A pilot study on using chlorine dioxide gas for disinfection of gastrointestinal endoscopes.

OBJECTIVES: This pilot study of employing chlorine dioxide (CD) gas to disinfect gastrointestinal endoscopes was conducted to meet the expectations of many endoscopy units in China for a high-efficiency and low-cost disinfectant. METHODS: An experimental prototype with an active circulation mode was designed to use CD gas to disinfect gastrointestinal endoscopes. One type of testing device composed of polytetrafluoroethylene (PTFE) tubes (2 m long, inner diameter 1 mm) and bacterial carrier containers was used to simulate the channel of the endoscope. PTFE bacterial carriers inoculated with Bacillus atrophaeus with or without organic burden were used to evaluate the sporicidal activity of CD gas. Factors including exposure dosage, relative humidity (RH), and flow rate (FR) influencing the disinfection effect of CD gas were investigated. Moreover, an autoptic disinfecting test on eight real gastrointestinal endoscopes after clinical use was performed using the experimental prototype. RESULTS: RH, exposure dosage, organic burden, and the FR through the channel significantly (P<0.05) affected the disinfection efficacy of CD gas for a long and narrow lumen. The log reduction increased as FR decreased. Treatment with 4 mg/L CD gas for 30 min at 0.8 L/min FR and 75% RH, resulted in complete inactivation of spores. Furthermore, all eight endoscopes with a maximum colony-forming unit of 915 were completely disinfected. The cost was only 3 CNY (0.46 USD) for each endoscope. CONCLUSIONS: The methods and results reported in this study could provide a basis for further studies on using CD gas for the disinfection of endoscopes.

Deletion of the antiphospholipid syndrome autoantigen ß2 -glycoprotein I potentiates the lupus autoimmune phenotype in a Toll-like receptor 7-mediated murine model.

OBJECTIVE: The BXSB.Yaa mouse strain is a model of systemic lupus erythematosus that is dependent on duplication of the Toll-like receptor 7 gene. The objective of this study was to systematically describe the amplified autoimmune phenotype observed when the soluble plasma protein ß2 -glycoprotein I (ß2 GPI) gene was deleted in male BXSB.Yaa mice. METHODS: We generated BXSB.Yaa and NZW mouse strains in which the ß2 GPI gene had been knocked out by backcrossing the wild-type strains with C57BL/6 ß2 GPI(-/-) mice for 10 generations. Sex- and age-matched mice of the various strains were housed under identical conditions and were killed at fixed time intervals. Serum and tissue specimens were collected at various time points. Lupus-associated autoantibodies, inflammatory cytokines, and the type I interferon (IFN) gene signature were measured. Flow cytometric analyses of lymphocyte populations were performed. The severity of glomerulonephritis was graded by 2 independent renal histopathologists. RESULTS: Male BXSB.Yaa ß2 GPI(-/-) mice developed significant lymphadenopathy and splenomegaly compared with age-matched controls. Male BXSB.Yaa ß2 GPI(-/-) mice also had significantly higher levels of autoantibodies, increased levels of inflammatory cytokines including tumor necrosis factor α, interleukin-6, and BAFF, and more severe glomerulonephritis. The type I IFN gene signature in male BXSB.Yaa ß2 GPI(-/-) mice was significantly higher than that in control mice. Male BXSB.Yaa ß2 GPI(-/-) mice also had marked dysregulation of various B cell and T cell populations in the spleens and lymph nodes and a disturbance in apoptotic cell clearance. CONCLUSION: Deletion of ß2 GPI accelerates and potentiates the autoimmune phenotype in male BXSB.Yaa mice.

Evaluation of vaporized hydrogen peroxide fumigation as a method for the bio-decontamination of the high efficiency particulate air filter unit.

