Sample records for bypass increases permeability

  1. Cell-permeable succinate prodrugs bypass mitochondrial complex I deficiency (United States)

    Ehinger, Johannes K.; Piel, Sarah; Ford, Rhonan; Karlsson, Michael; Sjövall, Fredrik; Frostner, Eleonor Åsander; Morota, Saori; Taylor, Robert W.; Turnbull, Doug M.; Cornell, Clive; Moss, Steven J.; Metzsch, Carsten; Hansson, Magnus J.; Fliri, Hans; Elmér, Eskil


    Mitochondrial complex I (CI) deficiency is the most prevalent defect in the respiratory chain in paediatric mitochondrial disease. This heterogeneous group of diseases includes serious or fatal neurological presentations such as Leigh syndrome and there are very limited evidence-based treatment options available. Here we describe that cell membrane-permeable prodrugs of the complex II substrate succinate increase ATP-linked mitochondrial respiration in CI-deficient human blood cells, fibroblasts and heart fibres. Lactate accumulation in platelets due to rotenone-induced CI inhibition is reversed and rotenone-induced increase in lactate:pyruvate ratio in white blood cells is alleviated. Metabolomic analyses demonstrate delivery and metabolism of [13C]succinate. In Leigh syndrome patient fibroblasts, with a recessive NDUFS2 mutation, respiration and spare respiratory capacity are increased by prodrug administration. We conclude that prodrug-delivered succinate bypasses CI and supports electron transport, membrane potential and ATP production. This strategy offers a potential future therapy for metabolic decompensation due to mitochondrial CI dysfunction. PMID:27502960

  2. Spironolactone increases permeability of visceral sheep peritoneum. (United States)

    Karioti, Aggeliki; Hatzoglou, Chrissi; Zarogiannis, Sotirios; Deligiorgi, Triantafyllia; Kourti, Panagiota; Giannopoulou, Myrto; Arampatzis, Spyros; Liakopoulos, Vassilios; Gourgoulianis, Konstantinos; Molyvdas, Paschalis-Adam; Stefanidis, Ioannis


    Aldosterone is a key component of the renin-angiotensin-aldosterone system, and spironolactone, an aldosterone receptor blocker, shows beneficial effects in patients with end-stage renal disease and heart failure. The aim of the present study was to investigate by means of Ussing chamber technique the effect of spironolactone on the transmesothelial permeability of visceral sheep peritoneum in vitro. Peritoneal samples from the omentum of adult sheep were collected immediately after slaughter in a cooled and oxygenated Krebs-Ringer bicarbonate (KRB) solution. Isolated intact sheets of peritoneum were mounted in an Ussing-type chamber. Spironolactone (10(-5) mol/L) was added apically and basolaterally to the KRB solution. The transmesothelial resistance (R) was measured before and serially for 30 minutes after the addition of the substances. Data present the mean +/- standard error of 6 experiments in each case. The control R was 19.8 +/- 0.36 omega x cm2. The addition of spironolactone resulted in a reduction in the R, which became significant on both sides of the membrane within 10 minutes and remained significantly different thereafter. The maximum reduction of R (deltaR%) reached 24.8% +/- 2.3% (p < 0.01) apically and 26.3% +/- 3.2% (p < 0.01) basolaterally. Our data clearly show that spironolactone increases the permeability of visceral sheep peritoneum in a lasting manner. Increased peritoneal permeability could result in increased sodium removal, which has acknowledged beneficial effects both in patients undergoing peritoneal dialysis and in patients with heart failure. Further clinical studies investigating the effect of spironolactone on sodium removal in peritoneal dialysis are justified.

  3. Increased bactericidal/permeability increasing protein in patients with cirrhosis. (United States)

    Guerra-Ruiz, Armando; Casafont, Fernando; Cobo, Marta; Terán, Alvaro; de-la-Peña, Joaquín; Estebanez, Angel; Pons-Romero, Fernando


    High levels of endotoxin in patients with cirrhosis are thought to be responsible for the activation of tumour necrosis factor-alpha (TNF)-alpha-mediated pro-inflammatory pathways involved in haemodynamic alterations. Bactericidal/permeability increasing protein (BPI) is a protein found in neutrophils with endotoxin-binding and neutralization capacity. It is not known whether defective BPI production or release is present in cirrhosis. We investigated the levels of BPI in cirrhotic patients and its relation to other endotoxin-binding proteins and inflammatory markers. Plasmatic levels of BPI, lipopolysaccharide-binding protein, soluble CD14, TNF-alpha and BPI mRNA expression in neutrophils were determined in 130 patients and 30 healthy controls. The capacity of patients' plasma to inhibit lipopolysaccharide (LPS)-mediated TNF-alpha production by monocytes from healthy donors was assessed in vitro. Patients with cirrhosis exhibited an increase in BPI mRNA and plasma level of BPI when compared with healthy controls (P<0.05). Child C group displayed the highest frequency of patients with a high concentration of BPI. A positive correlation was found between TNF-alpha and plasma levels of BPI (P<0.01). High levels of BPI in plasma were able to significantly reduce in vitro TNF-alpha release by monocytes after a challenge with LPS (8.54 +/- 1.04 vs. 10.44 +/- 0.85 pg/ml, P=0.028). BPI is increased in cirrhotic patients, especially in those with more severe liver disease. The amount of BPI in the plasma correlated with the TNF-alpha level and was able to reduce LPS-mediated TNF production by monocytes. BPI possibly plays a regulatory role by antagonizing the pro-inflammatory mechanisms mediated by TNF-alpha.

  4. Systemic inflammation increases energy expenditure following pediatric cardiopulmonary bypass. (United States)

    Floh, Alejandro A; Nakada, Masayuki; La Rotta, Gustavo; Mah, Kandice; Herridge, Joann E; Van Arsdell, Glen; Schwartz, Steven M


    To examine the association between cardiopulmonary bypass-related systemic inflammation and resting energy expenditure in pediatric subjects following cardiac surgery. Single-center, prospective cohort study. Pediatric cardiac critical care unit in Toronto, Canada. Children with congenital heart disease undergoing cardiopulmonary bypass surgery. Resting energy expenditure was determined by indirect calorimetry and the modified Weir equation, using VO2 and VCO2 measured by in-line respiratory mass spectrometry. Measurements were taken at baseline and 6-hour intervals from separation from cardiopulmonary bypass for a maximum of 72 hours. Plasma interleukin-6, glucose delivery, feeding status, and cardiac output (calculated by Fick equation) were monitored at each resting energy expenditure measurement. We studied 111 subjects at a median (interquartile range) age of 5.3 months (0.8-10.5 mo), weighing 5.7 kg (3.9-8.1 kg), of whom 88% underwent biventricular repair. Resting energy expenditure decreased from 51 kcal/kg/d to 45 kcal/kg/d during the study period. Resting energy expenditure was positively associated with increased plasma interleukin-6 (estimate variable, 1.76; p = 0.001) and inversely associated with preoperative methylprednisolone use (estimate variable, -6.7; p = 0.003) even after accounting for other predictors. Increase in cardiac output was also associated (estimate variable, 13.7; p cardiopulmonary bypass surgery. It is directly associated with increased inflammation and higher cardiac output and inversely associated with anti-inflammatory strategies. Further studies are required to predict the appropriate caloric delivery in this cohort.

  5. Bovine Colostrum Supplementation During Running Training Increases Intestinal Permeability

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    Grant D. Brinkworth


    Full Text Available Endurance exercise training can increase intestinal permeability which may contribute to the development of gastrointestinal symptoms in some athletes. Bovine colostrum (BC supplementation reduces intestinal permeability induced by non-steroidal anti-inflammatory drugs. This study aimed to determine whether BC could also reduce intestinal permeability induced by endurance exercise. Thirty healthy adult males (25.0 ± 4.7 yr; mean ± SD completed eight weeks of running three times per week for 45 minutes at their lactate threshold while consuming 60 g/day of BC, whey protein (WP or control (CON. Intestinal permeability was assessed at baseline and after eight weeks by measuring the ratio of urinary lactulose (L and rhamnose (R excretion. After eight weeks the L/R ratio increased significantly more in volunteers consuming BC (251 ± 140% compared with WP (21 ± 35%, P < 0.05 and CON (−7 ± 13%, P < 0.02. The increase in intestinal permeability with BC may have been due to BC inducing greater leakiness of tight junctions between enterocytes or by increasing macromolecular transport as it does in neonatal gut. Further research should investigate the potential for BC to increase intestinal macromolecular transport in adults.

  6. Low serum sodium level during cardiopulmonary bypass predicts increased risk of postoperative stroke after coronary artery bypass graft surgery. (United States)

    Munoz, Elizandro; Briggs, Holly; Tolpin, Daniel A; Lee, Vei-Vei; Crane, Terry; Elayda, Macarthur A; Collard, Charles D; Pan, Wei


    Rapid decreases in serum sodium levels are associated with altered mental status, seizures, and coma. During cardiac surgery, serum sodium levels decrease rapidly when cardiopulmonary bypass is initiated because cardiopulmonary bypass causes hemodilution. However, whether this decrease influences neurologic outcome after cardiac surgery remains unclear. We investigated whether the average serum sodium level during cardiopulmonary bypass is independently predictive of postoperative stroke or 30-day all-cause mortality in patients who undergo primary coronary artery bypass grafting. In a single-institution, retrospective cohort of 2348 consecutive patients who underwent primary, isolated coronary artery bypass grafting, sequential multivariate logistic regression was performed to determine the threshold below which the average serum sodium level during cardiopulmonary bypass independently predicts postoperative stroke or early death. To further test the validity of this threshold and to control for selection bias, stepwise multivariate logistic regression was also performed on propensity score-matched patients (n = 924). An average serum sodium level less than 130 mEq/L during cardiopulmonary bypass was independently predictive of stroke, both in the entire study cohort (1.44% vs 2.92%; odds ratio, 2.09; 95% confidence interval, 1.1-4.1; P = .03) and in the propensity-matched patients (0.9% vs 3.0%; odds ratio, 4.1; 95% confidence interval, 1.3-13.0; P = .02). The average serum sodium level during cardiopulmonary bypass was not independently associated with early death, regardless of what threshold value was used. An average serum sodium level of less than 130 mEq/L during cardiopulmonary bypass is independently associated with an increased risk of postoperative stroke in patients who undergo primary coronary artery bypass grafting. Copyright © 2014 The American Association for Thoracic Surgery. Published by Mosby, Inc. All rights reserved.

  7. Store-operated calcium entry and increased endothelial cell permeability. (United States)

    Norwood, N; Moore, T M; Dean, D A; Bhattacharjee, R; Li, M; Stevens, T


    We hypothesized that myosin light chain kinase (MLCK) links calcium release to activation of store-operated calcium entry, which is important for control of the endothelial cell barrier. Acute inhibition of MLCK caused calcium release from inositol trisphosphate-sensitive calcium stores and prevented subsequent activation of store-operated calcium entry by thapsigargin, suggesting that MLCK serves as an important mechanism linking store depletion to activation of membrane calcium channels. Moreover, in voltage-clamped single rat pulmonary artery endothelial cells, thapsigargin activated an inward calcium current that was abolished by MLCK inhibition. F-actin disruption activated a calcium current, and F-actin stabilization eliminated the thapsigargin-induced current. Thapsigargin increased endothelial cell permeability in the presence, but not in the absence, of extracellular calcium, indicating the importance of calcium entry in decreasing barrier function. Although MLCK inhibition prevented thapsigargin from stimulating calcium entry, it did not prevent thapsigargin from increasing permeability. Rather, inhibition of MLCK activity increased permeability that was especially prominent in low extracellular calcium. In conclusion, MLCK links store depletion to activation of a store-operated calcium entry channel. However, inhibition of calcium entry by MLCK is not sufficient to prevent thapsigargin from increasing endothelial cell permeability.

  8. Turbofan Noise Reduction Associated With Increased Bypass Nozzle Flow (United States)

    Woodward, Richard P.; Hughes, Christopher E.


    An advanced 22-in. scale model turbofan, typical of a current-generation aircraft engine design by GE Aircraft Engines, was tested in NASA Glenn Research Center s 9- by 15- Foot Low-Speed Wind Tunnel to explore the far-field acoustic effects of an increased bypass nozzle area at simulated aircraft speeds of takeoff, approach, and landing. The wind-tunnel-scale model consisted of the bypass stage fan, stators, and nacelle (including the fan exit nozzle) of a typical turbofan. This fan-stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry, which acquired aeroacoustic results over a range of test conditions. A baseline nozzle was selected, and the nozzle area was chosen for maximum performance at sea-level conditions. Two additional nozzles were also tested--one with a 5.4-percent increase in nozzle area over the baseline nozzle (sized for design point conditions), corresponding to a 5-percent increase in fan weight flow, and another nozzle with a 10.9-percent increase in nozzle area over the baseline nozzle (sized for maximum weight flow at sea-level conditions), corresponding to a 7.5 percent increase in fan weight flow. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level reductions of 2 dB or more (left graph) while the stage adiabatic efficiency (right graph) and thrust (final graph) actually increased by several percentage points. These noise-reduction benefits were seen to include both rotor-interaction tones and broadband noise, and were evident throughout the range of measured sideline angles.

  9. The mycotoxin patulin increases colonic epithelial permeability in vitro. (United States)

    Mohan, H M; Collins, D; Maher, S; Walsh, E G; Winter, D C; O'Brien, P J; Brayden, D J; Baird, A W


    The gastrointestinal lumen is directly exposed to dietary contaminants, including patulin, a mycotoxin produced by moulds. Patulin is known to increase permeability across intestinal Caco-2 monolayers. This study aimed to determine the effect of patulin on permeability, ion transport and morphology in isolated rat colonic mucosae. Mucosal sheets were mounted in Ussing chambers and voltage clamped. Apical addition of patulin (100-500 μM) rapidly reduced transepithelial electrical resistance (TEER) and increased permeability to [(14)C] mannitol (2.9-fold). Patulin also inhibited carbachol-induced electrogenic chloride secretion and histological evidence of mucosal damage was observed. To examine potential mechanisms of action of patulin on colonic epithelial cells, high-content analysis of Caco-2 cells was performed and this novel, quantitative fluorescence-based approach confirmed its cytotoxic effects. With regard to time course, the cytotoxicity determined by high content analysis took longer than the almost immediate reduction of electrical resistance in isolated mucosal sheets. These data indicate patulin is not only cytotoxic to enterocytes but also has the capacity to directly alter permeability and ion transport in intact intestinal mucosae. These data corroborate and extend findings in intestinal cell culture monolayers, and further suggest that safety limits on consumption of patulin may be warranted. Copyright © 2012 Elsevier Ltd. All rights reserved.

  10. Cardiopulmonary bypass increases the risk of vasoplegic syndrome after coronary artery bypass grafting in patients with dialysis-dependent chronic renal failure. (United States)

    Hossne Junior, Nelson Américo; Miranda, Matheus; Monteiro, Marcus Rodrigo; Branco, João Nelson Rodrigues; Vargas, Guilherme Flora; Pestana, José Osmar Medina de Abreu; Gomes, Walter José


    Coronary artery bypass grafting is currently the best treatment for dialysis patients with multivessel coronary artery involvement. Vasoplegic syndrome of inflammatory etiology constitutes an important postoperative complication, with highly negative impact on prognosis. Considering that these patients have an intrinsic inflammatory response exacerbation, our goal was to evaluate the incidence and mortality of vasoplegic syndrome after myocardial revascularization in this group. A retrospective, single-center study of 50 consecutive and non-selected dialysis patients who underwent myocardial revascularization in a tertiary university hospital, from 2007 to 2012. The patients were divided into 2 groups, according to the use of cardiopulmonary bypass or not (off-pump coronary artery bypass). The incidence and mortality of vasoplegic syndrome were analyzed. The subgroup of vasoplegic patients was studied separately. There were no preoperative demographic differences between the cardiopulmonary bypass (n=20) and off-pump coronary artery bypass (n=30) group. Intraoperative data showed a greater number of distal coronary arteries anastomosis (2.8 vs. 1.8, Pcardiopulmonary bypass group. Vasoplegia incidence was statistically higher (P=0.0124) in the cardiopulmonary bypass group (30%) compared to the off-pump coronary artery bypass group (3%). Vasoplegia mortality was 50% in the cardiopulmonary bypass group and 0% in the off-pump coronary artery bypass group. The vasoplegic subgroup analysis showed no statistically significant clinical differences. Cardiopulmonary bypass increased the risk for developing postoperative vasoplegic syndrome after coronary artery bypass grafting in patients with dialysis-dependent chronic renal failure.

  11. Preoperative weight gain might increase risk of gastric bypass surgery. (United States)

    Istfan, Nawfal W; Anderson, Wendy A; Apovian, Caroline M; Hess, Donald T; Forse, R Armour


    Weight loss improves the cardiovascular and metabolic risk associated with obesity. However, insufficient data are available about the health effects of weight gain, separate from the obesity itself. We sought to determine whether the changes in body weight before open gastric bypass surgery (OGB) would have a significant effect on the immediate perioperative hospital course. A retrospective chart review of 100 consecutive patients was performed to examine the effects of co-morbidities and body weight changes in the immediate preoperative period on the hospital length of stay and the rate of admission to the surgical intensive care unit (SICU). Of our class III obese patients undergoing OGB, 95% had ≥1 co-morbid condition and an overall SICU admission rate of 18%. Compared with the patients with no perioperative SICU admission, the patients admitted to the SICU had a greater degree of insulin resistance (homeostatic model analysis-insulin resistance 10.8 ± 1.3 versus 5.9 ± 0.5, P = .001), greater serum triglyceride levels (225 ± 47 versus 143 ± 8 mg/dL, P = .003), and had gained more weight preoperatively (.52 ± .13 versus .06 ± .06 lb/wk, P = .003). The multivariate analyses showed that preoperative weight gain was a risk factor for a longer length of stay and more SICU admissions lasting ≥3 days, as were a diagnosis of sleep apnea and an elevated serum triglyceride concentration. The results of the present retrospective study suggest that weight gain increases the risk of perioperative SICU admission associated with OGB, independent of the body mass index. Sleep apnea and elevated serum triglyceride levels were also important determinants of perioperative morbidity. In view of the increasing epidemic of obesity and the popularity of bariatric surgical procedures, we propose that additional clinical and metabolic research focusing on the understanding of the complex relationship among obesity, positive energy balance, weight gain, and perioperative

  12. Increasing the permeability of Escherichia coli using MAC13243

    DEFF Research Database (Denmark)

    Muheim, Claudio; Götzke, Hansjörg; Eriksson, Anna U.


    The outer membrane of gram-negative bacteria is a permeability barrier that prevents the efficient uptake of molecules with large scaffolds. As a consequence, a number of antibiotic classes are ineffective against gram-negative strains. Herein we carried out a high throughput screen for small mol...... molecules that make the outer membrane of Escherichia coli more permeable. We identified MAC13243, an inhibitor of the periplasmic chaperone LolA that traffics lipoproteins from the inner to the outer membrane. We observed that cells were (1) more permeable to the fluorescent probe 1-N......-phenylnapthylamine, and (2) more susceptible to large-scaffold antibiotics when sub-inhibitory concentrations of MAC13243 were used. To exclude the possibility that the permeability was caused by an off-target effect, we genetically reconstructed the MAC13243-phenotype by depleting LolA levels using the CRISPRi system....

  13. Cardiopulmonary bypass increases the risk of vasoplegic syndrome after coronary artery bypass grafting in patients with dialysis-dependent chronic renal failure

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    Nelson Américo Hossne Junior


    Full Text Available Abstract Objective: Coronary artery bypass grafting is currently the best treatment for dialysis patients with multivessel coronary artery involvement. Vasoplegic syndrome of inflammatory etiology constitutes an important postoperative complication, with highly negative impact on prognosis. Considering that these patients have an intrinsic inflammatory response exacerbation, our goal was to evaluate the incidence and mortality of vasoplegic syndrome after myocardial revascularization in this group. Methods: A retrospective, single-center study of 50 consecutive and non-selected dialysis patients who underwent myocardial revascularization in a tertiary university hospital, from 2007 to 2012. The patients were divided into 2 groups, according to the use of cardiopulmonary bypass or not (off-pump coronary artery bypass. The incidence and mortality of vasoplegic syndrome were analyzed. The subgroup of vasoplegic patients was studied separately. Results: There were no preoperative demographic differences between the cardiopulmonary bypass (n=20 and off-pump coronary artery bypass (n=30 group. Intraoperative data showed a greater number of distal coronary arteries anastomosis (2.8 vs. 1.8, P<0.0001 and higher transfusion rates (65% vs. 23%, P=0.008 in the cardiopulmonary bypass group. Vasoplegia incidence was statistically higher (P=0.0124 in the cardiopulmonary bypass group (30% compared to the off-pump coronary artery bypass group (3%. Vasoplegia mortality was 50% in the cardiopulmonary bypass group and 0% in the off-pump coronary artery bypass group. The vasoplegic subgroup analysis showed no statistically significant clinical differences. Conclusion: Cardiopulmonary bypass increased the risk for developing postoperative vasoplegic syndrome after coronary artery bypass grafting in patients with dialysis-dependent chronic renal failure.

  14. Bactericidal Permeability-Increasing Proteins Shape Host-Microbe Interactions

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    Fangmin Chen


    Full Text Available We characterized bactericidal permeability-increasing proteins (BPIs of the squid Euprymna scolopes, EsBPI2 and EsBPI4. They have molecular characteristics typical of other animal BPIs, are closely related to one another, and nest phylogenetically among invertebrate BPIs. Purified EsBPIs had antimicrobial activity against the squid’s symbiont, Vibrio fischeri, which colonizes light organ crypt epithelia. Activity of both proteins was abrogated by heat treatment and coincubation with specific antibodies. Pretreatment under acidic conditions similar to those during symbiosis initiation rendered V. fischeri more resistant to the antimicrobial activity of the proteins. Immunocytochemistry localized EsBPIs to the symbiotic organ and other epithelial surfaces interacting with ambient seawater. The proteins differed in intracellular distribution. Further, whereas EsBPI4 was restricted to epithelia, EsBPI2 also occurred in blood and in a transient juvenile organ that mediates hatching. The data provide evidence that these BPIs play different defensive roles early in the life of E. scolopes, modulating interactions with the symbiont.

  15. A photorespiratory bypass increases plant growth and seed yield in biofuel crop Camelina sativa. (United States)

    Dalal, Jyoti; Lopez, Harry; Vasani, Naresh B; Hu, Zhaohui; Swift, Jennifer E; Yalamanchili, Roopa; Dvora, Mia; Lin, Xiuli; Xie, Deyu; Qu, Rongda; Sederoff, Heike W


    Camelina sativa is an oilseed crop with great potential for biofuel production on marginal land. The seed oil from camelina has been converted to jet fuel and improved fuel efficiency in commercial and military test flights. Hydrogenation-derived renewable diesel from camelina is environmentally superior to that from canola due to lower agricultural inputs, and the seed meal is FDA approved for animal consumption. However, relatively low yield makes its farming less profitable. Our study is aimed at increasing camelina seed yield by reducing carbon loss from photorespiration via a photorespiratory bypass. Genes encoding three enzymes of the Escherichia coli glycolate catabolic pathway were introduced: glycolate dehydrogenase (GDH), glyoxylate carboxyligase (GCL) and tartronic semialdehyde reductase (TSR). These enzymes compete for the photorespiratory substrate, glycolate, convert it to glycerate within the chloroplasts, and reduce photorespiration. As a by-product of the reaction, CO2 is released in the chloroplast, which increases photosynthesis. Camelina plants were transformed with either partial bypass (GDH), or full bypass (GDH, GCL and TSR) genes. Transgenic plants were evaluated for physiological and metabolic traits. Expressing the photorespiratory bypass genes in camelina reduced photorespiration and increased photosynthesis in both partial and full bypass expressing lines. Expression of partial bypass increased seed yield by 50-57 %, while expression of full bypass increased seed yield by 57-73 %, with no loss in seed quality. The transgenic plants also showed increased vegetative biomass and faster development; they flowered, set seed and reached seed maturity about 1 week earlier than WT. At the transcriptional level, transgenic plants showed differential expression in categories such as respiration, amino acid biosynthesis and fatty acid metabolism. The increased growth of the bypass transgenics compared to WT was only observed in ambient or low CO

  16. Conventional hemofiltration during cardiopulmonary bypass increases the serum lactate level in adult cardiac surgery

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    Rabie Soliman


    Full Text Available Objective: To evaluate the effect of hemofiltration during cardiopulmonary bypass on lactate level in adult patients who underwent cardiac surgery. Design: An observational study. Setting: Prince Sultan cardiac center, Riyadh, Saudi Arabia. Participants: The study included 283 patients classified into two groups: Hemofiltration group (n=138, hemofiltration was done during CPB. Control group (n = 145, patients without hemofiltration. Interventions: Hemofiltration during cardiopulmonary bypass. Measurements and Main Results: Monitors included hematocrit, lactate levels, mixed venous oxygen saturation, amount of fluid removal during hemofiltration and urine output. The lactate elevated in group H than group C (P < 0.05, and the PH showed metabolic acidosis in group H (P < 0.05. The mixed venous oxygen saturation decreased in group H than group C (P < 0.05. The number of transfused packed red blood cells was lower in group H than group C (P < 0.05. The hematocrit was higher in group H than group C (P < 0.05. The urine output was lower in group H than group C (P < 0.05. Conclusions: Hemofiltration during cardiopulmonary bypass leads to hemoconcentration, elevated lactate level and increased inotropic support. There are some recommendations for hemofiltration: First; Hemofiltration should be limited for patients with impaired renal function, positive fluid balance, reduced response to diuretics or prolonged bypass time more than 2 hours. Second; Minimal amount of fluids should be administered to maintain adequate cardiac output and reduction of priming volumes is preferable to maintain controlled hemodilution. Third; it should be done before weaning of or after cardiopulmonary bypass and not during the whole time of cardiopulmonary bypass.

  17. On the Relation Between Transient Elastic Softening and Permeability Increase in fractured shale and granite (United States)

    Riviere, J.; Madara, B.; Elsworth, D.; Johnson, P. A.; Marone, C.


    Dynamic stressing of rocks is known to transiently increase permeability, and has potential application to improve the efficiency of geothermal energy production and oil/gas recovery. At larger scale, teleseismic waves have been observed to transiently increase permeability of aquifer systems. Seismic waves are also known to transiently decrease elastic moduli near fault zones. However, it remains unclear which parameters control the magnitude of permeability increase and how this magnitude can be predicted. We report on laboratory studies that monitor both permeability evolution and elastic properties in fractured granite and shale. We use L-shaped samples that are loaded with triaxial stresses of order 10 MPa and fractured in a triaxial cell. Deionized water is forced to flow along the resulting fracture path by applying a differential pore pressure along the shear direction. Dynamic stressing is applied via pore pressure or normal stress oscillations (20 s-duration, up to 1 Hz-frequency and 1 MPa-amplitude), while measuring flow rates and elastic wave velocities. Our observations enable transient increases in permeability to be determined following dynamic stressing and constrained via measurements of ultrasonic velocity. In particular, these preliminary results are discussed with former results suggesting that permeability enhancement is dictated by flow rate.

  18. Leukotriene D4 increases pulmonary vascular permeability and pressure by different mechanisms in the rabbit. (United States)

    Farrukh, I S; Sciuto, A M; Spannhake, E W; Gurtner, G H; Michael, J R


    We designed experiments to define the effects of leukotriene D4 (LTD4) in the rabbit lung and to determine whether or not these effects were due to the synthesis of cyclooxygenase products. Infusion of LTD4 (0.01, 0.03, and 0.10 microgram) into the rabbit pulmonary vasculature caused a dose-related increase in pulmonary arterial pressure and tracheal pressure. Pretreatment with FPL 55712 (38 microM), a leukotriene receptor antagonist, or indomethacin (10 micrograms/ml of perfusate) completely prevented the increase in tracheal and pulmonary arterial pressure. We also studied the effect of LTD4 on pulmonary vascular permeability by measuring lung weight gain at 4 levels of left atrial pressures (0, 5, 10, and 15 mmHg). Leukotriene D4 increased lung weight gain at all levels of left atrial pressure compared with that in the control group. Pretreatment with FPL 55712 completely inhibited the increase in vascular permeability caused by LTD4. Although pretreatment with indomethacin blocked the increase in tracheal and vascular pressure caused by LTD4, it did not prevent the increase in vascular permeability. We conclude that in the rabbit, LTD4 increases tracheal pressure, pulmonary arterial pressure, and pulmonary vascular permeability. Leukotriene D4 increases tracheal and pulmonary arterial pressure by stimulating the synthesis of cyclooxygenase products, and it increases vascular permeability through a mechanism that does not require the synthesis of cyclooxygenase products.

  19. Transient and sustained increases in glomerular permeability following ANP infusion in rats. (United States)

    Axelsson, Josefin; Rippe, Anna; Rippe, Bengt


    The present study was performed to investigate the effects of systemic atrial natriuretic peptide (ANP) infusion on the glomerular permeability to macromolecules in rats. In anesthetized Wistar rats (250-280 g), the left urether was cannulated for urine collection while simultaneously blood access was achieved. Rats were continuously infused intravenously with ANP [30 ng·kg(-1)·min(-1) (Lo-ANP; n=8) or 800 ng·kg(-1)·min(-1) (Hi-ANP; n=10)] or 0.9% NaCl (SHAM; n=16), respectively, and with polydisperse FITC-Ficoll-70/400 (molecular radius 13-90 Å) and 51Cr-EDTA for 2 h. Plasma and urine samples were taken at 5, 15, 30, 60, and 120 min of ANP infusion and analyzed by high-performance size-exclusion chromatography (HPLC) for determination of glomerular sieving coefficients (θ) for Ficoll. GFR was also assessed (51Cr-EDTA). In Hi-ANP, there was a rapid (within 5 min), but bimodal, increase in glomerular permeability. θ to high-molecular-weight Ficoll thus reached a maximum at 15 min, after which θ returned to near control at 30 min, to again increase moderately at 60 and 120 min. In Lo-ANP, there was also a rapid, reversible increase in glomerular θ, returning to near control at 30 min, followed by just a tendency of a sustained increase in permeability, but with a significant increase in "large-pore" radius. In conclusion, in Hi-ANP there was a rapid increase in glomerular permeability, with an early, partly reversible permeability peak, followed by a (moderate) sustained increase in permeability. In Lo-ANP animals, only the initial permeability peak was evident. In both Lo-ANP and Hi-ANP, the glomerular sieving pattern observed was found to mainly reflect an increase in the number and radius of large pores in the glomerular filter.

  20. Human uremic plasma increases microvascular permeability to water and proteins in vivo. (United States)

    Harper, Steven J; Tomson, Charles R V; Bates, David O


    The risk of cardiovascular disease is significantly higher in patients with long-term uremia than in otherwise healthy adults. This is true even before patients proceed to dialysis, but the reason why cardiovascular risk is increased is unknown. Transvascular transport of lipids and other macromolecules in both large vessels and the microcirculation has been implicated in generation of cardiovascular disease. To determine whether patients with long-term uremia have circulating factors that promote increased vascular permeability, we measured the effect of perfusing microvessels with uremic plasma in a non-mammalian model of vascular permeability measurement. Perfusion of frog mesenteric microvessels with dialyzed normal plasma did not result in an increase in either hydraulic conductivity (Lp, permeability of the vessel wall to water) or oncotic reflection coefficient (sigma, permeability to macromolecules, particularly proteins). Perfusion with dialyzed uremic plasma resulted in a very significant increase in vascular permeability to both water (Lp increased 8.8-fold from 4.1 to 36.4 x 10(-7) cm x s(-1) cm H2O(-1)) and proteins (sigma reduced from 0.93 to 0.53). These results suggest that one or more circulating macromolecules in uremic plasma are able to increase transvascular solute and fluid flux, and may underlie the increased cardiovascular risk found in these patients.

  1. Plasma from patients with HELLP syndrome increases blood-brain barrier permeability. (United States)

    Wallace, Kedra; Tremble, Sarah M; Owens, Michelle Y; Morris, Rachael; Cipolla, Marilyn J


    Circulating inflammatory factors and endothelial dysfunction have been proposed to contribute to the pathophysiology of hemolysis, elevated liver enzymes, and low platelet count (HELLP) syndrome. To date, the occurrence of neurological complications in these women has been reported, but few studies have examined whether impairment in blood-brain barrier (BBB) permeability or cerebrovascular reactivity is present in women having HELLP syndrome. We hypothesized that plasma from women with HELLP syndrome causes increased BBB permeability and cerebrovascular dysfunction. Posterior cerebral arteries from female nonpregnant rats were perfused with 20% serum from women with normal pregnancies (n = 5) or women with HELLP syndrome (n = 5), and BBB permeability and vascular reactivity were compared. Plasma from women with HELLP syndrome increased BBB permeability while not changing myogenic tone and reactivity to pressure. Addition of the nitric oxide (NO) synthase inhibitor N(ω)-nitro-L-arginine methyl ester caused constriction of arteries that was not different with the different plasmas nor was dilation to the NO donor sodium nitroprusside different between the 2 groups. However, dilation to the small- and intermediate-conductance, calcium-activated potassium channel activator NS309 was decreased in vessels exposed to HELLP plasma. Thus, increased BBB permeability in response to HELLP plasma was associated with selective endothelial dysfunction. © The Author(s) 2014.

  2. Maintenance of superior mesenteric arterial perfusion prevents increased intestinal mucosal permeability in endotoxic pigs

    Energy Technology Data Exchange (ETDEWEB)

    Fink, M.P.; Kaups, K.L.; Wang, H.L.; Rothschild, H.R. (Department of Surgery, University of Massachusetts Medical Center, Worcester (USA))


    Lipopolysaccharide increases intestinal mucosal permeability to hydrophilic compounds such as chromium 51-labeled edetate (51Cr-EDTA). The authors sought to determine whether this phenomenon is partly mediated by lipopolysaccharide-induced mesenteric hypoperfusion. They assessed permeability in an isolated segment of ileum by measuring plasma-to-lumen clearances (C) for two probes, 51Cr-EDTA and urea, and expressing the results as a ratio (CEDTA/CUREA). In control pigs (n = 6) resuscitated with Ringer's lactate (RL), mucosal permeability was unchanged during the 210-minute period of observation. In pigs (n = 7) infused with lipopolysaccharide (50 micrograms/kg) and similarly resuscitated with RL, mesenteric perfusion (Qsma) decreased significantly and permeability increased progressively and significantly. When endotoxic pigs (n = 6) were resuscitated with a regimen (RL plus hetastarch plus dobutamine) that preserved normal Qsma, lipopolysaccharide-induced mucosal hyperpermeability was prevented. Resuscitation of endotoxic pigs (n = 6) with RL plus hetastarch provided intermediate protection against both mesenteric hypoperfusion and increased permeability. These data suggest that diminished Qsma contributes to impaired ileal mucosal barrier function in experimental endotoxicosis.

  3. Matrix metalloproteinases 2 and 9 increase permeability of sheep pleura in vitro. (United States)

    Apostolidou, Eleni; Paraskeva, Efrosyni; Gourgoulianis, Konstantinos; Molyvdas, Paschalis-Adam; Hatzoglou, Chrissi


    Matrix metalloproteinases (MMPs) 2 and 9 are two gelatinase members which have been found elevated in exudative pleural effusions. In endothelial cells these MMPs increase paracellular permeability via the disruption of tight junction (TJ) proteins occludin and claudin. In the present study it was investigated if MMP2 and MMP9 alter permeability properties of the pleura tissue by degradation of TJ proteins in pleural mesothelium. In the present study the transmesothelial resistance (RTM) of sheep pleura tissue was recorded in Ussing chambers after the addition of MMP2 or MMP9. Both enzymes reduced RTM of the pleura, implying an increase in pleural permeability. The localization and expression of TJ proteins, occludin and claudin-1, were assessed after incubation with MMPs by indirect immunofluorescence and western blot analysis. Our results revealed that incubation with MMPs did not alter neither proteins localization at cell periphery nor their expression. MMP2 and MMP9 increase the permeability of sheep pleura and this finding suggests a role for MMPs in pleural fluid formation. Tight junction proteins remain intact after incubation with MMPs, contrary to previous studies which have shown TJ degradation by MMPs. Probably MMP2 and MMP9 augment pleural permeability via other mechanisms.

  4. Matrix metalloproteinases 2 and 9 increase permeability of sheep pleura in vitro

    Directory of Open Access Journals (Sweden)

    Apostolidou Eleni


    Full Text Available Abstract Background Matrix metalloproteinases (MMPs 2 and 9 are two gelatinase members which have been found elevated in exudative pleural effusions. In endothelial cells these MMPs increase paracellular permeability via the disruption of tight junction (TJ proteins occludin and claudin. In the present study it was investigated if MMP2 and MMP9 alter permeability properties of the pleura tissue by degradation of TJ proteins in pleural mesothelium. Results In the present study the transmesothelial resistance (RTM of sheep pleura tissue was recorded in Ussing chambers after the addition of MMP2 or MMP9. Both enzymes reduced RTM of the pleura, implying an increase in pleural permeability. The localization and expression of TJ proteins, occludin and claudin-1, were assessed after incubation with MMPs by indirect immunofluorescence and western blot analysis. Our results revealed that incubation with MMPs did not alter neither proteins localization at cell periphery nor their expression. Conclusions MMP2 and MMP9 increase the permeability of sheep pleura and this finding suggests a role for MMPs in pleural fluid formation. Tight junction proteins remain intact after incubation with MMPs, contrary to previous studies which have shown TJ degradation by MMPs. Probably MMP2 and MMP9 augment pleural permeability via other mechanisms.

  5. Rural Patients With Severe Sepsis or Septic Shock Who Bypass Rural Hospitals Have Increased Mortality: An Instrumental Variables Approach. (United States)

    Mohr, Nicholas M; Harland, Karisa K; Shane, Dan M; Ahmed, Azeemuddin; Fuller, Brian M; Ward, Marcia M; Torner, James C


    To identify factors associated with rural sepsis patients' bypassing rural emergency departments to seek emergency care in larger hospitals, and to measure the association between rural hospital bypass and sepsis survival. Observational cohort study. Emergency departments of a rural Midwestern state. All adults treated with severe sepsis or septic shock between 2005 and 2014, using administrative claims data. Patients bypassing local rural hospitals to seek care in larger hospitals. A total of 13,461 patients were included, and only 5.4% (n = 731) bypassed a rural hospital for their emergency department care. Patients who initially chose a top-decile sepsis volume hospital were younger (64.7 vs 72.7 yr; p instrumental variables approach, rural hospital bypass was associated with a 5.6% increase (95% CI, 2.2-8.9%) in mortality. Most rural patients with sepsis seek care in local emergency departments, but demographic and disease-oriented factors are associated with rural hospital bypass. Rural hospital bypass is independently associated with increased mortality.

  6. Artemisinin permeability via Caco-2 cells increases after simulated digestion of Artemisia annua leaves. (United States)

    Desrosiers, Matthew R; Weathers, Pamela J


    Artemisia annua has been used for > 2000yrs to treat fever and is more recently known for producing the important antimalarial drug, artemisinin. Artemisinin combination therapies (ACTs) are effective for treating malaria, but are often unavailable to those in need. Dried leaves of A. annua (DLA) have recently been studied as a cost effective alternative to traditional ACTs. DLA was shown to dramatically increase oral bioavailability compared to pure artemisinin, so more investigation into the mechanisms causing this increased bioavailability is needed. In this study, we used a simulated digestion system coupled with Caco-2 cell permeability assays to investigate the intestinal permeability of DLA compared to pure artemisinin. We also determined the effects of different phytochemicals (7 flavonoids, 3 monoterpenes, 2 phenolic acids, scopoletin and inulin) and the cytochrome P450 isoform CYP3A4 on artemisinin intestinal permeability. Artemisinin permeability, when delivered as digested DLA, significantly increased by 37% (Papp = 8.03 × 10-5cms-1) compared to pure artemisinin (Papp = 5.03 × 10-5cms-1). However, none of the phytochemicals tested or CYP3A4 had any significant effect on the intestinal permeability of artemisinin. We also showed that essential oil derived from A. annua negatively affected the intestinal permeability of artemisinin, but only after simulated digestion. Finally, we showed that A. annua essential oil reduced the transepithelial electrical resistance of Caco-2 monolayers, but only in the presence of bile. Although also reduced by essential oils, artemisinin Papp subsequently recovered in the presence of plant matrix. These results shed light on the mechanisms by which DLA enhances the oral bioavailability of artemisinin. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. Increased permeability to polyethylene glycol 4000 in rabbits with experimental colitis

    Energy Technology Data Exchange (ETDEWEB)

    Seidman, E.G.; Hanson, D.G.; Walker, W.A.


    Little information is available regarding colonic permeability to macromolecules in health or disease states. In vivo permeability of rabbit colon to (/sup 14/C)polyethylene glycol 4000 (/sup 14/C-PEG) was examined in the presence of immune complex-mediated experimental colitis and compared with that of partially treated (control) and normal rabbits. Permeability was assessed by urinary /sup 14/C-PEG excretion after intrarectal administration of 0.1 mM solution of /sup 14/C-PEG (1 ml/kg, 7.5 X 10(6) cpm/ml). Experimental colitis greatly increased colonic permeability (p less than 0.001 in two-way analysis of variance) compared with control and normal groups (2.06% +/- 0.19%, 0.14% +/- 0.04%, and 0.01% +/- 0.004%, respectively, of rectally administered counts). Gel diffusion chromatography showed that absorbed /sup 14/C-PEG was excreted into urine unchanged, demonstrating its applicability as an inert, nonmetabolizable macromolecular probe. Urinary clearance after mesenteric vein administration of /sup 14/C-PEG was similar in normal animals and animals with colitis, implicating colonic absorption as the source of the group differences. Postmortem histology confirmed the acute colitis lesions in the experimental group. These findings support the hypothesis that nonspecific colonic inflammation is associated with significant alterations of mucosal permeability.

  8. Impaired oxygenation and increased hemolysis after cardiopulmonary bypass in patients with glucose-6-phosphate dehydrogenase deficiency. (United States)

    Gerrah, Rabin; Shargal, Yaron; Elami, Amir


    The purpose of this study was to determine whether the damaging effects of cardiopulmonary bypass, ischemia, and reperfusion would be more pronounced in patients with glucose-6-phosphate dehydrogenase deficiency undergoing cardiac surgery. Forty-two patients with glucose-6-phosphate dehydrogenase deficiency underwent open heart procedures using cardiopulmonary bypass. This group was matched with a control group of identical size for comparison of operative course and postoperative outcome. The perioperative variables were compared between the two groups using univariate and multivariate analysis. The duration of ventilation after the operation was significantly longer in the glucose-6-phosphate dehydrogenase-deficient group (13.7 +/- 7.6 hours versus 7.7 +/- 2.8 hours; p < 0.0001). Minimal value of arterial oxygen tension was lower in patients with glucose-6-phosphate dehydrogenase deficiency (66 +/- 12 mm Hg versus 85 +/- 14 mm Hg; p < 0.0001), and more cases of hypoxia (arterial oxygen tension < 60 mm Hg) were found in this group (11 versus 1; p = 0.001). Compared with the control group, patients with glucose-6-phosphate dehydrogenase deficiency had significantly elevated hemolytic indices expressed by bilirubin levels (26 +/- 10 mmol/L versus 17 +/- 6.7 mmol/L; p < 0.0001) and lactic dehydrogenase levels (970 +/- 496 U/L versus 505 +/- 195 U/L; p < 0.0001). They also required significantly more blood transfusion perioperatively (1.9 +/- 1.4 packed cell units/patient versus 0.8 +/- 1.0 packed cell units/patient; p = 0.0001). Patients with glucose-6-phosphate dehydrogenase deficiency who are undergoing cardiac surgery may have a more complicated course with a longer ventilation time, more hypoxia, increased hemolysis, and a need for more blood transfusion. Because this difference may be caused by subnormal free radical deactivation, strategies that minimize bypass in general and free radicals specifically may be beneficial.

  9. Nicotinamide and its metabolite N-methylnicotinamide increase skin vascular permeability in rats. (United States)

    Pietrzak, L; Mogielnicki, A; Buczko, W


    It has been suggested that topically applied nicotinamide and its metabolite N-methylnicotinamide (NMN(+)) might be useful agents for treatment of dermatological disorders such as acne vulgaris and rosacea. This study aimed to find out if the mechanism of these therapeutic effects depends on their vascular effects, by investigating if nicotinamide and NMN(+) are able to influence vascular permeability of the vessels in the skin on the back of Wistar rats. A dose-dependent increase in vascular permeability was seen in rats treated intradermally with nicotinamide and NMN(+). Interestingly, a significantly stronger effect of NMN(+) compared with nicotinamide was evident. Increased vascular permeability in rats treated with 0.5% NMN(+) ointment was seen. Moreover, indomethacin, a cyclo-oxygenase 1 and 2 inhibitor and N(G)-nitro-L-arginine methyl ester (L-NAME), a nitric oxide (NO) synthase inhibitor, reduced the observed effects of nicotinamide and NMN(+). This study provides direct in vivo evidence that nicotinamide and its metabolite NMN(+) increase skin vascular permeability in rats by a mechanism that may involve NO and prostaglandins.

  10. Suppressions of serotonin-induced increased vascular permeability and leukocyte infiltration by Bixa orellana leaf extract. (United States)

    Yong, Yoke Keong; Sulaiman, NurShahira; Hakim, Muhammad Nazrul; Lian, Gwendoline Ee Cheng; Zakaria, Zainul Amirudin; Othman, Fauziah; Ahmad, Zuraini


    The aim of the present study was to evaluate the anti-inflammatory activities of aqueous extract of Bixa orellana (AEBO) leaves and its possible mechanisms in animal models. The anti-inflammatory activity of the extract was evaluated using serotonin-induced rat paw edema, increased peritoneal vascular permeability, and leukocyte infiltrations in an air-pouch model. Nitric oxide (NO), indicated by the sum of nitrites and nitrates, and vascular growth endothelial growth factor (VEGF) were measured in paw tissues of rats to determine their involvement in the regulation of increased permeability. Pretreatments with AEBO (50 and 150 mg kg⁻¹) prior to serotonin inductions resulted in maximum inhibitions of 56.2% of paw volume, 45.7% of Evans blue dye leakage in the peritoneal vascular permeability model, and 83.9% of leukocyte infiltration in the air-pouch model. 57.2% maximum inhibition of NO and 27% of VEGF formations in rats' paws were observed with AEBO at the dose of 150 mg kg⁻¹. Pharmacological screening of the extract showed significant (P < 0.05) anti-inflammatory activity, indicated by the suppressions of increased vascular permeability and leukocyte infiltration. The inhibitions of these inflammatory events are probably mediated via inhibition of NO and VEGF formation and release.

  11. Suppressions of Serotonin-Induced Increased Vascular Permeability and Leukocyte Infiltration by Bixa orellana Leaf Extract

    Directory of Open Access Journals (Sweden)

    Yoke Keong Yong


    Full Text Available The aim of the present study was to evaluate the anti-inflammatory activities of aqueous extract of Bixa orellana (AEBO leaves and its possible mechanisms in animal models. The anti-inflammatory activity of the extract was evaluated using serotonin-induced rat paw edema, increased peritoneal vascular permeability, and leukocyte infiltrations in an air-pouch model. Nitric oxide (NO, indicated by the sum of nitrites and nitrates, and vascular growth endothelial growth factor (VEGF were measured in paw tissues of rats to determine their involvement in the regulation of increased permeability. Pretreatments with AEBO (50 and 150 mg kg−1 prior to serotonin inductions resulted in maximum inhibitions of 56.2% of paw volume, 45.7% of Evans blue dye leakage in the peritoneal vascular permeability model, and 83.9% of leukocyte infiltration in the air-pouch model. 57.2% maximum inhibition of NO and 27% of VEGF formations in rats’ paws were observed with AEBO at the dose of 150 mg kg−1. Pharmacological screening of the extract showed significant (P<0.05 anti-inflammatory activity, indicated by the suppressions of increased vascular permeability and leukocyte infiltration. The inhibitions of these inflammatory events are probably mediated via inhibition of NO and VEGF formation and release.

  12. Dopexamine increases internal mammary artery blood flow following coronary artery bypass grafting.

    LENUS (Irish Health Repository)

    Flynn, Michael J


    OBJECTIVE: Vasoactive agents and inotropes influence conduit-coronary blood flow following coronary artery bypass grafting (CABG). It was hypothesized that dopexamine hydrochloride, a dopamine A-1 (DA-1) and beta(2) agonist would increase conduit-coronary blood flow. A prospective randomized double blind clinical trial was carried out to test this hypothesis. DA-1 receptors have previously been localized to human left ventricle. METHODS: Twenty-six American Society of Anaesthesiology class 2-3 elective coronary artery bypass graft patients who did not require inotropic support on separation from cardiopulmonary bypass (CPB) were studied. According to a randomized allocation patients received either dopexamine (1 microg\\/kg per min) or placebo (saline) by intravenous infusion for 15 min. Immediately prior to and at 5,10 and 15 min of infusion, blood flow through the internal mammary and vein grafts (Transit time flow probes, Transonic Ltd.), heart rate, cardiac index, mean arterial pressure and pulmonary haemodynamics were noted. The data were analysed using multivariate analysis of variance. RESULTS: Low-dose dopexamine (1 microg\\/kg per min) caused a significant increase in mammary graft blood flow compared to placebo at 15 min of infusion (P=0.028, dopexamine group left internal mammary artery (LIMA) flow of 43.3+\\/-14.2 ml\\/min, placebo group LIMA flow at 26.1+\\/-16.3 ml\\/min). Dopexamine recipients demonstrated a non-significant trend to increased saphenous vein graft flow (P=0.059). Increased heart rate was the only haemodynamic change induced by dopexamine (P=0.004, dopexamine group at 85.2+\\/-9.6 beats\\/min and placebo group at 71.1+\\/-7.6 beats\\/min after 15 min of infusion). CONCLUSION: This study demonstrates that administration of dopexamine (1 microg\\/kg per min) was associated with a significant increase in internal mammary artery graft blood flow with mild increase in heart rate being the only haemodynamic change. Low-dose dopexamine may

  13. Gadolinium prevents high airway pressure-induced permeability increases in isolated rat lungs. (United States)

    Parker, J C; Ivey, C L; Tucker, J A


    To determine the initial signaling event in the vascular permeability increase after high airway pressure injury, we compared groups of lungs ventilated at different peak inflation pressures (PIPs) with (gadolinium group) and without (control group) infusion of 20 microM gadolinium chloride, an inhibitor of endothelial stretch-activated cation channels. Microvascular permeability was assessed by using the capillary filtration coefficient (Kfc), a measure of capillary hydraulic conductivity. Kfc was measured after ventilation for 30-min periods with 7, 20, and 30 cmH2O PIP with 3 cmH2O positive end-expiratory pressure and with 35 cmH2O PIP with 8 cmH2O positive end-expiratory pressure. In control lungs, Kfc increased significantly to 1.8 and 3.7 times baseline after 30 and 35 cmH2O PIP, respectively. In the gadolinium group, Kfc was unchanged from baseline (0.060 +/- 0.010 ml . min-1 . cmH2O-1 . 100 g-1) after any PIP ventilation period. Pulmonary vascular resistance increased significantly from baseline in both groups before the last Kfc measurement but was not different between groups. These results suggest that microvascular permeability is actively modulated by a cellular response to mechanical injury and that stretch-activated cation channels may initiate this response through increases in intracellular calcium concentration.

  14. Increase in Levels of BDNF is Associated with Inflammation and Oxidative Stress during Cardiopulmonary Bypass (United States)

    Amoureux, Sébastien; Sicard, Pierre; Korandji, Claudia; Borey, Angélique; Benkhadra, Salima; Sequeira-Le Grand, Anabelle; Vergely, Catherine; Girard, Claude; Rochette, Luc


    Cardiopulmonary Bypass (CPB) is thought to generate reactive oxygen species associated with a systemic inflammation and neurotrophins seem to be involved in cardiovascular inflammatory reactions. The aim of this study was to determine the impact of CPB on plasma neurotrophins levels and to appreciate the links existing between inflammation, oxidative stress and neurotrophins. Blood samples were taken from 27 patients undergoing cardiac surgery: before CPB, during ischemia and at reperfusion under CPB. Oxidative stress was evaluated using an Electron Spin Resonance technique by superoxide detection, and antioxidant defences by measurement of Endogenous Peroxidase Activity (EPA). The evolution of two neurotrophins: Brain Derived Neurotrophic Factor (BDNF) and Nerve Growth Factor (NGF) was assessed with an ELISA method. An inflammatory index was determined by a multiplex flow cytometry method. The inflammatory index showed that MCP-1, P-selectin, t-PA and interleukins 6, 8 and 10 levels increased during CPB (peffect during CPB. PMID:23675091

  15. Increase in the permeability of tonoplast of garlic (Allium sativum) by monocarboxylic acids. (United States)

    Bai, Bing; Li, Lei; Hu, Xiaosong; Wang, Zhengfu; Zhao, Guanghua


    Immersion of intact aged garlic (Allium sativum) cloves in a series of 5% weak organic monocarboxylate solutions (pH 2.0) resulted in green color formation. No color was formed upon treatment with other weak organic acids, such as citric and malic acids, and the inorganic hydrochloric acid under the same conditions. To understand the significance of monocarboxylic acids and their differing function from that of other acids, acetic acid was compared with organic acids citric and malic and the inorganic hydrochloric acid. The effects of these acids on the permeability of plasma and intracellular membrane of garlic cells were measured by conductivity, light microscopy, and transmission electron microscopy. Except for hydrochloric acid, treatment of garlic with all three organic acids greatly increased the relative conductivity of their respective pickling solutions, indicating that all tested organic acids increased the permeability of plasma membrane. Moreover, a pickling solution containing acetic acid exhibited 1.5-fold higher relative conductivity (approximately 90%) as compared to those (approximately 60%) of both citric and malic acids, implying that exposure of garlic cloves to acetic acid not only changed the permeability of the plasma membrane but also increased the permeability of intracellular membrane. Exposure of garlic to acetic acid led to the production of precipitate along the tonoplast, but no precipitate was formed by citric and malic acids. This indicates that the structure of the tonoplast was damaged by this treatment. Further support for this conclusion comes from results showing that the concentration of thiosulfinates [which are produced only by catalytic conversion of S-alk(en)yl-l-cysteine sulfoxides in cytosol by alliinase located in the vacuole] in the acetic acid pickling solution is 1.3 mg/mL, but almost no thiosulfinates were detected in the pickling solution of citric and malic acids. Thus, all present results suggest that damage of

  16. Botulinum Toxin Complex Increases Paracellular Permeability in Intestinal Epithelial Cells via Activation of p38 Mitogen-Activated Protein Kinase (United States)

    MIYASHITA, Shin-ichiro; SAGANE, Yoshimasa; INUI, Ken; HAYASHI, Shintaro; MIYATA, Keita; SUZUKI, Tomonori; OHYAMA, Tohru; WATANABE, Toshihiro; NIWA, Koichi


    ABSTRACT Clostridium botulinum produces a large toxin complex (L-TC) that increases paracellular permeability in intestinal epithelial cells by a mechanism that remains unclear. Here, we show that mitogen-activated protein kinases (MAPKs) are involved in this permeability increase. Paracellular permeability was measured by FITC-dextran flux through a monolayer of rat intestinal epithelial IEC-6 cells, and MAPK activation was estimated from western blots. L-TC of C. botulinum serotype D strain 4947 increased paracellular dextran flux and activated extracellular signal-regulated kinase (ERK), p38, but not c-Jun N-terminal kinase (JNK) in IEC-6 cells. The permeability increase induced by L-TC was abrogated by the p38 inhibitor SB203580. These results indicate that L-TC increases paracellular permeability by activating p38, but not JNK and ERK. PMID:23884081

  17. Improvement of Carbon Dioxide Sweep Efficiency by Utilization of Microbial Permeability Profile Modification to Reduce the Amount of Oil Bypassed During Carbon Dioxide Flood

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Darrel [Mississippi State Univ., Mississippi State, MS (United States); Brown, Lewis [Mississippi State Univ., Mississippi State, MS (United States); Lynch, F. Leo [Mississippi State Univ., Mississippi State, MS (United States); Kirkland, Brenda L. [Mississippi State Univ., Mississippi State, MS (United States); Collins, Krystal M. [Mississippi State Univ., Mississippi State, MS (United States); Funderburk, William K. [Mississippi State Univ., Mississippi State, MS (United States)


    The objective of this project was to couple microbial permeability profile modification (MPPM), with carbon dioxide flooding to improve oil recovery from the Upper Cretaceous Little Creek Oil Field situated in Lincoln and Pike counties, MS. This study determined that MPPM technology, which improves production by utilizing environmentally friendly nutrient solutions to simulate the growth of the indigenous microflora in the most permeable zones of the reservoir thus diverting production to less permeable, previously unswept zones, increased oil production without interfering with the carbon dioxide flooding operation. Laboratory tests determined that no microorganisms were produced in formation waters, but were present in cores. Perhaps the single most significant contribution of this study is the demonstration that microorganisms are active at a formation temperature of 115°C (239°F) by using a specially designed culturing device. Laboratory tests were employed to simulate the MPPM process by demonstrating that microorganisms could be activated with the resulting production of oil in coreflood tests performed in the presence of carbon dioxide at 66°C (the highest temperature that could be employed in the coreflood facility). Geological assessment determined significant heterogeneity in the Eutaw Formation, and documented relatively thin, variably-lithified, well-laminated sandstone interbedded with heavily-bioturbated, clay-rich sandstone and shale. Live core samples of the Upper Cretaceous Eutaw Formation from the Heidelberg Field, MS were quantitatively assessed using SEM, and showed that during MPPM permeability modification occurs ubiquitously within pore and throat spaces of 10-20 μm diameter. Testing of the MPPM procedure in the Little Creek Field showed a significant increase in production occurred in two of the five production test wells; furthermore, the decline curve in each of the production wells became noticeably less steep. This project greatly

  18. VEGF increases the permeability of sheep pleura ex vivo through VEGFR2 stimulation. (United States)

    Peppa, Vasiliki I; Arsenopoulou, Zoi V; Zarogiannis, Sotirios G; Deligiorgi, Triantafyllia; Jagirdar, Rajesh; Makantasis, Ioannis; Stefanidis, Ioannis; Liakopoulos, Vassilios; Molyvdas, Paschalis-Adam; Gourgoulianis, Konstantinos I; Hatzoglou, Chrissi


    Vascular endothelial growth factor (VEGF), a cytokine that increases vascular permeability to water and proteins and induces angiogenesis, has been implicated in the development of pleural effusions. Inflammatory and malignant pleural effusions are rich in VEGF content while mesothelial cells produce and excrete VEGF. In this report we aimed at investigating by means of electrophysiology the direct effects of VEGF on the parietal and visceral sheep pleura as well as the type of receptors that mediate this effect. Our findings show that VEGF has a direct effect on the pleural mesothelium rendering it more permeable and this effect is mediated through the stimulation of VEGF receptor 2. Our findings shed more light to the role of VEGF in the pathogenesis of pleural effusions and provide functional evidence for a role of VEGFR2 on the pleural mesothelium that has never been studied before. Copyright © 2014 Elsevier Ltd. All rights reserved.

  19. C-reactive protein increases BBB permeability: implications for obesity and neuroinflammation. (United States)

    Hsuchou, Hung; Kastin, Abba J; Mishra, Pramod K; Pan, Weihong


    Acute phase C-reactive protein (CRP), elevated in obesity and inflammation, is a major binding protein for leptin. It is thought that CRP contributes to leptin resistance by preventing leptin from crossing the blood-brain barrier (BBB). Here we determined how CRP interacts with the BBB and whether it deters leptin from reaching CNS targets. BBB permeability, compartmental distribution, tracer stability, and expression of tight junction protein and inflammatory marker were determined. CRP was stable in blood, but did not permeate the BBB in trace amounts. However, it increased paracellular permeability at a higher dose. Agouti viable (A(vy)) mice with adult-onset obesity show higher CRP entry into the brain. CRP did not permeate hCMEC/D3 cells nor change zona occludin-1 or cyclooxygenase-2 expression. An intermediate dose of CRP had no effect on leptin transport across the BBB after co-treatment. Thus, acute interactions between CRP and leptin at the BBB level were negligible and did not explain the leptin resistance seen in obesity. The interactions of CRP and the BBB are a two-phase process, with increased paracellular permeability at a high dose that enables its entry into the CNS and serves to induce reactive gliosis and impair CNS function. Copyright © 2012 S. Karger AG, Basel.

  20. Plasma from preeclamptic women increases blood-brain barrier permeability: role of vascular endothelial growth factor signaling. (United States)

    Amburgey, Odül A; Chapman, Abbie C; May, Victor; Bernstein, Ira M; Cipolla, Marilyn J


    Circulating factors in preeclamptic women are thought to cause endothelial dysfunction and thereby contribute to the progression of this hypertensive condition. Despite the involvement of neurological complications in preeclampsia, there is a paucity of data regarding the effect of circulating factors on cerebrovascular function. Using a rat model of pregnancy, we investigated blood-brain barrier permeability, myogenic activity, and the influence of endothelial vasodilator mechanisms in cerebral vessels exposed intraluminally to plasma from normal pregnant or preeclamptic women. In addition, the role of vascular endothelial growth factor signaling in mediating changes in permeability in response to plasma was investigated. A 3-hour exposure to 20% normal pregnant or preeclamptic plasma increased blood-brain barrier permeability by ≈6.5- and 18.0-fold, respectively, compared with no plasma exposure (Pvascular endothelial growth factor receptor kinase activity prevented the increase in permeability in response to preeclamptic plasma but had no effect on changes in permeability of vessels exposed to normal pregnant plasma. Circulating factors in preeclamptic plasma did not affect myogenic activity or the influence of endothelium on vascular tone. These findings demonstrate that acute exposure to preeclamptic plasma has little effect on reactivity of cerebral arteries but significantly increases blood-brain barrier permeability. Prevention of increased permeability by inhibition of vascular endothelial growth factor signaling suggests that activation of this pathway may be responsible for increased blood-brain barrier permeability after exposure to preeclamptic plasma.

  1. Increased intestinal permeability in endotoxic pigs. Mesenteric hypoperfusion as an etiologic factor

    Energy Technology Data Exchange (ETDEWEB)

    Fink, M.P.; Antonsson, J.B.; Wang, H.L.; Rothschild, H.R. (Univ. of Massachusetts Medical Center, Worcester (USA))


    Infusing pigs with lipopolysaccharide (LPS) decreases superior mesenteric artery blood flow (Qsma), suggesting that mesenteric hypoperfusion may be responsible for LPS-induced alterations in gut mucosal permeability. To test this hypothesis, we studied four groups of anesthetized swine. Group 1 animals (N = 6) were infused with LPS (250 micrograms/kg over 1 hour beginning at 60 minutes) and continuously resuscitated with Ringer's lactate (48 mL/kg per hour). In group 2 (N = 5), Qsma was decreased by 50% by means of a mechanical occluder to mimic the LPS-induced alterations in Qsma observed in group I. Group 3 (N = 5) was included to document our ability to detect ischemia/reperfusion-induced alterations in mucosal permeability; in these pigs, Qsma was decreased in steps to zero flow (at 150 to 210 minutes) and then perfusion was restored (at 210 to 270 minutes). Pigs in group 4 (N = 6) served as normal controls; these animals were resuscitated with Ringer's lactate at the same rate as in group 1 but were not infused with LPS. To assess mucosal permeability, we measured plasma-to-lumen clearances for two markers, chromium 51-labeled edetic acid monohydrate (EDTA) and urea. Loading and maintenance infusions of the markers were given intravenously, and a 20-cm isolated segment of small intestine was continuously perfused at 2 mL/min with Ringer's lactate at 37 degrees C. Results were expressed as the ratio of the clearances for the two probes (CEDTA/CUREA). In group 3, CEDTA/CUREA was 999% +/- 355% of baseline at 270 minutes. In group 1, CEDTA/CUREA was 572% +/- 235% of baseline at 270 minutes. In groups 2 and 4, however, CEDTA/CUREA did not change significantly from the baseline value over the duration of the study. These data suggest that increased mucosal permeability after LPS is due to factors other than (or in addition to) mesenteric hypoperfusion.

  2. Roux-en-Y gastric bypass increases intravenous ethanol self-administration in dietary obese rats.

    Directory of Open Access Journals (Sweden)

    James E Polston

    Full Text Available Roux-en-Y gastric bypass surgery (RYGB is an effective treatment for severe obesity. Clinical studies however have reported susceptibility to increased alcohol use after RYGB, and preclinical studies have shown increased alcohol intake in obese rats after RYGB. This could reflect a direct enhancement of alcohol's rewarding effects in the brain or an indirect effect due to increased alcohol absorption after RGYB. To rule out the contribution that changes in alcohol absorption have on its rewarding effects, here we assessed the effects of RYGB on intravenously (IV administered ethanol (1%. For this purpose, high fat (60% kcal from fat diet-induced obese male Sprague Dawley rats were tested ~2 months after RYGB or sham surgery (SHAM using both fixed and progressive ratio schedules of reinforcement to evaluate if RGYB modified the reinforcing effects of IV ethanol. Compared to SHAM, RYGB rats made significantly more active spout responses to earn IV ethanol during the fixed ratio schedule, and achieved higher breakpoints during the progressive ratio schedule. Although additional studies are needed, our results provide preliminary evidence that RYGB increases the rewarding effects of alcohol independent of its effects on alcohol absorption.

  3. Increased Hepatic Insulin Clearance After Roux-en-Y Gastric Bypass

    DEFF Research Database (Denmark)

    Bojsen-Møller, Kirstine N; Dirksen, Carsten; Jørgensen, Nils B


    Context:Roux-en-Y gastric bypass (RYGB) improves glucose tolerance and ameliorates fasting hyperinsulinemia within days after surgery. Improvements in hepatic insulin sensitivity and insulin clearance could contribute importantly to these effects.Objective:The objective of the investigation...

  4. Increased neutrophil priming and sensitization before commencing cardiopulmonary bypass in cardiac surgical patients

    NARCIS (Netherlands)

    Gu, YJ; Schoen, P; Tigchelaar, [No Value; Loef, BG; Ebels, T; Rankin, AJ; van Oeveren, W


    Background. Neutrophil activation is implicated in postoperative complications in patients having cardiac surgery with cardiopulmonary bypass (CPB). This study was designed to determine the temporal fluctuations in the primability of neutrophils in the preoperative, intraoperative, and postoperative

  5. Aeroacoustic Analysis of Fan Noise Reduction With Increased Bypass Nozzle Area (United States)

    Woodward, Richard P.; Hughes, Christopher E.; Podboy, Gary G.


    An advanced model turbofan was tested in the NASA Glenn 9-by 15-Foot Low Speed Wind Tunnel (9x15 LSWT) to explore far field acoustic effects of increased bypass nozzle area. This fan stage test was part of the NASA Glenn Fan Broadband Source Diagnostic Test, second entry (SDT2) which acquired aeroacoustic results over a range of test conditions. The baseline nozzle was sized to produce maximum stage performance at cruise condition. However, the wind tunnel testing is conducted near sea level condition. Therefore, in order to simulate and obtain performance at other operating conditions, two additional nozzles were designed and tested one with +5 percent increase in weight flow (+5.4 percent increase in nozzle area compared with the baseline nozzle), sized to simulate the performance at the stage design point (takeoff) condition, and the other with a +7.5 percent increase in weight flow (+10.9 percent increase in nozzle area) sized for maximum weight flow with a fixed nozzle at sea level condition. Measured acoustic benefits with increased nozzle area were very encouraging, showing overall sound power level (OAPWL) reductions of 2 or more dB while the stage thrust actually increased by 2 to 3 percent except for the most open nozzle at takeoff rotor speed where stage performance decreased. Effective perceived noise levels for a 1500 ft engine flyover and 3.35 scale factor showed a similar noise reduction of 2 or more EPNdB. Noise reductions, principally in the level of broadband noise, were observed everywhere in the far field. Laser Doppler Velocimetry measurements taken downstream of the rotor showed that the total turbulent velocity decreased with increasing nozzle flow, which may explain the reduced rotor broadband noise levels.

  6. Roux-en-Y Gastric Bypass Surgery Increases Respiratory Quotient and Energy Expenditure during Food Intake. (United States)

    Werling, Malin; Fändriks, Lars; Olbers, Torsten; Bueter, Marco; Sjöström, Lars; Lönroth, Hans; Wallenius, Ville; Stenlöf, Kaj; le Roux, Carel W


    The mechanisms determining long-term weight maintenance after Roux-en-Y gastric bypass (RYGB) remain unclear. Cross sectional studies have suggested that enhanced energy expenditure (EE) may play a significant role and the aim of this study was to reveal the impact of RYGB on each major component constituting total EE. Six obese female subjects, without other co-morbidities, were assessed before and at 10 days, 3 and 20 months after RYGB. Indirect calorimetry in a metabolic chamber was used to assess 24 h EE at each study visit. Other measurements included body composition by DEXA, gut hormone profiles and physical activity (PA) using high sensitivity accelerometers. Median Body Mass Index decreased from 41.1 (range 39.1-44.8) at baseline to 28 kg/m2 (range 22.3-30.3) after 20 months (pPA over 24 h did not change after surgery whereas 24 h EE and basal metabolic rate (BMR) decreased. EE after a standard meal increased after surgery when adjusted for total tissue (pEE after food intake resulting in an increased contribution to total EE over 24 h when corrected for total tissue.

  7. Magnetic resonance imaging-guided focused ultrasound to increase localized blood-spinal cord barrier permeability. (United States)

    Payne, Allison H; Hawryluk, Gregory W; Anzai, Yoshimi; Odéen, Henrik; Ostlie, Megan A; Reichert, Ethan C; Stump, Amanda J; Minoshima, Satoshi; Cross, Donna J


    Spinal cord injury (SCI) affects thousands of people every year in the USA, and most patients are left with some permanent paralysis. Therapeutic options are limited and only modestly affect outcome. To address this issue, we used magnetic resonance imaging-guided focused ultrasound (MRgFUS) as a non-invasive approach to increase permeability in the blood-spinal cord barrier (BSCB). We hypothesize that localized, controlled sonoporation of the BSCB by MRgFUS will aid delivery of therapeutics to the injury. Here, we report our preliminary findings for the ability of MRgFUS to increase BSCB permeability in the thoracic spinal cord of a normal rat model. First, an excised portion of normal rat spinal column was used to characterize the acoustic field and to estimate the insertion losses that could be expected in an MRgFUS blood spinal cord barrier opening. Then, in normal rats, MRgFUS was applied in combination with intravenously administered microbubbles to the spinal cord region. Permeability of the BSCB was indicated as signal enhancement by contrast administered prior to T1-weighted magnetic resonance imaging and verified by Evans blue dye. Neurological testing using the Basso, Beattie, and Breshnahan scale and the ladder walk was normal in 8 of 10 rats tested. Two rats showed minor impairment indicating need for further refinement of parameters. No gross tissue damage was evident by histology. In this study, we have opened successfully the blood spinal cord barrier in the thoracic region of the normal rat spine using magnetic resonance-guided focused ultrasound combined with microbubbles.

  8. Inhaled nitric oxide prevents the increase in pulmonary vascular permeability caused by hydrogen peroxide. (United States)

    Poss, W B; Timmons, O D; Farrukh, I S; Hoidal, J R; Michael, J R


    Given the interest in using inhaled nitric oxide (NO.) to treat acute lung injury and the importance of oxygen radicals in its pathogenesis, we studied the effects, in buffer-perfused isolated rabbit lungs, of inhaled NO. (24 ppm) on the injury caused by generating hydrogen peroxide with glucose and glucose oxidase (GOX). Experiments were performed at a constant pulmonary arterial pressure. GOX substantially augmented vascular permeability, as demonstrated by an increase in the lung-to-perfusate 125I-labeled albumin ratio, lavage-to-perfusate 125I-albumin ratio, wet-to-dry lung weight ratio, and pulmonary vascular filtration coefficient. Lungs treated with inhaled NO. before perfusion with GOX had lung-to-perfusate and lavage-to-perfusate 125I-albumin ratios that were not significantly different from control values and intermediate between the control and GOX groups. Inhaled NO. also prevented the increase in wet-to-dry lung weight ratio and pulmonary vascular filtration coefficient caused by GOX.. Thus inhaled NO. substantially reduced in the isolated lung the increase in pulmonary vascular permeability produced by the intravascular generation of hydrogen peroxide.

  9. Ascorbic Acid may Exacerbate Aspirin-Induced Increase in Intestinal Permeability. (United States)

    Sequeira, Ivana R; Kruger, Marlena C; Hurst, Roger D; Lentle, Roger G


    Ascorbic acid in combination with aspirin has been used to prevent aspirin-induced oxidative GI damage. We aimed to determine whether ascorbic acid reduces or prevents aspirin-induced changes in intestinal permeability over a 6-hr period using saccharidic probes mannitol and lactulose. The effects of administration of 600 mg aspirin alone, 500 mg ascorbic acid alone and simultaneous dosage of both agents were compared in a cross-over study in 28 healthy female volunteers. These effects were also compared with that of a placebo. The ability of ascorbic acid to mitigate the effects of aspirin when administered either half an hour before or after dosage with aspirin was also assessed in 19 healthy female volunteers. The excretion of lactulose over the 6-hr period was augmented after consumption of either aspirin or ascorbic acid compared with that after consumption of placebo. Dosage with ascorbic acid alone augmented the excretion of lactulose more than did aspirin alone. Simultaneous dosage with both agents augmented the excretion of lactulose in an additive manner. The timing of dosage with ascorbic acid in relation to that with aspirin had no significant effect on the excretion of the two sugars. These findings indicate that ascorbic acid does not prevent aspirin-induced increase in gut permeability rather that both agents augment it to a similar extent. The additive effect on simultaneous dosage with both agents in augmenting the absorption of lactulose suggests that each influences paracellular permeability by different pathways. © 2015 Nordic Association for the Publication of BCPT (former Nordic Pharmacological Society).

