Non-coated Tubes Research Articles

Anti-inflammatory and Anti-bacterial Effects of Allicin-coated Tracheal Tube on Trachea Mucosa.

Allicin has been known to improve wound healing via antimicrobial and anti-inflammatory properties. The aim of this study was to evaluate whether an allicin-coated tracheal tube can prevent tracheal stenosis through improving wound healing after tracheal injury. Allicin-coated silicone tracheal tube (t-tube) was prepared by the polydopamine-mediated coating method. Tracheal mucosa was injured, and an allicin-coated t-tube was placed into the trachea to evaluate mucosal changes until designated time point. Anti-inflammatory, anti-bacterial and cytotoxic effects of allicin were also investigated in in vitro. Allicin- coated silicone was not cytotoxic, and it showed anti-inflammatory and anti-bacterial effects in in vitro analysis. The use of allicin-coated t-tube in a rabbit model showed favorable mucosal healing with significant decrease of proinflammatory cytokines compared to the non-coated tube group. The allicin-coated tube showed obvious decreased number of cocci-shaped bacterial attached to the tube surface. From the histological point of view, the allicin- coated tube showed faster regeneration of the normal respiratory epithelial structure compared to the non-coated group. Allicin-coated t-tube showed anti-inflammatory and anti-bacterial effects on injured tracheal mucosa. We suggest that allicin-coated t-tube can be used for promoting physiological wound healing to prevent laryngotracheal stenosis.

Internal condensation heat transfer in a hydrophobic near-horizontal tube with high pressure and low mass flux

Based on the potential of hydrophobic surface treatment leading to a significant increase in condensation heat transfer, in this study, condensation phenomena of water with hydrophobic coating in a nearly-horizontal tube were experimentally investigated whether increase by hydrophobic surface modifications is retained in extreme flow conditions. Various pressurized conditions (0.6 ≤ P ≤ 1.5 MPa) for different mass fluxes (7.0 ≤ G ≤ 27.5 kg/(m2·s)) were tested. The hydrophobically-coated tubes showed 8.95 times higher heat transfer coefficient h than non-coated tube at P = 0.6 MPa, but the increase became negligible as P approached 1.5 MPa. The result is consistent with the hypothesis that dropwise condensation is promoted by the hydrophobic coating at low P, where surface tension σ is high, but the effect is not sustained as P increases and σ decreases. Under a given P, h increased as G increased. The high G is expected to encourage droplet departure in the partial dropwise mode, and this increase in departure rate contributes to increase h. The experimental results are described with a newly-proposed dropwise condensation heat transfer model for hydrophobically-coated tubes that have dropwise condensation in the stratified flow regime.

Improving chondrocyte harvests with poly(2-hydroxyethyl methacrylate) coated materials in the preparation for cartilage tissue engineering.

Remarkable advances have been made in cartilage regenerative medicine to cure congenital anomalies including microtia, tissue defects caused by craniofacial injuries, and geriatric diseases such as osteoarthritis. However, those procedures require a substantial quantity of chondrocytes for tissue engineering. Previous studies have required several passages to obtain sufficient cell numbers for three-dimensional and monolayer cultures. Thus, our objective was to improve the quantity of chondrocytes that can be obtained by examining an anti-fouling polyhydrophilic chemical called poly(2-hydroxyethyl methacrylate) (pHEMA). To determine the effectiveness of the chemical, pHEMA solution was applied via dip-coating to centrifuge tubes, serological pipettes, and pipette tips. The cell quantity obtained during standard cell culturing and passaging procedures was measured alongside non-coated materials as a control. A significant 2.2-fold increase of chondrocyte yield was observed after 2 passages when pHEMA was applied to the tubes compared to when non-coated tubes were utilized. The 3-dimensional chondrocyte pellets prepared from the respective cell populations and transplanted into nude mice were histologically and biochemically analyzed. No evidence of difference in matrix production for in vitro and in vivo cultures was found as well as similar proliferation rates and colony formation abilities. The use of pHEMA provides a powerful alternative method for expanding the quantity of chondrocytes harvested and handled during cell isolation and passaging to enhance cartilage tissue engineering.

