparaison des protéomes de L. sakei 23K et d un clone rugueux R dérivé de celle ci a permis d identifier des différences qui pourraient expliquer la meilleure adaptation de ce clone au TD : modifications i) de la réponse aux stress ; ii) du métabolisme carboné et iii) de la forme des cellules résultant de la surexpression de la protéine MreBAlthough typical of the meat environment, Lactobacillus sakei has been detected in human feces using cultural and molecular methods. As L. sakei is also used in industrial fermentation of meat and vegetal products, its presence in the human feces may be of food origin. The aim of this thesis was to investigate the behavior of L. sakei in the gastrointestinal tract (GIT) of conventional and axenic mice by evaluating its colonization ability and analyzing its strategy adopted for either potential establishment or survival in the GIT. One L. sakei strain, named FLEC01, was isolated from human fecal samples and compared to another human isolate (L. sakei LTH5590) and to the meat strain L. sakei 23K. The three strains have similar genomic characteristics and they behave in the same way in the GIT of mice: they transit without persisting through the GIT of conventional mice and they can colonize the GIT of axenic mice. In addition, when axenic mice were fed with a mixed culture of the three strains, none of them was able to outnumber the others. We developed a quantitative PCR method allowing us to discriminate these different strains. The presence of L. sakei strains in human fecal samples was detected and quantified by this method. We found that L. sakei can be present at 107 g of feces in some subjects and that different strains should exist between the subjects. The transit in the GIT of axenic mice led to the appearance and the establishment of L. sakei mutants exhibiting small (S) or rough (R) colony morphology and modified cell shape. By comparing the proteomes of L. sakei 23K and one of its derivative R clones, differences which could explain the better adaptation of the R clone to the GIT environment were identified in modification of i) stress response; ii) carbon metabolism and iii) cell shape due to overexpression of MreB.ORSAY-PARIS 11-BU Sciences (914712101) / SudocSudocFranceF

Behavior of the Meat-Borne Bacterium Lactobacillus sakei during Its Transit through the Gastrointestinal Tracts of Axenic and Conventional Mice ▿ †

A Lactobacillus sakei strain named FLEC01 was isolated from human feces and characterized genotypically. Comparison of the genetic features of this strain with those of both the meat-borne L. sakei strain 23K and another human isolate, LTH5590, showed that they belong to different but closely related clusters. The three L. sakei strains did not persist and only transited through the gastrointestinal tracts (GITs) of conventional C3H/HeN mice. In contrast, they all colonized the GITs of axenic mice and rapidly reached a population of 109 CFU/g of feces, which remained stable until day 51. Five days after mice were fed, a first subpopulation, characterized by small colonies, appeared and reached 50% of the total L. sakei population in mice. Fifteen to 21 days after feeding, a second subpopulation, characterized by rough colonies, appeared. It coexisted with the two other populations until day 51, and its cell shapes were also affected, suggesting a dysfunction of the cell division or cell wall. No clear difference between the behaviors of the meat-borne strain and the two human isolates in both conventional and axenic mice was observed, suggesting that L. sakei is a food-borne bacterium rather than a commensal one and that its presence in human feces originates from diet. Previous observations of Escherichia coli strains suggest that the mouse GIT environment could induce mutations to increase their survival and colonization capacities. Here, we observed similar mutations concerning a food-grade gram-positive bacterium for the first time

Analysis of Lactobacillus sakei Mutants Selected after Adaptation to the Gastrointestinal Tracts of Axenic Mice▿ †

We recently showed that Lactobacillus sakei, a natural meat-borne lactic acid bacterium, can colonize the gastrointestinal tracts (GIT) of axenic mice but that this colonization in the intestinal environment selects L. sakei mutants showing modified colony morphology (small and rough) and cell shape, most probably resulting from the accumulation of various mutations that confer a selective advantage for persistence in the GIT. In the present study, we analyzed such clones, issued from three different L. sakei strains, in order to determine which functions were modified in the mutants. In the elongated filamentous cells of the rough clones, transmission electron microscopy (TEM) analysis showed a septation defect and dotted and slanted black bands, suggesting the presence of a helical structure around the cells. Comparison of the cytoplasmic and cell wall/membrane proteomes of the meat isolate L. sakei 23K and of one of its rough derivatives revealed a modified expression for 38 spots. The expression of six oxidoreductases, several stress proteins, and four ABC transporters was strongly reduced in the GIT-adapted strain, while the actin-like MreB protein responsible for cell shaping was upregulated. In addition, the expression of several enzymes involved in carbohydrate metabolism was modified, which may correlate with the observation of modified growth of mutants on various carbon sources. These results suggest that the modifications leading to a better adaptation to the GIT are pleiotropic and are characterized in a rough mutant by a different stress status, a cell wall modification, and modified use of energy sources, leading to an improved fitness for the colonization of the GIT

Identification of New Antimicrobial Peptides from Mediterranean Medical Plant Charybdis pancration (Steinh.) Speta