  10. Mitochondrial permeability transition pore (MPTP) desensitization increases sea urchin spermatozoa fertilization rate. (United States)

    Torrezan-Nitao, Elis; Boni, Raianna; Marques-Santos, Luis Fernando


    Mitochondrial permeability transition pore (MPTP) is a protein complex whose opening promotes an abrupt increase in mitochondrial inner membrane permeability. Calcium signaling pathways are described in gametes and are involved in the fertilization process. Although mitochondria may act as Ca(2+) store and have a fast calcium-releasing mechanism through MPTP, its contribution to fertilization remains unclear. The work aimed to investigate the MPTP phenomenon in sea urchin spermatozoa and its role on the fertilization. Several pharmacological tools were used to evaluate the MPTP's physiology. Our results demonstrated that MPTP occurs in male gametes in a Ca(2+) - and voltage-dependent manner and it is sensitive to cyclosporine A. Additionally, our data show that MPTP opening does not alter ROS generation in sperm cells. Inhibition of MPTP in spermatozoa strongly improved the fertilization rate, which may involve mechanisms that increase the spermatozoa lifespan. The present work is the first report of the presence of a voltage- and Ca(2+) -dependent MPTP in gametes of invertebrates and indicates MPTP opening as another evolutionary feature shared by sea urchins and mammals. Studies about MPTP in sea urchin male gametes may contribute to the elucidation of several mechanisms involved in sperm infertility. © 2016 International Federation for Cell Biology.

  11. The increase in permeability of postcapillary venules in lymph nodes subjected to the regional graft-versus-host reaction. (United States)

    Kotani, M; Matsuno, K; Ezaki, T; Ueda, M


    The changes in permeability of blood vessels in the draining lymph nodes of the footpads undergoing a regional graft-versus-host, host-versus-graft, or antisheep erythrocytes reaction were examined 30 minutes after intravenous injection of Pelikan Ink. Massive leakage of carbon particles was seen only in the postcapillary venules where endothelial cells became flattened. This was observed in lymph nodes 3 to 7 days after induction of the regional graft-versus-host reaction and occurred mainly through intercellular gaps in the endothelium. This transient increase in permeability of postcapillary venules was apparently independent of cellular emigration. No obvious increase in carbon permeability was observed in lymph nodes subjected to the regional host-versus-graft reaction, whereas the uptake of cellular and noncellular elements of the blood by endothelial cells of postcapillary venules was greatly increased. There was no increase in carbon permeability in antisheep erythrocyte-stimulated lymph nodes.

  12. Acute hyperglycemia and hyperinsulinemia enhance vasodilatation in type 1 diabetes mellitus without increasing capillary permeability and inducing endothelial dysfunction

    NARCIS (Netherlands)

    Kant, GD; Dullaart, RPF; Smit, AJ

    Uncomplicated Type I (insulin-dependent) diabetes mellitus is characterized by generalized vasodilatation. Its possible correlates, increased microvascular permeability and endothelial dysfunction, have been associated with long-term complications. The objective was to study the effects of acute

  13. Roux-en-Y Gastric Bypass Surgery Increases Respiratory Quotient and Energy Expenditure during Food Intake.

    Directory of Open Access Journals (Sweden)

    Malin Werling

    Full Text Available The mechanisms determining long-term weight maintenance after Roux-en-Y gastric bypass (RYGB remain unclear. Cross sectional studies have suggested that enhanced energy expenditure (EE may play a significant role and the aim of this study was to reveal the impact of RYGB on each major component constituting total EE.Six obese female subjects, without other co-morbidities, were assessed before and at 10 days, 3 and 20 months after RYGB. Indirect calorimetry in a metabolic chamber was used to assess 24 h EE at each study visit. Other measurements included body composition by DEXA, gut hormone profiles and physical activity (PA using high sensitivity accelerometers.Median Body Mass Index decreased from 41.1 (range 39.1-44.8 at baseline to 28 kg/m2 (range 22.3-30.3 after 20 months (p<0.05. Lean tissue decreased from 55.9 (range 47.5-59.3 to 49.5 (range 41.1-54.9 kg and adipose tissue from 61 (range 56-64.6 to 27 (range 12-34.3 kg (both p<0.05. PA over 24 h did not change after surgery whereas 24 h EE and basal metabolic rate (BMR decreased. EE after a standard meal increased after surgery when adjusted for total tissue (p<0.05. After an initial drop, RQ (respiratory quotient had increased at 20 months, both as measured during 24 h and after food intake (p<0.05.RYGB surgery up-regulates RQ and EE after food intake resulting in an increased contribution to total EE over 24 h when corrected for total tissue.

  14. Acarbose improves hypoglycaemia following gastric bypass surgery without increasing glucagon-like peptide 1 levels. (United States)

    Valderas, Juan Patricio; Ahuad, Jessica; Rubio, Lorena; Escalona, Manuel; Pollak, Felipe; Maiz, Alberto


    Postprandial hypoglycaemia is a severe complication of Roux-en-Y gastric bypass (RYGBP). Acarbose, an α-glucosidase inhibitor (AGI), is employed in its treatment. Several studies have shown that AGIs increase the postprandial levels of glucagon-like peptide 1 (GLP-1). However, an excessive level of GLP-1 is one of the factors involved in the physiopathology of this condition. We analysed the effect of acarbose oral administration in eight RYBGP patients with clinically significant hypoglycaemia or dumping syndrome. Glucose, insulin and GLP-1 plasma levels in fasting and after ingestion of a standard meal (Ensure Plus®; 13 g protein, 50 g carbohydrate, 11 g fat) were measured. The test was repeated the following week with the oral administration of 100 mg of acarbose 15 min prior to the meal. Five patients developed asymptomatic hypoglycaemia during the test (glucose level <50 mg/dl) with inappropriately high insulin levels and exaggerated GLP-1 response. Acarbose ingestion avoided hypoglycaemia in all of the patients and increased the lowest plasma glucose level (46.4 ± 4.8 vs. 59.0 ± 2.6 mg/dl, p < 0.01). Acarbose ingestion decreased the area under the curve for serum insulin and GLP-1 levels at 15 min after the meal. Acarbose avoided postprandial hypoglycaemia following RYGBP by decreasing the hyperinsulinemic response. This was associated with a decrease in early GLP-1 secretion, in contrast to that observed in non-surgical subjects. This finding could be explained by the reduction of glucose load in the jejunum produced by the α-glucosidase inhibition, which is the main stimulus for GLP-1 secretion.

  15. Link Between Increased Satiety Gut Hormones and Reduced Food Reward After Gastric Bypass Surgery for Obesity. (United States)

    Goldstone, Anthony P; Miras, Alexander D; Scholtz, Samantha; Jackson, Sabrina; Neff, Karl J; Pénicaud, Luc; Geoghegan, Justin; Chhina, Navpreet; Durighel, Giuliana; Bell, Jimmy D; Meillon, Sophie; le Roux, Carel W


    Roux-en-Y gastric bypass (RYGB) surgery is an effective long-term intervention for weight loss maintenance, reducing appetite, and also food reward, via unclear mechanisms. To investigate the role of elevated satiety gut hormones after RYGB, we examined food hedonic-reward responses after their acute post-prandial suppression. These were randomized, placebo-controlled, double-blind, crossover experimental medicine studies. Two groups, more than 5 months after RYGB for obesity (n = 7-11), compared with nonobese controls (n = 10), or patients after gastric banding (BAND) surgery (n = 9) participated in the studies. Studies were performed after acute administration of the somatostatin analog octreotide or saline. In one study, patients after RYGB, and nonobese controls, performed a behavioral progressive ratio task for chocolate sweets. In another study, patients after RYGB, and controls after BAND surgery, performed a functional magnetic resonance imaging food picture evaluation task. Octreotide increased both appetitive food reward (breakpoint) in the progressive ratio task (n = 9), and food appeal (n = 9) and reward system blood oxygen level-dependent signal (n = 7) in the functional magnetic resonance imaging task, in the RYGB group, but not in the control groups. Octreotide suppressed postprandial plasma peptide YY, glucagon-like peptide-1, and fibroblast growth factor-19 after RYGB. The reduction in plasma peptide YY with octreotide positively correlated with the increase in brain reward system blood oxygen level-dependent signal in RYGB/BAND subjects, with a similar trend for glucagon-like peptide-1. Enhanced satiety gut hormone responses after RYGB may be a causative mechanism by which anatomical alterations of the gut in obesity surgery modify behavioral and brain reward responses to food.

  16. Increased post-operative cardiopulmonary fitness in gastric bypass patients is explained by weight loss

    DEFF Research Database (Denmark)

    Lund, M. T.; Hansen, M.; Wimmelmann, C. L.


    Roux-en-Y gastric bypass (RYGB) leads to a major weight loss in obese patients. However, given that most patients remain obese after the weight loss, regular exercise should be part of a healthier lifestyle. The primary aim of this study was to investigate the cardiopulmonary fitness in obese pat...

  17. Increased concentrations of L-lactate in the rectal lumen in patients undergoing cardiopulmonary bypass

    DEFF Research Database (Denmark)

    Perner, A; Jørgensen, V L; Poulsen, T D


    Gut ischaemia may contribute to morbidity in patients after cardiopulmonary bypass (CPB), but little is known about the metabolic state of the large bowel in such patients. Therefore we estimated the concentrations of L-lactate and Pco(2) in rectal mucosa in patients undergoing cardiac surgery...

  18. Low extracellular Ca2+ conditions induce an increase in brain endothelial permeability that involves intercellular Ca2+ waves. (United States)

    De Bock, Marijke; Culot, Maxime; Wang, Nan; da Costa, Anaelle; Decrock, Elke; Bol, Mélissa; Bultynck, Geert; Cecchelli, Romeo; Leybaert, Luc


    The intracellular calcium concentration ([Ca(2+)](i)) is an important factor determining the permeability of endothelial barriers including the blood-brain barrier (BBB). However, nothing is known concerning the effect of spatially propagated intercellular Ca(2+) waves (ICWs). The propagation of ICWs relies in large part on channels formed by connexins that are present in endothelia. We hypothesized that ICWs may result in a strong disturbance of endothelial function, because the [Ca(2+)](i) changes are coordinated and involve multiple cells. Thus, we aimed to investigate the effect of ICWs on endothelial permeability. ICW activity was triggered in immortalized and primary brain endothelial cells by lowering the extracellular Ca(2+) concentration. Low extracellular Ca(2+) increased the endothelial permeability and this was significantly suppressed by buffering [Ca(2+)](i) with BAPTA-AM, indicating a central role of [Ca(2+)](i) changes. The endothelial permeability increase was furthermore inhibited by the connexin channel blocking peptide Gap27, which also blocked the ICWs, and by inhibiting protein kinase C (PKC), Ca(2+)/calmodulin-dependent kinase II (CaMKII) and actomyosin contraction. We compared these observations with the [Ca(2+)](i) changes and permeability alterations provoked by the inflammatory agent bradykinin (BK), which triggers oscillatory [Ca(2+)](i) changes without wave activity. BK-associated [Ca(2+)](i) changes and the endothelial permeability increase were significantly smaller than those associated with ICWs, and the permeability increase was not influenced by inhibition of PKC, CaMKII or actomyosin contraction. We conclude that ICWs significantly increase endothelial permeability and therefore, the connexins that underlie wave propagation form an interesting target to limit BBB alterations. This article is part of a Special Issue entitled Electrical Synapses. Copyright © 2012 Elsevier B.V. All rights reserved.

  19. Oral Delivery of Lipophilic Drugs: The Tradeoff between Solubility Increase and Permeability Decrease When Using Cyclodextrin-Based Formulations (United States)

    Beig, Avital; Agbaria, Riad; Dahan, Arik


    The purpose of this study was to investigate the impact of oral cyclodextrin-based formulation on both the apparent solubility and intestinal permeability of lipophilic drugs. The apparent solubility of the lipophilic drug dexamethasone was measured in the presence of various HPβCD levels. The drug’s permeability was measured in the absence vs. presence of HPβCD in the rat intestinal perfusion model, and across Caco-2 cell monolayers. The role of the unstirred water layer (UWL) in dexamethasone’s absorption was studied, and a simplified mass-transport analysis was developed to describe the solubility-permeability interplay. The PAMPA permeability of dexamethasone was measured in the presence of various HPβCD levels, and the correlation with the theoretical predictions was evaluated. While the solubility of dexamethasone was greatly enhanced by the presence of HPβCD (K1∶1 = 2311 M−1), all experimental models showed that the drug’s permeability was significantly reduced following the cyclodextrin complexation. The UWL was found to have no impact on the absorption of dexamethasone. A mass transport analysis was employed to describe the solubility-permeability interplay. The model enabled excellent quantitative prediction of dexamethasone’s permeability as a function of the HPβCD level. This work demonstrates that when using cyclodextrins in solubility-enabling formulations, a tradeoff exists between solubility increase and permeability decrease that must not be overlooked. This tradeoff was found to be independent of the unstirred water layer. The transport model presented here can aid in striking the appropriate solubility-permeability balance in order to achieve optimal overall absorption. PMID:23874557

  20. Transcranial direct current stimulation transiently increases the blood-brain barrier solute permeability in vivo (United States)

    Shin, Da Wi; Khadka, Niranjan; Fan, Jie; Bikson, Marom; Fu, Bingmei M.


    Transcranial Direct Current Stimulation (tDCS) is a non-invasive electrical stimulation technique investigated for a broad range of medical and performance indications. Whereas prior studies have focused exclusively on direct neuron polarization, our hypothesis is that tDCS directly modulates endothelial cells leading to transient changes in blood-brain-barrier (BBB) permeability (P) that are highly meaningful for neuronal activity. For this, we developed state-of-the-art imaging and animal models to quantify P to various sized solutes after tDCS treatment. tDCS was administered using a constant current stimulator to deliver a 1mA current to the right frontal cortex of rat (approximately 2 mm posterior to bregma and 2 mm right to sagittal suture) to obtain similar physiological outcome as that in the human tDCS application studies. Sodium fluorescein (MW=376), or FITC-dextrans (20K and 70K), in 1% BSA mammalian Ringer was injected into the rat (SD, 250-300g) cerebral circulation via the ipsilateral carotid artery by a syringe pump at a constant rate of ~3 ml/min. To determine P, multiphoton microscopy with 800-850 nm wavelength laser was applied to take the images from the region of interest (ROI) with proper microvessels, which are 100-200 micron below the pia mater. It shows that the relative increase in P is about 8-fold for small solute, sodium fluorescein, ~35-fold for both intermediate sized (Dex-20k) and large (Dex-70k) solutes, 10 min after 20 min tDCS pretreatment. All of the increased permeability returns to the control after 20 min post treatment. The results confirmed our hypothesis.

  1. Δ9-Tetrahydrocannabinol reverses TNFα-induced increase in airway epithelial cell permeability through CB2 receptors. (United States)

    Shang, Valerie C M; Kendall, David A; Roberts, Richard E


    Despite pharmacological treatment, bronchial hyperresponsiveness continues to deteriorate as airway remodelling persists in airway inflammation. Previous studies have demonstrated that the phytocannabinoid Δ9-tetrahydrocannabinol (THC) reverses bronchoconstriction with an anti-inflammatory action. The aim of this study was to investigate the effects of THC on bronchial epithelial cell permeability after exposure to the pro-inflammatory cytokine, TNFα. Calu-3 bronchial epithelial cells were cultured at air-liquid interface. Changes in epithelial permeability were measured using Transepithelial Electrical Resistance (TEER), then confirmed with a paracellular permeability assay and expression of tight junction proteins by Western blotting. Treatment with THC prevented the TNFα-induced decrease in TEER and increase in paracellular permeability. Cannabinoid CB1 and CB2 receptor-like immunoreactivity was found in Calu-3 cells. Subsequent experiments revealed that pharmacological blockade of CB2, but not CB1 receptor inhibited the THC effect. Selective stimulation of CB2 receptors displayed a similar effect to that of THC. TNFα decreased expression of the tight junction proteins occludin and ZO-1, which was prevented by pre-incubation with THC. These data indicate that THC prevents cytokine-induced increase in airway epithelial permeability through CB2 receptor activation. This highlights that THC, or other cannabinoid receptor ligands, could be beneficial in the prevention of inflammation-induced changes in airway epithelial cell permeability, an important feature of airways diseases. Copyright © 2016 Elsevier Inc. All rights reserved.

  2. Intestinal permeability is increased in children with non-alcoholic fatty liver disease, and correlates with liver disease severity. (United States)

    Giorgio, Valentina; Miele, Luca; Principessa, Luigi; Ferretti, Francesca; Villa, Maria Pia; Negro, Valentina; Grieco, Antonio; Alisi, Anna; Nobili, Valerio


    Increased intestinal permeability seems to play a major role in non-alcoholic liver disease development and progression. To investigate the prevalence of altered intestinal permeability in children with non-alcoholic fatty liver disease, and to study its potential association with the stage of liver disease. We performed a case-control study examining intestinal permeability in children using the lactulose-mannitol bowel permeability test. Overall, 39 consecutive patients (30 males, median age 12 years) and 21 controls (14 males, median age 11.8 years) were included. The lactulose/mannitol ratio resulted impaired in 12/39 patients (31%) and none of the controls. Intestinal permeability was higher in children with non-alcoholic fatty liver disease (lactulose/mannitol ratios: 0.038±0.037 vs. 0.008±0.007, pnon-alcoholic fatty liver disease group, intestinal permeability was increased in children with steatohepatitis compared to those with steatosis only (0.05±0.04 vs. 0.03 vs. 0.03, psteatohepatitis (2.27±0.68 vs. 2.80±0.35, pnon-alcoholic fatty liver disease, and correlates with the severity of the disease. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  3. An effective way to increase the high-frequency permeability of Fe3O4 nanorods (United States)

    Ren, Xiao; Yang, Haitao; Tang, Jin; Li, Zi-An; Su, Yi Kun; Geng, Sai; Zhou, Jun; Zhang, Xiangqun; Cheng, Zhaohua


    Uniform Fe3O4 magnetic nanorods (NRs) were successfully synthesized and oriented in epoxy resin under a rotating magnetic field. Magnetic induction fields within and around a single Fe3O4 nanorod in the remanence state were obtained by off-axis electron holography. The induction fields indicated a single domain state of the highly anisotropic Fe3O4 nanorod due to its strong magnetic shape anisotropy. Quantitative magnetic moment analysis of the obtained phase image yielded an average magnetization of 0.53 T of a single Fe3O4 nanorod. Moreover, the real part of the permeability (μ') of magnetic-oriented Fe3O4 NRs is obviously higher than that of random Fe3O4 NRs in the GHz range. The oriented Fe3O4 NRs exhibit a higher resonance peak at 4.75 GHz compared to the bulk counterpart (1.2 GHz) in the frequency dependence of μ in the range of 1-10 GHz. Moreover, the calculated μ value of the oriented Fe3O4 NRs could be improved to 4.22 with the increased dipolar interaction strength using the OOMMF software. These results could play a guiding significance in the development of an effective method to improve the permeability of magnetic nanomaterials at GHz working frequency.Uniform Fe3O4 magnetic nanorods (NRs) were successfully synthesized and oriented in epoxy resin under a rotating magnetic field. Magnetic induction fields within and around a single Fe3O4 nanorod in the remanence state were obtained by off-axis electron holography. The induction fields indicated a single domain state of the highly anisotropic Fe3O4 nanorod due to its strong magnetic shape anisotropy. Quantitative magnetic moment analysis of the obtained phase image yielded an average magnetization of 0.53 T of a single Fe3O4 nanorod. Moreover, the real part of the permeability (μ') of magnetic-oriented Fe3O4 NRs is obviously higher than that of random Fe3O4 NRs in the GHz range. The oriented Fe3O4 NRs exhibit a higher resonance peak at 4.75 GHz compared to the bulk counterpart (1.2 GHz) in the

  4. Isoproterenol attenuates high vascular pressure-induced permeability increases in isolated rat lungs. (United States)

    Parker, J C; Ivey, C L


    To separate the contributions of cellular and basement membrane components of the alveolar capillary barrier to the increased microvascular permeability induced by high pulmonary venous pressures (Ppv), we subjected isolated rat lungs to increases in Ppv, which increased capillary filtration coefficient (Kfc) without significant hemorrhage (31 cmH2O) and with obvious extravasation of red blood cells (43 cmH2O). Isoproterenol (20 microM) was infused in one group (Iso) to identify a reversible cellular component of injury, and residual blood volumes were measured to assess extravasation of red blood cells through ruptured basement membranes. In untreated lungs (High Ppv group), Kfc increased 6.2 +/- 1.3 and 38.3 +/- 15.2 times baseline during the 31 and 43 cmH2O Ppv states. In Iso lungs, Kfc was 36.2% (P Kfc increases at moderate Ppv, possibly because of an endothelial effect, but it did not affect red cell extravasation at higher vascular pressures.

  5. Increasing plasmid transformation efficiency of natural spizizen method in Bacillus Subtilis by a cell permeable peptide

    Directory of Open Access Journals (Sweden)

    Mehrdad Moosazadeh Moghaddam


    Full Text Available Introduction: Some of bacterial species are able to uptake DNA molecule from environment, the yield of this process depends on some conditions such as plasmid size and host type. In the case of Bacillus subtilis, DNA uptake has low efficacy. Using Spizizen minimal medium is common method in plasmid transformation into B. subtilis, but rate of this process is not suitable and noteworthy. The aim of this study was investigation of novel method for improvement of DNA transformation into B. subtilis based on CM11 cationic peptide as a membrane permeable agent.Materials and methods: In this study, for optimization of pWB980 plasmid transformation into B. subtilis, the CM11 cationic peptide was used. For this purpose, B. subtilis competent cell preparation in the present of different concentration of peptide was implemented by two methods. In the first method, after treatment of bacteria with different amount of peptide for 14h, plasmid was added. In the second method, several concentration of peptide with plasmid was exposed to bacteria simultaneously. Bacteria that uptake DNA were screened on LB agar medium containing kanamycin. The total transformed bacteria per microgram of DNA was calculated and compared with the control.Results: Plasmid transformation in best conditions was 6.5 folds higher than the control. This result was statistically significant (P value <0.001.Discussion and conclusion: This study showed that CM11 cationic peptide as a membrane permeable agent was able to increase plasmid transformation rate into B. subtilis. This property was useful for resolution of low transformation efficacy.

  6. Increased gut permeability and bacterial translocation after chronic chlorpyrifos exposure in rats.

    Directory of Open Access Journals (Sweden)

    Claire Joly Condette

    Full Text Available The epithelium's barrier function is crucial for maintaining homeostasis and preventing the passage of food antigens and luminal bacteria. This function is essentially subserved by tight junctions (TJs, multiprotein complexes located in the most apical part of the lateral membrane. Some gastrointestinal disease states are associated with elevated intestinal permeability to macromolecules. In a study on rats, we determined the influence of chronic, daily ingestion of chlorpyrifos (CPF, a pesticide that crosses the placental barrier during pre- and postnatal periods on intestinal permeability and TJ characteristics in the pups. Fluorescein isothiocyanate (FITC-dextran was used as a marker of paracellular transport and mucosal barrier dysfunction. Pups were gavaged with FITC-dextran solution and blood samples were collected every 30 min for 400 min and analyzed spectrofluorimetrically. At sacrifice, different intestinal segments were resected and prepared for analysis of the transcripts (qPCR and localization (using immunofluorescence of ZO-1, occludin and claudins (scaffolding proteins that have a role in the constitution of TJs. In rats that had been exposed to CPF in utero and after birth, we observed a progressive increase in FITC-dextran passage across the epithelial barrier from 210 to 325 min at day 21 after birth (weaning but not at day 60 (adulthood. At both ages, there were significant changes in intestinal TJ gene expression, with downregulation of ZO-1 and occludin and upregulation of claudins 1 and 4. In some intestinal segments, there were changes in the cellular localization of ZO-1 and claudin 4 immunostaining. Lastly, bacterial translocation to the spleen was also observed. The presence of CPF residues in food may disturb epithelial homeostasis in rats. Changes in TJ protein expression and localization may be involved in gut barrier dysfunction in this model. Uncontrolled passage of macromolecules and bacteria across the intestinal

  7. Possible mechanisms for the inhibitory effect of Ruscus extract on increased microvascular permeability induced by histamine in hamster cheek pouch. (United States)

    Bouskela, E; Cyrino, F Z; Marcelon, G


    Extract of Ruscus aculeatus is used in treatment of venous insufficiency. In the present study, we used the hamster cheek pouch preparation and investigated in vivo the effects of an alpha 1 and alpha 2 adrenoceptor antagonists, a calcium blocker, Ruscus extract, and their combination on increased microvascular permeability induced by histamine. Experiments were performed on male hamsters; 30 min after completion of the cheek pouch preparation, fluorescein-labeled dextran (molecular weight 150,000) was given intravenously (i.v.). Histamine, applied topically, increased the number of fluorescent vascular leakage sites from postcapillary venules, evidence of an increase in macromolecular permeability, which was quantified by ultraviolet light microscopy as the number of leaky sites in the prepared area. Prazosin (alpha 1-adrenoceptor antagonist), diltiazem (calcium blocker), and Ruscus extract applied topically dose-dependently inhibited the macromolecular permeability-increasing effect of histamine. Rauwolscine (alpha 2-adrenoceptor antagonist), also applied topically, had no effect on histamine-induced permeability increase. Inhibition of the histamine-induced permeability increase evoked by Ruscus extract could be blocked by prazosin and by diltiazem but not by rauwolscine. These results indicate that any variation in the transmembrane flux of calcium impairs formation of microvascular leaky sites by histamine. Our results show that Ruscus extract has a protective effect against the leakage of FITC-dextran in hamster cheek pouch after administration of histamine that is modulated by calcium and selectively by alpha 1-adrenoceptors.

  8. Mitochondrial permeability transition increases reactive oxygen species production and induces DNA fragmentation in human spermatozoa. (United States)

    Treulen, Favián; Uribe, Pamela; Boguen, Rodrigo; Villegas, Juana V


    Does mitochondrial permeability transition (MPT) induced by calcium overload cause reactive oxygen species (ROS) production and DNA fragmentation in human spermatozoa? Studies conducted in vitro suggest that in human spermatozoa, MPT occurs in response to intracellular calcium increase and is associated with mitochondrial membrane potential (ΔΨm) dissipation, increased ROS production and DNA fragmentation. Oxidative stress is a major cause of defective sperm function in male infertility. By opening calcium-dependent pores in the inner mitochondrial membrane (IMM), MPT causes, among other things, increased ROS production and ΔΨm dissipation in somatic cells. MPT as a mechanism for generating oxidative stress and DNA fragmentation in human spermatozoa has not been studied. Human sperm were exposed to ionomycin for 1.5 h (n = 8) followed by analysis of sperm IMM permeability, ΔΨm, ROS production and DNA fragmentation. To evaluate the MPT in sperm cells, the calcein-AM and cobalt chloride method was used. The ΔΨm was evaluated by JC-1 staining, intracellular ROS production was evaluated with dihydroethidium and DNA fragmentation was evaluated by a modified TUNEL assay. Measurements were performed by fluorescence microscopy, confocal laser microscopy and flow cytometry. Decreased calcein fluorescence after treatment with ionomycin (P fragmentation. ROS production occurred prior to the decrease in ΔΨm. The study was carried out in vitro using motile sperm from healthy donors; tests on sperm from infertile patients were not carried out. We propose that the MPT, due to pores opening in sperm IMM, is an important mechanism of increased ROS and DNA fragmentation. Therefore, agents that modulate the opening of these pores might contribute to the prevention of damage by oxidative stress in human spermatozoa. This study was funded by grant DI12-0102 from the Universidad de La Frontera (J.V.V.) and a doctoral scholarship from CONICYT Chile (F.T.). The authors disclose

  9. Inhibition of endotoxin effects on cultured human middle ear epithelium by bactericidal permeability-increasing protein. (United States)

    Nell, M J; Albers-Op 't Hof, B M; Koerten, H K; Grote, J J


    Endotoxin can induce morphologic changes to middle ear epithelium, which can disturb the mucociliary clearance system (MCS) and lead to otitis media with effusion (OME). The bactericidal/permeability-increasing (BPI) protein is a major component of neutrophil granules and binds with high affinity to endotoxin. In this study, the capacity to inhibit the effects of endotoxin by rBPI21, a recombinant amino-terminal analog derived from BPI, was investigated on cultured human middle ear epithelium using light microscopy and scanning- and transmission electron microscopy. Human middle ear epithelium was air-exposed cultured on a collagenous underlayer with different additions of endotoxin and rBPI21 to the culture medium. The tissue specimens were inspected after 4 weeks for the number of ciliated and secretory cells, thickness of the mucosal layer, and cell size. The morphologic changes induced by endotoxin were increased thickness of the mucosal layer and increased number of secretory cells. These changes were significantly diminished or even absent when endotoxin was added with rBPI21 to the culture medium. rBPI21 can inhibit morphologic changes in the middle ear epithelium due to endotoxin. Hence, the authors believe that rBPI21 can be a new therapeutic agent in the treatment of OME.

  10. Acute high-intensity interval running increases markers of gastrointestinal damage and permeability but not gastrointestinal symptoms. (United States)

    Pugh, Jamie N; Impey, Samuel G; Doran, Dominic A; Fleming, Simon C; Morton, James P; Close, Graeme L


    The purpose of this study was to investigate the effects of high-intensity interval running on markers of gastrointestinal (GI) damage and permeability alongside subjective symptoms of GI discomfort. Eleven male runners completed an acute bout of high-intensity interval training (HIIT) (eighteen 400-m runs at 120% maximal oxygen uptake) where markers of GI permeability, intestinal damage, and GI discomfort symptoms were assessed and compared with resting conditions. Compared with rest, HIIT significantly increased serum lactulose/rhamnose ratio (0.051 ± 0.016 vs. 0.031 ± 0.021, p = 0.0047; 95% confidence interval (CI) = 0.006 to 0.036) and sucrose concentrations (0.388 ± 0.217 vs. 0.137 ± 0.148 mg·L -1 ; p HIIT and resting conditions. Plasma intestinal-fatty acid binding protein (I-FABP) was significantly increased (p HIIT whereas no changes were observed during rest. Mild symptoms of GI discomfort were reported immediately and at 24 h post-HIIT, although these symptoms did not correlate to GI permeability or I-FABP. In conclusion, acute HIIT increased GI permeability and intestinal I-FABP release, although these do not correlate with symptoms of GI discomfort. Furthermore, by using serum sampling, we provide data showing that it is possible to detect changes in intestinal permeability that is not observed using urinary sampling over a shorter time-period.

  11. Epithelial Cell Damage Activates Bactericidal/Permeability Increasing-Protein (BPI Expression in Intestinal Epithelium

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    Arjun Balakrishnan


    Full Text Available As the first line of defense against invading pathogen, intestinal epithelium produces various antimicrobial proteins (AMP that help in clearance of pathogen. Bactericidal/permeability-increasing protein (BPI is a 55 kDa AMP that is expressed in intestinal epithelium. Dysregulation of BPI in intestinal epithelium is associated with various inflammatory diseases like Crohn’s Disease, Ulcerative colitis, and Infectious enteritis’s. In this paper, we report a direct correlation between intestinal damage and BPI expression. In Caco-2 cells, we see a significant increase in BPI levels upon membrane damage mediated by S. aureus infection and pore-forming toxins (Streptolysin and Listeriolysin. Cells detect changes in potassium level as a Danger-associated molecular pattern associated with cell damage and induce BPI expression in a p38 dependent manner. These results are further supported by in vivo findings that the BPI expression in murine intestinal epithelium is induced upon infection with bacteria which cause intestinal damage (Salmonella Typhimurium and Shigella flexneri whereas mutants that do not cause intestinal damage (STM ΔfliC and STM ΔinvC did not induce BPI expression. Our results suggest that epithelial damage associated with infection act as a signal to induce BPI expression.

  12. Hydrogel increases localized transport regions and skin permeability during low frequency ultrasound treatment (United States)

    Pereira, Tatiana Aparecida; Ramos, Danielle Nishida; Lopez, Renata F. V.


    Low frequency ultrasound (LFU) enhances skin permeability via the formation of heterogeneous localized transport regions (LTRs). In this work, hydrogels with different zeta potentials were used as the coupling medium for LFU to investigate their contribution to LTR patterns and to the skin penetration of two model drugs, calcein and doxorubicin (DOX). When hydrogels were used, LTRs covering at least a 3-fold greater skin area were observed compared to those resulting from traditional LFU treatment and sodium lauryl sulfate. More LTRs resulted in an enhancement of calcein skin permeation. The zeta potential of the hydrogels affected the skin penetration of the positively charged DOX; the cationic coupling medium decreased the DOX recovered from the viable epidermis by 2.8-fold, whereas the anionic coupling medium increased the DOX accumulation in the stratum corneum by 4.4-fold. Therefore, LFU/hydrogel treatment increases LTRs areas and can target ionized drugs to specific skin layers depending on the zeta potential of the coupling medium.

  13. Brain pericytes from stress-susceptible pigs increase blood-brain barrier permeability in vitro

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    Vandenhaute Elodie


    Full Text Available Abstract Background The function of pericytes remains questionable but with improved cultured technique and the use of genetically modified animals, it has become increasingly clear that pericytes are an integral part of blood–brain barrier (BBB function, and the involvement of pericyte dysfunction in certain cerebrovascular diseases is now emerging. The porcine stress syndrome (PSS is the only confirmed, homologous model of malignant hyperthermia (MH in veterinary medicine. Affected animals can experience upon slaughter a range of symptoms, including skeletal muscle rigidity, metabolic acidosis, tachycardia and fever, similar to the human syndrome. Symptoms are due to an enhanced calcium release from intracellular stores. These conditions are associated with a point mutation in ryr1/hal gene, encoding the ryanodine receptor, a calcium channel. Important blood vessel wall muscle modifications have been described in PSS, but potential brain vessel changes have never been documented in this syndrome. Methods In the present work, histological and ultrastructural analyses of brain capillaries from wild type and ryr1 mutated pigs were conducted to investigate the potential impairment of pericytes, in this pathology. In addition, brain pericytes were isolated from the three porcine genotypes (wild-type NN pigs; Nn and nn pigs, bearing one or two (n mutant ryr1/hal alleles, respectively, and tested in vitro for their influence on the permeability of BBB endothelial monolayers. Results Enlarged perivascular spaces were observed in ryr1-mutant samples, corresponding to a partial or total detachment of the astrocytic endfeet. These spaces were electron lucent and sometimes filled with lipid deposits and swollen astrocytic feet. At the ultrastructural level, brain pericytes did not seem to be affected because they showed regular morphology and characteristics, so we aimed to check their ability to maintain BBB properties in vitro. Our results indicated

  14. Nitric oxide synthase inhibition causes acute increases in glomerular permeability in vivo, dependent upon reactive oxygen species. (United States)

    Dolinina, Julia; Sverrisson, Kristinn; Rippe, Anna; Öberg, Carl M; Rippe, Bengt


    There is increasing evidence that the permeability of the glomerular filtration barrier (GFB) is partly regulated by a balance between the bioavailability of nitric oxide (NO) and that of reactive oxygen species (ROS). It has been postulated that normal or moderately elevated NO levels protect the GFB from permeability increases, whereas ROS, through reducing the bioavailability of NO, have the opposite effect. We tested the tentative antagonism between NO and ROS on glomerular permeability in anaesthetized Wistar rats, in which the left ureter was cannulated for urine collection while simultaneously blood access was achieved. Rats were systemically infused with either l-NAME or l-NAME together with the superoxide scavenger Tempol, or together with l-arginine or the NO-donor DEA-NONOate, or the cGMP agonist 8-bromo-cGMP. To measure glomerular sieving coefficients (theta, θ) to Ficoll, rats were infused with FITC-Ficoll 70/400 (mol/radius 10-80 Å). Plasma and urine samples were analyzed by high-performance size-exclusion chromatography (HPSEC) for determination of θ for Ficoll repeatedly during up to 2 h. l-NAME increased θ for Ficoll70Å from 2.27 ± 1.30 × 10(-5) to 8.46 ± 2.06 × 10(-5) (n = 6, P permeability and an inhibition was also observed with l-arginine and with 8-bromo-cGMP. In conclusion, acute NO synthase inhibition in vivo by l-NAME caused rapid increases in glomerular permeability, which could be reversed by either an ROS antagonist or by activating the guanylyl cyclase-cGMP pathway. The data strongly suggest a protective effect of NO in maintaining normal glomerular permeability in vivo. Copyright © 2016 the American Physiological Society.

  15. Increased intestinal permeability correlates with sigmoid mucosa alpha-synuclein staining and endotoxin exposure markers in early Parkinson's disease.

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    Christopher B Forsyth

    Full Text Available Parkinson's disease (PD is the second most common neurodegenerative disorder of aging. The pathological hallmark of PD is neuronal inclusions termed Lewy bodies whose main component is alpha-synuclein protein. The finding of these Lewy bodies in the intestinal enteric nerves led to the hypothesis that the intestine might be an early site of PD disease in response to an environmental toxin or pathogen. One potential mechanism for environmental toxin(s and proinflammatory luminal products to gain access to mucosal neuronal tissue and promote oxidative stress is compromised intestinal barrier integrity. However, the role of intestinal permeability in PD has never been tested. We hypothesized that PD subjects might exhibit increased intestinal permeability to proinflammatory bacterial products in the intestine. To test our hypothesis we evaluated intestinal permeability in subjects newly diagnosed with PD and compared their values to healthy subjects. In addition, we obtained intestinal biopsies from both groups and used immunohistochemistry to assess bacterial translocation, nitrotyrosine (oxidative stress, and alpha-synuclein. We also evaluated serum markers of endotoxin exposure including LPS binding protein (LBP. Our data show that our PD subjects exhibit significantly greater intestinal permeability (gut leakiness than controls. In addition, this intestinal hyperpermeability significantly correlated with increased intestinal mucosa staining for E. coli bacteria, nitrotyrosine, and alpha-synuclein as well as serum LBP levels in PD subjects. These data represent not only the first demonstration of abnormal intestinal permeability in PD subjects but also the first correlation of increased intestinal permeability in PD with intestinal alpha-synuclein (the hallmark of PD, as well as staining for gram negative bacteria and tissue oxidative stress. Our study may thus shed new light on PD pathogenesis as well as provide a new method for earlier

  16. Design of vancomycin RS-100 nanoparticles in order to increase the intestinal permeability

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    Hadi Valizadeh


    Full Text Available Purpose: The purpose of this work was to preparation of vancomycin (VCM biodegradable nanoparticles to improve the intestinal permeability, using water-in-oil-in-water (W/O/W multiple emulsion method. Methods: The vancomycin-loaded nanoparticles were created using double-emulsion solvent evaporation method. Using Eudragit RS100 as a coating material. The prepared nanoparticles were identifyed for their micromeritic and crystallographic properties, drug loading, particle size, drug release, Zeta potential, effective permeability (Peff and oral fractional absorption. Intestinal permeability of VCM nanoparticles was figured out, in different concentrations using SPIP technique in rats. Results: Particle sizes were between 362 and 499 nm for different compositions of VCM-RS-100 nanoparticles. Entrapment efficiency expansed between 63%-94.76%. The highest entrapment efficiency 94.76% was obtained when the ratio of drug to polymer was 1:3. The in vitro release studies were accomplished in pH 7.4. The results showed that physicochemical properties were impressed by drug to polymer ratio. The FT-IR, XRPD and DSC results ruled out any chemical interaction betweenthe drug and RS-100. Effective intestinal permeability values of VCM nanoparticles in concentrations of 200, 300 and 400 µg/ml were higher than that of solutions at the same concentrations. Oral fractional absorption was achieved between 0.419-0.767. Conclusion: Our findings suggest that RS-100 nanoparticles could provide a delivery system for VCM, with enhanced intestinal permeability.

  17. Impaired innate immunity in the newborn: newborn neutrophils are deficient in bactericidal/permeability-increasing protein. (United States)

    Levy, O; Martin, S; Eichenwald, E; Ganz, T; Valore, E; Carroll, S F; Lee, K; Goldmann, D; Thorne, G M


    The mechanisms by which newborns are at increased risk for invasive bacterial infections have been incompletely defined. A central element of innate immunity to bacterial infection is the neutrophil-a cell that contains cytoplasmic granules replete with antibiotic proteins and peptides. The activity of adult neutrophils against gram-negative bacteria is believed to depend to a significant degree on the presence in neutrophil primary (azurophilic) granules of the 55-kDa bactericidal/permeability-increasing protein (BPI), which binds with high affinity to bacterial lipopolysaccharides and kills gram-negative bacteria. In light of the importance of BPI to antibacterial host defense and to investigate possible factors underlying the risk of neonatal bacterial infections, we determined the relative content of BPI in the neutrophils of adults and newborns. The cellular content of BPI was determined by Western blotting of neutrophils derived from full-term newborn cord blood (n = 21; mean gestational age: 38.6 weeks) and from adult peripheral blood (n = 22; mean age: 29 years). Extracellular levels of BPI in adult and newborn plasma were assessed by enzyme-linked immunosorbent assay. Neutrophil content of other azurophil granule markers also was assessed: myeloperoxidase by Western blotting and defensin peptides by acid-urea polyacrylamide gel electrophoresis and Coomassie staining. Acid extracts of newborn and adult neutrophils were analyzed for antibacterial activity against serum-resistant encapsulated isolate Escherichia coli K1/r. The neutrophils of newborns contain at least threefold to fourfold less BPI per cell than adult neutrophils (67 +/- 13 ng per 10(6) cells vs 234 +/- 27 ng per 10(6) cells). The relative BPI-deficiency of newborn neutrophils apparently was not attributable to perinatal stress-related degranulation of intracellular BPI stores because: 1) newborn and adult neutrophils contained nearly identical amounts of 2 microbicidal constituents derived

  18. Permeability enhancers dramatically increase zanamivir absolute bioavailability in rats: implications for an orally bioavailable influenza treatment.

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    Eric H Holmes

    Full Text Available We have demonstrated that simple formulations composed of the parent drug in combination with generally regarded as safe (GRAS permeability enhancers are capable of dramatically increasing the absolute bioavailability of zanamivir. This has the advantage of not requiring modification of the drug structure to promote absorption, thus reducing the regulatory challenges involved in conversion of an inhaled to oral route of administration of an approved drug. Absolute bioavailability increases of up to 24-fold were observed when Capmul MCM L8 (composed of mono- and diglycerides of caprylic/capric acids in glycerol was mixed with 1.5 mg of zanamivir and administered intraduodenally to rats. Rapid uptake (t(max of 5 min and a C(max of over 7200 ng/mL was achieved. Variation of the drug load or amount of enhancer demonstrated a generally linear variation in absorption, indicating an ability to optimize a formulation for a desired outcome such as a targeted C(max for enzyme saturation. No absorption enhancement was observed when the enhancer was given 2 hr prior to drug administration, indicating, in combination with the observed tmax, that absorption enhancement is temporary. This property is significant and aligns well with therapeutic applications to limit undesirable drug-drug interactions, potentially due to the presence of other poorly absorbed polar drugs. These results suggest that optimal human oral dosage forms of zanamivir should be enteric-coated gelcaps or softgels for intraduodenal release. There continues to be a strong need and market for multiple neuraminidase inhibitors for influenza treatment. Creation of orally available formulations of inhibitor drugs that are currently administered intravenously or by inhalation would provide a significant improvement in treatment of influenza. The very simple GRAS formulation components and anticipated dosage forms would require low manufacturing costs and yield enhanced convenience. These results

  19. Matrix metalloproteinase 9-induced increase in intestinal epithelial tight junction permeability contributes to the severity of experimental DSS colitis (United States)

    Nighot, Prashant; Al-Sadi, Rana; Guo, Shuhong; Watterson, D. Martin; Ma, Thomas


    Recent studies have implicated a pathogenic role for matrix metalloproteinases 9 (MMP-9) in inflammatory bowel disease. Although loss of epithelial barrier function has been shown to be a key pathogenic factor for the development of intestinal inflammation, the role of MMP-9 in intestinal barrier function remains unclear. The aim of this study was to investigate the role of MMP-9 in intestinal barrier function and intestinal inflammation. Wild-type (WT) and MMP-9−/− mice were subjected to experimental dextran sodium sulfate (DSS) colitis by administration of 3% DSS in drinking water for 7 days. The mouse colonic permeability was measured in vivo by recycling perfusion of the entire colon using fluorescently labeled dextran. The DSS-induced increase in the colonic permeability was accompanied by an increase in intestinal epithelial cell MMP-9 expression in WT mice. The DSS-induced increase in intestinal permeability and the severity of DSS colitis was found to be attenuated in MMP-9−/− mice. The colonic protein expression of myosin light chain kinase (MLCK) and phospho-MLC was found to be significantly increased after DSS administration in WT mice but not in MMP-9−/− mice. The DSS-induced increase in colonic permeability and colonic inflammation was attenuated in MLCK−/− mice and MLCK inhibitor ML-7-treated WT mice. The DSS-induced increase in colonic surface epithelial cell MLCK mRNA was abolished in MMP-9−/− mice. Lastly, increased MMP-9 protein expression was detected within the colonic surface epithelial cells in ulcerative colitis cases. These data suggest a role of MMP-9 in modulation of colonic epithelial permeability and inflammation via MLCK. PMID:26514773

  20. Vascular endothelial growth factor is increased during the first 48 hours of human septic shock and correlates with vascular permeability.

    NARCIS (Netherlands)

    Pickkers, P.; Sprong, T.; Eijk, L.T. van; Hoeven, J.G. van der; Smits, P.; Deuren, M. van


    Meningococcal septic shock is an important cause of morbidity and mortality in children and young adults worldwide and is the prototypical gram-negative septic shock. One of the key factors in the development of shock is increased microvascular permeability. Vascular endothelial growth factor (VEGF)

  1. The Bacteriocin Lactococcin A Specifically Increases Permeability of Lactococcal Cytoplasmic Membranes in a Voltage-Independent, Protein-Mediated Manner

    NARCIS (Netherlands)



    Lactococcin A is a bacteriocin produced by Lactococcus lactis. Its structural gene has recently been cloned and sequenced (M. J. van Belkum. B. J. Hayema, R. E. Jeeninga, J. Kok, and G. Venema, Appl. Environ. Microbiol. 57:492-498, 1991). Purified lactococcin A increased the permeability of the

  2. Hypertension in rats is associated with an increased permeability of the colon to TMA, a gut bacteria metabolite. (United States)

    Jaworska, Kinga; Huc, Tomasz; Samborowska, Emilia; Dobrowolski, Leszek; Bielinska, Klaudia; Gawlak, Maciej; Ufnal, Marcin


    An increased blood trimethylamine N-oxide (TMAO) has emerged as a marker of cardiovascular mortality, however, the mechanisms of the increase are not clear. We evaluated if hypertension was associated with changes in the colon permeability to trimethylamine (TMA), a TMAO precursor. We did experiments on male, 24-26-week-old normotensive Wistar-Kyoto rats (WKY), spontaneously hypertensive rats (SHR) and SHR treated with enalapril, an antihypertensive drug (SHR-E). To check the colon permeability and liver TMA clearance, blood was collected from the portal vein and hepatic veins confluence, at baseline and after the intracolonic administration of TMA. Arterial blood pressure (BP) and intestinal blood flow (IBF) recordings and histological assessment of the colon were performed. SHR showed an increased gut-blood barrier permeability to TMA. Namely, at baseline SHR had a higher BP and portal blood TMA, but a lower IBF than WKY. After the intracolonic administration of TMA, SHR had a significantly higher portal blood TMA and higher TMA liver clearance than WKY. In SHR the arteriolar walls of the colon mucosa were significantly thicker than in WKY. Furthermore, SHR showed a significant decrease in the height of the mucosa. In contrast, SHR-E had lower portal blood TMA, lower BP and smaller thickness of arteriolar walls, but higher IBF than SHR, which indicates improved function of the gut-blood barrier in SHR-E. All groups had similar immunostaining of occludin and zonula occludens-1, markers of tight junctions. In conclusion, hypertensive rats show an increased permeability of the colon to TMA, which is accompanied by morphological and hemodynamic alterations in the colon. Therefore, cardiovascular diseases may be characterized by an increased permeability of the gut-blood barrier to bacterial metabolites such as TMA.

  3. Silver nanoparticles interact with the cell membrane and increase endothelial permeability by promoting VE-cadherin internalization

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    Sun, Xia; Shi, Junpeng; Zou, Xiaoyan; Wang, Chengcheng; Yang, Yi; Zhang, Hongwu, E-mail:


    Highlights: • Short-term exposure to AgNPs at low doses induces increase HUVECs monolayer permeability. • AgNPs interact with the cell membrane and increase endothelial permeability by promoting VE-Cadherin internalization. • Particle effect is a major factor leading to endothelial dysfunction. - Abstract: The toxicological risks of silver nanoparticles (AgNPs) have attracted widespread attention, and many studies have been published that have contributed to understanding AgNPs-induced toxicity. However, little attention has been paid to the low-dose effects of AgNPs and the related toxicological mechanism is still unclear. Here, we show that short-term exposure to AgNPs at low doses induces a substantial increase in human umbilical vein endothelial cells (HUVECs) monolayer permeability, whereas Ag ions at low doses do not induce an observable increase in monolayer permeability. This effect is independent of oxidative stress and apoptosis. Scanning electron microscopy confirms that AgNPs adhere to the cell membrane after 1 h exposure. Furthermore, adhesion of AgNPs to the cell membrane can trigger vascular endothelial (VE)-cadherin phosphorylation at Y658 followed by VE-cadherin internalization, which lead to the increase in endothelial monolayer permeability. Our data show that surface interactions of AgNPs with the cell membrane, in other words, the particle effect, is a major factor leading to endothelial dysfunction following low-dose and short-term exposure. Our findings will contribute to understanding the health effects and the toxicological mechanisms of AgNPs.

  4. Phosphatidylcholine reverses ethanol-induced increase in transepithelial endotoxin permeability and abolishes transepithelial leukocyte activation

    DEFF Research Database (Denmark)

    Mitscherling, K.; Volynets, V.; Parlesak, Alexandr


    disease (ALD). As impaired bile flow leads to endotoxemia and the bile component phosphatidylcholine (PC) is therapeutically active in ALD, we tested the hypothesis that conjugated primary bile salts (CPBS) and PC inhibit ethanol-enhanced transepithelial permeability of endotoxin and the subsequent...

  5. Phosphatidylcholine Reverses Ethanol-Induced Increase in Transepithelial Endotoxin Permeability and Abolishes Transepithelial Leukocyte Activation

    DEFF Research Database (Denmark)

    Mitzscherling, Katja; Volynets, Valentina; Parlesak, Alexandr


    ). As impaired bile flow leads to endotoxemia and the bile component phosphatidylcholine (PC) is therapeutically active in ALD, we tested the hypothesis that conjugated primary bile salts (CPBS) and PC inhibit ethanol-enhanced transepithelial permeability of endotoxin and the subsequent transepithelial...

  6. Leaky gut and mycotoxins: Aflatoxin B1 does not increase gut permeability in broiler chickens

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    Rosario eGalarza-Seeber


    Full Text Available Previous studies conducted in our laboratory have demonstrated that intestinal barrier function can be adversely affected by diet ingredients or feed restriction, resulting in increased intestinal inflammation-associated permeability. Two experiments were conducted in broilers to evaluate the effect of 3 concentrations of Aflatoxin B1 (AFB1; 2, 1.5 or 1 ppm on gastrointestinal leakage and liver bacterial translocation (BT. In Exp 1, 240 day-of-hatch male broilers were allocated in two groups, each group had six replicates of 20 chickens (n = 120/group: Control feed or feed + 2 ppm AFB1. In Exp 2, 240 day-of-hatch male broilers were allocated in three groups, each group had 5 replicates of 16 chickens (n = 80/group: Control feed; feed + 1 ppm AFB1; or feed + 1.5 ppm AFB1. In both experiments, chickens were fed starter (d1-d7 and grower diets (d8-d21 ad libitum and performance parameters were evaluated every week. At day 21, all chicks received an oral gavage dose of FITC-d (4.16 mg/kg 2.5h before collecting blood samples to evaluate gastrointestinal leakage of FITC-d. In Exp 2 a hematologic analysis was also performed. Liver sections were aseptically collected and cultured using TSA plates to determine BT. Cecal contents were collected to determine total cfu/g of Gram-negative bacteria; lactic acid bacteria (LAB or anaerobes by plating on selective media. In Exp 2, liver, spleen and bursa of Fabricius were removed to determine organ weight ratio, and also intestinal samples were obtained for morphometric analysis. Performance parameters, organ weight ratio and morphometric measurements were significantly different between control and AFB1 groups in both experiments. Gut leakage of FITC-d was not affected by the three concentrations of AFB1 evaluated (P > 0.05. Interestingly, a significant reduction in BT was observed in chickens that received 2 and 1 ppm AFB1. An increase (P < 0.05 in total aerobic bacteria, total Gram negatives, and total LAB

  7. Evaluation of the increase in permeability of the blood-brain barrier during tumor progression after pulsed focused ultrasound. (United States)

    Yang, Feng-Yi; Wang, Hsin-Ell; Lin, Guan-Liang; Lin, Hui-Hsien; Wong, Tai-Tong


    The purpose of this study was to evaluate the permeability of the blood-brain barrier after sonication by pulsed high-intensity focused ultrasound and to determine if such an approach increases the tumor:ipsilateral brain permeability ratio. F98 glioma-bearing Fischer 344 rats were injected intravenously with Evans blue with or without blood-tumor barrier disruption induced by transcranial pulsed high-intensity focused ultrasound. Sonication was applied at a frequency of 1 MHz with a 5% duty cycle and a repetition frequency of 1 Hz. The permeability of the blood-brain barrier was assessed by the extravasation of Evans blue. Contrast-enhanced magnetic resonance images were used to monitor the gadolinium deposition path associated with transcranial pulsed high-intensity focused ultrasound, and the influencing size and location was also investigated. In addition, whole brain histological analysis was performed. The results were compared by two-tailed unpaired t-test. The accumulation of Evans blue in brains and the tumor:ipsilateral brain permeability ratio of Evans blue were significantly increased after pulsed high-intensity focused ultrasound exposure. Evans blue injection followed by sonication showed an increase in the tumor:ipsilateral brain ratio of the target tumors (9.14:1) of about 2.23-fold compared with the control tumors (x4.09) on day 6 after tumor implantation. Magnetic resonance images showed that pulsed high-intensity focused ultrasound locally enhances the permeability of the blood-tumor barrier in the glioma-bearing rats. This method could allow enhanced synergistic effects with respect to other brain tumor treatment regimens.

  8. Roles of increased glycemic variability, GLP-1 and glucagon in hypoglycaemia after Roux-en-Y gastric bypass

    DEFF Research Database (Denmark)

    Tharakan, George; Behary, Preeshila; Wewer Albrechtsen, Nicolai Jacob


    Objective Roux-en-Y Gastric Bypass (RYGB) surgery is currently the most effective treatment for diabetes and obesity. An increasingly recognized complication of RYGB surgery is postprandial hypoglycemia (PPH). The pathophysiology of PPH remains unclear with multiple mechanisms suggested including...... nesidioblastosis, altered insulin clearance and increased glucagon-like-1 peptide (GLP-1) secretion. Whilst many PPH patients respond to dietary modification, some have severely disabling symptoms. Multiple treatments have been trialled ranging from acarbose, to both GLP-1 agonists and antagonists, even...... in insulin and GLP-1 concentration in patients who had hypoglycemia in response to an MMT (MMT Hypo) relative to those that did not (MMT Non-Hypo). There was a significantly increased glucagon secretion in the MMT Hypo group versus the Non-hypo group. No significant differences in oxyntomodulin, GIP...

  9. Increased postprandial energy expenditure may explain superior long term weight loss after Roux-en-Y gastric bypass compared to vertical banded gastroplasty.

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    Malin Werling

    Full Text Available BACKGROUND AND AIMS: Gastric bypass results in greater weight loss than Vertical banded gastroplasty (VBG, but the underlying mechanisms remain unclear. In addition to effects on energy intake the two bariatric techniques may differentially influence energy expenditure (EE. Gastric bypass in rats increases postprandial EE enough to result in elevated EE over 24 hours. This study aimed to investigate alterations in postprandial EE after gastric bypass and VBG in humans. METHODS: Fourteen women from a randomized clinical trial between gastric bypass (n = 7 and VBG (n = 7 were included. Nine years postoperatively and at weight stability patients were assessed for body composition and calorie intake. EE was measured using indirect calorimetry in a respiratory chamber over 24 hours and focused on the periods surrounding meals and sleep. Blood samples were analysed for postprandial gut hormone responses. RESULTS: Groups did not differ regarding body composition or food intake either preoperatively or at study visit. Gastric bypass patients had higher EE postprandially (p = 0.018 and over 24 hours (p = 0.048 compared to VBG patients. Postprandial peptide YY (PYY and glucagon like peptide 1 (GLP-1 levels were higher after gastric bypass (both p<0.001. CONCLUSIONS: Gastric bypass patients have greater meal induced EE and total 24 hours EE compared to VBG patients when assessed 9 years postoperatively. Postprandial satiety gut hormone responses were exaggerated after gastric bypass compared to VBG. Long-term weight loss maintenance may require significant changes in several physiological mechanisms which will be important to understand if non-surgical approaches are to mimic the effects of bariatric surgery.

  10. Increased postprandial energy expenditure may explain superior long term weight loss after Roux-en-Y gastric bypass compared to vertical banded gastroplasty. (United States)

    Werling, Malin; Olbers, Torsten; Fändriks, Lars; Bueter, Marco; Lönroth, Hans; Stenlöf, Kaj; le Roux, Carel W


    Gastric bypass results in greater weight loss than Vertical banded gastroplasty (VBG), but the underlying mechanisms remain unclear. In addition to effects on energy intake the two bariatric techniques may differentially influence energy expenditure (EE). Gastric bypass in rats increases postprandial EE enough to result in elevated EE over 24 hours. This study aimed to investigate alterations in postprandial EE after gastric bypass and VBG in humans. Fourteen women from a randomized clinical trial between gastric bypass (n = 7) and VBG (n = 7) were included. Nine years postoperatively and at weight stability patients were assessed for body composition and calorie intake. EE was measured using indirect calorimetry in a respiratory chamber over 24 hours and focused on the periods surrounding meals and sleep. Blood samples were analysed for postprandial gut hormone responses. Groups did not differ regarding body composition or food intake either preoperatively or at study visit. Gastric bypass patients had higher EE postprandially (p = 0.018) and over 24 hours (p = 0.048) compared to VBG patients. Postprandial peptide YY (PYY) and glucagon like peptide 1 (GLP-1) levels were higher after gastric bypass (both pGastric bypass patients have greater meal induced EE and total 24 hours EE compared to VBG patients when assessed 9 years postoperatively. Postprandial satiety gut hormone responses were exaggerated after gastric bypass compared to VBG. Long-term weight loss maintenance may require significant changes in several physiological mechanisms which will be important to understand if non-surgical approaches are to mimic the effects of bariatric surgery.

  11. Changes in intestinal microbiota composition and metabolism coincide with increased intestinal permeability in young adults under prolonged physiological stress. (United States)

    Karl, J Philip; Margolis, Lee M; Madslien, Elisabeth H; Murphy, Nancy E; Castellani, John W; Gundersen, Yngvar; Hoke, Allison V; Levangie, Michael W; Kumar, Raina; Chakraborty, Nabarun; Gautam, Aarti; Hammamieh, Rasha; Martini, Svein; Montain, Scott J; Pasiakos, Stefan M


    The magnitude, temporal dynamics, and physiological effects of intestinal microbiome responses to physiological stress are poorly characterized. This study used a systems biology approach and a multiple-stressor military training environment to determine the effects of physiological stress on intestinal microbiota composition and metabolic activity, as well as intestinal permeability (IP). Soldiers ( n = 73) were provided three rations per day with or without protein- or carbohydrate-based supplements during a 4-day cross-country ski-march (STRESS). IP was measured before and during STRESS. Blood and stool samples were collected before and after STRESS to measure inflammation, stool microbiota, and stool and plasma global metabolite profiles. IP increased 62 ± 57% (mean ± SD, P microbiota responses were characterized by increased α-diversity and changes in the relative abundance of >50% of identified genera, including increased abundance of less dominant taxa at the expense of more dominant taxa such as Bacteroides Changes in intestinal microbiota composition were linked to 23% of metabolites that were significantly altered in stool after STRESS. Together, pre-STRESS Actinobacteria relative abundance and changes in serum IL-6 and stool cysteine concentrations accounted for 84% of the variability in the change in IP. Findings demonstrate that a multiple-stressor military training environment induced increases in IP that were associated with alterations in markers of inflammation and with intestinal microbiota composition and metabolism. Associations between IP, the pre-STRESS microbiota, and microbiota metabolites suggest that targeting the intestinal microbiota could provide novel strategies for preserving IP during physiological stress. NEW & NOTEWORTHY Military training, a unique model for studying temporal dynamics of intestinal barrier and intestinal microbiota responses to stress, resulted in increased intestinal permeability concomitant with changes in

  12. Effect of acute, slightly increased intra-abdominal pressure on intestinal permeability and oxidative stress in a rat model.

    Directory of Open Access Journals (Sweden)

    Yuxin Leng

    Full Text Available INTRODUCTION: Intra-abdominal hypertension (IAH is known as a common, serious complication in critically ill patients. Bacterial translocation and permeability changes are considered the pathophysiological bases for IAH-induced enterogenic endotoxemia and subsequent multiorgan failure. Nevertheless, the effects of slightly elevated intra-abdominal pressures (IAPs on the intestinal mucosa and the associated mechanisms remain unclear. METHODS: To investigate the acute effects of different nitrogen pneumoperitoneum grades on colonic mucosa, male Sprague-Dawley rats were assigned to six groups with different IAPs (0 [control], 4, 8, 12, 16, and 20 mmHg, n = 6/group. During 90 min of exposure, we dynamically monitored the heart rate and noninvasive hemodynamic parameters. After gradual decompression, arterial blood gas analyses were conducted. Thereafter, structural injuries to the colonic mucosa were identified using light microscopy. Colon permeability was determined using the expression of tight junction proteins, combined with fluorescein isothiocyanate dextran (FD-4 absorption. The pro-oxidant-antioxidant balance was determined based on the levels of malondialdehyde (MDA and antioxidant enzymes. RESULTS: IAH significantly affected the histological scores of the colonic mucosa, tight junction protein expression, mucosal permeability, and pro-oxidant-antioxidant balance. Interestingly, elevations of IAP that were lower than the threshold for IAH also showed a similar, undesirable effect. In the 8 mmHg group, mild hyponatremia, hypocalcemia, and hypoxemia occurred, accompanied by reduced blood and abdominal perfusion pressures. Mild microscopic inflammatory infiltration and increased MDA levels were also detected. Moreover, an 8-mm Hg IAP markedly inhibited the expression of tight junction proteins, although no significant differences in FD-4 permeability were observed between the 0- and 8-mmHg groups. CONCLUSIONS: Acute exposure to slightly

  13. The increased use of computed tomography angiography and magnetic resonance angiography as the sole imaging modalities prior to infrainguinal bypass has had no effect on outcomes. (United States)

    Shue, Bing; Damle, Rachelle N; Flahive, Julie; Kalish, Jeffrey A; Stone, David H; Patel, Virendra I; Schanzer, Andres; Baril, Donald T


    Angiography remains the gold standard imaging modality before infrainguinal bypass. Computed tomography angiography (CTA) and magnetic resonance angiography (MRA) have emerged as noninvasive alternatives for preoperative imaging. We sought to examine contemporary trends in the utilization of CTA and MRA as isolated imaging modalities before infrainguinal bypass and to compare outcomes following infrainguinal bypass in patients who underwent CTA or MRA versus those who underwent conventional arteriography. Patients undergoing infrainguinal bypass within the Vascular Study Group of New England were identified (2003-2012). Patients were stratified by preoperative imaging modality: CTA/MRA alone or conventional angiography. Trends in utilization of these modalities were examined and demographics of these groups were compared. Primary end points included primary patency, secondary patency, and major adverse limb events (MALE) at 1 year as determined by Kaplan-Meier analysis. Multivariable Cox proportional hazards models were constructed to evaluate the effect of imaging modality on primary patency, secondary patency, and MALE after adjusting for confounders. In 3123 infrainguinal bypasses, CTA/MRA alone was used in 462 cases (15%) and angiography was used in 2661 cases (85%). Use of CTA/MRA alone increased over time, with 52 (11%) bypasses performed between 2003 and 2005, 189 (41%) bypasses performed between 2006 and 2009, and 221 (48%) bypasses performed between 2010 and 2012 (P angiography, more frequently underwent bypass for claudication (33% vs. 26%, P = 0.001) or acute limb ischemia (13% vs. 5%, P < 0.0001), more frequently had prosthetic conduits (39% vs. 30%, P = 0.001), and less frequently had tibial/pedal targets (32% vs. 40%, P = 0.002). After adjusting for these and other confounders, multivariable analysis demonstrated that the use of CTA/MRA alone was not associated with a significant difference in 1 year primary patency (hazard ratio [HR] 0.95, 95

  14. Leucocyte depletion attenuates the early increase in myocardial capillary permeability to small hydrophilic solutes following ischaemia and reperfusion

    DEFF Research Database (Denmark)

    Svendsen, J H; Hansen, P R; Ali, S


    rate were quantitated in vivo by intracoronary indicator bolus injection and external registration of the washout, and the capillary permeability-surface area product was calculated. Postischaemic vasodilator tone in the myocardial resistance vessels was measured by the local 133xenon washout method...... reperfusion, the capillary extraction increased by 17% in the control group but decreased by 22% in the anti-PMN group (p maximum...

  15. Viperid Envenomation Wound Exudate Contributes to Increased Vascular Permeability via a DAMPs/TLR-4 Mediated Pathway (United States)

    Rucavado, Alexandra; Nicolau, Carolina A.; Escalante, Teresa; Kim, Junho; Herrera, Cristina; Gutiérrez, José María; Fox, Jay W.


    Viperid snakebite envenomation is characterized by inflammatory events including increase in vascular permeability. A copious exudate is generated in tissue injected with venom, whose proteomics analysis has provided insights into the mechanisms of venom-induced tissue damage. Hereby it is reported that wound exudate itself has the ability to induce increase in vascular permeability in the skin of mice. Proteomics analysis of exudate revealed the presence of cytokines and chemokines, together with abundant damage associated molecular pattern molecules (DAMPs) resulting from both proteolysis of extracellular matrix and cellular lysis. Moreover, significant differences in the amounts of cytokines/chemokines and DAMPs were detected between exudates collected 1 h and 24 h after envenomation, thus highlighting a complex temporal dynamic in the composition of exudate. Pretreatment of mice with Eritoran, an antagonist of Toll-like receptor 4 (TLR4), significantly reduced the exudate-induced increase in vascular permeability, thus suggesting that DAMPs might be acting through this receptor. It is hypothesized that an “Envenomation-induced DAMPs cycle of tissue damage” may be operating in viperid snakebite envenomation through which venom-induced tissue damage generates a variety of DAMPs which may further expand tissue alterations. PMID:27886127

  16. Experimental chronic cerebral hypoperfusion results in decreased pericyte coverage and increased blood-brain barrier permeability in the corpus callosum. (United States)

    Liu, Qinghai; Radwanski, Ryan; Babadjouni, Robin; Patel, Arati; Hodis, Drew M; Baumbacher, Peter; Zhao, Zhen; Zlokovic, Berislav; Mack, William J


    Murine chronic cerebral hypoperfusion (CCH) results in white matter (WM) injury and behavioral deficits. Pericytes influence blood-brain barrier (BBB) integrity and cerebral blood flow. Under hypoxic conditions, pericytes detach from perivascular locations increasing vessel permeability and neuronal injury. This study characterizes the time course of BBB dysfunction and pericyte coverage following murine experimental CCH secondary to bilateral carotid artery stenosis (BCAS). Mice underwent BCAS or sham operation. On post-procedure days 1, 3, 7 and 30, corpus callosum BBB permeability was characterized using Evans blue (EB) extravasation and IgG staining and pericyte coverage/count was calculated. The BCAS cohort demonstrated increased EB extravasation on postoperative days 1 ( p = 0.003) 3 ( p = 0.002), and 7 ( p = 0.001) when compared to sham mice. Further, EB extravasation was significantly greater ( p = 0.05) at day 3 than at day 30 in BCAS mice. BCAS mice demonstrated a nadir in pericyte coverage and count on post-operative day 3 ( p < 0.05, compared to day 7, day 30 and sham). Decreased pericyte coverage/count and increased BBB permeability are most pronounced on postoperative day 3 following murine CCH. This precedes any notable WM injury or behavioral deficits.

  17. Increased proliferation and decreased membrane permeability as defense mechanisms of Fusobacterium nucleatum against human neutrophilic peptide-1. (United States)

    Keskin, Mutlu; Könönen, Eija; Söderling, Eva; Isik, Gülden; Firatli, Erhan; Uitto, Veli-Jukka; Gürsoy, Ulvi Kahraman


    Human neutrophilic peptides (HNPs) constitute a class of host defense molecules, which contribute to the non-oxidative killing of bacteria and other microorganisms. Since the adaptability is crucial to bacterial survival in changing environments, it is of interest to know how Fusobacterium nucleatum, the major bridge organism connecting early and late colonizers in dental biofilms, defends itself against HNPs. This study aimed to examine the planktonic growth, membrane permeability, and biofilm formation characteristics as defense mechanisms of F. nucleatum against HNP-1. In all experiments, the type strain of F. nucleatum (ssp. nucleatum ATCC 25586) and two clinical strains (ssp. nucleatum AHN 9508 and ssp. polymorphum AHN 9910) were used. Planktonic growth (measured in colony forming units), capsular polysaccharide production (visualized by Ziehl-Neelsen stain), membrane permeability (demonstrated as N-phenyl-1-naphthylamine uptake), biofilm formation, and established biofilm development (measured as total mass and polysaccharide levels) were analyzed in the presence of 0 μg/ml (control), 1 μg/ml, 5 μg/ml, and 10 μg/ml of HNP-1. Planktonic growth of the strains AHN 9508 and ATCC 25586 were significantly (p<0.05) increased in the presence of HNP-1, while their membrane permeability decreased (p<0.005) in the planktonic form. HNP-1 decreased the biofilm formation of the strains ATCC 25586 and AHN 9910, whereas it increased the growth of the strain AHN 9508 in established biofilms. Capsule formation and polysaccharide production were not observed in any strain. We conclude that the inhibition of the membrane permeability and the increase in planktonic and established biofilm growth could act as bacterial defense mechanisms against neutrophilic defensins. In addition, this strain-dependent survival ability against HNP-1 may explain the variation in the virulence of different F. nucleatum strains. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Gliadin induces an increase in intestinal permeability and zonulin release by binding to the chemokine receptor CXCR3. (United States)

    Lammers, Karen M; Lu, Ruliang; Brownley, Julie; Lu, Bao; Gerard, Craig; Thomas, Karen; Rallabhandi, Prasad; Shea-Donohue, Terez; Tamiz, Amir; Alkan, Sefik; Netzel-Arnett, Sarah; Antalis, Toni; Vogel, Stefanie N; Fasano, Alessio


    Celiac disease is an immune-mediated enteropathy triggered by gliadin, a component of the grain protein gluten. Gliadin induces an MyD88-dependent zonulin release that leads to increased intestinal permeability, a postulated early element in the pathogenesis of celiac disease. We aimed to establish the molecular basis of gliadin interaction with intestinal mucosa leading to intestinal barrier impairment. Alpha-gliadin affinity column was loaded with intestinal mucosal membrane lysates to identify the putative gliadin-binding moiety. In vitro experiments with chemokine receptor CXCR3 transfectants were performed to confirm binding of gliadin and/or 26 overlapping 20mer alpha-gliadin synthetic peptides to the receptor. CXCR3 protein and gene expression were studied in intestinal epithelial cell lines and human biopsy specimens. Gliadin-CXCR3 interaction was further analyzed by immunofluorescence microscopy, laser capture microscopy, real-time reverse-transcription polymerase chain reaction, and immunoprecipitation/Western blot analysis. Ex vivo experiments were performed using C57BL/6 wild-type and CXCR3(-/-) mouse small intestines to measure intestinal permeability and zonulin release. Affinity column and colocalization experiments showed that gliadin binds to CXCR3 and that at least 2 alpha-gliadin 20mer synthetic peptides are involved in this binding. CXCR3 is expressed in mouse and human intestinal epithelia and lamina propria. Mucosal CXCR3 expression was elevated in active celiac disease but returned to baseline levels following implementation of a gluten-free diet. Gliadin induced physical association between CXCR3 and MyD88 in enterocytes. Gliadin increased zonulin release and intestinal permeability in wild-type but not CXCR3(-/-) mouse small intestine. Gliadin binds to CXCR3 and leads to MyD88-dependent zonulin release and increased intestinal permeability.

  19. Increased Permeability of the Aquaporin SoPIP2;1 by Mercury and Mutations in Loop A

    Directory of Open Access Journals (Sweden)

    Andreas Kirscht


    Full Text Available Aquaporins (AQPs also referred to as Major intrinsic proteins, regulate permeability of biological membranes for water and other uncharged small polar molecules. Plants encode more AQPs than other organisms and just one of the four AQP subfamilies in Arabidopsis thaliana, the water specific plasma membrane intrinsic proteins (PIPs, has 13 isoforms, the same number as the total AQPs encoded by the entire human genome. The PIPs are more conserved than other plant AQPs and here we demonstrate that a cysteine residue, in loop A of SoPIP2;1 from Spinacia oleracea, is forming disulfide bridges. This is in agreement with studies on maize PIPs, but in contrast we also show an increased permeability of mutants with a substitution at this position. In accordance with earlier findings, we confirm that mercury increase water permeability of both wild type and mutant proteins. We report on the slow kinetics and reversibility of the activation, and on quenching of intrinsic tryptophan fluorescence as a potential reporter of conformational changes associated with activation. Hence, previous studies in plants based on the assumption of mercury as a general aquaporin blocker have to be reevaluated, whereas mercury and fluorescence studies of isolated PIPs provide new means to follow structural changes dynamically.

