BACKGROUND Local application of fluorouracil (Efudix, 5-FU) induces sclerosis in patients with sinonasal tumors and superficial basocellular skin carcinoma. As a 'back against the wall' treatment, we investigated the local effect of nasally applied 5-FU and whether this could decrease the burden of severe epistaxis in patients with hereditary hemorrhagic telangiectasia (HHT). METHODS HHT patients with severe and frequent epistaxis, subsequent anemia and a necessity for blood and/or iron infusions were treated with a nasal tampon with 5-FU. This tampon was placed unilaterally in the nasal cavity on the side of the most severe epistaxis and replaced once weekly during 4 weeks. Outcome measures were safety and side effects, the aspect of the nasal mucosa measured with the mucosal HHT score, the epistaxis severity score (ESS), hemoglobin and ferritin plasma levels, and quality of life assessment pre-treatment, one and three months post-treatment. RESULTS Six HHT patients participated. During treatment and follow-up, the nasal mucosa turned more pale and sclerotic and the number of telangiectases diminished. The mucosal HHT score improved and the ESS declined (p = 0.01). The decline of ESS persisted up to 3 months post-5-FU treatment. Moreover, mean hemoglobin levels increased from 6.0 pre-5-FU to 6.8 after one month post-5-FU. CONCLUSION Unilateral application of 5-FU on a nasal tampon diminished the severity and frequency of epistaxis in all HHT patients. This effect sustained up to three months post-treatment, despite the fact that the contralateral side remained untreated. Subsequently, hemoglobin levels increased. Intranasal 5-FU is a promising entity for further research on epistaxis treatment in HHT patients.BACKGROUND TMEM100 is identified as a downstream gene of bone morphogenetic protein 9 (BMP9) signaling via activin receptor-like kinase 1 (ALK1), which is known to participate in lymphangiogenesis as well as angiogenesis. TMEM100 has been shown to be important for blood vessel formation and maintenance, but its role in the development of lymphatic vasculature remains unknown. The objective is to investigate the role of TMEM100 in development of the lymphatic system. METHODS AND RESULTS Global Tmem100 gene deletion was induced by tamoxifen on 10.5 days post-coitus. Tmem100-inducible knockout (iKO) embryos in embryonic days (E)14.5-16.5 exhibited edema and blood-filled enlarged lymphatics with misconnections between veins and lymphatic vessels. For a reciprocal approach, we have generated a novel mouse line in which TMEM100 overexpression (OE) can be induced in endothelial cells by intercrossing with Tie2-Cre driver. TMEM100-OE embryos at E12.5-14.5 exhibited edema with small size and number of lymphatic vessels, the exact opposite phenotypes of Tmem100-iKOs. In Tmem100-iKO embryos, the number of progenitors of lymphatic endothelial cells (LECs) in the cardinal vein was increased, while it was decreased in TMEM100-OE embryos. The activity of NOTCH signaling, which limits the number of progenitors of LECs in the cardinal vein, was decreased in Tmem100-iKO embryos, whereas it was increased in TMEM100-OE embryos. CONCLUSION TMEM100 plays an important role in the specification of LECs in the cardinal veins, at least in part, by regulating the NOTCH signaling.BACKGROUND Glucocorticoid (GC) insensitivity is an important feature of severe and fatal asthma. Oxidative stress can induce phosphoinositide-3-kinase (PI3K) activation, contributing to the development of GC insensitivity in chronic airway diseases. However, the underlying molecular mechanism of PI3K in the pathogenesis of severe asthma remains unknown. METHODS We isolated peripheral blood mononuclear cells (PBMCs) from 34 participants (12 patients with mild/moderate asthma, 10 patients with severe asthma, and 12 control subjects). H2O2 was used to stimulate the human macrophage line U937 to mimic the oxidative stress status in severe asthma. The ability of candidate compounds, namely, azithromycin, PI3K inhibitors (BEZ235 and LY294002) and a p38 MAPK inhibitor (BIRB796), to ameliorate GC insensitivity in severe asthma was evaluated. RESULTS PBMCs from patients with severe asthma exhibited dose-dependent and time-dependent GC insensitivity, which correlated with reduced activity of histone deacetylase 2 (HDAC2) (p  less then  0.05) and elevated expression of proinflammatory genes [nuclear factor-κB (NF-κB) and activator protein-1 (AP-1)] (p  less then  0.01) compared with these parameters in the control group. The PI3K inhibitors (BZE235 and LY294002) significantly restored the GC sensitivity of PBMCs from patients with severe asthma. In vitro, the PI3K inhibitors (BZE235 and LY294002) ameliorated GC insensitivity in H2O2/TNFα-induced IL-8 release from U937 cells by independently restoring the activity of HDAC2 or inhibiting the activation of transcription factors. CONCLUSIONS This study demonstrates that PI3K inhibitors ameliorate GC insensitivity in severe asthma by restoring HDAC2 activity and inhibiting the phosphorylation of nuclear signaling transcription factors.OBJECTIVES Most attention has been focused on physiologically generated membrane blebs on the cellular cortex, whereas artificial membrane blebs induced by chemicals are studied to a lesser extent. RESULTS We found that exposure of HeLa human cervical cancer cells to paraformaldehyde (PFA), followed by incubation in phosphate-buffered saline (PBS) efficiently induced large membrane blebs on the cellular cortex.  https://www.selleckchem.com/products/Temsirolimus.html  Intriguingly, sequential exposure of the PFA-treated cells to PBS containing dimethyl sulfoxide (DMSO) facilitated shedding of the blebs from the cellular cortex, yielding a high quantity of large extracellular vesicles in the supernatant, which was applicable to assess the potentials of compounds and proteins as membrane influencers. Similar effects of PFA and DMSO were detected on the cellular cortex of other human, mouse, and fish cells. CONCLUSIONS Our procedure to facilitate membrane blebbing and vesicle shedding by chemicals may be practical for the manipulation of membrane dynamics and the development of vesicle-inspired technologies using a wide variety of cell types.