Evaluation of the role of superoxide anions in endotoxin-induced impairment of beta-adrenoceptor-mediated vasodilation in equine digital veins

International audienceObjective: To investigate the role of superoxide anions in the lipopolysaccharide (LPS)-induced impairment of β-adrenoceptor-mediated equine digital vein (EDV) vasodilation.Sample Population:EDVs isolated from forelimbs of 24 healthy adult horses.Procedures: Endothelium-intact or endothelium-denuded EDV rings were incubated with or without LPS (10 μg/mL) of Escherichia coli (O55:B5) for 4 hours. Cumulative concentration-relaxation curves resulting from administration of isoprenaline, a nonselective β-adrenoceptor agonist, or from administration of SR 58611A, a selective β3-adrenoceptor agonist, were recorded in phenylephrine-preconstricted EDVs in the absence or the presence of superoxide dismutase (200 U/mL). Isoprenaline-induced relaxation was also evaluated with or without the cyclooxygenase inhibitors indomethacin (10μM) and NS-398 (10μM).Results: Isoprenaline and SR 58611A induced concentration-dependent relaxation of EDV rings, which was inhibited by LPS exposure. Superoxide dismutase abolished the inhibitory effect of LPS on the isoprenaline- and SR 58611A-mediated relaxation. Pretreatment of the LPS-treated EDVs with indomethacin or NS-398 restored the isoprenaline-mediated relaxation and abolished the LPS-induced impairment to a similar extent as superoxide dismutase.Conclusions and Clinical Relevance: Results supported a role of superoxide anions in the LPS-induced impairment of β-adrenoceptor-mediated EDV vasodilation. The LPS-induced oxidative stress in EDVs may contribute to vascular dysfunctions associated with laminitis in horses.</p

Carbon Nanotube Translocation to Distant Organs after Pulmonary Exposure: Insights from in Situ 14C-Radiolabeling and Tissue Radioimaging

International audienceFew approaches are available to investigate the potential of carbon nanotubes (CNTs) to translocate to distant organs following lung exposure, although this needs to be taken into account to evaluate potential CNT toxicity. Here, we report a method for quantitative analysis of the tissue biodistribution of multiwalled CNTs (MWCNTs) as a function of time. The method relies on the use of in situ 14C-radiolabeled MWCNTs and combines radioimaging of organ tissue sections to ex vivo analysis of MWCNTs by electron microscopy. To illustrate the usefulness of this approach, mice were exposed to a single dose of 20 μg of 14C-labeled MWCNTs by pharyngeal aspiration and were subjected to a follow-up study over one year. After administration, MWCNT were cleared from the lungs, but there was a concomitant relocation of these nanoparticles to distant organs starting throughout the follow-up period, with nanoparticle accumulation increasing with time. After one year, accumulation of MWCNTs was documented in several organs, including notably the white pulp of the spleen and the bone marrow. This study shows that the proposed method may be useful to complement other approaches to address unresolved toxicological issues associated with CNTs. These issues include their persistence over long periods in extrapulmonary organs, the relationship between the dose and the extent of translocation, and the effects of “safety by design” on those processes. The same approach could be used to study the translocation propensity of other nanoparticles containing carbon atoms

Combining efficient C-14-radiolabeling and radioimaging techniques of manufactured nanoparticles for toxicological studies

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Volatile Organic Compounds of Malignant Breast Cancer Wounds: Identification and Odors.

International audienceIntroduction. During the metabolic processes of malignant wounds, bacteria produce a large amount of volatile organic compounds (VOCs) that are responsible for malodors and may have a major impact on the patient's quality of life with a risk of isolation. Objective. A translational study was conducted on 32 malignant breast wounds by combining the identification of bacterial strains present on wounds, the identification of VOCs produced by these bacterial strains, and sensory evaluation to assess odor intensity and quality of odorous bacteria. Materials and Methods. Thirty-two patients with malignant breast cancer wounds > 10 cm(2) at various stages of the disease (curative or palliative) were included in the protocol. Volatile organic compounds were collected from primary dressings by headspace solid-phase microextraction and then analyzed by gas chromatography separation coupled with a mass spectrometer detector analysis. Microbiological samplings were taken and analyzed on agar plates. The odors of selected bacteria were assessed by a panel of staff members. Results. Proteus mirabilis and Fusobacterium necrophorum seem to produce the strongest and most typical malignant wound odor. The VOCs were analyzed and dimethyl disulfide, dimethyl trisulfide, phenol, indole, and 3-methylbutanal were found to be produced by bacteria generating the most typical wound odor. Conclusions. This study suggests the bacteria present in wounds may be responsible for odors. In addition, these findings could pave the way to engineer new types of dressings and to develop an evaluation method to assess their efficiency both quantitatively and qualitatively as well as improve quality of palliative care and comfort for women with malignant wounds

