Adapting re-usable elastomeric respirators to utilise anaesthesia circuit filters using a 3D-printed adaptor - a potential alternative to address N95 shortages during the COVID-19 pandemic

The COVID‐19 pandemic has increased the demand for disposable N95 respirators. Re‐usable elastomeric respirators may provide a suitable alternative. Proprietary elastomeric respirator filters may become depleted as demand increases. An alternative may be the virus/bacterial filters used in anaesthesia circuits, if they can be adequately fitted onto the elastomeric respirators. In addition, many re‐usable elastomeric respirators do not filter exhaled breaths. If used for sterile procedures, this would also require modification. We designed a 3D‐printed adaptor that permits elastomeric respirators to interface with anaesthesia circuit filters and created a simple modification to divert exhaled breaths through the filter. We conducted a feasibility study evaluating the performance of our modified elastomeric respirators. A convenience sample of eight volunteers was recruited. Quantitative fit testing, respiratory rate and end‐tidal carbon dioxide were recorded during fit testing exercises and after 1 h of wear. All eight volunteers obtained excellent quantitative fit testing throughout the trial. The mean (SD) end‐tidal carbon dioxide was 4.5 (0.5) kPa and 4.6 (0.4) kPa at baseline and after 1 h of wear (p = 0.148). The mean (SD) respiratory rate was 17 (4) breaths.min⁻¹ and 17 (3) breaths.min⁻¹ at baseline and after 1 h of wear (p = 0.435). Four out of eight subjects self‐reported discomfort; two reported facial pressure, one reported exhalation resistance and one reported transient dizziness on exertion. Re‐usable elastomeric respirators to utilise anaesthesia circuit filters through a 3D‐printed adaptor may be a potential alternative to disposable N95 respirators during the COVID‐19 pandemic.

Resveratrol inhibits Porphyromonas gingivalis lipopolysaccharide-induced endothelial adhesion molecule expression by suppressing NF-kappaB activation

P. gingivalis is a major pathogen that is involved in the onset and progression of periodontal disease. This study investigated the effect of resveratrol, a naturally occurring polyphenol, on P. gingivalis LPS-accelerated vascular inflammation, a key step in the progression of periodontitis. Resveratrol significantly inhibited the P. gingivalis LPS-induced adhesion of leukocytes to endothelial cells and to the aortic endothelium by down-regulating the cell adhesion molecules, ICAM-1 and VCAM-1. Moreover, the inhibition of the P. gingivalis LPS-induced cell adhesion molecules by resveratrol was mainly mediated by nuclear factor-kappaB (NF-kappaB). Resveratrol suppressed P. gingivalis LPS-stimulated IkappaBalpha phosphorylation and nuclear translocation of the p65 subunit of NF-kappaB in HMECs. Overall, these findings suggest that resveratrol significantly attenuates the P. gingivalis LPS-induced monocyte adhesion to the endothelium by suppressing the expression of the NF-kappaB-dependent cell adhesion molecules, suggesting its therapeutic role in periodontal pathogen-induced vascular inflammation.

Visfatin enhances ICAM-1 and VCAM-1 expression through ROS-dependent NF-kappaB activation in endothelial cells

Visfatin has recently been identified as a novel visceral adipokine which may be involved in obesity-related vascular disorders. However, it is not known whether visfatin directly contributes to endothelial dysfunction. Here, we investigated the effect of visfatin on vascular inflammation, a key step in a variety of vascular diseases. Visfatin induced leukocyte adhesion to endothelial cells and the aortic endothelium by induction of the cell adhesion molecules, ICAM-1 and VCAM-1. Promoter analysis revealed that visfatin-mediated induction of CAMs is mainly regulated by nuclear factor-kappaB (NF-kappaB). Visfatin stimulated IkappaBalpha phosphorylation, nuclear translocation of the p65 subunit of NF-kappaB, and NF-kappaB DNA binding activity in HMECs. Furthermore, visfatin increased ROS generation, and visfatin-induced CAMs expression and NF-kappaB activation were abrogated in the presence of the direct scavenger of ROS. Taken together, our results demonstrate that visfatin is a vascular inflammatory molecule that increases expression of the inflammatory CAMs, ICAM-1 and VCAM-1, through ROS-dependent NF-kappaB activation in endothelial cells.