  20. H2O2-induced endothelial NO production contributes to vascular cell apoptosis and increased permeability in rat venules (United States)

    Zhou, Xueping; Yuan, Dong; Wang, Mingxia


    Although elevated levels of H2O2 have been implicated to play important roles in the pathogenesis of various cardiovascular diseases, the underlying mechanisms remain unclear. This study aims to examine the effect of H2O2 on endothelial nitric oxide (NO) production in intact venules, and elucidate the role and mechanisms of NO in H2O2-induced increases in microvessel permeability. Experiments were conducted on individually perfused rat mesenteric venules. Microvessel permeability was determined by measuring hydraulic conductivity (Lp), and endothelial [Ca2+]i was measured on fura-2-loaded vessels. Perfusion of H2O2 (10 μM) caused a delayed and progressively increased endothelial [Ca2+]i and Lp, a pattern different from inflammatory mediator-induced immediate and transient response. Under the same experimental conditions, measuring endothelial NO via DAF-2 and the spatial detection of cell apoptosis by fluorescent markers revealed that H2O2 induced two phases of NO production followed by caspase activation, intracellular Ca2+ accumulation, and vascular cell apoptosis. The initial NO production was correlated with increased endothelial NO synthase (eNOS) Ser1177 phosphorylation in the absence of elevated endothelial [Ca2+]i, whereas the second phase of NO depended on increased [Ca2+]i and was associated with Thr495 dephosphorylation without increased Ser1177 phosphorylation. Inhibition of NOS prevented H2O2-induced caspase activation, cell apoptosis, and increases in endothelial [Ca2+]i and Lp. Our results indicate that H2O2 at micromolar concentration is able to induce a large magnitude of NO in intact venules, causing caspase activation-mediated endothelial Ca2+ accumulation, cell apoptosis, and increases in permeability. The mechanisms revealed from intact microvessels may contribute to the pathogenesis of oxidant-related cardiovascular diseases. PMID:23086988

  1. Mucosal biomarkers of colorectal cancer risk do not increase at 6 months following sleeve gastrectomy, unlike gastric bypass. (United States)

    Kant, Prashant; Perry, Sarah L; Dexter, Simon P; Race, Amanda D; Loadman, Paul M; Hull, Mark A


    The hypothesis that sleeve gastrectomy (SG) is not associated with an increase in mucosal colorectal cancer (CRC) biomarkers, unlike Roux-en-Y gastric bypass (RYGB), was tested. Rectal mucosa, blood, and urine were obtained from morbidly obese patients (n = 23) before and after (median 28 months) SG, as well as from nonobese controls (n = 20). Rectal epithelial cell mitosis and apoptosis, crypt size/fission, and pro-inflammatory gene expression were measured, as well as systemic inflammatory biomarkers, including C-reactive protein (CRP). The mean pre-operative body mass index in SG patients was 65.7 kg/m2 (24.7 kg/m2 in controls). Mean excess weight loss post-SG was 38.2%. There was a significant increase in mitosis frequency, crypt size, and crypt fission (all P risk do not increase at 6 months following SG, unlike RYGB. Biomarkers of rectal crypt proliferation and systemic inflammation are increased in morbidly obese patients compared with controls.

  2. Plasma cholecystokinin in obese patients before and after jejunoileal bypass with 3:1 or 1:3 jejunoileal ratio--no role in the increased risk of gallstone formation

    DEFF Research Database (Denmark)

    Sørensen, T I; Toftdahl, D B; Højgaard, L


    BACKGROUND AND AIM: Jejunoileal bypass surgery for obesity increases the risk of gallstone formation, and, contrary to expectations, the incidence is greater in patients with a long as compared to a short ileum left in continuity. Impaired gallbladder motility due to reduced cholecystokinin (CCK...... in plasma CCK levels neither explain the increased risk of gallstone formation after bypass surgery nor the higher incidence with a long compared to a short ileum left in continuity in the bypass....

  3. Early vascular injury and increased vascular permeability in gastric mucosal injury caused by ethanol in the rat. (United States)

    Szabo, S; Trier, J S; Brown, A; Schnoor, J


    The hypothesis that vascular injury contributes to the development of hemorrhagic erosions after intragastric administration of ethanol has been examined in the rat using vascular tracers. Extravasation of intravenously injected Evans blue into the gastric wall and into gastric contents was used as an indicator of vascular permeability. India ink and monastral blue, which label damaged blood vessels, were used to demonstrate vascular injury morphologically. Intragastric instillation of 75% and 100% ethanol induced increased vascular permeability within 1-3 min and resulted in monastral blue labeling of vessels in 13% and 17%, respectively, of the glandular mucosa within 1 min. After 1 h of 100% ethanol exposure, the areal density of monastral blue-stained blood vessels did not increase compared with that seen at 1 min, but the areal density of grossly visible hemorrhagic lesions increased strikingly and approximated that of vessel staining. The hemorrhagic erosions consistently occurred in regions of glandular mucosa where vessels were stained with monastral blue. Pretreatment with prostaglandin F2 beta or cysteamine reduced ethanol-induced Evans blue extravasation and monastral blue staining of mucosal blood vessels but did not reduce histologic evidence of gastric surface cell damage in the glandular mucosa. As increased vascular permeability and morphologically detectable vascular lesions consistently preceded the development of grossly visible hemorrhagic erosions in the glandular mucosa, we suggest that vascular injury is an early pathogenetic factor in the development of ethanol-induced gastric hemorrhagic erosions. The data also indicate that the degree of vascular damage, unlike the injury to surface epithelial cells, is reduced by pretreatment with prostaglandin F2 beta or the sulfhydryl cysteamine.

  4. Increasing Production from Low-Permeability Gas Reservoirs by Optimizing Zone Isolation for Successful Stimulation Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Fred Sabins


    Maximizing production from wells drilled in low-permeability reservoirs, such as the Barnett Shale, is determined by cementing, stimulation, and production techniques employed. Studies show that cementing can be effective in terms of improving fracture effectiveness by 'focusing' the frac in the desired zone and improving penetration. Additionally, a method is presented for determining the required properties of the set cement at various places in the well, with the surprising result that uphole cement properties in wells destined for multiple-zone fracturing is more critical than those applied to downhole zones. Stimulation studies show that measuring pressure profiles and response during Pre-Frac Injection Test procedures prior to the frac job are critical in determining if a frac is indicated at all, as well as the type and size of the frac job. This result is contrary to current industry practice, in which frac jobs are designed well before the execution, and carried out as designed on location. Finally, studies show that most wells in the Barnett Shale are production limited by liquid invasion into the wellbore, and determinants are presented for when rod or downhole pumps are indicated.

  5. Measurement of the filtration coefficient (Kfc) in the lung of Gallus domesticus and the effects of increased microvascular permeability. (United States)

    Weidner, W Jeffrey; Waddell, David S; Furlow, J David


    The filtration coefficient (Kfc) is a sensitive measure of microvascular hydraulic conductivity and has been reported for the alveolar lungs of many mammalian species, but not for the parabronchial avian lung. This study reports the Kfc in the isolated lungs of normal chickens and in the lungs of chickens given the edemogenic agents oleic acid (OA) or dimethyl amiloride (DMA). The control Kfc =0.04+/-0.01 ml min(-1) kPa(-1) g(-1). This parameter increased significantly following the administration of both OA (0.12+/-0.02 ml min(-1) kPa(-1) g(-1)) and DMA (0.07+/-0.01 ml min kPa(-1) g(-1)). As endothelial cadherins are thought to play a role in the dynamic response to acute lung injury, we utilized Western blot analysis to assess lung cadherin content and Northern blot analysis to assess pulmonary vascular endothelial (VE) cadherin expression following drug administration. Lung cadherin content decreases markedly following DMA, but not OA administration. VE cadherin expression increases as a result of DMA treatment, but is unchanged following OA. Our results suggest that the permeability characteristics of the avian lung are more closely consistent with those of the mammalian rather than the reptilian lung, and, that cadherins may play a significant role in the response to acute increases in avian pulmonary microvascular permeability.

  6. Medroxyprogesterone acetate and levonorgestrel increase genital mucosal permeability and enhance susceptibility to genital herpes simplex virus type 2 infection. (United States)

    Quispe Calla, N E; Vicetti Miguel, R D; Boyaka, P N; Hall-Stoodley, L; Kaur, B; Trout, W; Pavelko, S D; Cherpes, T L


    Depot-medroxyprogesterone acetate (DMPA) is a hormonal contraceptive especially popular in areas with high prevalence of HIV and other sexually transmitted infections (STI). Although observational studies identify DMPA as an important STI risk factor, mechanisms underlying this connection are undefined. Levonorgestrel (LNG) is another progestin used for hormonal contraception, but its effect on STI susceptibility is much less explored. Using a mouse model of genital herpes simplex virus type 2 (HSV-2) infection, we herein found that DMPA and LNG similarly reduced genital expression of the desmosomal cadherin desmoglein-1α (DSG1α), enhanced access of inflammatory cells to genital tissue by increasing mucosal epithelial permeability, and increased susceptibility to viral infection. Additional studies with uninfected mice revealed that DMPA-mediated increases in mucosal permeability promoted tissue inflammation by facilitating endogenous vaginal microbiota invasion. Conversely, concomitant treatment of mice with DMPA and intravaginal estrogen restored mucosal barrier function and prevented HSV-2 infection. Evaluating ectocervical biopsy tissue from women before and 1 month after initiating DMPA remarkably revealed that inflammation and barrier protection were altered by treatment identically to changes seen in progestin-treated mice. Together, our work reveals DMPA and LNG diminish the genital mucosal barrier; a first-line defense against all STI, but may offer foundation for new contraceptive strategies less compromising of barrier protection.

  7. On Blastocystis secreted cysteine proteases: a legumain-activated cathepsin B increases paracellular permeability of intestinal Caco-2 cell monolayers. (United States)

    Nourrisson, C; Wawrzyniak, I; Cian, A; Livrelli, V; Viscogliosi, E; Delbac, F; Poirier, P


    Blastocystis spp. pathogenic potential remains unclear as these anaerobic parasitic protozoa are frequently isolated from stools of both symptomatic and asymptomatic subjects. In silico analysis of the whole genome sequence of Blastocystis subtype 7 revealed the presence of numerous proteolytic enzymes including cysteine proteases predicted to be secreted. To assess the potential impact of proteases on intestinal cells and gut function, we focused our study on two cysteine proteases, a legumain and a cathepsin B, which were previously identified in Blastocystis subtype 7 culture supernatants. Both cysteine proteases were produced as active recombinant proteins. Activation of the recombinant legumain was shown to be autocatalytic and triggered by acidic pH, whereas proteolytic activity of the recombinant cathepsin B was only recorded after co-incubation with the legumain. We then measured the diffusion of 4-kDa FITC-labelled dextran across Caco-2 cell monolayers following exposition to either Blastocystis culture supernatants or each recombinant protease. Both Blastocystis culture supernatants and recombinant activated cathepsin B induced an increase of Caco-2 cell monolayer permeability, and this effect was significantly inhibited by E-64, a specific cysteine protease inhibitor. Our results suggest that cathepsin B might play a role in pathogenesis of Blastocystis by increasing intestinal cell permeability.

  8. Cardiotoxic drugs Herceptin and doxorubicin inhibit cardiac microvascular endothelial cell barrier formation resulting in increased drug permeability

    Directory of Open Access Journals (Sweden)

    Emma L. Wilkinson


    Full Text Available Cardiotoxicity induced by anti-cancer therapeutics is a severe, and potentially fatal, adverse reaction of the heart in response to certain drugs. Current in vitro approaches to assess cardiotoxicity have focused on analysing cardiomyocytes. More recently it has become apparent that non-cardiomyocyte cells of the heart can potentially contribute to cardiotoxicity. Herceptin and doxorubicin are known to induce cardiotoxicity in the clinic. The effect of these drugs on the endothelial tight junction barrier was tested by analysing tight junction formation and zona occludens-1 (ZO-1 levels, revealing that Herceptin and doxorubicin are able to induce barrier perturbment and decrease barrier function in human cardiac microvascular endothelial cells (HCMECs leading to increased permeability. Herceptin treatment had no effect on the tight junction barrier function in human dermal and human brain microvascular endothelial cells. HCMECs showed detectable levels of HER2 compared with the other endothelial cells suggesting that Herceptin binding to HER2 in these cells may interfere with tight junction formation. Our data suggests that doxorubicin and Herceptin can affect tight junction formation in the cardiac microvasculature leading to increased drug permeability and adverse effects on the cardiac myocytes.

  9. Photodynamic antimicrobial chemotherapy (PACT) inhibits biofilm formation by Candida albicans, increasing both ROS production and membrane permeability. (United States)

    Rosseti, Isabela Bueno; Chagas, Luciene Reginato; Costa, Maricilia Silva


    The opportunistic fungal Candida albicans is able to produce both superficial and systemic infections in immunocompromised patients. Photodynamic antimicrobial chemotherapy (PACT) is a process that combines visible light and a photosensitizer, producing reactive oxygen species (ROS) that can kill the treated cells and has been presented as a potential antimicrobial therapy. In this work, we study the effects of PACT, using toluidine blue (TB) as a photosensitizer drug, on ROS production and cell damage and the ability of C. albicans to form biofilm. A significant decrease was observed in the cell growth after PACT in a TB concentration-dependent manner. This effect was dependent on the incubation time after PACT. In addition, an increase in both the ROS production and cell permeability, after PACT, in a TB concentration-dependent manner was observed. PACT, using 0.1 mg/ml TB was able to reduce biofilm formation in 30, 50, and 62%, in cells submitted to incubation times of 1, 2, and 3 h, respectively. These results suggested that PACT, using TB, is able to decrease both growth and biofilm formation by C. albicans, possibly by a mechanism evolving both ROS production and the increase in the cell permeability.

  10. Placental ischemia-induced increases in brain water content and cerebrovascular permeability: role of TNF-α (United States)

    Warrington, Junie P.; Drummond, Heather A.; Granger, Joey P.


    Cerebrovascular complications and increased risk of encephalopathies are characteristic of preeclampsia and contribute to 40% of preeclampsia/eclampsia-related deaths. Circulating tumor necrosis factor-α (TNF-α) is elevated in preeclamptic women, and infusion of TNF-α into pregnant rats mimics characteristics of preeclampsia. While this suggests that TNF-α has a mechanistic role to promote preeclampsia, the impact of TNF-α on the cerebral vasculature during pregnancy remains unclear. We tested the hypothesis that TNF-α contributes to cerebrovascular abnormalities during placental ischemia by first infusing TNF-α in pregnant rats (200 ng/day ip, from gestational day 14 to 19) at levels to mimic those reported in preeclamptic women. TNF-α increased mean arterial pressure (MAP, P cerebral edema by increasing BBB permeability and is an underlying factor in the development of cerebrovascular abnormalities associated with preeclampsia complicated by placental ischemia. PMID:26400187

  11. Increased glucose-stimulated FGF21 response to oral glucose in obese non-diabetic subjects after Roux-en-Y Gastric Bypass

    DEFF Research Database (Denmark)

    Vienberg, Sara Gry; Jacobsen, Siv Hesse; Worm, Dorte


    fasting plasma FGF21 increased significantly after surgery. Furthermore, FGF21 levels increased significantly at t=90 and t=150 min in response to 50 g glucose, but not after a mixed meal. CONCLUSIONS: In conclusion, the observed increase in postprandial plasma FGF21 in response to glucose and the lack...... of FGF21 response to a mixed meal may have important implications for the physiologic role of FGF21. The increase in postprandial FGF21 in response to glucose in the early post-operative period may contribute to the metabolic improvements observed after gastric bypass. This article is protected......OBJECTIVE: The positive metabolic outcome of Roux-en-Y Gastric Bypass (RYGB) surgery may involve Fibroblast Growth Factor 21 (FGF21), both in the fasting state and postprandially. We measured the fasting levels of FGF21 before and after bariatric surgery as well as the postprandial FGF21 responses...

  12. Roux-en-Y gastric bypass increases hepatic and peripheral insulin sensitivity in rats with type 2 diabetes mellitus. (United States)

    He, Bing; Chen, Li; Yu, Cong; Piao, Dongxu; Wang, Yong; Han, Ping


    Roux-en-Y gastric bypass (RYGB) surgery for the treatment of obesity leads to long-term diabetes remission in approximately 80% of cases. The aim of this study was to investigate the effects of RYGB on hepatic and peripheral insulin sensitivity in type 2 diabetic rats and their possible mechanisms. We also tested the hypothesis that RYGB reduces lipid content and improves insulin sensitivity in hepatocytes and skeletal muscle cells. Sprague-Dawley rats were divided into 4 groups: diabetic RYGB group (n = 18), diabetic RYGB sham group (n = 6), diabetic group (n = 6), and nondiabetic control group (n = 6). The hyperinsulinemic-euglycemic clamp with tracer infusion was completed at 2, 4, and 8 weeks postoperatively to assess insulin sensitivity. The lipid content in liver and muscle tissue was examined. Postoperatively, the diabetic RYGB group had significant decreases in weight, fat mass, and food intake. Two weeks after surgery, RYGB had significantly improved the hepatic insulin sensitivity index and decreased the hepatic triglyceride, total cholesterol, and fatty acyl-CoA content. The significantly increased insulin sensitivity and decreased lipid content in muscle were not detected until 4 weeks after RYGB surgery. The basal insulin and C-peptide concentrations were significantly lower than those in diabetic group by 2 weeks after RYGB. The increased insulin sensitivity after RYGB occurs earlier in the liver than in the muscle and both may contribute to long-term remission of type 2 diabetes. Reduced lipid content of hepatocytes and skeletal muscle cells after RYGB may contribute to the improved insulin sensitivity in these cells. © 2013 Published by American Society for Metabolic and Bariatric Surgery on behalf of American Society for Bariatric Surgery.

  13. Perioperative clopidogrel is associated with increased bleeding and blood transfusion at the time of lower extremity bypass. (United States)

    Jones, Douglas W; Schermerhorn, Marc L; Brooke, Benjamin S; Conrad, Mark F; Goodney, Philip P; Wyers, Mark C; Stone, David H


    Controversy persists surrounding the perceived bleeding risk associated with perioperative clopidogrel use in patients undergoing lower extremity bypass (LEB). The purpose of this study was to examine the LEB bleeding risk and clinical sequelae associated with clopidogrel. All LEBs in the Vascular Quality Initiative (VQI) from 2008 to 2014 were studied. The exposure was perioperative clopidogrel. Primary outcomes were blood transfusion, estimated blood loss ≥500 mL, and reoperation for bleeding. Secondary outcomes included mean operative time, major cardiac events, respiratory complications, infectious complications, and in-hospital mortality. Univariate and multivariable analyses were used to analyze patients on the basis of clopidogrel use and its association with outcomes. Nonparametric test for trend and Mantel-Haenszel methods were used to analyze association of clopidogrel use with blood transfusion and secondary outcomes. Among the LEB cohort (N = 9179), 28% (n = 2544) were taking clopidogrel and 72% (n = 6635) were not. Patients taking clopidogrel were more likely to have coronary disease, prior coronary intervention, abnormal findings on stress test, and aspirin use (P blood transfusion (38% vs 24%; P blood loss ≥500 mL (21% vs 12%; P blood transfusion (odds ratio [OR], 1.8; 95% confidence interval [CI], 1.5-2.1; P 2-unit blood transfusion (OR, 2.0; 95% CI, 1.7-2.5; P blood transfusion amount revealed no remaining effect of clopidogrel on major cardiac events (OR, 1.1; P = .4) or respiratory complications (OR, 1.0; P = .8). Perioperative clopidogrel use in LEB surgery is associated with increased blood loss and blood transfusion. Associated clinical sequelae include increased cardiac and pulmonary complications. Accordingly, surgeons should consider discontinuation of perioperative clopidogrel when it is clinically appropriate unless it is strongly indicated at the time of LEB. Copyright © 2017 Society for Vascular Surgery. Published by

  14. Heart bypass surgery (United States)

    Off-pump coronary artery bypass; OPCAB; Beating heart surgery; Bypass surgery - heart; CABG; Coronary artery bypass graft; Coronary artery bypass surgery; Coronary bypass surgery; Coronary artery disease - CABG; CAD - CABG; Angina - ...

  15. Gastric bypass surgery (United States)

    ... Y gastric bypass; Gastric bypass - Roux-en-Y; Weight-loss surgery - gastric bypass; Obesity surgery - gastric bypass Patient Instructions Bathroom safety - adults Gastric bypass surgery - discharge Laparoscopic gastric banding - discharge ...

  16. Surfactant proteins A and D inhibit the growth of Gram-negative bacteria by increasing membrane permeability (United States)

    Wu, Huixing; Kuzmenko, Alexander; Wan, Sijue; Schaffer, Lyndsay; Weiss, Alison; Fisher, James H.; Kim, Kwang Sik; McCormack, Francis X.


    The pulmonary collectins, surfactant proteins A (SP-A) and D (SP-D), have been reported to bind lipopolysaccharide (LPS), opsonize microorganisms, and enhance the clearance of lung pathogens. In this study, we examined the effect of SP-A and SP-D on the growth and viability of Gram-negative bacteria. The pulmonary clearance of Escherichia coli K12 was reduced in SP-A–null mice and was increased in SP-D–overexpressing mice, compared with strain-matched wild-type controls. Purified SP-A and SP-D inhibited bacterial synthetic functions of several, but not all, strains of E. coli, Klebsiella pneumoniae, and Enterobacter aerogenes. In general, rough E. coli strains were more susceptible than smooth strains, and collectin-mediated growth inhibition was partially blocked by coincubation with rough LPS vesicles. Although both SP-A and SP-D agglutinated E. coli K12 in a calcium-dependent manner, microbial growth inhibition was independent of bacterial aggregation. At least part of the antimicrobial activity of SP-A and SP-D was localized to their C-terminal domains using truncated recombinant proteins. Incubation of E. coli K12 with SP-A or SP-D increased bacterial permeability. Deletion of the E. coli OmpA gene from a collectin-resistant smooth E. coli strain enhanced SP-A and SP-D–mediated growth inhibition. These data indicate that SP-A and SP-D are antimicrobial proteins that directly inhibit the proliferation of Gram-negative bacteria in a macrophage- and aggregation-independent manner by increasing the permeability of the microbial cell membrane. PMID:12750409

  17. Increased Thymic Cell Turnover under Boron Stress May Bypass TLR3/4 Pathway in African Ostrich. (United States)

    Huang, Hai-bo; Xiao, Ke; Lu, Shun; Yang, Ke-li; Ansari, Abdur Rahman; Khaliq, Haseeb; Song, Hui; Zhong, Juming; Liu, Hua-zhen; Peng, Ke-mei


    Previous studies revealed that thymus is a targeted immune organ in malnutrition, and high-boron stress is harmful for immune organs. African ostrich is the living fossil of ancient birds and the food animals in modern life. There is no report about the effect of boron intake on thymus of ostrich. The purpose of present study was to evaluate the effect of excessive boron stress on ostrich thymus and the potential role of TLR3/4 signals in this process. Histological analysis demonstrated that long-term boron stress (640 mg/L for 90 days) did not disrupt ostrich thymic structure during postnatal development. However, the numbers of apoptotic cells showed an increased tendency, and the expression of autophagy and proliferation markers increased significantly in ostrich thymus after boron treatment. Next, we examined the expression of TLR3 and TLR4 with their downstream molecular in thymus under boron stress. Since ostrich genome was not available when we started the research, we first cloned ostrich TLR3 TLR4 cDNA from thymus. Ostrich TLR4 was close to white-throated Tinamou. Whole avian TLR4 codons were under purify selection during evolution, whereas 80 codons were under positive selection. TLR3 and TLR4 were expressed in ostrich thymus and bursa of fabricius as was revealed by quantitative real-time PCR (qRT-PCR). TLR4 expression increased with age but significantly decreased after boron treatment, whereas TLR3 expression showed the similar tendency. Their downstream molecular factors (IRF1, JNK, ERK, p38, IL-6 and IFN) did not change significantly in thymus, except that p100 was significantly increased under boron stress when analyzed by qRT-PCR or western blot. Taken together, these results suggest that ostrich thymus developed resistance against long-term excessive boron stress, possibly by accelerating intrathymic cell death and proliferation, which may bypass the TLR3/4 pathway. In addition, attenuated TLRs activity may explain the reduced inflammatory

  18. Effects of diabetes and cardiopulmonary bypass on expression of adherens junction proteins in human peripheral tissue. (United States)

    Feng, Jun; Liu, Yuhong; Singh, Arun K; Ehsan, Afshin; Sellke, Nicholas; Liang, Justin; Sellke, Frank W


    We investigated the changes in adherens junction proteins, such as vascular endothelial-cadherin and β-catenin, of skeletal muscle and vessels in patients with or without diabetes in the setting of cardiopulmonary bypass and cardiac operation. Skeletal muscle tissue samples were harvested pre- and post-cardiopulmonary bypass from nondiabetic (hemoglobin A1c: 5.4 ± 0.1), controlled diabetic (hemoglobin A1c: 6.3 ± 0.1), and uncontrolled diabetic patients (hemoglobin A1c: 9.6 ± 0.3) undergoing coronary artery bypass grafting operation (n = 8 per group). The expression/phosphorylation of adherens junction proteins vascular endothelial-cadherin and β-catenin were assessed by immunoblotting and immuno-histochemistry. Endothelial function of skeletal muscle arterioles was determined by videomicroscopy in response to the vasodilator substance P. The protein expression of total vascular endothelial-cadherin was not changed at baseline or between pre-and post-cardiopulmonary bypass among groups. The pre-cardiopulmonary bypass level of phospho-vascular endothelial-cadherin was found to be significantly increased in the uncontrolled diabetic patients group compared with the nondiabetic or controlled diabetic groups (P cardiopulmonary bypass levels of phospho-vascular endothelial-cadherin were significantly increased compared with pre-cardiopulmonary bypass in all groups (P cardiopulmonary bypass in all 3 groups (P cardiopulmonary bypass in all 3 groups (P cardiopulmonary bypass. The enhanced phosphorylation of vascular endothelial-cadherin and degradation of β-catenin indicate deterioration of these proteins and damage of the cell-cell endothelial junctions, specifically in the diabetic peripheral vessels. These alterations may contribute to the increases in peripheral vascular permeability and endothelial dysfunction. Copyright © 2016 Elsevier Inc. All rights reserved.

  19. Pharmacological modulation of blood-brain barrier increases permeability of doxorubicin into the rat brain (United States)

    Sardi, Iacopo; la Marca, Giancarlo; Cardellicchio, Stefania; Giunti, Laura; Malvagia, Sabrina; Genitori, Lorenzo; Massimino, Maura; de Martino, Maurizio; Giovannini, Maria G


    Our group recently demonstrated in a rat model that pretreatment with morphine facilitates doxorubicin delivery to the brain in the absence of signs of increased acute systemic toxicity. Morphine and other drugs such as dexamethasone or ondansetron seem to inhibit MDR proteins localized on blood-brain barrier, neurons and glial cells increasing the access of doxorubicin to the brain by efflux transporters competition. We explored the feasibility of active modification of the blood-brain barrier protection, by using morphine dexamethasone or ondansetron pretreatment, to allow doxorubicin accumulation into the brain in a rodent model. Rats were pretreated with morphine (10 mg/kg, i.p.), dexamethasone (2 mg/kg, i.p.) or ondansetron (2 mg/kg, i.p.) before injection of doxorubicin (12 mg/kg, i.p.). Quantitative analysis of doxorubicin was performed by mass spectrometry. Acute hearth and kidney damage was analyzed by measuring doxorubicin accumulation, LDH activity and malondialdehyde plasma levels. The concentration of doxorubicin was significantly higher in all brain areas of rats pretreated with morphine (P < 0.001) or ondansetron (P < 0.05) than in control tissues. The concentration of doxorubicin was significantly higher in cerebral hemispheres and brainstem (P < 0.05) but not in cerebellum of rats pretreated with dexamethasone than in control tissues. Pretreatment with any of these drugs did not increase LDH activity or lipid peroxidation compared to controls. Our data suggest that morphine, dexamethasone or ondansetron pretreatment is able to allow doxorubicin penetration inside the brain by modulating the BBB. This effect is not associated with acute cardiac or renal toxicity. This finding might provide the rationale for clinical applications in the treatment of refractory brain tumors and pave the way to novel applications of active but currently inapplicable chemotherapeutic drugs. PMID:23977451

  20. Burn Injury Alters the Intestinal Microbiome and Increases Gut Permeability and Bacterial Translocation.

    Directory of Open Access Journals (Sweden)

    Zachary M Earley

    Full Text Available Sepsis remains one of the leading causes of death in burn patients who survive the initial insult of injury. Disruption of the intestinal epithelial barrier has been shown after burn injury; this can lead to the translocation of bacteria or their products (e.g., endotoxin from the intestinal lumen to the circulation, thereby increasing the risk for sepsis in immunocompromised individuals. Since the maintenance of the epithelial barrier is largely dependent on the intestinal microbiota, we examined the diversity of the intestinal microbiome of severely burned patients and a controlled mouse model of burn injury. We show that burn injury induces a dramatic dysbiosis of the intestinal microbiome of both humans and mice and allows for similar overgrowths of Gram-negative aerobic bacteria. Furthermore, we show that the bacteria increasing in abundance have the potential to translocate to extra-intestinal sites. This study provides an insight into how the diversity of the intestinal microbiome changes after burn injury and some of the consequences these gut bacteria can have in the host.

  1. Adrenaline increases blood-brain-barrier permeability after haemorrhagic cardiac arrest in immature pigs. (United States)

    Semenas, E; Sharma, H S; Wiklund, L


    Adrenaline (ADR) and vasopressin (VAS) are used as vasopressors during cardiopulmonary resuscitation. Data regarding their effects on blood-brain barrier (BBB) integrity and neuronal damage are lacking. We hypothesised that VAS given during cardiopulmonary resuscitation (CPR) after haemorrhagic circulatory arrest will preserve BBB integrity better than ADR. Twenty-one anaesthetised sexually immature male piglets (with a weight of 24.3 ± 1.3 kg) were bled 35% via femoral artery to a mean arterial blood pressure of 25 mmHg in the period of 15 min. Afterwards, the piglets were subjected to 8 min of untreated ventricular fibrillation followed by 15 min of open-chest CPR. At 9 min of circulatory arrest, piglets received amiodarone 1.0 mg/kg and hypertonic-hyperoncotic solution 4 ml/kg infusions for 20 min. At the same time, VAS 0.4 U/kg was given intravenously to the VAS group (n = 9) while the ADR group received ADR 20 μg/kg (n = 12). Internal defibrillation was attempted from 11 min of cardiac arrest to achieve restoration of spontaneous circulation. The experiment was terminated 3 h after resuscitation. The intracranial pressure (ICP) in the post-resuscitation phase was significantly greater in ADR group than in VAS group. VAS group piglets exhibited a significantly smaller BBB disruption compared with ADR group. Cerebral pressure reactivity index showed that cerebral blood flow autoregulation was also better preserved in VAS group. Resuscitation with ADR as compared with VAS after haemorrhagic circulatory arrest increased the ICP and impaired cerebrovascular autoregulation more profoundly, as well as exerted an increased BBB disruption though no significant difference in neuronal injury was observed. © 2014 The Acta Anaesthesiologica Scandinavica Foundation. Published by John Wiley & Sons Ltd.

  2. Increased permeability-oedema and atelectasis in pulmonary dysfunction after trauma and surgery: a prospective cohort study

    Directory of Open Access Journals (Sweden)

    Groeneveld AB Johan


    Full Text Available Abstract Background Trauma and surgery may be complicated by pulmonary dysfunction, acute lung injury (ALI and acute respiratory distress syndrome (ARDS, but the mechanisms are incompletely understood. Methods We evaluated lung capillary protein permeability non-invasively with help of the 67Ga-transferrin pulmonary leak index (PLI technique and extravascular lung water (EVLW by the transpulmonary thermal-dye dilution technique in consecutive, mechanically ventilated patients in the intensive care unit within 24 h of direct, blunt thoracic trauma (n = 5, 2 with ARDS, and within 12 h of indirect trauma by transhiatal oesophagectomy (n = 8, abdominal surgery for cancer (n = 6 and bone surgery (n = 4. We studied transfusion history, haemodynamics, oxygenation and mechanics of the lungs. The lung injury score (LIS, 0–4 was calculated. Plain radiography was also done to judge densities and atelectasis. Results The PLI and EVLW were elevated above normal in 61 and 30% of patients, respectively, and the PLI directly related to the number of red cell concentrates given (rs = 0.69, P s = 0.55, P = 0.007. Thoracic trauma patients had a worse oxygenation requiring higher airway pressures and thus higher LIS than the other patient groups, unrelated to PLI and EVLW but attributable to a higher cardiac output and thereby venous admixture. Finally, patients with radiographic signs of atelectasis had more impaired oxygenation and more densities than those without. Conclusion The oxygenation defect and radiographic densities in mechanically ventilated patients with pulmonary dysfunction and ALI/ARDS after trauma and surgery are likely caused by atelectasis rather than by increased permeability-oedema related to red cell transfusion.

  3. Inhibitory effect of the Ruscus extract and of the flavonoid hesperidine methylchalcone on increased microvascular permeability induced by various agents in the hamster cheek pouch. (United States)

    Bouskela, E; Cyrino, F Z; Marcelon, G


    The Ruscus extract and the flavonoid hesperidine methylchalcone (HMC) are used in treatment of venous insufficiency. In the present study, we used the hamster cheek pouch preparation and investigated the effects of these substances on increased microvascular permeability induced by bradykinin, histamine, and leukotriene B4 (LTB4) applied topically. Experiments were performed on male hamsters; 30 min after completion of the cheek pouch preparation, fluorescein-labeled dextran [molecular weight (mol wt) 150,000] was given intravenously (i.v.). Bradykinin, histamine, and LTB4 increased the number of fluorescent vascular leakage sites from postcapillary venules, evidence for an increase in macromolecular permeability, which was quantified in ultraviolet (UV)-light microscope as the number of leaky sites in the prepared area. Ruscus extract and HMC, given i.v., significantly inhibited the macromolecular permeability-increasing effect of bradykinin, LTB4, and histamine. Ruscus extract, applied topically, dose dependently inhibited the macromolecular permeability-increasing effect of histamine. Our results show that Ruscus extract and HMC have a protective effect against leakage of FITC-dextran in the cheek pouch after administration of various permeability-increasing substances, which further supports data previously reported on patients with venous insufficiency.

  4. Sex sorting increases the permeability of the membrane of stallion spermatozoa. (United States)

    Balao da Silva, C M; Ortega Ferrusola, C; Morillo Rodriguez, A; Gallardo Bolaños, J M; Plaza Dávila, M; Morrell, J M; Rodriguez Martínez, H; Tapia, J A; Aparicio, I M; Peña, F J


    At present, the only repeatable means of selecting the sex of offspring is the Beltsville semen sorting technology using flow cytometry (FC). This technology has reached commercial status in the bovine industry and substantial advances have occurred recently in swine and ovine species. In the equine species, however, the technology is not as well developed. To better understand the changes induced in stallion spermatozoa during the sorting procedure, pooled sperm samples were sorted: sperm motility and kinematics were assessed using computer assisted sperm analysis, sperm membrane integrity was assessed using the YoPro-1 assay, while plasmalemmal stability and lipid architecture were assessed using Merocyanine 540/SYTOX green and Annexin-V, respectively. Lipid peroxidation was also investigated with the probe Bodipy(581/591)-C11. All assays were performed shortly after collection, after incubation and after sex sorting using FC. In order to characterize potential molecular mechanisms implicated in sperm damage, an apoptosis protein antibody dot plot array analysis was performed before and after sorting. While the percentage of total motile sperm remained unchanged, sex sorting reduced the percentages of progressive motile spermatozoa and of rapid spermatozoa as well as curvilinear velocity (VCL). Sperm membranes responded to sorting with an increase in the percentage of YoPro-1 positive cells, suggesting the sorted spermatozoa had a reduced energy status that was confirmed by measuring intracellular ATP content. Copyright © 2013 Elsevier B.V. All rights reserved.

  5. Perioperative cardiovascular system failure in South Asians undergoing cardiopulmonary bypass is associated with prolonged inflammation and increased Toll-like receptor signaling in inflammatory monocytes. (United States)

    Trop, Sébastien; Marshall, John C; Mazer, C David; Gupta, Milan; Dumont, Daniel J; Bourdeau, Annie; Verma, Subodh


    South Asian ethnicity is an independent risk factor for mortality after coronary artery bypass. We tested the hypothesis that this risk results from a greater inflammatory response to cardiopulmonary bypass (CPB). This was a single-site prospective cohort study. We compared the inflammatory response to CPB in 20 Caucasians and 17 South Asians undergoing isolated coronary artery bypass grafting surgery. Plasma levels of proinflammatory cytokines (interleukin [IL]-6, IL-8, IL-12, interferon gamma, and tumor necrosis factor) and anti-inflammatory mediators (IL-10 and soluble TNF receptor I) were measured. The Toll-like receptor (TLR) signaling pathway was examined in peripheral blood monocytes by flow cytometry, measuring surface expression of TLR2, TLR4, and coreceptor CD14 and activation of downstream messenger molecules (interleukin-1 receptor-associated kinase 4, nuclear factor kappa from B cells (NF-κB), c-Jun amino-terminal kinase, p38 mitogen-activated protein kinase, and Protein Kinase B). South Asians had persistently higher plasma levels of IL-6 and exhibited increased TLR signaling through the p38 mitogen-activated protein kinase and Protein Kinase B pathways in inflammatory monocytes after CPB. This increased inflammatory response was paralleled clinically by a higher sequential organ failure assessment score (5.1 ± 1.4 versus 1.5 ± 1.6, P = 0.027) and prolonged cardiovascular system failure (23.5% versus 0%) 48 h after CPB. South Asians develop an exacerbated systemic inflammatory response after CPB, which may contribute to the higher morbidity and mortality associated with coronary artery bypass in this population. These patients may benefit from targeted anti-inflammatory therapies designed to mitigate the adverse consequences resulting from this response. Copyright © 2014 Elsevier Inc. All rights reserved.

  6. Porosity and permeability evolution of vesicular basalt reservoirs with increasing depth: constraints from the Big Island of Hawai'i (United States)

    Millett, John; Haskins, Eric; Thomas, Donald; Jerram, Dougal; Planke, Sverre; Healy, Dave; Kück, Jochem; Rossetti, Lucas; Farrell, Natalie; Pierdominici, Simona


    Volcanic reservoirs are becoming increasingly important in the targeting of petroleum, geothermal and water resources globally. However, key areas of uncertainty in relation to volcanic reservoir properties during burial in different settings remain. In this contribution, we present results from borehole logging and sampling operations within two fully cored c. 1.5 km deep boreholes, PTA2 and KMA1, from the Humúula saddle region on the Big Island of Hawai'i. The boreholes were drilled as part of the Humu'ula Groundwater Research Project (HGRP) between 2013-2016 and provide unique insights into the evolution of pore structure with increasing burial in a basaltic dominated lava sequence. The boreholes encounter mixed sequences of 'a'ā, pāhoehoe and transitional lava flows along with subsidiary intrusions and sediments from the shield to post-shield phases of Mauna Kea. Borehole wireline data including sonic, spectral gamma and Televiewer imagery were collected along with density, porosity, permeability and ultrasonic velocity laboratory measurements from core samples. A range of intra-facies were sampled for analysis from various depths within the two boreholes. By comparison with core data, the potential for high resolution Televiewer imaging to reveal spectacular intra-facies features including individual vesicles, vesicle segregations, 'a'ā rubble zones, intrusive contacts, and intricate pāhoehoe lava flow lobe morphologies is demonstrated. High quality core data enables the calibration of Televiewer facies enabling improved interpretation of volcanic reservoir features in the more common exploration scenario where core is absent. Laboratory results record the ability of natural vesicular basalt samples to host very high porosity (>50%) and permeability (>10 darcies) within lava flow top facies which we demonstrate are associated with vesicle coalescence and not micro-fractures. These properties may be maintained to depths of c. 1.5 km in regions of limited

  7. Heart bypass surgery - discharge (United States)

    Off-pump coronary artery bypass - discharge; OPCAB - discharge; Beating heart surgery - discharge; Bypass surgery - heart - discharge; CABG - discharge; Coronary artery bypass graft - discharge; Coronary artery ...

  8. Bactericidal/Permeability-increasing protein fold-containing family member A1 in airway host protection and respiratory disease. (United States)

    Britto, Clemente J; Cohn, Lauren


    Bactericidal/permeability-increasing protein fold-containing family member A1 (BPIFA1), formerly known as SPLUNC1, is one of the most abundant proteins in respiratory secretions and has been identified with increasing frequency in studies of pulmonary disease. Its expression is largely restricted to the respiratory tract, being highly concentrated in the upper airways and proximal trachea. BPIFA1 is highly responsive to airborne pathogens, allergens, and irritants. BPIFA1 actively participates in host protection through antimicrobial, surfactant, airway surface liquid regulation, and immunomodulatory properties. Its expression is modulated in multiple lung diseases, including cystic fibrosis, chronic obstructive pulmonary disease, respiratory malignancies, and idiopathic pulmonary fibrosis. However, the role of BPIFA1 in pulmonary pathogenesis remains to be elucidated. This review highlights the versatile properties of BPIFA1 in antimicrobial protection and its roles as a sensor of environmental exposure and regulator of immune cell function. A greater understanding of the contribution of BPIFA1 to disease pathogenesis and activity may clarify if BPIFA1 is a biomarker and potential drug target in pulmonary disease.

  9. Recombinant Treponema pallidum protein Tp0965 activates endothelial cells and increases the permeability of endothelial cell monolayer.

    Directory of Open Access Journals (Sweden)

    Rui-Li Zhang

    Full Text Available The recombinant Treponema pallidum protein Tp0965 (rTp0965, one of the many proteins derived from the genome of T. pallidum subsp. pallidum, shows strong immunogenicity and immunoreactivity. In this study, we investigated the effects of rTp0965 on the endothelial barrier. Treatment of human umbilical vein endothelial cells (HUVECs with rTp0965 resulted in increased levels of ICAM-1, E-selectin, and MCP-1 mRNA and protein expression. These increases contributed to the adhesion and chemataxis of monocytes (THP-1 cells to HUVECs preincubated with rTp0965. In addition, rTp0965 induced reorganization of F-actin and decreased expression of claudin-1 in HUVECs. Interestingly, inhibition of the RhoA/ROCK signal pathway protected against rTp0965-induced higher endothelial permeability as well as transendothelial migration of monocytes. These data indicate that Tp0965 protein may play an important role in the immunopathogenesis of syphilis.

  10. Leucocyte depletion attenuates the early increase in myocardial capillary permeability to small hydrophilic solutes following ischaemia and reperfusion

    DEFF Research Database (Denmark)

    Svendsen, Jesper Hastrup; Hansen, P R; Ali, S


    The aim was to assess the significance of polymorphonuclear leucocytes on the myocardial capillary permeability to a small hydrophilic indicator, on the vascular tone of the resistance vessels, and on contractile function following ischaemia and reperfusion....

  11. Radionuclide assessment of pulmonary microvascular permeability

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    Groeneveld, A.B.J. [Medical Intensive Care Unit, Department of Internal Medicine, Free University Hospital, De Boelelaan 1117, 1081 HV Amsterdam (Netherlands)


    The literature has been reviewed to evaluate the technique and clinical value of radionuclide measurements of microvascular permeability and oedema formation in the lungs. Methodology, modelling and interpretation vary widely among studies. Nevertheless, most studies agree on the fact that the measurement of permeability via pulmonary radioactivity measurements of intravenously injected radiolabelled proteins versus that in the blood pool, the so-called pulmonary protein transport rate (PTR), can assist the clinician in discriminating between permeability oedema of the lungs associated with the adult respiratory distress syndrome (ARDS) and oedema caused by an increased filtration pressure, for instance in the course of cardiac disease, i.e. pressure-induced pulmonary oedema. Some of the techniques used to measure PTR are also able to detect subclinical forms of lung microvascular injury not yet complicated by permeability oedema. This may occur after cardiopulmonary bypass and major vascular surgery, for instance. By paralleling the clinical severity and course of the ARDS, the PTR method may also serve as a tool to evaluate new therapies for the syndrome. Taken together, the currently available radionuclide methods, which are applicable at the bedside in the intensive care unit, may provide a gold standard for detecting minor and major forms of acute microvascular lung injury, and for evaluating the severity, course and response to treatment. (orig.). With 2 tabs.

  12. Zonulin transgenic mice show altered gut permeability and increased morbidity/mortality in the DSS colitis model. (United States)

    Sturgeon, Craig; Lan, Jinggang; Fasano, Alessio


    Increased small intestinal permeability (IP) has been proposed to be an integral element, along with genetic makeup and environmental triggers, in the pathogenies of chronic inflammatory diseases (CIDs). We identified zonulin as a master regular of intercellular tight junctions linked to the development of several CIDs. We aim to study the role of zonulin-mediated IP in the pathogenesis of CIDs. Zonulin transgenic Hp2 mice (Ztm) were subjected to dextran sodium sulfate (DSS) treatment for 7 days, followed by 4-7 days' recovery and compared to C57Bl/6 (wild-type (WT)) mice. IP was measured in vivo and ex vivo, and weight, histology, and survival were monitored. To mechanistically link zonulin-dependent impairment of small intestinal barrier function with clinical outcome, Ztm were treated with the zonulin inhibitor AT1001 added to drinking water in addition to DSS. We observed increased morbidity (more pronounced weight loss and colitis) and mortality (40-70% compared with 0% in WT) at 11 days post-DSS treatment in Ztm compared with WT mice. Both in vivo and ex vivo measurements showed an increased IP at baseline in Ztm compared to WT mice, which was exacerbated by DSS treatment and was associated with upregulation of zonulin gene expression (fourfold in the duodenum, sixfold in the jejunum). Treatment with AT1001 prevented the DSS-induced increased IP both in vivo and ex vivo without changing zonulin gene expression and completely reverted morbidity and mortality in Ztm. Our data show that zonulin-dependent small intestinal barrier impairment is an early step leading to the break of tolerance with subsequent development of CIDs. © 2017 New York Academy of Sciences.

  13. Coronary Artery Bypass Grafting (United States)

    ... Health Topics / Coronary Artery Bypass Grafting Coronary Artery Bypass Grafting What Is Coronary artery bypass grafting (CABG) ... multiple coronary arteries during one surgery. Coronary Artery Bypass Grafting Figure A shows the location of the ...

  14. Current peripheral bypass surgery: various clinical studies

    NARCIS (Netherlands)

    Slaa, Alexander te


    Substantial post-operative edema occurs in the majority of patients who undergo peripheral bypass surgery due to severe peripheral arterial disease (PAD). The pathophysiological mechanisms that underlay edema formation following peripheral bypass surgery include hyperemia, an increased capillary

  15. Consequences of increased vascular permeability induced by treatment of mice with 5,6-dimethylxanthenone-4-acetic acid (DMXAA) and thalidomide. (United States)

    Chung, Francisco; Liu, Jenny; Ching, Lai-Ming; Baguley, Bruce C


    5,6-Dimethylxanthenone-4-acetic acid (DMXAA) (AS1404), a small-molecule vascular disrupting agent currently in clinical trial, increases vascular permeability and decreases blood flow in both murine and human tumours. DMXAA induces tumour necrosis factor (TNF) in mice and the effects on vascular permeability are hypothesised to result from both direct (DMXAA) and indirect (TNF) effects. Skin temperature decreases in mice treated with high doses of DMXAA, raising the question of whether host toxicity is mediated by the induction of increased vascular permeability in normal tissue. Thalidomide is an anti-inflammatory agent that potentiates the anti-tumour activity of DMXAA but decreases induction of TNF in plasma. We wished to determine how it potentiated the effects of DMXAA. Vascular permeability was measured in Colon 38 tumour and liver tissue by uptake of Evans Blue dye. Blood haematocrit and body temperature were also measured. Tumour vascular permeability was increased following administration of DMXAA (25 mg/kg i.p.), minimally affected following thalidomide (100 mg/kg i.p.) but strongly increased following co-administration of both drugs. In contrast, dye uptake into liver tissue was decreased following administration of DMXAA, thalidomide or both drugs. Administration of DMXAA at a potentially toxic dose (35 mg/kg i.p. or 50 mg/kg orally) was found to decrease body temperature and to increase the blood haematocrit, while administration of thalidomide alone (100 mg/kg i.p.) had no effect. Co-administration of thalidomide potentiated the effects of DMXAA on both body temperature and haematocrit but surprisingly did not increase toxicity. The results are consistent with the hypothesis that the host toxicity of high-dose DMXAA is mediated by effects on host vasculature. Co-administration of thalidomide increases the effective dose of DMXAA by reducing clearance but also, by inhibiting production of circulating TNF, reduces the host toxicity of DMXAA.

  16. Accelerators increase permeability of cuticles for the lipophilic solutes metribuzin and iprovalicarb but not for hydrophilic methyl glucose. (United States)

    Shi, Tuansheng; Schönherr, Jörg; Schreiber, Lukas


    Effects of diethylsuberate (DESU), tributyl phosphate (TBP), and monodisperse ethoxylated alcohols (EAs) on rate constants of penetration (k) of model solutes across astomatous cuticular membranes isolated from Madagascar ivy (Stephanotis floribunda) and pear (Pyrus communis) leaves were studied. Model solutes (selected on the basis of their octanol/water partition coefficients, K(ow)) were iprovalicarb (log K(ow) = 3.18), metribuzin (log K(ow) = 1.60), and methyl glucose (MG) (log K(ow) = -3.0). K(ow) varied by more than 6 orders of magnitude. Accelerators had wax/water partition coefficients (log K(ww)) ranging from 1.75 (DESU) to 4.32 (C(12)E(2)), and their equilibrium concentrations in Stephanotis wax varied from 0 to about 160 g kg(-)(1). Accelerators increase solute mobility in cuticles by increasing fluidity of cutin and waxes. This effect was quantified by plotting log k versus the accelerator concentration in wax. With the lipophilic solutes metribuzin and iprovalicarb, these plots were linear. Slopes of these plots characterize the intrinsic activities of the accelerators, and they decreased in the order DESU (0.029) > TBP (0.015) > EAs (0.01). Using these intrinsic activities, the effects of accelerators on rate constants of penetration can be calculated for any accelerator concentration in wax. For instance, at 50 g kg(-)(1), rate constants for lipophilic solutes increased by factors of 28 (DESU), 5.6 (TBP), and 3.2 (C(12)E(n)()), respectively. Permeability of cuticles for the hydrophilic MG was not increased by DESU, TBP, C(12)E(2), and C(12)E(4), while C(12)E(6) and C(12)E(8) increased it. Small hydrophilic solutes such as MG can access aqueous pores in cuticles, and this pathway is not affected by changes in fluidity of amorphous waxes. After rate constants of penetration of ionic CaCl(2) were compared with those for nonionic MG, it was concluded that 60% of the MG diffused across aqueous pores, while 40% used an alternative pathway. Because the

  17. Gastric bypass surgery is followed by lowered blood pressure and increased diuresis - long term results from the Swedish Obese Subjects (SOS study.

    Directory of Open Access Journals (Sweden)

    Peter Hallersund

    Full Text Available OBJECTIVE: To compare two bariatric surgical principles with regard to effects on blood pressure and salt intake. BACKGROUND: In most patients bariatric surgery induces a sustained weight loss and a reduced cardiovascular risk profile but the long-term effect on blood pressure is uncertain. METHODS: Cohort study with data from the prospective, controlled Swedish Obese Subjects (SOS study involving 480 primary health care centres and 25 surgical departments in Sweden. Obese patients treated with non-surgical methods (Controls, n = 1636 and n = 1132 at 2 y and 10 y follow up, respectively were compared to patients treated with gastric bypass (GBP, n = 245 and n = 277, respectively or purely restrictive procedures (vertical banded gastroplasty or gastric banding; VBG/B, n = 1534 and n = 1064, respectively. RESULTS: At long-term follow-up (median 10 y GBP was associated with lowered systolic (mean: -5.1 mm Hg and diastolic pressure (-5.6 mmHg differing significantly from both VBG/B (-1.5 and -2.1 mmHg, respectively; p<0.001 and Controls (+1.2 and -3.8 mmHg, respectively; p<0.01. Diurnal urinary output was +100 ml (P<0.05 and +170 ml (P<0.001 higher in GBP subjects than in weight-loss matched VBG/B subjects at the 2 y and 10 y follow-ups, respectively. Urinary output was linearly associated with blood pressure only after GBP and these patients consumed approximately 1 g salt per day more at the follow-ups than did VBG/B (P<0.01. CONCLUSIONS: The purely restrictive techniques VBG/B exerted a transient blood pressure lowering effect, whereas gastric bypass was associated with a sustained blood pressure reduction and an increased diuresis. The daily salt consumption was higher after gastric bypass than after restrictive bariatric surgery.

  18. Crustal permeability (United States)

    Gleeson, Tom; Ingebritsen, Steven E.


    Permeability is the primary control on fluid flow in the Earth’s crust and is key to a surprisingly wide range of geological processes, because it controls the advection of heat and solutes and the generation of anomalous pore pressures.  The practical importance of permeability – and the potential for large, dynamic changes in permeability – is highlighted by ongoing issues associated with hydraulic fracturing for hydrocarbon production (“fracking”), enhanced geothermal systems, and geologic carbon sequestration.  Although there are thousands of research papers on crustal permeability, this is the first book-length treatment.  This book bridges the historical dichotomy between the hydrogeologic perspective of permeability as a static material property and the perspective of other Earth scientists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. 

  19. Sensitivity of K1-Encapsulated Escherichia coli to Killing by the Bactericidal/Permeability-Increasing Protein of Rabbit and Human Neutrophils


    Weiss, Jerrold; Victor, Michael; Cross, Alan S; Elsbach, Peter


    The presence of K1 capsular polysaccharides increases the resistance of Escherichia coli to killing by serum and phagocytosis by polymorphonuclear leukocytes (PMNs). To determine whether K1 capsule impedes the action of intracellular bactericidal systems of PMNs, we compared the sensitivity of several K1-encapsulated and non-encapsulated strains of E. coli to killing by the bactericidal/permeability-increasing protein (BPI) isolated from rabbit and human PMNs. BPI appears to be the principal ...

  20. The Interplay between Radioresistant Caco-2 Cells and the Immune System Increases Epithelial Layer Permeability and Alters Signaling Protein Spectrum (United States)

    Morini, Jacopo; Babini, Gabriele; Barbieri, Sofia; Baiocco, Giorgio; Ottolenghi, Andrea


    Colorectal cancer is one of the most frequent type of cancer, with a higher incidence in the developed countries. Colorectal cancer is usually managed with both surgeries, chemotherapy and radiotherapy. Radiotherapy has the well-known advantage of targeting the tumor, minimizing normal tissue exposure. Nevertheless, during radiation treatment, exposure of healthy tissues is of great concern, in particular because of the effects on the intestinal barrier functions and on cells belonging to the immune system. The functional role of intestinal barrier in avoiding paracellular trafficking and controlling bacterial spread from gut it is well known and it is due to the presence of tight junction complexes. However, intestinal barrier is fundamental in participating to the interplay with immune system, especially considering the gut-associated lymphoid tissue. Until few years ago, radiotherapy was considered to bear only a depressive action on the immune system. However, it is now recognized that the release of pro-inflammatory signals and phenotypic changes in tumoral cells due to ionizing radiation could trigger the immune system against the tumor. In this work, we address how intestinal barrier functions are perturbed by X-ray doses in the range 0–10 Gy, focusing on the interplay between tumoral cells and the immune system. To this aim, we adopted a coculture model in which Caco-2 cells can be grown in presence/absence of peripheral blood mononuclear cells (PBMC). We focused our attention on changes in the proliferation, trans-epithelial electrical resistance (TEER), cytokine release, and proteins of the junctional complexes. Our results indicate a high radioresistance of Caco-2 in the investigated dose range, and an increased permeability of the tumoral cell layer due to the presence of PBMC. This is found to be correlated with activation of PBMC, inhibiting the apoptotic pathway, with the enhancement of cytokine release and with variation of tight junction

  1. DHA-supplemented diet increases the survival of rats following asphyxia-induced cardiac arrest and cardiopulmonary bypass resuscitation. (United States)

    Kim, Junhwan; Yin, Tai; Shinozaki, Koichiro; Lampe, Joshua W; Becker, Lance B


    Accumulating evidence illustrates the beneficial effects of dietary docosahexaenoic acid (DHA) on cardiovascular diseases. However, its effects on cardiac arrest (CA) remain controversial in epidemiological studies and have not been reported in controlled animal studies. Here, we examined whether dietary DHA can improve survival, the most important endpoint in CA. Male Sprague-Dawley rats were randomized into two groups and received either a control diet or a DHA-supplemented diet for 7-8 weeks. Rats were then subjected to 20 min asphyxia-induced cardiac arrest followed by 30 min cardiopulmonary bypass resuscitation. Rat survival was monitored for additional 3.5 h following resuscitation. In the control group, 1 of 9 rats survived for 4 h, whereas 6 of 9 rats survived in the DHA-treated group. Surviving rats in the DHA-treated group displayed moderately improved hemodynamics compared to rats in the control group 1 h after the start of resuscitation. Rats in the control group showed no sign of brain function whereas rats in the DHA-treated group had recurrent seizures and spontaneous respiration, suggesting dietary DHA also protects the brain. Overall, our study shows that dietary DHA significantly improves rat survival following 20 min of severe CA.

  2. Poppet valve control of throat stability bypass to increase stable airflow range of a Mach 2.5. inlet with 60 percent internal contraction (United States)

    Mitchell, G. A.; Sanders, B. W.


    The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. System variations included several stability bypass entrance configurations. Poppet valves controlled the bypass airflow. The inlet stable airflow range achieved with each configuration was determined for both steady state conditions and internal pulse transients. Results are compared with those obtained without a stability bypass system. Transient results were also obtained for the inlet with a choke point at the diffuser exit and for the inlet with large and small stability bypass plenum volumes. Poppet valves at the stability bypass exit provided the inlet with a stable airflow range of 20 percent or greater at all static and transient conditions.

  3. Notional Permeability

    NARCIS (Netherlands)

    Kik, R.; Van den Bos, J.P.; Maertens, J.; Verhagen, H.J.; Van der Meer, J.W.


    Different layer design of a rock slope and under layers has a large effect on the strengths on the rock slope itself. In the stability formula developed of VAN DER MEER [1988] this effect is represented by the term Notional Permeability with symbol P. A more open, or permeable, structure underneath

  4. Protein kinase C activation modulates reversible increase in cortical blood–brain barrier permeability and tight junction protein expression during hypoxia and posthypoxic reoxygenation (United States)

    Willis, Colin L; Meske, Diana S; Davis, Thomas P


    Hypoxia (Hx) is a component of many disease states including stroke. Ischemic stroke occurs when there is a restriction of cerebral blood flow and oxygen to part of the brain. During the ischemic, and subsequent reperfusion phase of stroke, blood–brain barrier (BBB) integrity is lost with tight junction (TJ) protein disruption. However, the mechanisms of Hx and reoxygenation (HR)-induced loss of BBB integrity are not fully understood. We examined the role of protein kinase C (PKC) isozymes in modifying TJ protein expression in a rat model of global Hx. The Hx (6% O2) induced increased hippocampal and cortical vascular permeability to 4 and 10 kDa dextran fluorescein isothiocyanate (FITC) and endogenous rat-IgG. Cortical microvessels revealed morphologic changes in nPKC-θ distribution, increased nPKC-θ and aPKC-ζ protein expression, and activation by phosphorylation of nPKC-θ (Thr538) and aPKC-ζ (Thr410) residues after Hx treatment. Claudin-5, occludin, and ZO-1 showed disrupted organization at endothelial cell margins, whereas Western blot analysis showed increased TJ protein expression after Hx. The PKC inhibition with chelerythrine chloride (5 mg/kg intraperitoneally) attenuated Hx-induced hippocampal vascular permeability and claudin-5, PKC (θ and ζ) expression, and phosphorylation. This study supports the hypothesis that nPKC-θ and aPKC-ζ signaling mediates TJ protein disruption resulting in increased BBB permeability. PMID:20700133

  5. Alteration of Leukocyte Count Correlates With Increased Pulmonary Vascular Permeability and Decreased PaO2:FiO2 Ratio Early After Major Burns. (United States)

    Johansson, Joakim; Steinvall, Ingrid; Herwald, Heiko; Lindbom, Lennart; Sjöberg, Folke


    Leukocytes are activated systemically and their numbers increase soon after a burn followed by a rapid decline to low normal or subnormal levels, possibly by increased extravasation. Experimental data support that an important target for such extravasation is the lungs and that leukocytes when they adhere to endothelial cells cause an increase in vascular permeability. The authors investigated a possible relation between early increased pulmonary vascular permeability or a decreased PaO2:FiO2 ratio and the dynamic change in concentration of blood leukocytes after a burn. This is a prospective, exploratory, single-center study. The authors measured the dynamic changes of leukocytes in blood starting early after the burn, pulmonary vascular permeability index by thermodilution, and PaO2:FiO2-ratios in 20 patients during the first 21 days after a major burn (>20% TBSA%). Median TBSA was 40% interquartile range (IQR, 25-52) and full thickness burn 28% (IQR, 2-39). There was a correlation between the early (leukocytes and pulmonary failure early after burns.

  6. Dietary fat and bile juice, but not obesity, are responsible for the increase in small intestinal permeability induced through the suppression of tight junction protein expression in LETO and OLETF rats

    Directory of Open Access Journals (Sweden)

    Suzuki Takuya


    Full Text Available Abstract Background An increase in the intestinal permeability is considered to be associated with the inflammatory tone and development in the obesity and diabetes, however, the pathogenesis of the increase in the intestinal permeability is poorly understood. The present study was performed to determine the influence of obesity itself as well as dietary fat on the increase in intestinal permeability. Methods An obese rat strain, Otsuka Long Evans Tokushima Fatty (OLETF, and the lean counter strain, Long Evans Tokushima Otsuka (LETO, were fed standard or high fat diets for 16 weeks. Glucose tolerance, intestinal permeability, intestinal tight junction (TJ proteins expression, plasma bile acids concentration were evaluated. In addition, the effects of rat bile juice and dietary fat, possible mediators of the increase in the intestinal permeability in the obesity, on TJ permeability were explored in human intestinal Caco-2 cells. Results The OLETF rats showed higher glucose intolerance than did the LETO rats, which became more marked with the prolonged feeding of the high fat diet. Intestinal permeability in the OLETF rats evaluated by the urinary excretion of intestinal permeability markers (Cr-EDTA and phenolsulfonphthalein was comparable to that in the LETO rats. Feeding the high fat diet increased intestinal permeability in both the OLETF and LETO rats, and the increases correlated with decreases in TJ proteins (claudin-1, claudin-3, occludin and junctional adhesion molecule-1 expression in the small, but not in the large intestine (cecum or colon. The plasma bile acids concentration was higher in rats fed the high fat diet. Exposure to bile juice and the fat emulsion increased TJ permeability with concomitant reductions in TJ protein expression (claudin-1, claudin-3, and junctional adhesion molecule-1 in the Caco-2 cell monolayers. Conclusion Excessive dietary fat and/or increased levels of luminal bile juice, but not genetic obesity, are

  7. 2-aminoimidazoles potentiate ß-lactam antimicrobial activity against Mycobacterium tuberculosis by reducing ß-lactamase secretion and increasing cell envelope permeability.

    Directory of Open Access Journals (Sweden)

    Albert B Jeon

    Full Text Available There is an urgent need to develop new drug treatment strategies to control the global spread of drug-sensitive and multidrug-resistant Mycobacterium tuberculosis (M. tuberculosis. The ß-lactam class of antibiotics is among the safest and most widely prescribed antibiotics, but they are not effective against M. tuberculosis due to intrinsic resistance. This study shows that 2-aminoimidazole (2-AI-based small molecules potentiate ß-lactam antibiotics against M. tuberculosis. Active 2-AI compounds significantly reduced the minimal inhibitory and bactericidal concentrations of ß-lactams by increasing M. tuberculosis cell envelope permeability and decreasing protein secretion including ß-lactamase. Metabolic labeling and transcriptional profiling experiments revealed that 2-AI compounds impair mycolic acid biosynthesis, export and linkage to the mycobacterial envelope, counteracting an important defense mechanism reducing permeability to external agents. Additionally, other important constituents of the M. tuberculosis outer membrane including sulfolipid-1 and polyacyltrehalose were also less abundant in 2-AI treated bacilli. As a consequence of 2-AI treatment, M. tuberculosis displayed increased sensitivity to SDS, increased permeability to nucleic acid staining dyes, and rapid binding of cell wall targeting antibiotics. Transcriptional profiling analysis further confirmed that 2-AI induces transcriptional regulators associated with cell envelope stress. 2-AI based small molecules potentiate the antimicrobial activity of ß-lactams by a mechanism that is distinct from specific inhibitors of ß-lactamase activity and therefore may have value as an adjunctive anti-TB treatment.

  8. Human Lysozyme Synergistically Enhances Bactericidal Dynamics and Lowers the Resistant Mutant Prevention Concentration for Metronidazole to Helicobacter pylori by Increasing Cell Permeability

    Directory of Open Access Journals (Sweden)

    Xiaolin Zhang


    Full Text Available Metronidazole (MNZ is an effective agent that has been employed to eradicate Helicobacter pylori (H. pylori. The emergence of broad MNZ resistance in H. pylori has affected the efficacy of this therapeutic agent. The concentration of MNZ, especially the mutant prevention concentration (MPC, plays an important role in selecting or enriching resistant mutants and regulating therapeutic effects. A strategy to reduce the MPC that can not only effectively treat H. pylori but also prevent resistance mutations is needed. H. pylori is highly resistant to lysozyme. Lysozyme possesses a hydrolytic bacterial cell wall peptidoglycan and a cationic dependent mode. These effects can increase the permeability of bacterial cells and promote antibiotic absorption into bacterial cells. In this study, human lysozyme (hLYS was used to probe its effects on the integrity of the H. pylori outer and inner membranes using as fluorescent probe hydrophobic 1-N-phenyl-naphthylamine (NPN and the release of aspartate aminotransferase. Further studies using a propidium iodide staining method assessed whether hLYS could increase cell permeability and promote cell absorption. Finally, we determined the effects of hLYS on the bactericidal dynamics and MPC of MNZ in H. pylori. Our findings indicate that hLYS could dramatically increase cell permeability, reduce the MPC of MNZ for H. pylori, and enhance its bactericidal dynamic activity, demonstrating that hLYS could reduce the probability of MNZ inducing resistance mutations.

  9. Dietary soya saponins increase gut permeability and play a key role in the onset of soyabean-induced enteritis in Atlantic salmon ( Salmo salar L.). (United States)

    Knudsen, David; Jutfelt, Fredrik; Sundh, Henrik; Sundell, Kristina; Koppe, Wolfgang; Frøkiaer, Hanne


    Saponins are naturally occurring amphiphilic molecules and have been associated with many biological activities. The aim of the present study was to investigate whether soya saponins trigger the onset of soyabean-induced enteritis in Atlantic salmon (Salmo salar L.), and to examine if dietary soya saponins increase the epithelial permeability of the distal intestine in Atlantic salmon. Seven experimental diets containing different levels of soya saponins were fed to seawater-adapted Atlantic salmon for 53 d. The diets included a fishmeal-based control diet, two fishmeal-based diets with different levels of added soya saponins, one diet containing 25% lupin kernel meal, two diets based on 25% lupin kernel meal with different levels of added soya saponins, and one diet containing 25% defatted soyabean meal. The effect on intestinal morphology, intestinal epithelial permeability and faecal DM content was examined. Fish fed 25% defatted soyabean meal displayed severe enteritis, whereas fish fed 25% lupin kernel meal had normal intestinal morphology. The combination of soya saponins and fishmeal did not induce morphological changes but fish fed soya saponins in combination with lupin kernel meal displayed significant enteritis. Increased epithelial permeability was observed in fish fed 25% defatted soyabean meal and in fish fed soya saponin concentrate independent of the protein source in the feed. The study demonstrates that soya saponins, in combination with one or several unidentified components present in legumes, induce an inflammatory reaction in the distal intestine of Atlantic salmon. Soya saponins increase the intestinal epithelial permeability but do not, per se, induce enteritis.

  10. Dietary soya saponins increase gut permeability and play a key role in the onset of soyabean-induced enteritis in Atlantic salmon (Salmo salar L.)

    DEFF Research Database (Denmark)

    Knudsen, Sven David Lausten; Jutfelt, Fredrik; Sundh, Henrik


    are naturally occurring amphiphilic molecules and have been associated with many biological activities. The aim of the present study was to investigate whether soya saponins trigger the onset of soyabean-induced enteritis in Atlantic salmon (Salmo salar L.), and to examine if dietary soya saponins...... increase the epithelial permeability of the distal intestine in Atlantic salmon. Seven experimental diets containing different levels of soya saponins were fed to seawater-adapted Atlantic salmon for 53 d. The diets included a fishmeal-based control diet, two fishmeal-based diets with different levels...... of added soya saponins, one diet containing 25 % lupin kernel meal, two diets based on 25 % lupin kernel meal with different levels of added soya saponins, and one diet containing 25 % defatted soyabean meal. The effect on intestinal morphology, intestinal epithelial permeability and faecal DM content...

  11. Co action of CFTR and AQP1 increases permeability of peritoneal epithelial cells on estrogen-induced ovarian hyper stimulation syndrome

    Directory of Open Access Journals (Sweden)

    Jin Pei-Yin


    Full Text Available Abstract Background Ovarian hyper stimulation syndrome (OHSS is an iatrogenic complication associated with fertility drugs. It is characterized by increased vascular permeability and substantial fluid shift with accumulation in the body cavity. The pathogenesis of OHSS remains obscure, and no definitive treatments are currently available. Results Using western blot and short-circuit current (Isc techniques, we investigate the potential coactions of analysis in cystic fibrosis transmembrane conductance regulator (CFTR and aquaporin 1 (AQP1 on the hyper permeability of body cavity peritoneal epithelial cells in the pathogenesis of OHSS. The rats develop OHSS symptoms, with the up regulation of both CFTR and AQP1 expression and enhanced CFTR channel activity in peritoneal epithelial cells, can also be mimicked by administration of estrogen, alone in ovariectomized rats. Administration of progesterone suppresses CFTR activity, OHSS symptoms as well as CFTR and AQP1 expression. Besides, AQP1 inhibitor, HgCl2, can suppress CFTR channel activity. Therefore, antisera against CFTR or AQP1 to OHSS animals may result in alleviation of the symptom. Conclusion This study confirms the coactions of CFTR and AQP1 play a critical role in the development and progression of increased peritoneal epithelial permeability in severe OHSS. These findings may provide grounds for ameliorating assisted reproduction treatment strategy to reduce the risk of OHSS in in vitro fertilization (IVF.

  12. Melatonin attenuates the postischemic increase in blood-brain barrier permeability and decreases hemorrhagic transformation of tissue-plasminogen activator therapy following ischemic stroke in mice. (United States)

    Chen, Tsung-Ying; Lee, Ming-Yang; Chen, Hung-Yi; Kuo, Yen-Liang; Lin, Shih-Chieh; Wu, Tian-Shung; Lee, E-Jian


    Melatonin protects against transient middle cerebral artery (MCA) occlusion and may be suited as an add-on therapy of tissue plasminogen activator (t-PA) thrombolysis. Herein, we examined whether melatonin would reduce postischemic increase in the blood-brain barrier (BBB) permeability and, therefore, attenuate the risk of hemorrhagic transformation after t-PA therapy in experimental stroke. Twelve mice were subjected to transient occlusion of the MCA for 1 hr, followed by 24 hr of reperfusion. Melatonin (5 mg/kg, i.p.) or vehicle was given at the beginning of reperfusion. BBB permeability was evaluated by quantitation of Evans Blue leakage. An additional 32 mice underwent photothrombotic occlusion of the distal MCA, and were administered vehicle or t-PA (10 mg/kg, i.v.), alone or in combination with melatonin (5 mg/kg, i.p.), at 6 hr postinsult. The animals were then killed after 24 hr for the determination of infarct and hemorrhage volumes. Relative to controls, melatonin-treated animals had significantly reduced BBB permeability (by 52%; P hr after photo-irradiation, either t-PA or melatonin, or a combined administration of t-PA plus melatonin, did not significantly affect brain infarction (P > 0.05), compared with controls. Mice treated with t-PA alone, however, had significantly increased hemorrhagic formation (P transformation after t-PA therapy for ischemic stroke. The findings further highlight melatonin's potential role in the field of thrombolytic treatment for ischemic stroke patients.

  13. Permeable pavement study (Edison) (United States)

    U.S. Environmental Protection Agency — While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types...

  14. Pressure activated stability-bypass-control valves to increase the stable airflow range of a Mach 2.5 inlet with 40 percent internal contraction (United States)

    Mitchell, G. A.; Sanders, B. W.


    The throat of a Mach 2.5 inlet with a coldpipe termination was fitted with a stability-bypass system. The inlet stable airflow range provided by various stability-bypass entrance configurations in alternate combination with several stability-bypass exit controls was determined for both steady-state conditions and internal transient pulses. Transient results were also obtained for the inlet with a choke point at the diffuser exit. Instart angles of attack were determined for the various stability-bypass entrance configurations. The response of the inlet-coldpipe system to internal and external oscillating disturbances was determined. Poppet valves at the stability-bypass exit provided an inlet stable airflow range of 28 percent or greater at all static and transient conditions.

