High Glucose Increases Metallothionein Expression in Renal Proximal Tubular Epithelial Cells

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Daisuke Ogawa

2011-01-01

Full Text Available Metallothionein (MT is an intracellular metal-binding, cysteine-rich protein, and is a potent antioxidant that protects cells and tissues from oxidative stress. Although the major isoforms MT-1 and -2 (MT-1/-2 are highly inducible in many tissues, the distribution and role of MT-1/-2 in diabetic nephropathy are poorly understood. In this study, diabetes was induced in adult male rats by streptozotocin, and renal tissues were stained with antibodies for MT-1/-2. MT-1/-2 expression was also evaluated in mProx24 cells, a mouse renal proximal tubular epithelial cell line, stimulated with high glucose medium and pretreated with the antioxidant vitamin E. MT-1/-2 expression was gradually and dramatically increased, mainly in the proximal tubular epithelial cells and to a lesser extent in the podocytes in diabetic rats, but was hardly observed in control rats. MT-1/-2 expression was also increased by high glucose stimulation in mProx24 cells. Because the induction of MT was suppressed by pretreatment with vitamin E, the expression of MT-1/-2 is induced, at least in part, by high glucose-induced oxidative stress. These observations suggest that MT-1/-2 is induced in renal proximal tubular epithelial cells as an antioxidant to protect the kidney from oxidative stress, and may offer a novel therapeutic target against diabetic nephropathy.

CD47 regulates renal tubular epithelial cell self-renewal and proliferation following renal ischemia reperfusion.

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Rogers, Natasha M; Zhang, Zheng J; Wang, Jiao-Jing; Thomson, Angus W; Isenberg, Jeffrey S

2016-08-01

Defects in renal tubular epithelial cell repair contribute to renal ischemia reperfusion injury, cause acute kidney damage, and promote chronic renal disease. The matricellular protein thrombospondin-1 and its receptor CD47 are involved in experimental renal ischemia reperfusion injury, although the role of this interaction in renal recovery is unknown. We found upregulation of self-renewal genes (transcription factors Oct4, Sox2, Klf4 and cMyc) in the kidney of CD47(-/-) mice after ischemia reperfusion injury. Wild-type animals had minimal self-renewal gene expression, both before and after injury. Suggestive of cell autonomy, CD47(-/-) renal tubular epithelial cells were found to increase expression of the self-renewal genes. This correlated with enhanced proliferative capacity compared with cells from wild-type mice. Exogenous thrombospondin-1 inhibited self-renewal gene expression in renal tubular epithelial cells from wild-type but not CD47(-/-) mice, and this was associated with decreased proliferation. Treatment of renal tubular epithelial cells with a CD47 blocking antibody or CD47-targeting small interfering RNA increased expression of some self-renewal transcription factors and promoted cell proliferation. In a syngeneic kidney transplant model, treatment with a CD47 blocking antibody increased self-renewal transcription factor expression, decreased tissue damage, and improved renal function compared with that in control mice. Thus, thrombospondin-1 via CD47 inhibits renal tubular epithelial cell recovery after ischemia reperfusion injury through inhibition of proliferation/self-renewal. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

In vivo antibody-mediated modulation of aminopeptidase A in mouse proximal tubular epithelial cells.

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Mentzel, S; Dijkman, H B; van Son, J P; Wetzels, J F; Assmann, K J

1999-07-01

Aminopeptidase A (APA) is one of the many renal hydrolases. In mouse kidney, APA is predominantly expressed on the brush borders and sparsely on the basolateral membranes of proximal tubular epithelial cells. However, when large amounts of monoclonal antibodies (MAbs) against APA were injected into mice, we observed strong binding of the MAbs to the basolateral membranes, whereas the MAbs bound only transiently to the brush borders of the proximal tubular epithelial cells. In parallel, APA itself disappeared from the brush borders by both endocytosis and shedding, whereas it was increasingly expressed on the basolateral sides. Using ultrastructural immunohistology, we found no evidence for transcellular transport of endocytosed APA to the basolateral side of the proximal tubular epithelial cells. The absence of transcellular transport was confirmed by experiments in which we used a low dose of the MAbs. Such a low dose did not result in binding of the MAbs to the brush borders and had no effect on the presence of APA in the brush borders of the proximal tubular epithelial cells. In these experiments we still could observe binding of the MAbs to the basolateral membranes in parallel with the local appearance of APA. In addition, treatment of mice with chlorpromazine, a calmodulin antagonist that interferes with cytoskeletal function, largely inhibited the MAb-induced modulation of APA. Our studies suggest that injection of MAbs to APA specifically interrupts the normal intracellular traffic of this enzyme in proximal tubular epithelial cells. This intracellular transport is dependent on the action of cytoskeletal proteins.

Tubular inverse opal scaffolds for biomimetic vessels

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Zhao, Ze; Wang, Jie; Lu, Jie; Yu, Yunru; Fu, Fanfan; Wang, Huan; Liu, Yuxiao; Zhao, Yuanjin; Gu, Zhongze

2016-07-01

There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially oriented elliptical pattern microstructures on their surfaces. It is demonstrated that these tailored tubular scaffolds can effectively make endothelial cells to form an integrated hollow tubular structure on their inner surface and induce smooth muscle cells to form a circumferential orientation on their outer surface. These features of our tubular scaffolds make them highly promising for the construction of biomimetic blood vessels.There is a clinical need for tissue-engineered blood vessels that can be used to replace or bypass damaged arteries. The success of such grafts depends strongly on their ability to mimic native arteries; however, currently available artificial vessels are restricted by their complex processing, controversial integrity, or uncontrollable cell location and orientation. Here, we present new tubular scaffolds with specific surface microstructures for structural vessel mimicry. The tubular scaffolds are fabricated by rotationally expanding three-dimensional tubular inverse opals that are replicated from colloidal crystal templates in capillaries. Because of the ordered porous structure of the inverse opals, the expanded tubular scaffolds are imparted with circumferentially

Overendocytosis of gold nanoparticles increases autophagy and apoptosis in hypoxic human renal proximal tubular cells

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Ding F

2014-09-01

Full Text Available Fengan Ding,1 Yiping Li,1 Jing Liu,1 Lei Liu,1 Wenmin Yu,1 Zhi Wang,1 Haifeng Ni,2 Bicheng Liu,2 Pingsheng Chen1,2 1School of Medicine, Southeast University, Nanjing, People’s Republic of China; 2Institute of Nephrology, The Affiliated Zhongda Hospital, Southeast University, Nanjing, People’s Republic of China Background: Gold nanoparticles (GNPs can potentially be used in biomedical fields ranging from therapeutics to diagnostics, and their use will result in increased human exposure. Many studies have demonstrated that GNPs can be deposited in the kidneys, particularly in renal tubular epithelial cells. Chronic hypoxic is inevitable in chronic kidney diseases, and it results in renal tubular epithelial cells that are susceptible to different types of injuries. However, the understanding of the interactions between GNPs and hypoxic renal tubular epithelial cells is still rudimentary. In the present study, we characterized the cytotoxic effects of GNPs in hypoxic renal tubular epithelial cells.Results: Both 5 nm and 13 nm GNPs were synthesized and characterized using various biophysical methods, including transmission electron microscopy, dynamic light scattering, and ultraviolet–visible spectrophotometry. We detected the cytotoxicity of 5 and 13 nm GNPs (0, 1, 25, and 50 nM to human renal proximal tubular cells (HK-2 by Cell Counting Kit-8 assay and lactate dehydrogenase release assay, but we just found the toxic effect in the 5 nm GNP-treated cells at 50 nM dose under hypoxic condition. Furthermore, the transmission electron microscopy images revealed that GNPs were either localized in vesicles or free in the lysosomes in 5 nm GNPs-treated HK-2 cells, and the cellular uptake of the GNPs in the hypoxic cells was significantly higher than that in normoxic cells. In normoxic HK-2 cells, 5 nm GNPs (50 nM treatment could cause autophagy and cell survival. However, in hypoxic conditions, the GNP exposure at the same condition led to the

Gremlin Activates the Smad Pathway Linked to Epithelial Mesenchymal Transdifferentiation in Cultured Tubular Epithelial Cells

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Raquel Rodrigues-Diez

2014-01-01

Full Text Available Gremlin is a developmental gene upregulated in human chronic kidney disease and in renal cells in response to transforming growth factor-β (TGF-β. Epithelial mesenchymal transition (EMT is one process involved in renal fibrosis. In tubular epithelial cells we have recently described that Gremlin induces EMT and acts as a downstream TGF-β mediator. Our aim was to investigate whether Gremlin participates in EMT by the regulation of the Smad pathway. Stimulation of human tubular epithelial cells (HK2 with Gremlin caused an early activation of the Smad signaling pathway (Smad 2/3 phosphorylation, nuclear translocation, and Smad-dependent gene transcription. The blockade of TGF-β, by a neutralizing antibody against active TGF-β, did not modify Gremlin-induced early Smad activation. These data show that Gremlin directly, by a TGF-β independent process, activates the Smad pathway. In tubular epithelial cells long-term incubation with Gremlin increased TGF-β production and caused a sustained Smad activation and a phenotype conversion into myofibroblasts-like cells. Smad 7 overexpression, which blocks Smad 2/3 activation, diminished EMT changes observed in Gremlin-transfected tubuloepithelial cells. TGF-β neutralization also diminished Gremlin-induced EMT changes. In conclusion, we propose that Gremlin could participate in renal fibrosis by inducing EMT in tubular epithelial cells through activation of Smad pathway and induction of TGF-β.

Cisplatin toxicity reduced in human cultured renal tubular cells by oxygen pretreatment.

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Kaeidi, Ayat; Rasoulian, Bahram; Hajializadeh, Zahra; Pourkhodadad, Soheila; Rezaei, Maryam

2013-01-01

Cisplatin is an effective and widely used chemotherapy agent and its side effects, particularly nephrotoxicity, limit its usage and related platinum-based drugs. Cisplatin nephrotoxicity is mainly due to extremely increase in reactive oxygen species (ROS) generation leading to kidney tubular cell death. Preconditioning with oxidative stress has been demonstrated to stimulate the cellular adaptation to subsequent severe oxidative stress. Short term oxygen pre-exposure as a mild oxidative stress may enhance some endogenous defense mechanisms, so its effect on Cisplatin induced cell death was investigated in present research. We studied the effects of hyperoxic environment pre-exposure on Cisplatin toxicity in an in-vitro model of cultured human embryonic tubular epithelial cells (AD293). Viability of AD293 cells, as evaluated by MTT-assay, was affected by Cisplatin in a time (1-4 h) dependent model. Biochemical markers of cell apoptosis were evaluated using immunoblotting. Pretreatment with nearly pure oxygen (≥90%) for 2 h significantly reduced the level of cell damage. Activated caspase 3 and Bax/Bcl-2 ratio were significantly increased in Cisplatin-treated cells. Oxygen pretreatment inhibited caspase 3 activation and decreased Bax/Bcl-2 ratio. Oxygen pre-treatment itself not showed any cytotoxicity in exposure times up to 3 h. Our data indicate that hyperoxic preconditioning reduces Cisplatin toxicity in cultured human tubular epithelial cells. The exact mechanism of protection is unclear, though enhancement of some endogenous defense mechanisms and subsequently scavenging of free oxygen radicals may play an important role.

A case of Fanconi syndrome accompanied by crystal depositions in tubular cells in a patient with multiple myeloma

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Do Hee Kim

2014-06-01

Full Text Available Fanconi syndrome (FS is a rare condition that is characterized by defects in the proximal tubular function. A 48-year-old woman was admitted for evaluation of proteinuria. The patient showed normal anion gap acidosis, normoglycemic glycosuria, hypophosphatemia, and hypouricemia. Thus, her condition was compatible with FS. The M peak was found behind the beta globulin region in urine protein electrophoresis. Upon bone marrow examination, we found that 24% of cells were CD138+ plasma cells with kappa restriction. From a kidney biopsy, we found crystalline inclusions within proximal tubular epithelial cells. Thereafter, she was diagnosed with FS accompanied by multiple myeloma. The patient received chemotherapy and autologous stem cell transplantation, and obtained very good partial hematologic response. However, proximal tubular dysfunction was persistent until 1 year after autologous stem cell transplantation. In short, we report a case of FS accompanied by multiple myeloma, demonstrating crystalline inclusion in proximal tubular cells on kidney biopsy.

Isolation and characterization of a primary proximal tubular epithelial cell model from human kidney by CD10/CD13 double labeling.

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Cynthia Van der Hauwaert

Full Text Available Renal proximal tubular epithelial cells play a central role in renal physiology and are among the cell types most sensitive to ischemia and xenobiotic nephrotoxicity. In order to investigate the molecular and cellular mechanisms underlying the pathophysiology of kidney injuries, a stable and well-characterized primary culture model of proximal tubular cells is required. An existing model of proximal tubular cells is hampered by the cellular heterogeneity of kidney; a method based on cell sorting for specific markers must therefore be developed. In this study, we present a primary culture model based on the mechanical and enzymatic dissociation of healthy tissue obtained from nephrectomy specimens. Renal epithelial cells were sorted using co-labeling for CD10 and CD13, two renal proximal tubular epithelial markers, by flow cytometry. Their purity, phenotypic stability and functional properties were evaluated over several passages. Our results demonstrate that CD10/CD13 double-positive cells constitute a pure, functional and stable proximal tubular epithelial cell population that displays proximal tubule markers and epithelial characteristics over the long term, whereas cells positive for either CD10 or CD13 alone appear to be heterogeneous. In conclusion, this study describes a method for establishing a robust renal proximal tubular epithelial cell model suitable for further experimentation.

Evaluation of cell viability and functionality in vessel-like bioprintable cell-laden tubular channels.

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Yu, Yin; Zhang, Yahui; Martin, James A; Ozbolat, Ibrahim T

2013-09-01

Organ printing is a novel concept recently introduced in developing artificial three-dimensional organs to bridge the gap between transplantation needs and organ shortage. One of the major challenges is inclusion of blood-vessellike channels between layers to support cell viability, postprinting functionality in terms of nutrient transport, and waste removal. In this research, we developed a novel and effective method to print tubular channels encapsulating cells in alginate to mimic the natural vascular system. An experimental investigation into the influence on cartilage progenitor cell (CPCs) survival, and the function of printing parameters during and after the printing process were presented. CPC functionality was evaluated by checking tissue-specific genetic marker expression and extracellular matrix production. Our results demonstrated the capability of direct fabrication of cell-laden tubular channels by our newly designed coaxial nozzle assembly and revealed that the bioprinting process could induce quantifiable cell death due to changes in dispensing pressure, coaxial nozzle geometry, and biomaterial concentration. Cells were able to recover during incubation, as well as to undergo differentiation with high-level cartilage-associated gene expression. These findings may not only help optimize our system but also can be applied to biomanufacturing of 3D functional cellular tissue engineering constructs for various organ systems.

Mechanistic modelling of a cathode-supported tubular solid oxide fuel cell

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Suwanwarangkul, R.; Croiset, E.; Pritzker, M. D.; Fowler, M. W.; Douglas, P. L.; Entchev, E.

A two-dimensional mechanistic model of a tubular solid oxide fuel cell (SOFC) considering momentum, energy, mass and charge transport is developed. The model geometry of a single cell comprises an air-preheating tube, air channel, fuel channel, anode, cathode and electrolyte layers. The heat radiation between cell and air-preheating tube is also incorporated into the model. This allows the model to predict heat transfer between the cell and air-preheating tube accurately. The model is validated and shows good agreement with literature data. It is anticipated that this model can be used to help develop efficient fuel cell designs and set operating variables under practical conditions. The transport phenomena inside the cell, including gas flow behaviour, temperature, overpotential, current density and species concentration, are analysed and discussed in detail. Fuel and air velocities are found to vary along flow passages depending on the local temperature and species concentrations. This model demonstrates the importance of incorporating heat radiation into a tubular SOFC model. Furthermore, the model shows that the overall cell performance is limited by O 2 diffusion through the thick porous cathode and points to the development of new cathode materials and designs being important avenues to enhance cell performance.

Proliferative capacity of stem/progenitor-like cells in the kidney may associate with the outcome of patients with acute tubular necrosis.

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Ye, Youxin; Wang, Bingyin; Jiang, Xinxin; Hu, Weiming; Feng, Jian; Li, Hua; Jin, Mei; Ying, Yingjuan; Wang, Wenjuan; Mao, Xiaoou; Jin, Kunlin

2011-08-01

Animal studies indicate that adult renal stem/progenitor cells can undergo rapid proliferation in response to renal injury, but whether the same is true in humans is largely unknown. To examine the profile of renal stem/progenitor cells responsible for acute tubular necrosis in human kidney, double and triple immunostaining was performed using proliferative marker and stem/progenitor protein markers on sections from 10 kidneys with acute tubular necrosis and 4 normal adult kidneys. The immunopositive cells were recorded using 2-photon confocal laser scanning microscopy. We found that dividing cells were present in the tubules of the cortex and medulla, as well as the glomerulus in normal human kidney. Proliferative cells in the parietal layer of Bowman capsule expressed CD133, and dividing cells in the tubules expressed immature cell protein markers paired box gene 2, vimentin, and nestin. After acute tubular necrosis, Ki67-positive cells in the cortex tubules significantly increased compared with normal adult kidney. These Ki67-positive cells expressed CD133 and paired box gene 2, but not the cell death marker, activated caspase-3. In addition, the number of dividing cells increased significantly in patients with acute tubular necrosis who subsequently recovered, compared with patients with acute tubular necrosis who consequently developed protracted acute tubular necrosis or died. Our data suggest that renal stem/progenitor cells may reside not only in the parietal layer of Bowman capsule but also in the cortex and medulla in normal human kidney, and the proliferative capacity of renal stem/progenitor cells after acute tubular necrosis may be an important determinant of a patient's outcome. Copyright © 2011 Elsevier Inc. All rights reserved.

Expanding the histologic spectrum of mucinous tubular and spindle cell carcinoma of the kidney.

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Fine, Samson W; Argani, Pedram; DeMarzo, Angelo M; Delahunt, Brett; Sebo, Thomas J; Reuter, Victor E; Epstein, Jonathan I

2006-12-01

Mucinous tubular and spindle cell carcinomas (MTSCs) are polymorphic neoplasms characterized by small, elongated tubules lined by cuboidal cells and/or cords of spindled cells separated by pale mucinous stroma. Nonclassic morphologic variants and features of MTSC have not been well studied. We identified 17 previously unreported MTSCs from Surgical Pathology and consultative files of the authors and their respective institutions and studied their morphologic features. A total of 10/17 cases were considered "classic," as described above, with 5/10 showing at least focal (20% to 50%) tubular predominance without apparent mucinous matrix. Alcian blue staining revealed abundant (>50%) mucin in all classic cases. Seven of 17 MTSCs were classified as "mucin-poor," with little to no extracellular mucin appreciable by hematoxylin and eosin. Four of these cases showed equal tubular and spindled morphology, 2 cases showed spindle cell predominance (70%; 95%), and 1 case showed tubular predominance (90%). In 5/7 mucin-poor cases, staining for Alcian blue revealed scant (<10%) mucin in cellular areas with the other 2 cases having 30% mucin. Unusual histologic features identified in the 17 cases were: foamy macrophages (n=8), papillations/well formed papillae (n=6/n=1), focal clear cells in tubules (n=3), necrosis (n=3), oncocytic tubules (n=2; 40%, 5%), numerous small vacuoles (n=2), heterotopic bone (n=1), psammomatous calcification (n=1), and nodular growth with lymphocytic cuffing (n=1). An exceptional case contained a well-circumscribed, HMB45-positive angiomyolipoma within the MTSC. MTSCs may be "mucin-poor" and show a marked predominance of either of its principal morphologic components, which coupled with the presence of other unusual features such as clear cells, papillations, foamy macrophages, and necrosis, may mimic other forms of renal cell carcinoma. Pathologists must be aware of the spectrum of histologic findings within MTSCs to ensure their accurate diagnosis.

Defective proximal tubular function in a patient with I-cell disease.

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Bocca, G.; Monnens, L.A.H.

2003-01-01

A girl with a proven diagnosis of I-cell disease is presented. Proximal tubular dysfunction was characterized by increased excretion of low molecular proteins, aminoaciduria, hyperphosphaturia, and high/slightly increased urinary calcium. The concentration of 1,25-dihydroxycalciferol in serum was

Exosome production and its regulation of EGFR during wound healing in renal tubular cells.

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Zhou, Xiangjun; Zhang, Wei; Yao, Qisheng; Zhang, Hao; Dong, Guie; Zhang, Ming; Liu, Yutao; Chen, Jian-Kang; Dong, Zheng

2017-06-01

Kidney repair following injury involves the reconstitution of a structurally and functionally intact tubular epithelium. Growth factors and their receptors, such as EGFR, are important in the repair of renal tubules. Exosomes are cell-produced small (~100 nm in diameter) vesicles that contain and transfer proteins, lipids, RNAs, and DNAs between cells. In this study, we examined the relationship between exosome production and EGFR activation and the potential role of exosome in wound healing. EGFR activation occurred shortly after scratch wounding in renal tubular cells. Wound repair after scratching was significantly promoted by EGF and suppressed by EGFR inhibitor gefitinib. Interestingly, scratch wounding induced a significant increase of exosome production. The exosome production was decreased by EGF and increased by gefitinib, suggesting a suppressive role of EGFR signaling in exosome production. Conversely, inhibition of exosome release by GW4869 and manumycin A markedly increased EGFR activation and promoted wound healing. Moreover, exosomes derived from scratch-wounding cells could inhibit wound healing. Collectively, the results indicate that wound healing in renal tubular cells is associated with EGFR activation and exosome production. Although EGFR activation promotes wound healing, released exosomes may antagonize EGFR activation and wound healing. Copyright © 2017 the American Physiological Society.

Hypertrophy of proximal tubular epithelial cells induced by low pH in vitro is independent of ammoniagenesis.

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Bevington, A; Millwater, C J; Walls, J

1994-01-01

Metabolic acidosis can lead to tubular hypertrophy in vivo. This is thought to arise from stimulation of renal production of ammonia, a known hypertrophic agent. To examine this effect in vitro, confluent opossum (OK) proximal tubular epithelial cells were cultured at acidic pH (7.21 +/- 0.02) or at control pH (7.37 +/- 0.01) for 4 days. Protein content was 9% higher at acidic pH whereas DNA content was unaffected. The resulting increase in mean cell size (protein/DNA ratio) was 10% but correlated inversely with the mass of cells in control wells, varying from +48% at low cell mass to -14% at high cell mass. In contrast, low pH decreased 3H-thymidine incorporation by 9%. However, ammonia production was unaffected. These changes in protein/DNA ratio and 3H-thymidine incorporation cannot therefore be attributed to acid-induced ammoniagenesis and imply that low pH exerts a more direct effect on tubular cell growth than previously envisaged.

The fine structure of sheep myocardial cells; sarcolemmal invaginations and the transverse tubular system.

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SIMPSON, F O; OERTELIS, S J

1962-01-01

An electron microscope study of sheep myocardial cells has demonstrated the presence of a transverse tubular system, apparently forming a network across the cell at each Z band level. The walls of these tubules resemble the sarcolemma in consisting of two dense layers-plasma membrane and basement menbrane; continuity of the tubule walls with the sarcolemma can be seen when longitudinal sections of a cell are obtained between two subsarcolemmal myofibrils and at the same time perpendicular to the cell surface. The demonstration of communication between the lumen of the transverse tubular system and the extracellular space appears to be more definite in this study than in any work hitherto published. It provides anatomical evidence of a possible direct pathway for transmission of the activating impulse from the sarcolemma to the myofibril Z bands.

Renal Impairment with Sublethal Tubular Cell Injury in a Chronic Liver Disease Mouse Model.

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Tokiko Ishida

Full Text Available The pathogenesis of renal impairment in chronic liver diseases (CLDs has been primarily studied in the advanced stages of hepatic injury. Meanwhile, the pathology of renal impairment in the early phase of CLDs is poorly understood, and animal models to elucidate its mechanisms are needed. Thus, we investigated whether an existing mouse model of CLD induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC shows renal impairment in the early phase. Renal injury markers, renal histology (including immunohistochemistry for tubular injury markers and transmission electron microscopy, autophagy, and oxidative stress were studied longitudinally in DDC- and standard diet-fed BALB/c mice. Slight but significant renal dysfunction was evident in DDC-fed mice from the early phase. Meanwhile, histological examinations of the kidneys with routine light microscopy did not show definitive morphological findings, and electron microscopic analyses were required to detect limited injuries such as loss of brush border microvilli and mitochondrial deformities. Limited injuries have been recently designated as sublethal tubular cell injury. As humans with renal impairment, either with or without CLD, often show almost normal tubules, sublethal injury has been of particular interest. In this study, the injuries were associated with mitochondrial aberrations and oxidative stress, a possible mechanism for sublethal injury. Intriguingly, two defense mechanisms were associated with this injury that prevent it from progressing to apparent cell death: autophagy and single-cell extrusion with regeneration. Furthermore, the renal impairment of this model progressed to chronic kidney disease with interstitial fibrosis after long-term DDC feeding. These findings indicated that DDC induces renal impairment with sublethal tubular cell injury from the early phase, leading to chronic kidney disease. Importantly, this CLD mouse model could be useful for studying the

A paracrine mechanism involving renal tubular cells, adipocytes and macrophages promotes kidney stone formation in a simulated metabolic syndrome environment.

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Zuo, Li; Tozawa, Keiichi; Okada, Atsushi; Yasui, Takahiro; Taguchi, Kazumi; Ito, Yasuhiko; Hirose, Yasuhiko; Fujii, Yasuhiro; Niimi, Kazuhiro; Hamamoto, Shuzo; Ando, Ryosuke; Itoh, Yasunori; Zou, Jiangang; Kohri, Kenjiro

2014-06-01

We developed an in vitro system composed of renal tubular cells, adipocytes and macrophages to simulate metabolic syndrome conditions. We investigated the molecular communication mechanism of these cells and their involvement in kidney stone formation. Mouse renal tubular cells (M-1) were cocultured with adipocytes (3T3-L1) and/or macrophages (RAW264.7). Calcium oxalate monohydrate crystals were exposed to M-1 cells after 48-hour coculture and the number of calcium oxalate monohydrate crystals adherent to the cells was quantified. The expression of cocultured medium and M-1 cell inflammatory factors was analyzed by enzyme-linked immunosorbent assay and quantitative polymerase chain reaction, respectively. The inflammatory markers MCP-1, OPN and TNF-α were markedly up-regulated in cocultured M-1 cells. OPN expression increased in M-1 cells cocultured with RAW264.7 cells while MCP-1 and TNF-α were over expressed in M-1 cells cocultured with 3T3-L1 cells. Coculturing M-1 cells simultaneously with 3T3-L1 and RAW264.7 cells resulted in a significant increase in calcium oxalate monohydrate crystal adherence to M-1 cells. Inflammatory cytokine changes were induced by coculturing renal tubular cells with adipocytes and/or macrophages without direct contact, indicating that crosstalk between adipocytes/macrophages and renal tubular cells was mediated by soluble factors. The susceptibility to urolithiasis of patients with metabolic syndrome might be due to aggravated inflammation of renal tubular cells triggered by a paracrine mechanism involving these 3 cell types. Copyright © 2014 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

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Matsui, Takanori [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, Kurume (Japan); Yamagishi, Sho-ichi, E-mail: shoichi@med.kurume-u.ac.jp [Department of Pathophysiology and Therapeutics of Diabetic Vascular Complications, Kurume University School of Medicine, Kurume (Japan); Takeuchi, Masayoshi [Department of Pathophysiological Science, Faculty of Pharmaceutical Science, Hokuriku University, Kanazawa (Japan); Ueda, Seiji; Fukami, Kei; Okuda, Seiya [Department of Medicine, Kurume University School of Medicine, Kurume (Japan)

2010-07-23

Research highlights: {yields} Nifedipine inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma}. {yields} GW9662 treatment alone increased RAGE mRNA levels in tubular cells. {yields} Nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-{beta} gene expression in tubular cells, all of which were blocked by GW9662. -- Abstract: There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-{gamma} (PPAR{gamma}). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-{kappa}B activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression

Nifedipine inhibits advanced glycation end products (AGEs) and their receptor (RAGE) interaction-mediated proximal tubular cell injury via peroxisome proliferator-activated receptor-gamma activation

International Nuclear Information System (INIS)

Matsui, Takanori; Yamagishi, Sho-ichi; Takeuchi, Masayoshi; Ueda, Seiji; Fukami, Kei; Okuda, Seiya

2010-01-01

Research highlights: → Nifedipine inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by GW9662, an inhibitor of peroxisome proliferator-activated receptor-γ. → GW9662 treatment alone increased RAGE mRNA levels in tubular cells. → Nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-κB activation and increases in intercellular adhesion molecule-1 and transforming growth factor-β gene expression in tubular cells, all of which were blocked by GW9662. -- Abstract: There is a growing body of evidence that advanced glycation end products (AGEs) and their receptor (RAGE) interaction evokes oxidative stress generation and subsequently elicits inflammatory and fibrogenic reactions, thereby contributing to the development and progression of diabetic nephropathy. We have previously found that nifedipine, a calcium-channel blocker (CCB), inhibits the AGE-induced mesangial cell damage in vitro. However, effects of nifedipine on proximal tubular cell injury remain unknown. We examined here whether and how nifedipine blocked the AGE-induced tubular cell damage. Nifedipine, but not amlodipine, a control CCB, inhibited the AGE-induced up-regulation of RAGE mRNA levels in tubular cells, which was prevented by the simultaneous treatment of GW9662, an inhibitor of peroxisome proliferator-activated receptor-γ (PPARγ). GW9662 treatment alone was found to increase RAGE mRNA levels in tubular cells. Further, nifedipine inhibited the AGE-induced reactive oxygen species generation, NF-κB activation and increases in intercellular adhesion molecule-1 and transforming growth factor-beta gene expression in tubular cells, all of which were blocked by GW9662. Our present study provides a unique beneficial aspect of nifedipine on diabetic nephropathy; it could work as an anti-oxidative and anti-inflammatory agent against AGEs in tubular cells by suppressing RAGE expression via PPARγ activation.

Endocytosis of wheat germ agglutinin binding sites from the cell surface into a tubular endosomal network.

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Raub, T J; Koroly, M J; Roberts, R M

1990-04-01

By using fluorescence and electron microscopy, the endocytic pathway encountered by cell surface components after they had bound wheat germ agglutinin (WGA) was visualized. The majority of these components are thought to consist of sialylated glycoproteins (HMWAG) that represent a subpopulation of the total cell surface proteins but most of the externally disposed plasma membrane proteins of the cell. Examination of semi-thin sections by medium- and high-voltage electron microscopy revealed the three-dimensional organization of vesicular and tubular endosomes. Binding of either fluorescein isothiocyanate-, horseradish peroxidase-, or ferritin-conjugated WGA to cells at 4 degrees C showed that the HMWAG were distributed uniformly over the cell surface. Warming of surface-labeled cells to 37 degrees C resulted in the endocytosis of WGA into peripheral endosomes via invagination of regions of both coated and uncoated membrane. The peripheral endosome appeared as isolated complexes comprising a vesicular element (300-400 nm diam.) surrounded by and continuous with tubular cisternae (45-60 nm diam.), which did not interconnect the endosomes. After 30 min or more label also became localized in a network of anastomosing tubules (45-60 nm diam.) that were located in the centrosomal region of the cell. Endocytosed WGA-HMWAG complexes did not become associated with cisternae of the Golgi apparatus, although tubular and vesicular endosomes were noted in the vicinity of the trans-Golgi region. The accumulation of WGA-HMWAG in the endosomes within the centrosomal region was inhibited when cells were incubated at 18 degrees C. None of these compartments contained acid phosphatase activity, a result that is consistent with other data that the HMWAG do not pass through lysosomes initially. The kinetics of labeling were consistent with the interpretation that recycling of most of the WGA binding surface glycoproteins occurred rapidly from early peripheral endosomes followed by the

Experimental analysis of performance degradation of micro-tubular solid oxide fuel cells fed by different fuel mixtures

Science.gov (United States)

Calise, F.; Restucccia, G.; Sammes, N.

This paper analyzes the thermodynamic and electrochemical dynamic performance of an anode supported micro-tubular solid oxide fuel cell (SOFC) fed by different types of fuel. The micro-tubular SOFC used is anode supported, consisting of a NiO and Gd 0.2Ce 0.8O 2- x (GDC) cermet anode, thin GDC electrolyte, and a La 0.6Sr 0.4Co 0.2Fe 0.8O 3- y (LSCF) and GDC cermet cathode. The fabrication of the cells under investigation is briefly summarized, with emphasis on the innovations with respect to traditional techniques. Such micro-tubular cells were tested using a Test Stand consisting of: a vertical tubular furnace, an electrical load, a galvanostast, a bubbler, gas pipelines, temperature, pressure and flow meters. The tests on the micro-SOFC were performed using H 2, CO, CH 4 and H 2O in different combinations at 550 °C, to determine the cell polarization curves under several load cycles. Long-term experimental tests were also performed in order to assess degradation of the electrochemical performance of the cell. Results of the tests were analyzed aiming at determining the sources of the cell performance degradation. Authors concluded that the cell under investigation is particularly sensitive to the carbon deposition which significantly reduces cell performance, after few cycles, when fed by light hydrocarbons. A significant performance degradation is also detected when hydrogen is used as fuel. In this case, the authors ascribe the degradation to the micro-cracks, the change in materials crystalline structure and problems with electrical connections.