OBJECTIVE: To evaluate the performance of vaporized hydrogen peroxide (VHP) for the bio-decontamination of the high efficiency particulate air (HEPA) filter unit. METHODS: Self-made or commercially available bioindicators were placed at designated locations in the HEPA filter unit under VHP fumigation. The spores on coupons were then extracted by 0.5 h submergence in eluent followed by 200- time violent knocks. RESULTS: Due to the presence of HEPA filter in the box, spore recovery from coupons placed at the bottom of the filter downstream was significantly higher than that from coupons placed at the other locations. The gap of decontamination efficiency between the top and the bottom of the filter downstream became narrower with the exposure time extended. The decontamination efficiency of the bottom of the filter downstream only improved gently with the injection rate of H2O2 increased and the decontamination efficiency decreased instead when the injection rate exceeded 2.5 g/min. The commercially available bioindicators were competent to indicate the disinfection efficiency of VHP for the HEPA filter unit. CONCLUSION: This assay developed can detect all 16 ß-lactams demanded by the European Union (EU). The whole procedure takes only 45 min and can detect 42 samples and the standards with duplicate analysis.

Association between the interleukin-13 gene and development of chronic obstructive pulmonary disease in southern Chinese Han population: a case-control study / 中华医学杂志(英文版)

<p><b>BACKGROUND</b>Interleukin-13 (IL-13) has been implicated to be responsible for recruitment of inflammatory cells from the blood to the lung, regulation of matrix metalloproteinase and induction of mucin production and secretion in chronic obstructive pulmonary disease (COPD). We determined plasma IL-13 levels in patients with COPD and investigated its association with common polymorphisms of IL-13 gene in a case-control study.</p><p><b>METHODS</b>We genotyped 160 cases and 175 control subjects in a local hospital using Mass-Array(TM) Technology Platform then tested the association of four SNPs in IL-13 (rs1295685, rs1800925, rs1881457, rs20541) with COPD, and then determined plasma IL-13 levels in patients with COPD and controls.</p><p><b>RESULTS</b>Association was found between IL-13 gene SNPs (rs20541 and rs1800925) and an increased risk of COPD. By linkage disequilibrium (LD) analysis, two blocks (rs1881457 and rs1800925; rs20541 and rs1295685) were found. The risk of COPD was found associated with the IL-13 gene polymorphism among southern Chinese Han population. Plasma IL-13 level was increased in COPD patients compared with controls.</p><p><b>CONCLUSIONS</b>The polymorphism of the IL-13 gene is associated with an increased risk of COPD in southern Chinese Han population. Plasma IL-13 levels were found elevated in patients with COPD.</p>

Decontamination of Bacillus subtilis var. niger spores on selected surfaces by chlorine dioxide gas.

OBJECTIVE: Chlorine dioxide (CD) gas has been used as a fumigant in the disinfection of biosafety laboratories. In this study, some experiments were conducted to assess the inactivation of spores inoculated on six materials [stainless steel (SS), painted steel (PS), polyvinyl chlorid (PVC), polyurethane (PU), glass (GS), and cotton cloth (CC)] by CD gas. The main aims of the study were to determine the sporicidal efficacy of CD gas and the effect of prehumidification before decontamination on sporicidal efficacy. METHODS: Material coupons (1.2 cm diameter of SS, PS, and PU; 1.0 cm×1.0 cm for PVC, GS, and CC) were contaminated with 10 µl of Bacillus subtilis var. niger (ATCC 9372) spore suspension in mixed organic burden and then dried in a biosafety cabinet for 12 h. The spores were recovered by soaking the coupons in 5 ml of extraction liquid for 1 h and then vortexing the liquid for 1 min. RESULTS: The log reductions in spore numbers on inoculated test materials exposed to CD gas [0.080% (volume ratio, v/v) for 3 h] were in the range of from 1.80 to 6.64. Statistically significant differences were found in decontamination efficacies on test material coupons of SS, PS, PU, and CC between with and without a 1-h prehumidification treatment. With the extraction method, there were no statistically significant differences in the recovery ratios between the porous and non-porous materials. CONCLUSIONS: The results reported from this study could provide information for developing decontamination technology based on CD gas for targeting surface microbial contamination.