  15. The Microbiome Activates CD4 T-cell–mediated Immunity to Compensate for Increased Intestinal PermeabilitySummary

    Directory of Open Access Journals (Sweden)

    Karen L. Edelblum


    Full Text Available Background & Aims: Despite a prominent association, chronic intestinal barrier loss is insufficient to induce disease in human subjects or experimental animals. We hypothesized that compensatory mucosal immune activation might protect individuals with increased intestinal permeability from disease. We used a model in which intestinal barrier loss is triggered by intestinal epithelial-specific expression of constitutively active myosin light chain kinase (CA-MLCK. Here we asked whether constitutive tight junction barrier loss impacts susceptibility to enteric pathogens. Methods: Acute or chronic Toxoplasma gondii or Salmonella typhimurium infection was assessed in CA-MLCK transgenic or wild-type mice. Germ-free mice or those lacking specific immune cell populations were used to investigate the effect of microbial-activated immunity on pathogen translocation in the context of increased intestinal permeability. Results: Acute T gondii and S typhimurium translocation across the epithelial barrier was reduced in CA-MLCK mice. This protection was due to enhanced mucosal immune activation that required CD4+ T cells and interleukin 17A but not immunoglobulin A. The protective mucosal immune activation in CA-MLCK mice depended on segmented filamentous bacteria (SFB, because protection against early S typhimurium invasion was lost in germ-free CA-MLCK mice but could be restored by conventionalization with SFB-containing, not SFB-deficient, microbiota. In contrast, chronic S typhimurium infection was more severe in CA-MLCK mice, suggesting that despite activation of protective mucosal immunity, barrier defects ultimately result in enhanced disease progression. Conclusions: Increased epithelial tight junction permeability synergizes with commensal bacteria to promote intestinal CD4+ T-cell expansion and interleukin 17A production that limits enteric pathogen invasion. Keywords: Barrier Function, Tight Junction, Microbiota, CD4 T Cell, Mucosal Immunity

  16. Research and application of multi-hydrogen acidizing technology of low-permeability reservoirs for increasing water injection (United States)

    Ning, Mengmeng; Che, Hang; Kong, Weizhong; Wang, Peng; Liu, Bingxiao; Xu, Zhengdong; Wang, Xiaochao; Long, Changjun; Zhang, Bin; Wu, Youmei


    The physical characteristics of Xiliu 10 Block reservoir is poor, it has strong reservoir inhomogeneity between layers and high kaolinite content of the reservoir, the scaling trend of fluid is serious, causing high block injection well pressure and difficulty in achieving injection requirements. In the past acidizing process, the reaction speed with mineral is fast, the effective distance is shorter and It is also easier to lead to secondary sedimentation in conventional mud acid system. On this point, we raised multi-hydrogen acid technology, multi-hydrogen acid release hydrogen ions by multistage ionization which could react with pore blockage, fillings and skeletal effects with less secondary pollution. Multi-hydrogen acid system has advantages as moderate speed, deep penetration, clay low corrosion rate, wet water and restrains precipitation, etc. It can reach the goal of plug removal in deep stratum. The field application result shows that multi-hydrogen acid plug removal method has good effects on application in low permeability reservoir in Block Xiliu 10.

  17. Adipose tissue IL-8 is increased in normal weight women after menopause and reduced after gastric bypass surgery in obese women. (United States)

    Alvehus, Malin; Simonyte, Kotryna; Andersson, Therése; Söderström, Ingegerd; Burén, Jonas; Rask, Eva; Mattsson, Cecilia; Olsson, Tommy


    The menopausal transition is characterized by increased body fat accumulation, including redistribution from peripheral to central fat depots. This distribution is associated with an increased risk of type 2 diabetes and cardiovascular disease that are linked to low-grade inflammation. We determined whether postmenopausal women have higher levels of inflammatory markers, compared with premenopausal women. We also wanted to determine whether these markers are reduced by stable weight loss in obese women. Anthropometric data, blood samples and subcutaneous adipose tissue biopsies were collected from normal weight premenopausal and postmenopausal women and obese women before and 2 years after gastric bypass (GBP) surgery. Serum protein levels and adipose tissue gene expression of inflammatory markers were investigated. IL-8 expression in adipose tissue and circulating levels were higher in postmenopausal vs premenopausal women. IL-8 expression was associated with waist circumference, independent of menopausal status. IL-6 expression and serum levels of monocyte chemoattractant protein (MCP)-1 were higher in postmenopausal vs premenopausal women. Two years after GBP surgery, adipose expression of IL-8, tumour necrosis factor-α and MCP-1 decreased significantly. Serum insulin levels were associated with inflammation-related gene expression before GBP surgery, but these associations disappeared after surgery. Postmenopausal women have an increased inflammatory response in the subcutaneous fat and circulation. Inflammatory markers in adipose tissue decreased significantly after surgery-induced weight loss. This effect may be beneficial for metabolic control and reduced cardiovascular risk after weight loss. © 2011 Blackwell Publishing Ltd.

  18. Basic FGF enhances calcium permeable channel openings in adult rat cardiac myocytes: implication in the bFGF-induced increase of free Ca2+ content. (United States)

    Merle, P L; Usson, Y; Robert-Nicoud, M; Verdetti, J


    Basic fibroblast growth factor (bFGF) has been implicated in the changes in gene expression that, under pathological conditions such as ischemia or volume overload, lead to adult cardiomyocyte hypertrophy. In many tissues, one of the first events following cell activation by growth factors is an enhancement of the intracellular free calcium concentration, generated by fluxes from internal storage compartments and through channels of the plasma membrane. The present study was undertaken to determine whether cardiac myocytes isolated from adult rat ventricles express Ca2+-permeable channels activated by bFGF. Using the cell-attached mode of the patch-clamp technique, we observed that bFGF (from 0.1-10 nM) induced an increase of fast burst openings, mediated by Ca2+-permeable channels with low conductance (15 pS) and voltage-independence. Inside-out patch-clamp experiments revealed that inositol 1,4,5-trisphosphate (5 microM) enhanced the opening of Ca2+-permeable channels with similar properties as the bFGF-induced channels, indicating that IP3 may be a second messenger of this process. Confocal fluorescence imaging of intracellular free calcium provided direct evidence that bFGF induced an increase of cytoplasmic and nucleoplasmic free Ca2+ concentrations which were generated, in part, by Ca2+ influx through the plasma membrane. In conclusion, this study supports the presence, in the plasma membrane of adult cardiac myocytes, of messenger-activated calcium channels which could play key roles in the calcium-dependent pathways that are activated in response to growth factors. Copyright 1997 Academic Press Limited.

  19. Glioblastoma Treatment: Bypassing the Toxicity of Platinum Compounds by Using Liposomal Formulation and Increasing Treatment Efficiency With Concomitant Radiotherapy

    Energy Technology Data Exchange (ETDEWEB)

    Charest, Gabriel; Sanche, Leon [Center for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, Sherbrooke, Quebec (Canada); Fortin, David; Mathieu, David [Department of Surgery, Division of Neurosurgery, Centre Hospitalier Universitaire de Sherbrooke, Sherbrooke, Quebec (Canada); Paquette, Benoit, E-mail: [Center for Research in Radiotherapy, Department of Nuclear Medicine and Radiobiology, Universite de Sherbrooke, Sherbrooke, Quebec (Canada)


    Purpose: Treatments of glioblastoma with cisplatin or oxaliplatin only marginally improve the overall survival of patients and cause important side effects. To prevent adverse effects, improve delivery, and optimize the tumor response to treatment in combination with radiotherapy, a potential approach consists of incorporating the platinum agent in a liposome. Methods and Materials: In this study, cisplatin, oxaliplatin, carboplatin, Lipoplatin (the liposomal formulation of cisplatin), and Lipoxal (the liposomal formulation of oxaliplatin) were tested on F98 glioma orthotopically implanted in Fischer rats. The platinum compounds were administered by intracarotid infusion and were assessed for the ability to reduce toxicity, improve cancer cell uptake, and increase survival of animals when combined or not combined with radiotherapy. Results: The tumor uptake was 2.4-fold more important for Lipoxal than the liposome-free oxaliplatin. Lipoxal also improved the specificity of oxaliplatin as shown by a higher ratio of tumor to right hemisphere uptake. Surprisingly, Lipoplatin led to lower tumor uptake compared with cisplatin. However, Lipoplatin had the advantage of largely reducing the toxicity of cisplatin and allowed us to capitalize on the anticancer activity of this agent. Conclusion: Among the five platinum compounds tested, carboplatin showed the best increase in survival when combined with radiation for treatment of glioma implanted in Fischer rats.

  20. Permeability of displaced fractures (United States)

    Kluge, Christian; Milsch, Harald; Blöcher, Guido


    Flow along fractures or in fissured systems becomes increasingly important in the context of Enhanced Geothermal Systems (EGS), shale gas recovery or nuclear waste deposit. Commonly, the permeability of fractures is approximated using the Hagen-Poiseuille solution of Navier Stokes equation. Furthermore, the flow in fractures is assumed to be laminar flow between two parallel plates and the cubic law for calculating the velocity field is applied. It is a well-known fact, that fracture flow is strongly influenced by the fracture surface roughness and the shear displacement along the fracture plane. Therefore, a numerical approach was developed which calculates the flow pattern within a fracture-matrix system. The flow in the fracture is described by a free fluid flow and the flow in the matrix is assumed to be laminar and therefore validates Darcy's law. The presented approach can be applied for artificially generated fractures or real fractures measured by surface scanning. Artificial fracture surfaces are generated using the power spectral density of the surface height random process with a spectral exponent to define roughness. For calculating the permeability of such fracture-matrix systems the mean fracture aperture, the shear displacement and the surface roughness are considered by use of a 3D numerical simulator. By use of this approach correlation between shear displacement and mean aperture, shear displacement and permeability, as well as surface roughness and permeability can be obtained. Furthermore, the intrinsic measured permeability presents a combination of matrix and fracture permeability. The presented approach allows the separation and quantification of the absolute magnitudes of the matrix and the fracture permeability and the permeability of displaced fractures can be calculated. The numerical approach which is a 3D numerical simulation of the fracture-matrix system can be applied for artificial as well as real systems.

  1. Ischemia and reperfusion of the lung tissues induced increase of lung permeability and lung edema is attenuated by dimethylthiourea (PP69). (United States)

    Chen, K H; Chao, D; Liu, C F; Chen, C F; Wang, D


    This study sought to determine whether oxygen radical scavengers of dimethylthiourea (DMTU), superoxide dismutase (SOD), or catalase (CAT) pretreatment attenuated ischemia-reperfusion (I/R)-induced lung injury. After isolation from a Sprague-Dawley rat, the lungs were perfused through the pulmonary artery cannula with rat whole blood diluted 1:1 with a physiological salt solution. An acute lung injury was induced by 10 minutes of hypoxia with 5% CO2-95% N2 followed by 65 minutes of ischemia and then 65 minutes of reperfusion. I/R significantly increased microvascular permeability as measured by the capillary filtration coefficient (Kfc), lung weight-to-body weight ratio (LW/BW), and protein concentration in bronchoalveolar lavage fluid (PCBAL). DMTU pretreatment significantly attenuated the acute lung injury. The capillary filtration coefficient (P<.01), LW/BW (P<.01) and PCBAL (P<.05) were significantly lower among the DMTU-treated rats than hosts pretreated with SOD or CAT. The possible mechanisms of the protective effect of DMTU in I/R-induced lung injury may relate to the permeability of the agent allowing it to scavenge intracellular hydroxyl radicals. However, whether superoxide dismutase or catalase antioxidants showed protective effects possibly due to their impermeability of the cell membrane not allowing scavenging of intracellular oxygen radicals. Copyright (c) 2010 Elsevier Inc. All rights reserved.

  2. Studies on the potential neurotoxic and convulsant effects of increased blood levels of quinolinic acid in rats with altered blood-brain barrier permeability

    Energy Technology Data Exchange (ETDEWEB)

    Vezzani, A.; Stasi, M.A.; Wu, H.Q.; Castiglioni, M.; Weckermann, B.; Samanin, R. (Istituto di Ricerche Farmacologiche Mario Negri, Milano (Italy))


    Intravenous injection of 450 mg/kg quinolinic acid (Quin), an endogenous kynurenine metabolite with excitotoxic properties, induced only minor electroencephalographic (EEG) modifications and no neurotoxicity in rats with a mature blood-brain barrier (BBB). BBB permeability was altered in rats by focal unilateral irradiation of the cortex (7 mm in diameter and 5 mm in depth) with protons (60 Gy, 9 Gy/min). Three days after irradiation, Evans blue dye staining showed BBB breakdown in the dorsal hippocampus of the irradiated hemisphere. No neurotoxic or convulsant effects were observed as a consequence of the radiation itself. When BBB-lesioned rats were challenged with 225 mg/kg Quin iv, epileptiform activity was observed on EEG analysis. Tonic-clonic seizures were induced by 225-450 mg/kg Quin. Light microscopic analysis showed a dose-related excitotoxic type of lesion restricted to the hippocampus ipsilateral to the irradiated side. Neuro-degeneration was prevented by local injection of 120 nmol D(-)2-amino-7-phosphonoheptanoic acid, a selective N-methyl-D-aspartate receptor antagonist. No lesions or EEG or behavioral modifications occurred after 450 mg/kg nicotinic acid, an inactive analog of Quin. The potential neurotoxic and convulsant effects of increased blood levels of Quin under conditions of altered BBB permeability are discussed.

  3. Increasing Alfalfa Rumen Bypass Protein (United States)

    Alfalfa has one of the highest crude protein contents among forage crops, but is is rapidly and extensively degraded by rumen microorganisms. To examine differential protein digestion, three distinct varieties of alfalfa, grown from single plants, were subjected to fermentation in the rumen of a ca...

  4. Gut microbiota after Roux-en-Y gastric bypass and sleeve gastrectomy in a diabetic rat model: Increased diversity and associations of discriminant genera with metabolic changes. (United States)

    Guo, Yan; Liu, Chao-Qian; Shan, Cheng-Xiang; Chen, Yue; Li, Hui-Hua; Huang, Zhi-Ping; Zou, Da-Jin


    Recent work with gut microbiota after bariatric surgery is limited, and the results have not been in agreement. Given the role of the gut microbiota in regulating host metabolism, we explored the effect of Roux-en-Y gastric bypass (RYGB) and sleeve gastrectomy (SG) on the modifications of gut microbiota with regard to the potential influence of food intake and/or weight loss and examined their links with host metabolism. Zucker diabetic fatty rats were divided into the following groups: RYGB; sham-operated with pair-fed as RYGB; sham-operated fed ad libitum; and SG. The metabolic effects and gut microbiota profile were analyzed 10 weeks postoperatively. Associations between discriminating genera and metabolic markers after RYGB were explored. The 2 procedures induced similar glucose improvement and increased flora diversity after 10 weeks compared with sham-operated groups. RYGB induced a marked higher relative abundance of Proteobacteria/Gammaproteobacteria and Betaproteobacteria and increased emergence of Fusobacteria and Clostridium, whereas SG resulted in more abundant Actinobacteria compared with other groups. Most of the 12 discriminant genera correlated with changes in metabolic phenotype, but only 28.6% of these correlations were independent of weight, and 4 discriminant genera still negatively correlated with serum insulin level independent of food intake and weight loss after RYGB. These data demonstrate that RYGB and SG surgery produced similar diversity but different microbiota compositions changes in Zucker diabetic fatty rats. These findings stimulate deeper explorations of functions of the discriminate microbiota and the mechanisms linking postsurgical modulation of gut microbiota and improvements in insulin resistance. Copyright © 2016 John Wiley & Sons, Ltd.

  5. Roux-en-Y Gastric Bypass Surgery Suppresses Hepatic Gluconeogenesis and Increases Intestinal Gluconeogenesis in a T2DM Rat Model. (United States)

    Yan, Yong; Zhou, Zhou; Kong, Fanzhi; Feng, Suibin; Li, Xuzhong; Sha, Yanhua; Zhang, Guangjun; Liu, Haijun; Zhang, Haiqing; Wang, Shiguang; Hu, Cheng; Zhang, Xueli


    Roux-en-Y gastric bypass (RYGB) is an effective surgical treatment for type 2 diabetes mellitus (T2DM). The present study aimed to investigate the effects of RYGB on glucose homeostasis, lipid metabolism, and intestinal morphological adaption, as well as hepatic and intestinal gluconeogenesis. Twenty adult male T2DM rats induced by high-fat diet and low dose of streptozotocin were randomly divided into sham and RYGB groups. The parameters of body weight, food intake, glucose tolerance, insulin sensitivity, and serum lipid profiles were assessed to evaluate metabolic changes. Intestinal sections were stained with hematoxylin and eosin (H&E) for light microscopy examination. The messenger RNA (mRNA) and protein expression levels of key regulatory enzymes of gluconeogenesis [phosphoenolpyruvate carboxykinase (PEPCK), glucose-6-phosphatase (G6Pase)] were determined through reverse-transcription PCR (RT-PCR) and Western blotting, respectively. RYGB induced significant improvements in glucose tolerance and insulin sensitivity, along with weight loss and decreased food intake. RYGB also decreased serum triglyceride (TG) and free fatty acid (FFA) levels. The jejunum and ileum exhibited a marked increase in the length and number of intestinal villi after RYGB. The RYGB group exhibited downregulated mRNA and protein expression levels of PEPCK and G6Pase in the liver and upregulated expression of these enzymes in the jejunum and ileum tissues. RYGB ameliorates glucose and lipid metabolism accompanied by weight loss and calorie restriction. The small intestine shows hyperplasia and hypertrophy after RYGB. Meanwhile, our study demonstrated that the reduced hepatic gluconeogenesis and increased intestinal gluconeogenesis may contribute to improved glucose homeostasis after RYGB.

  6. Coronary Artery Bypass Surgery (United States)

    ... don't help, you may need coronary artery bypass surgery. The surgery creates a new path for ... narrowed area or blockage. This allows blood to bypass (get around) the blockage. Sometimes people need more ...

  7. Heart bypass surgery - slideshow (United States)

    ... page: // Heart bypass surgery - series—Normal anatomy To use the sharing ... Editorial team. Related MedlinePlus Health Topics Coronary Artery Bypass Surgery A.D.A.M., Inc. is accredited ...

  8. Coronary Artery Bypass (United States)

    ... to 3 days in the Intensive Care Unit (ICU). Life After Bypass After bypass surgery, your doctor will recommend that you join a cardiac rehabilitation program. These programs help you make lifestyle changes ...

  9. Variability of permeability with diameter of conduit

    Indian Academy of Sciences (India)

    ... creating a permeability profile similar to the velocity profile. An equation was obtained to establish this. We also found that peak values of permeability increase with increasing porosity, and therefore entry length increases with increasing porosity with all other parameters kept constant. A plot of peak permeability versus ...

  10. Gastric bypass reduces fat intake and preference (United States)

    Bueter, Marco; Theis, Nadine; Werling, Malin; Ashrafian, Hutan; Löwenstein, Christian; Athanasiou, Thanos; Bloom, Stephen R.; Spector, Alan C.; Olbers, Torsten; Lutz, Thomas A.


    Roux-en-Y gastric bypass is the most effective therapy for morbid obesity. This study investigated how gastric bypass affects intake of and preference for high-fat food in an experimental (rat) study and within a trial setting (human). Proportion of dietary fat in gastric bypass patients was significantly lower 6 yr after surgery compared with patients after vertical-banded gastroplasty (P = 0.046). Gastric bypass reduced total fat and caloric intake (P bypass rats displayed much lower preferences for Intralipid concentrations > 0.5% in an ascending concentration series (0.005%, 0.01%, 0.05%, 0.1%, 0.5%, 1%, 5%) of two-bottle preference tests (P = 0.005). This effect was demonstrated 10 and 200 days after surgery. However, there was no difference in appetitive or consummatory behavior in the brief access test between the two groups (P = 0.71) using similar Intralipid concentrations (0.005% through 5%). Levels of glucagon-like peptide-1 (GLP-1) were increased after gastric bypass as expected. An oral gavage of 1 ml corn oil after saccharin ingestion in gastric bypass rats induced a conditioned taste aversion. These findings suggest that changes in fat preference may contribute to long-term maintained weight loss after gastric bypass. Postingestive effects of high-fat nutrients resulting in conditioned taste aversion may partially explain this observation; the role of GLP-1 in mediating postprandial responses after gastric bypass requires further investigation. PMID:21734019

  11. Combined clopidogrel and aspirin treatment up to surgery increases the risk of postoperative myocardial infarction, blood loss and reoperation for bleeding in patients undergoing coronary artery bypass grafting. (United States)

    Miceli, Antonio; Duggan, Simon M J; Aresu, Giuseppe; de Siena, Paolo M; Romeo, Francesco; Glauber, Mattia; Caputo, Massimo; Angelini, Gianni D


    Recent guidelines suggest that patients undergoing coronary artery bypass grafting (CABG) should discontinue clopidogrel and aspirin (ASA) 5 and 2-10 days, respectively, before surgery to reduce postoperative bleeding and its complications. The aim of our study was to evaluate the relationship between the timing of discontinuing clopidogrel + ASA and early clinical outcomes in patients undergoing CABG. Four thousand three hundred and thirty consecutive patients underwent isolated CABG from April 2004 to February 2009. Of these, 926 patients received double antiplatelet therapy in the 14 days prior to surgery. Patients were stratified into three groups: clopidogrel + ASA within 5 and 2 days, respectively, before surgery (Group A, n = 287); clopidogrel within 5 days + ASA stopped 2-10 days before surgery or clopidogrel stopped 5 days + ASA within 2 days of surgery (Group B, n = 308) and clopidogrel + ASA discontinued >5 and 10 days, respectively, before surgery (control group, n = 331). Overall mortality was 0.8%. The incidence of postoperative myocardial infarction (MI) was 5.2, 1 and 1.8% in Groups A, B and control, respectively (P = 0.004). Reoperation for bleeding occurred in 4.5, 2.9 and 1.2% (P = 0.04) and total chest drainage was 761 ± 473, 720 ± 421 and 687 ± 302 ml in Groups A, B and control, respectively (P = 0.06). Multivariable analysis revealed that Group A was an independent predictor of postoperative MI (P = 0.02), reoperation for bleeding (P = 0.02), blood transfusions (P = 0.003) and blood losses (P = 0.015). Clopidogrel in combination with ASA up to the time of surgery is associated with an increased risk of postoperative MI, blood loss and reoperation for bleeding in patients undergoing CABG.

  12. Increased Atrial β-Adrenergic Receptors and GRK-2 Gene Expression Can Play a Fundamental Role in Heart Failure After Repair of Congenital Heart Disease with Cardiopulmonary Bypass. (United States)

    Oliveira, Marcela Silva; Carmona, Fabio; Vicente, Walter V A; Manso, Paulo H; Mata, Karina M; Celes, Mara Rúbia; Campos, Erica C; Ramos, Simone G


    Surgeries to correct congenital heart diseases are increasing in Brazil and worldwide. However, even with the advances in surgical techniques and perfusion, some cases, especially the more complex ones, can develop heart failure and death. A retrospective study of patients who underwent surgery for correction of congenital heart diseases with cardiopulmonary bypass (CPB) in a university tertiary-care hospital that died, showed infarction in different stages of evolution and scattered microcalcifications in the myocardium, even without coronary obstruction. CPB is a process routinely used during cardiac surgery for congenital heart disease. However, CPB has been related to increased endogenous catecholamines that can lead to major injuries in cardiomyocytes. The mechanisms involved are not completely understood. The aim of this study was to evaluate the alterations induced in the β-adrenergic receptors and GRK-2 present in atrial cardiomyocytes of infants with congenital heart disease undergoing surgical repair with CPB and correlate the alterations with functional and biochemical markers of ischemia/myocardial injury. The study consisted of right atrial biopsies of infants undergoing surgical correction in HC-FMRPUSP. Thirty-three cases were selected. Atrial biopsies were obtained at the beginning of CPB (group G1) and at the end of CPB (group G2). Real-time PCR, Western blotting, and immunofluorescence analysis were conducted to evaluate the expression of β 1 , β 2 -adrenergic receptors, and GRK-2 in atrial myocardium. Cardiac function was evaluated by echocardiography and biochemical analysis (N-terminal pro-brain natriuretic peptide (NT-ProBNP), lactate, and cardiac troponin I). We observed an increase in serum lactate, NT-proBNP, and troponin I at the end of CPB indicating tissue hypoxia/ischemia. Even without major clinical consequences in cardiac function, these alterations were followed by a significant increase in gene expression of β 1 and β 2

  13. Cloning of ovocalyxin-36, a novel chicken eggshell protein related to lipopolysaccharide-binding proteins, bactericidal permeability-increasing proteins, and plunc family proteins. (United States)

    Gautron, Joël; Murayama, Emi; Vignal, Alain; Morisson, Mireille; McKee, Marc D; Réhault, Sophie; Labas, Valérie; Belghazi, Maya; Vidal, Mary-Laure; Nys, Yves; Hincke, Maxwell T


    The avian eggshell is a composite biomaterial composed of noncalcifying eggshell membranes and the overlying calcified shell matrix. The shell is deposited in a uterine fluid where the concentration of different protein species varies at different stages of its formation. The role of avian eggshell proteins during shell formation remains poorly understood, and we have sought to identify and characterize the individual components in order to gain insight into their function during elaboration of the eggshell. In this study, we have used direct sequencing, immunochemistry, expression screening, and EST data base mining to clone and characterize a 1995-bp full-length cDNA sequence corresponding to a novel chicken eggshell protein that we have named Ovocalyxin-36 (OCX-36). Ovocalyxin-36 protein was only detected in the regions of the oviduct where egg-shell formation takes place; uterine OCX-36 message was strongly up-regulated during eggshell calcification. OCX-36 localized to the calcified eggshell predominantly in the inner part of the shell, and to the shell membranes. BlastN data base searching indicates that there is no mammalian version of OCX-36; however, the protein sequence is 20-25% homologous to proteins associated with the innate immune response as follows: lipopolysaccharide-binding proteins, bactericidal permeability-increasing proteins, and Plunc family proteins. Moreover, the genomic organization of these proteins and OCX-36 appears to be highly conserved. These observations suggest that OCX-36 is a novel and specific chicken eggshell protein related to the superfamily of lipopolysaccharide-binding proteins/bactericidal permeability-increasing proteins and Plunc proteins. OCX-36 may therefore participate in natural defense mechanisms that keep the egg free of pathogens.

  14. Effects of increased surface coverage of polyvinylpyrrolidone over a polysulfone hemofilter membrane on permeability and cell adhesion during continuous hemofiltration. (United States)

    Kokubo, Kenichi; Kurihara, Yoshitaka; Tsukao, Hiroshi; Maruyama, Naoko; Kobayashi, Kozue; Shinbo, Toshihiro; Hirose, Minoru; Kobayashi, Hirosuke


    The purpose of the present study was to evaluate the adhesiveness of blood cells and the solute removal performance change of modified polysulfone membranes which have increased polyvinylpyrrolidone (PVP) coverage over their surface. Continuous hemofiltration (CHF) experiments for 24 h were carried out using an ex vivo hemofilter evaluation system to compare a modified polysulfone hemofilter (SHG) with the conventional polysulfone hemofilter (SH). The 25 and 50 % cutoff values of the sieving coefficient of dextran after CHF and the protein concentration in the filtrate was higher in SHG, indicating that less fouling occurred in the SHG membrane. Adhesion of blood cells after 24 h of CHF was significantly higher in the case of SH than in the case of SHG. Blood cell adhesion and membrane fouling were reduced with the use of a polysulfone membrane modified with increased PVP coverage over the surface.

  15. Vascular Endothelial Growth Factor Increases during Blood-Brain Barrier-Enhanced Permeability Caused by Phoneutria nigriventer Spider Venom

    Directory of Open Access Journals (Sweden)

    Monique C. P. Mendonça


    Full Text Available Phoneutria nigriventer spider accidental envenomation provokes neurotoxic manifestations, which when critical, results in epileptic-like episodes. In rats, P. nigriventer venom (PNV causes blood-brain barrier breakdown (BBBb. The PNV-induced excitotoxicity results from disturbances on Na+, K+ and Ca2+ channels and glutamate handling. The vascular endothelial growth factor (VEGF, beyond its angiogenic effect, also, interferes on synaptic physiology by affecting the same ion channels and protects neurons from excitotoxicity. However, it is unknown whether VEGF expression is altered following PNV envenomation. We found that adult and neonates rats injected with PNV showed immediate neurotoxic manifestations which paralleled with endothelial occludin, β-catenin, and laminin downregulation indicative of BBBb. In neonate rats, VEGF, VEGF mRNA, and Flt-1 receptors, glutamate decarboxylase, and calbindin-D28k increased in Purkinje neurons, while, in adult rats, the BBBb paralleled with VEGF mRNA, Flk-1, and calbindin-D28k increases and Flt-1 decreases. Statistically, the variable age had a role in such differences, which might be due to age-related unequal maturation of blood-brain barrier (BBB and thus differential cross-signaling among components of the glial neurovascular unit. The concurrent increases in the VEGF/Flt-1/Flk-1 system in the cerebellar neuron cells and the BBBb following PNV exposure might imply a cytokine modulation of neuronal excitability consequent to homeostatic perturbations induced by ion channels-acting PNV neuropeptides. Whether such modulation represents neuroprotection needs further investigation.

  16. Permeable pavement study (Edison) (United States)

    While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types have on nutrient concentrations present in stormwater runoff are limited. In 2009, the U.S. EPA constructed a 0.4-ha parking lot in Edison, New Jersey, that incorporated permeable interlocking concrete pavement (PICP), pervious concrete (PC), and porous asphalt (PA). Each permeable pavement type has four, 54.9-m2, lined sections that direct all infiltrate into 5.7-m3 tanks enabling complete volume collection and sampling. This paper highlights the results from a 12-month period when samples were collected from 13 rainfall/runoff events and analyzed for nitrogen species, orthophosphate, and organic carbon. Differences in infiltrate concentrations among the three permeable pavement types were assessed and compared with concentrations in rainwater samples and impervious asphalt runoff samples, which were collected as controls. Contrary to expectations based on the literature, the PA infiltrate had significantly larger total nitrogen (TN) concentrations than runoff and infiltrate from the other two permeable pavement types, indicating that nitrogen leached from materials in the PA strata. There was no significant difference in TN concentration between runoff and infiltrate from either PICP or PC, but TN in runoff was significantly larger than in the rainwater, suggesting meaningful inter-event dry de

  17. Coronary Bypass Surgery in a 105-Year-Old Patient with Cardiopulmonary Bypass

    Directory of Open Access Journals (Sweden)

    Temucin Noyan Ogus


    Full Text Available Coronary artery bypass grafting is one of the routine daily surgical procedures in the current era. Parallel to the increasing life expectancy, cardiac surgery is commonly performed in octogenarians. However, literature consists of only seldom reports of coronary artery bypass grafting in patients above 90 years of age. In this report, we present our management strategy in a 105-year-old patient who underwent coronary artery bypass grafting at our institution.

  18. Bovine colostrum increases pore-forming claudin-2 protein expression but paradoxically not ion permeability possibly by a change of the intestinal cytokine milieu.

    Directory of Open Access Journals (Sweden)

    Peggy Bodammer

    Full Text Available An impaired intestinal barrier function is involved in the pathogenesis of inflammatory bowel disease (IBD. Several nutritional factors are supposed to be effective in IBD treatment but scientific data about the effects on the intestinal integrity remain scarce. Bovine colostrum was shown to exert beneficial effects in DSS-induced murine colitis, and the present study was undertaken to explore the underlying molecular mechanisms. Western blot revealed increased claudin-2 expression in the distal ileum of healthy mice after feeding with colostrum for 14 days, whereas other tight junction proteins (claudin-3, 4, 10, 15 remained unchanged. The colostrum-induced claudin-2 induction was confirmed in differentiated Caco-2 cells after culture with colostrum for 48 h. Paradoxically, the elevation of claudin-2, which forms a cation-selective pore, was neither accompanied by increased ion permeability nor impaired barrier function. In an in situ perfusion model, 1 h exposure of the colonic mucosa to colostrum induced significantly increased mRNA levels of barrier-strengthening cytokine transforming growth factor-β, while interleukine-2, interleukine-6, interleukine-10, interleukine-13, and tumor-necrosis factor-α remained unchanged. Thus, modulation of the intestinal transforming growth factor-β expression might have compensated the claudin-2 increase and contributed to the observed barrier strengthening effects of colostrum in vivo and in vitro.

  19. Respiratory uncoupling by increased H+ or K+ flux is beneficial for heart mitochondrial turnover of reactive oxygen species but not for permeability transition (United States)


    Background Ischemic preconditioning has been proposed to involve changes in mitochondrial H+ and K+ fluxes, in particular through activation of uncoupling proteins and ATP-sensitive K+ channels (MitoKATP). The objectives of the present study were to explore how increased H+ and K+ fluxes influence heart mitochondrial physiology with regard to production and scavenging of reactive oxygen species (ROS), volume changes and resistance to calcium-induced mitochondrial permeability transition (mPT). Results Isolated rat heart mitochondria were exposed to a wide concentration range of the protonophore CCCP or the potassium ionophore valinomycin to induce increased H+ and K+ conductance, respectively. Simultaneous monitoring of mitochondrial respiration and calcium retention capacity (CRC) demonstrated that the relative increase in respiration caused by valinomycin or CCCP correlated with a decrease in CRC, and that no level of respiratory uncoupling was associated with enhanced resistance to mPT. Mitochondria suspended in hyperosmolar buffer demonstrated a dose-dependent reduction in CRC with increasing osmolarity. However, mitochondria in hypoosmolar buffer to increase matrix volume did not display increased CRC. ROS generation was reduced by both K+- and H+-mediated respiratory uncoupling. The ability of heart mitochondria to detoxify H2O2 was substantially greater than the production rate. The H2O2 detoxification was dependent on respiratory substrates and was dramatically decreased following calcium-induced mPT, but was unaffected by uncoupling via increased K+ and H+ conductance. Conclusion It is concluded that respiratory uncoupling is not directly beneficial to rat heart mitochondrial resistance to calcium overload irrespective of whether H+ or K+ conductance is increased. The negative effects of respiratory uncoupling thus probably outweigh the reduction in ROS generation and a potential positive effect by increased matrix volume, resulting in a net sensitization

  20. Respiratory uncoupling by increased H(+) or K(+) flux is beneficial for heart mitochondrial turnover of reactive oxygen species but not for permeability transition. (United States)

    Morota, Saori; Piel, Sarah; Hansson, Magnus J


    Ischemic preconditioning has been proposed to involve changes in mitochondrial H(+) and K(+) fluxes, in particular through activation of uncoupling proteins and ATP-sensitive K(+) channels (MitoKATP). The objectives of the present study were to explore how increased H(+) and K(+) fluxes influence heart mitochondrial physiology with regard to production and scavenging of reactive oxygen species (ROS), volume changes and resistance to calcium-induced mitochondrial permeability transition (mPT). Isolated rat heart mitochondria were exposed to a wide concentration range of the protonophore CCCP or the potassium ionophore valinomycin to induce increased H(+) and K(+) conductance, respectively. Simultaneous monitoring of mitochondrial respiration and calcium retention capacity (CRC) demonstrated that the relative increase in respiration caused by valinomycin or CCCP correlated with a decrease in CRC, and that no level of respiratory uncoupling was associated with enhanced resistance to mPT. Mitochondria suspended in hyperosmolar buffer demonstrated a dose-dependent reduction in CRC with increasing osmolarity. However, mitochondria in hypoosmolar buffer to increase matrix volume did not display increased CRC. ROS generation was reduced by both K(+)- and H(+)-mediated respiratory uncoupling. The ability of heart mitochondria to detoxify H2O2 was substantially greater than the production rate. The H2O2 detoxification was dependent on respiratory substrates and was dramatically decreased following calcium-induced mPT, but was unaffected by uncoupling via increased K(+) and H(+) conductance. It is concluded that respiratory uncoupling is not directly beneficial to rat heart mitochondrial resistance to calcium overload irrespective of whether H(+) or K(+) conductance is increased. The negative effects of respiratory uncoupling thus probably outweigh the reduction in ROS generation and a potential positive effect by increased matrix volume, resulting in a net sensitization of

  1. The kinetics of denitrification in permeable sediments

    DEFF Research Database (Denmark)

    Evrard, Victor; Glud, Ronnie N.; Cook, Perran L. M.


    Permeable sediments comprise the majority of shelf sediments, yet the rates of denitrification remain highly uncertain in these environments. Computational models are increasingly being used to understand the dynamics of denitrification in permeable sediments, which are complex environments to st...

  2. Increase in blood-brain barrier permeability, oxidative stress, and activated microglia in a rat model of blast-induced traumatic brain injury. (United States)

    Readnower, Ryan D; Chavko, Mikulas; Adeeb, Saleena; Conroy, Michael D; Pauly, James R; McCarron, Richard M; Sullivan, Patrick G


    Traumatic brain injury (TBI) as a consequence of exposure to blast is increasingly prevalent in military populations, with the underlying pathophysiological mechanisms mostly unknown. In the present study, we utilized an air-driven shock tube to investigate the effects of blast exposure (120 kPa) on rat brains. Immediately following exposure to blast, neurological function was reduced. BBB permeability was measured using IgG antibody and evaluating its immunoreactivity in the brain. At 3 and 24 hr postexposure, there was a transient significant increase in IgG staining in the cortex. At 3 days postexposure, IgG immunoreactivity returned to control levels. Quantitative immunostaining was employed to determine the temporal course of brain oxidative stress following exposure to blast. Levels of 4-hydroxynonenal (4-HNE) and 3-nitrotyrosine (3-NT) were significantly increased at 3 hr postexposure and returned to control levels at 24 hr postexposure. The response of microglia to blast exposure was determined by autoradiographic localization of (3) H-PK11195 binding. At 5 days postexposure, increased binding was observed in the contralateral and ipsilateral dentate gyrus. These regions also displayed increased binding at 10 days postexposure; in addition to these regions there was increased binding in the contralateral ventral hippocampus and substantia nigra at this time point. By using antibodies against CD11b/c, microglia morphology characteristic of activated microglia was observed in the hippocampus and substantia nigra of animals exposed to blast. These results indicate that BBB breakdown, oxidative stress, and microglia activation likely play a role in the neuropathology associated with TBI as a result of blast exposure. Copyright © 2010 Wiley-Liss, Inc.

  3. Of Men Not Mice: Bactericidal/Permeability-Increasing Protein Expressed in Human Macrophages Acts as a Phagocytic Receptor and Modulates Entry and Replication of Gram-Negative Bacteria (United States)

    Balakrishnan, Arjun; Schnare, Markus; Chakravortty, Dipshikha


    Macrophages as immune cells prevent the spreading of pathogens by means of active phagocytosis and killing. We report here the presence of an antimicrobial protein, bactericidal/permeability-increasing protein (BPI) in human macrophages, which actively participates in engulfment and killing of Gram-negative pathogens. Our studies revealed increased expression of BPI in human macrophages during bacterial infection and upon stimulation with various pathogen-associated molecular patterns, viz., LPS and flagellin. Furthermore, during the course of an infection, BPI interacted with Gram-negative bacteria, resulting in enhanced phagocytosis and subsequent control of the bacterial replication. However, it was observed that bacteria which can maintain an active replicating niche (Salmonella Typhimurium) avoid the interaction with BPI during later stages of infection. On the other hand, Salmonella mutants, which cannot maintain a replicating niche, as well as Shigella flexneri, which quit the endosomal vesicle, showed interaction with BPI. These results propose an active role of BPI in Gram-negative bacterial clearance by human macrophages. PMID:27822215

  4. Intervention to increase the proportion of acute myocardial infarction or coronary artery bypass graft patients receiving an order for aspirin at hospital discharge. (United States)

    Brackbill, Marcia L; Kline, Vanessa T; Sytsma, Christine S; Call, Jason T


    Chronic aspirin therapy is recommended by the American College of Cardiology/American Heart Association (ACC/AHA) following acute myocardial infarction (AMI) and by the Society of Thoracic Surgeons(STS) following coronary artery bypass graft (CABG). Aspirin therapy at discharge following a hospitalization for AMI or CABG is a common pay for-performance indicator used by third-party payers and was included asa quality measure in the Centers for Medicare & Medicaid Services (CMS)/Premier Hospital Quality Incentive Demonstration initiated in 2003. A formal prescription for aspirin, such as required for other cardiovascular drugs,could serve as a reminder to all health care providers (doctors, nurses, and pharmacists) to include aspirin on a discharge medication list. To evaluate if an aspirin prescription placed in the patient chart shortly after hospital admission would increase compliance with guidelines for aspirin use at discharge in patients with AMI or CABG. This was a single-center prospective pre-intervention to post intervention comparison study in a 411-bed hospital. Patients admitted during the 3-month period from July through September 2008 with an AMI or undergoing CABG surgery served as the pre-intervention group, and patients admitted during the 3-month period from January through March 2009 were in the post-intervention group. The intervention included multiple educational sessions with clinical staff, conducted both prior to and during the pilot, and blank pre-printed aspirin prescriptions placed in the charts of patients for whom no contraindication to aspirin was present. The blank prescriptions were then completed by the attending physician (or physician extender), and the discharge nurse used the completed aspirin prescription, with other prescriptions and written orders, as a reference when creating the discharge medication list. The primary outcome measure was the percentage of patients who had aspirin documented on the discharge medication list

  5. A novel role for the bactericidal/permeability increasing protein in interactions of gram-negative bacterial outer membrane blebs with dendritic cells. (United States)

    Schultz, Hendrik; Hume, Janet; Zhang, De Sheng; Gioannini, Theresa L; Weiss, Jerrold P


    The bactericidal/permeability-increasing protein (BPI) is thought to play an important role in killing and clearance of Gram-negative bacteria and the neutralization of endotoxin. A possible role for BPI in clearance of cell-free endotoxin has also been suggested based on studies with purified endotoxin aggregates and blood monocytes. Because the interaction of BPI with cell-free endotoxin, during infection, occurs mainly in tissue and most likely in the form of shed bacterial outer membrane vesicles ("blebs"), we examined the effect of BPI on interactions of metabolically labeled ([(14)C]-acetate) blebs purified from Neisseria meningitidis serogroup B with either human monocyte-derived macrophages or monocyte-derived dendritic cells (MDDC). BPI produced a dose-dependent increase (up to 3-fold) in delivery of (14)C-labeled blebs to MDDC, but not to monocyte-derived macrophages in the presence or absence of serum. Both, fluorescently labeled blebs and BPI were internalized by MDDC under these conditions. The closely related LPS-binding protein, in contrast to BPI, did not increase association of the blebs with MDDC. BPI-enhanced delivery of the blebs to MDDC did not increase cell activation but permitted CD14-dependent signaling by the blebs as measured by changes in MDDC morphology, surface expression of CD80, CD83, CD86, and MHC class II and secretion of IL-8, RANTES, and IP-10. These findings suggest a novel role of BPI in the interaction of bacterial outer membrane vesicles with dendritic cells that may help link innate immune recognition of endotoxin to Ag delivery and presentation.

  6. Improvements in glucose metabolism early after gastric bypass surgery are not explained by increases in total bile acids and fibroblast growth factor 19 concentrations

    DEFF Research Database (Denmark)

    Jørgensen, Nils B; Dirksen, Carsten; Bojsen-Møller, Kirstine N


    Context: Bile acids and fibroblast growth factor 19 (FGF19) have been suggested as key mediators of the improvements in glucose metabolism after Roux-en-Y gastric bypass (RYGB). Objective: To describe fasting and postprandial state total bile acid (TBA) and FGF19 concentrations before and after...... (T2D) patients and 12 normal glucose tolerant (NGT) subjects participated in the study. Intervention: A 4-hour liquid meal test was performed before and 1 week, 3 months, and 1 year after RYGB. Main Outcome Measures: We measured fasting and postprandial TBA and FGF19 concentrations. Results: Fasting...... TBA concentrations decreased in NGT subjects (P

  7. Robotically-Assisted Coronary Artery Bypass Grafting

    Directory of Open Access Journals (Sweden)

    Thierry A. Folliguet


    Full Text Available Objectives. Robotic surgery enables to perform coronary surgery totally endoscopically. This report describes our experience using the da Vinci system for coronary artery bypass surgery. Methods. Patients requiring single-or-double vessel revascularization were eligible. The procedure was performed without cardiopulmonary bypass on a beating heart. Results. From April 2004 to May 2008, fifty-six patients were enrolled in the study. Twenty-four patients underwent robotic harvesting of the mammary conduit followed by minimal invasive direct coronary artery bypass (MIDCAB, and twenty-three patients had a totally endoscopic coronary artery bypass (TECAB grafting. Nine patients (16% were converted to open techniques. The mean total operating time for TECAB was 372±104 minutes and for MIDCAB was 220±69 minutes. Followup was complete for all patients up to one year. There was one hospital death following MIDCAB and two deaths at follow up. Forty-eight patients had an angiogram or CT scan revealing occlusion or anastomotic stenoses (>50% in 6 patients. Overall permeability was 92%. Conclusions. Robotic surgery can be performed with promising results.

  8. Increased intestinal permeability to macromolecules and endotoxemia in patients with chronic alcohol abuse in different stages of alcohol-induced liver disease

    DEFF Research Database (Denmark)

    Parlesak, Alexandr; Schäfer, C.; Schütz, Tanja


    and mild to more advanced stages of liver disease, and to measure the concentration of endotoxins in the plasma, as these compounds derive from the intestinal flora and are suspected to contribute to the development of alcoholic liver disease (ALD). METHODS: The permeability to polyethylene glycol Mr 400......BACKGROUND/AIMS: No information is yet available about the influence of alcohol abuse on the translocation of larger molecules (Mr>1200) through the intestinal mucosa in man. The present study aimed to determine the intestinal permeability to macromolecules in patients with chronic alcohol abuse...... with alcoholic liver disease (20/54, pintestinal barrier, which might enhance...

  9. Capacity analysis of a bypass of roundabouts (United States)

    Sedlačik, Ivan; Slabý, Petr


    The capacity of the roads network mainly depends on the capacity of its nodal points - intersections. A connecting branch or a bypass is a lane or lanes inserted between two adjacent branches of a roundabout, providing redirection of vehicles, that would otherwise burden a circular lane. A bypass effect to the capacity of roundabouts, but also other types of level intersections, is undeniable. A connecting branch increases the total capacity of an intersection that takes a part of vehicles performing a manoeuver of the first right turn completely out of an intersection area. Redirecting vehicles reduces delay times at intersections and reduces queues at the entrance to an intersection. Bypasses improve the quality of transport. Limiting for the capacity of bypasses is the point of disconnection from the entrance into the roundabout and the connection point into the exit from the roundabout. Central parts of the bypasses have minimal effects on the capacity. The length of a bypass has to match with the maximum length of a queue of waiting vehicles at a given intensity level. The article deals with analysis of the bypass capacity at the roundabouts.

  10. Transient and local increase in the permeability of the blood-brain barrier and the blood-retinal barrier by hyperthermia of magnetic nanoparticles in a rat model (United States)

    Tabatabaei Shafie, Seyed Nasrollah

    After successfully propelling therapeutic agents encapsulated in magnetic micro-carriers to a specific location inside an animal model by the gradient magnetic field of a modified clinical Magnetic Resonance (MR) scanner, we are now aiming to perform local drug delivery in the region of the central nervous system (CNS). To achieve localized drug delivery and increase efficacy, this project advances the theme that the therapeutic agents must be administered by means no more invasive than an intravenous injection followed by remote propulsion, controlled tracking, and on-command actuation in the CNS. The demanding function of the CNS requires an extremely stable environment. In fact, any small change in the composition of the interstitial fluid in the CNS plays a predominant role in regulating its microenvironment and neuronal activity. Therefore, the CNS is conceived to protect itself from frequent fluctuations of extracellular concentration of hormones, amino acids, and ion levels that occur after meals, exercise, or stress - as well as from toxic pathogens that may be circulating in the blood stream. This preventive barrier consists mainly of tightly interconnected endothelial cells that carpet the inner surface of most blood vessels in the CNS. While it provides a stable neuronal environment, more than 98% of all drug molecules are not able to cross this barrier and the extent to which a molecule enters is determined only by the permeability characteristics of the barrier. Therefore, while pharmaceutical research progresses for drug delivery to the CNS, it is limited by its pharmacokinetics through physiological barriers. Successful transient and local opening of the barrier for diffusion of therapeutics could strongly support the feasibility of treating a variety of neurological disorders. A recent effort presented in this dissertation provides evidence for the emergence of a novel approach to overcome this problem. This technique uses magnetic nanoparticles

  11. Yersinia pseudotuberculosis and Yersinia pestis show increased outer membrane permeability to hydrophobic agents which correlates with lipopolysaccharide acyl-chain fluidity. (United States)

    Bengoechea, J A; Brandenburg, K; Seydel, U; Díaz, R; Moriyón, I


    The hydrophobic probe N-phenyl-1-naphthylamine accumulated less in non-pathogenic Yersinia spp. and non-pathogenic and pathogenic Yersinia enterocolitica than in Yersinia pseudotuberculosis or Yersinia pestis. This was largely due to differences in the activity of efflux systems, but also to differences in outer membrane permeability because uptake of the probe in KCN/arsenate-poisoned cells was slower in the former group than in Y. pseudotuberculosis and Y. pestis. The probe accumulation rate was higher in Y. pseudotuberculosis and Y. pestis grown at 37 degrees C than at 26 degrees C and was always highest in Y. pestis. These yersiniae had LPSs with shorter polysaccharides than Y. enterocolitica, particularly when grown at 37 degrees C. Gelliquid-crystalline phase transitions (Tc 28-31 degrees C) were observed in LPS aggregates of Y. enterocolitica grown at 26 and 37 degrees C, with no differences between non-pathogenic and pathogenic strains. Y. pseudotuberculosis and Y. pestis LPSs showed no phase transitions and, although the fluidity of LPSs of Y. pseudotuberculosis and Y. enterocolitica grown at 26 degrees C were close below the Tc of the latter, they were always in a more fluid state than Y. enterocolitica LPS. Comparison with previous studies of Salmonella choleraesuis subsp. choleraesuis serotype minnesota rough LPS showed that the increased fluidity and absence of transition of Y. pseudotuberculosis and Y. pestis LPSs cannot be explained by their shorter polysaccharides and suggested differences at the lipid A/core level. It is proposed that differences in LPS-LPS interactions and efflux activity explain the above observations and reflect the adaptation of Yersinia spp. to different habitats.

  12. Permeability testing of biomaterial membranes

    Energy Technology Data Exchange (ETDEWEB)

    Dreesmann, L; Hajosch, R; Nuernberger, J Vaz; Schlosshauer, B [NMI Natural and Medical Sciences Institute at University Tuebingen, Markwiesenstr. 55, D-72770 Reutlingen (Germany); Ahlers, M [GELITA AG, Gammelsbacher Str. 2, D-69412 Eberbach (Germany)], E-mail:


    The permeability characteristics of biomaterials are critical parameters for a variety of implants. To analyse the permeability of membranes made from crosslinked ultrathin gelatin membranes and the transmigration of cells across the membranes, we combined three technical approaches: (1) a two-chamber-based permeability assay, (2) cell culturing with cytochemical analysis and (3) biochemical enzyme electrophoresis (zymography). Based on the diffusion of a coloured marker molecule in conjunction with photometric quantification, permeability data for a gelatin membrane were determined in the presence or absence of gelatin degrading fibroblasts. Cytochemical evaluation after cryosectioning of the membranes was used to ascertain whether fibroblasts had infiltrated the membrane inside. Zymography was used to investigate the potential release of proteases from fibroblasts, which are known to degrade collagen derivatives such as gelatin. Our data show that the diffusion equilibrium of a low molecular weight dye across the selected gelatin membrane is approached after about 6-8 h. Fibroblasts increase the permeability due to cavity formation in the membrane inside without penetrating the membrane for an extended time period (>21 days in vitro). Zymography indicates that cavity formation is most likely due to the secretion of matrix metalloproteinases. In summary, the combination of the depicted methods promises to facilitate a more rational development of biomaterials, because it provides a rapid means of determining permeability characteristics and bridges the gap between descriptive methodology and the mechanistic understanding of permeability alterations due to biological degradation.

  13. Increased intestinal permeability to (51 Cr) EDTA is correlated with IgA immune complex-plasma levels in children with IgA-associated nephropathies

    NARCIS (Netherlands)

    Davin, J. C.; Forget, P.; Mahieu, P. R.


    Intestinal permeability was investigated in 10 normal young adults, in 11 control children and in 9 children presenting with either Berger disease (4 cases) or Henoch-Schönlein nephritis (5 cases), making use of (51 Cr) EDTA as a probe molecule. All subjects exhibited a normal creatinine clearance

  14. Depleted energy charge and increased pulmonary endothelial permeability induced by mitochondrial complex I inhibition are mitigated by coenzyme Q1 in the isolated perfused rat lung. (United States)

    Bongard, Robert D; Yan, Ke; Hoffmann, Raymond G; Audi, Said H; Zhang, Xiao; Lindemer, Brian J; Townsley, Mary I; Merker, Marilyn P


    Mitochondrial dysfunction is associated with various forms of lung injury and disease that also involve alterations in pulmonary endothelial permeability, but the relationship, if any, between the two is not well understood. This question was addressed by perfusing isolated intact rat lung with a buffered physiological saline solution in the absence or presence of the mitochondrial complex I inhibitor rotenone (20 μM). Compared to control, rotenone depressed whole lung tissue ATP from 5.66 ± 0.46 (SEM) to 2.34 ± 0.15 µmol · g(-1) dry lung, with concomitant increases in the ADP:ATP and AMP:ATP ratios. Rotenone also increased lung perfusate lactate (from 12.36 ± 1.64 to 38.62 ± 3.14 µmol · 15 min(-1) perfusion · g(-1) dry lung) and the lactate:pyruvate ratio, but had no detectable impact on lung tissue GSH:GSSG redox status. The amphipathic quinone coenzyme Q1 (CoQ1; 50 μM) mitigated the impact of rotenone on the adenine nucleotide balance, wherein mitigation was blocked by NAD(P)H-quinone oxidoreductase 1 or mitochondrial complex III inhibitors. In separate studies, rotenone increased the pulmonary vascular endothelial filtration coefficient (Kf) from 0.043 ± 0.010 to 0.156 ± 0.037 ml · min(-1) · cm H2O(-1) · g(-1) dry lung, and CoQ1 protected against the effect of rotenone on Kf. A second complex I inhibitor, piericidin A, qualitatively reproduced the impact of rotenone on Kf and the lactate:pyruvate ratio. Taken together, the observations imply that pulmonary endothelial barrier integrity depends on mitochondrial bioenergetics as reflected in lung tissue ATP levels and that compensatory activation of whole lung glycolysis cannot protect against pulmonary endothelial hyperpermeability in response to mitochondrial blockade. The study further suggests that low-molecular-weight amphipathic quinones may have therapeutic utility in protecting lung barrier function in mitochondrial insufficiency. Published by Elsevier Inc.

  15. Depleted energy charge and increased pulmonary endothelial permeability induced by mitochondrial complex I inhibition are mitigated by coenzyme Q1 in the isolated perfused rat lung (United States)

    Bongard, Robert D.; Yan, Ke; Hoffmann, Raymond G.; Audi, Said H.; Zhang, Xiao; Lindemer, Brian J.; Townsley, Mary I.; Merker, Marilyn P.


    Mitochondrial dysfunction is associated with various forms of lung injury and disease that also involve alterations in pulmonary endothelial permeability, but the relationship, if any, between the two is not well understood. This question was addressed by perfusing the isolated intact rat lung with a buffered physiological saline solution in the absence or presence of the mitochondrial complex I inhibitor rotenone (20 uM). As compared to control, rotenone depressed whole lung tissue ATP from 5.66 ± 0.46 (SEM) to 2.34 ± 0.15 (SEM) μmol·gram−1 dry lung, with concomitant increases in the ADP:ATP and AMP:ATP ratios. Rotenone also increased lung perfusate lactate (from 12.36 ± 1.64 (SEM) to 38.62 ± 3.14 μmol·15 min−1 perfusion·gm−1 dry lung) and the lactate:pyruvate ratio, but had no detectable impact on lung tissue GSH:GSSG redox status. The amphipathic quinone, coenzyme Q1 (CoQ1; 50 μM) mitigated the impact of rotenone on the adenine nucleotide balance, wherein mitigation was blocked by NAD(P)H:quinone oxidoreductase 1 (NQO1) or mitochondrial complex III inhibitors. In separate studies, rotenone increased the pulmonary vascular endothelial filtration coefficient (Kf) from 0.043 ± 0.010 (SEM) to 0.156 ± 0.037 (SEM) ml·min−1·cm H2O−1·gm−1 dry lung weight, and CoQ1 protected against the effect of rotenone on Kf. A second complex I inhibitor, piericidin A, qualitatively reproduced the impact of rotenone on Kf and the lactate/pyruvate ratio. Taken together, the observations imply that pulmonary endothelial barrier integrity depends on mitochondrial bioenergetics as reflected in lung tissue ATP levels and that compensatory activation of whole lung glycolysis cannot protect against pulmonary endothelial hyperpermeability in response to mitochondrial blockade. The study further suggests that low molecular weight amphipathic quinones may have therapeutic utility in protecting lung barrier function in mitochondrial insufficiency. PMID:23912160

  16. In vivo confocal microscopy: increased conjunctival or episcleral leukocyte adhesion in patients who wear contact lenses with lower oxygen permeability (Dk) values. (United States)

    Nguyen, Thuy H; Dudek, Lara T; Krisciunas, Tammie C; Matiaco, Paul; Planck, Stephen R; Mathers, William D; Rosenbaum, James T


    Contact lens wear is known to threaten the health of the ocular surface. In vivo confocal microscopy (IVCM) to visualize leukocyte rolling and extravasation in inflammation was recently described. We tested the hypothesis that contact lens wear is associated with measurable inflammation in superficial vessels. Leukocyte rolling and sticking (hallmarks of the inflammatory process) were recorded by IVCM. IVCM was performed on conjunctival or episcleral blood vessels bilaterally on 55 contact lens wearers (15 male, 40 female) and 22 non-contact lens wearers (8 male, 14 female). Data were analyzed in 2 ways. Considering each vessel as an independent variable resulted in 132 analyzable vessel segments (13 daily disposable contact lenses, 67 traditional contact lenses, 14 rigid gas-permeable lenses, and 38 controls). Considering each subject as an independent variable resulted in analyzable data for 47 subjects (5 daily disposable contact lens wearers, 22 traditional contact lens wearers, 5 rigid contact lens wearers, and 15 control patients). Free-flowing, sticking, and rolling cells were counted in the vessels. Multiple parameters including mean flow velocity, shear rate, rolling cells/mm/min, and sticking cells/mm were calculated. We found no significant difference in leukocyte adhesion between control patients and patients wearing daily disposable, traditional disposable, or rigid gas-permeable lenses in both types of statistical analyses. However, the data regarding vessel segments as an independent variable show that there were more rolling cells in patients who wore contact lenses with oxygen permeability values (Dk) less than 10 as compared to those who wore contact lenses with oxygen permeability values greater than 16 (P oxygen permeability.

  17. Gut hormones and gastric bypass

    DEFF Research Database (Denmark)

    Holst, Jens J.


    Gut hormone secretion in response to nutrient ingestion appears to depend on membrane proteins expressed by the enteroendocrine cells. These include transporters (glucose and amino acid transporters), and, in this case, hormone secretion depends on metabolic and electrophysiological events elicited...... that determines hormone responses. It follows that operations that change intestinal exposure to and absorption of nutrients, such as gastric bypass operations, also change hormone secretion. This results in exaggerated increases in the secretion of particularly the distal small intestinal hormones, GLP-1, GLP-2......, oxyntomodulin, neurotensin and peptide YY (PYY). However, some proximal hormones also show changes probably reflecting that the distribution of these hormones is not restricted to the bypassed segments of the gut. Thus, cholecystokinin responses are increased, whereas gastric inhibitory polypeptide responses...

  18. Beneficial Effects of Anti-Interleukin-6 Antibodies on Impaired Gastrointestinal Motility, Inflammation and Increased Colonic Permeability in a Murine Model of Sepsis Are Most Pronounced When Administered in a Preventive Setup.

    Directory of Open Access Journals (Sweden)

    Sara Nullens

    Full Text Available During sepsis, gastrointestinal ileus, mucosal barrier dysfunction and bacterial translocation are accepted to be important triggers that can maintain or exacerbate the septic state. In the caecal ligation and puncture animal model of sepsis, we demonstrated that systemic and colonic interleukin-6 levels are significantly increased coinciding with an impaired colonic barrier function. We therefore aimed to study the effect of therapeutic or curative administration of anti-IL6 antibodies on overall GI motility, colonic permeability and translocation of intestinal bacteria in blood and mesenteric lymph nodes in the mouse caecal ligation and puncture model.OF-1 mice were randomized to either the preventive or curative protocol, in which they received 1 mg/kg of antibodies to interleukin-6, or its IgG isotype control solution. They subsequently underwent either the caecal ligation and puncture procedure, or sham-surgery. GI motility was assessed 48 h following the procedure, as well as colonic permeability, serum and colon cytokines, colonic tight junction proteins at the mRNA level; cultures of blood and mesenteric lymph nodes were performed.Preventive administration of anti-interleukin-6 antibodies successfully counteracted the gastrointestinal motility disturbances and impaired colonic barrier function that could be observed in vehicle-treated septic animals. Serum and colonic levels of proinflammatory cytokines were significantly lower when animals were preventively treated with anti-interleukin-6 antibodies. A repetitive injection 24 h later resulted in the most pronounced effects. Curative treatment significantly lowered systemic and colonic inflammation markers while the effects on transit and permeability were unfortunately no longer significant.Caecal ligation and puncture resulted in septic ileus with an increased colonic permeability. Antibodies to interleukin-6 were able to ameliorate gastro-intestinal motility, suppress inflammation and

  19. Arterial bypass leg - slideshow (United States)

    ... presentations/100155.htm Arterial bypass leg - series—Normal anatomy To use the sharing features on this page, ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  20. Thrombin During Cardiopulmonary Bypass

    National Research Council Canada - National Science Library

    Edmunds, L. Henry; Colman, Robert W


    Cardiopulmonary bypass (CPB) ignites a massive defense reaction that stimulates all blood cells and five plasma protein systems to produce a myriad of vasoactive and cytotoxic substances, cell-signaling molecules...

  1. Cardiopulmonary bypass in pregnancy

    National Research Council Canada - National Science Library

    Kapoor, MukulChandra


      Cardiac surgery carried out on cardiopulmonary bypass (CPB) in a pregnant woman is associated with poor neonatal outcomes although maternal outcomes are similar to cardiac surgery in non-pregnant women...

  2. Cardiopulmonary bypass and hemostasis

    NARCIS (Netherlands)

    Eijsman, Leon


    In chapter 1, we recalled that intracardiac defects can only be corrected when cardiopulmonary circulation is maintained by extracorporeal criculation and ventilation. To prevent clot formation in this artificial circuit, the socalled cardiopulmonary bypass (CPB), we completely depend on the

  3. Gastric bypass surgery - discharge (United States)

    ... heart disease Gastric bypass surgery Laparoscopic gastric banding Obesity Obstructive sleep apnea - adults Type 2 diabetes Patient Instructions Getting out of bed after surgery Weight-loss surgery - after - what to ask your doctor Weight- ...

  4. Bypassing damaged nervous tissue

    CERN Document Server

    Shneider, M N


    We show the principal ability of bypassing damaged demyelinated portions of nervous tissue, thereby restoring its normal function for the passage of action potentials. We carry out a theoretical analysis on the basis of the synchronization mechanism of action potential propagation along a bundle of neurons, proposed recently in [1]. And we discuss the feasibility of implement a bypass to restore damaged nervous tissue and creating an artificial neuron network.

  5. Extra-intracranial standard bypass in the elderly

    DEFF Research Database (Denmark)

    Sandow, Nora; von Weitzel-Mudersbach, Paul; Rosenbaum, Sverre


    Patients with chronic atherosclerotic vessel occlusion and cerebrovascular hemodynamic insufficiency may benefit from extra-intracranial (EC-IC) bypass surgery. Due to demographic changes, an increasing number of elderly patients presents with cerebrovascular hemodynamic insufficiency. So far......, little data for EC-IC bypass surgery in elderly patients suffering occlusive cerebrovascular disease are available. We therefore designed a retrospective study to address the question whether EC-IC bypass is a safe and efficient treatment in a patient cohort ≥70 years....

  6. Air permeability of polyester nonwoven fabrics

    Directory of Open Access Journals (Sweden)

    Zhu Guocheng


    Full Text Available Air permeability is one of the most important properties of non-woven fabrics in many applications. This paper aims to investigate the effects of thickness, porosity and density on the air permeability of needle-punched non-woven fabrics and compare the experimental values with two models which are based on hydraulic radius theory and drag theory, respectively. The air permeability of the samples was measured by an air permeability tester FX3300. The results showed that the air permeability of non-woven fabrics decreased with the increase in thickness and density of samples, increased with the increase of porosity, and the air permeability was not directly proportional to the pressure gradient. Meanwhile, the prediction model based on hydraulic radius theory had a better agreement with experimental values than the model based on drag theory, but the values were much higher than the experimental results, especially for higher porosity and higher pressure gradient.

  7. Darcy permeability of hollow fiber membrane bundles made from Membrana® Polymethylpentene (PMP) fibers used in respiratory assist devices (United States)

    Madhani, Shalv. P.; D’Aloiso, Brandon. D.; Frankowski, Brian.; Federspiel, William. J.


    Hollow fiber membranes (HFMs) are used in blood oxygenators for cardiopulmonary bypass or in next generation artificial lungs. Flow analyses of these devices is typically done using computational fluid dynamics (CFD) modeling HFM bundles as porous media, using a Darcy permeability coefficient estimated from the Blake – Kozeny (BK) equation to account for viscous drag from fibers. We recently published how well this approach can predict Darcy permeability for fiber bundles made from polypropylene HFMs, showing the prediction can be significantly improved using an experimentally derived correlation between the BK constant (A) and bundle porosity (ε). In this study, we assessed how well our correlation for A worked for predicting the Darcy permeability of fiber bundles made from Membrana® polymethylpentene (PMP) HFMs, which are increasingly being used clinically. Swatches in the porosity range of 0.4 to 0.8 were assessed in which sheets of fiber were stacked in parallel, perpendicular and angled configurations. Our previously published correlation predicted Darcy within ±8%. A new correlation based on current and past measured permeability was determined: A=497ε-103; using this correlation measured Darcy permeability was within ±6%. This correlation varied from 8% to −3.5% of our prior correlation over the tested porosity range. PMID:26809086

  8. Darcy Permeability of Hollow Fiber Membrane Bundles Made from Membrana Polymethylpentene Fibers Used in Respiratory Assist Devices. (United States)

    Madhani, Shalv P; D'Aloiso, Brandon D; Frankowski, Brian; Federspiel, William J


    Hollow fiber membranes (HFMs) are used in blood oxygenators for cardiopulmonary bypass or in next generation artificial lungs. Flow analyses of these devices is typically done using computational fluid dynamics (CFD) modeling HFM bundles as porous media, using a Darcy permeability coefficient estimated from the Blake-Kozeny (BK) equation to account for viscous drag from fibers. We recently published how well this approach can predict Darcy permeability for fiber bundles made from polypropylene HFMs, showing the prediction can be significantly improved using an experimentally derived correlation between the BK constant (A) and bundle porosity (ε). In this study, we assessed how well our correlation for A worked for predicting the Darcy permeability of fiber bundles made from Membrana polymethylpentene (PMP) HFMs, which are increasingly being used clinically. Swatches in the porosity range of 0.4 to 0.8 were assessed in which sheets of fiber were stacked in parallel, perpendicular, and angled configurations. Our previously published correlation predicted Darcy within ±8%. A new correlation based on current and past measured permeability was determined: A = 497ε - 103; using this correlation measured Darcy permeability was within ±6%. This correlation varied from 8% to -3.5% of our prior correlation over the tested porosity range.

  9. The Role of miR-330-3p/PKC-α Signaling Pathway in Low-Dose Endothelial-Monocyte Activating Polypeptide-II Increasing the Permeability of Blood-Tumor Barrier

    Directory of Open Access Journals (Sweden)

    Jiahui Liu


    Full Text Available This study was performed to determine whether EMAP II increases the permeability of the blood-tumor barrier (BTB by affecting the expression of miR-330-3p as well as its possible mechanisms. We determined the over-expression of miR-330-3p in glioma microvascular endothelial cells (GECs by Real-time PCR. Endothelial monocyte-activating polypeptide-II (EMAP-II significantly decreased the expression of miR-330-3p in GECs. Pre-miR-330-3p markedly decreased the permeability of BTB and increased the expression of tight junction (TJ related proteins ZO-1, occludin and claudin-5, however, anti-miR-330-3p had the opposite effects. Anti-miR-330-3p could enhance the effect of EMAP-II on increasing the permeability of BTB, however, pre-miR-330-3p partly reversed the effect of EMAP-II on that. Similarly, anti-miR-330-3p improved the effects of EMAP-II on increasing the expression levels of PKC-α and p-PKC-α in GECs and pre-miR-330-3p partly reversed the effects. MiR-330-3p could target bind to the 3′UTR of PKC-α. The results of in vivo experiments were similar to those of in vitro experiments. These suggested that EMAP-II could increase the permeability of BTB through inhibiting miR-330-3p which target negative regulation of PKC-α. Pre-miR-330-3p and PKC-α inhibitor decreased the BTB permeability and up-regulated the expression levels of ZO-1, occludin and claudin-5 while anti-miR-330-3p and PKC-α activator brought the reverse effects. Compared with EMAP-II, anti-miR-330-3p and PKC-α activator alone, the combination of the three combinations significantly increased the BTB permeability. EMAP-II combined with anti-miR-330-3p and PKCα activator could enhance the DOX’s effects on inhibiting the cell viabilities and increasing the apoptosis of U87 glioma cells. Our studies suggest that low-dose EMAP-II up-regulates the expression of PKC-α and increases the activity of PKC-α by inhibiting the expression of miR-330-3p, reduces the expression of ZO-1

  10. Permeability prediction in chalks

    DEFF Research Database (Denmark)

    Alam, Mohammad Monzurul; Fabricius, Ida Lykke; Prasad, Manika


    prediction, so we have investigated the use of velocity data to predict permeability. The compressional velocity fromwireline logs and core plugs of the chalk reservoir in the South Arne field, North Sea, has been used for this study. We compared various methods of permeability prediction from velocities......-permeability relationships were replaced by relationships between velocity of elastic waves and permeability using laboratory data, and the relationships were then applied to well-log data. We found that the permeability prediction in chalk and possibly other sediments with large surface areas could be improved...

  11. A Time Interval of More Than 18 Months Between a Pregnancy and a Roux-en-Y Gastric Bypass Increases the Risk of Iron Deficiency and Anaemia in Pregnancy. (United States)

    Crusell, Mie; Nilas, Lisbeth; Svare, Jens; Lauenborg, Jeannet


    The aim of the study is to explore the impact of time between Roux-en-Y gastric bypass (RYGB) and pregnancy on obstetrical outcome and nutritional derangements. In a retrospective cross-sectional study of pregnant women admitted for antenatal care at two tertiary hospitals, we examined 153 women with RYGB and a singleton pregnancy of at least 24 weeks. The women were stratified according to a pregnancy nutritional parameters and glycated haemoglobin 1Ac (HbA1c) in second and third trimester of pregnancy, gestational hypertension, length of pregnancy, mode of delivery and foetal birth weight. The two groups were comparable regarding age, parity and prepregnancy body mass index. The frequency of iron deficiency anaemia (ferritin anaemia but not of other nutritional deficits. Time interval does not seem to have an adverse effect on the obstetrical outcome, including intrauterine growth restriction. Specific attention is needed on iron deficit with increasing surgery-to-pregnancy time interval.

  12. Film Permeability Determination Using Static Permeability Cells (United States)

    The permeability of tarps to soil fumigant pesticides varies depending on the active ingredient chemical: dimethyl disulfide (DMDS), methyl bromide, chloropicrin, or other. The diffusion rate can be represented by the mass transfer coefficient (MTC).

  13. Estimation of soil permeability

    Directory of Open Access Journals (Sweden)

    Amr F. Elhakim


    Full Text Available Soils are permeable materials because of the existence of interconnected voids that allow the flow of fluids when a difference in energy head exists. A good knowledge of soil permeability is needed for estimating the quantity of seepage under dams and dewatering to facilitate underground construction. Soil permeability, also termed hydraulic conductivity, is measured using several methods that include constant and falling head laboratory tests on intact or reconstituted specimens. Alternatively, permeability may be measured in the field using insitu borehole permeability testing (e.g. [2], and field pumping tests. A less attractive method is to empirically deduce the coefficient of permeability from the results of simple laboratory tests such as the grain size distribution. Otherwise, soil permeability has been assessed from the cone/piezocone penetration tests (e.g. [13,14]. In this paper, the coefficient of permeability was measured using field falling head at different depths. Furthermore, the field coefficient of permeability was measured using pumping tests at the same site. The measured permeability values are compared to the values empirically deduced from the cone penetration test for the same location. Likewise, the coefficients of permeability are empirically obtained using correlations based on the index soil properties of the tested sand for comparison with the measured values.

  14. Clogging in permeable concrete: A review. (United States)

    Kia, Alalea; Wong, Hong S; Cheeseman, Christopher R


    Permeable concrete (or "pervious concrete" in North America) is used to reduce local flooding in urban areas and is an important sustainable urban drainage system. However, permeable concrete exhibits reduction in permeability due to clogging by particulates, which severely limits service life. This paper reviews the clogging mechanism and current mitigating strategies in order to inform future research needs. The pore structure of permeable concrete and characteristics of flowing particulates influence clogging, which occurs when particles build-up and block connected porosity. Permeable concrete requires regular maintenance by vacuum sweeping and pressure washing, but the effectiveness and viability of these methods is questionable. The potential for clogging is related to the tortuosity of the connected porosity, with greater tortuosity resulting in increased potential for clogging. Research is required to develop permeable concrete that can be poured on-site, which produces a pore structure with significantly reduced tortuosity. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Rural Bypass for Elective Surgeries. (United States)

    Weigel, Paula A M; Ullrich, Fred; Finegan, Chance N; Ward, Marcia M


    Rural bypass of Critical Access Hospitals (CAHs) for elective inpatient and outpatient surgical procedures has not been studied. Residents choosing to have their elective surgeries elsewhere, when the local CAH provides those surgical services, erode their rural hospital's financial base. The purpose of this research is to describe the elective surgical bypass rate, the procedures most commonly bypassed by rural residents, the distribution of volume among CAHs that offer elective surgical services, and factors predictive of bypass. A sample of elective surgery discharges was created from the 2011 Healthcare Cost and Utilization Project State Inpatient Databases and State Ambulatory Surgery Databases for Colorado, North Carolina, Vermont, and Wisconsin. Frequencies of procedures bypassed and CAH volume distribution were performed. Logistic regression was used to model factors associated with rural bypass for elective surgical care. The rural bypass rate for elective surgical procedures is 48.4%. Procedures bypassed most are operations on the musculoskeletal system, eye, and digestive system. Annual volume distribution for elective surgical procedures among CAHs varied widely. Patients who are younger, medically complex, at higher surgical risk, and have private insurance are at higher odds of bypass. Patients are also more likely to bypass low-volume hospitals. Rural hospitals should consider developing surgical services that are performed electively and on an outpatient basis that are attractive to a broader rural population. CAHs that already offer elective surgical procedures and yet who are still bypassed must examine the mutable factors that drive bypass behavior. © 2015 National Rural Health Association.