Screening of Breast Cancer from Sweat Samples Analyzed by 2-Dimensional Gas Chromatography-Mass Spectrometry: A Preliminary Study

Breast cancer (BC) remains one of the most commonly diagnosed malignancies in women. There is increasing interest in the development of non-invasive screening methods. Volatile organic compounds (VOCs) emitted through the metabolism of cancer cells are possible novel cancer biomarkers. This study aims to identify the existence of BC-specific VOCs in the sweat of BC patients. Sweat samples from the breast and hand area were collected from 21 BC participants before and after breast tumor ablation. Thermal desorption coupled with two-dimensional gas chromatography and mass spectrometry was used to analyze VOCs. A total of 761 volatiles from a homemade human odor library were screened on each chromatogram. From those 761 VOCs, a minimum of 77 VOCs were detected within the BC samples. Principal component analysis showed that VOCs differ between the pre- and post-surgery status of the BC patients. The Tree-based Pipeline Optimization Tool identified logistic regression as the best-performing machine learning model. Logistic regression modeling identified VOCs that distinguish the pre-and post-surgery state in BC patients on both the breast and hand area with sensitivities close to 1. Further, Shapley additive explanations and the probe variable method identified the most important and pertinent VOCs distinguishing pre- and post-operative status which are mostly of distinct origin for the hand and breast region. Results suggest the possibility to identify endogenous metabolites linked to BC, hence proposing this innovative pipeline as a stepstone to discovering potential BC biomarkers. Large-scale studies in a multi-centered VOC analysis setting must be carried out to validate obtained findings

Predictive Gene Signature of Response to the Anti-TweakR mAb PDL192 in Patient-Derived Breast Cancer Xenografts

<div><p>Purpose</p><p>(1) To determine TweakR expression in human breast cancers (BC), (2) evaluate the antitumor effect of the anti-TweakR antibody PDL192, used alone or after chemotherapy-induced complete remission (CR), on patient-derived BC xenografts (PDX) and (3) define predictive markers of response.</p><p>Experimental Design</p><p>TweakR expression was analyzed by IHC on patients and PDXs BC samples. <i>In vivo</i> antitumor effect of PDL192 was evaluated on eight TweakR-positive BC PDXs alone or after complete remission induced by a combination of doxorubicin and cyclophosphamide. Using both responding and resistant PDX tumors after PDL192 administration, RT-QPCR were performed on a wide list of selected candidate genes to identify predictive markers of response.</p><p>Results</p><p>TweakR protein was expressed in about half of human BC samples. <i>In vivo</i> PDL192 treatment had significantly anti-tumor activity in 4 of 8 TweakR-positive BC PDXs, but no correlation between the expression level of the Tweak receptor and response to therapy was observed. PDL192 also significantly delayed tumor relapse after CR. Finally, an 8 gene signature was defined from sensitive and resistant PDXs.</p><p>Conclusions</p><p>PDL192 was highly efficient in some BC PDXs. We found 8 genes that were differentially expressed in responding and resistant tumors and could constitute a gene expression signature which would need to be extended to other xenograft models for confirmation. These data confirm the therapeutic potential of TweakR targeting in BC and the possibility of prospectively selecting patients who might benefit from therapy.</p></div

Correlation between TweakR expression and biological and clinical characteristics of the 134 included breast cancer patients.

<p>Pathol. tumor size, pathological tumor size; the mitotic index (MI) was calculated as a percentage as follows: the number of dividing cells divided by the total number of cells present in ten cellular fields (x400).</p><p>Correlation between TweakR expression and biological and clinical characteristics of the 134 included breast cancer patients.</p

TweakR staining H-score distributions in the overall patient’s tumors (A), in patient’s tumors according to their breast cancer sub-groups (B) and in xenografts (C).

<p>H-score was calculated as <i>H-score = epithelial cell staining percentage×staining intensity</i>.</p