One-pot fabrication and antimicrobial properties of novel PET nonwoven fabrics.

Recently, with the ever-growing demand for healthy living, more and more research is focused on materials capable of killing harmful microorganisms around the world. It is believed that designing such protective materials for hygienic and biomedical applications can benefit people in professional areas and daily life. Thus, in this paper, one novel kind of antibacterial poly(ethylene terephthalate) (PET) nonwoven fabrics was conveniently one-pot prepared, with the combined immobilization of two biological antimicrobial agents, i.e. ε-polylysine and natamycin, by using the soft methacrylate nonwoven fabrics adhesives. Then, the antimicrobial activities of the functional fabrics were investigated by using the standard shaking-flask method, showing excellent antibacterial efficiency (AE) against both Escherichia coli (8099) and Staphylococcus aureus (ATCC 6538) (AE > 99.99%) compared with untreated PET nonwoven fabrics. The anti-bioaerosol tests also showed similar trends. Meantime, scanning electron microscopy analysis indicated that the bacteria on the antibacterial PET appeared to be partly bacteriolyzed and showed much less viability than those on the pristine ones. Moreover, the long residual biocidal action of such modified PET fabrics was also evaluated, and the antibacterial activity of antibacterial fibers was unaffected by the 3 month artificially accelerated aging.

Novel assays of thrombogenic pathogenicity in the antiphospholipid syndrome based on the detection of molecular oxidative modification of the major autoantigen ß2-glycoprotein I.

OBJECTIVE: Beta-2-glycoprotein I (ß2 GPI) constitutes the major autoantigen in the antiphospholipid syndrome (APS), a common acquired cause of arterial and venous thrombosis. We recently described the novel observation that ß2 GPI may exist in healthy individuals in a free thiol (biochemically reduced) form. The present study was undertaken to quantify the levels of total, reduced, and posttranslationally modified oxidized ß2 GPI in APS patients compared to various control groups. METHODS: In a retrospective multicenter analysis, the proportion of ß2 GPI with free thiols in serum from healthy volunteers was quantified. Assays for measurement of reduced as well as total circulating ß2 GPI were developed and tested in the following groups: APS (with thrombosis) (n=139), autoimmune disease with or without persistent antiphospholipid antibodies (aPL) but without APS (n=188), vascular thrombosis without APS or aPL (n=38), and healthy volunteers (n=91). RESULTS: Total ß2 GPI was significantly elevated in patients with APS (median 216.2 µg/ml [interquartile range 173.3-263.8]) as compared to healthy subjects (median 178.4 µg/ml [interquartile range 149.4-227.5] [P<0.0002]) or control patients with autoimmune disease or vascular thrombosis (both P<0.0001). The proportion of total ß2 GPI in an oxidized form (i.e., lacking free thiols) was significantly greater in the APS group than in each of the 3 control groups (all P<0.0001). CONCLUSION: This large retrospective multicenter study shows that posttranslational modification of ß2 GPI via thiol-exchange reactions is a highly specific phenomenon in the setting of APS thrombosis. Quantification of posttranslational modifications of ß2 GPI in conjunction with standard laboratory tests for APS may offer the potential to more accurately predict the risk of occurrence of a thrombotic event in the setting of APS.

New technique: Development of a large-scale isolation chamber system for the safe and humane care of medium-sized laboratory animals harboring infectious diseases.

The close phylogenetic relationship between humans and non-human primates makes non-human primates an irreplaceable model for the study of human infectious diseases. In this study, we describe the development of a large-scale automatic multi-functional isolation chamber for use with medium-sized laboratory animals carrying infectious diseases. The isolation chamber, including the transfer chain, disinfection chain, negative air pressure isolation system, animal welfare system, and the automated system, is designed to meet all biological safety standards. To create an internal chamber environment that is completely isolated from the exterior, variable frequency drive blowers are used in the air-intake and air-exhaust system, precisely controlling the filtered air flow and providing an air-barrier protection. A double door transfer port is used to transfer material between the interior of the isolation chamber and the outside. A peracetic acid sterilizer and its associated pipeline allow for complete disinfection of the isolation chamber. All of the isolation chamber parameters can be automatically controlled by a programmable computerized menu, allowing for work with different animals in different-sized cages depending on the research project. The large-scale multi-functional isolation chamber provides a useful and safe system for working with infectious medium-sized laboratory animals in high-level bio-safety laboratories.