  16. The Best Bypass Surgery Trial

    DEFF Research Database (Denmark)

    Møller, Christian H; Jensen, Birte Østergaard; Gluud, Christian


    Recent trials suggest that off-pump coronary artery bypass grafting (OPCAB) reduces the risk of mortality and morbidity compared with conventional coronary artery bypass grafting (CCAB) using cardiopulmonary bypass. Patients with a moderate- to high-risk of complications after CCAB may have...

  17. Bentonite Permeability at Elevated Temperature

    Directory of Open Access Journals (Sweden)

    Katherine A. Daniels


    Full Text Available Repository designs frequently favour geological disposal of radioactive waste with a backfill material occupying void space around the waste. The backfill material must tolerate the high temperatures produced by decaying radioactive waste to prevent its failure or degradation, leading to increased hydraulic conductivity and reduced sealing performance. The results of four experiments investigating the effect of temperature on the permeability of a bentonite backfill are presented. Bentonite is a clay commonly proposed as the backfill in repository designs because of its high swelling capacity and very low permeability. The experiments were conducted in two sets of purpose-built, temperature controlled apparatus, designed to simulate isotropic pressure and constant volume conditions within the testing range of 4–6 MPa average effective stress. The response of bentonite during thermal loading at temperatures up to 200 °C was investigated, extending the previously considered temperature range. The results provide details of bentonite’s intrinsic permeability, total stress, swelling pressure and porewater pressure during thermal cycles. We find that bentonite’s hydraulic properties are sensitive to thermal loading and the type of imposed boundary condition. However, the permeability change is not large and can mostly be accounted for by water viscosity changes. Thus, under 150 °C, temperature has a minimal impact on bentonite’s hydraulic permeability.

  18. Vascular permeability in cerebral cavernous malformations. (United States)

    Mikati, Abdul G; Khanna, Omaditya; Zhang, Lingjiao; Girard, Romuald; Shenkar, Robert; Guo, Xiaodong; Shah, Akash; Larsson, Henrik B W; Tan, Huan; Li, Luying; Wishnoff, Matthew S; Shi, Changbin; Christoforidis, Gregory A; Awad, Issam A


    Patients with the familial form of cerebral cavernous malformations (CCMs) are haploinsufficient for the CCM1, CCM2, or CCM3 gene. Loss of corresponding CCM proteins increases RhoA kinase-mediated endothelial permeability in vitro, and in mouse brains in vivo. A prospective case-controlled observational study investigated whether the brains of human subjects with familial CCM show vascular hyperpermeability by dynamic contrast-enhanced quantitative perfusion magnetic resonance imaging, in comparison with CCM cases without familial disease, and whether lesional or brain vascular permeability correlates with CCM disease activity. Permeability in white matter far (WMF) from lesions was significantly greater in familial than in sporadic cases, but was similar in CCM lesions. Permeability in WMF increased with age in sporadic patients, but not in familial cases. Patients with more aggressive familial CCM disease had greater WMF permeability compared to those with milder disease phenotype, but similar lesion permeability. Subjects receiving statin medications for routine cardiovascular indications had a trend of lower WMF, but not lesion, permeability. This is the first demonstration of brain vascular hyperpermeability in humans with an autosomal dominant disease, as predicted mechanistically. Brain permeability, more than lesion permeability, may serve as a biomarker of CCM disease activity, and help calibrate potential drug therapy.

  19. Vascular permeability in cerebral cavernous malformations (United States)

    Mikati, Abdul G; Khanna, Omaditya; Zhang, Lingjiao; Girard, Romuald; Shenkar, Robert; Guo, Xiaodong; Shah, Akash; Larsson, Henrik BW; Tan, Huan; Li, Luying; Wishnoff, Matthew S; Shi, Changbin; Christoforidis, Gregory A; Awad, Issam A


    Patients with the familial form of cerebral cavernous malformations (CCMs) are haploinsufficient for the CCM1, CCM2, or CCM3 gene. Loss of corresponding CCM proteins increases RhoA kinase-mediated endothelial permeability in vitro, and in mouse brains in vivo. A prospective case-controlled observational study investigated whether the brains of human subjects with familial CCM show vascular hyperpermeability by dynamic contrast-enhanced quantitative perfusion magnetic resonance imaging, in comparison with CCM cases without familial disease, and whether lesional or brain vascular permeability correlates with CCM disease activity. Permeability in white matter far (WMF) from lesions was significantly greater in familial than in sporadic cases, but was similar in CCM lesions. Permeability in WMF increased with age in sporadic patients, but not in familial cases. Patients with more aggressive familial CCM disease had greater WMF permeability compared to those with milder disease phenotype, but similar lesion permeability. Subjects receiving statin medications for routine cardiovascular indications had a trend of lower WMF, but not lesion, permeability. This is the first demonstration of brain vascular hyperpermeability in humans with an autosomal dominant disease, as predicted mechanistically. Brain permeability, more than lesion permeability, may serve as a biomarker of CCM disease activity, and help calibrate potential drug therapy. PMID:25966944

  20. Coronary Artery Bypass in Octogenarians

    Directory of Open Access Journals (Sweden)

    Chen-Yen Chien


    Full Text Available Prevalence of coronary artery disease (CAD has increased with the expansion of life span among the elderly population in the world. Hence, the issue of the coronary artery bypass in octogenarians has attracted more attention. Recent literature about the topic revealed nearly the same excellent results as those in the younger population under the newly developed operative techniques and improving concept in perioperative management and postoperative care. In this article, we review the current status of the procedure that was thought to be dangerous in the earlier era, including its risk factors, result, and benefit.

  1. Lower leg electrical impedance after distal bypass surgery

    DEFF Research Database (Denmark)

    Belanger, G K; Bolbjerg, M L; Heegaard, N H


    Electrical impedance was determined in 13 patients following distal bypass surgery to evaluate lower leg oedema as reflected by its circumference. Tissue injury was assessed by the plasma concentration of muscle enzymes. After surgery, the volume of the control lower leg increased from 1250 (816...... to be a useful method for the evaluation of lower leg oedema after distal bypass surgery....

  2. Computed tomography perfusion evaluation after extracranial-intracranial bypass surgery

    NARCIS (Netherlands)

    Vos, Pieter C.; Riordan, Alan J.; Smit, Ewoud J.; de Jong, Hugo W. A. M.; van der Zwan, Albert; Velthuis, BK; Viergever, Max A.; Dankbaar, Jan Willem

    Objective: Perfusion imaging is increasingly used for postoperative evaluation of extracranial to intracranial (EC-IC) bypass surgery. Altered hemodynamics and delayed arrival of the contrast agent in the area fed by the bypass can influence perfusion measurement. We compared perfusion asymmetry

  3. Aortic valve bypass

    DEFF Research Database (Denmark)

    Lund, Jens T; Jensen, Maiken Brit; Arendrup, Henrik


    In aortic valve bypass (AVB) a valve-containing conduit is connecting the apex of the left ventricle to the descending aorta. Candidates are patients with symptomatic aortic valve stenosis rejected for conventional aortic valve replacement (AVR) or transcatheter aortic valve implantation (TAVI...

  4. Artery Bypass Grafting

    African Journals Online (AJOL)


    nary artery disease (CAD) was coronary artery bypass graft (CAB G) using a segment of saphenous vein interposed between the ascend- ing aorta and the coronary artery distal to the obstructing lesion. This was performed by David Sabiston of Duke University in 1962. With the use of the recently developed technique of ...

  5. Alterations in Intestinal Permeability After Thermal Injury, (United States)


    Permeability After Burns-LeVoyer et al R wthe Arrihtv.of Su~gy8 4• u’y 1992, Voue 127 Copright 1992. Akn • Med/kaf Awoctahbn Patlenbs Controls 4. (n-=1...may have a role in the tinal tract is enteral nutrition . I was wondering if by any chance development of increased permeability, then we can evaluate

  6. Gas and Water Permeability of Concrete

    Energy Technology Data Exchange (ETDEWEB)

    Villar, M. V.; Martin, P. L.; Romero, F. J.; Gutierrez-Rodirgo, V.; Barcala, J. M.


    The gas pressure of concrete samples was measured in an unsteady-state equipment working under low injection pressures and in a newly fine tuned steady-state setup working under different pressures. These measurements allowed the estimation of the intrinsic and relative gas permeability of the concrete and of the effect of boundary conditions on them. Permeability decreased with water content, but it was also greatly affected by the hydraulic history of concrete, i.e. if it had been previously dried or wetted. In particular, and for a given degree of saturation, the gas permeability of concrete previously saturated was lower than if the concrete had been just air dried or saturated after air drying. In any case, the gas permeability was about two orders of magnitude higher than the liquid water permeability (10-16 vs. 10-18 m2), probably due to the chemical reactions taking place during saturation (carbonation). The relative gas permeability of concrete increased sharply for water degrees of saturation smaller than 50%. The boundary conditions also affected the gas permeability, which seemed to be mostly conditioned by the back pressure and the confining pressure, increasing as the former increased and decreasing as the latter increased, i.e. decreasing as the effective pressure increased. Overall the increase of pressure head or injection pressure implied a decrease in gas permeability. External,microcracking during air-drying could not be ruled out as responsible for the decrease of permeability with confining pressure. The apparent permeability obtained applying the Klinkenberg method for a given effective pressure was only slightly smaller than the average of all the values measured for the same confining pressure range. For this reason it is considered that the Klinkenberg effect was not relevant in the range of pressures applied. (Author) 37 refs.

  7. Pressure sensitivity of low permeability sandstones (United States)

    Kilmer, N.H.; Morrow, N.R.; Pitman, J.K.


    Detailed core analysis has been carried out on 32 tight sandstones with permeabilities ranging over four orders of magnitude (0.0002 to 4.8 mD at 5000 psi confining pressure). Relationships between gas permeability and net confining pressure were measured for cycles of loading and unloading. For some samples, permeabilities were measured both along and across bedding planes. Large variations in stress sensitivity of permeability were observed from one sample to another. The ratio of permeability at a nominal confining pressure of 500 psi to that at 5000 psi was used to define a stress sensitivity ratio. For a given sample, confining pressure vs permeability followed a linear log-log relationship, the slope of which provided an index of pressure sensitivity. This index, as obtained for first unloading data, was used in testing relationships between stress sensitivity and other measured rock properties. Pressure sensitivity tended to increase with increase in carbonate content and depth, and with decrease in porosity, permeability and sodium feldspar. However, scatter in these relationships increased as permeability decreased. Tests for correlations between pressure sensitivity and various linear combinations of variables are reported. Details of pore structure related to diagenetic changes appears to be of much greater significance to pressure sensitivity than mineral composition. ?? 1987.

  8. The permeability of oral leukoplakia. (United States)

    Bánóczy, Jolán; Squier, Christopher A; Kremer, Mary; Wertz, Philip W; Kövesi, György; Szende, Béla; Dombi, Csaba


    The significant increase in oral cancer mortality necessitates further research on the mechanisms of tumorigenesis. It was the aim of this study to compare the permeability, lipid composition and histopathological characteristics of oral leukoplakia with non-lesional specimens of the same region in 30 cases as well as 11 specimens originating from healthy control buccal mucosa. The permeability (Kp) of tissue biopsies to tritiated nitrosonornicotine was determined in a continuous through-flow perfusion system, lipids were extracted and identified by thin-layer chromatography, and thickness of epithelium and keratin layer assessed by histopathological methods. Results of the measurements showed that the permeability to the tobacco carcinogen, nitrosonornicotine for leukoplakic tissue was higher than for normal control buccal specimens. Non-lesional areas of buccal mucosa, adjacent to leukoplakias, showed hyperplasia and significantly higher permeability values than both leukoplakic and normal buccal control mucosa. The lipid content of the non-lesional sites was intermediate between the increased values of the leukoplakic lesion and of normal control mucosa. The data strongly suggest that the presence of tobacco in the oral cavity may bring about generalized changes even in regions that do not show leukoplakia.

  9. A Survey of Cache Bypassing Techniques

    Directory of Open Access Journals (Sweden)

    Sparsh Mittal


    Full Text Available With increasing core-count, the cache demand of modern processors has also increased. However, due to strict area/power budgets and presence of poor data-locality workloads, blindly scaling cache capacity is both infeasible and ineffective. Cache bypassing is a promising technique to increase effective cache capacity without incurring power/area costs of a larger sized cache. However, injudicious use of cache bypassing can lead to bandwidth congestion and increased miss-rate and hence, intelligent techniques are required to harness its full potential. This paper presents a survey of cache bypassing techniques for CPUs, GPUs and CPU-GPU heterogeneous systems, and for caches designed with SRAM, non-volatile memory (NVM and die-stacked DRAM. By classifying the techniques based on key parameters, it underscores their differences and similarities. We hope that this paper will provide insights into cache bypassing techniques and associated tradeoffs and will be useful for computer architects, system designers and other researchers.

  10. Bypass: A Memoir


    Amato, Joseph A.


    This inquiry into matters of heart, conducted under the shadows of pending surgery, awakens themes of boyhood, education, and marriage and prompt questions about loyalty to a deceased father, connections with immigrant grandparents, loss and rediscovery of faith, and solitude versus community. A medical narrative, the book also chronicles a span of contemporary American life. Throughout Amato's account, the consistent reminder of his upcoming bypass invites readers to reflect on their own liv...

  11. Relationship of femorodistal bypass patency to clinical outcome. Iloprost Bypass International Study Group

    DEFF Research Database (Denmark)

    Watson, H R; Schroeder, T V; Simms, M H


    To investigate the relationship between bypass patency, limb survival and clinical symptoms after femorodistal bypass procedures.......To investigate the relationship between bypass patency, limb survival and clinical symptoms after femorodistal bypass procedures....

  12. Vascular permeability in cerebral cavernous malformations

    DEFF Research Database (Denmark)

    Mikati, Abdul G; Khanna, Omaditya; Zhang, Lingjiao


    -controlled observational study investigated whether the brains of human subjects with familial CCM show vascular hyperpermeability by dynamic contrast-enhanced quantitative perfusion magnetic resonance imaging, in comparison with CCM cases without familial disease, and whether lesional or brain vascular permeability...... vascular hyperpermeability in humans with an autosomal dominant disease, as predicted mechanistically. Brain permeability, more than lesion permeability, may serve as a biomarker of CCM disease activity, and help calibrate potential drug therapy....... correlates with CCM disease activity. Permeability in white matter far (WMF) from lesions was significantly greater in familial than in sporadic cases, but was similar in CCM lesions. Permeability in WMF increased with age in sporadic patients, but not in familial cases. Patients with more aggressive...

  13. Early enhancements of hepatic and later of peripheral insulin sensitivity combined with increased postprandial insulin secretion contribute to improved glycemic control after Roux-en-Y gastric bypass

    DEFF Research Database (Denmark)

    Bojsen-Møller, Kirstine N; Dirksen, Carsten; Jørgensen, Nils Bruun


    after RYGB. Participants were included after a preoperative diet induced total weight loss of -9.2±1.2%. Hepatic and peripheral insulin sensitivity were assessed using the hyperinsulinemic euglycemic clamp combined with glucose tracer technique and beta-cell function evaluated in response...... to an intravenous glucose-glucagon challenge as well as an oral glucose load. Already within 1 week, RYGB reduced basal glucose production, improved basal hepatic insulin sensitivity and increased insulin clearance highlighting the liver as an important organ responsible for the early effects on glucose metabolism...... in response to oral glucose, underscoring the importance of the changed gut anatomy....

  14. Altered expression of micro-RNA 199a and increased levels of cardiac SIRT1 protein are associated with the occurrence of atrial fibrillation after coronary artery bypass graft surgery. (United States)

    Yamac, Aylin Hatice; Kucukbuzcu, Sitki; Ozansoy, Mehmet; Gok, Ozlem; Oz, Kursat; Erturk, Mehmet; Yilmaz, Emre; Ersoy, Burak; Zeybek, Rahmi; Goktekin, Omer; Kilic, Ulkan


    Postoperative atrial fibrillation (POAF) is a potentially life-threatening complication after coronary artery bypass graft (CABG) surgery. The expression of the cardioprotective SIRT1 protein with its antioxidant activity is increased in cardiac tissue of patients suffering from POAF. So far, information is lacking about the relationship between SIRT1 regulating micro RNAs (miRs), SIRT1 protein and the occurrence of POAF. A total of 63 patients undergoing CABG were recruited, and biopsies were obtained from the right atrial appendage during cannulation. Postoperative, all patients were rhythm-monitored until discharge and randomized to POAF (n=20) or sinus rhythm (n=43). The expression of the micro RNAs miR-199a and miR-195 was quantified by real-time PCR. SIRT1 protein was detected by western blot analysis. The relative expression of miR-199a in the POAF group was significantly decreased compared to the control group (0.77±0.27 vs. 1.11±0.69, P=.022) Accordingly, SIRT 1 protein was significantly induced in tissue probes of patients with POAF (P<.001). Altered expression of the SIRT1 protein regulating miR-199a in human atrial tissue was found to be related to the occurrence of POAF, indicating its usefulness as a biomarker for cardiac surgery management. Copyright © 2016 Elsevier Inc. All rights reserved.

  15. Roux-en-Y gastric bypass alleviates hypertension and is associated with an increase in mid-regional pro-atrial natriuretic peptide in morbid obese patients

    DEFF Research Database (Denmark)

    Bonfils, Peter K; Taskiran, Mustafa; Damgaard, Morten


    in plasma concentrations of atrial natriuretic peptide. METHODS: Twelve hypertensive and 12 normotensive morbidly obese patients underwent LRYGB: 24BP, systemic haemodynamics and mid-regional pro-atrial natriuretic peptide (MRproANP) were assessed before, 6 weeks and 12 months after surgery. The effect....... However, antihypertensive medications were successively reduced from baseline to 1 year after surgery. In normotensive patients, there was no change in 24BP 6 weeks after LRYGB, but a tendency towards a reduction 1 year after the operation. Plasma concentrations of MRproANP were subnormal prior to surgery...... nor after LRYGB. CONCLUSIONS: LRYGB resulted in a significant 24BP reduction and a substantial increase in MRproANP plasma concentrations in hypertensive, obese patients 6 weeks after surgery, suggesting a causal link between obesity-hypertension and altered release/degradation of cardiac natriuretic...


    Energy Technology Data Exchange (ETDEWEB)

    Olson, Aaron; Bouchard, Bertrand; Ning, Xue-Han; Isern, Nancy G.; Des Rosiers, Christine; Portman, Michael A.


    We utilized a translational model of infant CPB to test the hypothesis that T3 modulates pyruvate entry into the citric acid cycle (CAC) thereby providing the energy support for improved cardiac function after ischemia-reperfusion. Methods and Results: Neonatal piglets received intracoronary [2-13Carbon(13C)]-pyruvate for 40 minutes (8 mM) during control aerobic conditions (Cont) or immediately after reperfusion (IR) from global hypothermic ischemia. A third group (IR-Tr) received T3 (1.2 ug/kg) during reperfusion. We assessed absolute CAC intermediate levels (aCAC) and flux parameters into the CAC through oxidative pyruvate decarboxylation (PDC ) and anaplerotic carboxylation (PC; ) using 13C-labeled pyruvate and isotopomer analysis by gas and liquid chromatography-mass spectrometry and 13C NMR. Neither IR nor IR-Tr modified aCAC. However, compared to IR, T3 (group IR-Tr) increased cardiac power and oxygen consumption after CPB while elevating both PDC and PC (~ four-fold). T3 inhibited IR induced reductions in CAC intermediate molar percent enrichment (MPE) and oxaloacetate(citrate)/malate MPE ratio; an index of aspartate entry into the CAC. Conclusions: T3 markedly enhances PC and PDC thereby providing substrate for elevated cardiac function and work after reperfusion. The increases in pyruvate flux occur with preservation of the CAC intermediate pool. Additionally, T3 inhibition of reductions in CAC intermediate MPEs indicates that T3 reduces the reliance on amino acids (AA) for anaplerosis after reperfusion. Thus, AA should be more available for other functions such as protein synthesis.

  17. Rectal epithelial cell mitosis and expression of macrophage migration inhibitory factor are increased 3 years after Roux-en-Y gastric bypass (RYGB) for morbid obesity: implications for long-term neoplastic risk following RYGB. (United States)

    Kant, Prashant; Sainsbury, Anita; Reed, Karen R; Pollard, Stephen G; Scott, Nigel; Clarke, Alan R; Coletta, P Louise; Hull, Mark A


    Rectal epithelial cell mitosis and crypt size, as well as expression of proinflammatory genes including macrophage migration inhibitory factor (MIF), are increased 6 months after Roux-en-Y gastric bypass (RYGB) in morbidly obese patients. Tests were carried out to determine whether these putative colorectal cancer risk biomarkers remained elevated long term after RYGB, and the mechanistic basis, as well as the functional consequences, of Mif upregulation in intestinal epithelial cells was investigated. Rectal mucosa and blood were obtained a median of 3 years after RYGB from the original cohort of patients with RYGB (n = 19) for crypt microdissection, real-time PCR, immunohistochemistry for MIF and immunoassay of proinflammatory markers. Immunohistochemistry for Mif and bromodeoxyuridine labelling were performed on AhCre⁺ mouse and Apc(Min/⁺) mouse (with and without functional Mif alleles) intestine, respectively. Rectal epithelial cell mitosis and crypt size remained elevated 3 years after RYGB compared with preoperative values (1.7- and 1.5-fold, respectively; p < 0.05). There was a 40-fold (95% CI 13 to 125) increase in mucosal MIF transcript levels at 3 years associated with increased epithelial cell MIF protein levels. Conditional Apc loss in AhCre⁺ mice led to increased epithelial cell Mif content. Mif deficiency in Apc(Min/⁺) mice was associated with a combined defect in intestinal epithelial cell proliferation and migration, which was reflected by the longitudinal clinical data. Mucosal abnormalities persist 3 years after RYGB and include elevation of the protumorigenic cytokine MIF, which is upregulated following Apc loss and which contributes to intestinal epithelial cell homeostasis. These observations should prompt clinical studies of colorectal neoplastic risk after RYGB.

  18. Coronary Artery-Bypass-Graft Surgery Increases the Plasma Concentration of Exosomes Carrying a Cargo of Cardiac MicroRNAs: An Example of Exosome Trafficking Out of the Human Heart with Potential for Cardiac Biomarker Discovery.

    Directory of Open Access Journals (Sweden)

    Costanza Emanueli

    Full Text Available Exosome nanoparticles carry a composite cargo, including microRNAs (miRs. Cultured cardiovascular cells release miR-containing exosomes. The exosomal trafficking of miRNAs from the heart is largely unexplored. Working on clinical samples from coronary-artery by-pass graft (CABG surgery, we investigated if: 1 exosomes containing cardiac miRs and hence putatively released by cardiac cells increase in the circulation after surgery; 2 circulating exosomes and exosomal cardiac miRs correlate with cardiac troponin (cTn, the current "gold standard" surrogate biomarker of myocardial damage.The concentration of exosome-sized nanoparticles was determined in serial plasma samples. Cardiac-expressed (miR-1, miR-24, miR-133a/b, miR-208a/b, miR-210, non-cardiovascular (miR-122 and quality control miRs were measured in whole plasma and in plasma exosomes. Linear regression analyses were employed to establish the extent to which the circulating individual miRs, exosomes and exosomal cardiac miR correlated with cTn-I. Cardiac-expressed miRs and the nanoparticle number increased in the plasma on completion of surgery for up to 48 hours. The exosomal concentration of cardiac miRs also increased after CABG. Cardiac miRs in the whole plasma did not correlate significantly with cTn-I. By contrast cTn-I was positively correlated with the plasma exosome level and the exosomal cardiac miRs.The plasma concentrations of exosomes and their cargo of cardiac miRs increased in patients undergoing CABG and were positively correlated with hs-cTnI. These data provide evidence that CABG induces the trafficking of exosomes from the heart to the peripheral circulation. Future studies are necessary to investigate the potential of circulating exosomes as clinical biomarkers in cardiac patients.

  19. Changes in Permeability Produced By Distant Earthquakes (United States)

    Manga, M.; Wang, C. Y.; Shi, Z.


    Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10-6 can increase discharge in streams and springs, change the water level of wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to pre-stimulated values over a period of months to years. This presentation will review some of the observations that indicate that dynamic stresses produced by seismic waves change permeability. We use the response of a set of wells distributed throughout China to multiple large earthquakes to probe the relationship between earthquake-generated stresses and water-level changes in wells. We find that dynamic stresses dominate the responses at distances more than 1 fault length from the earthquake and that permeability changes may explain the water level changes. Regions with high deformation rates are most sensitive to seismic waves. We also consider the response of a large alluvial fan in Taiwan to the 1999 M7.5 Chi-Chi earthquake where there were sustained changes in groundwater temperature after the earthquake. Using groundwater flow models, we infer that permeability increased by an order of magnitude over horizontal scales of tens of km, and vertical scales of several km. Permeability returned to the pre-earthquake value over many months. As much as half the total transport in the fan occurs during the short time periods with enhanced permeability.

  20. Your diet after gastric bypass surgery (United States)

    Gastric bypass surgery - your diet; Obesity - diet after bypass; Weight loss - diet after bypass ... completely. Some of these are pasta, rice, bread, raw vegetables, and meats. Adding a low-fat sauce, ...

  1. Stressors and anxiety in patients undergoing coronary artery bypass surgery

    National Research Council Canada - National Science Library

    Gallagher, Robyn; McKinley, Sharon


    Patients undergoing coronary artery bypass surgery who have increased anxiety levels have poorer outcomes than patients with lower levels, yet few studies have identified the concerns associated with this anxiety...

  2. Coronary Artery Bypass

    Directory of Open Access Journals (Sweden)

    Kadri Ceberut


    Full Text Available Ancient schwannoma is a rare variant of neural tumors though rarely seen in the thorax. The combination with coronary artery diseases is also rare. Here we describe a 66 year-old male who had undergone one-stage combined surgery for thoracic ancient schwannomas removal and coronary artery disease. The masses were, respectively, 13 cm in the middle mediastinum and 5 cm in diameter originating from the intercostal nerve. The tumors were successfully removed using sternotomy, and then a coronary artery bypass grafting was performed. Here we discuss this rare tumor in relation to the relevant literature.

  3. Impact of Norepinephrine on Regional Cerebral Oxygenation During Cardiopulmonary Bypass. (United States)

    Hagen, Ove Andreas; Høiseth, Lars Øivind; Roslin, André; Landsverk, Svein Aslak; Woldbaek, Per Reidar; Pripp, Are Hugo; Hanoa, Rolf; Kirkebøen, Knut Arvid


    Norepinephrine is used to increase mean arterial pressure during cardiopulmonary bypass. However, it has been suggested that norepinephrine could constrict cerebral arteries, reducing cerebral blood flow. The aim of this study, therefore, was to explore whether there was an association between doses of norepinephrine to maintain mean arterial pressure at ≈80 mmHg during cardiopulmonary bypass and cerebral oxygen saturation measured using near-infrared spectroscopy. Observational study. University hospital. Patients undergoing cardiac surgery (n = 45) using cardiopulmonary bypass. Norepinephrine was administered to maintain mean arterial pressure ≈80 mmHg during cardiopulmonary bypass. From initiation of cardiopulmonary bypass to removal of the aortic cross-clamp, norepinephrine dose, mean arterial pressure, partial pressure of arterial carbon dioxide, partial pressure of arterial oxygen, hemoglobin, and pump flow values were averaged over 1 minute, giving a total of 3,460 data points entered as covariates in a linear mixed model for repeated measurements, with cerebral oxygen saturation measured using near-infrared spectroscopy as outcome. There was no statistically significant association between norepinephrine dose to maintain mean arterial pressure and cerebral oxygen saturation (p = 0.46) in this model. Administration of norepinephrine to maintain mean arterial pressure ≈80 mmHg during cardiopulmonary bypass was not associated with statistically significant changes in cerebral oxygen saturation. These results indicated that norepinephrine could be used to increase mean arterial pressure during cardiopulmonary bypass without reducing cerebral oxygen saturation. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Frictional stability-permeability relationships for fractures in shales: Friction-Permeability Relationships

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Yi [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Elsworth, Derek [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Department of Geosciences, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Wang, Chaoyi [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Ishibashi, Takuya [Department of Energy and Mineral Engineering, EMS Energy Institute, and G3 Center, Pennsylvania State University, University Park Pennsylvania USA; Fukushima Renewable Energy Institute, National Institute of Advanced Industrial Science and Technology, Koriyama Japan; Fitts, Jeffrey P. [Department of Civil and Environmental Engineering, Princeton University, Princeton New Jersey USA


    There is wide concern that fluid injection in the subsurface, such as for the stimulation of shale reservoirs or for geological CO2 sequestration (GCS), has the potential to induce seismicity that may change reservoir permeability due to fault slip. However, the impact of induced seismicity on fracture permeability evolution remains unclear due to the spectrum of modes of fault reactivation (e.g., stable versus unstable). As seismicity is controlled by the frictional response of fractures, we explore friction-stability-permeability relationships through the concurrent measurement of frictional and hydraulic properties of artificial fractures in Green River shale (GRS) and Opalinus shale (OPS). We observe that carbonate-rich GRS shows higher frictional strength but weak neutral frictional stability. The GRS fracture permeability declines during shearing while an increased sliding velocity reduces the rate of permeability decline. By comparison, the phyllosilicate-rich OPS has lower friction and strong stability while the fracture permeability is reduced due to the swelling behavior that dominates over the shearing induced permeability reduction. Hence, we conclude that the friction-stability-permeability relationship of a fracture is largely controlled by mineral composition and that shale mineral compositions with strong frictional stability may be particularly subject to permanent permeability reduction during fluid infiltration.

  5. Comparative field permeability measurement of permeable pavements using ASTM C1701 and NCAT permeameter methods. (United States)

    Li, Hui; Kayhanian, Masoud; Harvey, John T


    Fully permeable pavement is gradually gaining support as an alternative best management practice (BMP) for stormwater runoff management. As the use of these pavements increases, a definitive test method is needed to measure hydraulic performance and to evaluate clogging, both for performance studies and for assessment of permeability for construction quality assurance and maintenance needs assessment. Two of the most commonly used permeability measurement tests for porous asphalt and pervious concrete are the National Center for Asphalt Technology (NCAT) permeameter and ASTM C1701, respectively. This study was undertaken to compare measured values for both methods in the field on a variety of permeable pavements used in current practice. The field measurements were performed using six experimental section designs with different permeable pavement surface types including pervious concrete, porous asphalt and permeable interlocking concrete pavers. Multiple measurements were performed at five locations on each pavement test section. The results showed that: (i) silicone gel is a superior sealing material to prevent water leakage compared with conventional plumbing putty; (ii) both methods (NCAT and ASTM) can effectively be used to measure the permeability of all pavement types and the surface material type will not impact the measurement precision; (iii) the permeability values measured with the ASTM method were 50-90% (75% on average) lower than those measured with the NCAT method; (iv) the larger permeameter cylinder diameter used in the ASTM method improved the reliability and reduced the variability of the measured permeability. Copyright © 2013 Elsevier Ltd. All rights reserved.

  6. Heart bypass surgery - minimally invasive - discharge (United States)

    Minimally invasive direct coronary artery bypass - discharge; MIDCAB - discharge; Robot assisted coronary artery bypass - discharge; RACAB - discharge; Keyhole heart surgery - discharge; Coronary artery disease - MIDCAB discharge; CAD - ...

  7. Rural health care bypass behavior: how community and spatial characteristics affect primary health care selection. (United States)

    Sanders, Scott R; Erickson, Lance D; Call, Vaughn R A; McKnight, Matthew L; Hedges, Dawson W


    (1) To assess the prevalence of rural primary care physician (PCP) bypass, a behavior in which residents travel farther than necessary to obtain health care, (2) To examine the role of community and non-health-care-related characteristics on bypass behavior, and (3) To analyze spatial bypass patterns to determine which rural communities are most affected by bypass. Data came from the Montana Health Matters survey, which gathered self-reported information from Montana residents on their health care utilization, satisfaction with health care services, and community and demographic characteristics. Logistic regression and spatial analysis were used to examine the probability and spatial patterns of bypass. Overall, 39% of respondents bypass local health care. Similar to previous studies, dissatisfaction with local health care was found to increase the likelihood of bypass. Dissatisfaction with local shopping also increases the likelihood of bypass, while the number of friends in a community, and commonality with community reduce the likelihood of bypass. Other significant factors associated with bypass include age, income, health, and living in a highly rural community or one with high commuting flows. Our results suggest that outshopping theory, in which patients bundle services and shopping for added convenience, extends to primary health care selection. This implies that rural health care selection is multifaceted, and that in addition to perceived satisfaction with local health care, the quality of local shopping and levels of community attachment also influence bypass behavior. © 2014 National Rural Health Association.

  8. Spiritual Bypass: A Preliminary Investigation (United States)

    Cashwell, Craig S.; Glosoff, Harriet L.; Hammond, Cheree


    The phenomenon of spiritual bypass has received limited attention in the transpersonal psychology and counseling literature and has not been subjected to empirical inquiry. This study examines the phenomenon of spiritual bypass by considering how spirituality, mindfulness, alexithymia (emotional restrictiveness), and narcissism work together to…

  9. Fundametal Study On Permeability Pavement


    川口, 基広; 建部, 英博


    This study aimed at the thing which develops a water permeability pavement which improved a drainage pavement. Then it examined possibility of the permeability pavement which can secure water permeability and strength, which it uses water granulated iron-blast-furnace slag in subgrade roadbed and it makes an asphalt mixture mix a stainless steel fiber, to solve a problem of permeability pavement

  10. Completion and fracture modeling of low-permeability gas sand in south Texas enhanced by magnetic resonance and sound wave technology

    Energy Technology Data Exchange (ETDEWEB)

    Fairhurst, D. L.; Marfice, J. P. [Schlumberger Oilfield Services Inc (United States); Seim, M. R.; Norville, M. A. [Kerns Oil and Gas Inc (United States)


    Recent advances in well logging, which involve the application of sound wave forms and magnetic resonance technology and result in more accurate shear modulus and permeability estimates, are discussed. In some cases, use of magnetic resonance has identified previously bypassed permeable streaks that increased production. In others, sonic waveforms technology has helped determine fracture direction, which led to better gas drainage and well placement. The model incorporating these techniques has been found to produce good results for completions in the Olmos and San Miguel sands of south Texas. This paper presents comparisons between field data with model predictions to illustrate how use of the model can improve both productivity estimates as well as fracture design parameters for tight sand formations. 14 refs., 12 figs., 1 appendix.

  11. The Staphylococcus aureus FASII bypass escape route from FASII inhibitors. (United States)

    Morvan, Claire; Halpern, David; Kénanian, Gérald; Pathania, Amit; Anba-Mondoloni, Jamila; Lamberet, Gilles; Gruss, Alexandra; Gloux, Karine


    Antimicrobials targeting the fatty acid synthesis (FASII) pathway are being developed as alternative treatments for bacterial infections. Emergence of resistance to FASII inhibitors was mainly considered as a consequence of mutations in the FASII target genes. However, an alternative and efficient anti-FASII resistance strategy, called here FASII bypass, was uncovered. Bacteria that bypass FASII incorporate exogenous fatty acids in membrane lipids, and thus dispense with the need for FASII. This strategy is used by numerous Gram-positive low GC % bacteria, including streptococci, enterococci, and staphylococci. Some bacteria repress FASII genes once fatty acids are available, and "constitutively" shift to FASII bypass. Others, such as the major pathogen Staphylococcus aureus, can undergo high frequency mutations that favor FASII bypass. This capacity is particularly relevant during infection, as the host supplies the fatty acids needed for bacteria to bypass FASII and thus become resistant to FASII inhibitors. Screenings for anti-FASII resistance in the presence of exogenous fatty acids confirmed that FASII bypass confers anti-FASII resistance among clinical and veterinary isolates. Polymorphisms in S. aureus FASII initiation enzymes favor FASII bypass, possibly by increasing availability of acyl-carrier protein, a required intermediate. Here we review FASII bypass and consequences in light of proposed uses of anti-FASII to treat infections, with a focus on FASII bypass in S. aureus. Copyright © 2017 Elsevier B.V. and Société Française de Biochimie et Biologie Moléculaire (SFBBM). All rights reserved.

  12. Comparison of two technics of cardiopulmonary bypass (conventional and mini CPB) in the trans-and postoperative periods of cardiac surgery. (United States)

    Pereira, Sergio Nunes; Zumba, Izabelle Balta; Batista, Micheline Sulzbacher; Pieve, Daniela da; Santos, Elisandra dos; Stuermer, Ralf; Oliveira, Gerson Pereira de; Senger, Roberta


    This study aimed to compare the effects of two different perfusion techniques: conventional cardiopulmonary bypass and miniature cardiopulmonary bypass in patients undergoing cardiac surgery at the University Hospital of Santa Maria--RS. We perform a retrospective, cross-sectional study, based on data collected from the patients operated between 2010 and 2013. We analyzed the records of 242 patients divided into two groups: Group I: 149 patients undergoing cardiopulmonary bypass and Group II - 93 patients undergoing the miniature cardiopulmonary bypass. The clinical profile of patients in the preoperative period was similar in the cardiopulmonary bypass and miniature cardiopulmonary bypass groups without significant differences, except in age, which was greater in the miniature cardiopulmonary bypass group. The perioperative data were significant of blood collected for autotransfusion, which were higher in the group with miniature cardiopulmonary bypass than the cardiopulmonary bypass and in transfusion of packed red blood cells, which was higher in cardiopulmonary bypass than in miniature cardiopulmonary bypass. In the immediate, first and second postoperative period the values of hematocrit and hemoglobin were higher and significant in miniature cardiopulmonary bypass than in the cardiopulmonary bypass, although the bleeding in the first and second postoperative days was higher and significant in miniature cardiopulmonary bypass than in the cardiopulmonary bypass. The present results suggest that the miniature cardiopulmonary bypass was beneficial in reducing the red blood cell transfusion during surgery and showed slight but significant increase in hematocrit and hemoglobin in the postoperative period.

  13. Concentrations of lipopolysaccharide-binding protein, bactericidal/permeability-increasing protein, soluble CD14 and plasma lipids in relation to endotoxaemia in patients with alcoholic liver disease

    DEFF Research Database (Denmark)

    Schäfer, C.; Parlesak, Alexandr; Schütt, C.


    in these patients. To analyse this phenomenon, we measured the concentration of functionally important endotoxin-binding plasma components which modify the action of endotoxin. In patients with minimal (n = 10), intermediate (n = 9), and cirrhotic alcoholic liver disease (n = 11), and healthy controls (n = 11......), plasma endotoxin was determined in a limulus assay. The concentration of lipoproteins was assessed by measuring apolipoproteins, the other factors were directly measured in immunoassays. In the entire group of alcoholics, endotoxin and the concentration of binding factors that are involved in the action......There is increasing evidence that gut leakage in persons with chronic alcohol misuse leads to endotoxaemia, which might contribute to the development of alcoholic hepatitis or cirrhosis. In addition, it was recently shown that the endotoxin-binding capacity of whole blood is reduced...

  14. A Chitin-binding Protein Purified from Moringa oleifera Seeds Presents Anticandidal Activity by Increasing Cell Membrane Permeability and Reactive Oxygen Species Production. (United States)

    Neto, João X S; Pereira, Mirella L; Oliveira, Jose T A; Rocha-Bezerra, Lady C B; Lopes, Tiago D P; Costa, Helen P S; Sousa, Daniele O B; Rocha, Bruno A M; Grangeiro, Thalles B; Freire, José E C; Monteiro-Moreira, Ana Cristina O; Lobo, Marina D P; Brilhante, Raimunda S N; Vasconcelos, Ilka M


    Candida species are opportunistic pathogens that infect immunocompromised and/or immunosuppressed patients, particularly in hospital facilities, that besides representing a significant threat to health increase the risk of mortality. Apart from echinocandins and triazoles, which are well tolerated, most of the antifungal drugs used for candidiasis treatment can cause side effects and lead to the development of resistant strains. A promising alternative to the conventional treatments is the use of plant proteins. M. oleifera Lam. is a plant with valuable medicinal properties, including antimicrobial activity. This work aimed to purify a chitin-binding protein from M. oleifera seeds and to evaluate its antifungal properties against Candida species. The purified protein, named Mo-CBP2, represented about 0.2% of the total seed protein and appeared as a single band on native PAGE. By mass spectrometry, Mo-CBP2 presented 13,309 Da. However, by SDS-PAGE, Mo-CBP2 migrated as a single band with an apparent molecular mass of 23,400 Da. Tricine-SDS-PAGE of Mo-CBP2 under reduced conditions revealed two protein bands with apparent molecular masses of 7,900 and 4,600 Da. Altogether, these results suggest that Mo-CBP2 exists in different oligomeric forms. Moreover, Mo-CBP2 is a basic glycoprotein (pI 10.9) with 4.1% (m/m) sugar and it did not display hemagglutinating and hemolytic activities upon rabbit and human erythrocytes. A comparative analysis of the sequence of triptic peptides from Mo-CBP2 in solution, after LC-ESI-MS/MS, revealed similarity with other M. oleifera proteins, as the 2S albumin Mo-CBP3 and flocculating proteins, and 2S albumins from different species. Mo-CBP2 possesses in vitro antifungal activity against Candida albicans, C. parapsilosis, C. krusei, and C. tropicalis, with MIC50 and MIC90 values ranging between 9.45-37.90 and 155.84-260.29 μM, respectively. In addition, Mo-CBP2 (18.90 μM) increased the cell membrane permeabilization and reactive oxygen

  15. A Chitin-binding Protein Purified from Moringa oleifera Seeds Presents Anticandidal Activity by Increasing Cell Membrane Permeability and Reactive Oxygen Species Production

    Directory of Open Access Journals (Sweden)

    João X.S. Neto


    Full Text Available Candida species are opportunistic pathogens that infect immunocompromised and/or immunosuppressed patients, particularly in hospital facilities, that besides representing a significant threat to health increase the risk of mortality. Apart from echinocandins and triazoles, which are well tolerated, most of the antifungal drugs used for candidiasis treatment can cause side effects and lead to the development of resistant strains. A promising alternative to the conventional treatments is the use of plant proteins. M. oleifera Lam. is a plant with valuable medicinal properties, including antimicrobial activity. This work aimed to purify a chitin-binding protein from M. oleifera seeds and to evaluate its antifungal properties against Candida species. The purified protein, named Mo-CBP2, represented about 0.2% of the total seed protein and appeared as a single band on native PAGE. By mass spectrometry, Mo-CBP2 presented 13,309 Da. However, by SDS-PAGE, Mo-CBP2 migrated as a single band with an apparent molecular mass of 23,400 Da. Tricine-SDS-PAGE of Mo-CBP2 under reduced conditions revealed two protein bands with apparent molecular masses of 7,900 and 4,600 Da. Altogether, these results suggest that Mo-CBP2 exists in different oligomeric forms. Moreover, Mo-CBP2 is a basic glycoprotein (pI 10.9 with 4.1% (m/m sugar and it did not display hemagglutinating and hemolytic activities upon rabbit and human erythrocytes. A comparative analysis of the sequence of triptic peptides from Mo-CBP2 in solution, after LC-ESI-MS/MS, revealed similarity with other M. oleifera proteins, as the 2S albumin Mo-CBP3 and flocculating proteins, and 2S albumins from different species. Mo-CBP2 possesses in vitro antifungal activity against Candida albicans, C. parapsilosis, C. krusei, and C. tropicalis, with MIC50 and MIC90 values ranging between 9.45–37.90 and 155.84–260.29 μM, respectively. In addition, Mo-CBP2 (18.90 μM increased the cell membrane permeabilization

  16. Biostable glucose permeable polymer

    DEFF Research Database (Denmark)


    A new biostable glucose permeable polymer has been developed which is useful, for example, in implantable glucose sensors. This biostable glucose permeable polymer has a number of advantageous characteristics and, for example, does not undergo hydrolytic cleavage and degradation, thereby providing...... a composition that facilitates long term sensor stability in vivo. The versatile characteristics of this polymer allow it to be used in a variety of contexts, for example to form the body of an implantable glucose sensor. The invention includes the polymer composition, sensor systems formed from this polymer...

  17. Biopartitioning micellar chromatography to predict skin permeability. (United States)

    Martínez-Pla, J J; Martín-Biosca, Y; Sagrado, S; Villanueva-Camañas, R M; Medina-Hernández, M J


    Dermal absorption of chemicals is an area of increasing interest to the pharmaceutical and cosmetic industries, as well as in dermal exposure and risk assessment processes. In this paper the capability of biopartitioning micellar chromatography (BMC) as an in vitro technique to describe compound percutaneous absorption is evaluated. A multivariate study (principal component analysis, partial least squares) is performed in order to evaluate the importance of some physicochemical variables on the skin permeability constant values. From these results, a quantitative retention-activity relationship model for predicting the skin permeability constants that uses the BMC retention data and melting point as descriptor variables was obtained from a heterogeneous set of 43 compounds. The main advantage of the proposed methodology is that it allows the obtention of permeability constants of ionic compound and it can be very useful to predict the effect of pH of vehicle on the skin permeability of xenobiotics. Copyright 2003 John Wiley & Sons, Ltd.

  18. Oil Bypass Filter Technology Performance Evaluation - January 2003 Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Laurence R. Zirker; James E. Francfort


    This report details the initial activities to evaluate the performance of the oil bypass filter technology being tested by the Idaho National Engineering and Environmental Laboratory (INEEL) for the U.S. Department of Energy's FreedomCAR & Vehicle Technologies Program. Eight full-size, four-cycle diesel-engine buses used to transport INEEL employees on various routes have been equipped with oil bypass systems from the puraDYN Corporation. Each bus averages about 60,000 miles a year. The evaluation includes an oil analysis regime to monitor the presence of necessary additives in the oil and to detect undesirable contaminants. Very preliminary economic analysis suggests that the oil bypass system can reduce life-cycle costs. As the evaluation continues and oil avoidance costs are quantified, it is estimated that the bypass system economics may prove increasingly favorable, given the anticipated savings in operational costs and in reduced use of oil and waste oil avoidance.

  19. Oil Bypass Filter Technology Performance Evaluation - First Quarterly Report

    Energy Technology Data Exchange (ETDEWEB)

    Zirker, L.R.; Francfort, J.E.


    This report details the initial activities to evaluate the performance of the oil bypass filter technology being tested by the Idaho National Engineering and Environmental Laboratory (INEEL) for the U.S. Department of Energy's FreedomCAR & Vehicle Technologies Program. Eight full-size, four-cycle diesel-engine buses used to transport INEEL employees on various routes have been equipped with oil bypass systems from the puraDYN Corporation. Each bus averages about 60,000 miles a year. The evaluation includes an oil analysis regime to monitor the presence of necessary additives in the oil and to detect undesirable contaminants. Very preliminary economic analysis suggests that the oil bypass system can reduce life-cycle costs. As the evaluation continues and oil avoidance costs are quantified, it is estimated that the bypass system economics may prove increasingly favorable, given the anticipated savings in operational costs and in reduced use of oil and waste oil avoidance.

  20. Hypoparathyroidism after total thyroidectomy in patients with previous gastric bypass. (United States)

    Droeser, Raoul A; Ottosson, Johan; Muth, Andreas; Hultin, Hella; Lindwall-Åhlander, Karin; Bergenfelz, Anders; Almquist, Martin


    Case reports suggest that patients with previous gastric bypass have an increased risk of severe hypocalcemia after total thyroidectomy, but there are no population-based studies. The prevalence of gastric bypass before thyroidectomy and the risk of hypocalcemia after thyroidectomy in patients with previous gastric bypass were investigated. By cross-linking The Scandinavian Quality Registry for Thyroid, Parathyroid and Adrenal Surgery with the Scandinavian Obesity Surgery Registry patients operated with total thyroidectomy without concurrent or previous surgery for hyperparathyroidism were identified and grouped according to previous gastric bypass. The risk of treatment with intravenous calcium during hospital stay, and with oral calcium and vitamin D at 6 weeks and 6 months postoperatively was calculated by using multiple logistic regression in the overall cohort and in a 1:1 nested case-control analysis. We identified 6115 patients treated with total thyroidectomy. Out of these, 25 (0.4 %) had undergone previous gastric bypass surgery. In logistic regression, previous gastric bypass was not associated with treatment with i.v. calcium (OR 2.05, 95 % CI 0.48-8.74), or calcium and/or vitamin D at 6 weeks (1.14 (0.39-3.35), 1.31 (0.39-4.42)) or 6 months after total thyroidectomy (1.71 (0.40-7.32), 2.28 (0.53-9.75)). In the nested case-control analysis, rates of treatment for hypocalcemia were similar in patients with and without previous gastric bypass. Previous gastric bypass surgery was infrequent in patients undergoing total thyroidectomy and was not associated with an increased risk of postoperative hypocalcemia.

  1. Reconnaissance Report Yolo Bypass, California

    National Research Council Canada - National Science Library


    The purpose of this study was to investigate flooding and related water resources problems associated with the Yolo Bypass and determine the Federal interest in proceeding into feasibility phase studies...

  2. Heart bypass surgery - minimally invasive (United States)

    ... and lifestyle Cholesterol - drug treatment Controlling your high blood pressure Dietary fats explained Fast food tips Heart attack - discharge Heart attack - what to ask your doctor Heart bypass surgery - minimally invasive - discharge Heart disease - risk factors Heart pacemaker - discharge ...

  3. Variations in dietary intake after bypass surgery for obesity. Possible relation to development of fatty liver after jejunoileal bypass

    Energy Technology Data Exchange (ETDEWEB)

    Rogus, J.; Blumenthal, S.A.


    Consumption of nutrients and food energy was compared, with concomitant chemical and radiologic measurements of hepatic fat content, preoperatively and postoperatively in 25 patients who underwent gastric or jejunoileal bypass for obesity. Patients in the two operative groups ingested similar quantities of food before surgery. After surgery, caloric intake from all sources decreased in both groups but to a significantly greater extent in the gastric bypass patients. During the first six months postoperatively, the 13 gastric bypass patients showed no changes in hepatic fat content, whereas substantial increases in liver fat uniformly occurred in the 12 patients who had jejunoileal bypasses. It is suggested that dietary carbohydrate may have contributed to the accretion of liver fat in these 12 patients.

  4. Intestinal permeability in patients with atopic eczema. (United States)

    Bjarnason, I; Goolamali, S K; Levi, A J; Peters, T J


    Intestinal permeability was investigated in adult patients with atopic eczema by in vivo and in vitro techniques. Patients with symptoms of 'immediate' food allergy were specifically excluded. A 51Cr-labelled ethylenediaminetetraacetate absorption test was carried out in eighteen patients. Their mean (+/- s.d.) 24-hour urine excretion following oral administration of the test substance (2.1 +/- 0.9%) did not differ significantly from that of thirty-four normal controls (1.9 +/- 0.5%). Small bowel permeability was estimated directly in jejunal mucosal samples in ten patients with three permeability probes of differing molecular weight. Mucosal permeability did not differ significantly from that of fifteen control patients for any of the test substances. Two patients had abnormal results by both tests and in one this was due to coeliac disease. These results suggest that altered intestinal permeability is not important in the pathogenesis of eczema. Patients demonstrating increased intestinal permeability should undergo jejunal biopsy to exclude significant small bowel disease.

  5. Assessing Patient bypass Behavior Using Taxi Trip Origin–Destination (OD Data

    Directory of Open Access Journals (Sweden)

    Gege Yang


    Full Text Available Many patients prefer to use the best hospitals even if there are one or more other hospitals closer to their homes; this behavior is called “hospital bypass behavior”. Because this behavior can be problematic in urban areas, it is important that it be reduced. In this paper, the taxi GPS data of Beijing and Suzhou were used to measure hospital bypass behavior. The “bypass behavior index” (BBI represents the bypass behavior for each hospital. The results indicated that the mean hospital bypass trip distance value ranges from 5.988 km to 9.754 km in Beijing and from 4.168 km to 10.283 km in Suzhou. In general, the bypass shares of both areas show a gradually increasing trend. The following hospitals exhibited significant patient bypass behavior: the 301 Hospital, Beijing Children’s Hospital, the Second Affiliated Hospital of Soochow University and the Suzhou Hospital of Traditional Chinese Medicine. The hospitals’ reputation, transport accessibility and spatial distribution were found to be the main factors affecting patient bypass behavior. Although the hospital bypass phenomena generally appeared to be more pronounced in Beijing, the bypass trip distances between hospitals were found to be more significant in Suzhou.

  6. Progress on Complications of Direct Bypass for Moyamoya Disease. (United States)

    Yu, Jinlu; Shi, Lei; Guo, Yunbao; Xu, Baofeng; Xu, Kan


    Moyamoya disease (MMD) involves progressive occlusion of the intracranial internal carotid artery resulting in formation of moyamoya-like vessels at the base of the brain. It can be characterized by hemorrhage or ischemia. Direct vascular bypass is the main and most effective treatment of MMD. However, patients with MMD differ from those with normal cerebral vessels. MMD patients have unstable intracranial artery hemodynamics and a poor blood flow reserve; therefore, during the direct bypass of superficial temporal artery (STA)-middle cerebral artery (MCA) anastomosis, perioperative risk factors and anesthesia can affect the hemodynamics of these patients. When brain tissue cannot tolerate a high blood flow rate, it becomes prone to hyperperfusion syndrome, which leads to neurological function defects and can even cause intracranial hemorrhage in severe cases. The brain tissue is prone to infarction when hemodynamic equilibrium is affected. In addition, bypass vessels become susceptible to occlusion or atrophy when blood resistance increases. Even compression of the temporalis affects bypass vessels. Because the STA is used in MMD surgery, the scalp becomes ischemic and is likely to develop necrosis and infection. These complications of MMD surgery are difficult to manage and are not well understood. To date, no systematic studies of the complications that occur after direct bypass in MMD have been performed, and reported complications are hidden among various case studies; therefore, this paper presents a review and summary of the literature in PubMed on the complications of direct bypass in MMD.

  7. Oil recovery enhancement from fractured, low permeability reservoirs. Annual report 1990--1991, Part 1

    Energy Technology Data Exchange (ETDEWEB)

    Poston, S.W.


    Joint funding by the Department of Energy and the State of Texas has Permitted a three year, multi-disciplinary investigation to enhance oil recovery from a dual porosity, fractured, low matrix permeability oil reservoir to be initiated. The Austin Chalk producing horizon trending thru the median of Texas has been identified as the candidate for analysis. Ultimate primary recovery of oil from the Austin Chalk is very low because of two major technological problems. The commercial oil producing rate is based on the wellbore encountering a significant number of natural fractures. The prediction of the location and frequency of natural fractures at any particular region in the subsurface is problematical at this time, unless extensive and expensive seismic work is conducted. A major portion of the oil remains in the low permeability matrix blocks after depletion because there are no methods currently available to the industry to mobilize this bypassed oil. The following multi-faceted study is aimed to develop new methods to increase oil and gas recovery from the Austin Chalk producing trend. These methods may involve new geological and geophysical interpretation methods, improved ways to study production decline curves or the application of a new enhanced oil recovery technique. The efforts for the second year may be summarized as one of coalescing the initial concepts developed during the initial phase to more in depth analyses. Accomplishments are predicting natural fractures; relating recovery to well-log signatures; development of the EOR imbibition process; mathematical modeling; and field test.

  8. Passage of downstream migrant American eels through an airlift-assisted deep bypass (United States)

    Haro, Alexander J.; Watten, Barnaby J.; Noreika, John


    Traditional downstream guidance and bypass facilities for anadromous fishes (i.e., surface bypasses, surface guidance structures, and behavioral barriers) have frequently been ineffective for anguillid eels. Because eels typically spend the majority of their time near the bottom in the vicinity of intake structures, deep bypass structures with entrances near the bottom hold promise for increased effectiveness, thereby aiding in the recovery of this important species. A new design of a deep bypass system that uses airlift technology (the Conte Airlift Bypass) to induce flow in a bypass pipe was tested in a simulated intake entrance environment under controlled laboratory conditions. Water velocities of 0.9–1.5 m s−1 could be generated at the bypass entrance (opening with 0.073 m2 area), with corresponding flows through the bypass pipe of 0.07–0.11 m3 s−1. Gas saturation and hydrostatic pressure within the bypass pipe did not vary appreciably from a control (no air) condition under tested airflows. Migratory silver-phase American eels (Anguilla rostrata) tested during dark conditions readily located, entered, and passed through the bypass; initial avoidance rates (eels approaching but not entering the bypass entrance) were lower at higher entrance velocities. Eels that investigated the bypass pipe entrance tended to enter headfirst, but those that then exited the pipe upstream did so more frequently at lower entrance velocities. Eels appeared to swim against the flow while being transported downstream through the pipe; median transit times through the bypass for each test velocity ranged from 5.8 to 12.2 s, with transit time decreasing with increasing entrance velocity. Eels did not show strong avoidance of the vertical section of the pipe which contained injected air. No mortality or injury of bypassed eels was observed, and individual eels repeatedly passed through the bypass at rates of up to 40 passes per hour, suggesting that individuals do not

  9. Role of plasma bactericidal/permeability-increasing protein, group IIA phospholipase A(2), C-reactive protein, and white blood cell count in the early detection of severe sepsis in the emergency department. (United States)

    Uusitalo-Seppälä, Raija; Peuravuori, Heikki; Koskinen, Pertti; Vahlberg, Tero; Rintala, Esa M


    To study the diagnostic values of bactericidal/permeability-increasing protein (BPI), group IIA phospholipase A(2) (PLA(2)GIIA), white blood cell count (WBC), and C-reactive protein (CRP) in identifying severe sepsis upon admission in an emergency room. This was a single-centre prospective cohort study involving 525 adult patients admitted to the emergency room with suspected infection. Plasma samples were taken concurrently with the blood cultures. Forty-nine patients with severe sepsis and 476 other patients (58 with no systemic inflammatory response syndrome (SIRS) and no bacterial infection, 63 with bacterial infection but no SIRS, 53 with SIRS but no bacterial infection, and 302 with sepsis but no organ dysfunction) were evaluated. BPI and PLA(2)GIIA were measured by time-resolved fluoroimmunoassay, and CRP with an immunoturbidimetric assay. WBC was measured using an automatic cell counter. There was a positive correlation between the plasma levels of PLA(2)GIIA and CRP (Pearson's correlation coefficient 0.60, p sepsis from others (OR 1.37, 95% Cl 1.05-1.78, p = 0.019). After adjusting for confounders PLA(2)GIIA remained a significant independent predictor of severe sepsis. PLA(2)GIIA seemed to be superior to CRP, BPI, and WBC in differentiating patients with severe sepsis. BPI gave no additional information in this respect.

  10. Vascular permeability alterations induced by arsenic. (United States)

    Chen, Shih-Chieh; Tsai, Ming-Hsien; Wang, Hsiu-Jen; Yu, Hsin-Su; Chang, Louis W


    The impact of arsenic on the integrity of blood vessels in vivo via in situ exposure (local injection) of arsenic was investigated. Vascular permeability changes were evaluated by means of the Evans blue assay and the India ink tracer techniques. Rats were intravenously injected with Evans blue followed by intradermal injections of various doses of sodium arsenite on the back skins of the animals. Evans blue at different time points was extracted and assayed as indices of vascular leakage. Skin at various time point injection sites was sampled for arsenic measurement via graphite furnace atomic absorption spectroscopy. Our time course study with Evans blue technique demonstrated a biphasic pattern of vascular permeability change: an early phase of permeability reduction and a later phase of permeability promotion at all dose levels tested. The India ink tracer technique also demonstrated a time-correlated increase in vascular labelling in the tissues examined, signifying an increase in vascular leakage with time. Moreover, we found that despite an early increase in tissue arsenic content at time of injection, tissue arsenic declined rapidly and returned to near control levels after 30-60 min. Thus, an inverse correlation between tissue arsenic content and the extent of vascular permeability was apparent. This study provides the first demonstration that in situ exposure to arsenic will produce vascular dysfunction (vascular leakage) in vivo.

  11. Relative permeability through fractures

    Energy Technology Data Exchange (ETDEWEB)

    Diomampo, Gracel, P.


    The mechanism of two-phase flow through fractures is of importance in understanding many geologic processes. Currently, two-phase flow through fractures is still poorly understood. In this study, nitrogen-water experiments were done on both smooth and rough parallel plates to determine the governing flow mechanism for fractures and the appropriate methodology for data analysis. The experiments were done using a glass plate to allow visualization of flow. Digital video recording allowed instantaneous measurement of pressure, flow rate and saturation. Saturation was computed using image analysis techniques. The experiments showed that gas and liquid phases flow through fractures in nonuniform separate channels. The localized channels change with time as each phase path undergoes continues breaking and reforming due to invasion of the other phase. The stability of the phase paths is dependent on liquid and gas flow rate ratio. This mechanism holds true for over a range of saturation for both smooth and rough fractures. In imbibition for rough-walled fractures, another mechanism similar to wave-like flow in pipes was also observed. The data from the experiments were analyzed using Darcy's law and using the concept of friction factor and equivalent Reynold's number for two-phase flow. For both smooth- and rough-walled fractures a clear relationship between relative permeability and saturation was seen. The calculated relative permeability curves follow Corey-type behavior and can be modeled using Honarpour expressions. The sum of the relative permeabilities is not equal one, indicating phase interference. The equivalent homogeneous single-phase approach did not give satisfactory representation of flow through fractures. The graphs of experimentally derived friction factor with the modified Reynolds number do not reveal a distinctive linear relationship.

  12. Variational calculation of the effective fluid permeability of heterogeneous media (United States)

    Hristopulos, Dionissios T.; Christakos, George


    We evaluate the effective permeability of heterogeneous media with Gaussian local permeability disorder using the replica-variational approach. We obtain integral equations that determine the effective permeability kernel, and we study specific cases that admit analytical solutions. Specifically, in the case of homogeneous disorder we obtain a variational estimate for the uniform effective permeability. We compare the results of our analytical calculations with experimental and numerical data. Finally, we model the behavior of the effective permeability in the preasymptotic regime by means of momentum filters. Explicit finite-size expressions are obtained in terms of a support function that increases monotonically with the ratio of the support scale over the correlation length of the disorder. It is found that the asymptotic effective permeability is approached at a slower rate than expected.

  13. Therapeutic benefits of enhancing permeability barrier for atopic eczema

    Directory of Open Access Journals (Sweden)

    George Man


    Full Text Available The regulatory role of epidermal permeability barrier function in cutaneous inflammation has been well appreciated. While barrier disruption induces cutaneous inflammation, improvement of permeability barrier function alleviates inflammation. Studies have demonstrated that improvement of epidermal permeability barrier function not only prevents the development of atopic eczema, but also delays the relapse of these diseases. Moreover, enhancing the epidermal permeability barrier also alleviates atopic eczema. Furthermore, co-applications of barrier enhancing products with glucocorticoids can increase the therapeutic efficacy and reduce the adverse effects of glucocorticoids in the treatment of atopic eczema. Therefore, utilization of permeability barrier enhancing products alone or in combination with glucocorticoids could be a valuable approach in the treatment of atopic eczema. In this review, we discuss the benefits of improving the epidermal permeability barrier in the management of atopic eczema.

  14. Secondary and College LD Bypass Strategies. (United States)

    Mosby, Robert J.


    The author describes the Developmental By-Pass (DBP) Instructional technology for teaching secondary and college learning disabled (LD) students by allowing students to bypass ordering and organizational deficits. (SB)

  15. Doxycycline reduces cardiac matrix metalloproteinase-2 activity but does not ameliorate myocardial dysfunction during reperfusion in coronary artery bypass patients undergoing cardiopulmonary bypass. (United States)

    Schulze, Costas J; Castro, Michele M; Kandasamy, Arulmozhi D; Cena, Jonathan; Bryden, Courtney; Wang, Shoa H; Koshal, Arvind; Tsuyuki, Ross T; Finegan, Barry A; Schulz, Richard


    Matrix metalloproteinase-2 proteolyzes intracellular proteins in the heart and induces acute myocardial contractile dysfunction in ischemia-reperfusion injury. Doxycycline, a matrix metalloproteinase inhibitor, prevented matrix metalloproteinase-2-induced troponin I cleavage in rat hearts and improved contractile function following ischemia-reperfusion. In patients undergoing coronary artery bypass graft surgery with cardiopulmonary bypass, increased atrial matrix metalloproteinase-2 activity was inversely correlated with cardiac mechanical function at 3 hours reperfusion. We performed a study in patients with coronary artery disease undergoing primary elective coronary artery bypass graft surgery with cardiopulmonary bypass to determine whether doxycycline reduces cardiac mechanical dysfunction, matrix metalloproteinase activity, and troponin I degradation after reperfusion. Randomized, double-blinded, placebo-controlled study. University of Alberta Hospital. Forty-two patients with coronary artery disease undergoing coronary artery bypass graft surgery with cardiopulmonary bypass. Patients were randomized to receive either oral administration of 20 mg of doxycycline or matching placebo pill twice a day at least 2 days prior to surgery, on the day of surgery, and for the first 3 postoperative days. Left ventricular stroke work index was examined prior to cardiopulmonary bypass and at 24 hours reperfusion. Right atrial biopsies were collected before cardiopulmonary bypass and 10 minutes after aortic cross-clamp release to determine matrix metalloproteinase-2 activity and troponin I level. Blood was collected to determine matrix metalloproteinase activity and interleukin-6, C-reactive protein, and troponin I levels. Cardiac 72-kDa matrix metalloproteinase-2 activity was lower upon reperfusion in biopsies from the doxycycline group (p = 0.01), and the increase of matrix metalloproteinase-2 activity in the placebo group due to reperfusion did not appear in the

  16. In situ bypass og diabetes

    DEFF Research Database (Denmark)

    Jensen, Leif Panduro; Schroeder, T V; Lorentzen, J E


    From 1986 through to 1990 a total of 483 in situ bypass procedures were performed in 444 patients. Preoperative risk-factors were equally distributed among diabetic (DM) and non-diabetic (NDM) patients, except for smoking habits (DM:48%, NDM:64%, p = 0.002) and cardiac disease (DM:45%, NDM:29%, p...... decreased survival rate was found in diabetics (p bypass technique very useful in the treatment of critical ischaemia of the lower limb in diabetic patients. The overall results in diabetic patients, whether insulin-dependent or not, were equal to those in non...

  17. A Permeability-Porosity Relationship for Surface Deposition

    Energy Technology Data Exchange (ETDEWEB)

    Weir, G.J.; White, S.P.


    The changes to porosity and permeability resulting from surface deposition and early dissolution in an initial rhombohedral array of uniform spheres are calculated. Very rapid decreases of permeability result from early deposition, with 48% reduction predicted in permeability from 8% reduction in porosity. After deposition has caused about a 1% increase in the radii of the spherical array, relative permeability reductions vary approximately as the square of relative changes in porosity. These theoretical results are matched with experimental data of Ioti et al. and shown to be satisfactory in some cases, but for others, a more complex model of the porous medium is needed.

  18. Permeability measuremens of brazilian Eucalyptus

    Directory of Open Access Journals (Sweden)

    Marcio Rogério da Silva


    Full Text Available The permeability of Brazilian Eucalyptus grandis and Eucalyptus citriodora wood was measured in a custom build gas analysis chamber in order to determine which species could be successfully treated with preservatives. Liquid permeability was tested using an emulsion of Neen oil and a control of distillated water. Air was used to test the gas phase permeability. For both Eucalyptus grandis and Eucalyptus citriodora, the longitudinal permeability of gas was shown to be about twice as great as the liquid phase permeability. No radial permeability was observed for either wood. The permeability of air and water through the sapwood of Eucalyptus grandis was greater than that through the sapwood of Eucalyptus citriodora. The permeability of neen oil preservative through the sapwood of Eucalyptus grandis was also greater than through the sapwood of E. Citradora, but the difference was not statistically significant. Scanning Electron Microscopy images showed that the distribution and obstruction in the vessels could be correlated with observed permeability properties. Irrespective of the causes of differences in permeability between the species, the fluid phase flux through the sapwood of both species was significant, indicating that both Eucalyptus grandis and Eucalyptus citriodora could be successfully treated with wood preservative.

  19. Acetaminophen attenuates lipid peroxidation in children undergoing cardiopulmonary bypass. (United States)

    Simpson, Scott A; Zaccagni, Hayden; Bichell, David P; Christian, Karla G; Mettler, Bret A; Donahue, Brian S; Roberts, L Jackson; Pretorius, Mias


    Hemolysis, occurring during cardiopulmonary bypass, is associated with lipid peroxidation and postoperative acute kidney injury. Acetaminophen inhibits lipid peroxidation catalyzed by hemeproteins and in an animal model attenuated rhabdomyolysis-induced acute kidney injury. This pilot study tests the hypothesis that acetaminophen attenuates lipid peroxidation in children undergoing cardiopulmonary bypass. Single-center prospective randomized double-blinded study. University-affiliated pediatric hospital. Thirty children undergoing elective surgical correction of a congenital heart defect. Patients were randomized to acetaminophen (OFIRMEV [acetaminophen] injection; Cadence Pharmaceuticals, San Diego, CA) or placebo every 6 hours for four doses starting before the onset of cardiopulmonary bypass. Markers of hemolysis, lipid peroxidation (isofurans and F2-isoprostanes), and acute kidney injury were measured throughout the perioperative period. Cardiopulmonary bypass was associated with a significant increase in free hemoglobin (from a prebypass level of 9.8 ± 6.2 mg/dL to a peak of 201.5 ± 42.6 mg/dL postbypass). Plasma and urine isofuran and F2-isoprostane concentrations increased significantly during surgery. The magnitude of increase in plasma isofurans was greater than the magnitude in increase in plasma F2-isoprostanes. Acetaminophen attenuated the increase in plasma isofurans compared with placebo (p = 0.02 for effect of study drug). There was no significant effect of acetaminophen on plasma F2-isoprostanes or urinary makers of lipid peroxidation. Acetaminophen did not affect postoperative creatinine, urinary neutrophil gelatinase-associated lipocalin, or prevalence of acute kidney injury. Cardiopulmonary bypass in children is associated with hemolysis and lipid peroxidation. Acetaminophen attenuated the increase in plasma isofuran concentrations. Future studies are needed to establish whether other therapies that attenuate or prevent the effects of free

  20. Undiagnosed phaeochromocytoma following infrainguinal bypass surgery

    DEFF Research Database (Denmark)

    Levi, N; Schroeder, T V


    We present a rare case of undiagnosed phaeochromocytoma following infrainguinal bypass surgery. The patient, a 59-year-old lady, had a one year history of hypertension following a first femoro-tibial bypass and presented as a cardiorespiratory emergency in the admission room following her...... contralateral femoro-tibial bypass. The patient recovered after some days in intensive care despite a delayed diagnosis....

  1. Deep-water sediment bypass

    NARCIS (Netherlands)

    Stevenson, Christopher J.; Jackson, Christopher A L; Hodgson, David M.; Hubbard, Stephen M.; Eggenhuisen, Joris T.|info:eu-repo/dai/nl/322850274

    Submarine gravity flows are a key process for transporting large volumes of sediment from the continents to the deep sea. The location, volume, and character of the sediment bypassed by these flows dictates the areal extent and thickness of the associated deposits. Despite its importance, sediment

  2. Choroidal changes after cardiopulmonary bypass. (United States)

    Pekel, G; Alur, I; Alihanoglu, Y I; Yagci, R; Emrecan, B


    Choroid, which is the vascular tissue responsible for blood supply to the outer parts of the retina, might be affected by hemodynamic events. We aimed to reveal choroidal thickness and ocular pulse amplitude changes after cardiopulmonary bypass in which gross hemodynamic alterations occur. Forty-two eyes of 42 patients who underwent heart surgery with cardiopulmonary bypass were examined in this prospective, cross-sectional case series. The spectral domain optical coherence tomography (Spectralis, Heidelberg, Germany) was used to analyze sub-foveal choroidal thickness. The ocular pulse amplitude, the surrogate of gross choroidal blood flow, was measured with the Pascal dynamic contour tonometer (Pascal DCT, Swiss Microtechnology AG, Port, Switzerland).. The intraocular pressure was also measured with this tonometer. The examinations were performed pre-operatively and post-operatively at the first week and first month. The mean age of the patients was 58.8 ± 12.4 years. The mean sub-foveal choroidal thickness and ocular pulse amplitude values did not change statistically significantly after the operations at the follow-up visits (p>0.05). Also, there were no important correlations between cardiopulmonary bypass time and mean sub-foveal choroidal thickness and ocular pulse amplitude changes at the post-operative first week (p>0.05). The intraocular pressure values were decreased markedly at the control visits (pcardiopulmonary bypass. © The Author(s) 2014.

  3. Low Permeability Polyimide Insulation Project (United States)

    National Aeronautics and Space Administration — Resodyn Technologies proposes a new technology that enables the application of polyimide based cryogenic insulation with low hydrogen permeability. This effort...