Dragon (repulsive guidance molecule RGMb) inhibits E-cadherin expression and induces apoptosis in renal tubular epithelial cells.

Science.gov (United States)

Liu, Wenjing; Li, Xiaoling; Zhao, Yueshui; Meng, Xiao-Ming; Wan, Chao; Yang, Baoxue; Lan, Hui-Yao; Lin, Herbert Y; Xia, Yin

2013-11-01

Dragon is one of the three members of the repulsive guidance molecule (RGM) family, i.e. RGMa, RGMb (Dragon), and RGMc (hemojuvelin). We previously identified the RGM members as bone morphogenetic protein (BMP) co-receptors that enhance BMP signaling. Our previous studies found that Dragon is highly expressed in the tubular epithelial cells of mouse kidneys. However, the roles of Dragon in renal epithelial cells are yet to be defined. We now show that overexpression of Dragon increased cell death induced by hypoxia in association with increased cleaved poly(ADP-ribose) polymerase and cleaved caspase-3 levels in mouse inner medullary collecting duct (IMCD3) cells. Dragon also inhibited E-cadherin expression but did not affect epithelial-to-mesenchymal transition induced by TGF-β in IMCD3 cells. Previous studies suggest that the three RGM members can function as ligands for the receptor neogenin. Interestingly, our present study demonstrates that the Dragon actions on apoptosis and E-cadherin expression in IMCD3 cells were mediated by the neogenin receptor but not through the BMP pathway. Dragon expression in the kidney was up-regulated by unilateral ureteral obstruction in mice. Compared with wild-type mice, heterozygous Dragon knock-out mice exhibited 45-66% reduction in Dragon mRNA expression, decreased epithelial apoptosis, and increased tubular E-cadherin expression and had attenuated tubular injury after unilateral ureteral obstruction. Our results suggest that Dragon may impair tubular epithelial integrity and induce epithelial apoptosis both in vitro and in vivo.

Performance of a vanadium redox flow battery with tubular cell design

Science.gov (United States)

Ressel, Simon; Laube, Armin; Fischer, Simon; Chica, Antonio; Flower, Thomas; Struckmann, Thorsten

2017-07-01

We present a vanadium redox flow battery with a tubular cell design which shall lead to a reduction of cell manufacturing costs and the realization of cell stacks with reduced shunt current losses. Charge/discharge cycling and polarization curve measurements are performed to characterize the single test cell performance. A maximum current density of 70 mAcm-2 and power density of 142 Wl-1 (per cell volume) is achieved and Ohmic overpotential is identified as the dominant portion of the total cell overpotential. Cycling displays Coulomb efficiencies of ≈95% and energy efficiencies of ≈55%. During 113 h of operation a stable Ohmic cell resistance is observed.

Fabrication and characterization of a cathode-supported tubular solid oxide fuel cell

Energy Technology Data Exchange (ETDEWEB)

Zhao, Chunhua; Liu, Renzhu; Wang, Shaorong; Wang, Zhenrong; Qian, Jiqin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2009-07-15

A cathode-supported tubular solid oxide fuel cell (CTSOFC) with the length of 6.0 cm and outside diameter of 1.0 cm has been successfully fabricated via dip-coating and co-sintering techniques. A crack-free electrolyte film with a thickness of {proportional_to}14 {mu}m was obtained by co-firing of cathode/cathode active layer/electrolyte/anode at 1250 C. The relative low densifying temperature for electrolyte was attributed to the large shrinkage of the green tubular which assisted the densification of electrolyte. The assembled cell was electrochemically characterized with humidified H{sub 2} as fuel and O{sub 2} as oxidant. The open circuit voltages (OCV) were 1.1, 1.08 and 1.06 V at 750, 800 and 850 C, respectively, with the maximum power densities of 157, 272 and 358 mW cm{sup -2} at corresponding temperatures. (author)

Effect of benazepril on the transdifferentiation of renal tubular epithelial cells from diabetic rats.

Science.gov (United States)

Peng, Tao; Wang, Jie; Zhen, Junhui; Hu, Zhao; Yang, Xiangdong

2014-07-01

The aim of this study was to investigate the effect of benazepril on the transdifferentiation of renal tubular epithelial cells from diabetic rats. Thirty male Sprague-Dawley rats were included in the present study. Eight of the 30 rats were randomly selected and served as the normal control group (N group), while the remaining 22 rats, injected with streptozotocin (STZ), comprised the diabetic rat model. Rats with diabetes were randomly divided into the diabetic (DM group) and benazepril (B group) groups. The total course was conducted over 12 weeks. Blood glucose, body weight, kidney/body weight, 24-h urinary protein, serum creatinine and blood urea nitrogen were measured at the start and end of the study. We observed the tubulointerstitial pathological changes, and applied immunohistochemistry and western blotting to detect the expression of α-smooth muscle actin (α-SMA) in renal tissue. The levels of blood glucose, kidney/body weight, 24-h urinary protein, serum creatinine, blood urea nitrogen and tubulointerstitial damage index (TII) in the DM group were significantly higher than that in the N group (pbenazepril significantly reduced the expression of α-SMA in renal tubular epithelial cells obtained from diabetic rats, inhibited the transdifferentiation of renal tubular epithelial cells and played an important role in kidney protection.

Dragon (Repulsive Guidance Molecule RGMb) Inhibits E-cadherin Expression and Induces Apoptosis in Renal Tubular Epithelial Cells*

Science.gov (United States)

Liu, Wenjing; Li, Xiaoling; Zhao, Yueshui; Meng, Xiao-Ming; Wan, Chao; Yang, Baoxue; Lan, Hui-Yao; Lin, Herbert Y.; Xia, Yin

2013-01-01

Dragon is one of the three members of the repulsive guidance molecule (RGM) family, i.e. RGMa, RGMb (Dragon), and RGMc (hemojuvelin). We previously identified the RGM members as bone morphogenetic protein (BMP) co-receptors that enhance BMP signaling. Our previous studies found that Dragon is highly expressed in the tubular epithelial cells of mouse kidneys. However, the roles of Dragon in renal epithelial cells are yet to be defined. We now show that overexpression of Dragon increased cell death induced by hypoxia in association with increased cleaved poly(ADP-ribose) polymerase and cleaved caspase-3 levels in mouse inner medullary collecting duct (IMCD3) cells. Dragon also inhibited E-cadherin expression but did not affect epithelial-to-mesenchymal transition induced by TGF-β in IMCD3 cells. Previous studies suggest that the three RGM members can function as ligands for the receptor neogenin. Interestingly, our present study demonstrates that the Dragon actions on apoptosis and E-cadherin expression in IMCD3 cells were mediated by the neogenin receptor but not through the BMP pathway. Dragon expression in the kidney was up-regulated by unilateral ureteral obstruction in mice. Compared with wild-type mice, heterozygous Dragon knock-out mice exhibited 45–66% reduction in Dragon mRNA expression, decreased epithelial apoptosis, and increased tubular E-cadherin expression and had attenuated tubular injury after unilateral ureteral obstruction. Our results suggest that Dragon may impair tubular epithelial integrity and induce epithelial apoptosis both in vitro and in vivo. PMID:24052264

Mucinous tubular and spindle cell carcinoma of kidney: A rare case report and review of the literature

Directory of Open Access Journals (Sweden)

Geramizadeh Bita

2009-10-01

Full Text Available Low grade mucinous tubular and spindle cell carcinoma of kidney was newly established as a distinct renal cell carcinoma in the World Health Organization (WHO classification of 2004. Until now, less than 60 cases have been reported and the largest series represented approximately 15 patients with this type of tumor. Herein, we report a case of mucinous tubular and spindle cell carcinoma in a 63-year-old male presented with right flank pain which was diagnosed after nephrectomy. Pathologists should consider this diagnosis and its spectrum of histopathologic features in mind to ensure an accurate diagnosis.

Bmi-1 plays a critical role in the protection from acute tubular necrosis by mobilizing renal stem/progenitor cells

International Nuclear Information System (INIS)

Lv, Xianhui; Yu, Zhenzhen; Xie, Chunfeng; Dai, Xiuliang; Li, Qing; Miao, Dengshun; Jin, Jianliang

2017-01-01

The regeneration of injured tubular cell occurs primarily from intrinsic renal stem/progenitor cells (RSCs) labeled with CD24 and CD133 after acute tubular necrosis (ATN). Bmi-1 plays a crucial role in regulating self-renewal, differentiation and aging of multiple adult stem cells and progenitor cells. Bmi-1 was rapidly elevated in the induction of adult kidney regeneration by renal injury. To determine whether Bmi-1 maintained mobilization of RSCs in the protection from ATN, glycerol-rhabdomyolysis-induced ATN were performed in wild type (WT) and Bmi-1-deficient (Bmi-1 −/− ) mice. Their ATN phenotypes were analyzed; CD24 and CD133 double positive (CD24 + CD133 + ) cells were measured; and the levels of serum urea nitrogen (SUN) and serum creatinine (SCr) were detected. We found that CD24 + CD133 + RSCs were mobilized in WT ATN mice with the increased expression of Bmi-1; Bmi-1 deficiency led to increased tubular cast formation and necrosis, elevated levels of SUN and SCr, decreased tubular proliferation, and immobilized ratio of RSCs in ATN. These findings indicated that Bmi-1 played a critical role in the protection from ATN by maintaining mobilization of RSCs and would be a novel therapeutic target for preventing the progression of ATN.

Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single kidney in the pig

International Nuclear Information System (INIS)

Robbins, Mike E. C.; Bonsib, Stephen M.; Ikeda, Andrea; Soranson, Julie A.; Wilson, George D.; Rezvani, Mohi; Golding, Stephen J.; Whitehouse, Elizabeth; Hopewell, John W.

1995-01-01

Purpose: Radiation-induced changes in glomerular and tubular cell kinetics and morphology following irradiation of a single pig kidney were assessed. Methods and Materials: The right kidney of 13 adult female Large White pigs was irradiated with a single dose of 9.8 Gy γ rays. Animals were serially killed between 2 and 24 weeks postirradiation (PI); 1 h prior to postmortem each pig received 500 mg bromodeoxyuridine (BrdUrd). At postmortem, both kidneys were removed and tissue taken to prepare cell suspensions. The labeling index (LI) of these suspensions was measured using flow cytometry; in vivo BrdUrd incorporation in glomerular and tubular cells was determined immunohistochemically. The kidneys were also assessed histologically. Results: Irradiation of the right kidney alone resulted in a significant increase in renal cell LI in both the irradiated and the contralateral unirradiated kidney within 2 weeks of irradiation; peak values of 1.57 ± 0.32% and 1.04 ± 0.13%, respectively, were seen 4 weeks PI, significantly greater p < 0.001) than the preirradiation value of 0.18 ± 0.01%. The LI values then declined with time, but remained greater than those seen prior to irradiation. A similar pattern of response was determined from counts of labeled glomerular and tubular cells identified immunohistochemically. The increase in labeled glomerular cells was seen 2 weeks PI, whereas that for the tubular cells did not occur until 4 weeks PI. The irradiated kidney exhibited diffuse, progressive glomerular alterations. In contrast, tubular damage was focal; the irradiated kidney also exhibited a prominent vasculopathy, involving arteriolar and peripheral interlobular artery thickening. The contralateral unirradiated kidney appeared unchanged. Conclusion: These findings confirm the hypothesis that the morphologic and kinetic responses observed after irradiation of a single kidney are similar to those observed after irradiation of both kidneys. Renal irradiation results in

TWEAK activates the non-canonical NFkappaB pathway in murine renal tubular cells: modulation of CCL21.

Directory of Open Access Journals (Sweden)

Ana B Sanz

2010-01-01

Full Text Available TWEAK is a member of the TNF superfamily of cytokines that contribute to kidney tubulointerstitial injury. It has previously been reported that TWEAK induces transient nuclear translocation of RelA and expression of RelA-dependent cytokines in renal tubular cells. Additionally, TWEAK induced long-lasting NFkappaB activation suggestive of engagement of the non-canonical NFkappaB pathway. We now explore TWEAK-induced activation of NFkappaB2 and RelB, as well as expression of CCL21, a T-cell chemotactic factor, in cultured murine tubular epithelial cells and in healthy kidneys in vivo. In cultured tubular cells, TWEAK and TNFalpha activated different DNA-binding NFkappaB complexes. TWEAK-induced sustained NFkappaB activation was associated with NFkappaB2 p100 processing to p52 via proteasome and nuclear translocation and DNA-binding of p52 and RelB. TWEAK, but not TNFalpha used as control, induced a delayed increase in CCL21a mRNA (3.5+/-1.22-fold over control and CCL21 protein (2.5+/-0.8-fold over control, which was prevented by inhibition of the proteasome, or siRNA targeting of NIK or RelB, but not by RelA inhibition with parthenolide. A second NFkappaB2-dependent chemokine, CCL19, was upregulates by TWEAK, but not by TNFalpha. However, both cytokines promoted chemokine RANTES expression (3-fold mRNA at 24 h. In vivo, TWEAK induced nuclear NFkappaB2 and RelB translocation and CCL21a mRNA (1.5+/-0.3-fold over control and CCL21 protein (1.6+/-0.5-fold over control expression in normal kidney. Increased tubular nuclear RelB and tubular CCL21 expression in acute kidney injury were decreased by neutralization (2+/-0.9 vs 1.3+/-0.6-fold over healthy control or deficiency of TWEAK (2+/-0.9 vs 0.8+/-0.6-fold over healthy control. Moreover, anti-TWEAK treatment prevented the recruitment of T cells to the kidney in this model (4.1+/-1.4 vs 1.8+/-1-fold over healthy control. Our results thus identify TWEAK as a regulator of non-canonical NFkappa

Distribution of IGF receptors in the plasma membrane of proximal tubular cells

International Nuclear Information System (INIS)

Hammerman, M.R.; Rogers, S.

1987-01-01

To characterize the distribution of receptors for insulin-like growth factors I and II (IGF I and II) in the plasma membrane of the renal proximal tubular cell, the authors measured binding of 125 I-labeled IGF I and 125 I-labeled IGF II to proximal tubular basolateral and brush-border membranes and characterized IGF I-stimulated phosphorylation of detergent-solubilized membranes. 125 I-IGF bound primarily to a 135,000 relative molecular weight (M r ) protein and IGF II to a 260,000 M r protein in isolated membranes. Binding of 125 I-IGF I was severalfold greater in basolateral than in brush-border membranes. IGF I-stimulated phosphorylation of the 92,000 M r β-subunit of its receptors could be demonstrated only in basolateral membranes. These findings are consistent with an asymmetrical distribution of receptors for IGF I in the plasma membrane of the renal proximal tubular cell, localization being primary on the basolateral side. In contrast, binding of 125 I-IGF II to isolated basolateral and brush-border membranes was equivalent, suggesting that receptors for this peptide are distributed more symmetrically in the plasma membrane. The findings suggest that the action of IGF I in proximal tubule are mediated via interaction of circulating peptide with specific receptors in the basolateral membrane. However, the findings established the potential for actions of IGF II to be exerted in proximal tubule via interaction with both basolateral and/or brush-border membrane receptors

Sirt1 protects against oxidative stress-induced renal tubular cell apoptosis by the bidirectional regulation of catalase expression

International Nuclear Information System (INIS)

Hasegawa, Kazuhiro; Wakino, Shu; Yoshioka, Kyoko; Tatematsu, Satoru; Hara, Yoshikazu; Minakuchi, Hitoshi; Washida, Naoki; Tokuyama, Hirobumi; Hayashi, Koichi; Itoh, Hiroshi

2008-01-01

NAD + -dependent protein deacetylase Sirt1 regulates cellular apoptosis. We examined the role of Sirt1 in renal tubular cell apoptosis by using HK-2 cells, proximal tubular cell lines with or without reactive oxygen species (ROS), H 2 O 2 . Without any ROS, Sirt1 inhibitors enhanced apoptosis and the expression of ROS scavenger, catalase, and Sirt1 overexpression downregulated catalase. When apoptosis was induced with H 2 O 2 , Sirt1 was upregulated with the concomitant increase in catalase expression. Sirt1 overexpression rescued H 2 O 2 -induced apoptosis through the upregulation of catalase. H 2 O 2 induced the nuclear accumulation of forkhead transcription factor, FoxO3a and the gene silencing of FoxO3a enhanced H 2 O 2 -induced apoptosis. In conclusion, endogenous Sirt1 maintains cell survival by regulating catalase expression and by preventing the depletion of ROS required for cell survival. In contrast, excess ROS upregulates Sirt1, which activates FoxO3a and catalase leading to rescuing apoptosis. Thus, Sirt1 constitutes a determinant of renal tubular cell apoptosis by regulating cellular ROS levels

Bmi-1 plays a critical role in the protection from acute tubular necrosis by mobilizing renal stem/progenitor cells.

Science.gov (United States)

Lv, Xianhui; Yu, Zhenzhen; Xie, Chunfeng; Dai, Xiuliang; Li, Qing; Miao, Dengshun; Jin, Jianliang

2017-01-22

The regeneration of injured tubular cell occurs primarily from intrinsic renal stem/progenitor cells (RSCs) labeled with CD24 and CD133 after acute tubular necrosis (ATN). Bmi-1 plays a crucial role in regulating self-renewal, differentiation and aging of multiple adult stem cells and progenitor cells. Bmi-1 was rapidly elevated in the induction of adult kidney regeneration by renal injury. To determine whether Bmi-1 maintained mobilization of RSCs in the protection from ATN, glycerol-rhabdomyolysis-induced ATN were performed in wild type (WT) and Bmi-1-deficient (Bmi-1 -/- ) mice. Their ATN phenotypes were analyzed; CD24 and CD133 double positive (CD24 + CD133 + ) cells were measured; and the levels of serum urea nitrogen (SUN) and serum creatinine (SCr) were detected. We found that CD24 + CD133 + RSCs were mobilized in WT ATN mice with the increased expression of Bmi-1; Bmi-1 deficiency led to increased tubular cast formation and necrosis, elevated levels of SUN and SCr, decreased tubular proliferation, and immobilized ratio of RSCs in ATN. These findings indicated that Bmi-1 played a critical role in the protection from ATN by maintaining mobilization of RSCs and would be a novel therapeutic target for preventing the progression of ATN. Copyright © 2016 Elsevier Inc. All rights reserved.

Regulatory mechanism of ulinastatin on autophagy of macrophages and renal tubular epithelial cells

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Wu Ming

2018-04-01

Full Text Available Kidney ischemia and hypoxia can cause renal cell apoptosis and activation of inflammatory cells, which lead to the release of inflammatory factors and ultimately result in the damage of kidney tissue and the whole body. Renal tubular cell and macrophage autophagy can reduce the production of reactive oxygen species (ROS, thereby reducing the activation of inflammatory cytoplasm and its key effector protein, caspase-1, which reduces the expression of IL-1β and IL-18 and other inflammatory factors. Ulinastatin (UTI, as a glycoprotein drug, inhibits the activity of multiple proteases and reduces myocardial damage caused by ischemia-reperfusion by upregulating autophagy. However, it can be raised by macrophage autophagy, reduce the production of ROS, and ultimately reduce the expression of inflammatory mediators, thereby reducing renal cell injury, promote renal function recovery is not clear. In this study, a series of cell experiments have shown that ulinastatin is reduced by regulating the autophagy of renal tubular epithelial cells and macrophages to reduce the production of reactive oxygen species and inflammatory factors (TNF-α, IL-1β and IL-1, and then, increase the activity of the cells under the sugar oxygen deprivation model. The simultaneous use of cellular autophagy agonists Rapamycin (RAPA and ulinastatin has a synergistic effect on the production of reactive oxygen species and the expression of inflammatory factors.

Tubular Scaffold with Shape Recovery Effect for Cell Guide Applications

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Kazi M. Zakir Hossain

2015-07-01

Full Text Available Tubular scaffolds with aligned polylactic acid (PLA fibres were fabricated for cell guide applications by immersing rolled PLA fibre mats into a polyvinyl acetate (PVAc solution to bind the mats. The PVAc solution was also mixed with up to 30 wt % β-tricalcium phosphate (β-TCP content. Cross-sectional images of the scaffold materials obtained via scanning electron microscopy (SEM revealed the aligned fibre morphology along with a significant number of voids in between the bundles of fibres. The addition of β-TCP into the scaffolds played an important role in increasing the void content from 17.1% to 25.3% for the 30 wt % β-TCP loading, which was measured via micro-CT (µCT analysis. Furthermore, µCT analyses revealed the distribution of aggregated β-TCP particles in between the various PLA fibre layers of the scaffold. The compressive modulus properties of the scaffolds increased from 66 MPa to 83 MPa and the compressive strength properties decreased from 67 MPa to 41 MPa for the 30 wt % β-TCP content scaffold. The scaffolds produced were observed to change into a soft and flexible form which demonstrated shape recovery properties after immersion in phosphate buffered saline (PBS media at 37 °C for 24 h. The cytocompatibility studies (using MG-63 human osteosarcoma cell line revealed preferential cell proliferation along the longitudinal direction of the fibres as compared to the control tissue culture plastic. The manufacturing process highlighted above reveals a simple process for inducing controlled cell alignment and varying porosity features within tubular scaffolds for potential tissue engineering applications.

Cyclosporine A induces senescence in renal tubular epithelial cells

NARCIS (Netherlands)

Jennings, Paul; Koppelstaetter, Christian; Aydin, Sonia; Abberger, Thomas; Wolf, Anna Maria; Mayer, Gert; Pfaller, Walter

The nephrotoxic potential of the widely used immunosuppressive agent cyclosporine A (CsA) is well recognized. However, the mechanism of renal tubular toxicity is not yet fully elucidated. Chronic CsA nephropathy and renal organ aging share some clinical features, such as renal fibrosis and tubular

Tubular membrane bioreactors for biotechnological processes.

Science.gov (United States)

Wolff, Christoph; Beutel, Sascha; Scheper, Thomas

2013-02-01

This article is an overview of bioreactors using tubular membranes such as hollow fibers or ceramic capillaries for cultivation processes. This diverse group of bioreactor is described here in regard to the membrane materials used, operational modes, and configurations. The typical advantages of this kind of system such as environments with low shear stress together with high cell densities and also disadvantages like poor oxygen supply are summed up. As the usage of tubular membrane bioreactors is not restricted to a certain organism, a brief overview of various applications covering nearly all types of cells from prokaryotic to eukaryotic cells is also given here.

Overexpressed cyclophilin B suppresses aldosterone-induced proximal tubular cell injury both in vitro and in vivo.

Science.gov (United States)

Wang, Bin; Lin, Lilu; Wang, Haidong; Guo, Honglei; Gu, Yong; Ding, Wei

2016-10-25

The renin-angiotensin-aldosterone system (RAAS) is overactivated in patients with chronic kidney disease. Oxidative stress and endoplasmic reticulum stress (ERS) are two major mechanisms responsible for aldosterone-induced kidney injury. Cyclophilin (CYP) B is a chaperone protein that accelerates the rate of protein folding through its peptidyl-prolyl cis-trans isomerase (PPIase) activity. We report that overexpression of wild-type CYPB attenuated aldosterone-induced oxidative stress (evidenced by reduced production of reactive oxygen species and improved mitochondrial dysfunction), ERS (indicated by reduced expression of the ERS markers glucose-regulated protein 78 [GRP78] and C/-EBP homologous protein [CHOP]), and tubular cell apoptosis in comparison with aldosterone-induced human kidney-2 (HK-2) cells. The in vivo study also yielded similar results. Hence, CYPB performs a crucial function in protecting cells against aldosterone-induced oxidative stress, ERS, and tubular cell injury via its PPIase activity.

Selective ablation of the androgen receptor in mouse sertoli cells affects sertoli cell maturation, barrier formation and cytoskeletal development.

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Ariane Willems

2010-11-01

Full Text Available The observation that mice with a selective ablation of the androgen receptor (AR in Sertoli cells (SC (SCARKO mice display a complete block in meiosis supports the contention that SC play a pivotal role in the control of germ cell development by androgens. To delineate the physiological and molecular mechanism responsible for this control, we compared tubular development in pubertal SCARKO mice and littermate controls. Particular attention was paid to differences in SC maturation, SC barrier formation and cytoskeletal organization and to the molecular mediators potentially involved. Functional analysis of SC barrier development by hypertonic perfusion and lanthanum permeation techniques and immunohistochemical analysis of junction formation showed that SCARKO mice still attempt to produce a barrier separating basal and adluminal compartment but that barrier formation is delayed and defective. Defective barrier formation was accompanied by disturbances in SC nuclear maturation (immature shape, absence of prominent, tripartite nucleoli and SC polarization (aberrant positioning of SC nuclei and cytoskeletal elements such as vimentin. Quantitative RT-PCR was used to study the transcript levels of genes potentially related to the described phenomena between day 8 and 35. Differences in the expression of SC genes known to play a role in junction formation could be shown from day 8 for Cldn11, from day 15 for Cldn3 and Espn, from day 20 for Cdh2 and Jam3 and from day 35 for ZO-1. Marked differences were also noted in the transcript levels of several genes that are also related to cell adhesion and cytoskeletal dynamics but that have not yet been studied in SC (Actn3, Ank3, Anxa9, Scin, Emb, Mpzl2. It is concluded that absence of a functional AR in SC impedes the remodeling of testicular tubules expected at the onset of spermatogenesis and interferes with the creation of the specific environment needed for germ cell development.

SOFC mini-tubulares basadas en YSZ

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Campana, R.

2008-08-01

Full Text Available Tubular SOFC have the advantage over planar SOFC of the low temperature sealing and more resistance to thermal shock. On the other hand the volumetric power density of tubular Fuel Cells goes with the inverse of the tube diameter which added to the faster warm-up kinetics makes low diameter tubular SOFC favorable for low power applications. Anode supported tubular SOFC of 3mm diameter and 150 mm length with YSZ electrolyte were fabricated and tested by V-I measurements using H₂-Ar (5, 10, 100 vol% as fuel and air for the cathode. The NiO-YSZ tubes of about 400 μm thickness were produced by hydrostatic pressure and then coated with an YSZ film of 15-20 μm. The electrolyte was deposited using a manual aerograph. After sintering either Pt paste or LSF (with YSZ or SDC coatings of about 20-50 μm thickness were deposited for the cathode. The OCV of the cells were excellent, very close to the expected Nernst law prediction indicating that there were not gas leaks. The maximun electrical power of the cell was near to 500mW/cm² at 850^ºC operation temperature. Complex impedance measurements of the cells were performed in order to determine the resistance of the different cell components.

La principal ventaja de las SOFC tubulares frente a las planares es el sellado de la cámara anódica y catódica a bajas temperaturas. Además la densidad de energía volumétrica de las pilas tubulares es inversamente proporcional al diámetro del tubo, que añadido a los tiempos cortos de encendido y apagado hacen que las mini-tubulares sean interesantes para usos de baja potencia. Se han fabricado y caracterizado SOFC tubulares soportadas en ánodo de 3mm de diámetro y de 150 mm de longitud, 400μm de espesor, con electrolito de YSZ depositado por spray de 15-20 μm. Los tubos de NiO-YSZ son producidos por prensado isostático. La caracterización eléctrica se ha realizado empleando H₂-Ar como combustible an

Performance and long term degradation of 7 W micro-tubular solid oxide fuel cells for portable applications

Science.gov (United States)

Torrell, M.; Morata, A.; Kayser, P.; Kendall, M.; Kendall, K.; Tarancón, A.

2015-07-01

Micro-tubular SOFCs have shown an astonishing thermal shock resistance, many orders of magnitude larger than planar SOFCs, opening the possibility of being used in portable applications. However, only few studies have been devoted to study the degradation of large-area micro-tubular SOFCs. This work presents microstructural, electrochemical and long term degradation studies of single micro-tubular cells fabricated by high shear extrusion, operating in the intermediate range of temperatures (T∼700 °C). A maximum power of 7 W per cell has been measured in a wide range of fuel utilizations between 10% and 60% at 700 °C. A degradation rate of 360 mW/1000 h (8%) has been observed for cells operated over more than 1500 h under fuel utilizations of 40%. Higher fuel utilizations lead to strong degradations associated to nickel oxidation/reduction processes. Quick thermal cycling with heating ramp rates of 30 °C /min yielded degradation rates of 440 mW/100 cycles (9%). These reasonable values of degradation under continuous and thermal cycling operation approach the requirements for many portable applications including auxiliary power units or consumer electronics opening this typically forbidden market to the SOFC technology.

Power generation characteristics of tubular type SOFC by wet process

Energy Technology Data Exchange (ETDEWEB)

Tajiri, H.; Nakayama, T. [Kyushu Electric Power Company, Inc., Fukuoka (Japan); Kuroishi, M. [TOTO Ltd., Kanagawa (Japan)] [and others

1996-12-31

The development of a practical solid oxide fuel cell requires improvement of a cell performance and a cell manufacturing technology suitable for the mass production. In particular tubular type SOFC is thought to be superior in its reliability because its configuration can avoid the high temperature sealing and reduce the thermal stress resulting from the contact between cells. The authors have fabricated a tubular cell with an air electrode support by a wet processing technique, which is suitable for mass production in improving a power density. To enhance the power output of the module, the Integrated Tubular-Type (ITT) cell has been developed. This paper reports the performance of the single cells with various active anode areas and the bundle with series-connected 9-ITT cells with an active anode area of 840 cm{sup 2}.

Lovastatin prevents cisplatin-induced activation of pro-apoptotic DNA damage response (DDR) of renal tubular epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Krüger, Katharina; Ziegler, Verena; Hartmann, Christina; Henninger, Christian [Institute of Toxicology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf (Germany); Thomale, Jürgen [Institute of Cell Biology, University Duisburg-Essen, 45122 Essen (Germany); Schupp, Nicole [Institute of Toxicology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf (Germany); Fritz, Gerhard, E-mail: fritz@uni-duesseldorf.de [Institute of Toxicology, Medical Faculty, Heinrich Heine University Düsseldorf, 40225 Düsseldorf (Germany)

2016-02-01

The platinating agent cisplatin (CisPt) is commonly used in the therapy of various types of solid tumors. The anticancer efficacy of CisPt largely depends on the formation of bivalent DNA intrastrand crosslinks, which stimulate mechanisms of the DNA damage response (DDR), thereby triggering checkpoint activation, gene expression and cell death. The clinically most relevant adverse effect associated with CisPt treatment is nephrotoxicity that results from damage to renal tubular epithelial cells. Here, we addressed the question whether the HMG-CoA-reductase inhibitor lovastatin affects the DDR of renal cells by employing rat renal proximal tubular epithelial (NRK-52E) cells as in vitro model. The data show that lovastatin has extensive inhibitory effects on CisPt-stimulated DDR of NRK-52E cells as reflected on the levels of phosphorylated ATM, Chk1, Chk2, p53 and Kap1. Mitigation of CisPt-induced DDR by lovastatin was independent of the formation of DNA damage as demonstrated by (i) the analysis of Pt-(GpG) intrastrand crosslink formation by Southwestern blot analyses and (ii) the generation of DNA strand breaks as analyzed on the level of nuclear γH2AX foci and employing the alkaline comet assay. Lovastatin protected NRK-52E cells from the cytotoxicity of high CisPt doses as shown by measuring cell viability, cellular impedance and flow cytometry-based analyses of cell death. Importantly, the statin also reduced the level of kidney DNA damage and apoptosis triggered by CisPt treatment of mice. The data show that the lipid-lowering drug lovastatin extensively counteracts pro-apoptotic signal mechanisms of the DDR of tubular epithelial cells following CisPt injury. - Highlights: • Lovastatin blocks ATM/ATR-regulated DDR of tubular cells following CisPt treatment. • Lovastatin attenuates CisPt-induced activation of protein kinase ATM in vitro. • Statin-mediated DDR inhibition is independent of initial DNA damage formation. • Statin-mediated blockage of Cis

Lovastatin prevents cisplatin-induced activation of pro-apoptotic DNA damage response (DDR) of renal tubular epithelial cells

International Nuclear Information System (INIS)

Krüger, Katharina; Ziegler, Verena; Hartmann, Christina; Henninger, Christian; Thomale, Jürgen; Schupp, Nicole; Fritz, Gerhard

2016-01-01

The platinating agent cisplatin (CisPt) is commonly used in the therapy of various types of solid tumors. The anticancer efficacy of CisPt largely depends on the formation of bivalent DNA intrastrand crosslinks, which stimulate mechanisms of the DNA damage response (DDR), thereby triggering checkpoint activation, gene expression and cell death. The clinically most relevant adverse effect associated with CisPt treatment is nephrotoxicity that results from damage to renal tubular epithelial cells. Here, we addressed the question whether the HMG-CoA-reductase inhibitor lovastatin affects the DDR of renal cells by employing rat renal proximal tubular epithelial (NRK-52E) cells as in vitro model. The data show that lovastatin has extensive inhibitory effects on CisPt-stimulated DDR of NRK-52E cells as reflected on the levels of phosphorylated ATM, Chk1, Chk2, p53 and Kap1. Mitigation of CisPt-induced DDR by lovastatin was independent of the formation of DNA damage as demonstrated by (i) the analysis of Pt-(GpG) intrastrand crosslink formation by Southwestern blot analyses and (ii) the generation of DNA strand breaks as analyzed on the level of nuclear γH2AX foci and employing the alkaline comet assay. Lovastatin protected NRK-52E cells from the cytotoxicity of high CisPt doses as shown by measuring cell viability, cellular impedance and flow cytometry-based analyses of cell death. Importantly, the statin also reduced the level of kidney DNA damage and apoptosis triggered by CisPt treatment of mice. The data show that the lipid-lowering drug lovastatin extensively counteracts pro-apoptotic signal mechanisms of the DDR of tubular epithelial cells following CisPt injury. - Highlights: • Lovastatin blocks ATM/ATR-regulated DDR of tubular cells following CisPt treatment. • Lovastatin attenuates CisPt-induced activation of protein kinase ATM in vitro. • Statin-mediated DDR inhibition is independent of initial DNA damage formation. • Statin-mediated blockage of Cis

The entire miR-200 seed family is strongly deregulated in clear cell renal cell cancer compared to the proximal tubular epithelial cells of the kidney

NARCIS (Netherlands)

Duns, Gerben; van den Berg, Anke; van Dijk, Marcory C. R. F.; van Duivenbode, Inge; Giezen, Cor; Kluiver, Joost; van Goor, Harry; Hofstra, Robert M. W.; van den Berg, Eva; Kok, Klaas

Despite numerous studies reporting deregulated microRNA (miRNA) and gene expression patterns in clear cell renal cell carcinoma (ccRCC), no direct comparisons have been made to its presumed normal counterpart: the renal proximal tubular epithelial cells (PTECs). The aim of this study was to

Hemodynamic and tubular changes induced by contrast media.