The present work was designed to identify and characterize novel antimicrobial peptides (AMPs) from Charybdis pancration (Steinh.) Speta, previously named Urginea maritima, is a Mediterranean plant, well-known for its biological properties in traditional medicine. Polypeptide-enriched extracts from different parts of the plant (roots, leaves and bulb), never studied before, were tested against two relevant pathogens, Staphylococcus aureus and Pseudomonas aeruginosa. With the aim of identifying novel natural AMPs, peptide fraction displaying antimicrobial activity (the bulb) that showed minimum inhibitory concentration (MICs) equal to 30 µg/mL against the above mentioned strains, was analysed by high-resolution mass spectrometry and database search. Seventeen peptides, related to seven proteins present in the investigated database, were described. Furthermore, we focused on three peptides, which due to their net positive charge, have a better chance to be AMPs and they were investigated by molecular modelling approaches, in order to shed light on the solution properties of their equilibrium structures. Some of new detected peptides could represent a good platform for the development of new antimicrobials in the fight against antibiotic resistance phenomenon

Transcriptional Alterations of ET-1 Axis and DNA Damage in Lung Tissue of a Rat Obesity Model

Obesity has been implicated in the development of many cancers. This can lead to genome damage, especially in the form of double-strand break, the presence of which is now easily detected through nuclear phosphorylation of histone H2AX (γ-H2AX) focus assay. Recently, the endothelin (ET) axis has also been shown to have a role in the growth and progression of several tumors, including lung cancer. The aim of this study was to evaluate the ET-1 system transcriptional alterations and γ-H2AX in lung tissue of Zucker rats subdivided into obese (O, n=22) and controls (CO, n=18) rats: under either fasting conditions (CO(fc)-O(fc)) or acute hyperglycemia (CO(AH)-O(AH)). Significantly higher prepro-ET-1 (p=0.05) and ET-converting enzyme (ECE)-2 mRNA expression was observed in O with respect to CO. A significant positive association was observed between prepro-ET-1 and ET-A in the whole rat population (p=0.009) or in the obese group alone (p=0.007). The levels of γ-H2AX in O and in O(AH) rats were significantly higher (p=0.019) than in the corresponding CO and CO(AH) rats (p=0.038). The study shows an inappropriate secretion of ET-1 in O animals with a parallel DNA damage in their lungs, providing novel mechanisms by which ET receptor antagonist may exert organ protection

Gene and Protein Expression in Response to Different Growth Temperatures and Oxygen Availability in <i>Burkholderia thailandensis</i>

<div><p><i>Burkholderia thailandensis</i>, although normally avirulent for mammals, can infect macrophages <i>in vitro</i> and has occasionally been reported to cause pneumonia in humans. It is therefore used as a model organism for the human pathogen <i>B. pseudomallei</i>, to which it is closely related phylogenetically. We characterized the <i>B. thailandensis</i> clinical isolate CDC2721121 (BtCDC272) at the genome level and studied its response to environmental cues associated with human host colonization, namely, temperature and oxygen limitation. Effects of the different growth conditions on BtCDC272 were studied through whole genome transcription studies and analysis of proteins associated with the bacterial cell surface. We found that growth at 37°C, compared to 28°C, negatively affected cell motility and flagella production through a mechanism involving regulation of the flagellin-encoding <i>fliC</i> gene at the mRNA stability level. Growth in oxygen-limiting conditions, in contrast, stimulated various processes linked to virulence, such as lipopolysaccharide production and expression of genes encoding protein secretion systems. Consistent with these observations, BtCDC272 grown in oxygen limitation was more resistant to phagocytosis and strongly induced the production of inflammatory cytokines from murine macrophages. Our results suggest that, while temperature sensing is important for regulation of <i>B. thailandensis</i> cell motility, oxygen limitation has a deeper impact on its physiology and constitutes a crucial environmental signal for the production of virulence factors.</p></div

EPS/LPS determination.

<p><b>A</b>) Quantitative determination of cell surface-associated polysaccharides using the phenol/sulfuric acid method. Values are the average of six measurements (two repeats for three independent cultures) and standard deviations are shown. Statistical analysis (two-tailed Student’s t test) of the results provided a p value<0.0001 (indicated by the three asterisks in the figure). <b>B</b>) PAGE analysis of cell surface-associated polysaccharides. The main band detected by silver staining, is indicated by the arrow. PAGE analysis of cell surface-associated polysaccharides from three independent BtCDC272 cultures gave very similar results.</p

<i>In vitro</i> phagocytosis of BtCDC272 grown in different conditions by neutrophils in whole blood.

<p><i>In vitro</i> phagocytosis of BtCDC (10 and 100 M.O.I) by human neutrophils of two donors was determined by FACS analysis at 15 min. Data are expressed as the percentage of control MFI. The mean value ± SEM is shown. *<i>p</i>≤0.05; **<i>p</i>≤0.01; ***<i>p</i>≤0.001; two-tailed Student’s <i>t</i> test. 0. Results for each donor, expressed as MFI, are shown in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0093009#pone.0093009.s003" target="_blank">Figure S3</a>.</p

Cytokine production by mouse macrophage cell line RAW264.7 exposed to BtCDC272 grown in different conditions and at different M.O.I.

<p>Confluent monolayers of cells were incubated with bacteria cultured at the indicated conditions. Bacteria were added at MOI of 0.005, 0.05, 0.5 or 5 for 4 hours to confluent monolayers of RAW264.7 cells. LPS (100 ng/ml from <i>E. coli</i> Serotype 055:B5; Sigma-Aldrich) was used as positive control of macrophage activation. Murine CXCL2, TNF-α and IL-6 levels were measured in cell supernatants by ELISA Results are mean± SEM of two independent experiments.</p