  4. The role of CB1 in intestinal permeability and inflammation. (United States)

    Karwad, Mustafa A; Couch, Daniel G; Theophilidou, Elena; Sarmad, Sarir; Barrett, David A; Larvin, Michael; Wright, Karen L; Lund, Jonathan N; O'Sullivan, Saoirse E


    The endocannabinoid system has previously been shown to play a role in the permeability and inflammatory response of the human gut. The goal of our study was to determine the effects of endogenous anandamide (AEA) and 2-arachidonoyl glycerol (2-AG) on the permeability and inflammatory response of intestinal epithelium under normal, inflammatory, and hypoxic conditions. Human intestinal mucosa was modeled using Caco-2 cells. Human tissue was collected from planned colorectal resections. Accumulation of AEA and 2-AG was achieved by inhibiting their metabolizing enzymes URB597 (a fatty acid amide hydrolase inhibitor) and JZL184 (a monoacylglycerol lipase inhibitor). Inflammation and ischemia were simulated with TNF-α and IFN-γ and oxygen deprivation. Permeability changes were measured by transepithelial electrical resistance. The role of the CB1 receptor was explored using CB1-knockdown (CB1Kd) intestinal epithelial cells. Endocannabinoid levels were measured using liquid chromatography-mass spectrometry. Cytokine secretion was measured using multiplex and ELISA. URB597 and JZL184 caused a concentration-dependent increase in permeability via CB1 (P permeability via CB1 (P permeability caused by inflammation and hypoxia (P permeability response to inflammation (P permeability and in inflammatory and hypoxic conditions.-Karwad, M. A., Couch, D. G., Theophilidou, E., Sarmad, S., Barrett, D. A., Larvin, M., Wright, K. L., Lund, J. N., O'Sullivan, S. E. The role of CB1 in intestinal permeability and inflammation. © FASEB.

  5. Endothelial monolayer permeability under controlled oxygen tension. (United States)

    Funamoto, Kenichi; Yoshino, Daisuke; Matsubara, Kento; Zervantonakis, Ioannis K; Funamoto, Kiyoe; Nakayama, Masafumi; Masamune, Jun; Kimura, Yoshitaka; Kamm, Roger D


    Endothelial permeability has been extensively investigated in the context of pathologies such as cancer and also in studies of drug delivery from the circulation. Hypoxia is a critical regulator of endothelial cell (EC) behavior and affects the barrier function of endothelial linings, yet its role has been little studied. This paper reveals the effect of hypoxia on the permeability of an EC monolayer by cellular experiments using a microfluidic device and a conventional cell culture dish. Human umbilical vein endothelial cells (HUVECs) were seeded into one microfluidic channel, creating an EC monolayer on each vertical surface of a collagen gel confined to a central chamber. Oxygen tension was regulated to produce normoxic (21% O2) or hypoxic (3% O2) conditions by the supply of gas mixtures of oxygen, carbon dioxide, and nitrogen at predefined ratios into channels fabricated into the device. Permeability of the EC monolayer quantified by analyzing diffusion of fluorescence-labelled dextrans into the collagen gel increases with barrier function loss by 6 hour hypoxic exposure, showing 11-fold and 4-fold increases for 70 kDa and 10 kDa dextrans, respectively, on average. Consistent with this, subsequent immunofluorescent staining and separate western blot analysis of HUVECs on a culture dish demonstrate loose cell-cell adhesion resulting from internalization of VE-cadherin under hypoxia. Thus, hypoxic stress increases endothelial permeability by altering cell-cell junction integrity.

  6. Hydraulic and geochemical performance of a permeable reactive barrier containing zero-valent iron, Denver Federal Center (United States)

    McMahon, P.B.; Dennehy, K.F.; Sandstrom, M.W.


    The hydraulic and geochemical performance of a 366 m long permeable reactive barrier (PRB) at the Denver Federal Center; Denver, Colorado, was evaluated. The funnel and gate system, which was installed in 1996 to intercept and remediate ground water contaminated with chlorinated aliphatic hydrocarbons (CAHs), contained four 12.2 m wide gates filled with zero-valent iron. Ground water mounding on the upgradient side of the PRB resulted in a tenfold increase in the hydraulic gradient and ground water velocity through the gates compared to areas of the aquifer unaffected by the PRB. Water balance calculations for April 1997 indicate that about 75% of the ground water moving toward the PRB from upgradient areas moved through the gates. The rest of the water either accumulated on the upgradient side of the PRB or bypassed the PRB. Chemical data from monitoring wells screened down-gradient, beneath, and at the ends of the PRB indicate that contaminants had not bypassed the PRB, except in a few isolated areas. Greater than 99% of the CAH mass entering the gates was retained by the iron. Fifty-one percent of the CAH carbon entering one gate was accounted for in dissolved C1 and C2 hydrocarbons, primarily ethane and ethene, which indicates that CAHs may adsorb to the iron prior to being dehalogenated. Treated water exiting the gates displaced contaminated ground water at a distance of at least 3 m downgradient from the PRB by the end of 1997. Measurements of dissolved inorganic ions in one gate indicate that calcite and siderite precipitation in the gate could reduce gate porosity by about 0.35% per year. Results from this study indicate that funnel and gate systems containing zero-valent iron can effectively treat ground water contaminated with CAHs. However, the hydrologic impacts of the PRB on the flow system need to be fully understood to prevent contaminants from bypassing the PRB.

  7. Temporary diabetes insipidus in 2 men after on-pump coronary artery bypass grafting. (United States)

    Uyar, Ihsan Sami; Sahin, Veysel; Akpinar, Besir; Yurtman, Volkan; Abacilar, Feyzi; Okur, Faik Fevzi; Ates, Mehmet


    Many complications have been reported after cardiopulmonary bypass. A common physiologic change during the early postoperative period after cardiopulmonary bypass is increased diuresis. In patients whose urine output is increased, postoperative diabetes insipidus can develop, although reports of this are rare. We present the cases of 2 patients who underwent on-pump coronary artery bypass grafting (with cardiopulmonary bypass). Each was diagnosed with diabetes insipidus postoperatively: a 54-year-old man on the 3rd day, and a 66-year-old man on the 4th day. Each patient recovered from the condition after 6 hours of intranasal therapy with synthetic vasopressin (antidiuretic hormone). The diagnosis of diabetes insipidus should be considered in patients who produce excessive urine early after cardiac surgery in which cardiopulmonary bypass has been used.

  8. Miller-Fisher syndrome after coronary artery bypass surgery. (United States)

    Aldag, Mustafa; Albeyoglu, Sebnem; Ciloglu, Ufuk; Kutlu, Hakan; Ceylan, Levent


    Miller-Fisher syndrome (MFS) is an uncommon neurological disorder that is considered a variant of the Guillain-Barre syndrome (GBS). It is clinically defined by a triad of symptoms, namely ataxia, areflexia and ophthalmoplegia. These acute inflammatory polyradiculopathic syndromes can be triggered by viral infections, major surgery, pregnancy or vaccination. While the overall incidence of GBS is 1.2-2.3 per 100 000 per year, MFS is a relatively rare disorder. Only six cases of GBS after cardiac surgery have been reported, and to our knowledge, we describe the first case of MFS after coronary artery bypass surgery. Although cardiac surgery with cardiopulmonary bypass may increase the incidence of MFS and GBS, the pathological mechanism is unclear. Cardiac surgery may be a trigger for the immune-mediated response and may cause devastating complications. It is also important to be alert to de novo autoimmune and unexpected neurological disorders such as MFS after coronary bypass surgery.

  9. Permeability, storage and hydraulic diffusivity controlled by earthquakes (United States)

    Brodsky, E. E.; Fulton, P. M.; Xue, L.


    Earthquakes can increase permeability in fractured rocks. In the farfield, such permeability increases are attributed to seismic waves and can last for months after the initial earthquake. Laboratory studies suggest that unclogging of fractures by the transient flow driven by seismic waves is a viable mechanism. These dynamic permeability increases may contribute to permeability enhancement in the seismic clouds accompanying hydraulic fracking. Permeability enhancement by seismic waves could potentially be engineered and the experiments suggest the process will be most effective at a preferred frequency. We have recently observed similar processes inside active fault zones after major earthquakes. A borehole observatory in the fault that generated the M9.0 2011 Tohoku earthquake reveals a sequence of temperature pulses during the secondary aftershock sequence of an M7.3 aftershock. The pulses are attributed to fluid advection by a flow through a zone of transiently increased permeability. Directly after the M7.3 earthquake, the newly damaged fault zone is highly susceptible to further permeability enhancement, but ultimately heals within a month and becomes no longer as sensitive. The observation suggests that the newly damaged fault zone is more prone to fluid pulsing than would be expected based on the long-term permeability structure. Even longer term healing is seen inside the fault zone of the 2008 M7.9 Wenchuan earthquake. The competition between damage and healing (or clogging and unclogging) results in dynamically controlled permeability, storage and hydraulic diffusivity. Recent measurements of in situ fault zone architecture at the 1-10 meter scale suggest that active fault zones often have hydraulic diffusivities near 10-2 m2/s. This uniformity is true even within the damage zone of the San Andreas fault where permeability and storage increases balance each other to achieve this value of diffusivity over a 400 m wide region. We speculate that fault zones

  10. Bypass materials in vascular surgery

    Directory of Open Access Journals (Sweden)

    Willich, Stephan N.


    Full Text Available Introduction: Arteriosclerotic changes can lead to circulatory disturbances in various areas of the human vascular system. In addition to pharmacological therapy and the management of risk factors (e. g. hypertension, diabetes, lipid metabolism disorders, and lifestyle, surgical interventions also play an important role in the treatment of arteriosclerosis. Long-segment arterial occlusions, in particular, can be treated successfully with bypass sur-gery. A number of different materials are available for this type of operation, such as autologous vein or pros-thetic grafts comprised of polytetrafluoroethylene (PTFE or Dacron®. Prosthetic materials are used especially in the treatment of peripheral artery disease, such as in aortoiliac or femoropopliteal bypass surgery. The present report will thus focus on this area in order to examine the effectiveness of different bypass materials. Among the efforts being made to refine the newly introduced DRG system in Germany, analysing the different bypass materials used in vascular surgery is particularly important. Indeed, in its current version the German DRG system does not distinguish between bypass materials in terms of reimbursement rates. Differences in cost structures are thus of especial interest to hospitals in their budget calculations, whereas both private and statutory health insurance funds are primarily interested in long-term results and their costs. Objectives: The goal of this HTA is to compare the different bypass materials used in vascular surgery in terms of their medical efficiency and cost-effectiveness, as well as with regard to their ethical, social and legal implications. In addition, this report aims to point out the areas in which further medical, epidemiological and health economic research is still needed. Methods: Relevant publications were identified by means of a structured search of databases accessed through the German Institute of Medical Documentation and Information

  11. Transverse permeability of woven fabrics

    NARCIS (Netherlands)

    Grouve, Wouter Johannes Bernardus; Akkerman, Remko; Loendersloot, Richard; van den Berg, S.


    The transverse permeability is an essential input in describing the consolidation process of CETEX® laminates. A two-dimensional, finite difference based, Stokes flow solver has been developed to determine the mesoscopic permeability of arbitrary fabric structures. The use of a multigrid solver

  12. Effects of Cardiopulmonary Bypass on Renal Perfusion, Filtration, and Oxygenation in Patients Undergoing Cardiac Surgery. (United States)

    Lannemyr, Lukas; Bragadottir, Gudrun; Krumbholz, Vitus; Redfors, Bengt; Sellgren, Johan; Ricksten, Sven-Erik


    Acute kidney injury is a common complication after cardiac surgery with cardiopulmonary bypass. The authors evaluated the effects of normothermic cardiopulmonary bypass on renal blood flow, glomerular filtration rate, renal oxygen consumption, and renal oxygen supply/demand relationship, i.e., renal oxygenation (primary outcome) in patients undergoing cardiac surgery. Eighteen patients with a normal preoperative serum creatinine undergoing cardiac surgery procedures with normothermic cardiopulmonary bypass (2.5 l · min · m) were included after informed consent. Systemic and renal hemodynamic variables were measured by pulmonary artery and renal vein catheters before, during, and after cardiopulmonary bypass. Arterial and renal vein blood samples were taken for measurements of renal oxygen delivery and consumption. Renal oxygenation was estimated from the renal oxygen extraction. Urinary N-acetyl-β-D-glucosaminidase was measured before, during, and after cardiopulmonary bypass. Cardiopulmonary bypass induced a renal vasoconstriction and redistribution of blood flow away from the kidneys, which in combination with hemodilution decreased renal oxygen delivery by 20%, while glomerular filtration rate and renal oxygen consumption were unchanged. Thus, renal oxygen extraction increased by 39 to 45%, indicating a renal oxygen supply/demand mismatch during cardiopulmonary bypass. After weaning from cardiopulmonary bypass, renal oxygenation was further impaired due to hemodilution and an increase in renal oxygen consumption, accompanied by a seven-fold increase in the urinary N-acetyl-β-D-glucosaminidase/creatinine ratio. Cardiopulmonary bypass impairs renal oxygenation due to renal vasoconstriction and hemodilution during and after cardiopulmonary bypass, accompanied by increased release of a tubular injury marker.

  13. Dabigatran abrogates brain endothelial cell permeability in response to thrombin. (United States)

    Hawkins, Brian Thomas; Gu, Yu-Huan; Izawa, Yoshikane; del Zoppo, Gregory John


    Atrial fibrillation (AF) increases the risk and severity of thromboembolic stroke. Generally, antithrombotic agents increase the hemorrhagic risk of thromboembolic stroke. However, significant reductions in thromboembolism and intracerebral hemorrhage have been shown with the antithrombin dabigatran compared with warfarin. As thrombin has been implicated in microvessel injury during cerebral ischemia, we hypothesized that dabigatran decreases the risk of intracerebral hemorrhage by direct inhibition of the thrombin-mediated increase in cerebral endothelial cell permeability. Primary murine brain endothelial cells (mBECs) were exposed to murine thrombin before measuring permeability to 4-kDa fluorescein isothiocyanate-dextran. Thrombin increased mBEC permeability in a concentration-dependent manner, without significant endothelial cell death. Pretreatment of mBECs with dabigatran completely abrogated the effect of thrombin on permeability. Neither the expressions of the endothelial cell β1-integrins nor the tight junction protein claudin-5 were affected by thrombin exposure. Oxygen-glucose deprivation (OGD) also increased permeability; this effect was abrogated by treatment with dabigatran, as was the additive effect of thrombin and OGD on permeability. Taken together, these results indicate that dabigatran could contribute to a lower risk of intracerebral hemorrhage during embolism-associated ischemia from AF by protection of the microvessel permeability barrier from local thrombin challenge.

  14. An apparent permeability model of shale gas under formation conditions (United States)

    Chen, Peng; Jiang, Shan; Chen, Yan; Wang, Shanshan


    There are various types of pores in shale, mainly consisting of nanopores and micropores, causing flow regime variations and apparent permeability changes during the development of the reservoir. In this paper, a Knudsen number calculation model is proposed with the actual conditions of gas in a shale reservoir. Then, based on the distribution of pores in shale, an apparent permeability model is established using hydrodynamics, and a calculation method is put forward for the actual permeability of a reservoir. Finally, the Knudsen number model and the permeability correction coefficient model are used to analyze the flow regime and permeability correction coefficients in pores during the development of the shale gas reservoir. Results show that with a decreasing of pressure, the Knudsen number increases, the flow regime changes from continuous flow and slip flow to transition flow or free molecular flow. When the Knudsen number is Kn > 0.1, and with a further increasing of Kn, gas molecule slippage greatly intensifies and the permeability correction coefficient K app/Kd significantly increases. While the Knudsen number increases, the permeability correction coefficient significantly increases in the micropores and the small pores, but this does not appear in the macropores and the mesopores. These results can be used to guide flow regime analysis and production forecasting in shale gas reservoirs.

  15. Permeability and permeability anisotropy in Crab Orchard sandstone: Experimental insights into spatio-temporal effects (United States)

    Gehne, Stephan; Benson, Philip M.


    Permeability in tight crustal rocks is primarily controlled by the connected porosity, shape and orientation of microcracks, the preferred orientation of cross-bedding, and sedimentary features such as layering. This leads to a significant permeability anisotropy. Less well studied, however, are the effects of time and stress recovery on the evolution of the permeability hysteresis which is becoming increasingly important in areas ranging from fluid migration in ore-forming processes to enhanced resource extraction. Here, we report new data simulating spatio-temporal permeability changes induced using effective pressure, simulating burial depth, on a tight sandstone (Crab Orchard). We find an initially (measured at 5 MPa) anisotropy of 2.5% in P-wave velocity and 180% in permeability anisotropy is significantly affected by the direction of the effective pressure change and cyclicity; anisotropy values decrease to 1% and 10% respectively after 3 cycles to 90 MPa and back. Furthermore, we measure a steadily increasing recovery time (10-20 min) for flow parallel to cross-bedding, and a far slower recovery time (20-50 min) for flow normal to cross-bedding. These data are interpreted via strain anisotropy and accommodation models, similar to the ;seasoning; process often used in dynamic reservoir extraction.

  16. Arrhythmias after coronary bypass surgery.


    Ormerod, O J; McGregor, C G; Stone, D L; Wisbey, C; Petch, M C


    Ninety patients undergoing coronary bypass surgery were studied prospectively by bedside and subsequent ambulatory electrocardiographic monitoring to investigate the incidence, possible causes, and prevention of atrial fibrillation. Patients with good left ventricular function were divided randomly into a control group or groups treated with digoxin or propranolol. In the control group the incidence of atrial fibrillation was 27% and of significant ventricular extrasystoles 3%. Propranolol re...

  17. POD analysis of laminar flow in a two-dimensional 180-degree sharp bend with bypass (United States)

    Chandramouli, Koushik; Arul Prakash, K.


    A Proper Orthogonal Decomposition analysis on laminar flow physics in a 180-degree sharp bend with bypass is demonstrated. The unsteadiness in the flow field observed downstream of thebend and the bypass is captured. The data for POD analysis has been obtained by solving mass, momentum and energy equations in Cartesian framework using Streamline Upwind/Petrov-Galerkin Finite element method. A parameter called IOR (Inlet to Outlet Ratio) is defined based on the inlet and outlet domain heights, with a bypass in the divider at 3 different locations. The fluid flow involves steady, periodic unsteady and chaotic unsteadiness and POD is conducted for the transient cases. The presence of the bypass increases the interaction of the vortices with the fluid from the bypass. The simulated results demonstrate the understanding of the vortices interaction with the walls and each other and thus the enhancement in the heat transfer.

  18. Rankine cycle condenser pressure control using an energy conversion device bypass valve (United States)

    Ernst, Timothy C; Nelson, Christopher R; Zigan, James A


    The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

  19. Cardiopulmonary bypass in the pediatric population. (United States)

    Whiting, David; Yuki, Koichi; DiNardo, James A


    Cardiopulmonary bypass (CPB) facilitates the repair of cardiac lesions in adults and children. Surgical mortality has decreased with improvements in technique allowing for the successful repair of complex heart defects in neonates of increasingly low body weight and gestational age. The physiological effects of CPB are more significant in children. The presence of intracardiac shunts and other anatomic variants further complicates CPB in patients with congenital heart disease. Special techniques and monitors are often necessary. Protocols are often established within individual institutions to standardize the approach to CPB. The anesthesiologist caring for the patient must understand the physiology of CPB to facilitate the initiation and separation from bypass, and to be able to treat complications. Evidence supporting a particular technique of CPB in pediatric population is still largely from uncontrolled or nonrandomized trials, observational studies, extrapolation from adult studies, and expert opinion. The heterogeneity of congenital heart disease makes randomized controlled trials or meta-analyses challenging, and thus they are limited in the literature. Copyright © 2015 Elsevier Ltd. All rights reserved.

  20. Plasma oxygen permeability may be a factor in atherosclerosis. (United States)

    Heppner, Bradley T; Morgan, Louis Wm


    Plasma oxygen permeability measures how easily oxygen dissolves in and diffuses through blood plasma. There has long been evidence that artery wall hypoxia plays a role in atherogenesis. This paper reviews the influence that plasma oxygen permeability has on artery wall oxygenation and presents experimental evidence for a relationship between plasma oxygen permeability and clinically significant obstructive coronary artery disease. Thirty-eight inpatients referred for diagnostic cardiac catheterization were scored for active coronary artery disease, and their plasma oxygen permeabilities were measured. There was a statistically significant (p = 0.04) correlation between active coronary artery disease and plasma oxygen permeability. There were also statistically significant differences in mean plasma oxygen permeability both between patients who did and did not have actively progressing coronary artery disease (p = 0.01) and between patients who did and did not have clinically significant obstructive coronary artery disease, whether it was actively progressing or not (p = 0.02). These findings suggest that a decline in plasma oxygen permeability may be one of the many factors associated with progression of atherosclerosis and that substances which increase oxygen permeability might offer a useful adjunct to current therapeutic measures.

  1. Off-pump versus on-pump coronary artery bypass grafting: Insights from the Arterial Revascularization Trial. (United States)

    Benedetto, Umberto; Altman, Douglas G; Gerry, Stephen; Gray, Alastair; Lees, Belinda; Flather, Marcus; Taggart, David P


    The long-term effects of off-pump coronary artery bypass continue to be controversial because some studies have reported increased adverse event rates with off-pump coronary artery bypass when compared with on-pump coronary artery bypass. The Arterial Revascularization Trial compared survival after bilateral versus single internal thoracic artery grafting. The choice of off-pump coronary artery bypass versus on-pump coronary artery bypass was based on the surgeon's discretion. We performed a post hoc analysis of the Arterial Revascularization Trial to compare 5-year outcomes with 2 strategies. Among 3102 patients enrolled in the Arterial Revascularization Trial, we selected 1260 patients who underwent off-pump coronary artery bypass versus 1700 patients who underwent on-pump coronary artery bypass with cardioplegic arrest for the present comparison. Primary outcomes were 5-year mortality and incidence of major cardiac and cerebrovascular events, including cardiovascular death, myocardial infarction, cerebrovascular accident, and revascularization after index procedure. Propensity score matching selected 1260 pairs for final comparison. Stratified Cox models were used for treatment effect estimate. Hospital mortality was comparable between off-pump coronary artery bypass and on-pump coronary artery bypass groups (12 [1.0%] vs 15 [1.2%]; P = .7). Conversion rate to on-pump during off-pump coronary artery bypass was 29 of 1260 (2.3%). When compared with off-pump coronary artery bypass not converted, off-pump coronary artery bypass converted to on-pump presented a remarkably higher hospital mortality (10.3% vs 0.7%; P pump coronary artery bypass and on-pump coronary artery bypass groups, respectively, with no significant difference (hazard ratio, 1.14; 95% confidence interval, 0.86-1.52; P = .35). Incidence of major cardiac and cerebrovascular events was 175 (14.3) versus 169 (13.8) in the off-pump coronary artery bypass and on-pump coronary artery bypass groups

  2. Cardiopulmonary bypass for pediatric cardiac surgery. (United States)

    Hirata, Yasutaka


    The management of cardiopulmonary bypass for pediatric cardiac surgery is more challenging than that in adults due to the smaller size, immaturity, and complexity of the anatomy in children. Despite major improvements in cardiopulmonary bypass, there remain many subjects of debate. This review article discusses the physiology of cardiopulmonary bypass for pediatric and congenital heart surgery, including topics related to hemodilution, hypothermia, acid-base strategies, inflammatory response, and myocardial protection.

  3. CO2 breakthrough pressure and permeability for unsaturated low-permeability sandstone of the Ordos Basin (United States)

    Zhao, Yan; Yu, Qingchun


    With rising threats from greenhouse gases, capture and injection of CO2 into suitable underground formations is being considered as a method to reduce anthropogenic emissions of CO2 to the atmosphere. As the injected CO2 will remain in storage for hundreds of years, the safety of CO2 geologic sequestration is a major concern. The low-permeability sandstone of the Ordos Basin in China is regarded as both caprock and reservoir rock, so understanding the breakthrough pressure and permeability of the rock is necessary. Because part of the pore volume experiences a non-wetting phase during the CO2 injection and migration process, the rock may be in an unsaturated condition. And if accidental leakage occurs, CO2 will migrate up into the unsaturated zone. In this study, breakthrough experiments were performed at various degrees of water saturation with five core samples of low-permeability sandstone obtained from the Ordos Basin. The experiments were conducted at 40 °C and pressures of >8 MPa to simulate the geological conditions for CO2 sequestration. The results indicate that the degree of water saturation and the pore structure are the main factors affecting the rock breakthrough pressure and permeability, since the influence of calcite dissolution and clay mineral swelling during the saturation process is excluded. Increasing the average pore radius or most probable pore radius leads to a reduction in the breakthrough pressure and an increase by several orders of magnitude in scCO2 effective permeability. In addition, the breakthrough pressure rises and the scCO2 effective permeability decreases when the water saturation increases. However, when the average pore radius is greater than 0.151 μm, the degree of water saturation will has a little effect on the breakthrough pressure. On this foundation, if the most probable pore radius of the core sample reaches 1.760 μm, the breakthrough pressure will not be impacted by the increasing water saturation. We establish

  4. Geothermal Permeability Enhancement - Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Joe Beall; Mark Walters


    The overall objective is to apply known permeability enhancement techniques to reduce the number of wells needed and demonstrate the applicability of the techniques to other undeveloped or under-developed fields. The Enhanced Geothermal System (EGS) concept presented in this project enhances energy extraction from reduced permeability zones in the super-heated, vapor-dominated Aidlin Field of the The Geysers geothermal reservoir. Numerous geothermal reservoirs worldwide, over a wide temperature range, contain zones of low permeability which limit the development potential and the efficient recovery of heat from these reservoirs. Low permeability results from poorly connected fractures or the lack of fractures. The Enhanced Geothermal System concept presented here expands these technologies by applying and evaluating them in a systematic, integrated program.

  5. A comparison of haemodynamics between subcranial-intracranial bypass and the traditional extracranial-intracranial bypass. (United States)

    Yu, Zaitao; Yang, Yang; Shi, Xiang'en; Qian, Hai; Liu, Fangjun


    Ischemic cerebrovascular diseases are traditionally treated using an extracranial-intracranial (EC-IC) bypass. The use of the internal maxillary artery (IMA) in the subcranial-intracranial (SC-IC) bypass was recently described as an alternative treatment. However, the haemodynamics of this new approach have not been defined. The haemodynamic parameters (flow volume [FV], internal diameter [ID], time-averaged mean velocity [TAM], pulsatility index [PI] and resistance index [RI]) of the IMA-radial artery graft (RAG)-middle cerebral artery (MCA) (n = 12) bypass and superficial temporal artery (STA)-MCA bypass (n = 18) were measured using intraoperative duplex ultrasonography and compared. The FV was 81.36 ± 30.41 (62.05-100.70) ml/min for the IMA-RAG-MCA bypass. This was significantly higher than that of the STA-MCA bypass (27.25 ± 9.32 (22.62-31.88) ml/min; P bypass were higher than in the STA-MCA bypass (P bypass and 94% for the STA-MCA bypass. The IMA-RAG-MCA bypass provides moderate to high blood flow to the revascularized territory and blood flow was higher by this method than the STA-MCA bypass.

  6. Permeability of soils in Mississippi (United States)

    O'Hara, Charles G.


    The permeability of soils in Mississippi was determined and mapped using a geographic information system (GIS). Soil permeabilities in Mississippi were determined to range in value from nearly 0.0 to values exceeding 5.0 inches per hour. The U.S. Soil Conservation Service's State Soil Geographic Data Base (STATSGO) was used as the primary source of data for the determination of area-weighted soil permeability. STATSGO provides soil layer properties that are spatially referenced to mapped areas. These mapped areas are referred to as polygons in the GIS. The polygons arc boundaries of soils mapped as a group and are given unique Map Unit Identifiers (MUIDs). The data describing the physical characteristics of the soils within each polygon are stored in a tabular data base format and are referred to as attributes. The U.S. Soil Conservation Service developed STATSGO to be primarily used as a guide for regional resource planning, management, and monitoring. STATSGO was designed so that soil information could be extracted from properties tables at the layer level, combined by component, and statistically expanded to cover the entire map unit. The results of this study provide a mapped value for permeability which is representative of the vertical permeability of soils in that area. The resultant permeability map provides a representative vertical soil permeability for a given area sufficient for county, multi- county, and area planning, and will be used as the soil permeability data component in the evaluation of the susceptibility of major aquifers to contami- nation in Mississippi.

  7. Permeability-porosity relationships in sedimentary rocks (United States)

    Nelson, Philip H.


    In many consolidated sandstone and carbonate formations, plots of core data show that the logarithm of permeability (k) is often linearly proportional to porosity (??). The slope, intercept, and degree of scatter of these log(k)-?? trends vary from formation to formation, and these variations are attributed to differences in initial grain size and sorting, diagenetic history, and compaction history. In unconsolidated sands, better sorting systematically increases both permeability and porosity. In sands and sandstones, an increase in gravel and coarse grain size content causes k to increase even while decreasing ??. Diagenetic minerals in the pore space of sandstones, such as cement and some clay types, tend to decrease log(k) proportionately as ?? decreases. Models to predict permeability from porosity and other measurable rock parameters fall into three classes based on either grain, surface area, or pore dimension considerations. (Models that directly incorporate well log measurements but have no particular theoretical underpinnings from a fourth class.) Grain-based models show permeability proportional to the square of grain size times porosity raised to (roughly) the fifth power, with grain sorting as an additional parameter. Surface-area models show permeability proportional to the inverse square of pore surface area times porosity raised to (roughly) the fourth power; measures of surface area include irreducible water saturation and nuclear magnetic resonance. Pore-dimension models show permeability proportional to the square of a pore dimension times porosity raised to a power of (roughly) two and produce curves of constant pore size that transgress the linear data trends on a log(k)-?? plot. The pore dimension is obtained from mercury injection measurements and is interpreted as the pore opening size of some interconnected fraction of the pore system. The linear log(k)-?? data trends cut the curves of constant pore size from the pore-dimension models

  8. Permeability theory and Palace Athena. (United States)

    Stamps, Arthur E


    Permeability theory suggests that safety in environments depends on how far and how easily one can perceive or move through environments. Parts of environments that limit perception or retard locomotion elicit impressions of being enclosed, so properties of environments that influence perceived enclosure are important in permeability theory. One prediction of permeability theory is that the more permeable the boundary, the less enclosed the region within that boundary will seem to be. Another prediction is that boundary depth will have little influence on perceived enclosure. These predictions were tested in the venue of Greek temples. 30 participants were tested (14 men, 16 women; M age = 40 yr.), who rated perceived enclosure for 18 stimuli. The stimuli were constructed using a virtual scene from the Tholos in Delphi with the positions of the columns forming the boundaries. The boundaries were designed to have different levels of permeability and depth. Data were analyzed in terms of effect sizes and focused comparisons. Results indicated that perceived enclosure was most strongly influenced by the visual permeability of the boundary, while depth of boundary had a much smaller effect on perceived enclosure.

  9. Impact of mineral fouling on hydraulic behavior of permeable reactive barriers. (United States)

    Lin, Li; Benson, Craig H; Lawson, Elizabeth M


    This paper describes reactive transport simulations conducted to assess the impact of mineral fouling on the hydraulic behavior of continuous-wall permeable reactive barriers (PRBs) employing granular zero-valent iron (ZVI) in carbonate-rich alluvial aquifers. The reactive transport model included a geochemical algorithm for simulating corrosion and mineral precipitation reactions that have been observed in ZVI PRBs. Results of simulations show that porosity and hydraulic conductivity of the ZVI decrease over time and that flows are redistributed throughout the PRB in response to fouling of the pore space. Under typical conditions, only subtle changes occur within the first 10 years (i.e., duration of the current field experience record with PRBs), and the most significant changes do not occur until the PRB has operated for at least 30 years. However, changes can occur sooner (or later) if the rate at which mineral-forming ions are delivered to the PRB is higher (or lower) than that expected under typical conditions (i.e., due to higher/lower flow rate or inflowing ground water that has higher/lower ionic strength). When the PRB is more permeable than the aquifer, the median Darcy flux in the PRB does not change appreciably over time because the aquifer controls the rate of flow through the PRB. However, seepage velocities in the PRB increase, and residence times decrease, due to porosity reductions caused by accumulation of minerals in the pore space. When fouling becomes extensive, bypassing and reductions in flow rate in the PRB occur.

  10. Reversible hyperinsulinemic hypoglycemia after gastric bypass: a consequence of altered nutrient delivery

    DEFF Research Database (Denmark)

    McLaughlin, Tracey; Peck, Marcia; Holst, Jens


    Severe hypoglycemia after Roux-en-Y gastric bypass surgery (RYGB) is an increasingly recognized condition, characterized by neuroglycopenia and inappropriately elevated insulin concentrations that occur primarily in the postprandial state. Both pathophysiology and treatment of this disorder remain...

  11. Coronary bypass grafting without use of cardiopulmonary bypass for dextrocardia. (United States)

    Mujanovic, Emir; Bergsland, Jacob; Tursic, Ademir; Stanimirovic-Mujanovic, Sanja; Kabil, Emir


    Dextrocardia is a condition in which the heart is pointed toward the right side of the chest instead of normally pointing to the left. The rate of atherosclerotic heart disease in subjects with this condition is similar to that of the general population. We present a patient with situs inversus totalis with dextrocardia who underwent coronary artery bypass grafting without use of cardiopulmonary bypass (OPCAB). A 74-year-old man who was known to have dextrocardia with situs inversus was admitted to the hospital because of angina. Coronary angiography was performed and showed ostial occlusion of the left anterior descendng artery (LAD) unsuitable for percutaneous coronary interventions but collatereralised from the right coronary artery. Patient underwent OPCAB under general anestesia. Right internal mammary artery was anastomosed to LAD on the beating heart with the surgeon standing on the right side of the patient. The patient's post-operative course was uneventful, and he was discharged on the 6th postoperative day in good condition. Performing OPCAB surgery is not technically more demanding, and present no unusual challenge on patients with dextrocardia.

  12. Cardiopulmonary bypass is associated with hemolysis and acute kidney injury in neonates, infants, and children*. (United States)

    Mamikonian, Lara S; Mamo, Lisa B; Smith, P Brian; Koo, Jeannie; Lodge, Andrew J; Turi, Jennifer L


    This pilot study assesses the degree of hemolysis induced by cardiopulmonary bypass and determines its association with acute kidney injury in pediatric patients. Further, it evaluates the degree to which the use of urinary biomarkers neutrophil gelatinase-associated lipocalin and cystatin C correlate with the presence of acute kidney injury and hemolysis following cardiopulmonary bypass. Prospective observational study. A 13-bed pediatric cardiac ICU in a university hospital. Children undergoing cardiac surgery with the use of cardiopulmonary bypass. None. Blood and urine samples were obtained at multiple time points before and after cardiopulmonary bypass. Hemolysis was assessed by measuring levels of plasma hemoglobin and haptoglobin. Acute kidney injury was defined as a doubling in serum creatinine from preoperative baseline and by using the pediatric-modified RIFLE criteria. Urinary neutrophil gelatinase-associated lipocalin and cystatin C levels were measured. A total of 40 patients (range, 3 d to 4.8 yr) were enrolled. Plasma hemoglobin levels increased markedly on separation from cardiopulmonary bypass with a concurrent decrease in haptoglobin. This was associated with an increase in protein oxidation in the plasma. Hemolysis was more evident in younger patients with a longer duration of bypass and in those requiring a blood-primed circuit. Forty percent of patients had a doubling in serum creatinine and acute kidney injury was developed in 88% of patients when defined by the pediatric-modified RIFLE criteria. Controlling for cardiopulmonary bypass time, persistently elevated levels of plasma hemoglobin were associated with a five-fold increase in acute kidney injury. Further, urinary neutrophil gelatinase-associated lipocalin measured 2 hours after separation from cardiopulmonary bypass was associated with acute kidney injury and with elevations in plasma hemoglobin. Cardiopulmonary bypass in pediatric patients results in significant hemolysis, which is

  13. Transient Diabetes Insipidus Following Cardiopulmonary Bypass. (United States)

    Ekim, Meral; Ekim, Hasan; Yilmaz, Yunus Keser; Bolat, Ali


    Diabetes insipidus (DI) results from inadequate output of Antidiuretic Hormone (ADH) from the pituitary gland (central DI) or the inability of the kidney tubules to respond to ADH (nephrogenic DI). ADH is an octapeptide produced in the supraoptic and paraventricular nuclei of the hypothalamus and stored in the posterior lobe of the pituitary gland. Cardiopulmonary Bypass (CPB) has been shown to cause a six-fold increased circulating ADH levels 12 hours after surgery. However, in some cases, ADH release may be transiently suppressed due to cardioplegia (cardiac standstill) or CPB leading to DI. We present the postoperative course of a 60-year-old man who developed transient DI after CPB. He was successfully treated by applying nasal desmopressin therapy. Relevant biochemical parameters should be monitored closely in patients who produce excessive urine after open heart surgery.

  14. Ultra by-pass ratio engine

    Energy Technology Data Exchange (ETDEWEB)

    Endo, Masanori; Sugiyama, Shichihisa


    A engine where ratio of fan's or propeller's air flow rate to air flow rate through engine combustion chamber is more than 15 is generally named the ultra bypass ratio engine (UBE). This engine employs the exhaust gas from the engine separately to the fan or propeller and jet nozzle exhaust to obtain higher total thrust efficiency. The increase rate of thrust by using UBE is equal to the improvement rate of fuel comsumption. Much efforts are continuously made to develop UBE toward the 21 century by many companies and it is necessary to develop the core engine of high specific output and high heat efficiency, and variable pitch / high aspect ratio fan or propeller and to reseach the integrated system technology. (5 refs, 9 figs)

  15. Blood-retinal barrier permeability versus diabetes duration and retinal morphology in insulin dependent diabetic patients

    DEFF Research Database (Denmark)

    Krogsaa, B; Lund-Andersen, H; Mehlsen, J


    The blood-retinal barrier permeability to fluorescein was quantitated in 54 patients (22 females and 32 males) with insulin dependent diabetes mellitus (IDDM) of different duration. Correlation was demonstrated between permeability and diabetes duration. A normal permeability was measured...... in patients with up to ten years diabetes duration. A pathologically increased permeability was measured with ten to 15 years diabetes duration and during the next decade the permeability increased rapidly to 5-10 times the normal value. Onset of diabetes in the decade before and after puberty did not change...... the pattern. However, the pathologically increased permeability after ten years duration of the disease could not be demonstrated in diabetics with onset of the disease after the age of 30 years. The permeability of the blood-retinal barrier correlated well with changes in retinal morphology as seen...

  16. The permeability of heterogeneous rocks (United States)

    Selvadurai, Patrick


    Darcy's original concept of permeability is largely associated with estimation of the hydraulic conductivity characteristics of isotropic and homogeneous porous media where the fluid flow characteristics can be estimated by appeal to a single scalar measure. Naturally occurring geomaterials are heterogeneous and the estimation of the effective permeability characteristics of such geomaterials presents a challenge not only in terms of the experimental procedures that should be used to ensure flow through the porous medium but also in the correct use of the theoretical concepts needed to accurately interpret the data. Relatively widely referred to rocks such as Indiana Limestone can exhibit spatial heterogeneity in the permeability characteristics even though the visual appearance can suggest the absence of such spatial and directional attributes (Selvadurai and Selvadurai, 2010). Argillaceous rocks such as the Cobourg Limestone found in southern Ontario, Canada can display hydraulic heterogeneity that is attributed to the presence of dolomitic and calcite nodular regions separated by calcite rock partings that contain an argillaceous component (Figure 1). Also, these rocks have extremely low permeability that requires the use of transient hydraulic pulse tests for the estimation of permeability. The performance of such pulse tests will be influenced by the bulk compressibility and bulk porosity of the porous skeleton consisting of the identifiable phases and their spatial distributions. The concepts of effective compressibilities and porosities therefore needs to be introduced if convenient procedures are to be developed for the accurate interpretation of even bench scale experiments (Selvadurai and Gɫowacki, 2017). The paper will describe both experimental and theoretical approaches for interpreting the effective Darcy permeability of the heterogeneous rocks using both experimental and computational approaches. In particular, the applicability of the "Geometric

  17. Strategies for optimisation of paediatric cardiopulmonary bypass

    NARCIS (Netherlands)

    Somer, Filip Maria Jan Jozef De


    The aim of this thesis is to address different aspects of paediatric cardiopulmonary bypass in detail and to propose modifications in order to reduce cardiopulmonary bypass related morbidity and by doing so, improve patient outcome. We will focus on four major items: (1) vascular access, (2) mass

  18. Cephalic veins in coronary artery bypass surgery

    DEFF Research Database (Denmark)

    Licht, P; Jakobsen, Erik; Lerbjerg, G


    Various alternative conduits for aortocoronary bypass grafting have been suggested when the saphenous vein quality is inadequate. During a 10-year period we have used the cephalic vein in 39 patients. Eighteen entered an angiographic follow-up study. A total of 31 arm vein grafts were used with 43...... bypass operations....

  19. Multimodality imaging of coronary artery bypass grafts

    NARCIS (Netherlands)

    Salm, Liesbeth Pauline


    This thesis describes multiple imaging modalities to examine coronary artery bypass grafts, and the research which was performed to further develop noninvasive imaging techniques to detect stenoses in native coronary arteries and bypass grafts in patients who experienced recurrent chest pain after

  20. Epicardial ultrasound in coronary artery bypass surgery

    NARCIS (Netherlands)

    Budde, R.P.J.


    Chapter 1 Coronary artery bypass surgery (CABG) is traditionally performed via a median sternotomy approach on cardiopulmonary bypass (arrested heart). Since the mid 1990ties, beating heart, minimally invasive and even totally endoscopic CABG are (re)explored. In all approaches to CABG, the

  1. Numerical and experimental investigation on labyrinth seal mechanism for bypass flow reduction in prismatic VHTR core

    Energy Technology Data Exchange (ETDEWEB)

    Yoon, Su-Jong, E-mail: [Department of Nuclear Engineering, Seoul National University, San 56-1, Daehak-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Lee, Jeong-Hun [Department of Nuclear Engineering, Seoul National University, San 56-1, Daehak-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of); Lee, Sang-Moon [Department of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Gu, Incheon 402-751 (Korea, Republic of); Tak, Nam-il; Kim, Min-Hwan [Korea Atomic Energy Research Institute, 150-1 Deokjin-Dong, 1045 Daedeokdaero, Yuseong, Daejeon 305-353 (Korea, Republic of); Kim, Kwang-Yong [Department of Mechanical Engineering, Inha University, 253 Yonghyun-Dong, Nam-Gu, Incheon 402-751 (Korea, Republic of); Park, Goon-Cherl [Department of Nuclear Engineering, Seoul National University, San 56-1, Daehak-Dong, Kwanak-Gu, Seoul 151-742 (Korea, Republic of)


    Highlights: • Bypass flow reduction method was developed by applying labyrinth seal mechanism. • Grooves on side walls of replaceable reflector block were made. • Design of the grooved wall of the reflector block was optimized by the RSA method. • The flow resistance of the bypass gap rose from 18.04 to 26.24 by the optimization. • The bypass ratios at the inlet and outlet were reduced by 36.19% and 14.66%, respectively. -- Abstract: Core bypass flow in block type very high temperature reactor (VHTR) occurs due to the inevitable gaps between the hexagonal core blocks for the block installation and refueling. Since the core bypass flow affects the reactor safety and efficiency, it should be minimized to enhance the core thermal margin. In this regard, the core bypass flow reduction method applying the labyrinth seal mechanism was developed and optimized by using the single-objective shape optimization method. Response surface approximation (RSA) method was adopted as the optimization method. Side wall of the replaceable reflector block was redesigned and response surface approximate model was adopted to optimize the shape of the reflector wall. Computational fluid dynamics (CFD) analyses were carried out not only to assess the limitation of existing method of bypass flow reduction, but also to optimize the design of a newly developed reduction method. The experiment with Seoul National University (SNU) multi-block experimental facility was performed to demonstrate the performance of the reduction method. It was found that the effect of the existing bypass flow reduction method by sealing the bypass gap exit was restricted nearby the lower region of the core. However, the flow resistance factor of the bypass gap increased from 18.04 to 26.24 by the optimized reduction method. The results of the performance test showed that the bypass flow distribution was reduced throughout the entire core regions. The bypass flow ratios at the inlet and the outlet were

  2. Permeability of WIPP Salt During Damage Evolution and Healing

    Energy Technology Data Exchange (ETDEWEB)



    The presence of damage in the form of microcracks can increase the permeability of salt. In this paper, an analytical formulation of the permeability of damaged rock salt is presented for both initially intact and porous conditions. The analysis shows that permeability is related to the connected (i.e., gas accessible) volumetric strain and porosity according to two different power-laws, which may be summed to give the overall behavior of a porous salt with damage. This relationship was incorporated into a constitutive model, known as the Multimechanism Deformation Coupled Fracture (MDCF) model, which has been formulated to describe the inelastic flow behavior of rock salt due to coupled creep, damage, and healing. The extended model was used to calculate the permeability of rock salt from the Waste Isolation Pilot Plant (WIPP) site under conditions where damage evolved with stress over a time period. Permeability changes resulting from both damage development under deviatoric stresses and damage healing under hydrostatic pressures were considered. The calculated results were compared against experimental data from the literature, which indicated that permeability in damaged intact WIPP salt depends on the magnitude of the gas accessible volumetric strain and not on the total volumetric strain. Consequently, the permeability of WIPP salt is significantly affected by the kinetics of crack closure, but shows little dependence on the kinetics of crack removal by sintering.

  3. Diagenetic effect on permeabilities of geothermal sandstone reservoirs

    DEFF Research Database (Denmark)

    Weibel, Rikke; Olivarius, Mette; Kristensen, Lars

    The Danish subsurface contains abundant sedimentary deposits, which can be utilized for geothermal heating. The Upper Triassic – Lower Jurassic continental-marine sandstones of the Gassum Formation has been utilised as a geothermal reservoir for the Thisted Geothermal Plant since 1984 extracting...... and permeability is caused by increased diagenetic changes of the sandstones due to increased burial depth and temperatures. Therefore, the highest water temperatures typically correspond with the lowest porosities and permeabilities. Especially the permeability is crucial for the performance of the geothermal......-line fractures. Continuous thin chlorite coatings results in less porosity- and permeability-reduction with burial than the general reduction with burial, unless carbonate cemented. Therefore, localities of sandstones characterized by these continuous chlorite coatings may represent fine geothermal reservoirs...

  4. Water permeability is a measure of severity in acute appendicitis. (United States)

    Pini, Nicola; Pfeifle, Viktoria A; Kym, Urs; Keck, Simone; Galati, Virginie; Holland-Cunz, Stefan; Gros, Stephanie J


    Acute appendicitis is the most common indication for pediatric abdominal emergency surgery. Determination of the severity of appendicitis on clinical grounds is challenging. Complicated appendicitis presenting with perforation, abscess or diffuse peritonitis is not uncommon. The question remains why and when acute appendicitis progresses to perforation. The aim of this study was to assess the impact of water permeability on the severity of appendicitis. We show that AQP1 expression and water permeability in appendicitis correlate with the stage of inflammation and systemic infection parameters, leading eventually to perforation of the appendix. AQP1 is also expressed within the ganglia of the enteric nervous system and ganglia count increases with inflammation. Severity of appendicitis can be correlated with water permeability measured by AQP1 protein expression and increase of ganglia count in a progressive manner. This introduces the question if regulation of water permeability can present novel curative or ameliorating therapeutic options.

  5. Regulation of AQP0 water permeability is enhanced by cooperativity. (United States)

    Németh-Cahalan, Karin L; Clemens, Daniel M; Hall, James E


    Aquaporin 0 (AQP0), essential for lens clarity, is a tetrameric protein composed of four identical monomers, each of which has its own water pore. The water permeability of AQP0 expressed in Xenopus laevis oocytes can be approximately doubled by changes in calcium concentration or pH. Although each monomer pore functions as a water channel, under certain conditions the pores act cooperatively. In other words, the tetramer is the functional unit. In this paper, we show that changes in external pH and calcium can induce an increase in water permeability that exhibits either a positive cooperativity switch-like increase in water permeability or an increase in water permeability in which each monomer acts independently and additively. Because the concentrations of calcium and hydrogen ions increase toward the center of the lens, a concentration signal could trigger a regulatory change in AQP0 water permeability. It thus seems plausible that the cooperative modes of water permeability regulation by AQP0 tetramers mediated by decreased pH and elevated calcium are the physiologically important ones in the living lens.

  6. Measurement of hepatic insulin sensitivity early after the bypass of the proximal small bowel in humans. (United States)

    Miras, A D; Herring, R; Vusirikala, A; Shojaee-Moradi, F; Jackson, N C; Chandaria, S; Jackson, S N; Goldstone, A P; Hakim, N; Patel, A G; Umpleby, A M; Le Roux, C W


    Unlike gastric banding or sleeve gastrectomy procedures, intestinal bypass procedures, Roux-en-Y gastric bypass in particular, lead to rapid improvements in glycaemia early after surgery. The bypass of the proximal small bowel may have weight loss and even caloric restriction-independent glucose-lowering properties on hepatic insulin sensitivity. In this first human mechanistic study, we examined this hypothesis by investigating the early effects of the duodeno-jejunal bypass liner (DJBL; GI Dynamics, USA) on the hepatic insulin sensitivity by using the gold standard euglycaemic hyperinsulinaemic clamp methodology. Seven patients with obesity underwent measurement of hepatic insulin sensitivity at baseline, 1 week after a low-calorie liquid diet and after a further 1 week following insertion of the DJBL whilst on the same diet. Duodeno-jejunal bypass liner did not improve the insulin sensitivity of hepatic glucose production beyond the improvements achieved with caloric restriction. Caloric restriction may be the predominant driver of early increases in hepatic insulin sensitivity after the endoscopic bypass of the proximal small bowel. The same mechanism may be at play after Roux-en-Y gastric bypass and explain, at least in part, the rapid improvements in glycaemia.

  7. Shoulder arthroplasty following gastric bypass, do complications follow? (United States)

    Schoch, Bradley S; Aibinder, William R; Werthel, Jean-David; Sperling, John W; Sanchez-Sotelo, Joaquin; Cofield, Robert H


    Previous reports have shown an increased risk of complications after arthroplasty in the obese population. It remains unclear if gastric bypass surgery prior to shoulder arthroplasty modifies the complication and failure rate. The purpose of this study is to assess the complication and re-operation rates following shoulder arthroplasty in this population. Between 2002 and 2012, 39 shoulders with prior gastric bypass underwent shoulder arthroplasty (3 HA, 16 TSA, 20 RSA). The mean time from the gastric bypass to arthroplasty was 13 years (range, 0.7-32). Shoulders were followed for a minimum of two years (mean, 3.8 years) or until re-operation. Outcome measures included pain, range of motion, satisfaction, modified Neer ratings, and ASES scores. Complications occurred in seven shoulders (18%), with five requiring re-operation. There was no common failure mechanism. Re-operations occurred for aseptic glenoid loosening, periprosthetic fracture, and unexplained pain. Those shoulders with complications were similar to those without in regard to age, sex, and BMI. Complications were more common following anatomic arthroplasty compared to reverse arthroplasty (5 vs 1, p = 0.06); however, complications were not improved compared to historical controls with morbid obesity. Overall, pain improved significantly from 4.8 pre-operatively to 2.3 postoperatively (p bypass surgery prior to shoulder arthroplasty leads to clinical improvement in both pain and range of motion. Prior gastric bypass surgery does not result in a lower surgical complication rate compared to previously published reports in the morbidly obese population. Level 4, case series.

  8. Validation of viscoelastic coagulation tests during cardiopulmonary bypass. (United States)

    Ortmann, E; Rubino, A; Altemimi, B; Collier, T; Besser, M W; Klein, A A


    Viscoelastic point-of-care tests such as thromboelastography (TEG) and rotational thromboelastometry (ROTEM) are increasingly used to guide hemostatic therapy after cardiac surgery. The aim of this study was to assess their clinical utility during cardiopulmonary bypass to predict postbypass coagulation status and to guide therapy. In this prospective study, TEG and ROTEM tests were performed in 52 adult patients undergoing elective cardiac surgery at two time points: near the end of cardiopulmonary bypass and after heparin reversal with protamine. The 95% confidence intervals of the mean difference were compared with a prespecified clinically relevant limit of ± 20% of the value after protamine. Both viscoelastic fibrinogen assays were well within the prespecified clinically relevant limit (≥ 79% of patients). The laboratory Clauss fibrinogen was much lower during cardiopulmonary bypass than after protamine (mean difference 1.2 g L(-1) , 95% CI 1.03-1.4, which was outside a clinically acceptable difference. For intrinsically activated tests, clotting times (CT) were different and outside the prespecified limit on TEG (mean difference -1.2 min, 95% CI -1.8 to -0.6) but not on ROTEM (mean difference 2.3 sec, 95% CI -8.6 to 13.2), while clot strength was well within the clinical limit on both devices (≥ 94% of patients). For extrinsically activated tests, clot strength on both TEG and ROTEM was within the pre-specified limit in 98% of patients. Results from TEG and ROTEM tests performed toward the end of cardiopulmonary bypass are similar to results after reversal of heparin. Amplitudes indicating clot strength were the most stable parameters across all tests, whereas CT showed more variability. In contrast, laboratory testing of fibrinogen using the Clauss assay was essentially invalid during cardiopulmonary bypass. © 2015 International Society on Thrombosis and Haemostasis.

  9. Monitoring Single-channel Water Permeability in Polarized Cells*


    Erokhova, Liudmila; Horner, Andreas; K?gler, Philipp; Pohl, Peter


    So far the determination of unitary permeability (pf ) of water channels that are expressed in polarized cells is subject to large errors because the opening of a single water channel does not noticeably increase the water permeability of a membrane patch above the background. That is, in contrast to the patch clamp technique, where the single ion channel conductance may be derived from a single experiment, two experiments separated in time and/or space are required to obtain the single-chann...

  10. Use of DMPC and DSPC lipids for verapamil and naproxen permeability studies by PAMPA. (United States)

    Alvarez-Figueroa, M J; Contreras-Garrido, B C; Soto-Arriaza, M A


    Verapamil and naproxen Parallel Artificial Membrane Permeability Assay (PAMPA) permeability was studied using lipids not yet reported for this model in order to facilitate the quantification of drug permeability. These lipids are 1,2-distearoyl-sn-glycero-3-phosphatidylcholine (DSPC), 1,2-dimyristoyl-sn-glycero-3-phosphocholine (DMPC) and an equimolar mixture of DMPC/DSPC, both in the absence and in the presence of 33.3 mol% of cholesterol. PAMPA drug permeability using the lipids mentioned above was compared with lecithin-PC. The results show that verapamil permeability depends on the kind of lipid used, in the order DMPC > DMPC/DSPC > DSPC. The permeability of the drugs was between 1.3 and 3.5-times larger than those obtained in lecithin-PC for all the concentrations of the drug used. Naproxen shows similar permeability than verapamil; however, the permeability increased with respect to lecithin-PC only when DMPC and DMPC/DSPC were used. This behavior could be explained by a difference between the drug net charge at pH 7.4. On the other hand, in the presence of cholesterol, verapamil permeability increases in all lipid systems; however, the relative verapamil permeability respect to lecithin-PC did not show any significant increase. This result is likely due to the promoting effect of cholesterol, which is not able to compensate for the large increase in verapamil permeability observed in lecithin-PC. With respect to naproxen, its permeability value and relative permeability respect lecithin-PC not always increased in the presence of cholesterol. This result is probably attributed to the negative charge of naproxen rather than its molecular weight. The lipid systems studied have an advantage in drug permeability quantification, which is mainly related to the charge of the molecule and not to its molecular weight or to cholesterol used as an absorption promoter.

  11. Changes in permeability caused by transient stresses: field observations, experiments, and mechanisms (United States)

    Manga, Michael; Beresnev, Igor; Brodsky, Emily E.; Elkhoury, Jean E.; Elsworth, Derek; Ingebritsen, Steve E.; Mays, David C.; Wang, Chi-Yuen


    Oscillations in stress, such as those created by earthquakes, can increase permeability and fluid mobility in geologic media. In natural systems, strain amplitudes as small as 10–6 can increase discharge in streams and springs, change the water level in wells, and enhance production from petroleum reservoirs. Enhanced permeability typically recovers to prestimulated values over a period of months to years. Mechanisms that can change permeability at such small stresses include unblocking pores, either by breaking up permeability-limiting colloidal deposits or by mobilizing droplets and bubbles trapped in pores by capillary forces. The recovery time over which permeability returns to the prestimulated value is governed by the time to reblock pores, or for geochemical processes to seal pores. Monitoring permeability in geothermal systems where there is abundant seismicity, and the response of flow to local and regional earthquakes, would help test some of the proposed mechanisms and identify controls on permeability and its evolution.

  12. Utilising cardiopulmonary bypass for cancer surgery. Malignancy-induced protein C deficiency and thrombophilia.

    LENUS (Irish Health Repository)

    Marshall, C


    Cardiopulmonary bypass has evolved over the last 30 years. It is an important tool for the cardiac surgeon today and also has applications in non-cardiac operations such as surgery to extract tumours. Such patients undergoing surgery for cancer may be at an increased risk of a thromboembolic event post surgery, due to disturbances in the normal clotting pathway leading to hypercoagulability. One such disturbance is malignancy-induced Protein C deficiency. A deficiency of Protein C can cause hypercoagulabitity. Recent studies have examined cardiopulmonary bypass and inherited Protein C deficiency. However, surgery for cancer patients with a malignancy-induced Protein C deficiency involving cardiopulmonary bypass has not been reported. Surgery using CPB in these patients may result in increased morbidity and mortality. The objective of this article is to review the literature in order to discuss the occurrence, the aetiology and possible management of cancer patients with malignancy-induced Protein C deficiencies that require cardiopulmonary bypass for their surgery.

  13. The Impact of Lung Ventilation on Some Cytokines after Coronary Artery Bypass Grafting. (United States)

    Toikkanen, V; Rinne, T; Nieminen, R; Moilanen, E; Laurikka, J; Porkkala, H; Tarkka, M; Mennander, A


    Cardiopulmonary bypass induces a systematic inflammatory response, which is partly understood by investigation of peripheral blood cytokine levels alone; the lungs may interfere with the net cytokine concentration. We investigated whether lung ventilation influences lung passage of some cytokines after coronary artery bypass grafting. In total, 47 patients undergoing coronary artery bypass grafting were enrolled, and 37 were randomized according to the ventilation technique: (1) No-ventilation group, with intubation tube detached from the ventilator; (2) low tidal volume group, with continuous low tidal volume ventilation; and (3) continuous 10 cm H2O positive airway pressure. Ten selected patients undergoing surgery without cardiopulmonary bypass served as a referral group. Representative pulmonary and radial artery blood samples were collected for the evaluation of calculated lung passage (pulmonary/radial artery) of the pro-inflammatory cytokines (interleukin 6 and interleukin 8) and the anti-inflammatory interleukin 10 immediately after induction of anesthesia (T1), 1 h after restoring ventilation/return of flow in all grafts (T2), and 20 h after restoring ventilation/return of flow in all grafts (T3). Pulmonary/radial artery interleukin 6 and pulmonary/radial artery interleukin 8 ratios ( p = 0.001 and p = 0.05, respectively) decreased, while pulmonary/radial artery interleukin 10 ratio ( p = 0.001) increased in patients without cardiopulmonary bypass as compared with patients with cardiopulmonary bypass. The pulmonary/radial artery equation is an innovative means for the evaluation of cytokine lung passage after coronary artery bypass grafting. The mode of lung ventilation has no impact on some cytokines after coronary artery bypass grafting in patients treated with cardiopulmonary bypass.

  14. Bypassing birthing centres for child birth: a community-based study in rural Chitwan Nepal

    Directory of Open Access Journals (Sweden)

    Rajani Shah


    Full Text Available Abstract Background Child delivery in a health facility is important to reduce maternal mortality. Bypassing nearby birthing facility to deliver at a hospital is common in developing countries including Nepal. Very little is known about the extent and determinants of bypassing the birthing centres in Nepal. This study measures the status of bypassing, characteristics of bypassers and their reasons for bypassing. Methods A community-based cross-sectional study was carried out in six rural village development committees of Chitwan district of Nepal. Structured interviews were conducted with 263 mothers who had given birth at a health facility and whose nearest facility was a birthing centre. Descriptive statistics, univariate and multivariable logistic regression analysis were performed. Results More than half of the mothers had bypassed the nearer birthing centres to deliver at hospital. Living in plain area [aOR: 2.467; 95 % CI: 1.005–6.058], higher wealth index [aOR: 4.981; 95 % CI: 2.482–9.999], advantaged caste/ethnicity [aOR: 2.172; 95 % CI: 1.153–4.089], older age [aOR: 2.222; 95 % CI: 1.050–4.703] and first birth [aOR: 2.032; 95 % CI: 1.060–3.894] were associated with higher likelihood of bypassing. Among the reasons of bypassing as reported by the bypassers, lack of operation, video x-ray, and blood test facilities were the most common ones, followed by the lack of medicines/drugs and equipment, lack of skilled service provider, and inadequate physical facilities, among others. Conclusions Quality of service at the birthing centres needs to be given a high consideration to increase their use as well as to ensure an equitable access to the quality care by all.

  15. Perturbation of the microvascular glycocalyx and perfusion in infants after cardiopulmonary bypass. (United States)

    Nussbaum, Claudia; Haberer, Amelie; Tiefenthaller, Anna; Januszewska, Katarzyna; Chappell, Daniel; Brettner, Florian; Mayer, Peter; Dalla Pozza, Robert; Genzel-Boroviczény, Orsolya


    Perturbation of the endothelial glycocalyx is discussed in the pathogenesis of complications related to cardiopulmonary bypass. We evaluated the effects of cardiopulmonary bypass on the microcirculation and the microvascular endothelial glycocalyx of infants undergoing surgery for congenital cardiac defects. The microcirculation was visualized at the ear conch using Sidestream dark field imaging before surgery (T0), after admission to the intensive care unit (T1), 24 hours postsurgery (T2), and 7 days postsurgery (T3). Glycocalyx thickness was assessed by measurement of the perfused boundary region. Microcirculatory parameters included total and perfused vessel density, vessel diameters, and microcirculatory flow index. A total of 40 infants undergoing cardiac surgery (36 with cardiopulmonary bypass, 4 without cardiopulmonary bypass) were examined. As controls, measurements before and after cardiac catheterization (n = 6) and before and after surgery for cleft palate (n = 9) were performed. After surgery with cardiopulmonary bypass, the perfused boundary region was significantly increased, indicating reduced glycocalyx thickness at T1 compared with preoperative values with a stepwise return to baseline by T3. In the control groups, no significant perfused boundary region changes were noted. Furthermore, after cardiopulmonary bypass, a transient, significant reduction of the microcirculatory flow index and the perfused vessel density was seen at T1. Similar changes were observed after cardiac surgery without cardiopulmonary bypass, but not in the other controls. Our study reveals for the first time local perturbations of the endothelial glycocalyx and microvascular perfusion in infants after surgery with cardiopulmonary bypass. Microcirculatory monitoring might be a useful tool to evaluate interventions aiming at reduction of bypass-related complications. Copyright © 2015 The American Association for Thoracic Surgery. Published by Elsevier Inc. All rights reserved.

  16. Small intestinal permeability in dermatological disease. (United States)

    Hamilton, I; Fairris, G M; Rothwell, J; Cunliffe, W J; Dixon, M F; Axon, A T


    Passive small intestinal permeability was investigated in 62 patients with atopic eczema, 29 with psoriasis and 18 with dermatitis herpetiformis, using the cellobiose/mannitol differential sugar absorption test. Urinary recovery of cellobiose and mannitol in patients with both psoriasis and eczema were similar to values in a control population, and were not affected by the extent or activity of skin disease. The cellobiose/mannitol recovery ratio was abnormally high in seven patients with eczema, six of whom underwent jejunal biopsy. Jejunal mucosal morphology was normal in five, and one patient was found to have coeliac disease. Cellobiose/mannitol recovery ratio was also abnormal in seven patients with psoriasis, and in 11 with dermatitis herpetiformis, seven of whom had a normal jejunal biopsy. These findings demonstrate that the passive permeability of the small intestine is normal in the majority of patients with atopic eczema and psoriasis. Increased absorption of macromolecules from the gut lumen cannot be ascribed to defective intestinal integrity, and is unlikely to be relevant to the pathogenesis of eczema. Abnormal intestinal permeability may be a more sensitive manifestation of gluten-sensitive enteropathy than jejunal biopsy in dermatitis herpetiformis.


    Black, S. H.; Gerhardt, Philipp


    Black, S. H. (The University of Michigan, Ann Arbor) and Philipp Gerhardt. Permeability of bacterial spores. I. Characterization of glucose uptake. J. Bacteriol. 82:743–749. 1961.—The total uptake of glucose by masses of clean, dormant spores was measured to assess their permeability. After correction for intercellular space, packed spores of Bacillus cereus strain terminalis were found in 87 determinations to be permeated by glucose to 40% of their weight. The glucose uptake was relatively independent of environmental variables, and thus was concluded to occur principally through a process of passive diffusion. PMID:13869665

  18. Endocannabinoids modulate human blood–brain barrier permeability in vitro (United States)

    Hind, William H; Tufarelli, Cristina; Neophytou, Maria; Anderson, Susan I; England, Timothy J; O'Sullivan, Saoirse E


    Background and Purpose Endocannabinoids alter permeability at various epithelial barriers, and cannabinoid receptors and endocannabinoid levels are elevated by stroke, with potential neuroprotective effects. We therefore explored the role of endocannabinoids in modulating blood–brain barrier (BBB) permeability in normal conditions and in an ischaemia/reperfusion model. Experimental Approach Human brain microvascular endothelial cell and astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance. Endocannabinoids or endocannabinoid-like compounds were assessed for their ability to modulate baseline permeability or OGD-induced hyperpermeability. Target sites of action were investigated using receptor antagonists and subsequently identified with real-time PCR. Key Results Anandamide (10 μM) and oleoylethanolamide (OEA, 10 μM) decreased BBB permeability (i.e. increased resistance). This was mediated by cannabinoid CB2 receptors, transient receptor potential vanilloid 1 (TRPV1) channels, calcitonin gene-regulated peptide (CGRP) receptor (anandamide only) and PPARα (OEA only). Application of OEA, palmitoylethanolamide (both PPARα mediated) or virodhamine (all 10 μM) decreased the OGD-induced increase in permeability during reperfusion. 2-Arachidonoyl glycerol, noladin ether and oleamide did not affect BBB permeability in normal or OGD conditions. N-arachidonoyl-dopamine increased permeability through a cytotoxic mechanism. PPARα and γ, CB1 receptors, TRPV1 channels and CGRP receptors were expressed in both cell types, but mRNA for CB2 receptors was only present in astrocytes. Conclusion and Implication The endocannabinoids may play an important modulatory role in normal BBB physiology, and also afford protection to the BBB during ischaemic stroke, through a number of target sites. PMID:25651941

  19. Endocannabinoids modulate human blood-brain barrier permeability in vitro. (United States)

    Hind, William H; Tufarelli, Cristina; Neophytou, Maria; Anderson, Susan I; England, Timothy J; O'Sullivan, Saoirse E


    Endocannabinoids alter permeability at various epithelial barriers, and cannabinoid receptors and endocannabinoid levels are elevated by stroke, with potential neuroprotective effects. We therefore explored the role of endocannabinoids in modulating blood-brain barrier (BBB) permeability in normal conditions and in an ischaemia/reperfusion model. Human brain microvascular endothelial cell and astrocyte co-cultures modelled the BBB. Ischaemia was modelled by oxygen-glucose deprivation (OGD) and permeability was measured by transepithelial electrical resistance. Endocannabinoids or endocannabinoid-like compounds were assessed for their ability to modulate baseline permeability or OGD-induced hyperpermeability. Target sites of action were investigated using receptor antagonists and subsequently identified with real-time PCR. Anandamide (10 μM) and oleoylethanolamide (OEA, 10 μM) decreased BBB permeability (i.e. increased resistance). This was mediated by cannabinoid CB2 receptors, transient receptor potential vanilloid 1 (TRPV1) channels, calcitonin gene-regulated peptide (CGRP) receptor (anandamide only) and PPARα (OEA only). Application of OEA, palmitoylethanolamide (both PPARα mediated) or virodhamine (all 10 μM) decreased the OGD-induced increase in permeability during reperfusion. 2-Arachidonoyl glycerol, noladin ether and oleamide did not affect BBB permeability in normal or OGD conditions. N-arachidonoyl-dopamine increased permeability through a cytotoxic mechanism. PPARα and γ, CB1 receptors, TRPV1 channels and CGRP receptors were expressed in both cell types, but mRNA for CB2 receptors was only present in astrocytes. The endocannabinoids may play an important modulatory role in normal BBB physiology, and also afford protection to the BBB during ischaemic stroke, through a number of target sites. © 2015 The Authors. British Journal of Pharmacology published by John Wiley & Sons Ltd on behalf of The British Pharmacological Society.

  20. Study on Surface Permeability of Concrete under Immersion

    Directory of Open Access Journals (Sweden)

    Jun Liu


    Full Text Available In this paper, concrete specimens are immersed in ultrapure water, to study the evolutions of surface permeability, pore structure and paste microstructure following the prolonging of immersion period. According to the results, after 30-day immersion, the surface permeability of concrete becomes higher as compared with the value before immersion. However, further immersion makes the surface permeability decrease, so that the value measured after 150-day immersion is only half that measured after 30-day immersion. The early increase in surface permeability should be mainly attributed to the leaching of calcium hydroxide, while the later decrease to the refinement of pore structure due to hydration. The two effects work simultaneously and compete throughout the immersion period. The proposed mechanisms get support from microscopic measurements and observations.

  1. Amorphous azithromycin with improved aqueous solubility and intestinal membrane permeability. (United States)

    Aucamp, Marique; Odendaal, Roelf; Liebenberg, Wilna; Hamman, Josias


    Azithromycin (AZM) is a poorly soluble macrolide antibacterial agent. Its low solubility is considered as the major contributing factor to its relatively low oral bioavailability. The aim of this study was to improve the solubility of this active pharmaceutical ingredient (API) by preparing an amorphous form by quench cooling of the melt and to study the influence of the improved solubility on membrane permeability. The amorphous azithromycin (AZM-A) exhibited a significant increase in water solubility when compared to the crystalline azithromycin dihydrate (AZM-DH). The influence that the improved solubility could have on membrane permeability was also studied. The apparent permeability coefficient (Papp) values of AZM-A were statistically significantly higher (p solubility of AZM in the amorphous form also produced improved permeability across excised intestinal tissue at physiological pH values found in the small intestine.

  2. Coronary arteries bypass grafting stenosis

    Directory of Open Access Journals (Sweden)

    Mahmoud Ebrahimi


    Full Text Available Coronary artery disease (CAD is a major global problem. In addition, it is higher risk of mortality for women more than men are when develop in female gender Atherosclerotic plaques consist of deposits of fatty material in the tunica intima. The role of inflammatory process in CAD has been known from 1980’s. Several studies investigated the innate immunity and adaptive immunity roles in atherosclerosis and they concluded that it plays a key role in atherosclerosis. Coronary artery bypass grafting (CABG is a widely used method for the treatment of CAD. Based on the literature, CABG is the most common surgical operation done worldwide. In During the first 10 years after CABG, up to 50% of saphenous grafts will occlude. Graft restenosis is beginning with acute thrombosis, intima hyperplasia, and plaque formation. In this review, some molecular pathways of graft failure and restenosis such as apoptosis and nuclear factor kappa B (NF-ĸB are described.

  3. Cardiopulmonary Bypass and Oxidative Stress (United States)

    Zakkar, Mustafa; Guida, Gustavo; Suleiman, M-Saadeh; Angelini, Gianni D.


    The development of the cardiopulmonary bypass (CPB) revolutionized cardiac surgery and contributed immensely to improved patients outcomes. CPB is associated with the activation of different coagulation, proinflammatory, survival cascades and altered redox state. Haemolysis, ischaemia, and perfusion injury and neutrophils activation during CPB play a pivotal role in oxidative stress and the associated activation of proinflammatory and proapoptotic signalling pathways which can affect the function and recovery of multiple organs such as the myocardium, lungs, and kidneys and influence clinical outcomes. The administration of agents with antioxidant properties during surgery either intravenously or in the cardioplegia solution may reduce ROS burst and oxidative stress during CPB. Alternatively, the use of modified circuits such as minibypass can modify both proinflammatory responses and oxidative stress. PMID:25722792

  4. Simulating gas-water relative permeabilities for nanoscale porous media with interfacial effects

    Directory of Open Access Journals (Sweden)

    Wang Jiulong


    Full Text Available This paper presents a theoretical method to simulate gas-water relative permeability for nanoscale porous media utilizing fractal theory. The comparison between the calculation results and experimental data was performed to validate the present model. The result shows that the gas-water relative permeability would be underestimated significantly without interfacial effects. The thinner the liquid film thickness, the greater the liquid-phase relative permeability. In addition, both liquid surface diffusion and gas diffusion coefficient can promote gas-liquid two-phase flow. Increase of liquid surface diffusion prefer to increase liquid-phase permeability obviously as similar as increase of gas diffusion coefficient to increase gas-phase permeability. Moreover, the pore structure will become complicated with the increase of fractal dimension, which would reduce the gas-water relative permeability. This study has provided new insights for development of gas reservoirs with nanoscale pores such as shale.

  5. 21 CFR 870.4205 - Cardiopulmonary bypass bubble detector. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass bubble detector. 870.4205... bypass bubble detector. (a) Identification. A cardiopulmonary bypass bubble detector is a device used to detect bubbles in the arterial return line of the cardiopulmonary bypass circuit. (b) Classification...

  6. 21 CFR 870.4380 - Cardiopulmonary bypass pump speed control. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump speed control. 870... Cardiopulmonary bypass pump speed control. (a) Identification. A cardiopulmonary bypass pump speed control is a... control the speed of blood pumps used in cardiopulmonary bypass surgery. (b) Classification. Class II...

  7. 21 CFR 870.4390 - Cardiopulmonary bypass pump tubing. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pump tubing. 870.4390... bypass pump tubing. (a) Identification. A cardiopulmonary bypass pump tubing is polymeric tubing which is... through the cardiopulmonary bypass circuit. (b) Classification. Class II (performance standards). ...

  8. 21 CFR 870.4200 - Cardiopulmonary bypass accessory equipment. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass accessory equipment. 870... Cardiopulmonary bypass accessory equipment. (a) Identification. Cardiopulmonary bypass accessory equipment is a device that has no contact with blood and that is used in the cardiopulmonary bypass circuit to support...

  9. 21 CFR 870.4420 - Cardiopulmonary bypass cardiotomy return sucker. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass cardiotomy return sucker... Cardiopulmonary bypass cardiotomy return sucker. (a) Identification. A cardiopulmonary bypass cardiotomy return... from the chest or heart during cardiopulmonary bypass surgery. (b) Classification. Class II...