Science.gov (United States)

Caiazza, Antonella; Russo, Luigi; Sabbatini, Massimo; Russo, Domenico

2014-01-01

The incidence of acute kidney injury induced by contrast media (CI-AKI) is the third cause of AKI in hospitalized patients. Contrast media cause relevant alterations both in renal hemodynamics and in renal tubular cell function that lead to CI-AKI. The vasoconstriction of intrarenal vasculature is the main hemodynamic change induced by contrast media; the vasoconstriction is accompanied by a cascade of events leading to ischemia and reduction of glomerular filtration rate. Cytotoxicity of contrast media causes apoptosis of tubular cells with consequent formation of casts and worsening of ischemia. There is an interplay between the negative effects of contrast media on renal hemodynamics and on tubular cell function that leads to activation of renin-angiotensin system and increased production of reactive oxygen species (ROS) within the kidney. Production of ROS intensifies cellular hypoxia through endothelial dysfunction and alteration of mechanisms regulating tubular cells transport. The physiochemical characteristics of contrast media play a critical role in the incidence of CI-AKI. Guidelines suggest the use of either isoosmolar or low-osmolar contrast media rather than high-osmolar contrast media particularly in patients at increased risk of CI-AKI. Older age, presence of atherosclerosis, congestive heart failure, chronic renal disease, nephrotoxic drugs, and diuretics may multiply the risk of CI-AKI.

Diffraction patterns from 7-Angstroms tubular halloysite

International Nuclear Information System (INIS)

Eggleton, T.

1998-01-01

Full text: The diffraction patterns from 7-Angstroms tubular halloysite are superficially like those from kaolinite. Diffraction from a tubular aggregate of atoms, however, differs from that from a crystal because there is no linear repetition in two of the three conventional crystallographic directions. In tubular halloysite, the tube axis is [010] or [110] and in this direction the unit cell repeats in the normal linear fashion. The x-axis, by contrast, changes direction tangentially around the tube circumference, and there can be no true z-axis, because unit cells in the radial direction do not superimpose, since each successive tubular layer has a larger radius than its predecessor and therefore must contain more unit cells than its predecessor. Because tubular 'crystals' do not have a lattice repeat, use of Bragg 'hkl' indices is not appropriate. In the xy plane, a small area of the structure approximates a flat layer silicate, and hk indices may been used to label diffraction maxima. Similarly, successive 1:1 layers tangential to the tube walls yield a series of apparent 001 diffraction maxima. Measurement of these shows that the d-spacings do not form an exact integral series. The reason for this lies in the curvature of the structure. Calculated electron and powder X-ray diffraction patterns, based on a model of concentric 1:1 layers with no regular relation between them other than the 7.2 Angstroms spacing, closely simulate the observed data. Evidence for the 2-layer structure that is generally accepted may need to be reassessed in the light of these results

Experimental investigations and modeling of direct internal reforming of biogases in tubular solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Lanzini, A.; Leone, P.; Pieroni, M.; Santarelli, M. [Dipartimento di Energetica, Politecnico di Torino, Corso Duca degli Abruzzi 24, IT-10129, Torino (Italy); Beretta, D.; Ginocchio, S. [Centro Ricerca e Sviluppo, Edison S.p.a, Via La Pira 2, IT-10028 Trofarello, Torino (Italy)

2011-10-15

Biogas-fed Solid Oxide Fuel Cell (SOFC) systems can be considered as interesting integrated systems in the framework of distributed power generation. In particular, bio-methane and bio-hydrogen produced from anaerobic digestion of organic wastes represent renewable carbon-neutral fuels for high efficiency electrochemical generators. With such non-conventional mixtures fed to the anode of the SOFC, the interest lies in understanding the multi-physics phenomena there occurring and optimizing the geometric and operation parameters of the SOFC, while avoiding operating and fuel conditions that can lead to or accelerate degradation processes. In this study, an anode-supported (Ni-YSZ) tubular SOFC was considered; the tubular geometry enables a relatively easy separation of the air and fuel reactants and it allows one to evaluate the temperature field of the fuel gas inside the tube, which is strictly related to the electrochemical and heterogeneous chemical reactions occurring within the anode volume. The experiments have been designed to analyze the behavior of the cell under different load and fuel utilization (FU) conditions, providing efficiency maps for both fuels. The experimental results were used to validate a multi-physics model of the tubular cell. The model showed to be in good agreement with the experimental data, and was used to study the sensitive of some selected geometrical parameters modification over the cell performances. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Endo-lysosomal dysfunction in human proximal tubular epithelial cells deficient for lysosomal cystine transporter cystinosin.

Directory of Open Access Journals (Sweden)

Ekaterina A Ivanova

Full Text Available Nephropathic cystinosis is a lysosomal storage disorder caused by mutations in the CTNS gene encoding cystine transporter cystinosin that results in accumulation of amino acid cystine in the lysosomes throughout the body and especially affects kidneys. Early manifestations of the disease include renal Fanconi syndrome, a generalized proximal tubular dysfunction. Current therapy of cystinosis is based on cystine-lowering drug cysteamine that postpones the disease progression but offers no cure for the Fanconi syndrome. We studied the mechanisms of impaired reabsorption in human proximal tubular epithelial cells (PTEC deficient for cystinosin and investigated the endo-lysosomal compartments of cystinosin-deficient PTEC by means of light and electron microscopy. We demonstrate that cystinosin-deficient cells had abnormal shape and distribution of the endo-lysosomal compartments and impaired endocytosis, with decreased surface expression of multiligand receptors and delayed lysosomal cargo processing. Treatment with cysteamine improved surface expression and lysosomal cargo processing but did not lead to a complete restoration and had no effect on the abnormal morphology of endo-lysosomal compartments. The obtained results improve our understanding of the mechanism of proximal tubular dysfunction in cystinosis and indicate that impaired protein reabsorption can, at least partially, be explained by abnormal trafficking of endosomal vesicles.

HIGH-TEMPERATURE TUBULAR SOLID OXIDE FUEL CELL GENERATOR DEVELOPMENT

Energy Technology Data Exchange (ETDEWEB)

S.E. Veyo

1998-09-01

During the Westinghouse/USDOE Cooperative Agreement period of November 1, 1990 through November 30, 1997, the Westinghouse solid oxide fuel cell has evolved from a 16 mm diameter, 50 cm length cell with a peak power of 1.27 watts/cm to the 22 mm diameter, 150 cm length dimensions of today's commercial prototype cell with a peak power of 1.40 watts/cm. Accompanying the increase in size and power density was the elimination of an expensive EVD step in the manufacturing process. Demonstrated performance of Westinghouse's tubular SOFC includes a lifetime cell test which ran for a period in excess of 69,000 hours, and a fully integrated 25 kWe-class system field test which operated for over 13,000 hours at 90% availability with less than 2% performance degradation over the entire period. Concluding the agreement period, a 100 kW SOFC system successfully passed its factory acceptance test in October 1997 and was delivered in November to its demonstration site in Westervoort, The Netherlands.

A CFD analysis of transport phenomena and electrochemical reactions in a tubular-shaped PEM fuel cell

Energy Technology Data Exchange (ETDEWEB)

Sadiq Al-Baghdadi, Maher A.R. [Fuel Cell Research Center, International Energy and Environment Foundation, Al-Najaf, P.O.Box 39 (Iraq)

2013-07-01

A fuel cell is most interesting new power source because it solves not only the environment problem but also natural resource exhaustion problem. CFD modeling and simulation for heat and mass transport in PEM fuel cells are being used extensively in researches and industrial applications to gain better understanding of the fundamental processes and to optimize fuel cell designs before building a prototype for engineering application. In this research, full three-dimensional, non-isothermal computational fluid dynamics model of a tubular-shaped proton exchange membrane (PEM) fuel cell has been developed. This comprehensive model accounts for the major transport phenomena such as convective and diffusive heat and mass transfer, electrode kinetics, transport and phase-change mechanism of water, and potential fields in a tubular-shaped PEM fuel cell. The model explains many interacting, complex electrochemical, and transport phenomena that cannot be studied experimentally. Three-dimensional results of the species profiles, temperature distribution, potential distribution, and local current density distribution are presented and analysed, with the focus on the physical insight and fundamental understanding.

A quantitative model of the cardiac ventricular cell incorporating the transverse-axial tubular system

Czech Academy of Sciences Publication Activity Database

Pásek, Michal; Christé, G.; Šimurda, J.

2003-01-01

Roč. 22, č. 3 (2003), s. 355-368 ISSN 0231-5882 R&D Projects: GA ČR GP204/02/D129 Institutional research plan: CEZ:AV0Z2076919 Keywords : cardiac cell * tubular system * quantitative modelling Subject RIV: BO - Biophysics Impact factor: 0.794, year: 2003

Hyperglycemia induced damage to mitochondrial respiration in renal mesangial and tubular cells: Implications for diabetic nephropathy

Directory of Open Access Journals (Sweden)

Anna Czajka

2016-12-01

Full Text Available Damage to renal tubular and mesangial cells is central to the development of diabetic nephropathy (DN, a complication of diabetes which can lead to renal failure. Mitochondria are the site of cellular respiration and produce energy in the form of ATP via oxidative phosphorylation, and mitochondrial dysfunction has been implicated in DN. Since the kidney is an organ with high bioenergetic needs, we postulated that hyperglycemia causes damage to renal mitochondria resulting in bioenergetic deficit. The bioenergetic profiles and the effect of hyperglycemia on cellular respiration of human primary mesangial (HMCs and proximal tubular cells (HK-2 were compared in normoglycemic and hyperglycemic conditions using the seahorse bio-analyzer. In normoglycemia, HK-2 had significantly lower basal, ATP-linked and maximal respiration rates, and lower reserve capacity compared to HMCs. Hyperglycemia caused a down-regulation of all respiratory parameters within 4 days in HK-2 but not in HMCs. After 8 days of hyperglycemia, down-regulation of respiratory parameters persisted in tubular cells with compensatory up-regulated glycolysis. HMCs had reduced maximal respiration and reserve capacity at 8 days, and by 12 days had compromised mitochondrial respiration despite which they did not enhance glycolysis. These data suggest that diabetes is likely to lead to a cellular deficit in ATP production in both cell types, although with different sensitivities, and this mechanism could significantly contribute to the cellular damage seen in the diabetic kidney. Prevention of diabetes induced damage to renal mitochondrial respiration may be a novel therapeutic approach for the prevention/treatment of DN.

Live Cell Imaging During Germination Reveals Dynamic Tubular Structures Derived from Protein Storage Vacuoles of Barley Aleurone Cells

Directory of Open Access Journals (Sweden)

Verena Ibl

2014-09-01

Full Text Available The germination of cereal seeds is a rapid developmental process in which the endomembrane system undergoes a series of dynamic morphological changes to mobilize storage compounds. The changing ultrastructure of protein storage vacuoles (PSVs in the cells of the aleurone layer has been investigated in the past, but generally this involved inferences drawn from static pictures representing different developmental stages. We used live cell imaging in transgenic barley plants expressing a TIP3-GFP fusion protein as a fluorescent PSV marker to follow in real time the spatially and temporally regulated remodeling and reshaping of PSVs during germination. During late-stage germination, we observed thin, tubular structures extending from PSVs in an actin-dependent manner. No extensions were detected following the disruption of actin microfilaments, while microtubules did not appear to be involved in the process. The previously-undetected tubular PSV structures were characterized by complex movements, fusion events and a dynamic morphology. Their function during germination remains unknown, but might be related to the transport of solutes and metabolites.

Barrier cell sheath formation

International Nuclear Information System (INIS)

Kesner, J.

1980-04-01

The solution for electrostatic potential within a simply modeled tandem mirror thermal barrier is seen to exhibit a sheath at each edge of the cell. The formation of the sheath requires ion collisionality and the analysis assmes that the collisional trapping rate into the barrier is considerably slower than the barrier pump rate

Albumin-bound fatty acids but not albumin itself alter redox balance in tubular epithelial cells and induce a peroxide-mediated redox-sensitive apoptosis

Science.gov (United States)

Ruggiero, Christine; Elks, Carrie M.; Kruger, Claudia; Cleland, Ellen; Addison, Kaity; Noland, Robert C.

2014-01-01

Albuminuria is associated with metabolic syndrome and diabetes. It correlates with the progression of chronic kidney disease, particularly with tubular atrophy. The fatty acid load on albumin significantly increases in obesity, presenting a proinflammatory environment to the proximal tubules. However, little is known about changes in the redox milieu during fatty acid overload and how redox-sensitive mechanisms mediate cell death. Here, we show that albumin with fatty acid impurities or conjugated with palmitate but not albumin itself compromised mitochondrial and cell viability, membrane potential and respiration. Fatty acid overload led to a redox imbalance which deactivated the antioxidant protein peroxiredoxin 2 and caused a peroxide-mediated apoptosis through the redox-sensitive pJNK/caspase-3 pathway. Transfection of tubular cells with peroxiredoxin 2 was protective and mitigated apoptosis. Mitochondrial fatty acid entry and ceramide synthesis modulators suggested that mitochondrial β oxidation but not ceramide synthesis may modulate lipotoxic effects on tubular cell survival. These results suggest that albumin overloaded with fatty acids but not albumin itself changes the redox environment in the tubules, inducing a peroxide-mediated redox-sensitive apoptosis. Thus, mitigating circulating fatty acid levels may be an important factor in both preserving redox balance and preventing tubular cell damage in proteinuric diseases. PMID:24500687

Berberine activates Nrf2 nuclear translocation and inhibits apoptosis induced by high glucose in renal tubular epithelial cells through a phosphatidylinositol 3-kinase/Akt-dependent mechanism.

Science.gov (United States)

Zhang, Xiuli; Liang, Dan; Lian, Xu; Jiang, Yan; He, Hui; Liang, Wei; Zhao, Yue; Chi, Zhi-Hong

2016-06-01

Apoptosis of tubular epithelial cells is a major feature of diabetic kidney disease, and hyperglycemia triggers the generation of free radicals and oxidant stress in tubular cells. Berberine (BBR) is identified as a potential anti-diabetic herbal medicine due to its beneficial effects on insulin sensitivity, glucose metabolism and glycolysis. In this study, the underlying mechanisms involved in the protective effects of BBR on high glucose-induced apoptosis were explored using cultured renal tubular epithelial cells (NRK-52E cells) and human kidney proximal tubular cell line (HK-2 cells). We identified the pivotal role of phosphatidylinositol 3-kinase (PI3K)/Akt in BBR cellular defense mechanisms and revealed the novel effect of BBR on nuclear factor (erythroid-derived 2)-related factor-2 (Nrf2) and heme oxygenase (HO)-1 in NRK-52E and HK-2 cells. BBR attenuated reactive oxygen species production, antioxidant defense (GSH and SOD) and oxidant-sensitive proteins (Nrf2 and HO-1), which also were blocked by LY294002 (an inhibitor of PI3K) in HG-treated NRK-52E and HK-2 cells. Furthermore, BBR improved mitochondrial function by increasing mitochondrial membrane potential. BBR-induced anti-apoptotic function was demonstrated by decreasing apoptotic proteins (cytochrome c, Bax, caspase3 and caspase9). All these findings suggest that BBR exerts the anti-apoptosis effects through activation of PI3K/Akt signal pathways and leads to activation of Nrf2 and induction of Nrf2 target genes, and consequently protecting the renal tubular epithelial cells from HG-induced apoptosis.

Tubular combustion

CERN Document Server

Ishizuka, Satoru

2014-01-01

Tubular combustors are cylindrical tubes where flame ignition and propagation occur in a spatially confined, highly controlled environment, in a nearly flat, elongated geometry. This allows for some unique advantages where extremely even heat dispersion is required over a large surface while still maintaining fuel efficiency. Tubular combustors also allow for easy flexibility in type of fuel source, allowing for quick changeover to meet various needs and changing fuel pricing. This new addition to the MP sustainable energy series will provide the most up-to-date research on tubular combustion--some of it only now coming out of private proprietary protection. Plentiful examples of current applications along with a good explanation of background theory will offer readers an invaluable guide on this promising energy technology. Highlights include: * An introduction to the theory of tubular flames * The "how to" of maintaining stability of tubular flames through continuous combustion * Examples of both small-scal...

Calcineurin inhibitors recruit protein kinases JAK2 and JNK, TLR signaling and the UPR to activate NF-κB-mediated inflammatory responses in kidney tubular cells

International Nuclear Information System (INIS)

González-Guerrero, Cristian; Ocaña-Salceda, Carlos; Berzal, Sergio; Carrasco, Susana; Fernández-Fernández, Beatriz

2013-01-01

The calcineurin inhibitors (CNIs) cyclosporine (CsA) and tacrolimus are key drugs in current immunosuppressive regimes for solid organ transplantation. However, they are nephrotoxic and promote death and profibrotic responses in tubular cells. Moreover, renal inflammation is observed in CNI nephrotoxicity but the mechanisms are poorly understood. We have now studied molecular pathways leading to inflammation elicited by the CNIs in cultured and kidney tubular cells. Both CsA and tacrolimus elicited a proinflammatory response in tubular cells as evidenced by a transcriptomics approach. Transcriptomics also suggested several potential pathways leading to expression of proinflammatory genes. Validation and functional studies disclosed that in tubular cells, CNIs activated protein kinases such as the JAK2/STAT3 and TAK1/JNK/AP-1 pathways, TLR4/Myd88/IRAK signaling and the Unfolded Protein Response (UPR) to promote NF-κB activation and proinflammatory gene expression. CNIs also activated an Nrf2/HO-1-dependent compensatory response and the Nrf2 activator sulforaphane inhibited JAK2 and JNK activation and inflammation. A murine model of CsA nephrotoxicity corroborated activation of the proinflammatory pathways identified in cell cultures. Human CNIs nephrotoxicity was also associated with NF-κB, STAT3 and IRE1α activation. In conclusion, CNIs recruit several intracellular pathways leading to previously non-described proinflammatory actions in renal tubular cells. Identification of these pathways provides novel clues for therapeutic intervention to limit CNIs nephrotoxicity. - Highlights: • Molecular mechanisms modulating CNI renal inflammation were investigated. • Kinases, immune receptors and ER stress mediate the inflammatory response to CNIs. • Several intracellular pathways activate NF-κB in CNIs-treated tubular cells. • A NF-κB-dependent cytokine profile characterizes CNIs-induced inflammation. • CNI nephrotoxicity was associated to inflammatory

Tubular lysosome morphology and distribution within macrophages depend on the integrity of cytoplasmic microtubules

International Nuclear Information System (INIS)

Swanson, J.; Bushnell, A.; Silverstein, S.C.

1987-01-01

Pinocytosis of the fluorescent dye lucifer yellow labels elongated, membrane-bound tubular organelles in several cell types, including cultured human monocytes, thioglycolate-elicited mouse peritoneal macrophages, and the macrophage-like cell line J774.2. These tubular structures can be identified as lysosomes by acid phosphatase histochemistry and immunofluorescence localization of cathepsin L. The abundance of tubular lysosomes is markedly increased by treatment with phorbol 12-myristate 13-acetate. When labeled by pinocytosis of microperoxidase and examined by electron microscopic histochemistry, the tubular lysosomes have an outside diameter of ≅ 75 nm and a length of several micrometers; they radiate from the cell's centrosphere in alignment with cytoplasmic microtubules and intermediate filaments. Incubation of phorbol myristate acetate-treated macrophages at 4 0 C or in medium containing 5 μM colchicine or nocodazole at 37 0 C leads to disassembly of microtubules and fragmentation of the tubular lysosomes. Return of the cultures to 37 0 C or removal of nocodazole from the medium leads to reassembly of microtubules and the reappearance of tubular lysosomes within 10-20 min. The authors conclude that microtubules are essential for the maintenance of tubular lysosome morphology and that, in macrophages, a significant proportion of the lysosomal compartment is contained within these tubular structures

Factor H and Properdin Recognize Different Epitopes on Renal Tubular Epithelial Heparan Sulfate

NARCIS (Netherlands)

Zaferani, Azadeh; Vives, Romain R.; van der Pol, Pieter; Navis, Gerjan J.; Daha, Mohamed R.; van Kooten, Cees; Lortat-Jacob, Hugues; Seelen, Marc A.; van den Born, Jacob

2012-01-01

During proteinuria, renal tubular epithelial cells become exposed to ultrafiltrate-derived serum proteins, including complement factors. Recently, we showed that properdin binds to tubular heparan sulfates (HS). We now document that factor H also binds to tubular HS, although to a different epitope

In vitro degradation and cell attachment studies of a new electrospun polymeric tubular graft.

Science.gov (United States)

Patel, Harsh N; Thai, Kevin N; Chowdhury, Sami; Singh, Raj; Vohra, Yogesh K; Thomas, Vinoy

Electrospinning technique was utilized to engineer a small-diameter (id = 4 mm) tubular graft. The tubular graft was made from biocompatible and biodegradable polymers polycaprolactone (PCL) and poliglecaprone with 3:1 (PCL:PGC) ratio. Enzymatic degradation effect on the mechanical properties and fiber morphology in the presence of lipase enzyme were observed. Significant changes in tensile strength (1.86-1.49 MPa) and strain (245-205 %) were noticed after 1 month in vitro degradation. The fiber breakage was clearly evident through scanning electron microscopy (SEM) after 4 weeks in vitro degradation. Then, the graft was coated with a collagenous protein matrix to impart bioactivity. Human umbilical vein endothelial cells (HUVECs) and aortic artery smooth muscle cells (AoSMCs) attachment on the coated graft were observed in static condition. Further, HUVECs were seeded on the lumen surface of the grafts and exposed to laminar shear stress for 12 h to understand the cell attachment. The coated graft was aged in PBS solution (pH 7.3) at 37 °C for 1 month to understand the coating stability. Differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) suggested the erosion of the protein matrix from the coated graft under in vitro condition.

Effect of taurine on advanced glycation end products-induced hypertrophy in renal tubular epithelial cells

International Nuclear Information System (INIS)

Huang, J.-S.; Chuang, L.-Y.; Guh, J.-Y.; Yang, Y.-L.; Hsu, M.-S.

2008-01-01

Mounting evidence indicates that advanced glycation end products (AGE) play a major role in the development of diabetic nephropathy (DN). Taurine is a well documented antioxidant agent. To explore whether taurine was linked to altered AGE-mediated renal tubulointerstitial fibrosis in DN, we examined the molecular mechanisms of taurine responsible for inhibition of AGE-induced hypertrophy in renal tubular epithelial cells. We found that AGE (but not non-glycated BSA) caused inhibition of cellular mitogenesis rather than cell death by either necrosis or apoptosis. There were no changes in caspase 3 activity, bcl-2 protein expression, and mitochondrial cytochrome c release in BSA, AGE, or the antioxidant taurine treatments in these cells. AGE-induced the Raf-1/extracellular signal-regulated kinase (ERK) activation was markedly blocked by taurine. Furthermore, taurine, the Raf-1 kinase inhibitor GW5074, and the ERK kinase inhibitor PD98059 may have the ability to induce cellular proliferation and cell cycle progression from AGE-treated cells. The ability of taurine, GW5074, or PD98059 to inhibit AGE-induced hypertrophy was verified by the observation that it significantly decreased cell size, cellular hypertrophy index, and protein levels of RAGE, p27 Kip1 , collagen IV, and fibronectin. The results obtained in this study suggest that taurine may serve as the potential anti-fibrotic activity in DN through mechanism dependent of its Raf-1/ERK inactivation in AGE-induced hypertrophy in renal tubular epithelial cells

Intracellular Kinases Mediate Increased Translation and Secretion of Netrin-1 from Renal Tubular Epithelial Cells

Science.gov (United States)

Jayakumar, Calpurnia; Mohamed, Riyaz; Ranganathan, Punithavathi Vilapakkam; Ramesh, Ganesan

2011-01-01

Background Netrin-1 is a laminin-related secreted protein, is highly induced after tissue injury, and may serve as a marker of injury. However, the regulation of netrin-1 production is not unknown. Current study was carried out in mouse and mouse kidney cell line (TKPTS) to determine the signaling pathways that regulate netrin-1 production in response to injury. Methods and Principal Findings Ischemia reperfusion injury of the kidney was induced in mice by clamping renal pedicle for 30 minutes. Cellular stress was induced in mouse proximal tubular epithelial cell line by treating with pervanadate, cisplatin, lipopolysaccharide, glucose or hypoxia followed by reoxygenation. Netrin-1 expression was quantified by real time RT-PCR and protein production was quantified using an ELISA kit. Cellular stress induced a large increase in netrin-1 production without increase in transcription of netrin-1 gene. Mitogen activated protein kinase, ERK mediates the drug induced netrin-1 mRNA translation increase without altering mRNA stability. Conclusion Our results suggest that netrin-1 expression is suppressed at the translational level and MAPK activation leads to rapid translation of netrin-1 mRNA in the kidney tubular epithelial cells. PMID:22046354

Intracellular kinases mediate increased translation and secretion of netrin-1 from renal tubular epithelial cells.

Directory of Open Access Journals (Sweden)

Calpurnia Jayakumar

Full Text Available BACKGROUND: Netrin-1 is a laminin-related secreted protein, is highly induced after tissue injury, and may serve as a marker of injury. However, the regulation of netrin-1 production is not unknown. Current study was carried out in mouse and mouse kidney cell line (TKPTS to determine the signaling pathways that regulate netrin-1 production in response to injury. METHODS AND PRINCIPAL FINDINGS: Ischemia reperfusion injury of the kidney was induced in mice by clamping renal pedicle for 30 minutes. Cellular stress was induced in mouse proximal tubular epithelial cell line by treating with pervanadate, cisplatin, lipopolysaccharide, glucose or hypoxia followed by reoxygenation. Netrin-1 expression was quantified by real time RT-PCR and protein production was quantified using an ELISA kit. Cellular stress induced a large increase in netrin-1 production without increase in transcription of netrin-1 gene. Mitogen activated protein kinase, ERK mediates the drug induced netrin-1 mRNA translation increase without altering mRNA stability. CONCLUSION: Our results suggest that netrin-1 expression is suppressed at the translational level and MAPK activation leads to rapid translation of netrin-1 mRNA in the kidney tubular epithelial cells.

Micro-tubular flame-assisted fuel cells for micro-combined heat and power systems

Science.gov (United States)

Milcarek, Ryan J.; Wang, Kang; Falkenstein-Smith, Ryan L.; Ahn, Jeongmin

2016-02-01

Currently the role of fuel cells in future power generation is being examined, tested and discussed. However, implementing systems is more difficult because of sealing challenges, slow start-up and complex thermal management and fuel processing. A novel furnace system with a flame-assisted fuel cell is proposed that combines the thermal management and fuel processing systems by utilizing fuel-rich combustion. In addition, the flame-assisted fuel cell furnace is a micro-combined heat and power system, which can produce electricity for homes or businesses, providing resilience during power disruption while still providing heat. A micro-tubular solid oxide fuel cell achieves a significant performance of 430 mW cm-2 operating in a model fuel-rich exhaust stream.

Regulation of proximal tubular cell differentiation and proliferation in primary culture by matrix stiffness and ECM components.

Science.gov (United States)

Chen, Wan-Chun; Lin, Hsi-Hui; Tang, Ming-Jer

2014-09-15

To explore whether matrix stiffness affects cell differentiation, proliferation, and transforming growth factor (TGF)-β1-induced epithelial-mesenchymal transition (EMT) in primary cultures of mouse proximal tubular epithelial cells (mPTECs), we used a soft matrix made from monomeric collagen type I-coated polyacrylamide gel or matrigel (MG). Both kinds of soft matrix benefited primary mPTECs to retain tubular-like morphology with differentiation and growth arrest and to evade TGF-β1-induced EMT. However, the potent effect of MG on mPTEC differentiation was suppressed by glutaraldehyde-induced cross-linking and subsequently stiffening MG or by an increasing ratio of collagen in the soft mixed gel. Culture media supplemented with MG also helped mPTECs to retain tubular-like morphology and a differentiated phenotype on stiff culture dishes as soft MG did. We further found that the protein level and activity of ERK were scaled with the matrix stiffness. U-0126, a MEK inhibitor, abolished the stiff matrix-induced dedifferentiation and proliferation. These data suggest that the ERK signaling pathway plays a vital role in matrix stiffness-regulated cell growth and differentiation. Taken together, both compliant property and specific MG signals from the matrix are required for the regulation of epithelial differentiation and proliferation. This study provides a basic understanding of how physical and chemical cues derived from the extracellular matrix regulate the physiological function of proximal tubules and the pathological development of renal fibrosis. Copyright © 2014 the American Physiological Society.

Characterization of a novel, highly integrated tubular solid oxide fuel cell system using high-fidelity simulation tools

Science.gov (United States)

Kattke, K. J.; Braun, R. J.

2011-08-01

A novel, highly integrated tubular SOFC system intended for small-scale power is characterized through a series of sensitivity analyses and parametric studies using a previously developed high-fidelity simulation tool. The high-fidelity tubular SOFC system modeling tool is utilized to simulate system-wide performance and capture the thermofluidic coupling between system components. Stack performance prediction is based on 66 anode-supported tubular cells individually evaluated with a 1-D electrochemical cell model coupled to a 3-D computational fluid dynamics model of the cell surroundings. Radiation is the dominate stack cooling mechanism accounting for 66-92% of total heat loss at the outer surface of all cells at baseline conditions. An average temperature difference of nearly 125 °C provides a large driving force for radiation heat transfer from the stack to the cylindrical enclosure surrounding the tube bundle. Consequently, cell power and voltage disparities within the stack are largely a function of the radiation view factor from an individual tube to the surrounding stack can wall. The cells which are connected in electrical series, vary in power from 7.6 to 10.8 W (with a standard deviation, σ = 1.2 W) and cell voltage varies from 0.52 to 0.73 V (with σ = 81 mV) at the simulation baseline conditions. It is observed that high cell voltage and power outputs directly correspond to tubular cells with the smallest radiation view factor to the enclosure wall, and vice versa for tubes exhibiting low performance. Results also reveal effective control variables and operating strategies along with an improved understanding of the effect that design modifications have on system performance. By decreasing the air flowrate into the system by 10%, the stack can wall temperature increases by about 6% which increases the minimum cell voltage to 0.62 V and reduces deviations in cell power and voltage by 31%. A low baseline fuel utilization is increased by decreasing the

Characterization of a PLGA sandwiched cell/fibrin tubular construct and induction of the adipose derived stem cells into smooth muscle cells

International Nuclear Information System (INIS)

Wang Xiaohong; Maekitie, Antti A.; Paloheimo, Kaija-Stiina; Tuomi, Jukka; Paloheimo, Markku; Sui Shaochun; Zhang Qiqing

2011-01-01

A poly(DL-lactic-co-glycolic acid) (PLGA) sandwiched adipose derived stem cell (ADSC)/fibrin tubular construct, fabricated using a step-by-step mold/extraction method, was characterized in this work. The ADSCs were also induced into smooth-muscle-like cells using growth factors such as hepatocyte growth factor (HGF), platelet-derived growth factor BB (PDGF-BB), transforming growth factor β1 (TGFβ1), and basic fibroblast growth factor (b-FGF). Compared with the non-induced cells, the proliferation ability of induced cells was much smaller. The PLGA sandwiched cell/hydrogel construct was shown to be useful for controlling the cellular microenvironment and cellular behaviors such as growth, migration, proliferation and differentiation. This strategy seems promising in tissue engineering and organ manufacturing.