Porphyromonas gingivalis, periodontal pathogen, lipopolysaccharide induces angiogenesis via extracellular signal-regulated kinase 1/2 activation in human vascular endothelial cells

Porphyromonas gingivalis is a major periodontal pathogen. The lipopolysaccharide (LPS) secreted from P. gingivalis is implicated in the initiation and progression of periodontitis. Aberrant angiogenesis is often associated with lesion formation in chronic periodontitis. In this study, we report that P. gingivalis LPS activates angiogenic cascade, migration, invasion and tube formation in human umbilical vein endothelial cells (HUVECs). Furthermore, P. gingivalis LPS potently stimulated in vivo neovascularization in chick chorioallantoic membrane (CAM) and the mouse Matrigel plug assay. P. gingivalis LPS had no effect on the expression of vascular endothelial growth factor (VEGF) or its receptor, Flk-1, implying that P. gingivalis LPS-induced angiogenesis may result from its direct action on endothelial cells. P. gingivalis LPS evoked activation of the mitogen-activated protein kinase ERK1/2 in HUVECs, which is closely linked to angiogenesis. Taken together, these results strongly suggest P. gingivalis LPS plays an important role in the pathological angiogenesis for periodontal diseases, such as periodontitis.

Inhibition of NF-kappa B activation through targeting I kappa B kinase by celastrol, a quinone methide triterpenoid

Celastrol, a quinone methide triterpenoid, was isolated as an inhibitor of NF-kappaB from Celastrus orbiculatus. This compound dose-dependently inhibited a variety of stimuli-induced NF-kappa B-regulated gene expression and the DNA-binding of NF-kappa B in different cell lines without affecting DNA-binding activity of AP-1. Preincubation of celastrol completely blocked the LPS-, TNF-alpha-, or PMA-induced degradation and phosphorylation of I kappa B alpha. Importantly, celastrol inhibited IKK activity and the constitutively active IKK beta activity in a dose-dependent manner without either affecting the NF-kappa B activation induced by RelA over-expression or directly suppressing the DNA-binding of activated NF-kappa B. However, mutation of cysteine 179 in the activation loop of IKK beta abolished sensitivity towards to celastrol, suggesting that celastrol suppressed the NF-kappa B activation by targeting cysteine 179 in the IKK. To verify that celastrol is a NF-kappa B inhibitor, we investigated its effect on some NF-kappa B target genes expressions. Celastrol prevented not only LPS-induced mRNA expression of iNOS and TNF-alpha, but also TNF-alpha-induced Bfl-1/A1 expression, a prosurvival Bcl-2 homologue. Consistent with these results, celastrol significantly suppressed the production of NO and TNF-alpha in LPS-stimulated RAW264.7 cells, and increased the cytotoxicity of TNF-alpha in HT-1080 cells. We also demonstrated that celastrol showed anti-inflammatory and anti-tumor activities in animal models. Taken together, this study extends our understanding on the molecular mechanisms underlying the anti-inflammatory and anti-cancer activities of celastrol and celastrol-containing medicinal plant, which would be a valuable candidate for the intervention of NF-kappa B-dependent pathological conditions.

Hypoxic induction of human visfatin gene is directly mediated by hypoxia-inducible factor-1

Visfatin has been originally identified as a growth factor for early stage B cells and recently known as an adipokine. Here, we report that hypoxia induces the visfatin mRNA and protein levels in MCF7 breast cancer cells. We also demonstrate that induction of visfatin gene is regulated by hypoxia-inducible factor-1alpha (HIF-1alpha). Moreover, 5'-flanking promoter region of human visfatin gene contains two functional HIF responsive elements (HREs), activating the expression of visfatin. Mutation of these HREs in the visfatin promoter abrogates activation of a luciferase reporter gene driven by visfatin promoter under hypoxia. Taken together, our results demonstrate that visfatin is a new hypoxia-inducible gene of which expression is stimulated through the interaction of HIF-1 with HRE sites in its promoter region.