Surface-modified silicone T-tubes for prevention of tracheal stenosis in a rabbit model.

This study was conducted to determine whether a surface-modified tracheal T-tube can prevent tracheal stenosis in a rabbit model. Animal model study. We designed surface-modified tracheal T-tubes in which silicone rubber was modified by coating it with hyaluronic acid (HA) or polyethylene glycol (PEG). Sixteen rabbits were divided into four insertion groups: normal, silicone tube, silicone tube coated with HA, and silicone tube coated with PEG. Surface-modified tubes were inserted into the tracheal lumen after a scraping injury on the inner tracheal mucosa around the preformed tracheostoma. Laryngoscopy was performed to evaluate formation of stenosis in the trachea. Histological examinations were performed to evaluate epithelial thickness, inflammatory response, and fibrosis. Endoscopic finding showed that the HA- and PEG-coated tube groups had less granulation tissue in the trachea than the noncoated tube group. Greater epithelialization was observed in the noncoated tube group than in the normal group. HA- and PEG-coated tube groups showed a tendency to decreasing epithelialization compared with the noncoated tube group. More inflammatory cells were observed in the noncoated tube group than in the normal group, and fewer inflammatory cells were observed in the HA- and PEG-coated tube groups than in the noncoated tube group. The noncoated tube group showed a greater area of fibrosis than the HA- and PEG-coated tube groups. A surface-modified tracheal T-tube may have a favorable effect on reducing tracheal stenosis in a rabbit model. We suggest that local application of HA and PEG should be further researched for prevention of tracheal stenosis. Our rabbit model could be helpful in providing an additional scenario for evaluating new strategies to prevent tracheal stenosis. NA

Impact of non-di-(2-ethylhexyl)phthalate cardiopulmonary bypass tubes on inflammatory cytokines and coagulation-fibrinolysis systems during cardiopulmonary bypass

Di-(2-ethylhexyl)phthalate (DEHP), an excellent plasticizer for poly(vinyl chloride) (PVC), is a known endocrine-disrupting chemical. This study was designed to investigate whether a new non-DEHP bilayer tube reduced the release of DEHP, suppressed inflammatory cytokines, and altered coagulation-fibrinolysis systems. Sixteen patients undergoing coronary artery bypass grafting (CABG) were randomly assigned to the non-DEHP bilayer group (group B, n = 8), or the noncoated PVC group (group N, n = 8). The level of DEHP in the blood was measured before and after cardiopulmonary bypass (CPB). The levels of interleukin-6 (IL-6), D-dimer, and thrombin-antithrombin complex (TAT) were also measured at six points during and after CPB. DEHP was significantly lower in group B (472 +/- 141 ng/ml) after CPB compared with group N (2094 +/- 1046 ng/ml). The IL-6 level was significantly lower in group B (151 +/- 131 pg/ml) than group N (206 +/- 224 pg/ml) 180 min after protamine administration. The D-dimer level was significantly lower in group B 60 min after protamine administration (6.2 +/- 2.4 microg/ml in group B vs 10.4 +/- 4.5 microg/ml in group N) and 180 min after protamine administration (4.4 +/- 0.7 microg/ml in group B vs 7.3 +/- 2.7 microg/ml in group N). Group B had a tendency toward reduced postoperative bleeding compared with group N at any time. The bilayer tube was superior to the noncoated tube in terms of the inhibition of DEHP release, inflammatory cytokines, and the fibrinolysis system.

Increased gene transfer into human cord blood cells by centrifugation-enhanced transduction in fibronectin fragment-coated tubes.