Characterization of a PLGA sandwiched cell/fibrin tubular construct and induction of the adipose derived stem cells into smooth muscle cells

Energy Technology Data Exchange (ETDEWEB)

Wang Xiaohong, E-mail: wangxiaohong@tsinghua.edu.cn [BIT Research Centre, School of Science and Technology, Aalto University, P.O. Box 15500, 00076 Aalto (Finland); Key Laboratory for Advanced Materials Processing Technology, Ministry of Education and Center of Organ Manufacturing, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Maekitie, Antti A.; Paloheimo, Kaija-Stiina; Tuomi, Jukka; Paloheimo, Markku [BIT Research Centre, School of Science and Technology, Aalto University, P.O. Box 15500, 00076 Aalto (Finland); Sui Shaochun [Key Laboratory for Advanced Materials Processing Technology, Ministry of Education and Center of Organ Manufacturing, Department of Mechanical Engineering, Tsinghua University, Beijing 100084 (China); Zhang Qiqing [Institute of Biomedical Engineering, Chinese Academy of Medical Science and Peking Union Medical College, Key Laboratory of Biomedical Material of Tianjin, Tianjin 300192 (China)

2011-05-10

A poly(DL-lactic-co-glycolic acid) (PLGA) sandwiched adipose derived stem cell (ADSC)/fibrin tubular construct, fabricated using a step-by-step mold/extraction method, was characterized in this work. The ADSCs were also induced into smooth-muscle-like cells using growth factors such as hepatocyte growth factor (HGF), platelet-derived growth factor BB (PDGF-BB), transforming growth factor {beta}1 (TGF{beta}1), and basic fibroblast growth factor (b-FGF). Compared with the non-induced cells, the proliferation ability of induced cells was much smaller. The PLGA sandwiched cell/hydrogel construct was shown to be useful for controlling the cellular microenvironment and cellular behaviors such as growth, migration, proliferation and differentiation. This strategy seems promising in tissue engineering and organ manufacturing.

Testing of a cathode fabricated by painting with a brush pen for anode-supported tubular solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Liu, Renzhu; Zhao, Chunhua; Li, Junliang; Wang, Shaorong; Wen, Zhaoyin; Wen, Tinglian [CAS Key Laboratory of Materials for Energy Conversion, Shanghai Institute of Ceramics, Chinese Academy of Sciences (SICCAS), 1295 Dingxi Road, Shanghai 200050 (China)

2010-01-15

We have studied the properties of a cathode fabricated by painting with a brush pen for use with anode-supported tubular solid oxide fuel cells (SOFCs). The porous cathode connects well with the electrolyte. A preliminary examination of a single tubular cell, consisting of a Ni-YSZ anode support tube, a Ni-ScSZ anode functional layer, a ScSZ electrolyte film, and a LSM-ScSZ cathode fabricated by painting with a brush pen, has been carried out, and an improved performance is obtained. The ohmic resistance of the cathode side clearly decreases, falling to a value only 37% of that of the comparable cathode made by dip-coating at 850 C. The single cell with the painted cathode generates a maximum power density of 405 mW cm{sup -2} at 850 C, when operating with humidified hydrogen. (author)

Tubular and endothelial chimerism in renal allografts using fluorescence and chromogenic in situ hybridization (FISH, CISH) technology.

Science.gov (United States)

Varga, Zsuzsanna; Gaspert, Ariana; Behnke, Silvia; von Teichman, Adriana; Fritzsche, Florian; Fehr, Thomas

2012-04-01

The role of endothelial and tubular chimerism in renal allograft adaptation and rejection varies in different studies. We addressed the correlation between different clinico-pathological settings and sex-chromosomal endothelial and/or tubular chimerism in renal allografts. We examined the presence or absence of the X and Y chromosomes by fluorescence and chromogenic in situ hybridization (FISH, CISH) methodology on paraffin embedded kidney biopsies in 16 gender mismatched renal transplants (1 to 12 years post-transplantation). Twelve patients were male, four female. Four groups were selected: (i) Vascular calcineurin inhibitor toxicity without rejection; (ii) T-cell mediated vascular rejection; (iii) antibody mediated rejection; and (iv) C4d-positivity in AB0-incompatible transplants with or without rejection. Twelve non-transplant kidney biopsies (8 female, 4 male) were used as controls. Tubular chimerism was detected more frequently (69%) than endothelial chimerism (12%) in renal transplants. One of 12 control patients had tubular and endothelial chimeric cells (8%). The Y chromosome occurred in 8/12 male recipients (67%) in tubular epithelial cells and in 5/12 male recipients (42%) in endothelial cells. Double X chromosomes were detected in 3/4 female recipients in tubular epithelium. Tubular chimerism occurred more often with endothelial chimerism and capillaritis without correlation with other parameters, such as rejection. Combined Y chromosomal tubular and lymphatic endothelial chimerism correlated with T-cell mediated vascular rejection in two out of three patients (66%). Combined Y chromosomal tubular and peritubular capillary chimerism correlated with antibody mediated C4d+ rejection in one out of two patients (50%). Tubular and/or endothelial chimerism occur frequently in gender mismatched renal allografts and, when combined, this is associated with T-cell mediated rejection. © 2012 The Authors. Pathology International © 2012 Japanese Society of

Regulation of proximal tubular epithelial cell CD44-mediated binding and internalisation of hyaluronan.

Science.gov (United States)

Jones, Stuart George; Ito, Takafumi; Phillips, Aled Owain

2003-09-01

Increased expression of the connective tissue polysaccharide hyaluronan (HA) in the renal corticointerstitium is associated with progressive renal fibrosis. Numerous studies have demonstrated involvement proximal tubular epithelial cells in the fibrotic process and in the current study we have characterised their expression of the HA receptor, CD44, and examined changes in CD44 expression and function in response to either IL-1beta or glucose. Characterisation of CD44 splice variant expression was carried out in primary cultures of human proximal tubular cells (PTC) and HK2 cells. Binding and internalisation HA was examined by addition of exogenous of fluorescein-HA (fl-HA), and expression of CD44 examined by immunoblot analysis and flow cytometry. Alteration in "functional" CD44 was determined by immunoprecipitation of CD44 following stimulation in the presence of fl-HA. PTC, both primary culture and the PTC cell line, HK2, express at least 5 CD44 splice variants, the expression of which are not altered by addition of either IL-1beta or 25mM D-glucose. Addition of either stimulus increased cell surface binding and internalisation of fl-HA and increased expression of functionally active CD44. Increased binding and internalisation of fl-HA, was blocked by anti-CD44 antibody, and by the inhibition of O-glycosylation. The data demonstrate that stimuli inducing PTC HA synthesis also regulate PTC-HA interactions. Furthermore increased HA binding and internalisation is the result of post-translational modification of CD44 by O-glycosylation, rather than by alteration in expression of CD44 at the cell surface, or by alternate use of CD44 splice variants.

Renal pathophysiologic role of cortical tubular inclusion bodies.

Science.gov (United States)

Radi, Zaher A; Stewart, Zachary S; Grzemski, Felicity A; Bobrowski, Walter F

2013-01-01

Renal tubular inclusion bodies are rarely associated with drug administration. The authors describe the finding of renal cortical tubular intranuclear and intracytoplasmic inclusion bodies associated with the oral administration of a norepinephrine/serotonin reuptake inhibitor (NSRI) test article in Sprague-Dawley (SD) rats. Rats were given an NSRI daily for 4 weeks, and kidney histopathologic, ultrastructural pathology, and immunohistochemical examinations were performed. Round eosinophilic intranuclear inclusion bodies were observed histologically in the tubular epithelial cells of the renal cortex in male and female SD rats given the NSRI compound. No evidence of degeneration or necrosis was noted in the inclusion-containing renal cells. By ultrastructural pathology, inclusion bodies consisted of finely granular, amorphous, and uniformly stained nonmembrane-bound material. By immunohistochemistry, inclusion bodies stained positive for d-amino acid oxidase (DAO) protein. In addition, similar inclusion bodies were noted in the cytoplasmic tubular epithelial compartment by ultrastructural and immunohistochemical examination.  This is the first description of these renal inclusion bodies after an NSRI test article administration in SD rats. Such drug-induced renal inclusion bodies are rat-specific, do not represent an expression of nephrotoxicity, represent altered metabolism of d-amino acids, and are not relevant to human safety risk assessment.

Review: peripheral nerve regeneration using non-tubular alginate gel crosslinked with covalent bonds.

Science.gov (United States)

Hashimoto, Tadashi; Suzuki, Yoshihisa; Suzuki, Kyoko; Nakashima, Toshihide; Tanihara, Masao; Ide, Chizuka

2005-06-01

We have developed a nerve regeneration material consisting of alginate gel crosslinked with covalent bonds. in the first part of this study, we attempted to analyze nerve regeneration through alginate gel in the early stages within 2 weeks. in the second part, we tried to regenerate cat peripheral nerve by using alginate tubular or non-tubular nerve regeneration devices, and compared their efficacies. Four days after surgery, regenerating axons grew without Schwann cell investment through the partially degraded alginate gel, being in direct contact with the alginate without a basal lamina covering. One to 2 weeks after surgery, regenerating axons were surrounded by common Schwann cells, forming small bundles, with some axons at the periphery being partly in direct contact with alginate. At the distal stump, numerous Schwann cells had migrated into the alginate 8-14 days after surgery. Remarkable restorations of the 50-mm gap in cat sciatic nerve were obtained after a long term by using tubular or non-tubular nerve regeneration material consisting mainly of alginate gel. However, there was no significant difference between both groups at electrophysiological and morphological evaluation. Although, nowadays, nerve regeneration materials being marketed mostly have a tubular structure, our results suggest that the tubular structure is not indispensable for peripheral nerve regeneration.

Nerve regeneration using tubular scaffolds from biodegradable polyurethane.

Science.gov (United States)

Hausner, T; Schmidhammer, R; Zandieh, S; Hopf, R; Schultz, A; Gogolewski, S; Hertz, H; Redl, H

2007-01-01

In severe nerve lesion, nerve defects and in brachial plexus reconstruction, autologous nerve grafting is the golden standard. Although, nerve grafting technique is the best available approach a major disadvantages exists: there is a limited source of autologous nerve grafts. This study presents data on the use of tubular scaffolds with uniaxial pore orientation from experimental biodegradable polyurethanes coated with fibrin sealant to regenerate a 8 mm resected segment of rat sciatic nerve. Tubular scaffolds: prepared by extrusion of the polymer solution in DMF into water coagulation bath. The polymer used for the preparation of tubular scaffolds was a biodegradable polyurethane based on hexamethylene diisocyanate, poly(epsilon-caprolactone) and dianhydro-D-sorbitol. EXPERIMENTAL MODEL: Eighteen Sprague Dawley rats underwent mid-thigh sciatic nerve transection and were randomly assigned to two experimental groups with immediate repair: (1) tubular scaffold, (2) 180 degrees rotated sciatic nerve segment (control). Serial functional measurements (toe spread test, placing tests) were performed weekly from 3rd to 12th week after nerve repair. On week 12, electrophysiological assessment was performed. Sciatic nerve and scaffold/nerve grafts were harvested for histomorphometric analysis. Collagenic connective tissue, Schwann cells and axons were evaluated in the proximal nerve stump, the scaffold/nerve graft and the distal nerve stump. The implants have uniaxially-oriented pore structure with a pore size in the range of 2 micorm (the pore wall) and 75 x 700 microm (elongated pores in the implant lumen). The skin of the tubular implants was nonporous. Animals which underwent repair with tubular scaffolds of biodegradable polyurethanes coated with diluted fibrin sealant had no significant functional differences compared with the nerve graft group. Control group resulted in a trend-wise better electrophysiological recovery but did not show statistically significant

Attenuation of oxidative stress and inflammation by gravinol in high glucose-exposed renal tubular epithelial cells

International Nuclear Information System (INIS)

Kim, You Jung; Kim, Young Ae; Yokozawa, Takako

2010-01-01

Gravinol, a proanthocyanidin from grape seeds, has polyphenolic properties with powerful anti-oxidative effects. Although, increasing evidence strongly suggests that polyphenolic antioxidants suppress diabetic nephropathy that is causally associated with oxidative stress and inflammation, gravinol's protective action against diabetic nephropathy has not been fully explored to date. In the current study, we investigated the protective action of gravinol against oxidative stress and inflammation using the experimental diabetic nephropathy cell model, high glucose-exposed renal tubular epithelial cells. To elucidate the underlying actions of gravinol, several oxidative and inflammatory markers were estimated. Included are measurements of lipid peroxidation, total reactive species (RS), superoxide (·O 2 ), nitric oxide (NO·), and peroxynitrite (ONOO - ), as well as nuclear factor-kappa B (NF-κB) nuclear translocation. Results indicate that gravinol had a potent inhibitory action against lipid peroxidation, total RS, ·O 2 , NO·, ONOO - , the reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio and more importantly, against NF-κB nuclear translocation. We propose that gravinol's strong protective effect against high glucose-induced renal tubular epithelial cell damage attenuates diabetic nephropathy by suppressing oxidative stress and inflammation.

Intrarenal purinergic signaling in the control of renal tubular transport

DEFF Research Database (Denmark)

Prætorius, Helle; Leipziger, Jens Georg

2010-01-01

Renal tubular epithelial cells receive hormonal input that regulates volume and electrolyte homeostasis. In addition, numerous intrarenal, local signaling agonists have appeared on the stage of renal physiology. One such system is that of intrarenal purinergic signaling. This system involves all......-reaching advances indicate that ATP is often used as a local transmitter for classical sensory transduction. This transmission apparently also applies to sensory functions in the kidney. Locally released ATP is involved in sensing of renal tubular flow or in detecting the distal tubular load of NaCl at the macula...

The role of oxidative stress in the ochratoxin A-mediated toxicity in proximal tubular cells.

Science.gov (United States)

Schaaf, G J; Nijmeijer, S M; Maas, R F M; Roestenberg, P; de Groene, E M; Fink-Gremmels, J

2002-11-20

Balkan endemic nephropathy (BEN), a disease characterized by progressive renal fibrosis in human patients, has been associated with exposure to ochratoxin A (OTA). This mycotoxin is a frequent contaminant of human and animal food products, and is toxic to all animal species tested. OTA predominantly affects the kidney and is known to accumulate in the proximal tubule (PT). The induction of oxidative stress is implicated in the toxicity of this mycotoxin. In the present study, primary rat PT cells and LLC-PK(1) cells, which express characteristics of the PT, were used to investigate the OTA-mediated oxidative stress response. OTA exposure of these cells resulted in a concentration-dependent elevation of reactive oxygen species (ROS) levels, depletion of cellular glutathione (GSH) levels and an increase in the formation of 8-oxoguanine. The OTA-induced ROS response was significantly reduced following treatment with alpha-tocopherol (TOCO). However, this chain-braking anti-oxidant did not reduce the cytotoxicity of OTA and was unable to prevent the depletion of total GSH levels in OTA-exposed cells. In contrast, pre-incubation of the cell with N-acetyl-L-cysteine (NAC) completely prevented the OTA-induced increase in ROS levels as well as the formation of 8-oxoguanine and completely protected against the cytotoxicity of OTA. In addition, NAC treatment also limited the GSH depletion in OTA-exposed PT- and LLC-PK(1) cells. From these data, we conclude that oxidative stress contributes to the tubular toxicity of OTA. Subsequently, cellular GSH levels play a pivotal role in limiting the short-term toxicity of this mycotoxin in renal tubular cells.

Differential impact of glucose levels and advanced glycation end-products on tubular cell viability and pro-inflammatory/profibrotic functions.

Science.gov (United States)

Franko, Benoit; Brault, Julie; Jouve, Thomas; Beaumel, Sylvain; Benhamou, Pierre-Yves; Zaoui, Philippe; Stasia, Marie José

2014-09-05

High glucose (HG) or synthetic advanced glycation end-products (AGE) conditions are generally used to mimic diabetes in cellular models. Both models have shown an increase of apoptosis, oxidative stress and pro-inflammatory cytokine production in tubular cells. However, the impact of the two conditions combined has rarely been studied. In addition, the impact of glucose level variation due to cellular consumption is not clearly characterized in such experiments. Therefore, the aim of this study was to compare the effect of HG and AGE separately and of both on tubular cell phenotype changes in the HK2 cell line. Moreover, glucose consumption was monitored every hour to maintain the glucose level by supplementation throughout the experiments. We thus observed a significant decrease of apoptosis and H2O2 production in the HK2 cell. HG or AGE treatment induced an increase of total and mitochondrial apoptosis as well as TGF-β release compared to control conditions; however, AGE or HG led to apoptosis preferentially involving the mitochondria pathway. No cumulative effect of HG and AGE treatment was observed on apoptosis. However, a pretreatment with RAGE antibodies partially abolished the apoptotic effect of HG and completely abolished the apoptotic effect of AGE. In conclusion, tubular cells are sensitive to the lack of glucose as well as to the HG and AGE treatments, the AGE effect being more deleterious than the HG effect. Absence of a potential synergistic effect of HG and AGE could indicate that they act through a common pathway, possibly via the activation of the RAGE receptors. Copyright © 2014 Elsevier Inc. All rights reserved.

Toxicological significance of renal Bcrp: Another potential transporter in the elimination of mercuric ions from proximal tubular cells

Energy Technology Data Exchange (ETDEWEB)

Bridges, Christy C., E-mail: bridges_cc@mercer.edu; Zalups, Rudolfs K.; Joshee, Lucy

2015-06-01

Secretion of inorganic mercury (Hg{sup 2+}) from proximal tubular cells into the tubular lumen has been shown to involve the multidrug resistance-associated protein 2 (Mrp2). Considering similarities in localization and substrate specificity between Mrp2 and the breast cancer resistance protein (Bcrp), we hypothesize that Bcrp may also play a role in the proximal tubular secretion of mercuric species. In order to test this hypothesis, the uptake of Hg{sup 2+} was examined initially using inside-out membrane vesicles containing Bcrp. The results of these studies suggest that Bcrp may be capable of transporting certain conjugates of Hg{sup 2+}. To further characterize the role of Bcrp in the handling of mercuric ions and in the induction of Hg{sup 2+}-induced nephropathy, Sprague–Dawley and Bcrp knockout (bcrp{sup −/−}) rats were exposed intravenously to a non-nephrotoxic (0.5 μmol·kg{sup −1}), a moderately nephrotoxic (1.5 μmol·kg{sup −1}) or a significantly nephrotoxic (2.0 μmol·kg{sup −1}) dose of HgCl{sub 2}. In general, the accumulation of Hg{sup 2+} was greater in organs of bcrp{sup −/−} rats than in Sprague–Dawley rats, suggesting that Bcrp may play a role in the export of Hg{sup 2+} from target cells. Within the kidney, cellular injury and necrosis was more severe in bcrp{sup −/−} rats than in controls. The pattern of necrosis, which was localized in the inner cortex and the outer stripe of the outer medulla, was significantly different from that observed in Mrp2-deficient animals. These findings suggest that Bcrp may be involved in the cellular export of select mercuric species and that its role in this export may differ from that of Mrp2. - Highlights: • Bcrp may mediate transport of mercury out of proximal tubular cells. • Hg-induced nephropathy was more severe in Bcrp knockout rats. • Bcrp and Mrp2 may differ in their ability to transport Hg.

Impedance-based cell monitoring: barrier properties and beyond

Directory of Open Access Journals (Sweden)

Benson Kathrin

2013-01-01

Full Text Available Abstract In multicellular organisms epithelial and endothelial cells form selective permeable interfaces between tissue compartments of different chemical compositions. Tight junctions which connect adjacent cells, control the passage of molecules across the barrier and, in addition, facilitate active transport processes. The cellular barriers are not static but can be deliberately modulated by exposure to specific external stimuli. In vitro models representing the essential absorption barriers of the body are nowadays available, thus allowing investigation of the parameters that control permeability as well as transport processes across those barriers. Independent of the origin of the barrier forming cells, techniques are needed to quantify their barrier integrity. One simple assay is to measure the permeability for given hydrophilic substrates possessing different molecular weights like sucrose or dextrans. However, this technique is time-consuming and labor-intensive. Moreover, radioactive or fluorescently-labeled substrates are needed to allow easy analytical detection. Finally, if transport processes are investigated, the standard permeant may interfere with the transport process under investigation or might even alter the barrier integrity by itself. Thus, independent, non-invasive techniques are needed to quantify the barrier integrity continuously during the experiment. Such techniques are available and are mainly based on the measurement of the transendothelial or transepithelial electrical resistance (TEER of barrier forming cells grown on porous membranes. Simple devices using two sets of electrodes (so-called Voltohmeters are widely used. In addition, an easy-to-use physical technique called impedance spectroscopy allows the continuous analysis of both the TEER and the electrical capacitance giving additional information about the barrier properties of cells grown on permeable membranes. This technique is useful as a quality control

Pointlike Inclusion Interactions in Tubular Membranes

NARCIS (Netherlands)

Vahid Belarghou, A.; Idema, T.

2016-01-01

Membrane tubes and tubular networks are ubiquitous in living cells. Inclusions like proteins are vital for both the stability and the dynamics of such networks. These inclusions interact via the curvature deformations they impose on the membrane. We analytically study the resulting membrane

A Role for Tubular Necroptosis in Cisplatin-Induced AKI

Science.gov (United States)

Xu, Yanfang; Ma, Huabin; Shao, Jing; Wu, Jianfeng; Zhou, Linying; Zhang, Zhirong; Wang, Yuze; Huang, Zhe; Ren, Junming; Liu, Suhuan; Chen, Xiangmei

2015-01-01

Cell death and inflammation in the proximal tubules are the hallmarks of cisplatin-induced AKI, but the mechanisms underlying these effects have not been fully elucidated. Here, we investigated whether necroptosis, a type of programmed necrosis, has a role in cisplatin-induced AKI. We found that inhibition of any of the core components of the necroptotic pathway—receptor-interacting protein 1 (RIP1), RIP3, or mixed lineage kinase domain-like protein (MLKL)—by gene knockout or a chemical inhibitor diminished cisplatin-induced proximal tubule damage in mice. Similar results were obtained in cultured proximal tubular cells. Furthermore, necroptosis of cultured cells could be induced by cisplatin or by a combination of cytokines (TNF-α, TNF-related weak inducer of apoptosis, and IFN-γ) that were upregulated in proximal tubules of cisplatin-treated mice. However, cisplatin induced an increase in RIP1 and RIP3 expression in cultured tubular cells in the absence of cytokine release. Correspondingly, overexpression of RIP1 or RIP3 enhanced cisplatin-induced necroptosis in vitro. Notably, inflammatory cytokine upregulation in cisplatin-treated mice was partially diminished in RIP3- or MLKL-deficient mice, suggesting a positive feedback loop involving these genes and inflammatory cytokines that promotes necroptosis progression. Thus, our data demonstrate that necroptosis is a major mechanism of proximal tubular cell death in cisplatin-induced nephrotoxic AKI. PMID:25788533

Dynamic model of a micro-tubular solid oxide fuel cell stack including an integrated cooling system

Science.gov (United States)

Hering, Martin; Brouwer, Jacob; Winkler, Wolfgang

2017-02-01

A novel dynamic micro-tubular solid oxide fuel cell (MT-SOFC) and stack model including an integrated cooling system is developed using a quasi three-dimensional, spatially resolved, transient thermodynamic, physical and electrochemical model that accounts for the complex geometrical relations between the cells and cooling-tubes. The modeling approach includes a simplified tubular geometry and stack design including an integrated cooling structure, detailed pressure drop and gas property calculations, the electrical and physical constraints of the stack design that determine the current, as well as control strategies for the temperature. Moreover, an advanced heat transfer balance with detailed radiative heat transfer between the cells and the integrated cooling-tubes, convective heat transfer between the gas flows and the surrounding structures and conductive heat transfer between the solid structures inside of the stack, is included. The detailed model can be used as a design basis for the novel MT-SOFC stack assembly including an integrated cooling system, as well as for the development of a dynamic system control strategy. The evaluated best-case design achieves very high electrical efficiency between around 75 and 55% in the entire power density range between 50 and 550 mW /cm2 due to the novel stack design comprising an integrated cooling structure.

Characterization of connective tissue growth factor expression in primary cultures of human tubular epithelial cells: modulation by hypoxia

NARCIS (Netherlands)

Kroening, Sven; Neubauer, Emily; Wullich, Bernd; Aten, Jan; Goppelt-Struebe, Margarete

2010-01-01

Kroening S, Neubauer E, Wullich B, Aten J, Goppelt-Struebe M. Characterization of connective tissue growth factor expression in primary cultures of human tubular epithelial cells: modulation by hypoxia. Am J Physiol Renal Physiol 298:F796-F806, 2010. First published December 23, 2009;

InGaP Heterojunction Barrier Solar Cells

Science.gov (United States)

Welser, Roger E. (Inventor)

2014-01-01

A new solar cell structure called a heterojunction barrier solar cell is described. As with previously reported quantum-well and quantum-dot solar cell structures, a layer of narrow band-gap material, such as GaAs or indium-rich InGaP, is inserted into the depletion region of a wide band-gap PN junction. Rather than being thin, however, the layer of narrow band-gap material is about 400-430 nm wide and forms a single, ultrawide well in the depletion region. Thin (e.g., 20-50 nm), wide band-gap InGaP barrier layers in the depletion region reduce the diode dark current. Engineering the electric field and barrier profile of the absorber layer, barrier layer, and p-type layer of the PN junction maximizes photogenerated carrier escape. This new twist on nanostructured solar cell design allows the separate optimization of current and voltage to maximize conversion efficiency.

Epoetin Delta Reduces Oxidative Stress in Primary Human Renal Tubular Cells

Directory of Open Access Journals (Sweden)

Annelies De Beuf

2010-01-01

Full Text Available Erythropoietin (EPO exerts (renal tissue protective effects. Since it is unclear whether this is a direct effect of EPO on the kidney or not, we investigated whether EPO is able to protect human renal tubular epithelial cells (hTECs from oxidative stress and if so which pathways are involved. EPO (epoetin delta could protect hTECs against oxidative stress by a dose-dependent inhibition of reactive oxygen species formation. This protective effect is possibly related to the membranous expression of the EPO receptor (EPOR since our data point to the membranous EPOR expression as a prerequisite for this protective effect. Oxidative stress reduction went along with the upregulation of renoprotective genes. Whilst three of these, heme oxygenase-1 (HO-1, aquaporin-1 (AQP-1, and B-cell CLL/lymphoma 2 (Bcl-2 have already been associated with EPO-induced renoprotection, this study for the first time suggests carboxypeptidase M (CPM, dipeptidyl peptidase IV (DPPIV, and cytoglobin (Cygb to play a role in this process.

The cholinergic pathway alleviates acute oxygen and glucose deprivation induced renal tubular cell injury by reducing the secretion of inflammatory medium of macrophages

Directory of Open Access Journals (Sweden)

Ming WU

2017-10-01

Full Text Available Objective To investigate the effects of cholinergic pathway on acute renal tubular cell injury induced by acute oxygen and glucose deprivation. Methods Rat kidney macrophages were isolated and cultured for constructing macrophages and renal epithelial cells co-cultivating model of oxygen-glucose deprivation (OGD, and the model cells were divided into three groups: OGD alone group, acetylcholine (ACh 100μmol/L+OGD group and ACh + galantamine (Gal 10μmol/L+OGD group. The cells underwent OGD treatment for 1 hour, and normally cultured for 24 hours. The expressions of TNF alpha, IL-1 beta, and IL-10 in supernatant fluid were detected by ELISA, the renal tubular cell viability was determined by MTT assay, the expression of acetylcholine esterase (AChE mRNA and protein were determined by RT-qPCR and Western blotting. The activity of AChE was determined by colorimetric method. Results The expressions of TNF alpha (pg/ml in OGD, Ach+OGD group, Ach+Gal+OGD groups were 140.2±44.81, 119.46±4.42 and 103.31±1.62 respectively (P0.05; The values of renal tubular cell proliferation were 55.02%±6.28%, 66.65%±6.47%, and 79.75%±4.22% respectively (P0.05; those of AchE protein were 0.66±0.07, 0.74±0.04 and 0.67±0.06 respectively (P>0.05; The activity of AChE (kU/L was 0.51±0.02, 0.35±0.05 and 0.32±0.04 respectively (P=0.001, 0.001 and 0.368. Conclusions ACh and Gal could inhibit the secretion of inflammatory mediators and cholinesterase activity and can reduce the acute hypoxic renal tubular cell injury. The modulation of the cholinergic pathway in macrophages may be the important treatment method for acute renal injury in the future. DOI: 10.11855/j.issn.0577-7402.2017.08.01

Resveratrol prevents high glucose-induced epithelial-mesenchymal transition in renal tubular epithelial cells by inhibiting NADPH oxidase/ROS/ERK pathway.

Science.gov (United States)

He, Ting; Guan, Xu; Wang, Song; Xiao, Tangli; Yang, Ke; Xu, Xinli; Wang, Junping; Zhao, Jinghong

2015-02-15

Resveratrol (RSV) is reported to have renoprotective activity against diabetic nephropathy, while the mechanisms underlying its function have not been fully elucidated. In this study, we investigate the effect and related mechanism of RSV against high glucose-induced epithelial to mesenchymal transition (EMT) in human tubular epithelial cells (HK-2). A typical EMT is induced by high glucose in HK-2 cells, accompanied by increased levels of reactive oxygen species (ROS). RSV exhibits a strong ability to inhibit high glucose-induced EMT by decreasing intracellular ROS levels via down-regulation of NADPH oxidase subunits NOX1 and NOX4. The activation of extracellular signal-regulated kinase (ERK1/2) is found to be involved in high glucose-induced EMT in HK-2 cells. RSV, like NADPH oxidase inhibitor diphenyleneiodonium, can block ERK1/2 activation induced by high glucose. Our results demonstrate that RSV is a potent agent against high glucose-induced EMT in renal tubular cells via inhibition of NADPH oxidase/ROS/ERK1/2 pathway. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Expandable tubulars for use in geologic structures

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Spray, Jeffery A.; Svedeman, Steven; Walter, David; Mckeighan, Peter; Siebanaler, Shane; Dewhurst, Peter; Hobson, Steven; Foss, Doug; Wirz, Holger; Sharpe, Aaron; Apostal, Michael

2014-08-12

An expandable tubular includes a plurality of leaves formed from sheet material that have curved surfaces. The leaves extend around a portion or fully around the diameter of the tubular structure. Some of the adjacent leaves of the tubular are coupled together. The tubular is compressed to a smaller diameter so that it can be inserted through previously deployed tubular assemblies. Once the tubular is properly positioned, it is deployed and coupled or not coupled to a previously deployed tubular assembly. The tubular is useful for all types of wells and boreholes.

Proximal tubular hypertrophy and enlarged glomerular and proximal tubular urinary space in obese subjects with proteinuria.

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Ana Tobar

Full Text Available BACKGROUND: Obesity is associated with glomerular hyperfiltration, increased proximal tubular sodium reabsorption, glomerular enlargement and renal hypertrophy. A single experimental study reported an increased glomerular urinary space in obese dogs. Whether proximal tubular volume is increased in obese subjects and whether their glomerular and tubular urinary spaces are enlarged is unknown. OBJECTIVE: To determine whether proximal tubules and glomerular and tubular urinary space are enlarged in obese subjects with proteinuria and glomerular hyperfiltration. METHODS: Kidney biopsies from 11 non-diabetic obese with proteinuria and 14 non-diabetic lean patients with a creatinine clearance above 50 ml/min and with mild or no interstitial fibrosis were retrospectively analyzed using morphometric methods. The cross-sectional area of the proximal tubular epithelium and lumen, the volume of the glomerular tuft and of Bowman's space and the nuclei number per tubular profile were estimated. RESULTS: Creatinine clearance was higher in the obese than in the lean group (P=0.03. Proteinuria was similarly increased in both groups. Compared to the lean group, the obese group displayed a 104% higher glomerular tuft volume (P=0.001, a 94% higher Bowman's space volume (P=0.003, a 33% higher cross-sectional area of the proximal tubular epithelium (P=0.02 and a 54% higher cross-sectional area of the proximal tubular lumen (P=0.01. The nuclei number per proximal tubular profile was similar in both groups, suggesting that the increase in tubular volume is due to hypertrophy and not to hyperplasia. CONCLUSIONS: Obesity-related glomerular hyperfiltration is associated with proximal tubular epithelial hypertrophy and increased glomerular and tubular urinary space volume in subjects with proteinuria. The expanded glomerular and urinary space is probably a direct consequence of glomerular hyperfiltration. These effects may be involved in the pathogenesis of obesity

The effect of acyclovir on the tubular secretion of creatinine in vitro

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Aleksa Katarina

2010-12-01

Full Text Available Abstract Background While generally well tolerated, severe nephrotoxicity has been observed in some children receiving acyclovir. A pronounced elevation in plasma creatinine in the absence of other clinical manifestations of overt nephrotoxicity has been frequently documented. Several drugs have been shown to increase plasma creatinine by inhibiting its renal tubular secretion rather than by decreasing glomerular filtration rate (GFR. Creatinine and acyclovir may be transported by similar tubular transport mechanisms, thus, it is plausible that in some cases, the observed increase in plasma creatinine may be partially due to inhibition of tubular secretion of creatinine, and not solely due to decreased GFR. Our objective was to determine whether acyclovir inhibits the tubular secretion of creatinine. Methods Porcine (LLC-PK1 and human (HK-2 renal proximal tubular cell monolayers cultured on microporous membrane filters were exposed to [2-14C] creatinine (5 μM in the absence or presence of quinidine (1E+03 μM, cimetidine (1E+03 μM or acyclovir (22 - 89 μM in incubation medium. Results Results illustrated that in evident contrast to quinidine, acyclovir did not inhibit creatinine transport in LLC-PK1 and HK-2 cell monolayers. Conclusions The results suggest that acyclovir does not affect the renal tubular handling of creatinine, and hence, the pronounced, transient increase in plasma creatinine is due to decreased GFR, and not to a spurious increase in plasma creatinine.