  10. 21 CFR 870.4350 - Cardiopulmonary bypass oxygenator. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass oxygenator. 870.4350... bypass oxygenator. (a) Identification. A cardiopulmonary bypass oxygenator is a device used to exchange... the FDA guidance document entitled “Guidance for Cardiopulmonary Bypass Oxygenators 510(k) Submissions...

  11. 21 CFR 870.4310 - Cardiopulmonary bypass coronary pressure gauge. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass coronary pressure gauge... Cardiopulmonary bypass coronary pressure gauge. (a) Identification. A cardiopulmonary bypass coronary pressure gauge is a device used in cardiopulmonary bypass surgery to measure the pressure of the blood perfusing...

  12. 21 CFR 870.4320 - Cardiopulmonary bypass pulsatile flow generator. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass pulsatile flow generator... Cardiopulmonary bypass pulsatile flow generator. (a) Identification. A cardiopulmonary bypass pulsatile flow... device is placed in a cardiopulmonary bypass circuit downstream from the oxygenator. (b) Classification...

  13. Elevated fasting and postprandial C-terminal telopeptide after Roux-en-Y gastric bypass. (United States)

    Maghsoodi, Negar; Alaghband-Zadeh, Jamshid; Cross, Gemma F; Werling, Malin; Fändriks, Lars; Docherty, Neil G; Olbers, Torsten; Dew, Tracy; Sherwood, Roy A; Vincent, Royce P; le Roux, Carel W


    Background Roux-en-Y gastric bypass increases circulating bile acid concentrations, known mediators of postprandial suppression of markers of bone resorption. Long-term data, however, indicate that Roux-en-Y gastric bypass confers an increased risk of bone loss on recipients. Methods Thirty-six obese individuals, median age 44 (26-64) with median body mass index at baseline of 42.5 (40.4-46) were studied before and 15 months after Roux-en-Y gastric bypass. After an overnight fast, patients received a 400 kcal mixed meal. Blood samples were collected premeal then at 30-min periods for 120 min. Pre and postmeal samples were analysed for total bile acids, parathyroid hormone and C-terminal telopeptide. Results Body weight loss post Roux-en-Y gastric bypass was associated with a median 4.9-fold increase in peak postprandial total bile acid concentration, and a median 2.4-fold increase in cumulative food evoked bile acid response. Median fasting parathyroid hormone, postprandial reduction in parathyroid hormone and total parathyroid hormone release over 120 min remained unchanged after surgery. After surgery, median fasting C-terminal telopeptide increased 2.3-fold, peak postprandial concentrations increased 3.8-fold and total release was increased 1.9-fold. Conclusions Fasting and postprandial total bile acids and C-terminal telopeptide are increased above reference range after Roux-en-Y gastric bypass. These changes occur in spite of improved vitamin D status with supplementation. These results suggest that post-Roux-en-Y gastric bypass increases in total bile acids do not effectively oppose an ongoing resorptive signal operative along the gut-bone axis. Serial measurement of C-terminal telopeptide may be of value as a risk marker for long-term skeletal pathology in patients post Roux-en-Y gastric bypass.

  14. Experimental Investigation of Wave Velocity-Permeability Model for Granite Subjected to Different Temperature Processing

    Directory of Open Access Journals (Sweden)

    Guanghui Jiang


    Full Text Available Understanding the change of permeability of rocks before and after heating is of great significance for exploitation of hydrocarbon resources and disposal of nuclear waste. The rock permeability under high temperature cannot be measured with most of the existing methods. In this paper, quality, wave velocity, and permeability of granite specimen from Maluanshan tunnel are measured after high temperature processing. Quality and wave velocity of granite decrease and permeability of granite increases with increasing temperature. Using porosity as the medium, a new wave velocity-permeability model is established with modified wave velocity-porosity formula and Kozeny-Carman formula. Under some given wave velocities and corresponding permeabilities through experiment, the permeabilities at different temperatures and wave velocities can be obtained. By comparing the experimental and the theoretical results, the proposed formulas are verified. In addition, a sensitivity analysis is performed to examine the effect of particle size, wave velocities in rock matrix, and pore fluid on permeability: permeability increases with increasing particle size, wave velocities in rock matrix, and pore fluid; the higher the rock wave velocity, the lower the effect of wave velocities in rock matrix and pore fluid on permeability.

  15. Off-Pump Versus On-Pump Coronary Artery Bypass Grafting

    DEFF Research Database (Denmark)

    Møller, Christian H; Steinbrüchel, Daniel A


    Coronary artery bypass grafting (CABG) remains the preferred treatment in patients with complex coronary artery disease. However, whether the procedure should be performed with or without the use of cardiopulmonary bypass, referred to as off-pump and on-pump CABG, is still up for debate....... Intuitively, avoidance of cardiopulmonary bypass seems beneficial as the systemic inflammatory response from extracorporeal circulation is omitted, but no single randomized trial has been able to prove off-pump CABG superior to on-pump CABG as regards the hard outcomes death, stroke or myocardial infarction....... In contrast, off-pump CABG is technically more challenging and may be associated with increased risk of incomplete revascularization. The purpose of the review is to summarize the current literature comparing outcomes of off-pump versus on-pump coronary artery bypass surgery....


    Directory of Open Access Journals (Sweden)

    S. I. Suskov


    Full Text Available The basic variants of cytokines reactions defining type of organ dysfunctions are revealed in the course of car- diopulmonary bypass and in the early postoperative period. Their character and expression, depends on gravity preoperative an immunodeficiency and initial degree of heart insufficiency. Diphasic dynamics of development of system inflammatory reaction is confirmed after cardiopulmonary bypass: increase of levels proinflammatory cytokines is in the first phase and anti-inflammatory cytokines with development immunodepression and cellular anergy in is the second phase. Also, key role IL-1Ra is revealed in restraint of hyperactivation of system inflam- matory reaction. Blood whey levels IL-6, IL-8, G-CSF, TNF-α and IL-1Ra should be defined to cardiopulmonary bypass, in 10–12 hours, 24 hours and 3 days after cardiopulmonary bypass and may be used as prognostic criteria of development of postoperative complications. 

  17. Exhaust gas bypass valve control for thermoelectric generator (United States)

    Reynolds, Michael G; Yang, Jihui; Meisner, Greogry P.; Stabler, Francis R.; De Bock, Hendrik Pieter Jacobus; Anderson, Todd Alan


    A method of controlling engine exhaust flow through at least one of an exhaust bypass and a thermoelectric device via a bypass valve is provided. The method includes: determining a mass flow of exhaust exiting an engine; determining a desired exhaust pressure based on the mass flow of exhaust; comparing the desired exhaust pressure to a determined exhaust pressure; and determining a bypass valve control value based on the comparing, wherein the bypass valve control value is used to control the bypass valve.

  18. Outer membrane permeability of Acinetobacter calcoaceticus mediates susceptibility to rat polymorphonuclear leukocyte granule contents.


    Loeffelholz, M J; Modrzakowski, M C


    Growth of Acinetobacter calcoaceticus on specific alkanes altered the outer membrane permeability of the organism, as indicated by a change in sensitivity to the antibiotic actinomycin D. As the carbon length of the alkane energy source decreased, outer membrane permeability and susceptibility to actinomycin D increased. Concomitant with the increase in outer membrane permeability, A. calcoaceticus became more susceptible to the oxygen-independent antimicrobial activity of extracted contents ...

  19. Pattern and predictors of dual antiplatelet use after coronary artery bypass graft surgery. (United States)

    Mori, Makoto; Shioda, Kayoko; Yun, James J; Mangi, Abeel A; Darr, Umer; Geirsson, Arnar


    Resumption of dual antiplatelet therapy after coronary artery bypass grafting in patients presenting with acute coronary syndrome is recommended, but the current practice pattern in the United States remains unknown. We aimed to investigate the current pattern of dual antiplatelet therapy use after coronary artery bypass grafting at the Yale-New Haven Hospital. We conducted a single-center retrospective review of patients who presented with acute coronary syndrome and underwent coronary artery bypass grafting between 2014 and 2016. The primary outcome was hospital discharge with dual antiplatelet therapy. Mixed-effect multivariate logistic regression was used to evaluate predictors of dual antiplatelet therapy use or nonuse, accounting for surgeon-specific preference. The discriminatory ability of the model was evaluated with receiver operating characteristics analysis. Of 572 patients included, only 29% were discharged with dual antiplatelet therapy. In the mixed-effect multivariate model isolating surgeon preferences, increase in age (odds ratio, 0.95; 95% confidence interval, 0.92-0.98; P bypass grafting compared with on-pump coronary artery bypass grafting was associated with increased odds of dual antiplatelet therapy use (odds ratio, 31.5; 95% confidence interval, 12.8-77.2; P bypass grafting was low and variable among surgeons. The use or nonuse was guided by previously established risk factors of recurrent ischemia and bleeding, along with surgeon preference. Published by Elsevier Inc.

  20. Environmental impact case study : Martinsville bypass. (United States)


    At the request of the Environmental Quality Division, the Environmental and Economics Section of the Virginia Highway Research Council conducted an environmental impact study of the proposed Route 220 bypass around Martinsville. This evaluation of th...

  1. Beach protection by a system of permeable groins (United States)

    Boczar-Karakiewicz, B.; Romanczyk, W.; Roy, N.


    A new type of permeable groin (called System of Groins Maltec-Savard - SGMS) has been installed at three eroded sites located in the coastal area on the north shore of the St. Lawrence, Quebec, Canada. In this area, the narrow sandy beaches with sandy or sand-silty cliff of variable height (10-15~m) are exposed to obliquely incident waves arriving from both west (summer) and east (autumn), and to tidal currents (maximum tidal rate is 4.3~m). The periods of summer waves equal 3-5~s, with wave heights of about 0.4-0.7~m. In the autumn, major storm waves reach periods of up to 7-10~s, with wave heights of 1.0-1.2~m. The new groins are sediment traps formed by a central double and permeable groin with several smaller lateral, groins installed on one or both sides of the central groin (Boczar-Karakiewicz et al., 2001). The permeable central and lateral groins are structured by inserting double ranges of wooden piles (diameter of about 10 cm). The space between the ranges of piles (some 0.8~m wide) is filled with tree branches (e.g., the top parts of pine trees, a waste product of the local forest industry). A permeable grid covering the top of the groins forms a cage that holds the branches in place. The lateral groins, are identical but much shorter than the central groin. The whole system dissipates the incident energy of wave- and tidally-generated currents and causes accretion of sand transported by these currents. The GSMS also allows the by-pass of some sediment to adjacent zones without groins. Observations and results of measurements from three experiments field show that: (1) a sandy beach in front of a coastal cliff secures its stability and attenuates the erosion caused by waves and tidal currents; (2) permeability and flexibility of the SGMS causes the accretion of sediment in the protected area without erosion in the neighboring zones; (3) the SGMS does not generate wave reflection and any secondary current; (4) the materials of the groins are easily

  2. Effects of cardiopulmonary bypass on propofol pharmacokinetics and bispectral index during coronary surgery

    Directory of Open Access Journals (Sweden)

    Ricardo Antonio G. Barbosa


    Full Text Available PURPOSE: Cardiopulmonary bypass is known to alter propofol pharmacokinetics in patients undergoing cardiac surgery. However, few studies have evaluated the impact of these alterations on postoperative pharmacodynamics. This study was designed to test the hypothesis that changes in propofol pharmacokinetics increase hypnotic effects after cardiopulmonary bypass. METHODS: Twenty patients scheduled for on-pump coronary artery bypass graft (group, n=10 or off-pump coronary artery bypass graft (group, n=10 coronary artery bypass grafts were anesthetized with sufentanil and a propofol target controlled infusion (2.0 µg/mL. Depth of hypnosis was monitored using the bispectral index. Blood samples were collected from the induction of anesthesia up to 12 hours after the end of propofol infusion, at predetermined intervals. Plasma propofol concentrations were measured using high-performance liquid chromatography, followed by a non-compartmental propofol pharmacokinetic analysis. Data were analyzed using ANOVA, considering p<0.05 as significant. RESULTS: After cardiopulmonary bypass, despite similar plasma propofol concentrations in both groups, bispectral index values were lower in the on-pump coronary artery bypass graft group. Time to extubation after the end of propofol infusion was greater in the on-pump coronary artery bypass graft group (334 ± 117 vs. 216 ± 85 min, p = 0.04. Patients undergoing cardiopulmonary bypass had shorter biological (1.82 ± 0.5 vs. 3.67 ± 1.15h, p < 0.01 and terminal elimination (6.27 ± 1.29 vs. 10.5h ± 2.18, p < 0.01 half-life values, as well as higher total plasma clearance (28.36 ± 11.40 vs.18.29 ± 7.67 mL/kg/min, p = 0.03, compared to patients in the off-pump coronary artery bypass graft group. CONCLUSION: Aside from the increased sensitivity of the brain to anesthetics after cardiopulmonary bypass, changes in propofol pharmacokinetics may contribute to its central nervous system effects.

  3. Bypass diode for a solar cell (United States)

    Rim, Seung Bum [Palo Alto, CA; Kim, Taeseok [San Jose, CA; Smith, David D [Campbell, CA; Cousins, Peter J [Menlo Park, CA


    Bypass diodes for solar cells are described. In one embodiment, a bypass diode for a solar cell includes a substrate of the solar cell. A first conductive region is disposed above the substrate, the first conductive region of a first conductivity type. A second conductive region is disposed on the first conductive region, the second conductive region of a second conductivity type opposite the first conductivity type.

  4. [Plasma ionized magnesium concentration following cardiopulmonary bypass]. (United States)

    Amaya, Fumimasa; Fukui, Michihiko; Tsuruta, Hiroshi; Kooguchi, Kunihiko; Shimosato, Goshun


    We performed a retrospective study to analyze plasma ionized magnesium concentration following cardiopulmonary bypass. Severe decrease of ionized magnesium concentration associated with frequent abnormal ECG sign was found in a patient with magnesium-free cardioplegia. Cardioplegia containing 16 mmol.l-1 of magnesium ion maintained ionized magnesium concentration within normal ranges without postoperative magnesium loading. Use of cardioplegia containing magnesium or adequate magnesium supplement is thought to be essential for patients receiving cardiopulmonary bypass.

  5. Monsanto may bypass NIH in microbe test. (United States)

    Sun, Marjorie


    The Monsanto Company is planning to ask the Environmental Protection Agency for clearance to field test a genetically engineered microbial pesticide, bypassing the traditional approval process of the National Institutes of Health. Although only federally funded institutions are required to obtain NIH approval for genetic engineering tests, Monsanto is the first company to bypass the NIH regulatory process, which has become mired in a lawsuit brought by Jeremy Rifkin.

  6. Breast cancer biomarkers predict weight loss after gastric bypass surgery

    Directory of Open Access Journals (Sweden)

    Sauter Edward R


    Full Text Available Abstract Background Obesity has long been associated with postmenopausal breast cancer risk and more recently with premenopausal breast cancer risk. We previously observed that nipple aspirate fluid (n levels of prostate specific antigen (PSA were associated with obesity. Serum (s levels of adiponectin are lower in women with higher body mass index (BMI and with breast cancer. We conducted a prospective study of obese women who underwent gastric bypass surgery to determine: 1 change in n- and s-adiponectin and nPSA after surgery and 2 if biomarker change is related to change in BMI. Samples (30-s, 28-n and BMI were obtained from women 0, 3, 6 and 12 months after surgery. Findings There was a significant increase after surgery in pre- but not postmenopausal women at all time points in s-adiponectin and at 3 and 6 months in n-adiponectin. Low n-PSA and high s-adiponectin values were highly correlated with decrease in BMI from baseline. Conclusions Adiponectin increases locally in the breast and systemically in premenopausal women after gastric bypass. s-adiponectin in pre- and nPSA in postmenopausal women correlated with greater weight loss. This study provides preliminary evidence for biologic markers to predict weight loss after gastric bypass surgery.

  7. Quantifying Evaporation in a Permeable Pavement System (United States)

    Studies quantifying evaporation from permeable pavement systems are limited to a few laboratory studies and one field application. This research quantifies evaporation for a larger-scale field application by measuring the water balance from lined permeable pavement sections. Th...

  8. Permeable Pavement Research - Edison, New Jersey (United States)

    This presentation provides the background and summary of results collected at the permeable pavement parking lot monitored at the EPA facility in Edison, NJ. This parking lot is surfaced with permeable interlocking concrete pavers (PICP), pervious concrete, and porous asphalt. ...

  9. [Simplified laparoscopic gastric bypass. Initial experience]. (United States)

    Hernández-Miguelena, Luis; Maldonado-Vázquez, Angélica; Cortes-Romano, Pablo; Ríos-Cruz, Daniel; Marín-Domínguez, Raúl; Castillo-González, Armando


    Obesity surgery includes various gastrointestinal procedures. Roux-en-Y gastric bypass is the prototype of mixed procedures being the most practiced worldwide. A similar and novel technique has been adopted by Dr. Almino Cardoso Ramos and Dr. Manoel Galvao called "simplified bypass," which has been accepted due to the greater ease and very similar results to the conventional technique. The aim of this study is to describe the results of the simplified gastric bypass for treatment of morbid obesity in our institution. We performed a descriptive, retrospective study of all patients undergoing simplified gastric bypass from January 2008 to July 2012 in the obesity clinic of a private hospital in Mexico City. A total of 90 patients diagnosed with morbid obesity underwent simplified gastric bypass. Complications occurred in 10% of patients; these were more frequent bleeding and internal hernia. Mortality in the study period was 0%. The average weight loss at 12 months was 72.7%. Simplified gastric bypass surgery is safe with good mid-term results and a loss of adequate weight in 71% of cases.

  10. Cell-Free Plasma Hemoglobin and Male Gender Are Risk Factors for Acute Kidney Injury in Low Risk Children Undergoing Cardiopulmonary Bypass. (United States)

    Kim-Campbell, Nahmah; Gretchen, Catherine; Callaway, Clifton; Felmet, Kathryn; Kochanek, Patrick M; Maul, Timothy; Wearden, Peter; Sharma, Mahesh; Viegas, Melita; Munoz, Ricardo; Gladwin, Mark T; Bayir, Hülya


    To determine the relationship between the production of cell-free plasma hemoglobin and acute kidney injury in infants and children undergoing cardiopulmonary bypass for cardiac surgery. Prospective observational study. Twelve-bed cardiac ICU in a university-affiliated children's hospital. Children were prospectively enrolled during their preoperative outpatient appointment with the following criteria: greater than 1 month to less than 18 years old, procedures requiring cardiopulmonary bypass, no preexisting renal dysfunction. None. Plasma and urine were collected at baseline (in a subset), the beginning and end of cardiopulmonary bypass, and 2 hours and 24 hours after cardiopulmonary bypass in 60 subjects. Levels of plasma hemoglobin increased during cardiopulmonary bypass and were associated (p bypass duration (R = 0.22), depletion of haptoglobin at end and 24 hours after cardiopulmonary bypass (R = 0.12 and 0.15, respectively), lactate dehydrogenase levels at end cardiopulmonary bypass (R = 0.27), and change in creatinine (R = 0.12). Forty-three percent of patients developed acute kidney injury. There was an association between plasma hemoglobin level and change in creatinine that varied by age (overall [R = 0.12; p 2 yr [R = 0.22; p bypass and male gender are associated with subsequent renal dysfunction in low-risk pediatric patients, especially in those older than 2 years. Further studies are needed to determine whether specific subgroups of pediatric patients undergoing cardiopulmonary bypass would benefit from potential treatments for hemolysis and plasma hemoglobin-associated renal dysfunction.

  11. Two-Year Changes in Bone Density After Roux-en-Y Gastric Bypass Surgery (United States)

    Bouxsein, Mary L.; Putman, Melissa S.; Monis, Elizabeth L.; Roy, Adam E.; Pratt, Janey S. A.; Butsch, W. Scott; Finkelstein, Joel S.


    Context: Bariatric surgery is increasingly popular but may lead to metabolic bone disease. Objective: The objective was to determine the rate of bone loss in the 24 months after Roux-en-Y gastric bypass. Design and Setting: This was a prospective cohort study conducted at an academic medical center. Participants: The participants were adults with severe obesity, including 30 adults undergoing gastric bypass and 20 nonsurgical controls. Outcomes: We measured bone mineral density (BMD) at the lumbar spine and proximal femur by quantitative computed tomography (QCT) and dual-energy x-ray absorptiometry at 0, 12, and 24 months. BMD and bone microarchitecture were also assessed by high-resolution peripheral QCT, and estimated bone strength was calculated using microfinite element analysis. Results: Weight loss plateaued 6 months after gastric bypass but remained greater than controls at 24 months (−37 ± 3 vs −5 ± 3 kg [ mean ± SEM]; P bypass compared with nonsurgical controls, as assessed by QCT and dual-energy x-ray absorptiometry (P bypass. Cortical and trabecular BMD and microarchitecture at the distal radius and tibia deteriorated in the gastric bypass group throughout the 24 months, such that estimated bone strength was 9% lower than controls. The decline in BMD persisted beyond the first year, with rates of bone loss exceeding controls throughout the second year at all skeletal sites. Mean serum calcium, 25(OH)-vitamin D, and PTH were maintained within the normal range in both groups. Conclusions: Substantial bone loss occurs throughout the 24 months after gastric bypass despite weight stability in the second year. Although the benefits of gastric bypass surgery are well established, the potential for adverse effects on skeletal integrity remains an important concern. PMID:25646793

  12. Implantation of transcatheter aortic valve prosthesis through the ascending aorta concomitant with coronary artery bypass grafting without cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    João Carlos Ferreira Leal


    Full Text Available Introdution: The transcatheter aortic valve implantation in the treatment of high-risk symptomatic aortic stenosis has increased the number of implants every year. The learning curve for transcatheter aortic valve implantation has improved since the last 12 years, allowing access alternatives. Objective: The aim of this study is to approach the implantation of transcatheter aortic valve through transaortic via associated with off-pump cardiopulmonary bypass surgery in a 67-year-old man, with chronic obstructive pulmonary disease, arterial hypertension and kidney transplant. Methods: Off-pump coronary artery bypass surgery was performed and the valve in the aortic position was released successfully. Results: There were no complications in the intraoperative and postoperative period. Gradient reduction, effective orifice increasing of the prosthesis and absence of valvular regurgitation after implantation were observed by transesophageal echocardiography. Conclusion: Procedural success demonstrates that implantation of transcatheter aortic valve through the ascending aorta associated with coronary artery bypass surgery without CPB is a new option for these patients.

  13. Impact of Postoperative Hypothermia on Outcomes in Coronary Artery Bypass Surgery Patients. (United States)

    Yu, Pey-Jen; Cassiere, Hugh A; Kohn, Nina; Mattia, Allan; Hartman, Alan R


    To determine the impact of postoperative hypothermia on outcomes in coronary artery bypass graft surgery (CABG) patients. A retrospective study was performed on patients who underwent isolated CABG between 2011 and 2014. Single-center study at a university hospital. All patients who underwent isolated CABG with cardiopulmonary bypass between 2011 and 2014. Patients underwent isolated CABG on cardiopulmonary bypass. Patients were propensity-score matched based on the likelihood of being hypothermic (bypass, and had longer cardiopulmonary bypass runs compared with the normothermic group. Of the 748 patients who were propensity matched, there were no differences in blood and blood product transfusion requirements, mortality and complication rates, time on the ventilator, length of ICU stay, and length of hospital stay between hypothermic and normothermic patients. Hypothermia at ICU admission after CABG was not associated with increased adverse outcomes, possibly suggesting that complete rewarming before separation from cardiopulmonary bypass may not be essential in all patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Regulation of intestinal permeability: The role of proteases. (United States)

    Van Spaendonk, Hanne; Ceuleers, Hannah; Witters, Leonie; Patteet, Eveline; Joossens, Jurgen; Augustyns, Koen; Lambeir, Anne-Marie; De Meester, Ingrid; De Man, Joris G; De Winter, Benedicte Y


    The gastrointestinal barrier is - with approximately 400 m 2 - the human body's largest surface separating the external environment from the internal milieu. This barrier serves a dual function: permitting the absorption of nutrients, water and electrolytes on the one hand, while limiting host contact with noxious luminal antigens on the other hand. To maintain this selective barrier, junction protein complexes seal the intercellular space between adjacent epithelial cells and regulate the paracellular transport. Increased intestinal permeability is associated with and suggested as a player in the pathophysiology of various gastrointestinal and extra-intestinal diseases such as inflammatory bowel disease, celiac disease and type 1 diabetes. The gastrointestinal tract is exposed to high levels of endogenous and exogenous proteases, both in the lumen and in the mucosa. There is increasing evidence to suggest that a dysregulation of the protease/antiprotease balance in the gut contributes to epithelial damage and increased permeability. Excessive proteolysis leads to direct cleavage of intercellular junction proteins, or to opening of the junction proteins via activation of protease activated receptors. In addition, proteases regulate the activity and availability of cytokines and growth factors, which are also known modulators of intestinal permeability. This review aims at outlining the mechanisms by which proteases alter the intestinal permeability. More knowledge on the role of proteases in mucosal homeostasis and gastrointestinal barrier function will definitely contribute to the identification of new therapeutic targets for permeability-related diseases.

  15. Thermodynamic Cycle Analysis of Magnetohydrodynamic-Bypass Airbreathing Hypersonic Engines (United States)

    Litchford, Ron J.; Bityurin, Valentine A.; Lineberry, John T.


    Established analyses of conventional ramjet/scramjet performance characteristics indicate that a considerable decrease in efficiency can be expected at off-design flight conditions. This can be explained, in large part, by the deterioration of intake mass flow and limited inlet compression at low flight speeds and by the onset of thrust degradation effects associated with increased burner entry temperature at high flight speeds. In combination, these effects tend to impose lower and upper Mach number limits for practical flight. It has been noted, however, that Magnetohydrodynamic (MHD) energy management techniques represent a possible means for extending the flight Mach number envelope of conventional engines. By transferring enthalpy between different stages of the engine cycle, it appears that the onset of thrust degradation may be delayed to higher flight speeds. Obviously, the introduction of additional process inefficiencies is inevitable with this approach, but it is believed that these losses are more than compensated through optimization of the combustion process. The fundamental idea is to use MHD energy conversion processes to extract and bypass a portion of the intake kinetic energy around the burner. We refer to this general class of propulsion system as an MHD-bypass engine. In this paper, we quantitatively assess the performance potential and scientific feasibility of MHD-bypass airbreathing hypersonic engines using ideal gasdynamics and fundamental thermodynamic principles.

  16. Thermodynamic Cycle Analysis of Magnetohydrodynamic-Bypass Hypersonic Airbreathing Engines (United States)

    Litchford, R. J.; Cole, J. W.; Bityurin, V. A.; Lineberry, J. T.


    The prospects for realizing a magnetohydrodynamic (MHD) bypass hypersonic airbreathing engine are examined from the standpoint of fundamental thermodynamic feasibility. The MHD-bypass engine, first proposed as part of the Russian AJAX vehicle concept, is based on the idea of redistributing energy between various stages of the propulsion system flow train. The system uses an MHD generator to extract a portion of the aerodynamic heating energy from the inlet and an MHD accelerator to reintroduce this power as kinetic energy in the exhaust stream. In this way, the combustor entrance Mach number can be limited to a specified value even as the flight Mach number increases. Thus, the fuel and air can be efficiently mixed and burned within a practical combustor length, and the flight Mach number operating envelope can be extended. In this paper, we quantitatively assess the performance potential and scientific feasibility of MHD-bypass engines using a simplified thermodynamic analysis. This cycle analysis, based on a thermally and calorically perfect gas, incorporates a coupled MHD generator-accelerator system and accounts for aerodynamic losses and thermodynamic process efficiencies in the various engin components. It is found that the flight Mach number range can be significantly extended; however, overall performance is hampered by non-isentropic losses in the MHD devices.

  17. Flow Simulation of Supersonic Inlet with Bypass Annular Duct (United States)

    Kim, HyoungJin; Kumano, Takayasu; Liou, Meng-Sing; Povinelli, Louis A.; Conners, Timothy R.


    A relaxed isentropic compression supersonic inlet is a new concept that produces smaller cowl drag than a conventional inlet, but incurs lower total pressure recovery and increased flow distortion in the (radially) outer flowpath. A supersonic inlet comprising a bypass annulus to the relaxed isentropic compression inlet dumps out airflow of low quality through the bypass duct. A reliable computational fluid dynamics solution can provide considerable useful information to ascertain quantitatively relative merits of the concept, and further provide a basis for optimizing the design. For a fast and reliable performance evaluation of the inlet performance, an equivalent axisymmetric model whose area changes accounts for geometric and physical (blockage) effects resulting from the original complex three-dimensional configuration is proposed. In addition, full three-dimensional calculations are conducted for studying flow phenomena and verifying the validity of the equivalent model. The inlet-engine coupling is carried out by embedding numerical propulsion system simulation engine data into the flow solver for interactive boundary conditions at the engine fan face and exhaust plane. It was found that the blockage resulting from complex three-dimensional geometries in the bypass duct causes significant degradation of inlet performance by pushing the terminal normal shock upstream.

  18. Right ventricle contractility during early postoperative period after coronary artery bypass grafting with cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    А. Е. Баутин


    Full Text Available Emphasis in this research was placed on contractility of the right ventricle with regard to its relationship with systemic hemodynamics in patients undergoing coronary artery bypass grafting (CABG under cardiopulmonary bypass (CPB. The study included 25 patients (14 males, 11 females, mean age was 587 years admitted to ICU after CABG under CPB. All patients required inotropic therapy. The criterion for prescribing inotropic support in the postoperative period was a drop of the stroke volume index of the left ventricle below 35 ml/m 2 provided that the values of this indicator were normal before the perfusion period. Patients with previous pathology of the right ventricle or right coronary artery were excluded from the study. To evaluate the right ventricular function and systemic hemodynamics indicators, use was made of the PiCCO plus system and VoLEF addon device. It was found out that reduced contractility of the right ventricle may cause the reduction in stroke volume of the left ventricle with normal contractility. It was also observed that the increase of preload in patients with right ventricular ejection fraction less than 30% does not improve its function but leads to the increase of its end-diastolic volume. In 68% of cases, the need in inotropic agents in the early postoperative period after CABG was associated with the drop in right ventricle contractility, in 40% - with isolated right ven-tricular dysfunction. Patients with isolated reduction in right ventricle contractility required a longer period of inotropic support and ICU stay as compared with those with left ventricular failure.

  19. Cannabinoids mediate opposing effects on inflammation-induced intestinal permeability (United States)

    Alhamoruni, A; Wright, KL; Larvin, M; O'Sullivan, SE


    BACKGROUND AND PURPOSE Activation of cannabinoid receptors decreases emesis, inflammation, gastric acid secretion and intestinal motility. The ability to modulate intestinal permeability in inflammation may be important in therapy aimed at maintaining epithelial barrier integrity. The aim of the present study was to determine whether cannabinoids modulate the increased permeability associated with inflammation in vitro. EXPERIMENTAL APPROACH Confluent Caco-2 cell monolayers were treated for 24 h with IFNγ and TNFα (10 ng·mL−1). Monolayer permeability was measured using transepithelial electrical resistance and flux measurements. Cannabinoids were applied either apically or basolaterally after inflammation was established. Potential mechanisms of action were investigated using antagonists for CB1, CB2, TRPV1, PPARγ and PPARα. A role for the endocannabinoid system was established using inhibitors of the synthesis and degradation of endocannabinoids. KEY RESULTS Δ9-Tetrahydrocannabinol (THC) and cannabidiol accelerated the recovery from cytokine-induced increased permeability; an effect sensitive to CB1 receptor antagonism. Anandamide and 2-arachidonylglycerol further increased permeability in the presence of cytokines; this effect was also sensitive to CB1 antagonism. No role for the CB2 receptor was identified in these studies. Co-application of THC, cannabidiol or a CB1 antagonist with the cytokines ameliorated their effect on permeability. Inhibiting the breakdown of endocannabinoids worsened, whereas inhibiting the synthesis of endocannabinoids attenuated, the increased permeability associated with inflammation. CONCLUSIONS AND IMPLICATIONS These findings suggest that locally produced endocannabinoids, acting via CB1 receptors play a role in mediating changes in permeability with inflammation, and that phytocannabinoids have therapeutic potential for reversing the disordered intestinal permeability associated with inflammation. LINKED ARTICLES This

  20. Change in blood– brain barrier permeability during pediatric diabetic ketoacidosis treatment* (United States)

    Vavilala, Monica S.; Richards, Todd L.; Roberts, Joan S.; Chiu, Harvey; Pihoker, Catherine; Bradford, Heidi; Deeter, Kristina; Marro, Ken I.; Shaw, Dennis


    Objective Cerebral edema is a devastating complication of pediatric diabetic ketoacidosis. We aimed to examine blood– brain barrier permeability during treatment of diabetic ketoacidosis in children. Design Prospective observational study. Setting Seattle Children’s Hospital, Seattle, WA. Patients Children admitted with diabetic ketoacidosis (pH 300 mg/dL, and ketosis). Interventions None. Measurements and Main Results Subjects underwent two serial paired contrast-enhanced perfusion (gadolinium) and diffusion magnetic resonance imaging scans. Change in whole brain and regional blood– brain barrier permeability (permeability ratio*100 and % permeability ratio change) between illness and recovery were determined. Time 0 reflects start of insulin treatment. Thirteen children (median age 10.0 ± 1.1 yrs; seven female) with diabetic ketoacidosis were enrolled. Permeability ratio increased from time 1 (first magnetic resonance image after time 0) to time 2 (second magnetic resonance image after time 0) in the frontal cortex (ten of 13 subjects), occipital cortex (ten of 13 subjects), and basal ganglia (nine of 13). Whole brain permeability ratio increased from time 1 to time 2 (160%) and regional increase in permeability ratio was greatest in the frontal cortex (148%) compared with the occipital cortex (128%) and basal ganglia (112%). Conclusions Overall, whole brain and regional blood– brain barrier permeability increased in most subjects during diabetic ketoacidosis treatment. The frontal region had more blood– brain barrier permeability than other brain regions examined. PMID:19838141

  1. Ventilation during cardiopulmonary bypass did not attenuate inflammatory response or affect postoperative outcomes. (United States)

    Durukan, Ahmet Baris; Gurbuz, Hasan Alper; Salman, Nevriye; Unal, Ertekin Utku; Ucar, Halil Ibrahim; Yorgancioglu, C E M


    Cardiopulmonary bypass causes a series of inflammatory events that have adverse effects on the outcome. The release of cytokines, including interleukins, plays a key role in the pathophysiology of the process. Simultaneously, cessation of ventilation and pulmonary blood flow contribute to ischaemia-reperfusion injury in the lungs when reperfusion is maintained. Collapse of the lungs during cardiopulmonary bypass leads to postoperative atelectasis, which correlates with the amount of intrapulmonary shunt. Atelectasis also causes post-perfusion lung injury. In this study, we aimed to document the effects of continued low-frequency ventilation on the inflammatory response following cardiopulmonary bypass and on outcomes, particularly pulmonary function. Fifty-nine patients subjected to elective coronary bypass surgery were prospectively randomised to two groups, continuous ventilation (5 ml/kg tidal volume, 5/min frequency, zero end-expiratory pressure) and no ventilation, during cardiopulmonary bypass. Serum interleukins 6, 8 and 10 (as inflammatory markers), and serum lactate (as a marker for pulmonary injury) levels were studied, and alveolar- arterial oxygen gradient measurements were made after the induction of anaesthesia, and immediately, one and six hours after the discontinuation of cardiopulmonary bypass. There were 29 patients in the non-ventilated and 30 in the continuously ventilated groups. The pre-operative demographics and intra-operative characteristics of the patients were comparable. The serum levels of interleukin 6 (IL-6) increased with time, and levels were higher in the nonventilated group only immediately after discontinuation of cardiopulmonary bypass. IL-8 levels significantly increased only in the non-ventilated group, but the levels did not differ between the groups. Serum levels of IL-10 and lactate also increased with time, and levels of both were higher in the non-ventilated group only immediately after the discontinuation of

  2. Risk of stroke after coronary artery bypass grafting: effect of age and comorbidities

    DEFF Research Database (Denmark)

    Mérie, Charlotte; Køber, Lars; Olsen, Peter Skov


    The risk of stroke after coronary artery bypass grafting (CABG) is known to increase dramatically with age. During recent years, the age of patients operated on has increased and concomitant therapy has changed. Therefore, we have re-evaluated the risk of stroke after CABG.......The risk of stroke after coronary artery bypass grafting (CABG) is known to increase dramatically with age. During recent years, the age of patients operated on has increased and concomitant therapy has changed. Therefore, we have re-evaluated the risk of stroke after CABG....

  3. Effect of aggregate grain size distribution on properties of permeable ...

    African Journals Online (AJOL)

    ) ratio on the mechanical properties of permeable concrete is investigated. The aim of this study is to prepare permeable concrete mixture with optimum properties in terms of strength and permeability. For this purpose, five different permeable ...

  4. On the permeability of fractal tube bundles

    CERN Document Server

    Zinovik, I


    The permeability of a porous medium is strongly affected by its local geometry and connectivity, the size distribution of the solid inclusions and the pores available for flow. Since direct measurements of the permeability are time consuming and require experiments that are not always possible, the reliable theoretical assessment of the permeability based on the medium structural characteristics alone is of importance. When the porosity approaches unity, the permeability-porosity relationships represented by the Kozeny-Carman equations and Archie's law predict that permeability tends to infinity and thus they yield unrealistic results if specific area of the porous media does not tend to zero. The goal of this paper is an evaluation of the relationships between porosity and permeability for a set of fractal models with porosity approaching unity and a finite permeability. It is shown that the two-dimensional foams generated by finite iterations of the corresponding geometric fractals can be used to model poro...

  5. Cardiopulmonary bypass and edema: physiology and pathophysiology. (United States)

    Hirleman, E; Larson, D F


    Edema is a common morbidity following cardiopulmonary bypass (CPB) and can result in injury to many organs, including the heart, lungs, and brain. Generalized edema is also common and can lead to increased post-operative hospital stay and other morbidities. Pediatric patients are more susceptible to post-CPB edema and the consequences are more severe for this population. Hemodilution and systemic inflammatory responses are two suspected causes of CPB-related edema; however, the mechanisms involved are far from understood. Also, the common strategies to improve edema have not been completely successful and there is a need for new strategies at maintaining a fluid balance of patients as close to physiological as possible, especially for pediatric patients. An integrative approach to understanding edema is necessary as the forces involved in fluid homeostasis are dynamic and interdependent. Therefore, this review will focus on the physiology of fluid homeostasis and the pathologies of fluid shifts during CPB which lead to general edema as well as tissue-specific edema.

  6. Intestinal Permeability before and after Ibuprofen in Families of Children with Crohn’s Disease

    Directory of Open Access Journals (Sweden)

    Samuel A Zamora


    Full Text Available BACKGROUND: Members of a subset of first-degree relatives of adults with Crohn’s disease have been shown to have an increased baseline intestinal permeability and/or an exaggerated increase in intestinal permeability after the administration of acetylsalicylic acid.

  7. Endodontic sealers: Intratubular penetration and permeability to Enterococcus faecalis

    Directory of Open Access Journals (Sweden)

    Bortolini Maria Cecilia


    Full Text Available Aim : Evaluate in vitro the intratubular penetration and permeability of endodontic sealers in teeth contaminated with Enterococcus faecalis. Materials and Methods : Human canines were filled with AHPlus ® , Endo CPM-sealer ® or EndoRez ® sealers. To evaluate permeability, the coronary portion of each tooth was contaminated with E. faecalis, then the apical portion was immersed in brain heart infusion (BHI broth, and medium turbidity was observed for thirty days. Scanning electron microscope (SEM was used to evaluate the intratubular penetration of each sealer at the cervical, middle, and apical thirds of the tooth. Results : Only one tooth from the Endo CPM-sealer ® group presented broth contamination. EndoRez ® showed increased intratubular penetration compared to AHPlus ® and Endo CPM-sealer ® . Conclusions : Endo CPM-sealer ® showed greater permeability to E. faecalis and EndoRez ® showed increased intratubular penetration.

  8. Quantifying tidally driven benthic oxygen exchange across permeable sediments

    DEFF Research Database (Denmark)

    McGinnis, Daniel F.; Sommer, Stefan; Lorke, Andreas


    of permeable sediments and has been identified as increasingly at risk for developing hypoxia. Therefore, we investigate the benthic O-2 exchange across the permeable North Sea sediments using a combination of in situ microprofiles, a benthic chamber, and aquatic eddy correlation. Tidal bottom currents drive...... the variable sediment O-2 penetration depth (from approximate to 3 to 8 mm) and the concurrent turbulence-driven 25-fold variation in the benthic sediment O-2 uptake. The O-2 flux and variability were reproduced using a simple 1-D model linking the benthic turbulence to the sediment pore water exchange....... The high O-2 flux variability results from deeper sediment O-2 penetration depths and increased O-2 storage during high velocities, which is then utilized during low-flow periods. The study reveals that the benthic hydrodynamics, sediment permeability, and pore water redox oscillations are all intimately...

  9. Outcome after thrombolysis for occluded endoprosthesis, bypasses and native arteries in patients with lower limb ischemia. (United States)

    Kuoppala, Monica; Åkeson, Jonas; Acosta, Stefan


    To report contemporary outcomes, and evaluate differences after thrombolysis for occluded endoprosthesis, bypasses and native artery occlusion in patients with lower limb ischemia. Patients undergoing local intra-arterial thrombolysis for lower limb ischemia between 2001 and 2010 were identified in the prospective database for endovascular intervention, and analysis was performed retrospectively. There was an increase in thrombolysis for occluded endoprosthesis and a decrease in thrombolysis for occluded bypasses during the study period (p=0.001). The technical success rate for thrombolysis in occluded endoprosthesis, bypasses and native artery occlusion was 91%, 89% and 73%, respectively. The overall major amputation rate, mortality rate and amputation-free survival rate at 1 year was 19%, 14% and 73%, respectively, without differences between groups. The major amputation rate at long-term was highest, 45%, for patients with occluded synthetic bypass grafts. Female gender (HR 1.7; 95% CI 1.1-2.7), ischemic heart disease (HR 1.8; 95% CI 1.1-2.8), anemia at admission (HR 1.9; 95% CI 1.2-3.0), foot ulcer (HR 4.4; 95% CI 2.4-8.0), motor deficit at admission (HR 2.5; 95% CI 1.4-4.3), occluded synthetic bypass graft (HR 3.3; 95% CI 1.9-5.7) and failure of thrombolysis (HR 4.8; 95% CI 2.9-7.7) were independently associated with an increased long-term risk of major amputation. Thrombolysis for occluded endoprosthesis, bypasses and native artery occlusion was effective. Female gender, ischemic heart disease, anemia, foot ulcer, motor deficit, occluded synthetic bypass graft and failure of thrombolysis were independently associated with an increased risk of major amputation. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Bypass of an anesthesiologist-directed preoperative evaluation clinic results in greater first-case tardiness and turnover times. (United States)

    Epstein, Richard H; Dexter, Franklin; Schwenk, Eric S; Witkowski, Thomas A


    We evaluated 4 hypotheses related to bypass of an anesthesiologist-directed preoperative evaluation clinics (APEC): 1) first-case tardiness and turnover times increased; 2) turnover times increased more than first-case tardiness; and higher American Society of Anesthesiologists Physical Status (ASA PS) resulted in both an ordered increase among ASA PS and within ASA PS in 3) first-case tardiness; and 4) turnover times. Retrospective observational study using electronic health records. One large, teaching hospital. An average of 14,310 patients per year undergoing elective surgery in the hospital's main opera rating rooms who were not inpatients preoperatively between 2006 and 2016. None. Average increases in first-case tardiness and turnover times between patients seen or not seen preoperatively in the APEC. APEC bypass increased first-case tardiness 2.58 min per case (CI 1.55-3.61; PAPEC, the increase in total minutes OR- 1 workday- 1 for turnover times would have been larger than the increase in first-case tardiness (difference=5.71, CI 3.17-4.72; PAPEC bypass for both first-case tardiness and turnover times with increasing ASA PS (PAPEC bypass. All 4 hypotheses were accepted. Overall and with control for ASA PS, APEC bypass increases first-case tardiness and turnover times. A strategy of selective bypass of ASA PS 1-2 patients would not be effective economically because of substantial delays from ASA PS 2 patients. Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Permeability reduction by asphaltenes and resins deposition in porous media

    Energy Technology Data Exchange (ETDEWEB)

    R. Hamadou; M. Khodja; M. Kartout; A. Jada [Sonatrach/Division Centre de Recherche et Developpement, Boumerdes (Algeria)


    The deposition of crude oil polar fractions such as asphaltenes and resins in oil reservoir rocks reduce considerably the rock permeability and the oil production. In the present work, a crude oil and various core samples were extracted from Rhourd-Nouss (RN) reservoir rock. Afterwards, core flow experiments were carried out in the laboratory to investigate permeability reduction that causes formation damage. The core permeability damage was evaluated by flooding Soltrol, through the sample and measuring the solvent permeabilities, K{sub I} and K{sub f}, respectively, before and after injection of a given pore volume number of the crude oil. The data indicate that upon flooding the crude oil through the porous medium, considerable permeability reduction, expressed as the ratio (K{sub I} - K{sub f})/K{sub I}, and ranging from 72.4% to 98.3% were observed. The permeability reduction is found to result from irreversible retention of asphaltenes and resins in the porous core sample. However, no correlations could be established between the depth of the well, the core porosity, the core mineral compositions determined by X-ray analysis, and the permeability damage factors. In addition, effluents flowing away from RN wells were collected and analysed at various periods, after carrying out aromatic solvents squeezes. The amount of saturates, aromatics, resins, and asphaltenes (SARA analysis), of the crude oil, the deposited crude oil fraction, and the effluent's residues were measured and compared. The asphaltenes weight percent was found to increase from 1.56% for the crude oil to 11.42% for the deposited oil fraction, and was in the range 1.37-2.36% for the effluent's residues. Such results indicate that the deposited oil fraction and the effluent's residues consist mainly of asphaltenes and resins. 26 refs., 1 fig., 11 tabs.

  12. The effect of permeability on the flow past permeable disks at low Reynolds numbers (United States)

    Cummins, Cathal; Viola, Ignazio Maria; Mastropaolo, Enrico; Nakayama, Naomi


    The viscous flow over a thick permeable circular disk in the Reynolds number (Re) range of 10 to 130 and in the Darcy number (Da) range of 10-9 to 1 is examined. Direct numerical simulations are performed on a 2D grid with axisymmetric boundary conditions. Three flow regimes are observed: I, II, and III. In regime I (effectively impervious; D a 1 0-3) is the highly permeable regime, in which there is no recirculation. In I, good agreement with existing experimental data for impervious disks is found. In III, an analytical expression for the drag force on the disk is derived, showing good agreement with the numerical results. A global upper limit of D ac=D amax above which the disk is unable to maintain a recirculating wake for any Re is identified. Finally, in regime II, it is demonstrated that increasing the permeability can lead to large variations in the length of the recirculating wake but with minimal effect on the drag coefficient even when D a >D amax. This has important implications in our understanding of the locomotive strategies adopted by organisms that use porous bodies for movement.

  13. Internal Maxillary Bypass for Complex Pediatric Aneurysms. (United States)

    Wang, Long; Lu, Shuaibin; Qian, Hai; Shi, Xiang'en


    Complex pediatric aneurysms (PAs) are an unusual clinicopathologic entity. Data regarding the use of a bypass procedure to treat complex PAs are limited. Internal maxillary artery-to-middle cerebral artery bypass with radial artery graft was used to isolate PAs. Bypass patency and aneurysm stability were evaluated using intraoperative Doppler ultrasound, indocyanine green videoangiography, and postoperative angiography. Modified Rankin Scale was used to assess neurologic function. Over a 5-year period, 7 pediatric patients (≤18 years old) were included in our analysis. Mean age of patients was 14.4 years (range, 12-18 years), and mean size of PAs was 23.6 mm (range, 9-37 mm). All cases manifested with complex characteristics. Proximal artery occlusion was performed in 3 cases, complete excision following aneurysmal distal internal maxillary artery bypass was performed in 2 cases, and combined proximal artery occlusion and aneurysm excision was performed in the 2 remaining cases. Mean intraoperative blood flow was 61.6 mL/minute (range, 40.0-90.8 mL/minute). Graft patency rate was 100% during postoperative recovery and at the last follow-up examination (mean, 20 months; range, 7-45 months). All patients had excellent outcomes except for 1 patient who died of multiple-organ failure. Internal maxillary artery bypass is an essential technique for treatment of selected cases of complex PAs. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. Hepatic Injury in Nonalcoholic Steatohepatitis Contributes to Altered Intestinal PermeabilitySummary

    Directory of Open Access Journals (Sweden)

    Jay Luther


    Full Text Available Background & Aims: Emerging data suggest that changes in intestinal permeability and increased gut microbial translocation contribute to the inflammatory pathway involved in nonalcoholic steatohepatitis (NASH development. Numerous studies have investigated the association between increased intestinal permeability and NASH. Our meta-analysis of this association investigates the underlying mechanism. Methods: A meta-analysis was performed to compare the rates of increased intestinal permeability in patients with NASH and healthy controls. To further address the underlying mechanism of action, we studied changes in intestinal permeability in a diet-induced (methionine-and-choline-deficient; MCD murine model of NASH. In vitro studies were also performed to investigate the effect of MCD culture medium at the cellular level on hepatocytes, Kupffer cells, and intestinal epithelial cells. Results: Nonalcoholic fatty liver disease (NAFLD patients, and in particular those with NASH, are more likely to have increased intestinal permeability compared with healthy controls. We correlate this clinical observation with in vivo data showing mice fed an MCD diet develop intestinal permeability changes after an initial phase of liver injury and tumor necrosis factor-α (TNFα induction. In vitro studies reveal that MCD medium induces hepatic injury and TNFα production yet has no direct effect on intestinal epithelial cells. Although these data suggest a role for hepatic TNFα in altering intestinal permeability, we found that mice genetically resistant to TNFα-myosin light chain kinase (MLCK–induced intestinal permeability changes fed an MCD diet still develop increased permeability and liver injury. Conclusions: Our clinical and experimental results strengthen the association between intestinal permeability increases and NASH and also suggest that an early phase of hepatic injury and inflammation contributes to altered intestinal

  15. Permeability Modification Using a Reactive Alkaline-Soluble Biopolymer

    Energy Technology Data Exchange (ETDEWEB)

    Snadra L. Fox; X. Xie; K. D. Schaller; E. P. Robertson; G. A. Bala


    Polymer injection has been used in reservoirs to alleviate contrasting permeability zones. Current technology relies on the use of cross-linking agents to initiate gelation. The use of biological polymers are advantageous in that they can block high permeability areas, are environmentally friendly, and have potential to form reversible gels without the use of hazardous cross-linkers. Recent efforts at the Idaho National Engineering and Environmental Laboratory (INEEL) have produced a reactive alkaline-soluble biopolymer from Agrobacterium sp. ATCC no. 31749 that gels upon decreasing the pH of the polymeric solution. The focus of this study was to determine the impact an alkaline-soluble biopolymer can have on sandstone permeability. Permeability modification was investigated by injecting solubilized biopolymer into Berea sandstone cores and defining the contribution of pH, salt, temperature, and Schuricht crude oil on biopolymer gelation. The biopolymer was soluble in KOH at a pH greater than 11.4 and gelled when the pH dropped below 10.8. The Berea sandstone core buffered the biopolymer solution, decreasing the pH sufficiently to form a gel, which subsequently decreased the permeability. The effluent pH of the control cores injected with 0.01 {und M} KOH (pH 12.0) and 0.10{und M} KOH (pH 13.0) decreased to 10.6 and 12.7, respectively. The permeability of the sandstone core injected with biopolymer was decreased to greater than 95% of the original permeability at 25 C in the presence of 2% NaCl, and Schuricht crude oil; however, the permeability increased when the temperature of the core was increased to 60 C. Residual resistance factors as high as 792 were seen in Berea cores treated with biopolymer. The buffering capacity of sandstone has been demonstrated to reduce the pH of a biopolymer solution sufficiently to cause the polymer to form a stable in-situ gel. This finding could potentially lead to alternate technology for permeability modification, thus

  16. Use and Outcomes of Laparoscopic Sleeve Gastrectomy vs Laparoscopic Gastric Bypass: Analysis of the American College of Surgeons NSQIP. (United States)

    Young, Monica T; Gebhart, Alana; Phelan, Michael J; Nguyen, Ninh T


    Laparoscopic sleeve gastrectomy is gaining popularity in the United States. However, few studies have examined outcomes of sleeve gastrectomy compared with those of the "gold standard" bariatric operation: Roux-en-Y gastric bypass. Using the American College of Surgeons National Surgical Quality Improvement Program database, clinical data were obtained for all patients who underwent laparoscopic sleeve gastrectomy or laparoscopic gastric bypass between 2010 and 2011. Main outcomes measures were risk-adjusted 30-day serious morbidity and mortality. We analyzed 24,117 patients who underwent laparoscopic sleeve gastrectomy or laparoscopic gastric bypass for the treatment of morbid obesity. Gastric bypass comprised 79.5% of cases and sleeve gastrectomy comprised 20.5%; the proportion of sleeve gastrectomy cases increased from 14.6% in 2010 to 25.8% in 2011. On univariate analysis, sleeve gastrectomy had a shorter mean operative time (101 vs 133 minutes, p sleeve gastrectomy, gastric bypass patients had higher risk-adjusted 30-day serious morbidity (odds ratio [OR] 1.32; 95% CI1.11 to 1.56, p sleeve vs 0.15% for bypass). Use of laparoscopic sleeve gastrectomy is increasing on a national level. Compared with laparoscopic gastric bypass, laparoscopic sleeve gastrectomy is associated with lower 30-day risk-adjusted serious morbidity and equivalent 30-day mortality. Copyright © 2015 American College of Surgeons. Published by Elsevier Inc. All rights reserved.

  17. Haemophilia, AIDS and lung epithelial permeability

    Energy Technology Data Exchange (ETDEWEB)

    O' Doherty, M.J.; Page, C.J.; Harrington, C.; Nunan, T.; Savidge, G. (Haemophilia Centre and Coagulation Research Unit, Department of Nuclear Medicine, Rayne Institute, St. Thomas' Hospital, London (United Kingdom))


    Lung {sup 99m}Tc DTPA transfer was measured in HIV antibodypositive haemophiliacs (11 smokers, 26 nonsmokers, 5 patients with Pneumocystis carinii pneumonia (PCP)). Lung {sup 99m}Tc DTPA transfer as a marker of lung epithelial permeability was measured as the half time of transfer (from airspace into blood). This half time was faster in smokers compred to nonsmokers and the transfer curve was monoexponential. In nonsmokers no difference was observed between asymptomatic HIV-positive haemophiliacs and normal subjects, with the exception of the lung bases. At the lung basis in HIV-positive haemophiliac nonsmokers the transfer was faster than in normal individuals, implying increased alveolar permeability. Pneumocystis carinii pneumonia resulted in a rapid transfer of {sup 99m}Tc DTPA (mean T50 of 2 minutes) and the transfer curve was biphasic, confirming previous observations in homosexual HIV antibody-positive patients with PCP. These changes returned to a monoexponential profile by 6 weeks following successful treatment. The DTPA lung transfer study may enable clinicians to instigate therapy for PCP without the need for initial bronchoscopy and provide a noninvasive method for the reassessment of patients should further respiratory signs or symptoms develop. This method is considered to be highly cost-effective in that it obviates the use of factor VIII concentrates required to cover bronchoscopic procedures and, with its early application and ease of use as a follow-up investigation, permits the evaluation of patients on an outpatient basis, thus reducing hospital costs. (au).

  18. Are patients bypassing paediatric cardiology outreach clinics? (United States)

    Fletcher, Alexander; Samson, Ray; McLeod, Karen


    Previous studies have identified that receiving specialist care close to home can positively influence patients' experience. Despite this, a review of cardiology outpatient appointments at the Royal Hospital for Children in Glasgow demonstrated that a large number of families are bypassing their local children's cardiology centre to attend cardiac clinics at the specialist children's surgical centre. We used patient questionnaire, audit of local facilities, and examined the relationship between diagnosis and bypass numbers to better understand factors influencing this trend. Our results suggest that patient preference, short travelling distance to specialist children's cardiac centre, a more severe cardiac diagnosis, and inconsistent local facilities, expertise, and support are likely to influence a family's decision to bypass their local children's cardiology centre.

  19. Doppler spectral characteristics of infrainguinal vein bypasses

    DEFF Research Database (Denmark)

    Nielsen, Tina G; von Jessen, F; Sillesen, H


    of arteriovenous fistulas the initially antegrade diastolic velocity was replaced by a retrograde flow within 3 months, whereas a forward flow in diastole was sustained in grafts with patent fistulas. Abnormal Duplex findings in 31 patients led to angiography and revision in 13 cases. Four revised grafts failed......, while nine remained patent at follow-up 1-12 months later. Ten (56%) of 18 non-revised bypasses with abnormal Duplex findings failed within 9 months compared to 1 (1%) of 76 bypasses with a normal velocity profile (p ... valuable information concerning haemodynamics of infrainguinal vein bypasses and identifies grafts at risk of thrombosis. Inclusion of low resistance index (detection of stenoses appears to improve the sensitivity of Duplex scanning....

  20. Hydrodynamic Forcing Mobilizes Cu in Low-Permeability Estuarine Sediments. (United States)

    Xie, Minwei; Wang, Ning; Gaillard, Jean-François; Packman, Aaron I


    Overlying hydrodynamics play critical roles in controlling surface-porewater exchanges in permeable sediments, but these effects have rarely been characterized in low-permeability sediments. We conducted a series of laboratory experiments to evaluate the effects of varied hydrodynamic conditions on the efflux of metals from low-permeability estuarine sediments. Two Cu-contaminated sediments obtained from the Piscataqua River were subject to controlled levels of hydrodynamic shear in Gust mesocosms, including episodic sediment resuspension. Overlying water and porewater samples were collected over the course of experiments and analyzed for metal concentrations. The two sediments had similar permeability (∼10(-15) m(2)), but different particle size distributions. Hydrodynamic forcing enhanced the mobilization and efflux of Cu from the coarser-grained sediments, but not the finer-grained sediments. Sediment resuspension caused additional transitory perturbations in Cu concentrations in the water column. Particulate metal concentrations increased significantly during resuspension, but then rapidly decreased to preresuspension levels following cessation of sediment transport. Overall, these results show that the mobility and efflux of metals are likely to be influenced by overlying hydrodynamics even in low-permeability sediments, and these effects are mediated by sediment heterogeneity and resuspension.

  1. Bypassing health facilities for childbirth: a multilevel study in three districts of Gujarat, India. (United States)

    Salazar, Mariano; Vora, Kranti; Costa, Ayesha De


    Bypassing available facilities for childbirth has important implications for maternal health service delivery and human resources within a health system. The results are the additional expenses imposed on the woman and her family, as well as the inefficient use of health system resources. Bypassing often indicates a lack of confidence in the care provided by the facility nearest to the mother, which implies a level of dysfunctionality that the health system needs to address. Over the past decade, India has experienced a steep rise in the proportion of facility births. The initiation of programs promoting facility births resulted in a rise from 39% in 2005 to 85% in 2014. There have been no reports on bypassing facilities for childbirth from India. In the context of steeply rising facility births, it is important to quantify the occurrence of and study the relative contributions of maternal characteristics and facility functionality to bypassing. 1) To determine the extent of bypassing health facilities for childbirth among rural mothers in three districts of Gujarat, India, 2) to identify associations between the functionality of an obstetric care (OC) facility and it being bypassed, and 3) to assess the relative contribution of maternal and facility characteristics to bypassing. A cross-sectional survey of 166 public and private OC facilities reporting ≥30 births in the 3 months before the survey was conducted in three purposively selected districts (Dahod, Sabarkantha, and Surendranagar) in the state of Gujarat, India. Besides information on each facility, data from 946 women giving birth at these facilities were also gathered. Data were analyzed using a multilevel mixed-effects logistic regression model. Off all mothers, 37.7% bypassed their nearest facility for childbirth. After adjusting for maternal characteristics, for every one-unit increase in the facility's emergency obstetric care (EmOC) signal functions, the odds of bypassing a facility for childbirth

  2. Endothelin and vasopressin influence splanchnic blood flow distribution during and after cardiopulmonary bypass. (United States)

    Bomberg, Hagen; Bierbach, Benjamin; Flache, Stephan; Wagner, Isabell; Gläser, Lena; Groesdonk, Heinrich V; Menger, Michael D; Schäfers, Hans-Joachim


    Gastrointestinal blood flow can be compromised during and after cardiopulmonary bypass. Endothelin has been shown to be involved in the intestinal microcirculatory disturbance of sepsis. The aim of the present study was to analyze the involvement of the endothelin system on intestinal blood flow regulation during cardiopulmonary bypass and the effect of vasopressin given during cardiopulmonary bypass. A total of 24 pigs were studied in 4 groups (n = 6): group I, sham; group II, ischemia/reperfusion with 1 hour of superior mesenteric artery occlusion; group III, cardiopulmonary bypass for 1 hour; and group IV, 1 hour of cardiopulmonary bypass plus vasopressin administration, maintaining the baseline arterial pressure. All the pigs were reperfused for 90 minutes. During the experiment, the hemodynamics and jejunal microcirculation were measured continuously. The jejunal mucosal expression of endothelin-1 and its receptor subtypes A and B were determined using polymerase chain reaction. During cardiopulmonary bypass, superior mesenteric artery flow was preserved but marked jejunal microvascular impairment occurred compared with baseline (mucosal capillary density, 192.2 ± 5.4 vs 150.8 ± 5.1 cm/cm(2); P = .005; tissue blood flow, 501.7 ± 39.3 vs 332.3 ± 27.9 AU; P = .025). The expression of endothelin-1 after cardiopulmonary bypass (3.2 ± 0.4 vs 12.2 ± 0.8 RQ, P = .006) and endothelin subtype A (0.7 ± 0.2 vs 2.4 ± 0.6 RQ; P = .01) was significantly increased compared to the sham group. Vasopressin administration during cardiopulmonary bypass led to normal capillary density (189.9 ± 3.9 vs 178.0 ± 6.3; P = .1) and tissue blood flow (501.7 ± 39.3 vs 494.7 ± 44.4 AU; P = .4) compared with baseline. The expression of endothelin-1 (3.2 ± 0.4 vs 1.8 ± 0.3 RQ; P = .3) and endothelin subtype A (0.7 ± 0.2 vs 0.9 ± 0.2 RQ; P = .5) was not different from the sham group. Cardiopulmonary bypass leads to microvascular impairment of jejunal microcirculation, which is

  3. Gap junction protein connexin43 exacerbates lung vascular permeability.

    Directory of Open Access Journals (Sweden)

    James J O'Donnell

    Full Text Available Increased vascular permeability causes pulmonary edema that impairs arterial oxygenation and thus contributes to morbidity and mortality associated with Acute Respiratory Distress Syndrome and sepsis. Although components of intercellular adhesive and tight junctions are critical for maintaining the endothelial barrier, there has been limited study of the roles of gap junctions and their component proteins (connexins. Since connexins can modulate inflammatory signaling in other systems, we hypothesized that connexins may also regulate pulmonary endothelial permeability. The relationships between connexins and the permeability response to inflammatory stimuli were studied in cultured human pulmonary endothelial cells. Prolonged treatment with thrombin, lipopolysaccharide, or pathological cyclic stretch increased levels of mRNA and protein for the major connexin, connexin43 (Cx43. Thrombin and lipopolysaccharide both increased intercellular communication assayed by transfer of microinjected Lucifer yellow. Although thrombin decreased transendothelial resistance in these cells, the response was attenuated by pretreatment with the connexin inhibitor carbenoxolone. Additionally, the decreases of transendothelial resistance produced by either thrombin or lipopolysaccharide were attenuated by reducing Cx43 expression by siRNA knockdown. Both carbenoxolone and Cx43 knockdown also abrogated thrombin-induced phosphorylation of myosin light chain. Taken together, these data suggest that increased lung vascular permeability induced by inflammatory conditions may be amplified via increased expression of Cx43 and intercellular communication among pulmonary endothelial cells.

  4. Pulmonary epithelial permeability in rats with bleomycin-induced pneumonitis

    Energy Technology Data Exchange (ETDEWEB)

    Anazawa, Yoshiki; Isawa, Toyoharu; Teshima, Takeo; Miki, Makoto; Motomiya, Masakichi (Tohoku Univ., Sendai (Japan). Research Inst. for Tuberculosis and Cancer)


    This study was performed to investigate the mechanism by which [sup 99m]Tc-DTPA molecules pass through the pulmonary epithelium following inhalation of [sup 99m]Tc-DTPA aerosol. Interstitial pneumonitis was induced in 6-week-old male rats by instilling 1 mg/kg of bleomycin into the trachea. Disappearance of radioactivity from the lungs was measured with a gamma camera every 2 weeks to estimate pulmonary epithelial permeability, and light- and electron-microscopic histopathologic examinations were performed at the same intervals. There was a statistically significant increase in the pulmonary epithelial permeability at 2 weeks after the instillation of bleomycin. However, subsecquent changes in pulmonary epithelial permeability were not uniform; some animals showed recovery and some showed further increase and/or partial recovery. Microscopically, increase in the capillary bed, round cell infiltration, and widening of the interstitial space were observed in addition to the presence of macrophages in the alveolar spaces at 2 weeks. Electron microscopic examination revealed vacuolization, thinning and detachment of the alveolar epithelium, and denudation of the basement membrane. Prominent fibrosis, honeycombing, thinning of the pulmonary epithelium, and increase in collagen fibers were observed after 18 weeks. We consider that vacuolization, thinning, and detachment of the pulmonary epithelium and denudation of the basement membrane are related to the increase in pulmonary epithelial permeability in bleomycin-induced interstitial pneumonitis. (author).

  5. Increased morbidity in patients undergoing abdominoplasty after laparoscopic gastric bypass

    DEFF Research Database (Denmark)

    Breiting, Line Bro; Lock-Andersen, Jørgen; Matzen, Steen Henrik


    INTRODUCTION: 30-40% of the adult population in Denmark are overweight and 10-13% are obese. The number of bariatric operations reached 3,000 in 2009, and it is expected that a third or more of the patients need corrective plastic surgery. MATERIAL AND METHODS: Medical charts of all patients who...... had abdominoplasty performed during a 2.5-year period. We included 72 patients of whom 21 had lost weight after bariatric surgery and 51 patients had lost weight through diet and exercise or had not been overweight. RESULTS: The overall complication rate was 21% (43% of the post-bariatric patients...... a significantly higher maximum weight, weight at the time of abdominoplasty and had lost more BMI units. CONCLUSION: Our data show that post-bariatric patients who have an abdominoplasty performed suffer a high complication rate which appears to be higher than that of patients who do not have bariatric surgery...

  6. Increased morbidity in patients undergoing abdominoplasty after laparoscopic gastric bypass

    DEFF Research Database (Denmark)

    Breiting, Line Bro; Lock-Andersen, Jørgen; Matzen, Steen Henrik


    INTRODUCTION: 30-40% of the adult population in Denmark are overweight and 10-13% are obese. The number of bariatric operations reached 3,000 in 2009, and it is expected that a third or more of the patients need corrective plastic surgery. MATERIAL AND METHODS: Medical charts of all patients who ...

  7. Minimally invasive coronary artery bypass grafting: a systematic review. (United States)

    Kikuchi, Keita; Mori, Makoto


    To minimize surgical morbidity in coronary artery bypass grafting, minimally invasive cardiac surgery has gained popularity. Minimally invasive coronary artery bypass grafting offers unique advantages compared to conventional off-pump coronary artery bypass or minimally invasive direct coronary artery bypass in that it enables the surgeon to harvest and graft bilateral internal thoracic arteries via a small thoracotomy while being conducted completely off-pump. This review focuses on current evidence behind off-pump coronary artery bypass, multi-arterial revascularization, patient populations that would most benefit from bilateral internal thoracic artery minimally invasive coronary artery bypass grafting, the surgical technique, and early outcomes. By overcoming the perceived inability to utilize bilateral internal thoracic arteries in minimally invasive coronary artery bypass grafting, the new technique further expands the armamentarium of surgeons and cardiologists. Hybrid coronary revascularization with bilateral internal thoracic artery minimally invasive coronary artery bypass grafting further augments the appeal of the next generation of minimally invasive cardiac surgery.

  8. Gastric Bypass Surgery: What Happens If I Regain the Weight? (United States)

    ... happens if you gain back weight after gastric bypass surgery? Answers from Katherine Zeratsky, R.D., L. ... If you begin to regain weight after gastric bypass surgery, talk to your doctor. You may have ...

  9. Steam-water relative permeability

    Energy Technology Data Exchange (ETDEWEB)

    Ambusso, W.; Satik, C.; Home, R.N. [Stanford Univ., CA (United States)


    A set of relative permeability relations for simultaneous flow of steam and water in porous media have been measured in steady state experiments conducted under the conditions that eliminate most errors associated with saturation and pressure measurements. These relations show that the relative permeabilities for steam-water flow in porous media vary approximately linearly with saturation. This departure from the nitrogen/water behavior indicates that there are fundamental differences between steam/water and nitrogen/water flows. The saturations in these experiments were measured by using a high resolution X-ray computer tomography (CT) scanner. In addition the pressure gradients were obtained from the measurements of liquid phase pressure over the portions with flat saturation profiles. These two aspects constitute a major improvement in the experimental method compared to those used in the past. Comparison of the saturation profiles measured by the X-ray CT scanner during the experiments shows a good agreement with those predicted by numerical simulations. To obtain results that are applicable to general flow of steam and water in porous media similar experiments will be conducted at higher temperature and with porous rocks of different wetting characteristics and porosity distribution.

  10. Analgesic Treatment in Laparoscopic Gastric Bypass Surgery

    DEFF Research Database (Denmark)

    Andersen, Lars P H; Werner, Mads U; Rosenberg, Jacob


    This review aimed to present an overview of the randomized controlled trials investigating analgesic regimens used in laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery. Literature search was performed in PubMed and EMBASE databases in August 2013 in accordance to PRISMA guidelines. The litera......This review aimed to present an overview of the randomized controlled trials investigating analgesic regimens used in laparoscopic Roux-en-Y gastric bypass (LRYGB) surgery. Literature search was performed in PubMed and EMBASE databases in August 2013 in accordance to PRISMA guidelines...

  11. Experimental Study on Permeability of Concrete (United States)

    Yang, Honglu; Liu, Rentai; Zheng, Zhuo; Liu, Haojie; Gao, Yan; Liu, Yankai


    To study the influencing factors on permeability of pervious concrete, by adding inorganic organic composite materials obtained experimental results show that different aggregate size, aggregate cement ratio of different, different water cement ratio on the permeability performance. The permeability of the concrete was tested by using the self - made permeable device. The experimental results showed that the permeation coefficient of the experiment was obtained and the factors influencing the permeability of the concrete were compared and analyzed. At the same time, the porosity of pervious concrete was measured, the influence of various variables on porosity was studied, and the influence of various factors on the permeability of voids was found. Finally, through comprehensive analysis of a variety of factors, the optimal water cement ratio is 0.28. At this time, the pervious performance of concrete is optimal.

  12. Permeability Evolution of Propped Artificial Fractures in Green River Shale (United States)

    Li, Xiang; Feng, Zijun; Han, Gang; Elsworth, Derek; Marone, Chris; Saffer, Demian; Cheon, Dae-Sung


    This paper compares the evolution of permeability with effective stress in propped fractures in shale for native CH4 compared with that for sorbing CO2, slightly sorbing N2 and non-sorbing He. We examine the response for laboratory experiments on artificial propped fractures in Green River Shale to explore mechanisms of proppant embedment and fracture diagenesis. Split cylindrical specimens sandwich a proppant bead-pack at a constant confining stress of 20 MPa and with varied pore pressure. Permeability and sorption characteristics are measured with the pulse transient method. To explore the effect of swelling and embedment on fracture surface geometry, we measure the evolution of conductivity characteristics for different proppant geometries (single layer vs. multilayer), gas saturation and specimen variation in order to simulate both production and enhanced gas recovery. The resulting morphology of embedment is measured by white light interferometry and characterized via surface roughness parameter of mean, maximum and root-mean-square amplitudes. For both strongly (CO2, CH4) and slightly adsorptive gases (N2), the permeability first decreases with an increase in gas pressure due to swelling before effective stress effects dominate above the Langmuir pressure threshold. CO2 with its highest adsorption affinity produces the lowest permeability among these three gas permeants. Monolayer propped specimens show maximum swelling and lowered k/k 0 ratio and increased embedment recorded in the surface roughness relative to the multilayered specimens. Permeabilities measured for both injection and depletion cycles generally overlap and are repeatable with little hysteresis. This suggests the dominant role of reversible swelling over irreversible embedment. Gas permeant composition and related swelling have an important effect on the permeability evolution of shales.

  13. Does Off-Pump Coronary Artery Bypass Grafting Negatively Impact Long-Term Survival and Freedom from Reintervention?

    Directory of Open Access Journals (Sweden)

    Shahzad G. Raja


    Full Text Available Recently published evidence has raised concerns about worse late mortality and increasing need for reintervention after off-pump coronary artery bypass grafting. We undertook this study to assess the impact of off-pump coronary artery bypass grafting on survival and freedom from reintervention at 10 years. From January 2002 to December 2002, 307 consecutive patients who had isolated multivessel off-pump coronary artery bypass grafting at our institution were compared to a control group of 397 patients that underwent multivessel on-pump coronary artery bypass grafting during the same period. In addition, univariate and risk-adjusted comparisons between the two groups were performed at 10 years. Kaplan-Meier survival was similar for the two cohorts. After adjusting for clinical covariates, off-pump coronary artery bypass grafting did not emerge as a significant independent predictor of long-term mortality (Hazard Ratio 0.91; 95% Confidence Interval 0.70–1.12, readmission to hospital for cardiac cause (Hazard Ratio 0.96; 95% Confidence Interval 0.78–1.10, or the need for reintervention (Hazard Ratio 0.93; 95% Confidence Interval 0.87–1.05. Off-pump coronary artery bypass grafting compared with on-pump coronary artery bypass grafting does not adversely impact survival or freedom from reintervention at a 10-year follow-up.