We investigated whether transduction of human cord blood progenitor cells can be increased by spinoculation in fibronectin fragment CH-296 (FN)-coated tubes. Bicistronic vectors PA317/LgEIN, containing the enhanced green fluorescent protein (EGFP) and neomycin phosphotransferase (neo) genes, and PG13/LgDIN, containing the dihydrofolate reductase and neo genes, were used to transduce CD34-enriched human cord blood cells. Transduction by spinoculation in FN-coated tubes (spin/FN+) was compared with spinoculation in noncoated tubes (spin/FN-) and transduction in plates coated with FN (plate/FN+). Antibody to TGF-beta was added to spin/FN+ to evaluate its impact on transduction. Using producer cell line PA317/LgEIN for transduction of CD34+ cord blood cells, FACS analysis for expression of EGFP revealed mean transduction of 30.6+/-4.3, 9.1+/-1.6, and 21.1+/-6.5% of CD34+ cells in the spin/FN+, spin/FN-, and plate/FN+ arms, respectively. Transduction of CD+CD38low cells was also higher in the spin/FN+ arm as compared with transduction in the spin/FN- arm. These results were corroborated by colony-forming assays. Antibody to TGF-beta did not further increase transduction. Using a different producer cell line, PG13/pLgDIN, a higher number of G418-resistant CFU-GM was observed in the spin/FN+ as compared with the plate/FN+ and spin/FN-arms. NOD/SCID mice were transplanted with transduced, CD34-enriched human cord blood cells, and persistence of transduced human cells was analyzed in the mice marrows after 6-8 weeks: 32.8, 6.0, and 23.9% human G418-resistant CFU-GM colonies were observed in the spin/FN+, spin/FN-, and plate/FN+ arms, respectively. These results suggest that spinoculation in FN-coated tubes increases transduction of early human cord blood progenitor cells as compared with spinoculation in noncoated tubes.

Increased adsorption of high molecular weight kininogen to heparin-coated artificial surfaces and correlation to hemocompatibility

During the past 10 years investigations have demonstrated that heparin-coated devices used for extracorporeal circuits show an improved hemocompatibility. We investigated the pathway of adsorption of plasma proteins at heparin-coated artificial surfaces and the further activation of the humoral and cellular defense mechanisms of the blood. Twenty milliliters of fresh human blood (1 IU heparin/ml) filled a 50 cm long tubes (with and without covalent heparin-coating), prepared as an in vitro “Closed-Loop” model and recirculated at a temperature of 37°C. After 5, 15, 30, 60 and 120 min fibrinogen and high molecular weight kininogen (HMWK) adsorption was measured by a newly developed modified ELISA technique. In addition, changes in coagulation and platelet activation were measured by well established assays. High concentrations of fibrinogen were detected after very short blood material contact, both on uncoated as well as heparin-coated tubes. However, high amounts of HMWK were only found on the heparin-bonded surfaces. In addition, the concentrations of the soluble coagulation marker prothrombin fragment F1+2 and the marker for platelet activation β-thromboglobulin were significantly higher in the non-coated tubes. We presume that adsorption of HMWK to heparin-coated surfaces contributes to the improved hemocompatibility of these bondings.

Prevention of thrombin/antithrombin III reaction in the presence of protamine or polybrene

The rate of the thrombin/antithrombin III (AT III) reaction was decreased in the presence of free polybrene or protamine. The reaction rate was also decreased in protamine-coated tubes and tubes on which polybrene was absorbed nonspecifically. The reaction was also prevented when either thrombin or AT III was transfered into noncoated tubes after instantaneous contact with protamine-coated tubes or tubes with polybrene. These facts suggest that the thrombin/AT III reaction rate is determined with concentrations of reactive protein species.

Assessment of murine lymph node lymphocyte priming with the tetrasialoganglioside GQ1b.

In vivo priming of lymphocytes by gangliosides was tested following active immunization of mice with the tetrasialoganglioside GQ1b coupled to a copolymer of L-lysine and DL-alanine. Lymphocytes derived from potential lymph nodes 17 days after immunization were triggered to incorporate tritiated thymidine after a 4-day incubation in polypropylene tubes precoated with GQ1b. Non-primed lymph node lymphocytes, primed lymphocytes incubated in non-coated tubes, and, more interestingly, primed lymphocytes incubated with the soluble ganglioside did not undergo mitogenic stimulation. The data suggest that the evaluation of the extent of in vivo priming of lymphocytes by gangliosides can be achieved only if these glycosphingolipids are bound to the substratum, whereas when applied to primed cells in soluble form they inhibit mitogenic activation.