Naturally occurring free thiols within beta 2-glycoprotein I in vivo: nitrosylation, redox modification by endothelial cells, and regulation of oxidative stress-induced cell injury.

ß2-Glycoprotein I (ß2GPI) is an evolutionary conserved, abundant circulating protein. Although its function remains uncertain, accumulated evidence points toward interactions with endothelial cells and components of the coagulation system, suggesting a regulatory role in vascular biology. Our group has shown that thioredoxin 1 (TRX-1) generates free thiols in ß2GPI, a process that may have a regulatory role in platelet adhesion. This report extends these studies and shows for the first time evidence of ß2GPI with free thiols in vivo in both multiple human and murine serum samples. To explore how the vascular surface may modulate the redox status of ß2GPI, unstimulated human endothelial cells and EAhy926 cells are shown to be capable of amplifying the effect of free thiol generation within ß2GPI. Multiple oxidoreductase enzymes, such as endoplasmic reticulum protein 46 (ERp 46) and TRX-1 reductase, in addition to protein disulfide isomerase are secreted on the surface of endothelial cells. Furthermore, one or more of these generated free thiols within ß2GPI are also shown to be nitrosylated. Finally, the functional significance of these findings is explored, by showing that free thiol-containing ß2GPI has a powerful effect in protecting endothelial cells and EAhy926 cells from oxidative stress-induced cell death.

The Diacylglycerol-dependent translocation of ras guanine nucleotide-releasing protein 4 inside a human mast cell line results in substantial phenotypic changes, including expression of interleukin 13 receptor alpha2.

Ras guanine nucleotide-releasing protein 4 (RasGRP4) is a mast cell (MC)-restricted guanine nucleotide exchange factor and diacylglycerol (DAG)/phorbol ester receptor. An RasGRP4-defective variant of the human MC line HMC-1 was used to create stable clones expressing green fluorescent protein-labeled RasGRP4 for monitoring the movement of this protein inside MCs after exposure to phorbol 12-myristate 13-acetate (PMA), and for evaluating the protein's ability to control gene expression. RasGRP4 resided primarily in the cytosol. After exposure to PMA, RasGRP4 quickly translocated to the inner leaflet of the cell's plasma membrane. 15-30 min later, this signaling protein translocated from the plasma membrane to other intracellular sites. The translocation of RasGRP4 from the cytosol to its varied membrane compartments was found to be highly dependent on Phe(548) in the protein's C1 DAG/PMA-binding domain. Extracellular signal-regulated kinases 1 and 2 were activated during this translocation process, and c-kit/CD117 was lost from the cell's surface. Transcript-profiling approaches revealed that RasGRP4 profoundly regulated the expression of hundreds of genes in HMC-1 cells. For example, the expression of the transcript that encodes the interleukin (IL) 13 receptor IL-13Ralpha2 increased 61- to 860-fold in RasGRP4-expressing HMC-1 cells. A marked increase in IL-13Ralpha2 protein levels also was found. The accumulated data suggest RasGRP4 translocates to varied intracellular compartments via its DAG/PMA-binding domain to regulate signaling pathways that control gene and protein expression in MCs, including the cell's ability to respond to IL-13.

[High D-glucose alters PI3K and Akt signaling and leads to endothelial cell migration, proliferation and angiogenesis dysfunction].