Downregulation of miR-205 modulates cell susceptibility to oxidative and endoplasmic reticulum stresses in renal tubular cells.

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Shiyo Muratsu-Ikeda

Full Text Available BACKGROUND: Oxidative stress and endoplasmic reticulum (ER stress play a crucial role in tubular damage in both acute kidney injury (AKI and chronic kidney disease (CKD. While the pathophysiological contribution of microRNAs (miRNA to renal damage has also been highlighted, the effect of miRNA on renal damage under oxidative and ER stresses conditions remains elusive. METHODS: We assessed changes in miRNA expression in the cultured renal tubular cell line HK-2 under hypoxia-reoxygenation-induced oxidative stress or ER stress using miRNA microarray assay and real-time RT-PCR. The pathophysiological effect of miRNA was evaluated by cell survival rate, intracellular reactive oxygen species (ROS level, and anti-oxidant enzyme expression in miRNA-inhibited HK-2 or miRNA-overexpressed HK-2 under these stress conditions. The target gene of miRNA was identified by 3'-UTR-luciferase assay. RESULTS: We identified 8 and 10 miRNAs whose expression was significantly altered by oxidative and ER stresses, respectively. Among these, expression of miR-205 was markedly decreased in both stress conditions. Functional analysis revealed that decreased miR-205 led to an increase in cell susceptibility to oxidative and ER stresses, and that this increase was associated with the induction of intracellular ROS and suppression of anti-oxidant enzymes. While increased miR-205 by itself made no change in cell growth or morphology, cell viability under oxidative or ER stress conditions was partially restored. Further, miR-205 bound to the 3'-UTR of the prolyl hydroxylase 1 (PHD1/EGLN2 gene and suppressed the transcription level of EGLN2, which modulates both intracellular ROS level and ER stress state. CONCLUSIONS: miR-205 serves a protective role against both oxidative and ER stresses via the suppression of EGLN2 and subsequent decrease in intracellular ROS. miR-205 may represent a novel therapeutic target in AKI and CKD associated with oxidative or ER stress in tubules.

Reliability of Tubular Joints

DEFF Research Database (Denmark)

Sørensen, John Dalsgaard; Thoft-Christensen, Palle

In this paper the preliminary results obtained by tests on tubular joints are presented. The joints are T-joints and the loading is static. It is the intention in continuation of these tests to perform tests on other types of joints (e.g. Y-joints) and also with dynamic loading. The purpose...... of the test is partly to obtain empirical data for the ultimate load-carrying capacity of tubular T-joints and partly to obtain some experience in performing tests with tubular joints. It is well known that tubular joints are usually designed in offshore engineering on the basis of empirical formulas obtained...... by experimental test results. Therefore, there is a need for performing experimental tests in this area....

Thermodynamic model and parametric analysis of a tubular SOFC module

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Campanari, Stefano

Solid oxide fuel cells (SOFCs) have been considered in the last years as one of the most promising technologies for very high-efficiency electric energy generation from natural gas, both with simple fuel cell plants and with integrated gas turbine-fuel cell systems. Among the SOFC technologies, tubular SOFC stacks with internal reforming have emerged as one of the most mature technology, with a serious potential for a future commercialization. In this paper, a thermodynamic model of a tubular SOFC stack, with natural gas feeding, internal reforming of hydrocarbons and internal air preheating is proposed. In the first section of the paper, the model is discussed in detail, analyzing its calculating equations and tracing its logical steps; the model is then calibrated on the available data for a recently demonstrated tubular SOFC prototype plant. In the second section of the paper, it is carried out a detailed parametric analysis of the stack working conditions, as a function of the main operating parameters. The discussion of the results of the thermodynamic and parametric analysis yields interesting considerations about partial load SOFC operation and load regulation, and about system design and integration with gas turbine cycles.

Uric Acid Induces Renal Inflammation via Activating Tubular NF-κB Signaling Pathway

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Zhou, Yang; Fang, Li; Jiang, Lei; Wen, Ping; Cao, Hongdi; He, Weichun; Dai, Chunsun; Yang, Junwei

2012-01-01

Inflammation is a pathologic feature of hyperuricemia in clinical settings. However, the underlying mechanism remains unknown. Here, infiltration of T cells and macrophages were significantly increased in hyperuricemia mice kidneys. This infiltration of inflammatory cells was accompanied by an up-regulation of TNF-α, MCP-1 and RANTES expression. Further, infiltration was largely located in tubular interstitial spaces, suggesting a role for tubular cells in hyperuricemia-induced inflammation. In cultured tubular epithelial cells (NRK-52E), uric acid, probably transported via urate transporter, induced TNF-α, MCP-1 and RANTES mRNA as well as RANTES protein expression. Culture media of NRK-52E cells incubated with uric acid showed a chemo-attractive ability to recruit macrophage. Moreover uric acid activated NF-κB signaling. The uric acid-induced up-regulation of RANTES was blocked by SN 50, a specific NF-κB inhibitor. Activation of NF-κB signaling was also observed in tubule of hyperuricemia mice. These results suggest that uric acid induces renal inflammation via activation of NF-κB signaling. PMID:22761883

Proximal tubular dysfunction as an indicator of chronic graft dysfunction

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N.O.S. Câmara

2009-03-01

Full Text Available New strategies are being devised to limit the impact of renal sclerosis on graft function. Individualization of immunosuppression, specifically the interruption of calcineurin-inhibitors has been tried in order to promote better graft survival once chronic graft dysfunction has been established. However, the long-term impact of these approaches is still not totally clear. Nevertheless, patients at higher risk for tubular atrophy and interstitial fibrosis (TA/IF development should be carefully monitored for tubular function as well as glomerular performance. Since tubular-interstitial impairment is an early event in TA/IF pathogenesis and associated with graft function, it seems reasonable that strategies directed at assessing tubular structural integrity and function would yield important functional and prognostic data. The measurement of small proteins in urine such as α-1-microglobulin, N-acetyl-beta-D-glucosaminidase, alpha/pi S-glutathione transferases, β-2 microglobulin, and retinol binding protein is associated with proximal tubular cell dysfunction. Therefore, its straightforward assessment could provide a powerful tool in patient monitoring and ongoing clinical assessment of graft function, ultimately helping to facilitate longer patient and graft survival associated with good graft function.

Abnormal expression and processing of uromodulin in Fabry disease reflects tubular cell storage alteration and is reversible by enzyme replacement therapy

Czech Academy of Sciences Publication Activity Database

Vyleťal, P.; Hůlková, H.; Živná, M.; Berná, L.; Novák, Petr; Elleder, M.; Kmoch, S.

2008-01-01

Roč. 31, č. 4 (2008), s. 508-517 ISSN 0141-8955 Institutional research plan: CEZ:AV0Z50200510 Keywords : uromodulin * fabry disease * tubular cell Subject RIV: EE - Microbiology, Virology Impact factor: 2.691, year: 2008

Cytocompatibility of a silk fibroin tubular scaffold

International Nuclear Information System (INIS)

Wang, Jiannan; Wei, Yali; Yi, Honggen; Liu, Zhiwu; Sun, Dan; Zhao, Huanrong

2014-01-01

Regenerated silk fibroin (SF) materials are increasingly used for tissue engineering applications. In order to explore the feasibility of a novel biomimetic silk fibroin tubular scaffold (SFTS) crosslinked by poly(ethylene glycol) diglycidyl ether (PEG-DE), biocompatibility with cells was evaluated. The novel biomimetic design of the SFTS consisted of three distinct layers: a regenerated SF intima, a silk braided media and a regenerated SF adventitia. The SFTS exhibited even silk fibroin penetration throughout the braid, forming a porous layered tube with superior mechanical, permeable and cell adhesion properties that are beneficial to vascular regeneration. Cytotoxicity and cell compatibility were tested on L929 cells and human umbilical vein endothelial cells (EA.hy926). DNA content analysis, scanning electron and confocal microscopies and MTT assay showed no inhibitory effects on DNA replication. Cell morphology, viability and proliferation were good for L929 cells, and satisfactory for EA.hy926 cells. Furthermore, the suture retention strength of the SFTS was about 23 N and the Young's modulus was 0.2–0.3 MPa. Collectively, these data demonstrate that PEG-DE crosslinked SFTS possesses the appropriate cytocompatibility and mechanical properties for use as vascular scaffolds as an alternative to vascular autografts. - Highlights: • A PEG-DE cross-linked small caliber porous silk fibroin tubular scaffold (SFTS) • PEG-DE cross-linked SF film had no inhibitory effect on DNA replication of cells. • Cells cultured on the SFTS showed good morphology, cell viability and proliferative activity. • SFTS would be beneficial to endothelialization. • SFTS had good suture retention strength and flexibility

78 FR 14361 - U.S. Steel Tubular Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United...

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2013-03-05

... Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United States Steel Corporation, Mckeesport, PA; Notice of Initiation of Investigation To Terminate Certification of Eligibility Pursuant to... Tubular Products, McKeesport Tubular Operations Division, Subsidiary of United States Steel Corporation...

Significance of downregulation of renal organic cation transporter (SLC47A1 in cisplatin-induced proximal tubular injury

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Mizuno T

2015-07-01

Full Text Available Tomohiro Mizuno,1–3 Waichi Sato,2,3 Kazuhiro Ishikawa,4 Yuki Terao,1 Kazuo Takahashi,2 Yukihiro Noda,5 Yukio Yuzawa,2 Tadashi Nagamatsu1 1Department of Analytical Pharmacology, Meijo University Faculty of Pharmacy, Nagoya, 2Department of Nephrology, School of Medicine, Fujita Health University, Toyoake, 3Department of Nephrology, Nagoya University School of Medicine, Nagoya, 4Department of Neuropsychopharmacology and Hospital Pharmacy, Nagoya University Graduate School of Medicine, Nagoya, 5Division of Clinical Sciences and Neuropsychopharmacology, Meijo University Faculty of Pharmacy, Nagoya, Japan Background/aim: To elucidate the mechanism responsible for developing acute kidney injury in patients with diabetes mellitus, we also evaluated the issue of whether advanced glycation endproducts (AGEs influence the expressions of multi antimicrobial extrusion protein (MATE1/SLC47A1 in tubular cells. Materials and methods: To detect changing expression of MATE1/SLC47A1 in dose- and time-dependent manners, human proximal tubular epithelial cells were incubated with AGE-aggregated-human serum albumin. As a function assay for MATE1/SLC47A1, human proximal tubular epithelial cells were incubated with cisplatin or carboplatin. Results: On incubation with AGEs, the expressions of MATE1/SLC47A1 were decreased in tubular cells. In addition, the toxicities of cisplatin were increased in tubular cells that had been pretreated with AGEs. However, the toxicities of carboplatin were smaller than that of cisplatin in proximal tubular epithelial cells. Conclusion: The expression of the MATE1/SLC47A1 is decreased by AGEs, which increases the risk for proximal tubular injury. Keywords: advanced glycation endproducts, cisplatin, SLC47A1, diabetes mellitus, acute kidney injury

Distal renal tubular acidosis

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... this disorder. Alternative Names Renal tubular acidosis - distal; Renal tubular acidosis type I; Type I RTA; RTA - distal; Classical RTA Images Kidney anatomy Kidney - blood and urine flow References Bose A, Monk RD, Bushinsky DA. Kidney ...

Synergy between type 1 fimbriae expression and C3 opsonisation increases internalisation of E. coli by human tubular epithelial cells.

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Li, Ke; Zhou, Wuding; Hong, Yuzhi; Sacks, Steven H; Sheerin, Neil S

2009-03-31

Bacterial infection of the urinary tract is a common clinical problem with E. coli being the most common urinary pathogen. Bacterial uptake into epithelial cells is increasingly recognised as an important feature of infection. Bacterial virulence factors, especially fimbrial adhesins, have been conclusively shown to promote host cell invasion. Our recent study reported that C3 opsonisation markedly increases the ability of E. coli strain J96 to internalise into human proximal tubular epithelial cells via CD46, a complement regulatory protein expressed on host cell membrane. In this study, we further assessed whether C3-dependent internalisation by human tubular epithelial cells is a general feature of uropathogenic E. coli and investigated features of the bacterial phenotype that may account for any heterogeneity. In 31 clinical isolates of E. coli tested, C3-dependent internalisation was evident in 10 isolates. Type 1 fimbriae mediated-binding is essential for C3-dependent internalisation as shown by phenotypic association, type 1 fimbrial blockade with soluble ligand (mannose) and by assessment of a type 1 fimbrial mutant. we propose that efficient internalisation of uropathogenic E. coli by the human urinary tract depends on co-operation between type 1 fimbriae-mediated adhesion and C3 receptor -ligand interaction.

78 FR 37584 - U.S. Steel Tubular Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United...

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2013-06-21

... make the following certification: All workers of U.S. Steel Tubular Products, McKeesport Tubular... Products, Inc., Mckeesport Tubular Operations Division, Subsidiary of United States Steel Corporation, Mckeesport, Pennsylvania; Notice of Amended Certification Pursuant to Section 221 of the Trade Act of 1974...

Albumin Overload and PINK1/Parkin Signaling-Related Mitophagy in Renal Tubular Epithelial Cells.

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Tan, Jin; Xie, Qi; Song, Shuling; Miao, Yuyang; Zhang, Qiang

2018-03-01

BACKGROUND Albumin, as a major urinary protein component, is a risk factor for chronic kidney disease progression. Mitochondrial dysfunction is one of the main causes of albumin-induced proximal tubule cells injury. Mitophagy is considered as a pivotal protective mechanism for the elimination of dysfunctional mitochondria. The objective of this research was to determine whether albumin overload-induced mitochondrial dysfunction can activate PINK1/Parkin-mediated mitophagy in renal tubular epithelial cells (TECs). MATERIAL AND METHODS Immunofluorescence assay and Western blot assay were used to detect the effects of albumin overload on autophagy marker protein LC3. Transmission electron microscopy and Western blot assay were used to investigate the role of albumin in mitochondrial injury. Western blot assay and co-localization of acidic lysosomes and mitochondria assay were employed to detect the activation of mitophagy induced by albumin. Finally, we explored the role of PINK1/Parkin signaling in albumin-induced mitophagy by inhibiting mitophagy by knockdown of PARK2 (Parkin) level. RESULTS Immunofluorescence and Western blot results showed that the expression level of LC3-II increased, and the maximum increase point was observed after 8 h of albumin treatment. Transmission electron microscopy results demonstrated that albumin overload-induced mitochondrial injury and quantity of autophagosomes increased. Additionally, expression of PINK1 and cytosolic cytochrome C increased and mitochondria cytochrome C decreased in the albumin group. The co-localization of acidic lysosomes and mitochondria demonstrated that the number of albumin overload-induced mitophagy-positive dots increased. The transient transfection of PARK2 siRNA result showed knockdown of the expression level of PARK2 can inhibit mitophagy induced by albumin. CONCLUSIONS In conclusion, our study suggests that mitochondrial dysfunction activates the PINK1/Parkin signaling and mitophagy in renal tubular

Paricalcitol attenuates lipopolysaccharide-induced inflammation and apoptosis in proximal tubular cells through the prostaglandin E₂ receptor EP4

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Yu Ah Hong

2017-06-01

Full Text Available Background: Vitamin D is considered to exert a protective effect on various renal diseases but its underlying molecular mechanism remains poorly understood. This study aimed to determine whether paricalcitol attenuates inflammation and apoptosis during lipopolysaccharide (LPS-induced renal proximal tubular cell injury through the prostaglandin E₂ (PGE₂ receptor EP4. Methods: Human renal tubular epithelial (HK-2 cells were pretreated with paricalcitol (2 ng/mL for 1 hour and exposed to LPS (1 μg/mL. The effects of paricalcitol pretreatment in relation to an EP4 blockade using AH-23848 or EP4 small interfering RNA (siRNA were investigated. Results: The expression of cyclooxygenase-2, PGE₂, and EP4 were significantly increased in LPS-exposed HK-2 cells treated with paricalcitol compared with cells exposed to LPS only. Paricalcitol prevented cell death induced by LPS exposure, and the cotreatment of AH-23848 or EP4 siRNA offset these cell-protective effects. The phosphorylation and nuclear translocation of p65 nuclear factor-kappaB (NF-κB were decreased and the phosphorylation of Akt was increased in LPS-exposed cells with paricalcitol treatment. AH-23848 or EP4 siRNA inhibited the suppressive effects of paricalcitol on p65 NF-κB nuclear translocation and the activation of Akt. The production of proinflammatory cytokines and the number of terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling-positive cells were attenuated by paricalcitol in LPS exposed HK-2 cells. The cotreatment with an EP4 antagonist abolished these anti-inflammatory and antiapoptotic effects. Conclusion: EP4 plays a pivotal role in anti-inflammatory and antiapoptotic effects through Akt and NF-κB signaling after paricalcitol pretreatment in LPS-induced renal proximal tubule cell injury.

Electrochemical cell structure including an ionomeric barrier

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Lambert, Timothy N.; Hibbs, Michael

2017-06-20

An apparatus includes an electrochemical half-cell comprising: an electrolyte, an anode; and an ionomeric barrier positioned between the electrolyte and the anode. The anode may comprise a multi-electron vanadium phosphorous alloy, such as VP.sub.x, wherein x is 1-5. The electrochemical half-cell is configured to oxidize the vanadium and phosphorous alloy to release electrons. A method of mitigating corrosion in an electrochemical cell includes disposing an ionomeric barrier in a path of electrolyte or ion flow to an anode and mitigating anion accumulation on the surface of the anode.

3-MCPD 1-Palmitate Induced Tubular Cell Apoptosis In Vivo via JNK/p53 Pathways

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Liu, Man; Huang, Guoren; Wang, Thomas T.Y.; Sun, Xiangjun; Yu, Liangli (Lucy)

2016-01-01

Fatty acid esters of 3-chloro-1, 2-propanediol (3-MCPD esters) are a group of processing induced food contaminants with nephrotoxicity but the molecular mechanism(s) remains unclear. This study investigated whether and how the JNK/p53 pathway may play a role in the nephrotoxic effect of 3-MCPD esters using 3-MCPD 1-palmitate (MPE) as a probe compound in Sprague Dawley rats. Microarray analysis of the kidney from the Sprague Dawley rats treated with MPE, using Gene Ontology categories and KEGG pathways, revealed that MPE altered mRNA expressions of the genes involved in the mitogen-activated protein kinase (JNK and ERK), p53, and apoptotic signal transduction pathways. The changes in the mRNA expressions were confirmed by qRT-PCR and Western blot analyses and were consistent with the induction of tubular cell apoptosis as determined by histopathological, TUNEL, and immunohistochemistry analyses in the kidneys of the Sprague Dawley rats. Additionally, p53 knockout attenuated the apoptosis, and the apoptosis-related protein bax expression and cleaved caspase-3 activation induced by MPE in the p53 knockout C57BL/6 mice, whereas JNK inhibitor SP600125 but not ERK inhibitor U0126 inhibited MPE-induced apoptosis, supporting the conclusion that JNK/p53 might play a critical role in the tubular cell apoptosis induced by MPE and other 3-MCPD fatty acid esters. PMID:27008853

In vitro generation of renal tubular epithelial cells from fibroblasts: implications for precision and regenerative medicine in nephrology.

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Wyatt, Christina M; Dubois, Nicole

2017-02-01

Prior efforts to generate renal epithelial cells in vitro have relied on pluripotent or bone marrow-derived mesenchymal stem cells. A recent publication in Nature Cell Biology describes the generation of induced tubular epithelial cells from fibroblasts, potentially offering a novel platform for personalized drug toxicity screening and in vitro disease modeling. This report serves as a promising proof of principle study and opens future research directions, including the optimization of the reprogramming process, efficient translation to adult human fibroblasts, and the generation of highly specific functional renal cell types. Copyright © 2016 International Society of Nephrology. Published by Elsevier Inc. All rights reserved.

Tubular nanostructured materials for bioapplications

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Xie, Jining; Chen, Linfeng; Srivatsan, Malathi; Varadan, Vijay K.

2009-03-01

Tubular nanomaterials possess hollow structures as well as high aspect ratios. In addition to their unique physical and chemical properties induced by their nanoscale dimensions, their inner voids and outer surfaces make them ideal candidates for a number of biomedical applications. In this work, three types of tubular nanomaterials including carbon nanotubes, hematite nanotubes, and maghemite nanotubes, were synthesized by different chemical techniques. Their structural and crystalline properties were characterized. For potential bioapplications of tubular nanomaterials, experimental investigations were carried out to demonstrate the feasibility of using carbon nanotubes, hematite nanotubes, and maghemite nanotubes in glucose sensing, neuronal growth, and drug delivery, respectively. Preliminary results show the promise of tubular nanomaterials in future biomedical applications.

Effect of cyclosporine therapy in transplanted patients-diagnostic values of tubular markers

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Todor Gruev

2003-09-01

Full Text Available The introduction of cyclosporine A (CsA into the clinical practice has resulted in a major improvement in the short-term outcomes of solid organ transplantation and treatment of autoimune diseases. Chronic ScA nephrotoxicity has been described in kidneys of recepients of renal and other organ allografts. However, the exact mechanism underlying the development of fibrosis in chronic CsA nephrotoxicity has remained poorly understood. Evaluation with the validation data set showed that noninvasive urine protein differentiation might be a useful diagnostic strategy in nephrology. Over the past decade numerous studies in patients after transplantation have demonstrated that renal tubular cell injury after a toxic insult, results in sloughing of tubular debris and cell into the tubular lumen with eventual obstruction of tubular flow, increased intratubular pressure and backleak of glomerular filtrate out of the tubule. Urinary enzymes and low molecular proteins have been recommended as useful markers for the detection of changes in the kidney tissue in cases after renal transplantation. The aim of our study was to monitor the concentration and eventual nephrotoxic effect of Cyclosporine A using the concentration of low molecular proteins α-1-microglobulin and β−2-microglobulin, serum Cystatin C, as well as the concentration of isoform of GST-α and π.

High pressure operation of tubular solid oxide fuel cells and their intergration with gas turbines

Energy Technology Data Exchange (ETDEWEB)

Haynes, C.; Wepfer, W.J. [Georgia Institute of Technology, Atlanta, GA (United States)

1996-12-31

Fossil fuels continue to be used at a rate greater than that of their natural formation, and the current byproducts from their use are believed to have a detrimental effect on the environment (e.g. global warming). There is thus a significant impetus to have cleaner, more efficient fuel consumption alternatives. Recent progress has led to renewed vigor in the development of fuel cell technology, which has been shown to be capable of producing high efficiencies with relatively benign exhaust products. The tubular solid oxide fuel cell developed by Westinghouse Electric Corporation has shown significant promise. Modeling efforts have been and are underway to optimize and better understand this fuel cell technology. Thus far, the bulk of modeling efforts has been for operation at atmospheric pressure. There is now interest in developing high-efficiency integrated gas turbine/solid oxide fuel cell systems. Such operation of fuel cells would obviously occur at higher pressures. The fuel cells have been successfully modeled under high pressure operation and further investigated as integrated components of an open loop gas turbine cycle.

THE FAILURE OF CHLOROFORM ADMINISTERED IN THE DRINKING WATER TO INDUCE RENAL TUBULAR CELL NEOPLASIA IN MALE F344/N RATS

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The failure of chloroform administered in drinking water to induce renal tubular cell neoplasia in male F344/N rats Chloroform (TCM) has been demonstrated to be a renal carcinogen in the male Osborne-Mendel rat when administered either by corn oil gavage or in drin...

Expression of Nestin, Vimentin, and NCAM by Renal Interstitial Cells after Ischemic Tubular Injury

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David Vansthertem

2010-01-01

Full Text Available This work explores the distribution of various markers expressed by interstitial cells in rat kidneys after ischemic injury (35 minutes during regeneration of S3 tubules of outer stripe of outer medulla (OSOM. Groups of experimental animals (n=4 were sacrificed every two hours during the first 24 hours post-ischemia as well as 2, 3, 7, 14 days post-ischemia. The occurrence of lineage markers was analyzed on kidney sections by immunohistochemistry and morphometry during the process of tubular regeneration. In postischemic kidneys, interstitial cell proliferation, assessed by 5-bromo-2′-deoxyuridine (BrdU and Proliferating Cell Nuclear Antigen (PCNA labeling, was prominent in outer medulla and reach a maximum between 24 and 72 hours after reperfusion. This population was characterized by the coexpression of vimentin and nestin. The density of -Neural Cell Adhesion Molecule (NCAM positive interstitial cells increased transiently (18–72 hours in the vicinity of altered tubules. We have also localized a small population of α-Smooth Muscle Actin (SMA-positive cells confined to chronically altered areas and characterized by a small proliferative index. In conclusion, we observed in the postischemic kidney a marked proliferation of interstitial cells that underwent transient phenotypical modifications. These interstitial cells could be implicated in processes leading to renal fibrosis.

Quantifying cellular mechanics and adhesion in renal tubular injury using single cell force spectroscopy.

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Siamantouras, Eleftherios; Hills, Claire E; Squires, Paul E; Liu, Kuo-Kang

2016-05-01

Tubulointerstitial fibrosis represents the major underlying pathology of diabetic nephropathy where loss of cell-to-cell adhesion is a critical step. To date, research has predominantly focussed on the loss of cell surface molecular binding events that include altered protein ligation. In the current study, atomic force microscopy single cell force spectroscopy (AFM-SCFS) was used to quantify changes in cellular stiffness and cell adhesion in TGF-β1 treated kidney cells of the human proximal tubule (HK2). AFM indentation of TGF-β1 treated HK2 cells showed a significant increase (42%) in the elastic modulus (stiffness) compared to control. Fluorescence microscopy confirmed that increased cell stiffness is accompanied by reorganization of the cytoskeleton. The corresponding changes in stiffness, due to F-actin rearrangement, affected the work of detachment by changing the separation distance between two adherent cells. Overall, our novel data quantitatively demonstrate a correlation between cellular elasticity, adhesion and early morphologic/phenotypic changes associated with tubular injury. Diabetes affects many patients worldwide. One of the long term problems is diabetic nephropathy. Here, the authors utilized atomic force microscopy single cell force spectroscopy (AFM- SCFS) to study cellular stiffness and cell adhesion after TGF1 treatment in human proximal tubule kidney cells. The findings would help further understand the overall disease mechanism in diabetic patients. Copyright © 2015 Elsevier Inc. All rights reserved.

Autophagy activation promotes removal of damaged mitochondria and protects against renal tubular injury induced by albumin overload.

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Tan, Jin; Wang, Miaohong; Song, Shuling; Miao, Yuyang; Zhang, Qiang

2018-01-10

Proteinuria (albuminuria) is an important cause of aggravating tubulointerstitial injury. Previous studies have shown that autophagy activation can alleviate renal tubular epithelial cell injury caused by urinary protein, but the mechanism is not clear. Here, we investigated the role of clearance of damaged mitochondria in this protective effect. We found that albumin overload induces a significant increase in turnover of LC3-II and decrease in p62 protein level in renal proximal tubular (HK-2) cells in vitro. Albumin overload also induces an increase in mitochondrial damage. ALC, a mitochondrial torpent, alleviates mitochondrial damage induced by albumin overload and also decreases autophagy, while mitochondrial damage revulsant CCCP further increases autophagy. Furthermore, pretreatment of HK-2 cells with rapamycin reduced the amount of damaged mitochondria and the level of apoptosis induced by albumin overload. In contrast, blocking autophagy with chloroquine exerted an opposite effect. Taken together, our results indicated autophagy activation promotes removal of damaged mitochondria and protects against renal tubular injury caused by albumin overload. This further confirms previous research that autophagy activation is an adaptive response in renal tubular epithelial cells after urinary protein overload.

Toxicological Significance of Renal Bcrp: Another Potential Transporter in the Elimination of Mercuric Ions from Proximal Tubular Cells

Science.gov (United States)

Bridges, Christy C.; Zalups, Rudolfs K.; Joshee, Lucy

2015-01-01

Secretion of inorganic mercury (Hg2+) from proximal tubular cells into the tubular lumen has been shown to involve the multidrug resistance-associated protein 2 (Mrp2). Considering similarities in localization and substrate specificity between Mrp2 and the breast cancer resistance protein (Bcrp), we hypothesize that Bcrp may also play a role in the proximal tubular secretion of mercuric species. In order to test this hypothesis, the uptake of Hg2+ was examined initially using inside-out membrane vesicles containing Bcrp. The results of these studies suggest that Bcrp may be capable of transporting certain conjugates of Hg2+. To further characterize the role of Bcrp in the handling of mercuric ions and in the induction of Hg2+-induced nephropathy, Sprague-Dawley and Bcrp knockout (bcrp−/−) rats were exposed intravenously to a non-nephrotoxic (0.5 μmol • kg−1), a moderately nephrotoxic (1.5 μmol • kg−1) or a significantly nephrotoxic (2.0 μmol • kg−1) dose of HgCl2. In general, the accumulation of Hg2+ was greater in organs of bcrp−/− rats than in Sprague-Dawley rats, suggesting that Bcrp may play a role in the export of Hg2+ from target cells. Within the kidney, cellular injury and necrosis was more severe in bcrp−/− rats than in controls. The pattern of necrosis, which was localized in the inner cortex and the outer stripe of the outer medulla was significantly different from that observed in Mrp2-deficient animals. These findings suggest that Bcrp may be involved in the cellular export of select mercuric species and that its role in this export may differ from that of Mrp2. PMID:25868844

Template-based fluoroethylenepropylene piezoelectrets with tubular channels for transducer applications

Science.gov (United States)

Altafim, Ruy Alberto Pisani; Qiu, Xunlin; Wirges, Werner; Gerhard, Reimund; Altafim, Ruy Alberto Corrêa; Basso, Heitor Cury; Jenninger, Werner; Wagner, Joachim

2009-07-01

We describe the concept, the fabrication, and the most relevant properties of a piezoelectric-polymer system: Two fluoroethylenepropylene (FEP) films with good electret properties are laminated around a specifically designed and prepared polytetrafluoroethylene (PTFE) template at 300 °C. After removing the PTFE template, a two-layer FEP film with open tubular channels is obtained. For electric charging, the two-layer FEP system is subjected to a high electric field. The resulting dielectric barrier discharges inside the tubular channels yield a ferroelectret with high piezoelectricity. d33 coefficients of up to 160 pC/N have already been achieved on the ferroelectret films. After charging at suitable elevated temperatures, the piezoelectricity is stable at temperatures of at least 130 °C. Advantages of the transducer films include ease of fabrication at laboratory or industrial scales, a wide range of possible geometrical and processing parameters, straightforward control of the uniformity of the polymer system, flexibility, and versatility of the soft ferroelectrets, and a large potential for device applications e.g., in the areas of biomedicine, communications, production engineering, sensor systems, environmental monitoring, etc.

Tubular lining material for pipelines having bends

Energy Technology Data Exchange (ETDEWEB)

Moringa, A.; Sakaguchi, Y.; Hyodo, M.; Yagi, I.

1987-03-24

A tubular lining material for pipelines having bends or curved portions comprises a tubular textile jacket made of warps and wefts woven in a tubular form overlaid with a coating of a flexible synthetic resin. It is applicable onto the inner surface of a pipeline having bends or curved portions in such manner that the tubular lining material with a binder onto the inner surface thereof is inserted into the pipeline and allowed to advance within the pipeline, with or without the aid of a leading rope-like elongated element, while turning the tubular lining material inside out under fluid pressure. In this manner the tubular lining material is applied onto the inner surface of the pipeline with the binder being interposed between the pipeline and the tubular lining material. The lining material is characterized in that a part of all of the warps are comprised of an elastic yarn around which, over the full length thereof, a synthetic fiber yarn or yarns have been left-and/or right-handedly coiled. This tubular lining material is particularly suitable for lining a pipeline having an inner diameter of 25-200 mm and a plurality of bends, such as gas service pipelines or house pipelines, without occurrence of wrinkles in the lining material in a bend.