Macrophage inhibitory cytokine-1 induces the invasiveness of gastric cancer cells by up-regulating the urokinase-type plasminogen activator system

In our search for genes associated with gastric cancer progression, we identified macrophage inhibitory cytokine-1 (MIC-1), a member of the transforming growth factor beta superfamily, as an overexpressed gene in gastric tumor tissues. Expression analysis of MIC-1 in gastric tumor tissues revealed a specific expression in gastric cancer cells, and this expression level was well correlated with invasive potential in various human gastric cancer cell lines. Stable transfection of MIC-1 into SNU-216, a human gastric cancer cell line, significantly increased its invasiveness. The overexpression of MIC-1 into SNU-216 cells significantly increased the activity of urokinase-type plasminogen activator (uPA), and the expressions of uPA and urokinase-type plasminogen activator receptor (uPAR). Similarly, the stimulation of gastric cancer cell lines with purified recombinant MIC-1 dose-dependently increased cell invasiveness, uPA activity, and uPA and uPAR expression. However, MIC-1 did not significantly suppress the proliferation of gastric cancer cell lines. We also found that the stimulation of human gastric cell lines with recombinant MIC-1 strongly induced activation of mitogen-activated protein kinase kinase-1/2 and extracellular signal-regulated kinase-1/2. Additional analysis revealed that PD98059, a selective inhibitor of mitogen-activated protein kinase kinase-1/2, suppressed not only gastric cancer cell invasiveness and uPA activity, but also the mRNA expressions of uPA and uPAR, as induced by recombinant MIC-1. Our results indicate that MIC-1 may contribute to the malignant progression of gastric cancer cells by inducing tumor cell invasion through the up-regulation of the uPA activation system via extracellular signal-regulated kinase-1/2-dependent pathway.

Syntenin is overexpressed and promotes cell migration in metastatic human breast and gastric cancer cell lines

Two human breast cancer cell lines of differing invasive and metastatic potential, MDA-MB-435 and MCF7, were examined using subtractive suppression hybridization in a search for any genes associated with metastasis. Of the 17 cDNAs identified as being differentially expressed genes, it was determined that syntenin was overexpressed in metastatic MDA-MB-435 cells. Expression analysis showed that the expression level of syntenin was well correlated with invasive and metastatic potential in various human breast and gastric cancer cell lines. Moreover, gastric tumor tissues exhibited a much higher syntenin mRNA expression than their normal counterparts. Syntenin-transfected MCF7 cells migrated more actively, and showed an increased invasion rate relative to vector-transfectants or parental MCF7 in vitro, without evidencing any effect on the adhesion to fibronectin, type I collagen and laminin. Similarly, the forced expression of syntenin to human gastric cancer cell line Az521 increased its migratory and invasive potential in vitro. Syntenin-expressing MCF7 cells were associated with the appearance of numerous cell surface extensions and with pseudopodia formation on collagen I, suggesting that syntenin may be involved in the signaling cascade to actin-reorganization. Mutation study suggested that PDZ2 domain of syntenin could be an essential role in its stimulatory effect on the cell migration. This is the first demonstration that syntenin, a PDZ motif-containing protein, can be overexpressed during the metastatic progression of human breast and gastric cancer cells and that it can function as a metastasis-inducing gene.

Kaurane diterpene, kamebakaurin, inhibits NF-kappa B by directly targeting the DNA-binding activity of p50 and blocks the expression of antiapoptotic NF-kappa B target genes

Kaurane diterpenes have been identified from numerous medicinal plants, which have been used for treatment of inflammation and cancer, however, their molecular mechanism of action remains unclear. We have previously shown that kamebakaurin and other three kaurane diterpenes selectively inhibit activation of transcription factor NF-kappaB, a central mediator of apoptosis and immune responses. We here demonstrate that kamebakaurin is a potent inhibitor of NF-kappaB activation by directly targeting DNA-binding activity of p50. Kamebakaurin prevented the activation of NF-kappaB by different stimuli in various cell types. Kamebakaurin did not prevent either stimuli-induced degradation of IkappaB-alpha or nuclear translocation of NF-kappaB, however, it significantly interfered DNA binding activity of activated NF-kappaB in cell and in vitro and preferentially prevented p50-mediated DNA-binding activity of NF-kappaB rather than that of RelA as measured using in vitro translated p50 and RelA proteins. Moreover, a p50 mutant with a Cys-62 --> Ser mutation was not inhibited with kamebakaurin, indicating that the effect of kamebakaurin was probably due to its interaction with cysteine 62 in p50. The covalent modification of p50 by kamebakaurin was further demonstrated by mass spectrometry analysis that showed an increase in the molecular mass of kamebakaurin-treated p50, and this modification was not reverted by addition of dithiothreitol. These results suggested that kamebakaurin exhibited its inhibitory activity by a direct covalent modification of cysteine 62 in the p50. Also, treatment of cells with kamebakaurin prevented the tumor necrosis factor-alpha (TNF-alpha)-induced expression of antiapoptotic NF-kappaB target genes encoding c-IAP1 (hiap-2) and c-IAP2 (hiap-1), members of the inhibitor of apoptosis family, and Bfl-1/A1, a prosurvival Bcl-2 homologue, and augmented the TNF-alpha-induced caspase 8 activity, thereby resulting in sensitizing MCF-7 cells to TNF-alpha-induced apoptosis. Taken together, kamebakaurin is a valuable candidate for the intervention of NF-kappaB-dependent pathological conditions such as inflammation and cancer.