OBJECTIVE: To investigate the effects of high D-glucose on migration, proliferation, and angiogenesis of endothelial cells and to make sure whether PI3K and Akt signaling pathway plays an important role in the pathogenesis of diabetic vascular complications. METHODS: Human umbilical vein endothelial cells (HUVECs) were cultured. D-glucose of the concentrations of 5 mmol/L, 15 mmol/L, and 30 mmol/L and mannitol of the concentrations of 5 mmol/L, 15 mmol/L, and 30 mmol/L were added in to the medium, the migration rate of the cells was measured by wound healing test and the cell proliferation was examined with CellTiter 96 AQ(ueous) One Solution cell proliferation assay. Matrigel was spread on 96-well plate, and culture of HUVECs with D-glucose and mannitol of different concentrations were added. Microscopic photography was used to calculate the total area of vascular bed, average vessel length, vessel number, branch points, so as to observe the angiogenesis. Immuno-precipitation was used to detect the expression of p85/PI3K. Western blotting was used to detect the protein expression of p85/PI3K, p-PI3K, GSK3beta (downstream kinase of Akt), p-Akt (Threonine308) and p-GSK3beta. LY294002, a PI3K inhibitor, of the concentrations of 0.1 micromol/L, 1 micromol/L, and 10 micromol/L was added into the culture fluid with 5 mmol/L D-glucose, then the endothelial cell migration, proliferation number, total area of blood bed, etc were observed. RESULTS: The migration rate of the 5 mmol/L D-glucose group was 100 +/- 23/microm2, and D-glucose dose-dependently decreased the migration rate, e.g. the migration rates of the 15 mmol/L and 30 mmol/L D-glucose groups were 77 +/- 18/microm2 and 46 +/- 18/microm2 respectively, both significantly lower than that of the 5 mmol/L D-glucose group (both P < 0.01). LY294002 of the concentrations of 0.1 micromol/L, 1 micromol/L, and 10 micromol/L dose-dependently decrease the endothelial cells migration rates to 68 +/- 16/microm2, 36 +/- 12/microm2, and 13 +/- 3/microm2 respectively (all P < 0.01) The cell proliferation rate of the 5 mmol/L, 15 mmol/L) and 30 mmol/L D-glucose groups were 59,128 +/- 7415/well, 33,144 +/- 9082/well, and 11,625 +/- 4196/well respectively, showing that D-glucose dose-dependently decreased the cell proliferation (all P < 0.01). LY294002 of the concentrations of 0.1 micromol/L, 1 micromol/L, and 10 micromol/L dose-dependently decrease the endothelial cell proliferation to 42,560 +/- 4213/well, 17,688 +/- 7198/well, and 5704 +/- 558/well respectively (all P < 0.01). 15 mmol/L and 30 mmol/L D-glucose decreased the numbers of total area of vascular bed, average tubule length, number of capillaries, and number of vessel branch pint formed on the Matrigel. LY294002 dose-dependently inhibited the angiogenesis (P < 0.05 or P < 0.01) 15 mmol/L and 30 mmol/L D-glucose dose-dependently inhibited the phosphorylation of p85/P13K and Akt (P < 0.05 and P < 0.01). However, D-glucose did not influence the protein expression of p85/PI3K and Akt. Mannitol did not influence the cell proliferation, angiogenesis, and the expression of p85/PI3K, phosphorylated p85/PI3K, Akt, phosphorylated Akt (Thr308), and phosphorylated GSK3beta. CONCLUSION: Hyperglycemia-impaired PI3K-Akt signaling may lead to migration, proliferation and angiogenesis dysfunction of endothelial cells in diabetes patients, which is likely to contribute to the pathogenesis of diabetic vascular complications.

Hemopoietic cells with features of the mast cell and basophil lineages and their potential role in allergy.

Human mast cells (MCs) and basophils play a key role in the pathogenesis of allergic disorders, not only by producing inflammatory and fibrogenic mediators, but also by directly and indirectly secreting various cytokines and chemokines. Although mast cells and basophils have differences in many properties, recent evidence suggests that human MCs and basophils may be derived from a common progenitor, and their contents and phenotypes may be reversibly altered in a variety of allergic disorders. The study of FcetaRI signalling of mast cell and basophils offers new opportunities for therapeutic interventions based on the specific inhibition of the earliest events in allergic diseases. This article reviews the origin, differentiation, morphology and phenotypic properties of MCs and basophils, focussing particularly on the possible pathogenic role of MCs and basophils in allergy and biochemical targets for therapeutic interventions in allergic diseases.