  14. Nutrient Infiltrate Concentrations from Three Permeable Pavement Types (United States)

    While permeable pavement is increasingly being used to control stormwater runoff, field-based, side-by-side investigations on the effects different pavement types have on nutrient concentrations present in stormwater runoff are limited. In 2009, the U.S. EPA constructed a 0.4-ha...

  15. Permeability and compressibility of CNT/CNF grafted reinforcements

    NARCIS (Netherlands)

    Lomov, Stepan V.; Beyers, Lesley; Gorbatikh, Larissa; Verpoest, Ignaas; Koysin, V.; Kotanjac, Zeljko; Karahan, Mehmet


    The paper studies compressibility and permeability of a CNT/CNF-grafted woven carbon reinforcement. It is shown that the pressure needed to achieve the target fibre volume fraction of the perform increases drastically when CNT/CNF are present in the preform. This can lower the achievable fibre

  16. Lung management during cardiopulmonary bypass: influence on extravascular lung water. (United States)

    Boldt, J; King, D; Scheld, H H; Hempelmann, G


    Progressive respiratory insufficiency secondary to cardiopulmonary bypass (CPB) is still a hazard after cardiac surgery. Pathophysiologically, impaired capillary endothelial integrity seems to be the fundamental lesion, followed by increased interstitial fluid accumulation. The reasons for this pulmonary damage are controversial; however, management of the nonperfused lungs during CPB has been widely neglected and may be partly responsible. In this study, 90 patients undergoing coronary artery bypass grafting were randomly divided into six groups (15 patients each) with different management of the lungs during CPB: group 1, lungs collapsed (0/0); group 2, static inflation with +5 cm H2O and F1O2 1.0 (+5/1.0); group 3, static inflation with +5 cm H2O and F1O2 0.21 (+5/0.21); group 4, static inflation with +15 cm H2O and F1O2 1.0 (+15/1.0); group 5, static inflation with +15 cm H2O and F1O2 0.21 (+15/0.21); and group 6, controlled mechanical ventilation as before start of CPB (positive end-expiratory pressure [PEEP] +5 cm H2O; F1O2 1.0) (ventilation). In addition to hemodynamic monitoring, extravascular lung water (EVLW) was measured by means of a double-indicator dilution technique with heat and indocyanine green. Measurements were performed after induction of anesthesia, before onset of CPB, and immediately after weaning from bypass, as well as 60 minutes and 5 hours after termination of CPB. Pulmonary gas exchange (PaO2) and intrapulmonary shunting (Qs/Qt) were also measured. Starting from comparable, normal baseline values, EVLW was increased in all groups after weaning from CPB, with the most pronounced increase in group 4 (maximum, +35%) and group 5 (+40%).(ABSTRACT TRUNCATED AT 250 WORDS)

  17. 21 CFR 870.4240 - Cardiopulmonary bypass heat exchanger. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass heat exchanger. 870.4240... bypass heat exchanger. (a) Identification. A cardiopulmonary bypass heat exchanger is a device, consisting of a heat exchange system used in extracorporeal circulation to warm or cool the blood or...

  18. 21 CFR 870.4230 - Cardiopulmonary bypass defoamer. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass defoamer. 870.4230 Section... bypass defoamer. (a) Identification. A cardiopulmonary bypass defoamer is a device used in conjunction... entitled “Guidance for Extracorporeal Blood Circuit Defoamer 510(k) Submissions.” [45 FR 7907-7971, Feb. 5...

  19. 21 CFR 870.4250 - Cardiopulmonary bypass temperature controller. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass temperature controller. 870... Cardiopulmonary bypass temperature controller. (a) Identification. A cardiopulmonary bypass temperature controller is a device used to control the temperature of the fluid entering and leaving a heat exchanger. (b...

  20. 21 CFR 870.4400 - Cardiopulmonary bypass blood reservoir. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass blood reservoir. 870.4400... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Surgical Devices § 870.4400 Cardiopulmonary bypass blood reservoir. (a) Identification. A cardiopulmonary bypass blood reservoir is a device used in...

  1. 21 CFR 870.4300 - Cardiopulmonary bypass gas control unit. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass gas control unit. 870.4300... (CONTINUED) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Surgical Devices § 870.4300 Cardiopulmonary bypass gas control unit. (a) Identification. A cardiopulmonary bypass gas control unit is a device used...

  2. 21 CFR 870.4430 - Cardiopulmonary bypass intracardiac suction control. (United States)


    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Cardiopulmonary bypass intracardiac suction....4430 Cardiopulmonary bypass intracardiac suction control. (a) Identification. A cardiopulmonary bypass intracardiac suction control is a device which provides the vacuum and control for a cardiotomy return sucker...

  3. Outcomes after off-pump coronary bypass surgery

    NARCIS (Netherlands)

    Dijk, Diederik van


    The complications associated with in coronary artery bypass surgery (CABG) using cardiopulmonary bypass (CPB) have led to a renewed interest in coronary bypass surgery on the beating heart. The primary objective of the Octopus Study was to compare cognitive outcome between patients randomized to

  4. Advanced Glycation End-Product Accumulation Reduces Vitreous Permeability (United States)

    Lee, On-Tat; Good, Samuel D.; Lamy, Ricardo; Kudisch, Max; Stewart, Jay M.


    Purpose. To evaluate the effect of nonenzymatic cross-linking (glycation) upon the permeability of the vitreous to small- and large-solute diffusion. Methods. Vitreous from freshly excised porcine eyes was treated for 30 minutes with control or 0.01%, 0.1%, or 1% methylglyoxal (MG) solution. The efficacy of the glycation regimen was verified by measuring nonenzymatic cross-link density by fluorescence in the vitreous samples. Resistance to collagenase digestion as well as Nε-(carboxyethyl) lysine (CEL) content were also measured. The permeability coefficient for fluorescein and fluorescein isothiocyanate (FITC)-IgG diffusion through 3 mL of the vitreous samples was determined by using a custom permeability tester. Results. Vitreous cross-linking with MG treatment was confirmed by increased fluorescence, increased CEL concentration, and increased resistance to collagenase digestion. Vitreous glycation resulted in a statistically significant decrease in the permeability coefficient for fluorescein diffusion when either 0.1% or 1% MG solution was used (5.36 ± 5.24 × 10−5 cm s−1, P = 0.04; and 4.03 ± 2.1 × 10−5 cm s−1, P = 0.001; respectively, compared with control, 9.77 ± 5.45 × 10−5 cm s−1). The permeability coefficient for diffusion of FITC-IgG between control (9.9 ± 6.37 × 10−5 cm s−1) and treatment groups was statistically significant at all MG concentrations (0.01% MG: 3.95 ± 3.44 × 10−5 cm s−1, P = 0.003; 0.1% MG: 4.27 ± 1.32 × 10−5 cm s−1, P = 0.004; and 0.1% MG: 3.72 ± 2.49 × 10−5 cm s−1, P = 0.001). Conclusions. Advanced glycation end-product (AGE) accumulation reduces vitreous permeability when glycation is performed in ex vivo porcine vitreous. The permeability change was more pronounced for the larger solute, suggesting a lower threshold for AGE-induced permeability changes to impact the movement of proteins through the vitreous when compared with smaller molecules. PMID:26024075

  5. Effects of Peripheral Neurotensin on Appetite Regulation and Its Role in Gastric Bypass Surgery

    DEFF Research Database (Denmark)

    Ratner, Cecilia; Skov, Louise J; Raida, Zindy


    increased proopiomelanocortin mRNA in the arcuate nucleus. We also investigated the importance of NT for the decreased food intake after gastric bypass surgery in a rat model of Roux-en-Y gastric bypass (RYGB). NT was increased in plasma and in the gastrointestinal tract in RYGB rats, and pharmacological......Neurotensin (NT) is a peptide expressed in the brain and in the gastrointestinal tract. Brain NT inhibits food intake, but the effects of peripheral NT are less investigated. In this study, peripheral NT decreased food intake in both mice and rats, which was abolished by a NT antagonist. Using c...

  6. Nondestructive evaluation for remanent life of aged 12Cr ferrite heat resisting steel by reversible permeability

    Energy Technology Data Exchange (ETDEWEB)

    Ryu, Kwon-Sang, E-mail: [Korea Research Institute of Standards and Science, Centre for Materials Measurement, Doryong Dong, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); Kim, Chung-Seok [Automotive Engineering, Hanyang University, Seoul 133-791 (Korea, Republic of); Baek, Un-bong [Korea Research Institute of Standards and Science, Centre for Materials Measurement, Doryong Dong, Yuseong-Gu, Daejeon 305-340 (Korea, Republic of); Lee, Jong Suk [Gangneung-Wonju National University, Wonju 220-711 (Korea, Republic of)


    We present a magnetic and nondestructive method to evaluate the remanent life of advanced ferritic steel using the value of reversible permeability. The method to measure reversible permeability is based on the theory that the value of reversible permeability is the same differential of the hysteresis loop. The measurement principle is based on the foundation of harmonics voltage induced in a sensing coil using a lock-in amplifier tuned to the frequency of the exciting one. Results obtained for reversible permeability, Vickers hardness, and tensile strength on the aged samples show that the peak interval of reversible permeability, Vickers hardness and tensile strength decrease as aging time increases. We could estimate the remanent life of advanced ferritic steel by using the relationship between the peak interval of reversible permeability and the Larson-Miller parameter, non-destructively. - Highlights: Black-Right-Pointing-Pointer Magnetic, nondestructive evaluation method of remanent life of 12Cr ferritic steel is presented. Black-Right-Pointing-Pointer Peak interval of reversible permeability decreases with the increase of aging time. Black-Right-Pointing-Pointer Mechanical properties decrease with the increase of aging time. Black-Right-Pointing-Pointer Magnetic and mechanical properties are decreased with increase of Larson-Miller parameter. Black-Right-Pointing-Pointer Reversible permeability is nondestructively used to estimate remanent life of 12Cr ferrite steel.

  7. The Permeability of Boolean Sets of Cylinders

    Directory of Open Access Journals (Sweden)

    Willot F.


    Full Text Available Numerical and analytical results on the permeability of Boolean models of randomly-oriented cylinders with circular cross-section are reported. The present work investigates cylinders of prolate (highly-elongated and oblate (nearly flat types. The fluid flows either inside or outside of the cylinders. The Stokes flow is solved using full-fields Fourier-based computations on 3D binarized microstructures. The permeability is given for varying volume fractions of pores. A new upper-bound is derived for the permeability of the Boolean model of oblate cylinders. The behavior of the permeability in the dilute limit is discussed.

  8. Scintigraphic assessment of focal platelet accumulations following infrainguinal bypass surgery in humans

    DEFF Research Database (Denmark)

    Nielsen, Tina G; Hesse, B; Eiberg, J


    Enothelial injury is assumed to be of pathogenetic significance in the development of graft stenoses, which remain a major cause of failure of peripheral bypasses. The aim of this study was to assess endothelial injury related to infrainguinal bypass surgery by indium-111 platelet scintigraphy...... of flow in the graft. Platelet deposition was assessed by gamma-camera images of thigh and crus obtained 4 and/or 24 h after surgery. Areas of focally increased activity were recorded and graded as moderate or intense. In the 24 vein bypasses, a median of two (range 0-5) areas of focally increased...... radioactivity were seen at the proximal anastomosis (n = 21), in the body of the graft (n = 20) or at the distal anastomosis (n = 9). The activity was moderate in 27 cases and intense in 23 cases. Scintigraphic evidence of focal platelet aggregation in vein grafts was not correlated with preoperative...

  9. Vacuum-assisted drainage in cardiopulmonary bypass: advantages and disadvantages. (United States)

    Carvalho Filho, Elio Barreto de; Marson, Fernando Augusto de Lima; Costa, Loredana Nilkenes Gomes da; Antunes, Nilson


    Systematic review of vacuum assisted drainage in cardiopulmonary bypass, demonstrating its advantages and disadvantages, by case reports and evidence about its effects on microcirculation. We conducted a systematic search on the period 1997-2012, in the databases PubMed, Medline, Lilacs and SciELO. Of the 70 selected articles, 26 were included in the review. Although the vacuum assisted drainage has significant potential for complications and requires appropriate technology and professionalism, prevailed in literature reviewed the concept that vacuum assisted drainage contributed in reducing the rate of transfusions, hemodilutions, better operative field, no significant increase in hemolysis, reduced complications surgical, use of lower prime and of smaller diameter cannulas.

  10. Changes in adhesion molecule expression and oxidative burst activity of granulocytes and monocytes during open-heart surgery with cardiopulmonary bypass compared with abdominal surgery

    DEFF Research Database (Denmark)

    Toft, P; Nielsen, C H; Tønnesen, Else Kirstine


    Cardiac and major abdominal surgery are associated with granulocytosis in peripheral blood. The purpose of the present study was to describe the granulocyte and monocyte oxidative burst and the expression of adhesion molecules following cardiac surgery with cardiopulmonary bypass and abdominal...... during cardiopulmonary bypass was observed. The percentage of CD11a-positive granulocytes increased from 30% pre-operatively to 75% following cardiopulmonary bypass, while CD44-positive granulocytes increased from 5% to 13%. Despite the extent of the changes, these were not significant. The oxidative...... to an increased per-operative oxidative burst activity, and the induction of adhesion molecules on granulocytes associated with the cardiopulmonary bypass and surgery. In conclusion, open-heart surgery with cardiopulmonary bypass was associated with a rapid and pronounced activation of leukocytes which may play...

  11. Bypassing primary care clinics for childbirth: a cross-sectional study in the Pwani region, United Republic of Tanzania. (United States)

    Kruk, Margaret E; Hermosilla, Sabrina; Larson, Elysia; Mbaruku, Godfrey M


    To measure the extent, determinants and results of bypassing local primary care clinics for childbirth among women in rural parts of the United Republic of Tanzania. Women were selected in 2012 to complete a structured interview from a full census of all 30076 households in clinic catchment areas in Pwani region. Eligibility was limited to those who had delivered between 6 weeks and 1 year before the interview, were at least 15 years old and lived within the catchment areas. Demographic and delivery care information and opinions on the quality of obstetric care were collected through interviews. Clinic characteristics were collected from staff via questionnaires. Determinants of bypassing (i.e. delivery of the youngest child at a health centre or hospital without provider referral) were analysed using multivariate logistic regression. Bypasser and non-bypasser birth experiences were compared in bivariate analyses. Of 3019 eligible women interviewed (93% response rate), 71.0% (2144) delivered in a health facility; 41.8% (794) were bypassers. Bypassing likelihood increased with primiparity (odds ratio, OR: 2.5; 95% confidence interval, CI: 1.9-3.3) and perceived poor quality at clinics (OR: 1.3; 95% CI: 1.0-1.7) and decreased if clinics recently underwent renovations (OR: 0.39; 95% CI: 0.18-0.84) and/or performed ≥ 4 obstetric signal functions (OR: 0.19; 95% CI: 0.08-0.41). Bypassers reported better quality of care on six of seven quality of care measures. Many pregnant women, especially first-time mothers, choose to bypass local primary care clinics for childbirth. Perceived poor quality of care at clinics was an important reason for bypassing. Primary care is failing to meet the obstetric needs of many women in this rural, low-income setting.

  12. Bypassing BDD Construction for Reliability Analysis

    DEFF Research Database (Denmark)

    Williams, Poul Frederick; Nikolskaia, Macha; Rauzy, Antoine


    In this note, we propose a Boolean Expression Diagram (BED)-based algorithm to compute the minimal p-cuts of boolean reliability models such as fault trees. BEDs make it possible to bypass the Binary Decision Diagram (BDD) construction, which is the main cost of fault tree assessment....

  13. Planetary science: Bypassing the habitable zone (United States)

    Ingersoll, Andrew P.


    In our own solar system, Venus is too hot, Mars is too cold and Earth is just right. Simulations show that making an icy planet habitable is not as simple as melting its ice: many icy bodies swing from too cold to too hot, bypassing just right.

  14. Post-Bypass Extensive Ascites due to Splanchnic Bypass and the Effectiveness of Hyperalimentation Treatment

    Directory of Open Access Journals (Sweden)

    Veysel Temizkan


    Full Text Available Reperfusion edema may develop in the early periods of chronic ischemic tissue reperfusion. Reperfusion edema may be represented after the splanchnic bypass with ascites, abdominal distension, and liver and kidney function impairment. In this article, we are reporting the hyperalimentation treatment and its results for the common ascites and hepatorenal syndrome, after a coeliac and superior mesenteric artery bypass. [Arch Clin Exp Surg 2013; 2(2.000: 124-128

  15. Experimental investigation on the coupled effect of effective stress and gas slippage on the permeability of shale. (United States)

    Yang, Diansen; Wang, Wei; Chen, Weizhong; Wang, Shugang; Wang, Xiaoqiong


    Permeability is one of the most important parameters to evaluate gas production in shale reservoirs. Because shale permeability is extremely low, gas is often used in the laboratory to measure permeability. However, the measured apparent gas permeability is higher than the intrinsic permeability due to the gas slippage effect, which could be even more dominant for materials with nanopores. Increasing gas pressure during tests reduces gas slippage effect, but it also decreases the effective stress which in turn influences the permeability. The coupled effect of gas slippage and effective stress on shale permeability remains unclear. Here we perform laboratory experiments on Longmaxi shale specimens to explore the coupled effect. We use the pressure transient method to measure permeability under different stress and pressure conditions. Our results reveal that the apparent measured permeability is controlled by these two competing effects. With increasing gas pressure, there exists a pressure threshold at which the dominant effect on permeability switches from gas slippage to effective stress. Based on the Klinkenberg model, we propose a new conceptual model that incorporates both competing effects. Combining microstructure analysis, we further discuss the roles of stress, gas pressure and water contents on gas permeability of shale.

  16. Evolution of elderly patients who underwent cardiac surgery with cardiopulmonary bypass

    Directory of Open Access Journals (Sweden)

    Alain Moré Duarte


    Full Text Available Introduction: There is a steady increase in the number of elderly patients with severe cardiovascular diseases who require a surgical procedure to recover some quality of life that allows them a socially meaningful existence, despite the risks.Objectives: To analyze the behavior of elderly patients who underwent cardiac surgery with cardiopulmonary bypass.Method: A descriptive, retrospective, cross-sectional study was conducted with patients over 65 years of age who underwent surgery at the Cardiocentro Ernesto Che Guevara, in Santa Clara, from January 2013 to March 2014.Results: In the study, 73.1% of patients were men; and there was a predominance of subjects between 65 and 70 years of age, accounting for 67.3%. Coronary artery bypass graft was the most prevalent type of surgery and had the longest cardiopulmonary bypass times. Hypertension was present in 98.1% of patients. The most frequent postoperative complications were renal dysfunction and severe low cardiac output, with 44.2% and 34.6% respectively.Conclusions: There was a predominance of men, the age group of 65 to 70 years, hypertension, and patients who underwent coronary artery bypass graft with prolonged cardiopulmonary bypass. Renal dysfunction was the most frequent complication.

  17. Bypass chromatography--design and analysis of an improved strategy for operating batch chromatography processes. (United States)

    Siitonen, Jani; Sainio, Tuomo; Rajendran, Arvind


    The possibility to improve the performance of batch chromatographic separations by using so-called bypass method is analyzed for the first time. In bypass chromatography, only a part of the feed is introduced into the column and purified to purity larger than the desired value. The resulting fractions are then blended with fresh feed to match the given purity constraints. A general approach is presented for designing bypass batch chromatography. Analytical design equations, based on equilibrium theory of chromatography, are presented for the case of binary systems with linear or competitive Langmuir adsorption isotherms under ideal conditions. The approach allows direct calculation of optimal loading and amount of bypass so that arbitrary purity requirements are satisfied without waste streams. It is shown that the bypass strategy enhances productivity of batch chromatography without an increase in the eluent consumption. In the case of a Langmuir isotherm, maximum productivity and minimum eluent consumption are always obtained when the less retained component is collected from the column at 100% purity. In contrast, the optimal purity of the second fraction from the column is typically less than 100% and depends on the purity constraint of the more retained component. In the case of linear isotherms, operation with touching bands is preferred. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. Collaborative Research on the Ultra High Bypass Ratio Engine Cycle to Reduce Noise, Emissions and Fuel Consumption (United States)

    Hughes, Christopher


    A pictorial history of NASA development of advanced engine technologies for reducing environmental emissions and increasing performance from the 1970s to present is presented. The goals of the Subsonic Fixed Wing Program portion of the NASA Fundamental Aeronautics Program are addressed, along with the areas of investigation currently being pursued by the Ultra High Bypass Partnership Element of the Subsonic Fixed Wing Program to meet the goals. Ultra High Bypass cycle research collaboration successes with Pratt & Whitney are presented.

  19. Enhancement and inhibition effects on the corneal permeability of timolol maleate: Polymers, cyclodextrins and chelating agents. (United States)

    Rodríguez, Isabel; Vázquez, José Antonio; Pastrana, Lorenzo; Khutoryanskiy, Vitaliy V


    This study investigates how both bioadhesive polymers (chitosan, hyaluronic acid and alginate) and permeability enhancers (ethylene glycol- bis(2-aminoethylether)- N, N, N', N'- tetraacetic acid (EGTA) and hydroxypropyl-ß-cyclodextrin) influence the permeability of the anti-glaucoma drug timolol maleate through ex vivo bovine corneas. Our results showed that only the permeability enhancers alone were able to increase drug permeability, whereas the polymers significantly reduced drug permeation, and however, they increased the pre-corneal residence of timolol. Ternary systems (polymer-enhancer-drug) showed a reduced drug permeability compared to the polymers alone. Fluorescence microscopy analysis of the epithelium surface confirmed there was no evidence of epithelial disruption caused by these formulations, suggesting that polymer-enhancer interactions reduce drug solubilization and counteract the disruptive effect of the permeability enhancers on the surface of the cornea. Further mucoadhesive tests, revealed a stable interaction of chitosan and hyaluronic acid with the epithelium, while alginate showed poor mucoadhesive properties. The differences in mucoadhesion correlated with the permeability of timolol maleate observed, i.e. formulations containing mucoadhesive polymers showed lower drug permeabilities. The results of the present study indicate polymers acting as an additional barrier towards drug permeability which is even more evident in the presence of permeability enhancers like EGTA and hydroxypropyl-ß-cyclodextrin. Then, this study highlights the need to adequately select additives intended for ocular applications since interactions between them can have opposite results to what expected in terms of drug permeability. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Investigation on the Permeability Evolution of Gypsum Interlayer Under High Temperature and Triaxial Pressure (United States)

    Tao, Meng; Yechao, You; Jie, Chen; Yaoqing, Hu


    The permeability of the surrounding rock is a critical parameter for the designing and assessment of radioactive waste disposal repositories in the rock salt. Generally, in the locations that are chosen for radioactive waste storage, the bedded rock salt is a sedimentary rock that contains NaCl and Na2SO4. Most likely, there are also layers of gypsum ( {CaSO}_{ 4} \\cdot 2 {H}_{ 2} {O)} present in the salt deposit. Radioactive wastes emit a large amount of heat and hydrogen during the process of disposal, which may result in thermal damage of the surrounding rocks and cause a great change in their permeability and tightness. Therefore, it is necessary to investigate the permeability evolution of the gypsum interlayer under high temperature and high pressure in order to evaluate the tightness and security of the nuclear waste repositories in bedded rock salt. In this study, a self-designed rock triaxial testing system by which high temperature and pressure can be applied is used; the μCT225kVFCB micro-CT system is also employed to investigate the permeability and microstructure of gypsum specimens under a constant hydrostatic pressure of 25 MPa, an increasing temperature (ranging from 20 to 650 °C), and a variable inlet gas pressure (1, 2, 4, 6 MPa). The experimental results show: (a) the maximum permeability measured during the whole experiment is less than 10-17 m2, which indicates that the gypsum interlayer has low permeability under high temperature and pressure that meet the requirements for radioactive waste repository. (b) Under the same temperature, the permeability of the gypsum specimen decreases at the beginning and then increases as the pore pressure elevates. When the inlet gas pressure is between 0 and 2 MPa, the Klinkenberg effect is very pronounced. Then, as the pore pressure increases, the movement behavior of gas molecules gradually changes from free motion to forced directional motion. So the role of free movement of gas molecules gradually

  1. Cost-utility analysis comparing laparoscopic vs open aortobifemoral bypass surgery. (United States)

    Krog, Anne Helene; Sahba, Mehdi; Pettersen, Erik M; Wisløff, Torbjørn; Sundhagen, Jon O; Kazmi, Syed Sh


    Laparoscopic aortobifemoral bypass has become an established treatment option for symptomatic aortoiliac obstructive disease at dedicated centers. Minimally invasive surgical techniques like laparoscopic surgery have often been shown to reduce expenses and increase patients' health-related quality of life. The main objective of our study was to measure quality-adjusted life years (QALYs) and costs after totally laparoscopic and open aortobifemoral bypass. This was a within trial analysis in a larger ongoing randomized controlled prospective multicenter trial, Norwegian Laparoscopic Aortic Surgery Trial. Fifty consecutive patients suffering from symptomatic aortoiliac occlusive disease suitable for aortobifemoral bypass surgery were randomized to either totally laparoscopic (n=25) or open surgical procedure (n=25). One patient dropped out of the study before surgery. We measured health-related quality of life using the EuroQol (EQ-5D-5L) questionnaire at 4 different time points, before surgery and for 6 months during follow-up. We calculated the QALYs gained by using the area under the curve for both groups. Costs were calculated based on prices for surgical equipment, vascular prosthesis and hospital stay. We found a significantly higher increase in QALYs after laparoscopic vs open aortobifemoral bypass surgery, with a difference of 0.07 QALYs, (p=0.001) in favor of laparoscopic aortobifemoral bypass. The total cost of surgery, equipment and hospital stay after laparoscopic surgery (9,953 €) was less than open surgery (17,260 €), (p=0.001). Laparoscopic aortobifemoral bypass seems to be cost-effective compared with open surgery, due to an increase in QALYs and lower procedure-related costs.

  2. Gyroid Nanoporous Membranes with Tunable Permeability

    DEFF Research Database (Denmark)

    Li, Li; Schulte, Lars; Clausen, Lydia D.


    Understanding the relevant permeability properties of ultrafiltration membranes is facilitated by using materials and procedures that allow a high degree of control on morphology and chemical composition. Here we present the first study on diffusion permeability through gyroid nanoporous cross-linked...

  3. Intercomparison on measurement of water vapour permeability

    DEFF Research Database (Denmark)

    Hansen, Kurt Kielsgaard

    Three different materials are tested - hard woodfibre board - damp proof course - underlay for roofing The water vapour permeability has been measured according to EN ISO 12572 (2001).......Three different materials are tested - hard woodfibre board - damp proof course - underlay for roofing The water vapour permeability has been measured according to EN ISO 12572 (2001)....

  4. A Negative Permeability Material at Red Light

    DEFF Research Database (Denmark)

    Yuan, Hsiao-Kuan; Chettiar, Uday K.; Cai, Wenshan


    A negative permeability in a periodic array of pairs of thin silver strips is demonstrated experimentally for two distinct samples. The effect of the strip surface roughness on negative permeability is evaluated. The first sample, Sample A, is fabricated of thinner strips with a root mean square ...

  5. Crustal permeability: Introduction to the special issue (United States)

    Ingebritsen, Steven E.; Gleeson, Tom


    The topic of crustal permeability is of broad interest in light of the controlling effect of permeability on diverse geologic processes and also timely in light of the practical challenges associated with emerging technologies such as hydraulic fracturing for oil and gas production (‘fracking’), enhanced geothermal systems, and geologic carbon sequestration. This special issue of Geofluids is also motivated by the historical dichotomy between the hydrogeologic concept of permeability as a static material property that exerts control on fluid flow and the perspective of economic geologists, geophysicists, and crustal petrologists who have long recognized permeability as a dynamic parameter that changes in response to tectonism, fluid production, and geochemical reactions. Issues associated with fracking, enhanced geothermal systems, and geologic carbon sequestration have already begun to promote a constructive dialog between the static and dynamic views of permeability, and here we have made a conscious effort to include both viewpoints. This special issue also focuses on the quantification of permeability, encompassing both direct measurement of permeability in the uppermost crust and inferential permeability estimates, mainly for the deeper crust.

  6. Effect of anionic macromolecules on intestinal permeability of furosemide. (United States)

    Valizadeh, Hadi; Fahimfar, Hadi; Ghanbarzadeh, Saeed; Islambulchilar, Ziba; Zakeri-Milani, Parvin


    Furosemide is an anionic molecule and has very low absorption in gastro intestinal tract. The aim of this study was to investigate the effect of anionic macromolecules on the intestinal permeability of Furosemide. The intestinal permeability of Furosemide was determined using single-pass intestinal perfusion technique in rats. Briefly a jejunal segment of ∼10 cm was isolated and cannulated in both ends for inlet and outlet solution. The perfusate was collected every 10 min and samples were analyzed using the RP-HPLC method. Test samples containing furosemide and two anionic macromolecules, sodium carboxy methyl cellulose and sodium alginate, at different concentrations were used. The obtained data showed that existence of Sodium carboxy methyl cellulose significantly increased the Peff values in all three investigated concentrations (p < 0.05) but sodium alginate only in concentrations <0.1% increased drug permeability. It is concluded that the anionic macromolecules at specific concentrations could alter the permeability of anionic drugs across the biological membranes. Donnan phenomenon and chelating property of macromolecules could be attributed to the observed effect.

  7. Low prevalence of significant carotid artery disease in Iranian patients undergoing elective coronary artery bypass

    Directory of Open Access Journals (Sweden)

    Karimi Fatemeh


    Full Text Available Abstract Background Coronary artery bypass grafting ranks as one of the most frequent operations worldwide. The presence of carotid artery stenosis may increase the stroke rate in the perioperative period. Routine preoperative noninvasive assessment of the carotid arteries are recommended in many institutions to reduce the stroke rate. Methods 271 consecutive patients undergoing coronary artery bypass grafting at Shaheed Madani hospital of Tabriz, Iran (age, 58.5 Y; 73.1% male underwent preoperative ultrasonography for assessment of carotid artery wall thickness. Results Plaque in right common, left common, right internal and left internal carotid arteries was detected in 4.8%, 7.4%, 43.2% and 42.1% of patients respectively. 5 patients (1.8% had significant ( Conclusion Consecutive Iranian patients undergoing elective coronary artery bypass surgery show a very low prevalence of significant carotid artery disease.

  8. Concomitant aorto-right subclavian artery bypass with off-pump coronary artery bypass grafting: a case report. (United States)

    Tazume, Hirokazu; Okamoto, Ken; Fukui, Toshihiro


    Atherosclerotic stenosis of the brachiocephalic artery sometimes occurs in patients with coronary artery disease, and can cause stroke during the perioperative period of coronary artery bypass grafting. We describe the case of a 77-year old male with severe stenosis of the brachiocephalic artery and severe coronary artery disease. He successfully underwent aorto-right subclavian artery bypass that was performed concomitantly with off-pump coronary artery bypass. Concomitant aorto-subclavian artery bypass with off-pump coronary artery bypass grafting is a therapeutic option that minimizes the risk of perioperative stroke in patients with brachiocephalic artery stenosis and coronary artery disease.

  9. Microorganism Removal in Permeable Pavement Parking Lots ... (United States)

    Three types of permeable pavements (pervious concrete, permeable interlocking concrete pavers, and porous asphalt) were monitored at the Edison Environmental Center in Edison, New Jersey for indicator organisms such as fecal coliform, enterococci, and E. coli. Results showed that porous asphalt had much lower concentration in monitored infiltrate compared to pervious concrete and permeable interlocking concrete pavers. Concentrations of monitored organisms in infiltrate from porous asphalt were consistently below the bathing water quality standard. Fecal coliform and enterococci exceeded bathing water quality standards more than 72% and 34% of the time for permeable interlocking concrete pavers and pervious concrete, respectively. Purpose is to evaluate the performance of permeable pavement in removing indicator organisms from infiltrating stormwater runoff.

  10. Modelling of water permeability in cementitious materials

    DEFF Research Database (Denmark)

    Guang, Ye; Lura, Pietro; van Breugel, K.


    This paper presents a network model to predict the permeability of cement paste from a numerical simulation of its microstructure. Based on a linked list pore network structure, the effective hydraulic conductivity is estimated and the fluid flow is calculated according to the Hagen-Poiseuille law....... The pressure gradient at all nodes is calculated with the Gauss elimination method and the absolute permeability of the pore network is calculated directly from Darcy's law. Finally, the permeability model is validated by comparison with direct water permeability measurements. According to this model...... and by the connectivity of the pore structure, regardless of w/c ratio and curing age. The permeability of cement pastes could be predicted reasonably well when a minimum particle size 1 mu m was chosen for the cement....

  11. Permeability measurement and control for epoxy composites (United States)

    Chang, Tsun-Hsu; Tsai, Cheng-Hung; Wong, Wei-Syuan; Chen, Yen-Ren; Chao, Hsien-Wen


    The coupling of the electric and magnetic fields leads to a strong interplay in materials' permittivity and permeability. Here, we proposed a specially designed cavity, called the mu cavity. The mu cavity, consisting of a mushroom structure inside a cylindrical resonator, is exclusively sensitive to permeability, but not to permittivity. It decouples materials' electromagnetic properties and allows an accurate measurement of the permeability. With the help of an epsilon cavity, these two cavities jointly determine the complex permeability and permittivity of the materials at microwave frequencies. Homemade epoxy-based composite materials were prepared and tested. Measurement and manipulation of the permeability and permittivity of the epoxy composites will be shown. The results will be compared with the effective medium theories.

  12. Colloid transport in dual-permeability media. (United States)

    Leij, Feike J; Bradford, Scott A


    It has been widely reported that colloids can travel faster and over longer distances in natural structured porous media than in uniform structureless media used in laboratory studies. The presence of preferential pathways for colloids in the subsurface environment is of concern because of the increased risks for disease caused by microorganisms and colloid-associated contaminants. This study presents a model for colloid transport in dual-permeability media that includes reversible and irreversible retention of colloids and first-order exchange between the aqueous phases of the two regions. The model may also be used to describe transport of other reactive solutes in dual-permeability media. Analytical solutions for colloid concentrations in aqueous and solid phases were obtained using Laplace transformation and matrix decomposition. The solutions proved convenient to assess the effect of model parameters on the colloid distribution. The analytical model was used to describe effluent concentrations for a bromide tracer and 3.2- or 1-μm-colloids that were observed after transport through a composite 10-cm long porous medium made up of a cylindrical lens or core of sand and a surrounding matrix with sand of a different grain size. The tracer data were described very well and realistic estimates were obtained for the pore-water velocity in the two flow domains. An accurate description was also achieved for most colloid breakthrough curves. Dispersivity and retention parameters were typically greater for the larger 3.2-μm-colloids while both reversible and irreversible retention rates tended to be higher for the finer sands than the coarser sand. The relatively small sample size and the complex flow pattern in the composite medium made it difficult to reach definitive conclusions regarding transport parameters for colloid transport. Copyright © 2013 Elsevier B.V. All rights reserved.

  13. SUrgical versus PERcutaneous Bypass : SUPERB-trial; Heparin-bonded endoluminal versus surgical femoro-popliteal bypass: study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    Lensvelt, Mare M. A.; Holewijn, Suzanne; Fritschy, Wilbert M.; Wikkeling, Otmar R. M.; van Walraven, Laurens A.; de Vries, Bas M. Wallis; Zeebregts, Clark J.; Reijnen, Michel M. P. J.


    Background: Endovascular treatment options for the superficial femoral artery are evolving rapidly. For long lesions, the venous femoropopliteal bypass considered to be superior above the prosthetic bypass. An endoluminal bypass, however, may provide equal patency rates compared to the prosthetic

  14. SUrgical versus PERcutaneous Bypass: SUPERB-trial; Heparin-bonded endoluminal versus surgical femoro-popliteal bypass: study protocol for a randomized controlled trial

    NARCIS (Netherlands)

    Lensvelt, M.M.A.; Holewijn, S.; Fritschy, W.M.; Wikkeling, O.R.; Walraven, L.A. van; Wallis de Vries, B.M.; Zeebregts, C.J.A.; Reijnen, M.M.P.J.


    BACKGROUND: Endovascular treatment options for the superficial femoral artery are evolving rapidly. For long lesions, the venous femoropopliteal bypass considered to be superior above the prosthetic bypass. An endoluminal bypass, however, may provide equal patency rates compared to the prosthetic

  15. Simple hyperaemia test as a screening method in the postoperative surveillance of infrainguinal in situ vein bypasses

    DEFF Research Database (Denmark)

    Nielsen, Tina G; Sillesen, H; Schroeder, T V


    OBJECTIVES: To develop a simple protocol for ultrasound Duplex surveillance of infrainguinal vein bypasses. DESIGN: The value of three Doppler waveform parameters, obtained from a single point of the bypass, for identification of stenoses was studied in 91 in situ vein bypasses. Midgraft peak...... systolic velocity (PSV), pulsatility index (PI) and ratio of hyperaemic and resting time-average mean velocities (TAMV), (TAMV ratio = TAMVhyperaemia/TAMVrest) were correlated with the presence and severity of stenoses as assessed by conventional Duplex scanning and ankle-brachial index (ABI) measurements....... The optimal value of the waveform parameters for discrimination between bypasses with and without evidence of stenoses was determined by receiver operating characteristics (ROC) analysis. MAIN RESULTS: Complete Duplex scanning of the entire graft revealed an increase in the peak systolic velocity by a factor...

  16. The permeability of fractured rocks in pressurised volcanic and geothermal systems. (United States)

    Lamur, A; Kendrick, J E; Eggertsson, G H; Wall, R J; Ashworth, J D; Lavallée, Y


    The connectivity of rocks' porous structure and the presence of fractures influence the transfer of fluids in the Earth's crust. Here, we employed laboratory experiments to measure the influence of macro-fractures and effective pressure on the permeability of volcanic rocks with a wide range of initial porosities (1-41 vol. %) comprised of both vesicles and micro-cracks. We used a hand-held permeameter and hydrostatic cell to measure the permeability of intact rock cores at effective pressures up to 30 MPa; we then induced a macro-fracture to each sample using Brazilian tensile tests and measured the permeability of these macro-fractured rocks again. We show that intact rock permeability increases non-linearly with increasing porosity and decreases with increasing effective pressure due to compactional closure of micro-fractures. Imparting a macro-fracture both increases the permeability of rocks and their sensitivity to effective pressure. The magnitude of permeability increase induced by the macro-fracture is more significant for dense rocks. We finally provide a general equation to estimate the permeability of intact and fractured rocks, forming a basis to constrain fluid flow in volcanic and geothermal systems.

  17. Small intestinal permeability to sugars in patients with atopic eczema. (United States)

    Ukabam, S O; Mann, R J; Cooper, B T


    Absorption of lactulose and mannitol was measured in eleven patients with atopic eczema and lactulose/mannitol excretion ratios were calculated. Mean lactulose absorption was increased in the patients with exzema and their excretion ratios were higher than those of controls. There was no correlation between either eczema extent or severity and the excretion ratio. We conclude that small intestinal passive permeability is increased in some patients with atopic eczema.

  18. Hydraulic Permeability of Resorcinol-Formaldehyde Resin

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, Paul Allen [ORNL


    the oxygenated simulant into the feed tank. The dissolved oxygen (DO) concentration of the recirculating simulant was monitored, and the amount of oxygen that reacted with the resin was determined from the change in the DO concentration of the recirculating simulant solution. Prior to hydraulic testing the resin for runs 2 and 3 was covered with the simulant solution and irradiated in a spent fuel element at the Oak Ridge National Laboratory High Flux Isotope Reactor (HFIR). Both batches of resin were irradiated to a total gamma dose of 177 Mrad, but the resin for run 2 reached a maximum temperature during irradiation of 51 C, while the resin for run 3 reached a temperature of 38 C. The different temperatures were the result of the operating status of HFIR at the time of the irradiation and were not part of the test plan; however, the results clearly show the impact of the higher-temperature exposure during irradiation. The flow rate and pressure drop data from the test loop runs show that irradiating the RF resin reduces both the void fraction and the permeability of the resin bed. The mechanism for the reduction in permeability is not clear because irradiation increases the particle size of the resin beads and makes them deform less under pressure. Microscopic examination of the resin beads shows that they are all smooth regular spheres and that irradiation or oxygen uptake did not change the shape of the beads. The resin reacts rapidly with DO in the simulant solution, and the reaction with oxygen reduces the permeability of a bed of new resin by about 10% but has less impact on the permeability of irradiated resin. Irradiation increases the toughness of the resin beads, probably by initiating cross-linking reactions in them. Oxygen uptake reduces the crush strength of both new and irradiated resin; however, the pressures that caused the beads to crush are much higher than would be expected during the operation of an ion exchange column. There was no visible

  19. Gas permeability in polymer- and surfactant-stabilized bubble films. (United States)

    Andreatta, Gaëlle; Lee, Lay-Theng; Lee, Fuk Kay; Benattar, Jean-Jacques


    The gas permeabilities of thin liquid films stabilized by poly(N-isopropylacrylamide) (PNIPAM) and PNIPAM-SDS (sodium dodecyl sulfate) mixtures are studied using the "diminishing bubble" method. The method consists of forming a microbubble on the surface of the polymer solution and measuring the shrinking rates of the bubble and the bubble film as the gas diffuses from the interior to the exterior of the bubble. PNIPAM-stabilized films exhibit variable thicknesses and homogeneities. Interestingly, despite these variable features, the gas permeability of the film is determined principally by the structure of the adsorbed polymer layer that provides an efficient gas barrier with a value of gas permeability coefficient that is comparable to that of an SDS Newton black film. In the presence of SDS, both the film homogeneity and the gas permeability coefficient increase. These changes are related to interactions of PNIPAM with SDS in the solution and at the interface, where coadsorption of the two species forms mixed layers that are stable but that are more porous to gas transfer. The mixed PNIPAM-SDS layers, studied previously for a single water-air interface by neutron reflectivity, are further characterized here in a vertical free-draining film using X-ray reflectivity.

  20. Trench infiltration for managed aquifer recharge to permeable bedrock (United States)

    Heilweil, V.M.; Watt, D.E.


    Managed aquifer recharge to permeable bedrock is increasingly being utilized to enhance resources and maintain sustainable groundwater development practices. One such target is the Navajo Sandstone, an extensive regional aquifer located throughout the Colorado Plateau of the western United States. Spreading-basin and bank-filtration projects along the sandstone outcrop's western edge in southwestern Utah have recently been implemented to meet growth-related water demands. This paper reports on a new cost-effective surface-infiltration technique utilizing trenches for enhancing managed aquifer recharge to permeable bedrock. A 48-day infiltration trench experiment on outcropping Navajo Sandstone was conducted to evaluate this alternative surface-spreading artificial recharge method. Final infiltration rates through the bottom of the trench were about 0.5 m/day. These infiltration rates were an order of magnitude higher than rates from a previous surface-spreading experiment at the same site. The higher rates were likely caused by a combination of factors including the removal of lower permeability soil and surficial caliche deposits, access to open vertical sandstone fractures, a reduction in physical clogging associated with silt and biofilm layers, minimizing viscosity effects by maintaining isothermal conditions, minimizing chemical clogging caused by carbonate mineral precipitation associated with algal photosynthesis, and diminished gas clogging associated with trapped air and biogenic gases. This pilot study illustrates the viability of trench infiltration for enhancing surface spreading of managed aquifer recharge to permeable bedrock. ?? 2010.

  1. Maximizing the right stuff: The trade-off between membrane permeability and selectivity. (United States)

    Park, Ho Bum; Kamcev, Jovan; Robeson, Lloyd M; Elimelech, Menachem; Freeman, Benny D


    Increasing demands for energy-efficient separations in applications ranging from water purification to petroleum refining, chemicals production, and carbon capture have stimulated a vigorous search for novel, high-performance separation membranes. Synthetic membranes suffer a ubiquitous, pernicious trade-off: highly permeable membranes lack selectivity and vice versa. However, materials with both high permeability and high selectivity are beginning to emerge. For example, design features from biological membranes have been applied to break the permeability-selectivity trade-off. We review the basis for the permeability-selectivity trade-off, state-of-the-art approaches to membrane materials design to overcome the trade-off, and factors other than permeability and selectivity that govern membrane performance and, in turn, influence membrane design. Copyright © 2017, American Association for the Advancement of Science.

  2. Taste matters-effects of bypassing oral stimulation on hormone and appetite responses

    NARCIS (Netherlands)

    Spetter, M.S.; Mars, M.; Viergever, M.A.; Graaf, de C.; Smeets, P.A.M.


    The interaction between oral and gastric signals is an important part of food intake regulation. Previous studies suggest that bypassing oral stimulation diminishes the suppression of hunger and increases gastric emptying rate. However, the role of appetite hormones, like cholecystokinin-8 and

  3. Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease

    NARCIS (Netherlands)

    P.W.J.C. Serruys (Patrick); M-C. Morice (Marie-Claude); A.P. Kappetein (Arie Pieter); A. Colombo (Antonio); D.R. Holmes Jr (David); M.J. Mack (Michael); E. Stahle (Elisabeth); T.E. Feldman (Ted); M.J.B.M. van den Brand (Marcel); E.J. Bass (Eric); N. van Dyck (Nic); K. Leadly (Katrin); K.D. Dawkins (Keith); F.W. Mohr (Friedrich)


    textabstractBACKGROUND Percutaneous coronary intervention (PCI) involving drug-eluting stents is increasingly used to treat complex coronary artery disease, although coronary-artery bypass grafting (CABG) has been the treatment of choice historically. Our trial compared PCI and CABG for treating

  4. Should blood flow during cardiopulmonary bypass be individualized more than to body surface area?

    DEFF Research Database (Denmark)

    Thomassen, Sisse Anette; Larsson, A; Andreasen, Jan Jesper

    Blood flow during cardiopulmonary bypass (CPB) is calculated on body surface area (BSA). Increasing comorbidity, age and weight of today's cardiac patients question this calculation as it may not reflect individual metabolic requirement. The hypothesis was that a measured cardiac index (CI) prior...

  5. Expression of adhesion and activation molecules on lymphocytes during open-heart surgery with cardiopulmonary bypass

    DEFF Research Database (Denmark)

    Toft, P; Tønnesen, Else Kirstine; Zülow, I


    Open-heart surgery with cardiopulmonary bypass (CPB) and abdominal surgery are associated with lymphocytopenia. We measured a panel of adhesion and activation molecules on lymphocytes to clarify possible association of CPB with increased expression of these molecules. Eight patients undergoing open...

  6. Age-dependent trends in postoperative mortality and preoperative comorbidity in isolated coronary artery bypass surgery

    DEFF Research Database (Denmark)

    Thorsteinsson, Kristinn; Fonager, Kirsten; Mérie, Charlotte


    OBJECTIVES: An increasing number of octogenarians are being subjected to coronary artery bypass grafting (CABG). The purpose of this study was to examine age-dependent trends in postoperative mortality and preoperative comorbidity over time following CABG. METHODS: All patients who underwent isol...

  7. Bypassing the EPR effect with a nanomedicine harboring a sustained-release function allows better tumor control. (United States)

    Shen, Yao An; Shyu, Ing Luen; Lu, Maggie; He, Chun Lin; Hsu, Yen Mei; Liang, Hsiang Fa; Liu, Chih Peng; Liu, Ren Shyan; Shen, Biing Jiun; Wei, Yau Huei; Chuang, Chi Mu


    The current enhanced permeability and retention (EPR)-based approved nanomedicines have had little impact in terms of prolongation of overall survival in patients with cancer. For example, the two Phase III trials comparing Doxil(®), the first nanomedicine approved by the US Food and Drug Administration, with free doxorubicin did not find an actual translation of the EPR effect into a statistically significant increase in overall survival but did show less cardiotoxicity. In the current work, we used a two-factor factorial experimental design with intraperitoneal versus intravenous delivery and nanomedicine versus free drug as factors to test our hypothesis that regional (intraperitoneal) delivery of nanomedicine may better increase survival when compared with systemic delivery. In this study, we demonstrate that bypassing, rather than exploiting, the EPR effect via intraperitoneal delivery of nanomedicine harboring a sustained-release function demonstrates dual pharmacokinetic advantages, producing more efficient tumor control and suppressing the expression of stemness markers, epithelial-mesenchymal transition, angiogenesis signals, and multidrug resistance in the tumor microenvironment. Metastases to vital organs (eg, lung, liver, and lymphatic system) are also better controlled by intraperitoneal delivery of nanomedicine than by standard systemic delivery of the corresponding free drug. Moreover, the intraperitoneal delivery of nanomedicine has the potential to replace hyperthermic intraperitoneal chemotherapy because it shows equal efficacy and lower toxicity. In terms of efficacy, exploiting the EPR effect may not be the best approach for developing a nanomedicine. Because intraperitoneal chemotherapy is a type of regional chemotherapy, the pharmaceutical industry might consider the regional delivery of nanomedicine as a valid alternative pathway to develop their nanomedicine(s) with the goal of better tumor control in the future.

  8. The Role of Aquaporin 1 Activated by cGMP in Myocardial Edema Caused by Cardiopulmonary Bypass in Sheep

    Directory of Open Access Journals (Sweden)

    Fang-bao Ding


    Full Text Available Background/Aims: Most cardiac procedures involve the use of cardiopulmonary bypass (CPB, which pumps oxygenated blood to the body while the heart and lungs are isolated. CPB can cause profound alterations V in the homeostasis of physiological fluids, which often results in myocardial edema. In our study, we used sheep CPB model of in vivo and in vitro to assess the relationship between cGMP and AQP1 during CPB. Methods: ODQ, a specific inhibitor of soluble guanylate cyclase (sGC, was used to treat the CPB animals or cardiomyocytes. Left ventricular function of each group was determined by pressure-volume system. Water content of myocardial tissue was assessed by dry-wet weight, and cardiomyocytes water permeability was also calculated. The concentration of cGMP was determined by Radioimmunoassay (RIA. mRNA and protein expression of AQP1 were detected by real-time PCR and western blot, respectively. Results: The relative expression level of AQP1 mRNA and protein at each time point (0, 6, 12, 24 or 48 h after CPB was significantly increased (1.18-fold at 12 h, 1.77-fold at 24 h and 2.18-fold at 48h compared with each sham group, the protein expression of AQP1 also showed a rising trend after CPB. The degree of myocardial edema (75.1% at 12 h, 79.3% at 24 h and 81.0% at 48h increased following the CPB surgery. The mRNA expression level of AQP1 was significantly decreased by 39.7% (pin vitro experiments showed the same changing trends as in vivo. Conclusion: cGMP pathway controls water channels and then affects water intake during CPB through an AQP1-mediated pathway.

  9. Control of the permeability of fractures in geothermal rocks (United States)

    Faoro, Igor

    This thesis comprises three journal articles that will be submitted for publication (Journal of Geophysical Research-Solid Earth). Their respective titles are: "Undrained through Drained Evolution of Permeability in Dual Permeability Media" by Igor Faoro, Derek Elsworth and Chris Marone, "Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution" by Igor Faoro, Derek Elsworth Chris Marone; "Linking permeability and mechanical damage for basalt from Mt. Etna volcano (Italy)" by Igor Faoro, Sergio Vinciguerra, Chris Marone and Derek Elsworth. Undrained through Drained Evolution of Permeability in Dual Permeability Media: temporary permeability changes of fractured aquifers subject to earthquakes have been observed and recorded worldwide, but their comprehension still remains a complex issue. In this study we report on flow-through fracture experiments on cracked westerly cores that reproduce, at laboratory scale, those (steps like) permeability changes that have been recorded when earthquakes occur. In particular our experiments show that under specific test boundary conditions, rapid increments of pore pressure induce transient variations of flow rate of the fracture whose peak magnitudes decrease as the variations of the effective stresses increase. We identify that the observed hydraulic behavior of the fracture is due to two principal mechanisms of origin; respectively mechanical (shortening of core) and poro-elastic (radial diffusion of the pore fluid into the matrix of the sample) whose interaction cause respectively an instantaneous opening and then a progressive closure of the fracture. Evolution of Stiffness and Permeability in Fractures Subject to Thermally-and Mechanically-Activated Dissolution: we report the results of radial flow-through experiments conducted on heated samples of Westerly granite. These experiments are performed to examine the influence of thermally and mechanically activated

  10. GERD and acid reduction medication use following gastric bypass and sleeve gastrectomy. (United States)

    Barr, Alex C; Frelich, Matthew J; Bosler, Matthew E; Goldblatt, Matthew I; Gould, Jon C


    Gastroesophageal reflux disease is a common comorbid medical condition of obesity. Laparoscopic sleeve gastrectomy has been associated with de novo and worsening GERD following surgery. For this reason, patients who suffer from GERD and are considering bariatric surgery are often counseled to undergo gastric bypass. Given this practice, we sought to determine acid reduction medication (ARM) utilization in bariatric surgical patients who undergo one of these procedures prior to surgery and at 1 year following surgery. A retrospective review of prospectively maintained data on patients to undergo gastric bypass or sleeve gastrectomy between November 2012 and December 2014 was conducted after IRB approval. ARM utilization and Gastroesophageal Reflux Disease Health-Related Quality of Life (GERD-HRQL) scores [range 0 (no symptoms)-50 (severe GERD)] were compared prior to surgery and at 1 year postoperatively. 334 patients underwent an eligible procedure in the study interval. 147 patients (44 %) had data on both preoperative and 1 year postoperative ARM use (93 gastric bypass and 54 sleeve gastrectomy). ARM utilization prior to surgery in gastric bypass patients did not reach statistical significance when compared to sleeve gastrectomy (40.9 vs. 26 %, p = 0.07). GERD-HRQL scores were greater prior to surgery in gastric bypass patients (GERD-HRQL 8.2 vs. 1.9; p sleeve gastrectomy patients had a significantly higher rate of overall ARM use (48.1 vs. 16.1 %, p sleeve; p = 0.72). Laparoscopic sleeve gastrectomy is associated with a significantly increased likelihood that acid reduction medications will be necessary for GERD symptom control 12 months postoperatively when compared to gastric bypass.

  11. [Robot-assisted Coronary Artery Bypass Grafting]. (United States)

    Ishikawa, Norihiko; Watanabe, Go


    The application for robot-assisted coronary surgery ranges from internal thoracic artery (ITA) harvesting with hand-sewn anastomoses to totally endoscopic coronary artery bypass grafting (TECAB), either on- or off-pump. The bilateral IMA can be harvested with the aid of a surgical robot and then multivessel bypass grafting can follow. Such robot-assisted minimally invasive direct coronary artery bypass grafting is called "ThoraCAB". Surgical robots cannot only endoscopically harvest the ITA but they can also anastomose the coronary artery in TECAB. But TECAB still has the difficulties, such as narrow surgical field in Japanese patients. Both procedures have the significant advantages of minimizing surgical trauma, such as reduced comlications, faster return back to normal activities and being improved cosmesis, and which have resulted in the development of minimally invasive surgery. Robot-assisted cardiac surgery for structural heart disease has been approved by the Ministry of Health, Labour and Welfare (MHLW) since December 2015, however, robot-assisted cardiac surgery for TECAB has not been approved yet in Japan.

  12. Steam by-pass reciprocating rod pump

    Energy Technology Data Exchange (ETDEWEB)

    Waterhouse, B. [Weatherford, Edmonton, AB (Canada)


    This article presented the design details of Weatherford's steam by-pass reciprocating rod rod pump which was designed to work under specific well conditions and individual applications, including Imperial Oil's Cold Lake bitumen recovery project located 230 km northeast of Edmonton, Alberta. Imperial Oil uses a cyclic steam stimulation (CSS) process to enhance bitumen recovery from the Clearwater oil sand reservoir. A typical wellbore reach can be up to 700 m and 80 degrees deviation at a target depth of 455 m TVD. These long well bore reaches along with high bottomhole angles and high produced fluid viscosities complicate the design of the artificial lift, which is essentially a modified conventional API pump. The hold-down section is a friction ring design incorporating stainless steel friction rings to provide positive holding force. The steam by-pass coupling is a reduced-diameter tube fitting between the API pump and the friction ring hold-down section. Three stages of the Imperial Cold Lake operation were described, namely the steam injection stage, soak phase stage and production stage. Typically, the steam by-pass pump is suspended in the tubing for the entire cycle. This presentation reviewed the operating steps of the pump, whose average run time in the field is about 15 months, depending on the potential for scaling or sand influx. tab., figs.

  13. Patient's Perception About Coronary Artery Bypass Grafting

    Directory of Open Access Journals (Sweden)

    Kelminda Maria Bulhões Mendonça


    Full Text Available ABSTRACT OBJECTIVE: The diagnosis of coronary artery disease referred for heart surgery has an important psychological component. The purpose of this study was to access the difficulties experienced by individuals awaiting coronary artery bypass grafting and to determine strategies that facilitate adaptation to a new lifestyle, modified by the disease. METHODS: A qualitative, exploratory study involving patients admitted to a university teaching hospital in the city of Salvador, Bahia, Brazil, awaiting coronary artery bypass grafting. Semi-structured interviews were performed in accordance with a previously defined script based on the study objective. Each transcription was read in its entirety to verify the representativeness, homogeneity and pertinence of the data obtained (pre-analysis, followed by separation of categories of analysis. RESULTS: The descriptions of this study show that patients admitted to the completion of coronary artery bypass grafting experience a wide range of psychological difficulties, considering that surgery acquires interpretations that vary according to individuals' subjectivity. The patients recognized the benefit of being able to discuss their feelings as a means of diminishing their fear and anxiety. CONCLUSION: Helping patients find resources to confront more positively the daily hospitalization is an important aspect for the health care professionals who assist them. This goal can be achieved through modification of the biomedical model of care for a biopsychosocial view. The investment of time and attention is of fundamental importance and aims to overcome existing deficiencies that interfere with the outcome of patients after cardiac surgery.

  14. Vascular permeability and iron deposition biomarkers in longitudinal follow-up of cerebral cavernous malformations. (United States)

    Girard, Romuald; Fam, Maged D; Zeineddine, Hussein A; Tan, Huan; Mikati, Abdul Ghani; Shi, Changbin; Jesselson, Michael; Shenkar, Robert; Wu, Meijing; Cao, Ying; Hobson, Nicholas; Larsson, Henrik B W; Christoforidis, Gregory A; Awad, Issam A


    OBJECTIVE Vascular permeability and iron leakage are central features of cerebral cavernous malformation (CCM) pathogenesis. The authors aimed to correlate prospective clinical behavior of CCM lesions with longitudinal changes in biomarkers of dynamic contrast-enhanced quantitative permeability (DCEQP) and quantitative susceptibility mapping (QSM) assessed by MRI. METHODS Forty-six patients with CCMs underwent 2 or more permeability and/or susceptibility studies in conjunction with baseline and follow-up imaging and clinical surveillance during a mean 12.05 months of follow-up (range 2.4-31.27 months). Based on clinical and imaging features, cases/lesions were classified as stable, unstable, or recovering. Associated and predictive changes in quantitative permeability and susceptibility were investigated. RESULTS Lesional mean permeability and QSM values were not significantly different in stable versus unstable lesions at baseline. Mean lesional permeability in unstable CCMs with lesional bleeding or growth increased significantly (+85.9% change; p = 0.005), while mean permeability in stable and recovering lesions did not significantly change. Mean lesional QSM values significantly increased in unstable lesions (+44.1% change; p = 0.01), decreased slightly with statistical significance in stable lesions (-3.2% change; p = 0.003), and did not significantly change in recovering lesions. Familial cases developing new lesions during the follow-up period showed a higher background brain permeability at baseline (p = 0.001), as well as higher regional permeability (p = 0.003) in the area that would later develop a new lesion as compared with the homologous contralateral brain region. CONCLUSIONS In vivo assessment of vascular permeability and iron deposition on MRI can serve as objective and quantifiable biomarkers of disease activity in CCMs. This may be applied in natural history studies and may help calibrate clinical trials. The 2 techniques are likely applicable in

  15. Diabetic patients have abnormal cerebral autoregulation during cardiopulmonary bypass

    Energy Technology Data Exchange (ETDEWEB)

    Croughwell, N.; Lyth, M.; Quill, T.J.; Newman, M.; Greeley, W.J.; Smith, L.R.; Reves, J.G. (Duke Univ. Medical Center, Durham, NC (USA))


    We tested the hypothesis that insulin-dependent diabetic patients with coronary artery bypass graft surgery experience altered coupling of cerebral blood flow and oxygen consumption. In a study of 23 patients (11 diabetics and 12 age-matched controls), cerebral blood flow was measured using 133Xe clearance during nonpulsatile, alpha-stat blood gas managed cardiopulmonary bypass at the conditions of hypothermia and normothermia. In diabetic patients, the cerebral blood flow at 26.6 +/- 2.42 degrees C was 25.3 +/- 14.34 ml/100 g/min and at 36.9 +/- 0.58 degrees C it was 27.3 +/- 7.40 ml/100 g/min (p = NS). The control patients increased cerebral blood flow from 20.7 +/- 6.78 ml/100 g/min at 28.4 +/- 2.81 degrees C to 37.6 +/- 8.81 ml/100 g/min at 36.5 +/- 0.45 degrees C (p less than or equal to 0.005). The oxygen consumption was calculated from jugular bulb effluent and increased from hypothermic values of 0.52 +/- 0.20 ml/100 g/min in diabetics to 1.26 +/- 0.28 ml/100 g/min (p = 0.001) at normothermia and rose from 0.60 +/- 0.27 to 1.49 +/- 0.35 ml/100 g/min (p = 0.0005) in the controls. Thus, despite temperature-mediated changes in oxygen consumption, diabetic patients did not increase cerebral blood flow as metabolism increased. Arteriovenous oxygen saturation gradients and oxygen extraction across the brain were calculated from arterial and jugular bulb blood samples. The increase in arteriovenous oxygen difference between temperature conditions in diabetic patients and controls was significantly different (p = 0.01). These data reveal that diabetic patients lose cerebral autoregulation during cardiopulmonary bypass and compensate for an imbalance in adequate oxygen delivery by increasing oxygen extraction.

  16. Effect of temperature on sandstone permeability

    DEFF Research Database (Denmark)

    Rosenbrand, Esther; Kjøller, Claus

    with the Kozeny equation and the Klinkenberg procedure. Both methods overestimated the measured brine permeability; this suggests that additional factors, possibly related to clay morphology, contributed to a lower brine permeability. Thermal expansion would have a negligible effect on permeability as estimated...... interaction forces. Quantitative analysis of images, in which mineralogy was mapped based on backscatter electron intensity in combination with energy dispersive X-ray analysis by using the QEMSCAN® system, was used to compare a tested sample to an untested Berea sandstone sample. During the experiment...

  17. Ammonia and urea permeability of mammalian aquaporins

    DEFF Research Database (Denmark)

    Litman, Thomas; Søgaard, Rikke; Zeuthen, Thomas


    The human aquaporins,AQP3,AQP7, AQP8,AQP9, and possibly AQP10, are permeable to ammonia, and AQP7, AQP9, and possibly AQP3, are permeable to urea. In humans, these aquaporins supplement the ammonia transport of the Rhesus (Rh) proteins and the urea transporters (UTs). The mechanism by which...... and 9 are found together with Rh proteins in cells exposed to portal blood coming from the intestine. In the kidney, AQP3 might participate in the excretion of NH(4) (+) in the collecting duct. The interplay between the ammonia-permeable aquaporins and the other types of ammonia- and urea...

  18. Lower leg electrical impedance after distal bypass surgery

    DEFF Research Database (Denmark)

    Belanger, G K; Bolbjerg, M L; Heegaard, N H


    Electrical impedance was determined in 13 patients following distal bypass surgery to evaluate lower leg oedema as reflected by its circumference. Tissue injury was assessed by the plasma concentration of muscle enzymes. After surgery, the volume of the control lower leg increased from 1250 (816......-104) ohms (P surgery was indicated by an increase in total creatine kinase (n = 17) and MB isoenzyme of creatine kinase (n = 8) (P surgery (P ... of troponin I (n = 8). In conclusion, tissue injury was reflected by increases in muscle enzymes in plasma. We found an inverse correlation between lower leg electrical impedance and volume, but the deviation in electrical impedance was approximately twice that of the leg volume. Electrical impedance appears...

  19. Plasma magnesium concentration in patients undergoing coronary artery bypass grafting. (United States)

    Kotlinska-Hasiec, Edyta; Makara-Studzinska, Marta; Czajkowski, Marek; Rzecki, Ziemowit; Olszewski, Krzysztof; Stadnik, Adam; Pilat, Jacek; Rybojad, Beata; Dabrowski, Wojciech


    [b]Introduction[/b]. Magnesium (Mg) plays a crucial role in cell physiology and its deficiency may cause many disorders which often require intensive treatment. The aim of this study was to analyse some factors affecting preoperative plasma Mg concentration in patients undergoing coronary artery bypass grafting (CABG). [b]Materials and method[/b]. Adult patients scheduled for elective CABG with cardio-pulmonary bypass (CPB) under general anaesthesia were studied. Plasma Mg concentration was analysed before surgery in accordance with age, domicile, profession, tobacco smoking and preoperative Mg supplementation. Blood samples were obtained from the radial artery just before the administration of anaesthesia. [b]Results. [/b]150 patients were studied. Mean preoperative plasma Mg concentration was 0.93 ± 0.17 mmol/L; mean concentration in patients - 1.02 ± 0.16; preoperative Mg supplementation was significantly higher than in patients without such supplementation. Moreover, intellectual workers supplemented Mg more frequently and had higher plasma Mg concentration than physical workers. Plasma Mg concentration decreases in elderly patients. Patients living in cities, on average, had the highest plasma Mg concentration. Smokers had significantly lower plasma Mg concentration than non-smokers. [b]Conclusions. [/b]1. Preoperative magnesium supplementation increases its plasma concentration. 2. Intellectual workers frequently supplement magnesium. 3. Smoking cigarettes decreases plasma magnesium concentration.

  20. Low preoperative cholesterol level is a risk factor of sepsis and poor clinical outcome in patients undergoing cardiac surgery with cardiopulmonary bypass. (United States)

    Lagrost, Laurent; Girard, Claude; Grosjean, Sandrine; Masson, David; Deckert, Valérie; Gautier, Thomas; Debomy, Frédérique; Vinault, Sandrine; Jeannin, Aline; Labbé, Jérôme; Bonithon-Kopp, Claire


    Systemic inflammatory response syndrome and sepsis frequently occur after cardiac surgery with cardiopulmonary bypass. The aim of the present study was to investigate whether preoperative cholesterol levels can predict sepsis onset and postoperative complications in patients undergoing cardiac surgery with cardiopulmonary bypass. Prospective observational study. Surgical ICU of a French university hospital. Two hundred and seventeen consecutive patients older than 18 years admitted for planned cardiac surgery with cardiopulmonary bypass. Measurements of plasma blood lipids and inflammation markers before anesthesia induction (baseline), at cardiopulmonary bypass start, at cardiopulmonary bypass end, and 3 and 24 hours after cardiac surgery. Outcomes were compared in systemic inflammatory response syndrome patients with sepsis (n = 15), systemic inflammatory response syndrome patients without sepsis (n = 95), and non-systemic inflammatory response syndrome patients (n = 107). A gradual decrease in plasma cholesterol concentration occurred during surgery with cardiopulmonary bypass but was no longer present after correction for hemodilution. Corrected cholesterol levels were significantly lower at baseline in sepsis patients than in other subgroups, and it remained lower in the sepsis group during and after cardiopulmonary bypass. With regard to sepsis, the discriminatory power of baseline cholesterol was fairly good as indicated by receiver operating characteristic curve analysis (area under the curve, 0.78; 95% CI, 0.72-0.84). The frequency of sepsis progressively decreased with increasing baseline cholesterol level quintiles (18.6% and 0% in the bottom and top quintiles, respectively, p = 0.005). In multivariate analysis, baseline cholesterol levels and cardiopulmonary bypass duration were significant and independent determinants of the 3-hour postcardiopulmonary bypass increase in concentrations of procalcitonin and interleukin-8, but not of interleukin-6. Low

  1. Adaptive Methods for Permeability Estimation and Smart Well Management

    Energy Technology Data Exchange (ETDEWEB)

    Lien, Martha Oekland


    The main focus of this thesis is on adaptive regularization methods. We consider two different applications, the inverse problem of absolute permeability estimation and the optimal control problem of estimating smart well management. Reliable estimates of absolute permeability are crucial in order to develop a mathematical description of an oil reservoir. Due to the nature of most oil reservoirs, mainly indirect measurements are available. In this work, dynamic production data from wells are considered. More specifically, we have investigated into the resolution power of pressure data for permeability estimation. The inversion of production data into permeability estimates constitutes a severely ill-posed problem. Hence, regularization techniques are required. In this work, deterministic regularization based on adaptive zonation is considered, i.e. a solution approach with adaptive multiscale estimation in conjunction with level set estimation is developed for coarse scale permeability estimation. A good mathematical reservoir model is a valuable tool for future production planning. Recent developments within well technology have given us smart wells, which yield increased flexibility in the reservoir management. In this work, we investigate into the problem of finding the optimal smart well management by means of hierarchical regularization techniques based on multiscale parameterization and refinement indicators. The thesis is divided into two main parts, where Part I gives a theoretical background for a collection of research papers that has been written by the candidate in collaboration with others. These constitutes the most important part of the thesis, and are presented in Part II. A brief outline of the thesis follows below. Numerical aspects concerning calculations of derivatives will also be discussed. Based on the introduction to regularization given in Chapter 2, methods for multiscale zonation, i.e. adaptive multiscale estimation and refinement

  2. Effect of rhamnolipids on permeability across Caco-2 cell monolayers. (United States)

    Wallace, Charity J; Medina, Scott H; ElSayed, Mohamed E H


    This report describes the effect of rhamnolipids (RLs), an amphiphilic biosurfactant produced by the bacterium Pseudomonas aeruginosa, on the integrity and permeability across Caco-2 cell monolayers. We measured the trans-epithelial electrical resistance (TEER) and permeability of [(14)C]mannitol across Caco-2 cell monolayers upon incubation with 0.01-5.0% v/v RLs as a function of incubation time (30, 60, 90, and 120 min). We also studied the recovery of RL-treated Caco-2 cell monolayers upon incubation with Kaempferol, which is a natural flavonoid that promotes the assembly of the tight junctions. TEER of Caco-2 cell monolayers incubated with 0.01-5.0% v/v RLs solution dropped to 80-28% of that of untreated cells. Decline in TEER was associated with an increase in [(14)C]mannitol permeability as a function of RLs concentration and incubation time with Caco-2 cells. Incubation of RLs-treated Caco-2 cell monolayers with normal culture medium for 48 h did not restore barrier integrity. Whereas, incubation of a RLs-treated Caco-2 cells with culture medium containing Kaempferol for 24 h restored barrier function indicated by the higher TEER and lower [(14)C]mannitol permeability values. These results show the ability of RLs to modulate the integrity and permeability of Caco-2 cell monolayers in a concentration- and time-dependent fashion, which suggest their potential to function as a non-toxic permeation enhancer.

  3. Rapid and reversible enhancement of blood–brain barrier permeability using lysophosphatidic acid (United States)

    On, Ngoc H; Savant, Sanjot; Toews, Myron; Miller, Donald W


    The present study characterizes the effects of lysophosphatidic acid (LPA) on blood–brain barrier (BBB) permeability focusing specifically on the time of onset, duration, and magnitude of LPA-induced changes in cerebrovascular permeability in the mouse using both magnetic resonance imaging (MRI) and near infrared fluorescence imaging (NIFR). Furthermore, potential application of LPA for enhanced drug delivery to the brain was also examined by measuring the brain accumulation of radiolabeled methotrexate. Exposure of primary cultured brain microvessel endothelial cells (BMECs) to LPA produced concentration-dependent increases in permeability that were completely abolished by clostridium toxin B. Administration of LPA disrupted BBB integrity and enhanced the permeability of small molecular weight marker gadolinium diethylenetriaminepentaacetate (Gd-DTPA) contrast agent, the large molecular weight permeability marker, IRdye800cwPEG, and the P-glycoprotein efflux transporter probe, Rhodamine 800 (R800). The increase in BBB permeability occurred within 3 minutes after LPA injection and barrier integrity was restored within 20 minutes. A decreased response to LPA on large macromolecule BBB permeability was observed after repeated administration. The administration of LPA also resulted in 20-fold enhancement of radiolabeled methotrexate in the brain. These studies indicate that administration of LPA in combination with therapeutic agents may increase drug delivery to the brain. PMID:24045401

  4. Gas permeability of lanthanum oxycarbide targets for the SPES project

    Energy Technology Data Exchange (ETDEWEB)

    Biasetto, L., E-mail: [Università di Padova-Department DTG, Stradella San Nicola 3, I-36100 Vicenza (Italy); Laboratori Nazionali di Legnaro-INFN, V.le dell’Università 2, I-35020 Legnaro (PD) (Italy); Innocentini, M.D.M.; Chacon, W.S. [Curso de Engenharia Química, Universidade de Ribeirão Preto, 14096-900 Ribeirão Preto, SP (Brazil); Corradetti, S.; Carturan, S. [Laboratori Nazionali di Legnaro-INFN, V.le dell’Università 2, I-35020 Legnaro (PD) (Italy); Colombo, P. [Università di Padova, Department DII, via Marzolo 9, I-35131 Padova (Italy); Department of Materials Science and Engineering, The Pennsylvania State University, University Park, PA 16802 (United States); Andrighetto, A. [Laboratori Nazionali di Legnaro-INFN, V.le dell’Università 2, I-35020 Legnaro (PD) (Italy)


    The creation of a porous matrix made of interconnected and permeable paths is a key step for the processing of optimized metal carbide targets in the SPES (Selective Production of Exotic Species) project. Unlike close or non-connected open pores, permeable pores link more efficiently the interior and the surface of target disks, and therefore facilitate the effusion and convection transport mechanisms for a faster extraction of exotic nuclei with short decay times. This work describes the analysis of the interconnected porosity of lanthanum oxycarbide targets through the evaluation of permeability coefficients obtained in argon flow experiments at r