Furanoligularenone, an eremophilane from Ligularia fischeri, inhibits the LPS-induced production of nitric oxide and prostaglandin E2 in macrophage RAW264.7 cells

Furanoligularenone (1), a known eremophilane, was identified from Ligularia fischeri (Compositae) together with 3-oxo-8alpha-hydroxy-10alphaH-eremophila-1,7(11)-dien-12,8beta-olide (2) and 3-oxo-8alpha-methoxy-10alphaH-eremophila-1,7(11)-dien-12,8beta-olide (3), by its potent inhibition of LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in RAW 264.7 cells. Compound 1 also suppressed the expression of iNOS and COX-2 mRNA and protein in a dose-dependent manner. Taken together, compound 1 inhibits the production of NO and PGE2 at the transcription of iNOS and COX-2 genes, and would be responsible for the anti-inflammatory activities of the Ligularia fischeri.

Kaurane diterpenes from Isodon japonicus inhibit nitric oxide and prostaglandin E2 production and NF-kappaB activation in LPS-stimulated macrophage RAW264.7 cells

A methanolic extract of the whole plant of Isodon japonicus (Labiatae) showed potent inhibition on the LPS-induced nitric oxide (NO) and prostaglandin E2 (PGE2) production in RAW264.7 cells. Four known kaurane diterpenes were isolated by activity-guided fractionation and their structures were identified as kamebanin (1), kamebacetal A (2), kamebakaurin (3), excisanin A (4). All compounds also inhibited the LPS-induced NF-kappaB activation as assessed by NF-kappaB reporter assay and electrophoretic mobility shift assay (EMSA). Compounds 2-4 showed comparable inhibitory effects on the LPS-induced production of NO and PGE2, and activation of NF-kappaB without affecting cell viability. These results suggest that kaurane diterpenes could exert their inhibitory effects on the production of NO and PGE2 through the suppression of NF-kappaB activation, and be partially responsible for the anti-inflammatory activities of the genus Isodon.

A sesquiterpene lactone, costunolide, from Magnolia grandiflora inhibits NF-kappa B by targeting I kappa B phosphorylation

A sesquiterpene lactone, costunolide (CTN), was identified from Magnolia grandiflora together with parthenolide (PTN) by its strong inhibition of LPS-induced NF-kappa B activation. CTN, which showed more potent inhibition than PTN in the NF-kappa B activation, strongly suppressed nitric oxide (NO) production in LPS-stimulated RAW 264.7 cells. RT-PCR and Western blot analyses demonstrated that CTN suppressed the expression of iNOS mRNA and protein in a dose-dependent manner. CTN also significantly inhibited LPS-induced DNA-binding activity of NF-kappa B as well as the LPS-induced degradation of I kappa B-alpha and -beta. Furthermore, CTN inhibited LPS-induced phosphorylation of I kappa B-alpha. These findings support that CTN inhibits NO production by down-regulating iNOS expression, at least, in part through the inhibition of I kappa Bs' phosphorylation and degradation, which are essential for the activation of NF-kappa B.

Treatment of total hyphema with relatively low-dose tissue plasminogen activator

The purpose of this study is to investigate the efficacy of tissue plasminogen activator (tPA) in the treatment of total hyphema following ocular trauma or intraocular surgery. Three patients (3 eyes) representing unresolved total hyphema for more than 5 days and uncontrolled high intraocular pressure received intracameral injections of 10 microgram of recombinant tPA. Intracameral tPA injection resulted in complete resolution of hyphema in all 3 eyes. Resolution occurred mostly within 24 to 48 hours after injection. Possible side effects of tPA injection, such as increased intraocular pressure and corneal edema, were not observed. However, 1 eye had vitreous hemorrhage after repeated injections of tPA. Intracameral injection of tPA seems to be a safe and effective method for the treatment of unresolved total hyphema. However, repeated intracameral tPA injections may cause unwanted complications such as vitreous hemorrhage.