Scaffold-Free Tubular Tissues Created by a Bio-3D Printer Undergo Remodeling and Endothelialization when Implanted in Rat Aortae

Science.gov (United States)

Itoh, Manabu; Nakayama, Koichi; Noguchi, Ryo; Kamohara, Keiji; Furukawa, Kojirou; Uchihashi, Kazuyoshi; Toda, Shuji; Oyama, Jun-ichi; Node, Koichi; Morita, Shigeki

2015-01-01

Background Small caliber vascular prostheses are not clinically available because synthetic vascular prostheses lack endothelial cells which modulate platelet activation, leukocyte adhesion, thrombosis, and the regulation of vasomotor tone by the production of vasoactive substances. We developed a novel method to create scaffold-free tubular tissue from multicellular spheroids (MCS) using a “Bio-3D printer”-based system. This system enables the creation of pre-designed three-dimensional structures using a computer controlled robotics system. With this system, we created a tubular structure and studied its biological features. Methods and Results Using a “Bio-3D printer,” we made scaffold-free tubular tissues (inner diameter of 1.5 mm) from a total of 500 MCSs (2.5× 104 cells per one MCS) composed of human umbilical vein endothelial cells (40%), human aortic smooth muscle cells (10%), and normal human dermal fibroblasts (50%). The tubular tissues were cultured in a perfusion system and implanted into the abdominal aortas of F344 nude rats. We assessed the flow by ultrasonography and performed histological examinations on the second (n = 5) and fifth (n = 5) day after implantation. All grafts were patent and remodeling of the tubular tissues (enlargement of the lumen area and thinning of the wall) was observed. A layer of endothelial cells was confirmed five days after implantation. Conclusions The scaffold-free tubular tissues made of MCS using a Bio-3D printer underwent remodeling and endothelialization. Further studies are warranted to elucidate the underlying mechanism of endothelialization and its function, as well as the long-term results. PMID:26325298

Scaffold-Free Tubular Tissues Created by a Bio-3D Printer Undergo Remodeling and Endothelialization when Implanted in Rat Aortae.

Science.gov (United States)

Itoh, Manabu; Nakayama, Koichi; Noguchi, Ryo; Kamohara, Keiji; Furukawa, Kojirou; Uchihashi, Kazuyoshi; Toda, Shuji; Oyama, Jun-Ichi; Node, Koichi; Morita, Shigeki

2015-01-01

Small caliber vascular prostheses are not clinically available because synthetic vascular prostheses lack endothelial cells which modulate platelet activation, leukocyte adhesion, thrombosis, and the regulation of vasomotor tone by the production of vasoactive substances. We developed a novel method to create scaffold-free tubular tissue from multicellular spheroids (MCS) using a "Bio-3D printer"-based system. This system enables the creation of pre-designed three-dimensional structures using a computer controlled robotics system. With this system, we created a tubular structure and studied its biological features. Using a "Bio-3D printer," we made scaffold-free tubular tissues (inner diameter of 1.5 mm) from a total of 500 MCSs (2.5× 104 cells per one MCS) composed of human umbilical vein endothelial cells (40%), human aortic smooth muscle cells (10%), and normal human dermal fibroblasts (50%). The tubular tissues were cultured in a perfusion system and implanted into the abdominal aortas of F344 nude rats. We assessed the flow by ultrasonography and performed histological examinations on the second (n = 5) and fifth (n = 5) day after implantation. All grafts were patent and remodeling of the tubular tissues (enlargement of the lumen area and thinning of the wall) was observed. A layer of endothelial cells was confirmed five days after implantation. The scaffold-free tubular tissues made of MCS using a Bio-3D printer underwent remodeling and endothelialization. Further studies are warranted to elucidate the underlying mechanism of endothelialization and its function, as well as the long-term results.

Additive Manufacturing of Patient-Customizable Scaffolds for Tubular Tissues Using the Melt-Drawing Method.

Science.gov (United States)

Tan, Yu Jun; Tan, Xipeng; Yeong, Wai Yee; Tor, Shu Beng

2016-11-03

Polymeric fibrous scaffolds for guiding cell growth are designed to be potentially used for the tissue engineering (TE) of tubular organs including esophagi, blood vessels, tracheas, etc. Tubular scaffolds were fabricated via melt-drawing of highly elastic poly(l-lactide-co-ε-caprolactone) (PLC) fibers layer-by-layer on a cylindrical mandrel. The diameter and length of the scaffolds are customizable via 3D printing of the mandrel. Thickness of the scaffolds was varied by changing the number of layers of the melt-drawing process. The morphology and tensile properties of the PLC fibers were investigated. The fibers were highly aligned with a uniform diameter. Their diameters and tensile properties were tunable by varying the melt-drawing speeds. These tailorable topographies and tensile properties show that the additive-based scaffold fabrication technique is customizable at the micro- and macro-scale for different tubular tissues. The merits of these scaffolds in TE were further shown by the finding that myoblast and fibroblast cells seeded onto the scaffolds in vitro showed appropriate cell proliferation and distribution. Human mesenchymal stem cells (hMSCs) differentiated to smooth muscle lineage on the microfibrous scaffolds in the absence of soluble induction factors, showing cellular shape modulation and scaffold elasticity may encourage the myogenic differentiation of stem cells.

Iatrogenic Digital Compromise with Tubular Dressings

Directory of Open Access Journals (Sweden)

Corre, Kenneth A

2009-08-01

Full Text Available Objective: This case report describes a digit amputation resulting from an improperly applied tubular dressing. The safe application of digital tubular dressings, and the rationale behind it, is detailed to raise emergency physician (EP awareness.Methods: We present a case report of a recent iatrogenic-induced digit ischemia caused by improperly applied tube gauze. We review the literature on the subject and the likely sources of poor outcomes presented. The proper application of tubular gauze dressings is then outlined.Conclusion: EPs and emergency department personnel must be educated on the safe application of tubular gauze dressings to avoid dire outcomes associated with improper applications.[WestJEM. 2009;10:190-192.

Electrolyte creepage barrier for liquid electrolyte fuel cells

Science.gov (United States)

Li, Jian [Alberta, CA; Farooque, Mohammad [Danbury, CT; Yuh, Chao-Yi [New Milford, CT

2008-01-22

A dielectric assembly for electrically insulating a manifold or other component from a liquid electrolyte fuel cell stack wherein the dielectric assembly includes a substantially impermeable dielectric member over which electrolyte is able to flow and a barrier adjacent the dielectric member and having a porosity of less than 50% and greater than 10% so that the barrier is able to measurably absorb and chemically react with the liquid electrolyte flowing on the dielectric member to form solid products which are stable in the liquid electrolyte. In this way, the barrier inhibits flow or creepage of electrolyte from the dielectric member to the manifold or component to be electrically insulated from the fuel cell stack by the dielectric assembly.

A radially accessible tubular in situ X-ray cell for spatially resolved operando scattering and spectroscopic studies of electrochemical energy storage devices

Energy Technology Data Exchange (ETDEWEB)

Liu, Hao; Allan, Phoebe K.; Borkiewicz, Olaf J.; Kurtz, Charles; Grey, Clare P.; Chapman, Karena W.; Chupas, Peter J.

2016-09-16

A tubularoperandoelectrochemical cell has been developed to allow spatially resolved X-ray scattering and spectroscopic measurements of individual cell components, or regions thereof, during device operation. These measurements are enabled by the tubular cell geometry, wherein the X-ray-transparent tube walls allow radial access for the incident and scattered/transmitted X-ray beam; by probing different depths within the electrode stack, the transformation of different components or regions can be resolved. The cell is compatible with a variety of synchrotron-based scattering, absorption and imaging methodologies. The reliability of the electrochemical cell and the quality of the resulting X-ray scattering and spectroscopic data are demonstrated for two types of energy storage: the evolution of the distribution of the state of charge of an Li-ion battery electrode during cycling is documented using X-ray powder diffraction, and the redistribution of ions between two porous carbon electrodes in an electrochemical double-layer capacitor is documented using X-ray absorption near-edge spectroscopy.

Molten carbonate fuel cell integral matrix tape and bubble barrier

International Nuclear Information System (INIS)

Reiser, C.A.; Maricle, D.L.

1983-01-01

A molten carbonate fuel cell matrix material is described made up of a matrix tape portion and a bubble barrier portion. The matrix tape portion comprises particles inert to molten carbonate electrolyte, ceramic particles and a polymeric binder, the matrix tape being flexible, pliable and having rubber-like compliance at room temperature. The bubble barrier is a solid material having fine porosity preferably being bonded to the matrix tape. In operation in a fuel cell, the polymer binder burns off leaving the matrix and bubble barrier providing superior sealing, stability and performance properties to the fuel cell stack

Drill pipes and casings utilizing multi-conduit tubulars

Energy Technology Data Exchange (ETDEWEB)

Curlett, H.B.

1989-01-24

A seal adapted for use with a multi-conduit well tubular, or the like, is described which consists of: a plate with fluid passages, each passage corresponding to an opening of a conduit of the multiconduit tubular, and a groove on the plate around each passage; and elastomer means partially embeddable into each groove for sealing each conduit of a tubular to a corresponding conduit of another similar tubular.

De novo expression of sodium-glucose cotransporter SGLT2 in Bowman's capsule coincides with replacement of parietal epithelial cell layer with proximal tubule-like epithelium.

Science.gov (United States)

Tabatabai, Niloofar M; North, Paula E; Regner, Kevin R; Kumar, Suresh N; Duris, Christine B; Blodgett, Amy B

2014-08-01

In kidney nephron, parietal epithelial cells line the Bowman's capsule and function as a permeability barrier for the glomerular filtrate. Bowman's capsule cells with proximal tubule epithelial morphology have been found. However, the effects of tubular metaplasia in Bowman's capsule on kidney function remain poorly understood. Sodium-glucose cotransporter 2 (SGLT2) plays a major role in reabsorption of glucose in the kidney and is expressed on brush border membrane (BBM) of epithelial cells in the early segment of the proximal tubule. We hypothesized that SGLT2 is expressed in tubularized Bowman's capsule and used our novel antibody to test this hypothesis. Immunohistochemical analysis was performed with our SGLT2 antibody on C57BL/6 mouse kidney prone to have tubularized Bowman's capsules. Cell membrane was examined with periodic acid-Schiff (PAS) stain. The results showed that SGLT2 was localized on BBM of the proximal tubules in young and adult mice. Bowman's capsules were lined mostly with normal brush border-less parietal epithelial cells in young mice, while they were almost completely covered with proximal tubule-like cells in adult mice. Regardless of age, SGLT2 was expressed on BBM of the tubularized Bowman's capsule but did not co-localize with nephrin in the glomerulus. SGLT2-expressing tubular cells expanded from the urinary pole toward the vascular pole of the Bowman's capsule. This study identified the localization of SGLT2 in the Bowman's capsule. Bowman's capsules with tubular metaplasia may acquire roles in reabsorption of filtered glucose and sodium.

Methylmercury inhibits gap junctional intercellular communication in primary cultures of rat proximal tubular cells

Energy Technology Data Exchange (ETDEWEB)

Yoshida, Minoru; Sumi, Yawara [Department of Chemistry, St. Marianna University School of Medicine, Kawasagi (Japan); Kujiraoka, Toru [Department of Physiology, St. Marianna University School of Medicine, Kawasagi (Japan); Hara, Masayuki [Department of Anatomy, St. Marianna University School of Medicine, Kawasagi (Japan); Nakazawa, Hirokazu [Department of Chemistry, Faculty of Sciences, Meisei University (Japan)

1998-03-01

Methylmercury (MeHg) causes renal injury in addition to central and peripheral neuropathy. To clarify the mechanism of nephrotoxicity by MeHg, we investigated the effect of this compound on intercellular communication through gap junction channels in primary cultures of rat renal proximal tubular cells. Twenty minutes after exposure to 30 {mu}M MeHg, gap junctional intercellular communication (GJIC), which was assessed by dye coupling, was markedly inhibited before appearance of cytotoxicity. When the medium containing MeHg was exchanged with MeHg-free medium, dye coupling recovered abruptly. However, the dye-coupling was abolished again 30 min after replacement with control medium, and the cells were damaged. Intracellular calcium concentration, [Ca{sup 2+}]{sub i}, which modulates the function of gap junctions, significantly increased following exposure of the cells to 30 {mu}M MeHg and returned to control level following replacement with MeHg-free medium. These results suggest that the inhibiting effect of MeHg on GJIC is related to the change in [Ca{sup 2+}]{sub i}, and may be involved in the pathogenesis of renal dysfunction. (orig.) With 5 figs., 23 refs.

Enhancing the Detection of Dysmorphic Red Blood Cells and Renal Tubular Epithelial Cells with a Modified Urinalysis Protocol.

Science.gov (United States)

Chu-Su, Yu; Shukuya, Kenichi; Yokoyama, Takashi; Lin, Wei-Chou; Chiang, Chih-Kang; Lin, Chii-Wann

2017-01-11

Urinary sediment is used to evaluate patients with possible urinary tract diseases. Currently, numerous protocols are applied to detect dysmorphic red blood cells (RBCs) and renal tubular epithelial cells (RTECs) in urinary sediment. However, distinct protocols are used by nephrologists and medical technologists for specimen concentration and observation, which leads to major discrepancies in the differential counts of formed elements such as dysmorphic RBCs and RTECs and might interfere with an accurate clinical diagnosis. To resolve these problems, we first tested a modified urinalysis protocol with an increased relative centrifuge force and concentration factor in 20 biopsy-confirmed glomerulonephritis patients with haematuria. We successfully improved the recovery ratio of dysmorphic RBCs in clinical specimens from 34.7% to 42.0% (P dysmorphic RBCs were detected using a bright field microscope, with results comparable to those using a standard phase contrast microscope. Finally, we applied Sternheimer stain to enhance the contrast of RTECs in the urinary sediments. We concluded that this modified urinalysis protocol significantly enhanced the quality of urinalysis.

Construction and characterization of an electrospun tubular scaffold for small-diameter tissue-engineered vascular grafts: a scaffold membrane approach.

Science.gov (United States)

Hu, Jin-Jia; Chao, Wei-Chih; Lee, Pei-Yuan; Huang, Chih-Hao

2012-09-01

Based on a postulate that the microstructure of a scaffold can influence that of the resulting tissue and hence its mechanical behavior, we fabricated a small-diameter tubular scaffold (∼3 mm inner diameter) that has a microstructure similar to the arterial media using a scaffold membrane approach. Scaffold membranes that contain randomly oriented, moderately aligned, or highly aligned fibers were fabricated by collecting electrospun poly([epsilon]-caprolactone) fibers on a grounded rotating drum at three different drum rotation speeds (250, 1000, and 1500 rpm). Membranes of each type were wrapped around a small-diameter mandrel to form the tubular scaffolds. Particularly, the tubular scaffolds with three different off-axis fiber angles (30, 45, and 60 degree) were formed using membranes that contain aligned fibers. These scaffolds were subjected to biaxial mechanical testing to examine the effects of fiber directions as well as the distribution of fiber orientations on their mechanical properties. The circumferential elastic modulus of the tubular scaffold was closely related to the fiber directions; the larger the off-axis fiber angle the greater the circumferential elastic modulus. The distribution of fiber orientations, on the other hand, manifested itself in the mechanical behavior via the Poisson effect. Similar to cell sheet-based vascular tissue engineering, tubular cell-seeded constructs were prepared by wrapping cell-seeded scaffold membranes, alleviating the difficulty associated with cell seeding in electrospun scaffolds. Histology of the construct illustrated that cells were aligned to the fiber directions in the construct, demonstrating the potential to control the microstructure of tissue-engineered vascular grafts using the electrospun scaffold membrane. Copyright © 2012 Elsevier Ltd. All rights reserved.

Epithelial-Mesenchymal Transition in Kidney Tubular Epithelial Cells Induced by Globotriaosylsphingosine and Globotriaosylceramide.

Directory of Open Access Journals (Sweden)

Yeo Jin Jeon

Full Text Available Fabry disease is a lysosomal storage disorder caused by deficiency of alpha-galactosidase A (α-gal A, which results in the deposition of globotriaosylceramide (Gb3 in the vascular endothelium. Globotriaosylsphingosine (lyso-Gb3, a deacylated Gb3, is also increased in the plasma of patients with Fabry disease. Renal fibrosis is a key feature of advanced Fabry disease patients. Therefore, we evaluated the association of Gb3 and lyso-Gb3 accumulation and the epithelial-mesenchymal transition (EMT on tubular epithelial cells of the kidney. In HK2 cells, exogenous treatments of Gb3 and lyso-Gb3 increased the expression of TGF-β, EMT markers (N-cadherin and α-SMA, and phosphorylation of PI3K/AKT, and decreased the expression of E-cadherin. Lyso-Gb3, rather than Gb3, strongly induced EMT in HK2 cells. In the mouse renal mesangial cell line, SV40 MES 13 cells, Gb3 strongly induced phenotype changes. The EMT induced by Gb3 was inhibited by enzyme α-gal A treatment, but EMT induced by lyso-Gb3 was not abrogated by enzyme treatment. However, TGF-β receptor inhibitor (TRI, SB525334 inhibited the activation of TGF-β and EMT markers in HK2 cells with Gb3 and lyso-Gb3 treatments. This study suggested that increased plasma lyso-Gb3 has a crucial role in the development of renal fibrosis through the cell-specific induction of the EMT in Fabry disease, and that TRI treatment, alongside enzyme replacement therapy, could be a potential therapeutic option for patients with Fabry disease.

Folded tubular photometer for atmospheric measurements of NO2 and NO

Science.gov (United States)

Birks, John W.; Andersen, Peter C.; Williford, Craig J.; Turnipseed, Andrew A.; Strunk, Stanley E.; Ennis, Christine A.; Mattson, Erick

2018-05-01

We describe and characterize a modular folded tubular photometer for making direct measurements of the concentrations of nitrogen dioxide (NO2) and specify how this method could be extended to measure other pollutants such as sulfur dioxide (SO2), ozone (O3), and black carbon particulate matter. Direct absorbance measurements using this photometer can be made across the spectral range from the ultraviolet (UV) to the near infrared. The absorbance cell makes use of modular components (tubular detection cells and mirror cubes) that allow construction of path lengths of up to 2 m or more while maintaining low cell volumes. The long path lengths and low cell volumes enable sensitive detection of ambient air pollutants down to low part-per-billion levels for gas species and aerosol extinctions down to 1 Mm-1, corresponding to ˜ 0.1 µg m-3 for black carbon particulates. Pressure equalization throughout the stages of the absorbance measurement is shown to be critical to accurate measurements of analyte concentrations. The present paper describes the application of this photometer to direct measurements of nitrogen dioxide (NO2) and the incorporation of design features that also enable measurement of nitric oxide (NO) in the same instrument. Excellent agreement for ambient measurements along an urban roadside was found for both NO2 and NO measured by the folded tubular photometer compared to existing standard techniques. Compared to commonly used methods for measurements of NOx species, the advantages of this approach include (1) an absolute quantification for NO2 based on the Beer-Lambert law, thereby greatly reducing the frequency at which calibrations are required; (2) the direct measurement of NO2 concentration without prior conversion to NO as is required for the commonly used chemiluminescence method; (3) the use of modular components that allow construction of absorbance detection cells of varying lengths for extending the dynamic range of concentrations that can

Cancer cells remodel themselves and vasculature to overcome the endothelial barrier.

Science.gov (United States)

Shenoy, Anitha K; Lu, Jianrong

2016-10-01

Metastasis refers to the spread of cancer cells from a primary tumor to distant organs mostly via the bloodstream. During the metastatic process, cancer cells invade blood vessels to enter circulation, and later exit the vasculature at a distant site. Endothelial cells that line blood vessels normally serve as a barrier to the movement of cells into or out of the blood. It is thus critical to understand how metastatic cancer cells overcome the endothelial barrier. Epithelial cancer cells acquire increased motility and invasiveness through epithelial-to-mesenchymal transition (EMT), which enables them to move toward vasculature. Cancer cells also express a variety of adhesion molecules that allow them to attach to vascular endothelium. Finally, cancer cells secrete or induce growth factors and cytokines to actively prompt vascular hyperpermeability that compromises endothelial barrier function and facilitates transmigration of cancer cells through the vascular wall. Elucidation of the mechanisms underlying metastatic dissemination may help develop new anti-metastasis therapeutics. Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

Augmenter of liver regeneration inhibits TGF-β1-induced renal tubular epithelial-to-mesenchymal transition via suppressing TβR II expression in vitro

International Nuclear Information System (INIS)

Liao, Xiao-hui; Zhang, Ling; Chen, Guo-tao; Yan, Ru-yu; Sun, Hang; Guo, Hui; Liu, Qi

2014-01-01

Tubular epithelial-to-mesenchymal transition (EMT) plays a crucial role in the progression of renal tubular interstitial fibrosis (TIF), which subsequently leads to chronic kidney disease (CKD) and eventually, end-stage renal disease (ESRD). We propose that augmenter of liver regeneration (ALR), a member of the newly discovered ALR/Erv1 protein family shown to ameliorate hepatic fibrosis, plays a similar protective role in renal tubular cells and has potential as a new treatment option for CKD. Here, we showed that recombinant human ALR (rhALR) inhibits EMT in renal tubular cells by antagonizing activation of the transforming growth factor-β1 (TGF-β1) signaling pathway. Further investigation revealed that rhALR suppresses the expression of TGF-β receptor type II (TβR II) and significantly alleviates TGF-β1-induced phosphorylation of Smad2 and nuclear factor-κB (NF-κB). No apparent adverse effects were observed upon the addition of rhALR alone to cells. These findings collectively suggest that ALR plays a role in inhibiting progression of renal tubular EMT, supporting its potential utility as an effective antifibrotic strategy to reverse TIF in CKD. - Highlights: • ALR is involved in the pathological progression of renal EMT in NRK-52E cells. • ALR suppresses the expression of TβRII and the phosphorylation of Smad2 and NF-κB. • ALR plays a role in inhibiting progression of renal tubular EMT

Augmenter of liver regeneration inhibits TGF-β1-induced renal tubular epithelial-to-mesenchymal transition via suppressing TβR II expression in vitro

Energy Technology Data Exchange (ETDEWEB)

Liao, Xiao-hui [Department of Nephrology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010 (China); Zhang, Ling, E-mail: lindazhang8508@hotmail.com [Department of Nephrology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010 (China); Chen, Guo-tao; Yan, Ru-yu [Department of Nephrology, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010 (China); Sun, Hang; Guo, Hui [Institute for Viral Hepatitis, Key Laboratory of Molecular Biology for Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010 (China); Liu, Qi, E-mail: txzzliuqi@163.com [Institute for Viral Hepatitis, Key Laboratory of Molecular Biology for Infectious Diseases, The Second Affiliated Hospital, Chongqing Medical University, Chongqing 400010 (China)

2014-10-01

Tubular epithelial-to-mesenchymal transition (EMT) plays a crucial role in the progression of renal tubular interstitial fibrosis (TIF), which subsequently leads to chronic kidney disease (CKD) and eventually, end-stage renal disease (ESRD). We propose that augmenter of liver regeneration (ALR), a member of the newly discovered ALR/Erv1 protein family shown to ameliorate hepatic fibrosis, plays a similar protective role in renal tubular cells and has potential as a new treatment option for CKD. Here, we showed that recombinant human ALR (rhALR) inhibits EMT in renal tubular cells by antagonizing activation of the transforming growth factor-β1 (TGF-β1) signaling pathway. Further investigation revealed that rhALR suppresses the expression of TGF-β receptor type II (TβR II) and significantly alleviates TGF-β1-induced phosphorylation of Smad2 and nuclear factor-κB (NF-κB). No apparent adverse effects were observed upon the addition of rhALR alone to cells. These findings collectively suggest that ALR plays a role in inhibiting progression of renal tubular EMT, supporting its potential utility as an effective antifibrotic strategy to reverse TIF in CKD. - Highlights: • ALR is involved in the pathological progression of renal EMT in NRK-52E cells. • ALR suppresses the expression of TβRII and the phosphorylation of Smad2 and NF-κB. • ALR plays a role in inhibiting progression of renal tubular EMT.

Parametric exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack through finite-volume model

International Nuclear Information System (INIS)

Calise, F.; Ferruzzi, G.; Vanoli, L.

2009-01-01

This paper presents a very detailed local exergy analysis of a tubular Solid Oxide Fuel Cell (SOFC) stack. In particular, a complete parametric analysis has been carried out, in order to assess the effects of the synthesis/design parameters on the local irreversibilities in the components of the stack. A finite-volume axial-symmetric model of the tubular internal reforming Solid Oxide Fuel Cell stack under investigation has been used. The stack consists of: SOFC tubes, tube-in-tube pre-reformer and tube and shell catalytic burner. The model takes into account the effects of heat/mass transfer and chemical/electrochemical reactions. The model allows one to predict the performance of a SOFC stack once a series of design and operative parameters are fixed, but also to investigate the source and localization of inefficiency. To this scope, an exergy analysis was implemented. The SOFC tube, the pre-reformer and the catalytic burner are discretized along their longitudinal axes. Detailed models of the kinetics of the reforming, catalytic combustion and electrochemical reactions are implemented. Pressure drops, convection heat transfer and overvoltages are calculated on the basis of the work previously developed by the authors. The heat transfer model includes the contribution of thermal radiation, so improving the models previously used by the authors. Radiative heat transfer is calculated on the basis of the slice-to-slice configuration factors and corresponding radiosities. On the basis of this thermochemical model, an exergy analysis has been carried out, in order to localize the sources and the magnitude of irreversibilities along the components of the stack. In addition, the main synthesis/design variables were varied in order to assess their effect on the exergy destruction within the component to which the parameter directly refers ('endogenous' contribution) and on the exergy destruction of all remaining components ('exogenous' contribution). Then, this analysis

Development of Partial Tubular Flat Knitting Fabric Composite Preform

Directory of Open Access Journals (Sweden)

Jiang Wei Qing

2016-01-01

Full Text Available After building some structures of partial tubular flat knitting fabric composite preform, the influencing factor on tubular section was analyzed and the fabric was knitted selectively. The partial tubular flat knitting fabric composite preform were Knitted by changing different yarn, row number and two-sided partial tubular flat knitting fabric. Multilayer sheet would be got after hot pressing and it has big market prospects and good application value.

Reliability Analysis of Tubular Joints in Offshore Structures

DEFF Research Database (Denmark)

Thoft-Christensen, Palle; Sørensen, John Dalsgaard

1987-01-01

Reliability analysis of single tubular joints and offshore platforms with tubular joints is" presented. The failure modes considered are yielding, punching, buckling and fatigue failure. Element reliability as well as systems reliability approaches are used and illustrated by several examples....... Finally, optimal design of tubular.joints with reliability constraints is discussed and illustrated by an example....

Drill pipes and casings utilizing multi-conduit tubular; Flerkanals roerstreng

Energy Technology Data Exchange (ETDEWEB)

Curlett, H.B.

1997-04-23

The invention relates to a multi-conduit tubular having fluid conduits and electrical conduits, with associated surface fluid and electrical commutators, and downhole sensors for providing surface monitors with instantaneous formation data. Each tubular includes a plurality of uniform linear conduits there through, with a gasket seal plate interposed between joined tubular for assuring a high pressure seal between joined conduits. the seal plate includes an intermediate electrical connector for connecting electrical conduit connectors of one tubular to another. A coupling collar with uniform diameter internal coarse and fine threads joins the tubular ends having similar threads by differential thread action without respective tubular rotation. Each tubular end includes an inter-engaging index recess and index lug, and drive recesses and lugs for maintaining angular registry of the tubular string and for driving one drill tubular with another. A fluid commutator includes a rotating shaft with passages connected to the tubular conduits, and rotating in a manifold having annular grooves in communication with the shaft passages and external fluid sources. An adaptor couples each commutator shaft passage to one or more tubular conduits. Slip rings on a quill shaft and stationary brush means provide electrical continuity from the electrical conduit wires to surface equipment. A cross-over sub includes formation parameter sensors and telemetry equipment in a blocked off portion of a fluid conduit. An annular accumulator connected with the well bore annulus applies a pressure thereto in response to downhole sensors to change the effective density of the drill mud. The multi-conduit tubular is further adapted for use as a well casing to provide downhole access of a plurality of fluids and electrical parameter sensors. 28 figs.

A sphingolipid-dependent diffusion barrier confines ER stress to the yeast mother cell

Science.gov (United States)

Clay, Lori; Caudron, Fabrice; Denoth-Lippuner, Annina; Boettcher, Barbara; Buvelot Frei, Stéphanie; Snapp, Erik Lee; Barral, Yves

2014-01-01

In many cell types, lateral diffusion barriers compartmentalize the plasma membrane and, at least in budding yeast, the endoplasmic reticulum (ER). However, the molecular nature of these barriers, their mode of action and their cellular functions are unclear. Here, we show that misfolded proteins of the ER remain confined into the mother compartment of budding yeast cells. Confinement required the formation of a lateral diffusion barrier in the form of a distinct domain of the ER-membrane at the bud neck, in a septin-, Bud1 GTPase- and sphingolipid-dependent manner. The sphingolipids, but not Bud1, also contributed to barrier formation in the outer membrane of the dividing nucleus. Barrier-dependent confinement of ER stress into the mother cell promoted aging. Together, our data clarify the physical nature of lateral diffusion barriers in the ER and establish the role of such barriers in the asymmetric segregation of proteotoxic misfolded proteins during cell division and aging. DOI: http://dx.doi.org/10.7554/eLife.01883.001 PMID:24843009

Setting plug & abandonment barriers with minimum removal of tubulars

OpenAIRE

Nessa, Jon Olav

2012-01-01

Master's thesis in Petroleum engineering The useful life of an offshore well is determined by the reserves which it contacts, the pressure support within the reservoir and the continued integrity of the wellbore. When a well has reached the end of its lifetime, plugging operations have to be conducted before permanent abandonment. Conventional Plug and Abandonment (P&A) operations will often require removing a section of the casing in order to create cross sectional barriers for well aband...

Diabetes increases susceptibility of primary cultures of rat proximal tubular cells to chemically induced injury

International Nuclear Information System (INIS)

Zhong Qing; Terlecky, Stanley R.; Lash, Lawrence H.

2009-01-01

Diabetic nephropathy is characterized by increased oxidative stress and mitochondrial dysfunction. In the present study, we prepared primary cultures of proximal tubular (PT) cells from diabetic rats 30 days after an ip injection of streptozotocin and compared their susceptibility to oxidants (tert-butyl hydroperoxide, methyl vinyl ketone) and a mitochondrial toxicant (antimycin A) with that of PT cells isolated from age-matched control rats, to test the hypothesis that PT cells from diabetic rats exhibit more cellular and mitochondrial injury than those from control rats when exposed to these toxicants. PT cells from diabetic rats exhibited higher basal levels of reactive oxygen species (ROS) and higher mitochondrial membrane potential, demonstrating that the PT cells maintain the diabetic phenotype in primary culture. Incubation with either the oxidants or mitochondrial toxicant resulted in greater necrotic and apoptotic cell death, greater evidence of morphological damage, greater increases in ROS, and greater decreases in mitochondrial membrane potential in PT cells from diabetic rats than in those from control rats. Pretreatment with either the antioxidant N-acetyl-L-cysteine or a catalase mimetic provided equivalent protection of PT cells from both diabetic and control rats. Despite the greater susceptibility to oxidative and mitochondrial injury, both cytoplasmic and mitochondrial glutathione concentrations were markedly higher in PT cells from diabetic rats, suggesting an upregulation of antioxidant processes in diabetic kidney. These results support the hypothesis that primary cultures of PT cells from diabetic rats are a valid model in which to study renal cellular function in the diabetic state.

Interplay between autophagy and apoptosis in lead(II)-induced cytotoxicity of primary rat proximal tubular cells.

Science.gov (United States)

Chu, Bing-Xin; Fan, Rui-Feng; Lin, Shu-Qian; Yang, Du-Bao; Wang, Zhen-Yong; Wang, Lin

2018-05-01

Autophagy and apoptosis are two different biological processes that determine cell fates. We previously reported that autophagy inhibition and apoptosis induction are involved in lead(II)-induced cytotoxicity in primary rat proximal tubular (rPT) cells, but the interplay between them remains to be elucidated. Firstly, data showed that lead(II)-induced elevation of LC3-II protein levels can be significantly modulated by 3-methyladenine or rapamycin; moreover, protein levels of Autophagy-related protein 5 (Atg5) and Beclin-1 were markedly up-regulated by lead(II) treatment, demonstrating that lead(II) could promote the autophagosomes formation in rPT cells. Next, we applied three pharmacological agents and genetic method targeting the early stage of autophagy to validate that enhancement of autophagosomes formation can inhibit lead(II)-induced apoptotic cell death in rPT cells. Simultaneously, lead(II) inhibited the autophagic degradation of rPT cells, while the addition of autophagic degradation inhibitor bafilomycin A1 aggravated lead(II)-induced apoptotic death in rPT cells. Collectively, this study provided us a good model to know about the dynamic process of lead(II)-induced autophagy in rPT cells, and the interplay between autophagy and apoptosis highlights a new sight into the mechanism of lead(II)-induced nephrotoxicity. Copyright © 2018. Published by Elsevier Inc.