An antibody raised against in vitro-derived human mast cells identifies mature mast cells and a population of cells that are Fc epsilon RI(+), tryptase(-), and chymase(-) in a variety of human tissues.

Selective markers for human mast cells are of paramount importance for understanding their role in physiological and pathological processes. A mouse monoclonal antibody (MAb) designated 2C7, raised against in vitro-derived human mast cells, was used in immunoenzymatic analysis of sections from a variety of human organs. Double immunolabeling with 2C7 and tryptase, chymase, Fc epsilon RIalpha, and c-kit was performed on cryostat tissue sections from skin, colon, uterus, breast, stomach, bladder, and lung. MAb 2C7 stained greater than 93% of the tryptase(+) or chymase(+) mast cells in all tissues examined. In addition, the majority of cells stained with the tryptase or chymase also stained for Fc epsilon RIalpha. However, there were a significant number of Fc epsilon RIalpha(1) cells in all tissues studied that were tryptase(-) and/or chymase(-). In contrast, MAb 2C7 in double immunoenzymatic staining co-localized with 93-96% of the Fc epsilon RIalpha(1) cells in all tissues. Analysis for c-kit expression on the different tissues revealed that the majority of tryptase(+) or chymase(+) cells in skin, uterus, bladder, and lung stained with c-kit. However, only approximately 70-78% of tryptase(+) cells in colon and stomach were c-kit(+). These data suggest that MAb 2C7 appears to identify mature mast cells and a population of Fc epsilon RIalpha(1), chymase(-), and tryptase(-) cells in a variety of human tissues.

IL-16 regulation of human mast cells/basophils and their susceptibility to HIV-1.

AIDS patients often contain HIV-1-infected mast cells (MCs)/basophils in their peripheral blood, and in vivo-differentiated MCs/basophils have been isolated from the blood of asthma patients that are HIV-1 susceptible ex vivo due to their surface expression of CD4 and varied chemokine receptors. Because IL-16 is a ligand for CD4 and/or an undefined CD4-associated protein, the ability of this multifunctional cytokine to regulate the development of human MCs/basophils from nongranulated progenitors residing in cord or peripheral blood was evaluated. After 3 wk of culture in the presence of c-kit ligand, IL-16 induced the progenitors residing in the blood of normal individuals to increase their expression of chymase and tryptase about 20-fold. As assessed immunohistochemically, >80% of these tryptase(+) and/or chymase(+) cells expressed CD4. The resulting cells responded to IL-16 in an in vitro chemotaxis assay, and this biologic response could be blocked by anti-IL-16 and anti-CD4 Abs as well as by a competitive peptide inhibitor corresponding to a sequence in the C-terminal domain of IL-16. The additional finding that IL-16 induces calcium mobilization in the HMC-1 cell line indicates that IL-16 acts directly on MCs and their committed progenitors. IL-16-treated MCs/basophils also are less susceptible to infection by an M/R5-tropic strain of HIV-1. Thus, IL-16 regulates MCs/basophils at a number of levels, including their vulnerability to retroviral infection.

[A vertical vibration model of human body in supine position].

Objective. To establish the models of head, abdomen, and chest of supine human body respectively under vertical vibration. Method. The mechanical impedance of 12 healthy volunteers aged 24-56 was measured under vertical white noise stimulus in the frequency range of 2-35 Hz. To explain these findings, the model of head was proposed, the models of abdomen and chest were computed by way of an optimization procedure. Result. The models of abdomen and chest are three-degree-of-freedom and the head is rigid. Conclusion. The mechanical impedance of the supine human body is linear and sole. The established models of head, abdomen and chest of supine human body when subjected to vertical vibration are useful for calculating and evaluating the comfort of supine human body under whole-body vibration.