Edaravone Protects against Methylglyoxal-Induced Barrier Damage in Human Brain Endothelial Cells

Science.gov (United States)

Tóth, Andrea E.; Walter, Fruzsina R.; Bocsik, Alexandra; Sántha, Petra; Veszelka, Szilvia; Nagy, Lajos; Puskás, László G.; Couraud, Pierre-Olivier; Takata, Fuyuko; Dohgu, Shinya; Kataoka, Yasufumi; Deli, Mária A.

2014-01-01

Background Elevated level of reactive carbonyl species, such as methylglyoxal, triggers carbonyl stress and activates a series of inflammatory responses leading to accelerated vascular damage. Edaravone is the active substance of a Japanese medicine, which aids neurological recovery following acute brain ischemia and subsequent cerebral infarction. Our aim was to test whether edaravone can exert a protective effect on the barrier properties of human brain endothelial cells (hCMEC/D3 cell line) treated with methylglyoxal. Methodology Cell viability was monitored in real-time by impedance-based cell electronic sensing. The barrier function of the monolayer was characterized by measurement of resistance and flux of permeability markers, and visualized by immunohistochemistry for claudin-5 and β-catenin. Cell morphology was also examined by holographic phase imaging. Principal Findings Methylglyoxal exerted a time- and dose-dependent toxicity on cultured human brain endothelial cells: a concentration of 600 µM resulted in about 50% toxicity, significantly reduced the integrity and increased the permeability of the barrier. The cell morphology also changed dramatically: the area of cells decreased, their optical height significantly increased. Edaravone (3 mM) provided a complete protection against the toxic effect of methylglyoxal. Co-administration of edaravone restored cell viability, barrier integrity and functions of brain endothelial cells. Similar protection was obtained by the well-known antiglycating molecule, aminoguanidine, our reference compound. Conclusion These results indicate for the first time that edaravone is protective in carbonyl stress induced barrier damage. Our data may contribute to the development of compounds to treat brain endothelial dysfunction in carbonyl stress related diseases. PMID:25033388

Edaravone protects against methylglyoxal-induced barrier damage in human brain endothelial cells.

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Andrea E Tóth

Full Text Available Elevated level of reactive carbonyl species, such as methylglyoxal, triggers carbonyl stress and activates a series of inflammatory responses leading to accelerated vascular damage. Edaravone is the active substance of a Japanese medicine, which aids neurological recovery following acute brain ischemia and subsequent cerebral infarction. Our aim was to test whether edaravone can exert a protective effect on the barrier properties of human brain endothelial cells (hCMEC/D3 cell line treated with methylglyoxal.Cell viability was monitored in real-time by impedance-based cell electronic sensing. The barrier function of the monolayer was characterized by measurement of resistance and flux of permeability markers, and visualized by immunohistochemistry for claudin-5 and β-catenin. Cell morphology was also examined by holographic phase imaging.Methylglyoxal exerted a time- and dose-dependent toxicity on cultured human brain endothelial cells: a concentration of 600 µM resulted in about 50% toxicity, significantly reduced the integrity and increased the permeability of the barrier. The cell morphology also changed dramatically: the area of cells decreased, their optical height significantly increased. Edaravone (3 mM provided a complete protection against the toxic effect of methylglyoxal. Co-administration of edaravone restored cell viability, barrier integrity and functions of brain endothelial cells. Similar protection was obtained by the well-known antiglycating molecule, aminoguanidine, our reference compound.These results indicate for the first time that edaravone is protective in carbonyl stress induced barrier damage. Our data may contribute to the development of compounds to treat brain endothelial dysfunction in carbonyl stress related diseases.

Role of IGFBP7 in Diabetic Nephropathy: TGF-β1 Induces IGFBP7 via Smad2/4 in Human Renal Proximal Tubular Epithelial Cells.

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Jun Watanabe

Full Text Available Tubular injury is one of the important determinants of progressive renal failure in diabetic nephropathy (DN, and TGF-β1 has been implicated in the pathogenesis of tubulointerstitial disease that characterizes proteinuric renal disease. The aim of this study was to identify novel therapeutic target molecules that play a role in the tubule damage of DN. We used an LC-MS/MS-based proteomic technique and human renal proximal epithelial cells (HRPTECs. Urine samples from Japanese patients with type 2 diabetes (n = 46 were used to quantify the candidate protein. Several proteins in HRPTECs in cultured media were observed to be driven by TGF-β1, one of which was 33-kDa IGFBP7, which is a member of IGFBP family. TGF-β1 up-regulated the expressions of IGFBP7 mRNA and protein in a dose- and time-dependent fashion via Smad2 and 4, but not MAPK pathways in HRPTECs. In addition, the knockdown of IGFBP7 restored the TGF-β1-induced epithelial to mesenchymal transition (EMT. In the immunohistochemical analysis, IGFBP7 was localized to the cytoplasm of tubular cells but not that of glomerular cells in diabetic kidney. Urinary IGFBP7 levels were significantly higher in the patients with macroalbuminuria and were correlated with age (r = 0.308, p = 0.037, eGFR (r = -0.376, p = 0.01, urinary β2-microglobulin (r = 0.385, p = 0.008, and urinary N-acetyl-beta-D-glucosaminidase (NAG (r = 0.502, p = 0.000. A multivariate regression analysis identified urinary NAG and age as determinants associated with urinary IGFBP7 levels. In conclusion, our data suggest that TGF-β1 enhances IGFBP7 via Smad2/4 pathways, and that IGFBP7 might be involved in the TGF-β1-induced tubular injury in DN.

Multiple metabolic hits converge on CD36 as novel mediator of tubular epithelial apoptosis in diabetic nephropathy.

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Katalin Susztak

2005-02-01

Full Text Available Diabetic nephropathy (DNP is a common complication of type 1 and type 2 diabetes mellitus and the most common cause of kidney failure. While DNP manifests with albuminuria and diabetic glomerulopathy, its progression correlates best with tubular epithelial degeneration (TED and interstitial fibrosis. However, mechanisms leading to TED in DNP remain poorly understood.We found that expression of scavenger receptor CD36 coincided with proximal tubular epithelial cell (PTEC apoptosis and TED specifically in human DNP. High glucose stimulated cell surface expression of CD36 in PTECs. CD36 expression was necessary and sufficient to mediate PTEC apoptosis induced by glycated albumins (AGE-BSA and CML-BSA and free fatty acid palmitate through sequential activation of src kinase, and proapoptotic p38 MAPK and caspase 3. In contrast, paucity of expression of CD36 in PTECs in diabetic mice with diabetic glomerulopathy was associated with normal tubular epithelium and the absence of tubular apoptosis. Mouse PTECs lacked CD36 and were resistant to AGE-BSA-induced apoptosis. Recombinant expression of CD36 in mouse PTECs conferred susceptibility to AGE-BSA-induced apoptosis.Our findings suggest a novel role for CD36 as an essential mediator of proximal tubular apoptosis in human DNP. Because CD36 expression was induced by glucose in PTECs, and because increased CD36 mediated AGE-BSA-, CML-BSA-, and palmitate-induced PTEC apoptosis, we propose a two-step metabolic hit model for TED, a hallmark of progression in DNP.

Renal tubular dysfunction nephrocalcinosis in a patient with BetaThalassemia Minor

International Nuclear Information System (INIS)

Prabahar, M.R.; Jain, M.; Chandrasekaran, V.; Indumathi, E.; Soundrarajan, P.

2008-01-01

Thalassemia is a hereditary anemia resulting from defect in hemoglobinproduction. Beta thalassemia is due to impaired production. Beta thalassemiais due to impaired production of beta globin chains, leading to a relativeexcess of alpha globin chains. The term beta thalassemia minor is used todescribe heterozygotes, who carry one normal beta globin and one betathalassemic allele. The vast majority of these patients are asymptomatic.However, a variety of renal tubular abnormalities including hypercaliuria,hypomagnesemia with renal magnesium wasting, decreased tubular absorption ofphosphorous, hypouricemia with renal uric acid wasting, renal glycosuria andtubular proteinuria have been described even in patients with betathalassemia minor. We here in report a 24-year old patient who was found tohave thalassemia minor and nephrocalcinosis with evidence of renal tubulardysfunction. Investigations revealed normal renal function, hypercalciuria,reduced tubular reabsorption of phosphorous, hypomagnesemia and renalmagnesium wasting. Screening for aminoaciduria was found to be negative. Anacid loading test revealed normal urinary acidification. Ultrasonogram of theabdomen revealed nephrocalcinosis and splenomegaly. Detailed work up foranemia showed normal white cell and platelet count while peripheral smearshowed microcytic hypochromic anemia with few target cells. Hemoglobinelectrophoresis revealed hemoglobin A of 92%, hemoglobin A2 of 6.2% andhemoglobin F of 1.8% consistent with beta thalassemia minor. Her parentalscreening was normal. A diagnosis of beta thalassemia minor with renaltubular dysfunction was made and the patient was started on thiazidediuretics to reduce hypercalciuria and advised regular follow-up. (author)

Folded tubular photometer for atmospheric measurements of NO2 and NO

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J. W. Birks

2018-05-01

Full Text Available We describe and characterize a modular folded tubular photometer for making direct measurements of the concentrations of nitrogen dioxide (NO2 and specify how this method could be extended to measure other pollutants such as sulfur dioxide (SO2, ozone (O3, and black carbon particulate matter. Direct absorbance measurements using this photometer can be made across the spectral range from the ultraviolet (UV to the near infrared. The absorbance cell makes use of modular components (tubular detection cells and mirror cubes that allow construction of path lengths of up to 2 m or more while maintaining low cell volumes. The long path lengths and low cell volumes enable sensitive detection of ambient air pollutants down to low part-per-billion levels for gas species and aerosol extinctions down to 1 Mm−1, corresponding to  ∼  0.1 µg m−3 for black carbon particulates. Pressure equalization throughout the stages of the absorbance measurement is shown to be critical to accurate measurements of analyte concentrations. The present paper describes the application of this photometer to direct measurements of nitrogen dioxide (NO2 and the incorporation of design features that also enable measurement of nitric oxide (NO in the same instrument. Excellent agreement for ambient measurements along an urban roadside was found for both NO2 and NO measured by the folded tubular photometer compared to existing standard techniques. Compared to commonly used methods for measurements of NOx species, the advantages of this approach include (1 an absolute quantification for NO2 based on the Beer–Lambert law, thereby greatly reducing the frequency at which calibrations are required; (2 the direct measurement of NO2 concentration without prior conversion to NO as is required for the commonly used chemiluminescence method; (3 the use of modular components that allow construction of absorbance detection cells of varying lengths for extending the

Mesenchymal stem cells attenuate blood-brain barrier leakage after cerebral ischemia in mice.

Science.gov (United States)

Cheng, Zhuo; Wang, Liping; Qu, Meijie; Liang, Huaibin; Li, Wanlu; Li, Yongfang; Deng, Lidong; Zhang, Zhijun; Yang, Guo-Yuan

2018-05-03

Ischemic stroke induced matrixmetallo-proteinase-9 (MMP-9) upregulation, which increased blood-brain barrier permeability. Studies demonstrated that mesenchymal stem cell therapy protected blood-brain barrier disruption from several cerebrovascular diseases. However, the underlying mechanism was largely unknown. We therefore hypothesized that mesenchymal stem cells reduced blood-brain barrier destruction by inhibiting matrixmetallo-proteinase-9 and it was related to intercellular adhesion molecule-1 (ICAM-1). Adult ICR male mice (n = 118) underwent 90-min middle cerebral artery occlusion and received 2 × 10 5 mesenchymal stem cell transplantation. Neurobehavioral outcome, infarct volume, and blood-brain barrier permeability were measured after ischemia. The relationship between myeloperoxidase (MPO) activity and ICAM-1 release was further determined. We found that intracranial injection of mesenchymal stem cells reduced infarct volume and improved behavioral function in experimental stroke models (p mesenchymal stem cell-treated mice compared to the control group following ischemia (p cells and myeloperoxidase activity were decreased in mesenchymal stem cell-treated mice (p mesenchymal stem cell therapy attenuated blood-brain barrier disruption in mice after ischemia. Mesenchymal stem cells attenuated the upward trend of MMP-9 and potentially via downregulating ICAM-1 in endothelial cells. Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK) pathway may influence MMP-9 expression of neutrophils and resident cells, and ICAM-1 acted as a key factor in the paracrine actions of mesenchymal stem cell.

Analysis of infiltration through a clay radon barrier at an UMTRA disposal cell

International Nuclear Information System (INIS)

1991-01-01

An infiltration study was initiated in January 1988 to assess the percent saturation in, and infiltration through, clay radon barriers of typical Uranium Mill Tailings Remedial Action (UMTRA) Project disposal cells. Predicting infiltration through the radon barrier is necessary to evaluate whether the disposal cell will comply with the proposed US Environmental Protection Agency (EPA) groundwater protection standards (40 CFR 192). The groundwater standards require demonstrating that tailings seepage will not cause background concentrations or maximum concentration limits (MCLs) to be exceeded at the downgradient edge of the disposal facility (the point of compliance, or POC). This demonstration generally consists of incorporating the predicted seepage flux and the concentration of the specific hazardous constituents into a contaminant transport model, and predicting the resultant concentrations at the POC. The infiltration study consisted of a field investigation to evaluate moisture conditions in the radon barrier of the completed Shiprock, New Mexico, UMTRA Project disposal cell and previously completed UMTRA Project disposal cells at Clive, Utah, and Burrell, Pennsylvania. Coring was conducted to measure percent saturation profiles in the radon barriers at these disposal cells. In addition, a detailed investigation of the Shiprock radon barrier was conducted to establish the effects of meteorological stresses on moisture conditions in the filter layer and radon barrier. The Shiprock infiltration study was also intended to characterize hydraulic gradients and operational unsaturated hydraulic conductivities in the radon barrier

Determination of Clara cell protein urinary elimination as a marker of tubular dysfunction.

Science.gov (United States)

Martín-Granado, Ascensión; Vázquez-Moncholí, Carmen; Luis-Yanes, María Isabel; López-Méndez, Marisela; García-Nieto, Víctor

2009-04-01

Clara cell 16-kDa protein (CC16) is a protein expressed primarily by the bronchial cells. It is rapidly eliminated by glomerular filtration, reabsorbed almost entirely, and catabolized in proximal tubule cells. To date, normal values for urinary CC16 in healthy children have not been determined. We have studied 63 pediatric patients (mean age 8.17 +/- 3.91 years) and 31 healthy children (control group; mean age 8.83 +/- 3.65 years). In the control group, the CC16/creatinine ratio was 1.22 +/- 1.52 microg/g. In 16 out of 31 control children, the value of the ratio was zero. Fourteen patients (22.2%) showed a high CC16/creatinine ratio; in contrast, among these same patients, the ratio N-acetyl-beta-D: -glucosaminidase (NAG)/creatinine was elevated in seven cases (11.1%) and the ratio beta2-microglobulin/creatinine was elevated in seven cases (11.1%). The three parameters were in agreement in 51 patients (80.9%). Among the patients, the CC16/creatinine ratio was correlated with both the beta2-microglobulin/creatinina ratio (r = 0.76, P < 0.001) and the NAG/creatinine ratio (r = 0.6, P < 0.001). Our findings indicate that CC16 is a good marker of proximal tubular function in childhood. The highest observed values were in children with proximal tubulopathies, in children with chronic renal failure, and in those treated with cyclosporine.

Preparation and characterization of coaxial halloysite/polypyrrole tubular nanocomposites for electrochemical energy storage

International Nuclear Information System (INIS)

Yang Chao; Liu Peng; Zhao Yongqing

2010-01-01

Halloysite nanotubes/polypyrrole (HNTs/PPy) nanocomposites with coaxial tubular morphology for use as electrode materials for supercapacitors were synthesized by the in situ chemical oxidative polymerization method based on self-assembled monolayer amine-functionalized HNTs. The HNTs/PPy coaxial tubular nanocomposites were characterized with transmission electron microscope (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), electrical conductivity measurement at different temperatures, cyclic voltammetry (CV), and galvanostatic charge-discharge measurements. The coaxial tubular nanocomposites showed their greatest conductivity at room temperature and a weak temperature dependence of the conductivity from 298 K to 423 K. A maximum discharge capacity of 522 F/g after correcting for the weight percent of the PPy phase at a current density of 5 mA cm -2 in a 0.5 M Na 2 SO 4 electrolyte could be achieved in a half-cell setup configuration for the HNTs/PPy composites electrode, suggesting its potential application in electrode materials for electrochemical capacitors.

Preparation and characterization of coaxial halloysite/polypyrrole tubular nanocomposites for electrochemical energy storage

Energy Technology Data Exchange (ETDEWEB)

Yang Chao [State Key Laboratory of Applied Organic Chemistry and Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Tianshui South Road 222, Lanzhou 730000 (China); Liu Peng, E-mail: pliu@lzu.edu.c [State Key Laboratory of Applied Organic Chemistry and Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Tianshui South Road 222, Lanzhou 730000 (China); Zhao Yongqing [State Key Laboratory of Applied Organic Chemistry and Institute of Polymer Science and Engineering, College of Chemistry and Chemical Engineering, Lanzhou University, Tianshui South Road 222, Lanzhou 730000 (China)

2010-09-01

Halloysite nanotubes/polypyrrole (HNTs/PPy) nanocomposites with coaxial tubular morphology for use as electrode materials for supercapacitors were synthesized by the in situ chemical oxidative polymerization method based on self-assembled monolayer amine-functionalized HNTs. The HNTs/PPy coaxial tubular nanocomposites were characterized with transmission electron microscope (TEM), X-ray diffraction (XRD), thermogravimetric analysis (TGA), electrical conductivity measurement at different temperatures, cyclic voltammetry (CV), and galvanostatic charge-discharge measurements. The coaxial tubular nanocomposites showed their greatest conductivity at room temperature and a weak temperature dependence of the conductivity from 298 K to 423 K. A maximum discharge capacity of 522 F/g after correcting for the weight percent of the PPy phase at a current density of 5 mA cm{sup -2} in a 0.5 M Na{sub 2}SO{sub 4} electrolyte could be achieved in a half-cell setup configuration for the HNTs/PPy composites electrode, suggesting its potential application in electrode materials for electrochemical capacitors.

Thermal CFD Analysis of Tubular Light Guides

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Ondřej Šikula

2013-12-01

Full Text Available Tubular light guides are applicable for daylighting of windowless areas in buildings. Despite their many positive indoor climate aspects they can also present some problems with heat losses and condensation. A computer CFD model focused on the evaluation of temperature distribution and air flow inside tubular light guides of different dimensions was studied. The physical model of the tested light guides of lengths more than 0.60 m proves shows that Rayleigh numbers are adequate for a turbulent air flow. The turbulent model was applied despite the small heat flux differences between the turbulent and laminar model. The CFD simulations resulted into conclusions that the growing ratio of length/diameter increases the heat transmission loss/linear transmittance as much as by 50 percent. Tubular light guides of smaller diameters have lower heat transmission losses compared to the wider ones of the same lengths with the same outdoor temperature being taken into account. The simulation results confirmed the thermal bridge effect of the tubular light guide tube inside the insulated flat roof details. The thermal transmittance of the studied light guides in the whole roof area was substituted with the point thermal bridges. This substitution gives possibility for simple thermal evaluation of the tubular light pipes in roof constructions.

Experiments in MARIUS on HTR tubular fuel with loose particles

Energy Technology Data Exchange (ETDEWEB)

Bosser, R; Langlet, G

1972-06-15

The work described on HTR tubular fuel with loose particles is the first part of a program in three points. The cell is the same in the three experiments, only particles in the fuel container are changed. The aim of the experiment is to achieve the buckling in a critical facility. A description of the techniques of measurements, calculations, and results are presented.

Luminal nucleotides are tonic inhibitors of renal tubular transport

DEFF Research Database (Denmark)

Leipziger, Jens Georg

2011-01-01

PURPOSE OF REVIEW: Extracellular ATP is an essential local signaling molecule in all organ systems. In the kidney, purinergic signaling is involved in an array of functions and this review highlights those of relevance for renal tubular transport. RECENT FINDINGS: Purinergic receptors are express...... discovered as an important signaling compartment in which local purinergic signaling determines an inhibitory tone for renal tubular transport. Blocking components of this system leads to tubular hyper-absorption, volume retention and elevated blood pressure.......PURPOSE OF REVIEW: Extracellular ATP is an essential local signaling molecule in all organ systems. In the kidney, purinergic signaling is involved in an array of functions and this review highlights those of relevance for renal tubular transport. RECENT FINDINGS: Purinergic receptors are expressed...... in all renal tubular segments and their stimulation generally leads to transport inhibition. Recent evidence has identified the tubular lumen as a restricted space for purinergic signaling. The concentrations of ATP in the luminal fluids are sufficiently high to inflict a tonic inhibition of renal...

Myosin XI-dependent formation of tubular structures from endoplasmic reticulum isolated from tobacco cultured BY-2 cells.

Science.gov (United States)

Yokota, Etsuo; Ueda, Haruko; Hashimoto, Kohsuke; Orii, Hidefumi; Shimada, Tomoo; Hara-Nishimura, Ikuko; Shimmen, Teruo

2011-05-01

The reticular network of the endoplasmic reticulum (ER) consists of tubular and lamellar elements and is arranged in the cortical region of plant cells. This network constantly shows shape change and remodeling motion. Tubular ER structures were formed when GTP was added to the ER vesicles isolated from tobacco (Nicotiana tabacum) cultured BY-2 cells expressing ER-localized green fluorescent protein. The hydrolysis of GTP during ER tubule formation was higher than that under conditions in which ER tubule formation was not induced. Furthermore, a shearing force, such as the flow of liquid, was needed for the elongation/extension of the ER tubule. The shearing force was assumed to correspond to the force generated by the actomyosin system in vivo. To confirm this hypothesis, the S12 fraction was prepared, which contained both cytosol and microsome fractions, including two classes of myosins, XI (175-kD myosin) and VIII (BY-2 myosin VIII-1), and ER-localized green fluorescent protein vesicles. The ER tubules and their mesh-like structures were arranged in the S12 fraction efficiently by the addition of ATP, GTP, and exogenous filamentous actin. The tubule formation was significantly inhibited by the depletion of 175-kD myosin from the S12 fraction but not BY-2 myosin VIII-1. Furthermore, a recombinant carboxyl-terminal tail region of 175-kD myosin also suppressed ER tubule formation. The tips of tubules moved along filamentous actin during tubule elongation. These results indicated that the motive force generated by the actomyosin system contributes to the formation of ER tubules, suggesting that myosin XI is responsible not only for the transport of ER in cytoplasm but also for the reticular organization of cortical ER.

Solar Heating Systems with Evacuated Tubular Solar Collector

DEFF Research Database (Denmark)

Qin, Lin; Furbo, Simon

1998-01-01

Recently different designed evacuated tubular solar collectors were introduced on the market by different Chinese companies. In the present study, investigations on the performance of four different Chinese evacuated tubular collectors and of solar heating systems using these collectors were...... carried out, employing both laboratory test and theoretical calculations. The collectors were tested in a small solar domestic hot water (SDHW) system in a laboratory test facility under realistic conditions. The yearly thermal performance of solar heating systems with these evacuated tubular collectors......, as well as with normal flat-plate collectors was calculated under Danish weather conditions. It is found that, for small SDHW systems with a combi tank design, an increase of 25% -55% net utilized solar energy can be achieved by using these evacuated tubular collectors instead of normal flat...

GSTA3 Attenuates Renal Interstitial Fibrosis by Inhibiting TGF-Beta-Induced Tubular Epithelial-Mesenchymal Transition and Fibronectin Expression.

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Yun Xiao

Full Text Available Tubular epithelial-mesenchymal transition (EMT has been widely accepted as the underlying mechanisms of renal interstitial fibrosis (RIF. The production of reactive oxygen species (ROS plays a vital role in tubular EMT process. The purpose of this study was to investigate the involved molecular mechanisms in TGF-beta-induced EMT and identify the potential role of glutathione S-transferase alpha 3 (GSTA3 in this process. The iTRAQ screening was performed to identify protein alterations of the rats underwent unilateral-ureteral obstruction (UUO. Protein expression of GSTA3 in patients with obstructive nephropathy and UUO rats was detected by immunohistochemistry. Protein and mRNA expression of GSTA3 in UUO rats and NRK-52E cells were determined by Western blot and RT-PCR. siRNA and overexpression plasmid were transfected specifically to assess the role of GSTA3 in RIF. The generation of ROS was measured by dichlorofluorescein fluorescence analysis. GSTA3 protein and mRNA expression was significantly reduced in UUO rats. Immunohistochemical analysis revealed that GSTA3 expression was reduced in renal cortex in UUO rats and patients with obstructive nephropathy. Treating with TGF-β1 down-regulated GSTA3 expression in NRK-52E cells, which have been found to be correlated with the decreased expression in E-cadherin and megalin and increased expression in α-smooth muscle actin. Furthermore, knocking down GSTA3 in NRK-52 cells led to increased production of ROS and tubular EMT, whereas overexpressing GSTA3 ameliorated ROS production and prevented the occurrence of tubular EMT. GSTA3 plays a protective role against tubular EMT in renal fibrosis, suggesting GSTA3 is a potential therapeutic target for RIF.

Triple composite tumor of stomach: A rare combination of alpha fetoprotein positive hepatoid adenocarcinoma, tubular adenocarcinoma and large cell neuroendocrine carcinoma

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Lipika Lipi

2014-01-01

Full Text Available A 50-year-old male patient presented with pain abdomen of 6 months duration. Computed tomography scan revealed a large mass in the stomach occluding the lumen. Histopathology revealed a triple composite tumor comprising of tubular adenocarcinoma arising on a background of high-grade dysplasia, hepatoid adenocarcinoma (positive for Hep Par-1 and alpha fetoprotein and large cell neuroendocrine carcinoma (positive for synaptophysin and chromogranin with nodal metastasis.Triple composite tumors are distinctly rare with few reports in literature.

Tubular closure device

International Nuclear Information System (INIS)

Klahn, F.C.; Nolan, J.H.; Wills, C.

1982-01-01

This invention relates to a closure mechanism for closing openings such as the bore of a conduit and for releasably securing members within the bore. More particularly, this invention relates to a closure mechanism for tubular irradiation surveillance specimen assembly holders used in nuclear reactors

Acute tubular necrosis in a patient with paroxysmal nocturnal hemoglobinuria

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Eranga S Wijewickrama

2013-01-01

Full Text Available Acute renal failure (ARF is a well-recognized complication of paroxysmal nocturnal hemoglobinuria (PNH. The predominant mechanism is intravascular hemolysis resulting in massive hemoglobinuria ARF. We report a case of acute tubular necrosis (ATN developed in the absence of overwhelming evidence of intravascular hemolysis in a 21-year-old man with anemia, who was eventually diagnosed to have PNH. The patient presented with rapidly deteriorating renal functions in the background of iron deficiency anemia, which was attributed to reflux esophagitis. There was no clinical or laboratory evidence of intravascular hemolysis. Renal biopsy revealed ATN with deposition of hemosiderin in the proximal tubular epithelial cells. Diagnosis of PNH was confirmed with a positive Ham′s test and flow cytometry. Our case emphasizes the need to consider ATN as a possible cause for ARF in patients suspected to have PNH even in the absence of overwhelming evidence of intravascular hemolysis.

Renal cysteine conjugate C-S lyase mediated toxicity of halogenated alkenes in primary cultures of human and rat proximal tubular cells.

Science.gov (United States)

McGoldrick, Trevor A; Lock, Edward A; Rodilla, Vicente; Hawksworth, Gabrielle M

2003-07-01

Proximal tubular cells from human (HPT) and rat (RPT) kidneys were isolated, grown to confluence and incubated with S-(1,2-dichlorovinyl)- l-cysteine (DCVC), S-(1,2,2-trichlorovinyl)- l-cysteine (TCVC), S-(1,1,2,2-tetrafluoroethyl)- l-cysteine (TFEC) and S-(2-chloro-1,1-difluorethyl)- l-cysteine (CDFEC), the cysteine conjugates of nephrotoxicants. The cultures were exposed to the conjugates for 12, 24 and 48 h and the toxicity determined using the MTT assay. All four conjugates caused dose-dependent toxicity to RPT cells over the range 50-1,000 microM, the order of toxicity being DCVC>TCVC>TFEC=CDFEC. The inclusion of aminooxyacetic acid (AOAA; 250 microM), an inhibitor of pyridoxal phosphate-dependent enzymes such as C-S lyase, afforded protection, indicating that C-S lyase has a role in the bioactivation of these conjugates. In HPT cultures only DCVC caused significant time- and dose-dependent toxicity. Exposure to DCVC (500 microM) for 48 h decreased cell viability to 7% of control cell values, whereas co-incubation of DCVC (500 microM) with AOAA (250 microM) resulted in cell viability of 71%. Human cultures were also exposed to S-(1,2-dichlorovinyl)-glutathione (DCVG). DCVG was toxic to HPT cells, but the onset of toxicity was delayed compared with the corresponding cysteine conjugate. AOAA afforded almost complete protection from DCVG toxicity. Acivicin (250 microM), an inhibitor of gamma-glutamyl transferase (gamma-GT), partially protected against DCVG (500 microM)-induced toxicity at 48 h (5% viability and 53% viability in the absence and presence of acivicin, respectively). These results suggest that DCVG requires processing by gamma-GT prior to bioactivation by C-S lyase in HPT cells. The activity of C-S lyase, using TFEC as a substrate, and glutamine transaminase K (GTK) was measured in rat and human cells with time in culture. C-S lyase activity in RPT and HPT cells decreased to approximately 30% of fresh cell values by the time the cells reached

Hyperuricemia Induces Wnt5a/Ror2 Gene Expression, Epithelial–Mesenchymal Transition, and Kidney Tubular Injury in Mice

Directory of Open Access Journals (Sweden)

Wiwit Ananda Wahyu Setyaningsih

2018-03-01

Full Text Available Background: Hyperuricemia contributes to kidney injury, characterized by tubular injury with epithelial–mesenchymal transition (EMT. Wnt5a/Ror2 signaling drives EMT in many kidney pathologies. This study sought to evaluate the involvement of Wnt5a/Ror2 in hyperuricemia-induced EMT in kidney tubular injury. Methods: A hyperuricemia model was performed in male Swiss background mice (3 months old, 30–40 g with daily intraperitoneal injections of 125 mg/kg body weight (BW of uric acid. The mice were terminated on day 7 (UA7, n=5 and on day 14 (UA14, n=5. Allopurinol groups (UAl7 and UAl14, each n=5 were added with oral 50 mg/kg BW of allopurinol treatment. The serum uric acid level was quantified, and tubular injury was assessed based on PAS staining. Reverse transcriptase-PCR was done to quantify Wnt5a, Ror2, E-cadherin, and vimentin expressions. IHC staining was done for E-cadherin and collagen I. We used the Shapiro–Wilk for normality testing and one-way ANOVA for variance analysis with a P<0.05 as significance level using SPSS 22 software. Results: The hyperuricemia groups had a higher uric acid level, which was associated with a higher tubular injury score. Meanwhile, the allopurinol groups had a significantly lower uric acid level and tubular injury than the uric acid groups. Reverse transcriptase-PCR revealed downregulation of the E-cadherin expression. While vimentin and collagen I expression are upregulated, which was associated with a higher Wnt5a expression. However, the allopurinol groups had reverse results. Immunostaining revealed a reduction in E-cadherin staining in the epithelial cells and collagen I positive staining in the epithelial cells and the interstitial areas. Conclusion: Hyperuricemia induced tubular injury, which might have been mediated by EMT through the activation of Wnt5a.

Perfis tubulares : aspectos arquitetônicos e estruturais.

OpenAIRE

Gerken, Fernanda de Sousa

2003-01-01

Programa de Pós Graduação em Engenharia Civil. Departamento de Engenharia Civil, Escola de Minas, Universidade Federal de Ouro Preto. O presente trabalho tem como objetivo apresentar uma visão geral da utilização das estruturas tubulares no contexto da evolução das estruturas metálicas em geral, com destaque para o estudo de obras que mostram o estado da arte da construção tubular no Brasil. A utilização dos perfis tubulares estruturais é abordada tanto do ponto de vista da ...

Ranitidine has no influence on tubular creatinine secretion

NARCIS (Netherlands)

van den Berg, J. G.; Koopman, M. G.; Arisz, L.

1996-01-01

Oral cimetidine competitively inhibits tubular secretion of creatinine. We investigated the potential of oral ranitidine, a comparable H2-receptor antagonist, to block tubular creatinine secretion. In 10 healthy subjects, clearances of inulin and endogenous creatinine were simultaneously measured

[Decursin reduces reactive oxygen species and inhibits cisplatin-induced apoptosis in rat renal tubular epithelial cells].

Science.gov (United States)

Li, Cuiqiong; Li, Jianchun; Fan, Junming; Meng, Lifeng; Cao, Ling

2017-10-01

Objective To study the mechanism underlying the inhibitory effect of decursin on the apoptosis of rat renal tubular epithelial cells NRK-52E induced by cisplatin. Methods First, CCK-8 assay was used to detect the effects of 0, 10, 20, 40, 80, 100, 150, 200 μmol/L decursin and 0, 5, 10, 20, 30, 40, 50 μg/mL cispatin treatment for 24 hours on cell proliferation in NRK-52E cells via determining the half inhibitory concentration (IC 50 ). Then, NRK-52E cells were stimulated with 20 μg/mL cisplatin combined with 10, 50, 100 μmol/L decursin, and cell activity was detected by CCK-8 assay. The cells were divided into normal control group, 20 μg/mL cisplatin stimulation group, and 10, 50, 100 μmol/L decursin treated groups. Cell morphological changes was observed under inverted microscope, morphological changes of nucleus was detected by DAPI staining, cell apoptosis was detected by flow cytometry, the level of intracellular ROS was detected by DCFH-DA staining, and the apoptosis marker proteins cleaved-caspase-3 and cleaved-PARP were examined by Western blot analysis. Results Compared with the normal control group, cisplatin significantly inhibited the activity of the cells, and IC 50 was about 20 μg/mL; compared with the model group, in the decursin pretreatment groups, the level of intracellular ROS decreased remarkably, the expressions of cleaved-casspase-3 and cleaved-PARP proteins were reduced, and cell apoptosis was depressed. Conclusion Decursin can decrease the intracellular ROS level and inhibit the apoptosis of NRK-52E cells induced by cisplatin.

DEVELOPMENT OF TECHNICAL DECISIONS FOR HEAT SUPPLY WITH TUBULAR GAS HEATERS

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IRODOV V. F.

2017-05-01

Full Text Available Annotation. Problems formulation. The problem that is solved is the development of autonomous heat supply systems that reduce the capital costs of construction and increase the efficiency of the use of energy resources. One of the ways to solve this problem is the use of tubular gas heaters. For this, it is necessary to develop new technical solutions for heat supply with tubular gas heaters, as well as scientific and methodological support for the development, construction and operation of heat supply systems with tubular gas heaters. Analysis of recent research. Preliminary studies of infrared tubular gas heaters are considered, which were used to heat industrial enterprises with sufficiently high premises. The task was to extend the principles of heat supply by means of tubular heaters for heating air, water and heating medium in relatively low rooms. Goal and tasks. To lay out the development of technical solutions for heat supply with tubular gas heaters, which increase the efficiency and reliability of heat supply systems and extend the use of tubular gas heaters in heat supply. Results. Technical solutions for heat supply with tubular gas heaters have made it possible to extend their applications for heating air, water and heating medium in relatively low rooms. Scientific novelty. New technical solutions for heat supply with tubular gas heaters increase the efficiency of using fuel and energy resources at low capital costs. Practical significance. Technical solutions for heat supply using tubular heaters have the potential for wide application in the heat supply of industrial, public and residential facilities. Conclusions. For two decades, new technical solutions for heat supply with tubular gas heaters have been developed, which increase the efficiency and reliability of heat supply systems and can be widely used for autonomous heating.

Urinary excretion of beta 2-glycoprotein-1 (apolipoprotein H) and other markers of tubular malfunction in "non-tubular" renal disease.

Science.gov (United States)

Flynn, F V; Lapsley, M; Sansom, P A; Cohen, S L

1992-07-01

To determine whether urinary beta 2-glycoprotein-1 assays can provide improved discrimination between chronic renal diseases which are primarily of tubular or glomerular origin. Urinary beta 2-glycoprotein-1, retinol-binding protein, alpha 1-microglobulin, beta 2-microglobulin, N-acetyl-beta-D-glucosa-minidase and albumin were measured in 51 patients with primary glomerular disease, 23 with obstructive nephropathy, and 15 with polycystic kidney disease, and expressed per mmol of creatinine. Plasma beta 2-glycoprotein-1 was assayed in 52 patients and plasma creatinine in all 89. The findings were compared between the diagnostic groups and with previously published data relating to primary tubular disorders. All 31 patients with plasma creatinine greater than 200 mumol/l excreted increased amounts of beta 2-glycoprotein-1, retinol-binding protein, and alpha 1-microglobulin, and 29 had increased N-acetyl-beta-D-glucosaminidase; the quantities were generally similar to those found in comparable patients with primary tubular pathology. Among 58 with plasma creatinine concentrations under 200 mumol/l, increases in beta 2-glycoprotein-1, retinol-binding protein, and alpha 1-microglobulin excretion were less common and much smaller, especially in those with obstructive nephropathy and polycystic disease. The ratios of the excretion of albumin to the other proteins provided the clearest discrimination between the patients with glomerular or tubular malfunction, but an area of overlap was present which embraced those with obstructive nephropathy and polycystic disease. Increased excretion of beta 2-glycoprotein-1 due to a raised plasma concentration or diminution of tubular reabsorption, or both, is common in all the forms of renal disease investigated, and both plasma creatinine and urinary albumin must be taken into account when interpreting results. Ratios of urinary albumin: beta 2-glycoprotein-1 greater than 1000 are highly suggestive of primary glomerular disease and

Carbon dioxide reduction in a tubular solid oxide electrolysis cell for a carbon recycling energy system

Energy Technology Data Exchange (ETDEWEB)

Dipu, Arnoldus Lambertus, E-mail: dipu.a.aa@m.titech.ac.jp [Department of Nuclear Engineering, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo 152-8550 (Japan); Ujisawa, Yutaka [Nippon Steel and Sumitomo Metal Corporation, 16-1, Sunayama, Kamisu, Ibaraki 314-0255 (Japan); Ryu, Junichi; Kato, Yukitaka [Research Laboratory for Nuclear Reactors, Tokyo Institute of Technology, 2-12-1-N1-22, Ookayama, Meguro-ku, Tokyo 152-8550 (Japan)

2014-05-01

A new energy transformation system based on carbon recycling is proposed called the active carbon recycling energy system (ACRES). A high-temperature gas reactor was used as the main energy source for ACRES. An experimental study based on the ACRES concept of carbon monoxide (CO) regeneration via high-temperature reduction of carbon dioxide (CO{sub 2}) was carried out using a tubular solid oxide electrolysis cell employing Ni-LSM cermet|YSZ|YSZ-LSM as the cathode|electrolyte|anode. The current density increased with increasing CO{sub 2} concentration at the cathode, which was attributed to a decrease in cathode activation and concentration overpotential. Current density, as well as the CO and oxygen (O{sub 2}) production rates, increased with increasing operating temperature. The highest CO and O{sub 2} production rates of 1.24 and 0.64 μmol/min cm{sup 2}, respectively, were measured at 900 °C. Based on the electrolytic characteristics of the cell, the scale of a combined ACRES CO{sub 2} electrolysis/iron production facility was estimated.

BAG3 regulates ECM accumulation in renal proximal tubular cells induced by TGF-β1.

Science.gov (United States)

Du, Feng; Li, Si; Wang, Tian; Zhang, Hai-Yan; Li, De-Tian; Du, Zhen-Xian; Wang, Hua-Qin; Wang, Yan-Qiu

2015-01-01

Previously we have demonstrated that Bcl-2-associated athanogene 3 (BAG3) is increased in renal fibrosis using a rat unilateral ureteral obstruction model. The current study investigated the role of BAG3 in renal fibrosis using transforming growth factor (TGF)-β1-treated human proximal tubular epithelial (HK-2) cells. An upregulation of BAG3 in vitro models was observed, which correlated with the increased synthesis of extracellular matrix (ECM) proteins and expression of tissue-type plasminogen activator inhibitor (PAI)-1. Blockade of BAG3 induction by shorting hairpin RNA suppressed the expression of ECM proteins but had no effect on PAI-1 expression induced by TGF-β1. Forced overexpression of BAG3 selectively increased collagens. TGF-β1-induced BAG3 expression in HK-2 cells was attenuated by ERK1/2 and JNK MAPK inhibitors. In addition, forced BAG3 overexpression blocked attenuation of collagens expression by ERK1/2 and JNK inhibitors. These data suggest that ERK1/2 and JNK signaling events are involved in modulating the expression of BAG3, which would ultimately contribute to renal fibrosis by enhancing the synthesis and deposition of ECM proteins.

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium.

Science.gov (United States)

Smith, I M; Baker, A; Arneborg, N; Jespersen, L

2015-11-01

The human gastrointestinal epithelium makes up the largest barrier separating the body from the external environment. Whereas invasive pathogens cause epithelial barrier disruption, probiotic micro-organisms modulate tight junction regulation and improve epithelial barrier function. In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability of four nonpathogenic yeast species to modulate transepithelial electrical resistance (TER) across a monolayer of differentiated human colonocytes (Caco-2 cells). Further, we assessed yeast modulation of a Salmonella Typhimurium-induced epithelial cell barrier function insult. Our findings demonstrate distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study demonstrates distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Further, our data demonstrate significant yeast-mediated modulation of Salmonella Typhimurium-induced epithelial cell barrier disruption and identify Kluyveromyces marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. This study is the first to demonstrate significant non-Saccharomyces yeast

Recombination barrier layers in solid-state quantum dot-sensitized solar cells

KAUST Repository

Roelofs, Katherine E.

2012-06-01

By replacing the dye in the dye-sensitized solar cell design with semiconductor quantum dots as the light-absorbing material, solid-state quantum dot-sensitized solar cells (ss-QDSSCs) were fabricated. Cadmium sulfide quantum dots (QDs) were grown in situ by successive ion layer adsorption and reaction (SILAR). Aluminum oxide recombination barrier layers were deposited by atomic layer deposition (ALD) at the TiO2/hole-conductor interface. For low numbers of ALD cycles, the Al2O3 barrier layer increased open circuit voltage, causing an increase in device efficiency. For thicker Al2O3 barrier layers, photocurrent decreased substantially, leading to a decrease in device efficiency. © 2012 IEEE.

Laser Capture Microdissection and Multiplex-Tandem PCR Analysis of Proximal Tubular Epithelial Cell Signaling in Human Kidney Disease

Science.gov (United States)

Wilkinson, Ray; Wang, Xiangju; Kassianos, Andrew J.; Zuryn, Steven; Roper, Kathrein E.; Osborne, Andrew; Sampangi, Sandeep; Francis, Leo; Raghunath, Vishwas; Healy, Helen

2014-01-01

Interstitial fibrosis, a histological process common to many kidney diseases, is the precursor state to end stage kidney disease, a devastating and costly outcome for the patient and the health system. Fibrosis is historically associated with chronic kidney disease (CKD) but emerging evidence is now linking many forms of acute kidney disease (AKD) with the development of CKD. Indeed, we and others have observed at least some degree of fibrosis in up to 50% of clinically defined cases of AKD. Epithelial cells of the proximal tubule (PTEC) are central in the development of kidney interstitial fibrosis. We combine the novel techniques of laser capture microdissection and multiplex-tandem PCR to identify and quantitate “real time” gene transcription profiles of purified PTEC isolated from human kidney biopsies that describe signaling pathways associated with this pathological fibrotic process. Our results: (i) confirm previous in-vitro and animal model studies; kidney injury molecule-1 is up-regulated in patients with acute tubular injury, inflammation, neutrophil infiltration and a range of chronic disease diagnoses, (ii) provide data to inform treatment; complement component 3 expression correlates with inflammation and acute tubular injury, (iii) identify potential new biomarkers; proline 4-hydroxylase transcription is down-regulated and vimentin is up-regulated across kidney diseases, (iv) describe previously unrecognized feedback mechanisms within PTEC; Smad-3 is down-regulated in many kidney diseases suggesting a possible negative feedback loop for TGF-β in the disease state, whilst tight junction protein-1 is up-regulated in many kidney diseases, suggesting feedback interactions with vimentin expression. These data demonstrate that the combined techniques of laser capture microdissection and multiplex-tandem PCR have the power to study molecular signaling within single cell populations derived from clinically sourced tissue. PMID:24475278

Neuropilin-1 and neuropilin-2 are differentially expressed in human proteinuric nephropathies and cytokine-stimulated proximal tubular cells.

Science.gov (United States)

Schramek, Herbert; Sarközi, Rita; Lauterberg, Christina; Kronbichler, Andreas; Pirklbauer, Markus; Albrecht, Rudolf; Noppert, Susie-Jane; Perco, Paul; Rudnicki, Michael; Strutz, Frank M; Mayer, Gert

2009-11-01

Neuropilin-1 (NRP1) and neuropilin-2 (NRP2) are transmembrane glycoproteins with large extracellular domains that interact with class 3 semaphorins, vascular endothelial growth factor (VEGF) family members, and ligands, such as hepatocyte growth factor, platelet-derived growth factor BB, transforming growth factor-beta1 (TGF-beta1), and fibroblast growth factor2 (FGF2). Neuropilins (NRPs) have been implicated in tumor growth and vascularization, as novel mediators of the primary immune response and in regeneration and repair; however, their role in renal pathophysiology is largely unknown. Here, we report upregulation of tubular and interstitial NRP2 protein expression in patients with focal segmental glomerulosclerosis (FSGS). In an additional cohort of patients with minimal change disease (MCD), membranous nephropathy (MN), and FSGS, elevated NRP2 mRNA expression in kidney biopsies inversely correlated with estimated glomerular filtration rate (eGFR) at the time of biopsy. Furthermore, upregulation of NRP2 mRNA correlated with post-bioptic decline of kidney function. Expression of NRP1 and NRP2 in human proximal tubular cells (PTCs) was differentially affected after stimulation with TGF-beta1, interleukin-1beta (IL-1beta), and oncostatin M (OSM). Although the pro-fibrotic mediators, TGF-beta1 and IL-1beta, induced upregulation of NRP2 expression but downregulation of NRP1 expression, OSM stimulated the expression of both NRP1 and NRP2. Basal and OSM-induced NRP1 mRNA expression, as well as TGF-beta1-induced NRP2 mRNA and protein expression were partially mediated by MEK1/2-ERK1/2 signaling. This is the first report suggesting a differential role of NRP1 and NRP2 in renal fibrogenesis, and TGF-beta1, IL-1beta, and OSM represent the first ligands known to stimulate NRP2 expression in mammalian cells.

Functional characterization of apical transporters expressed in rat proximal tubular cells (PTCs) in primary culture.

Science.gov (United States)

Nakanishi, Takeo; Fukushi, Akimasa; Sato, Masanobu; Yoshifuji, Mayuko; Gose, Tomoka; Shirasaka, Yoshiyuki; Ohe, Kazuyo; Kobayashi, Masato; Kawai, Keiichi; Tamai, Ikumi

2011-12-05

Since in vitro cell culture models often show altered apical transporter expression, they are not necessarily suitable for the analysis of renal transport processes. Therefore, we aimed here to investigate the usefulness of primary-cultured rat proximal tubular cells (PTCs) for this purpose. After isolation of renal cortical cells from rat kidneys, PTCs were enriched and the gene expression and function of apical transporters were analyzed by means of microarray, RT-PCR and uptake experiments. RT-PCR confirmed that the major apical transporters were expressed in rat PTCs. Na(+)-dependent uptake of α-methyl-d-glucopyranoside (αMG), ergothioneine and carnitine by the PTCs suggests functional expression of Sglts, Octn1 and Octn2, respectively. Inhibition of pH-dependent glycylsarcosine uptake by low concentration of cephalexin, which is a β-lactam antibiotics recognized by Pepts, indicates a predominant role of high affinity type Pept2, but not low affinity type Pept1, in the PTCs. Moreover, the permeability ratio of [(14)C]αMG (apical to basolateral/basolateral to apical) across PTCs was 4.3, suggesting that Sglt-mediated reabsorptive transport is characterized. In conclusion, our results indicate that rat PTCs in primary culture are found to be a promising in vitro model to evaluate reabsorption processes mediated at least by Sglts, Pept2, Octn1 and Octn2.

Development and fabrication of a new concept planar-tubular solid oxide fuel cell (PT-SOFC)

Energy Technology Data Exchange (ETDEWEB)

Chen, Y.; Chen, F. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China); Department of Mechanical Engineering, University of South Carolina, 300 Main Street, Columbia, SC 29208 (United States); Ding, D. [School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332 (United States); Gao, J. [CAS Key Laboratory of Materials for Energy Conversion, Department of Materials Science and Engineering, University of Science and Technology of China, Hefei, 230026 Anhui (China)

2011-06-15

The paper reports a new concept of planar-tubular solid oxide fuel cell (PT-SOFC). Emphasis is on the fabrication of the required complex configuration of Ni-yttria-stabilised zirconia (YSZ) porous anode support by tert-butyl alcohol (TBA) based gelcasting, particularly the effects of solid loading, amounts of monomers and dispersant on the rheological behaviour of suspension, the shrinkage of a wet gelcast green body upon drying, and the properties of final sample after sintering at 1350 C and reduction from NiO-YSZ to Ni-YSZ. The results show that the gelcasting is a powerful method for preparation of the required complex configuration anode support. The anode support resulted from an optimised suspension with the solid loading of 25 vol% has uniform microstructure with 37% porosity, bending strength of 44 MPa and conductivity of 300 S cm{sup -} {sup 1} at 700 C, meeting the requirements for an anode support of SOFC. Based on the as-prepared anode support, PT-SOFC single cell of Ni-YSZ/YSZ/LSCF has been fabricated by slurry coating and co-sintering technique. The cell peak power density reaches 63, 106 and 141 mW cm {sup -} {sup 2} at 700, 750 and 800 C, respectively, using hydrogen as fuel and ambient air as oxidant. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Fabrication and characterization of anode-supported micro-tubular solide oxide fuel cell by phase inversion method

Science.gov (United States)

Ren, Cong

Nowadays, the micro-tubular solid oxide fuel cells (MT-SOFCs), especially the anode supported MT-SOFCs have been extensively developed to be applied for SOFC stacks designation, which can be potentially used for portable power sources and vehicle power supply. To prepare MT-SOFCs with high electrochemical performance, one of the main strategies is to optimize the microstructure of the anode support. Recently, a novel phase inversion method has been applied to prepare the anode support with a unique asymmetrical microstructure, which can improve the electrochemical performance of the MT-SOFCs. Since several process parameters of the phase inversion method can influence the pore formation mechanism and final microstructure, it is essential and necessary to systematically investigate the relationship between phase inversion process parameters and final microstructure of the anode supports. The objective of this study is aiming at correlating the process parameters and microstructure and further preparing MT-SOFCs with enhanced electrochemical performance. Non-solvent, which is used to trigger the phase separation process, can significantly influence the microstructure of the anode support fabricated by phase inversion method. To investigate the mechanism of non-solvent affecting the microstructure, water and ethanol/water mixture were selected for the NiO-YSZ anode supports fabrication. The presence of ethanol in non-solvent can inhibit the growth of the finger-like pores in the tubes. With the increasing of the ethanol concentration in the non-solvent, a relatively dense layer can be observed both in the outside and inside of the tubes. The mechanism of pores growth and morphology obtained by using non-solvent with high concentration ethanol was explained based on the inter-diffusivity between solvent and non-solvent. Solvent and non-solvent pair with larger Dm value is benefit for the growth of finger-like pores. Three cells with different anode geometries was

Management of oxidative stress by heme oxygenase-1 in cisplatin-induced toxicity in renal tubular cells.

Science.gov (United States)

Schaaf, G J; Maas, R F M; de Groene, E M; Fink-Gremmels, J

2002-08-01

Induction of heme oxygenase-1 (HO-1) may serve as an immediate protective response during treatment with the cytostatic drug cisplatin (CDDP). Oxidative pathways participate in the characteristic nephrotoxicity of CDDP. In the present study, cultured tubular cells (LLC-PK1) were used to investigate whether induction of HO provided protection against CDDP by maintaining the cellular redox balance. The antioxidants, alpha-tocopherol (TOCO) and N-acetylcysteine (NAC), were used to demonstrate that elevation of ROS levels contribute to the development of CDDP-induced cytotoxicity. Chemical modulators of HO activity were used to investigate the role of HO herein. Hemin was used to specifically induce HO-1, while exposure of the cells to tin-protoporphyrin (SnPP) was shown to inhibit HO activity. Hemin treatment prior to CDDP-exposure significantly decreased the generation of ROS to control levels, while inhibition of HO increased the ROS levels beyond the levels measured in cells treated with CDDP alone. Furthermore, HO induction protected significantly against the cytotoxicity of CDDP, although this protection was limited. Similar results were obtained when the cells were preincubated with TOCO, suggesting that mechanisms other than impairment of the redox ratio are important in CDDP-induced loss of cell viability in vitro. In addition, SnPP treatment exacerbated the oxidative response and cytotoxicity of CDDP, especially at low CDDP concentrations. We therefore conclude that HO is able to directly limit the CDDP-induced oxidative stress response and thus serves as safeguard of the cellular redox balance.

Role of mitochondrial permeability transition in human renal tubular epithelial cell death induced by aristolochic acid

International Nuclear Information System (INIS)

Qi Xinming; Cai Yan; Gong Likun; Liu Linlin; Chen Fangping; Xiao Ying; Wu Xiongfei; Li Yan; Xue Xiang; Ren Jin

2007-01-01

Aristolochic acid (AA), a natural nephrotoxin and carcinogen, can induce a progressive tubulointerstitial nephropathy. However, the mechanism by which AA causes renal injury remains largely unknown. Here we reported that the mitochondrial permeability transition (MPT) plays an important role in the renal injury induced by aristolochic acid I (AAI). We found that in the presence of Ca 2+ , AAI caused mitochondrial swelling, leakage of Ca 2+ , membrane depolarization, and release of cytochrome c in isolated kidney mitochondria. These alterations were suppressed by cyclosporin A (CsA), an agent known to inhibit MPT. Culture of HK-2 cell, a human renal tubular epithelial cell line for 24 h with AAI caused a decrease in cellular ATP, mitochondrial membrane depolarization, cytochrome c release, and increase of caspase 3 activity. These toxic effects of AAI were attenuated by CsA and bongkrekic acid (BA), another specific MPT inhibitor. Furthermore, AAI greatly inhibited the activity of mitochondrial adenine nucleotide translocator (ANT) in isolated mitochondria. We suggested that ANT may mediate, at least in part, the AAI-induced MPT. Taken together, these results suggested that MPT plays a critical role in the pathogenesis of HK-2 cell injury induced by AAI and implied that MPT might contribute to human nephrotoxicity of aristolochic acid

Reorganization of the Endosomal System in Salmonella-Infected Cells: The Ultrastructure of Salmonella-Induced Tubular Compartments

Science.gov (United States)

Krieger, Viktoria; Liebl, David; Zhang, Yuying; Rajashekar, Roopa; Chlanda, Petr; Giesker, Katrin; Chikkaballi, Deepak; Hensel, Michael

2014-01-01

During the intracellular life of Salmonella enterica, a unique membrane-bound compartment termed Salmonella-containing vacuole, or SCV, is formed. By means of translocated effector proteins, intracellular Salmonella also induce the formation of extensive, highly dynamic membrane tubules termed Salmonella-induced filaments or SIF. Here we report the first detailed ultrastructural analyses of the SCV and SIF by electron microscopy (EM), EM tomography and live cell correlative light and electron microscopy (CLEM). We found that a subset of SIF is composed of double membranes that enclose portions of host cell cytosol and cytoskeletal filaments within its inner lumen. Despite some morphological similarities, we found that the formation of SIF double membranes is independent from autophagy and requires the function of the effector proteins SseF and SseG. The lumen of SIF network is accessible to various types of endocytosed material and our CLEM analysis of double membrane SIF demonstrated that fluid phase markers accumulate only between the inner and outer membrane of these structures, a space continual with endosomal lumen. Our work reveals how manipulation of the endosomal membrane system by an intracellular pathogen results in a unique tubular membrane compartmentalization of the host cell, generating a shielded niche permissive for intracellular proliferation of Salmonella. PMID:25254663

Inner Surface Chirality of Single-Handed Twisted Carbonaceous Tubular Nanoribbons.

Science.gov (United States)

Liu, Dan; Li, Baozong; Guo, Yongmin; Li, Yi; Yang, Yonggang

2015-11-01

Single-handed twisted 4,4'-biphenylene-bridged polybissilsesquioxane tubular nanoribbons and single-layered nanoribbons were prepared by tuning the water/ethanol volume ratio in the reaction mixture at pH = 11.6 through a supramolecular templating approach. The single-layered nanoribbons were formed by shrinking tubular nanoribbons after the removal of the templates. In addition, solvent-induced handedness inversion was achieved. The handedness of the polybissilsesquioxanes could be controlled by changing the ethanol/water volume ratio in the reaction mixture. After carbonization at 900 °C for 4.0 h and removal of silica, single-handed twisted carbonaceous tubular nanoribbons and single-layered nanoribbons with micropores in the walls were obtained. X-ray diffraction and Raman spectroscopy analyses indicated that the carbon is predominantly amorphous. The circular dichroism spectra show that the twisted tubular nanoribbons exhibit optical activity, while the twisted single-layered nanoribbons do not. The results shown here indicate that chirality is transferred from the organic self-assemblies to the inner surfaces of the 4,4'-biphenylene-bridged polybissilsesquioxane tubular nanoribbons and subsequently to those of the carbonaceous tubular nanoribbons. © 2015 Wiley Periodicals, Inc.

Stearoyl-CoA Desaturase-1 Protects Cells against Lipotoxicity-Mediated Apoptosis in Proximal Tubular Cells

Directory of Open Access Journals (Sweden)

Tamaki Iwai

2016-11-01

Full Text Available Saturated fatty acid (SFA-related lipotoxicity is a pathogenesis of diabetes-related renal proximal tubular epithelial cell (PTEC damage, closely associated with a progressive decline in renal function. This study was designed to identify a free fatty acid (FFA metabolism-related enzyme that can protect PTECs from SFA-related lipotoxicity. Among several enzymes involved in FFA metabolism, we identified stearoyl-CoA desaturase-1 (SCD1, whose expression level significantly decreased in the kidneys of high-fat diet (HFD-induced diabetic mice, compared with non-diabetic mice. SCD1 is an enzyme that desaturates SFAs, converting them to monounsaturated fatty acids (MUFAs, leading to the formation of neutral lipid droplets. In culture, retrovirus-mediated overexpression of SCD1 or MUFA treatment significantly ameliorated SFA-induced apoptosis in PTECs by enhancing intracellular lipid droplet formation. In contrast, siRNA against SCD1 exacerbated the apoptosis. Both overexpression of SCD1 and MUFA treatment reduced SFA-induced apoptosis via reducing endoplasmic reticulum stress in cultured PTECs. Thus, HFD-induced decrease in renal SCD1 expression may play a pathogenic role in lipotoxicity-induced renal injury, and enhancing SCD1-mediated desaturation of SFA and subsequent formation of neutral lipid droplets may become a promising therapeutic target to reduce SFA-induced lipotoxicity. The present study provides a novel insight into lipotoxicity in the pathogenesis of diabetic nephropathy.

Barrier potential design criteria in multiple-quantum-well-based solar-cell structures

Science.gov (United States)

Mohaidat, Jihad M.; Shum, Kai; Wang, W. B.; Alfano, R. R.

1994-01-01

The barrier potential design criteria in multiple-quantum-well (MQW)-based solar-cell structures is reported for the purpose of achieving maximum efficiency. The time-dependent short-circuit current density at the collector side of various MQW solar-cell structures under resonant condition was numerically calculated using the time-dependent Schroedinger equation. The energy efficiency of solar cells based on the InAs/Ga(y)In(1-y)As and GaAs/Al(x)Ga(1-x)As MQW structues were compared when carriers are excited at a particular solar-energy band. Using InAs/Ga(y)In(1-y)As MQW structures it is found that a maximum energy efficiency can be achieved if the structure is designed with barrier potential of about 450 meV. The efficiency is found to decline linearly as the barrier potential increases for GaAs/Al(x)Ga(1-x)As MQW-structure-based solar cells.

Ni/Ni-YSZ current collector/anode dual layer hollow fibers for micro-tubular solid oxide fuel cells

Energy Technology Data Exchange (ETDEWEB)

Kanawka, K.; Othman, M.H.D.; Droushiotis, N.; Wu, Z.; Kelsall, G.; Li, K. [Department of Chemical Engineering and Chemical Technology, Imperial College London, London SW7 2AZ (United Kingdom)

2011-10-15

A co-extrusion technique was employed to fabricate a novel dual layer NiO/NiO-YSZ hollow fiber (HF) precursor which was then co-sintered at 1,400 C and reduced at 700 C to form, respectively, a meshed porous inner Ni current collector and outer Ni-YSZ anode layers for SOFC applications. The inner thin and highly porous ''mesh-like'' pure Ni layer of approximately 50 {mu}m in thickness functions as a current collector in micro-tubular solid oxide fuel cell (SOFC), aiming at highly efficient current collection with low fuel diffusion resistance, while the thicker outer Ni-YSZ layer of 260 {mu}m acts as an anode, providing also major mechanical strength to the dual-layer HF. Achieved morphology consisted of short finger-like voids originating from the inner lumen of the HF, and a sponge-like structure filling most of the Ni-YSZ anode layer, which is considered to be suitable macrostructure for anode SOFC system. The electrical conductivity of the meshed porous inner Ni layer is measured to be 77.5 x 10{sup 5} S m{sup -1}. This result is significantly higher than previous reported results on single layer Ni-YSZ HFs, which performs not only as a catalyst for the oxidation reaction, but also as a current collector. These results highlight the advantages of this novel dual-layer HF design as a new and highly efficient way of collecting current from the lumen of micro-tubular SOFC. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Fatigue Life of High-Strength Steel Offshore Tubular Joints

DEFF Research Database (Denmark)

Petersen, Rasmus Ingomar; Agerskov, Henning; Lopez Martinez, Luis

1996-01-01

In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high-strength......In the present investigation, the fatigue life of tubular joints in offshore steel structures is studied. Two test series on full-scale tubular joints have been carried through. One series was on joints in conventional offshore structural steel, and the other series was on joints in high......-strength steel with a yield stress of 820-830 MPa and with high weldability and toughness properties. The test specimens of both series had the same geometry. The present report concentrates on the results obtained in the investigation on the high-strength steel tubular joints.The test specimens were fabricated...... from Ø 324-610 mm tubes, and the joints were loaded in in-plane bending. Both fatigue tests under constant amplitude loading and tests with a stochastic loading that is realistic in relation to offshore structures, are included in the investigation.A comparison between constant amplitude and variable...

De novo expression of sodium-glucose cotransporter SGLT2 in Bowman’s capsule coincides with replacement of parietal epithelial cell layer with proximal tubule-like epithelium

OpenAIRE

Tabatabai, Niloofar M.; North, Paula E.; Regner, Kevin R.; Kumar, Suresh N.; Duris, Christine B.; Blodgett, Amy B.

2014-01-01

In kidney nephron, parietal epithelial cells line the Bowman’s capsule and function as a permeability barrier for the glomerular filtrate. Bowman’s capsule cells with proximal tubule epithelial morphology have been found. However, the effects of tubular metaplasia in Bowman’s capsule on kidney function remain poorly understood. Sodium-glucose cotransporter 2 (SGLT2) plays a major role in reabsorption of glucose in the kidney and is expressed on brush border membrane of epithelial cells in the...

Distal renal tubular acidosis and hepatic lipidosis in a cat.

Science.gov (United States)

Brown, S A; Spyridakis, L K; Crowell, W A

1986-11-15

Clinical and laboratory evidence of hepatic failure was found in a chronically anorectic cat. Simultaneous blood and urine pH determinations established a diagnosis of distal renal tubular acidosis. The cat did not respond to treatment. Necropsy revealed distal tubular nephrosis and hepatic lipidosis. The finding of distal renal tubular acidosis in a cat with hepatic lipidosis emphasizes the importance of complete evaluation of acid-base disorders in patients.

Transition piece for joining together tubular pieces

International Nuclear Information System (INIS)

Holko, K.H.

1981-01-01

A transition piece for joining together tubular pieces formed respectively from a low alloy or carbon steel and a high temperature alloy containing at least 16% chromium includes a plurality of tubular parts welded together and formed from materials of selected composition with a maximum chromium content difference of 5% between adjacent parts when the chromium content of each part is below 10% and a maximum chromium difference of 7% between adjacent parts when the chromium content of either part is above 10%. The transition parts are also graded as to such characteristics as thermal expansion coefficient. The transition parts at opposite ends of the transition joint have chromium percentages similar to the tubular pieces to which they are to be joined. The parts may be joined by fusion and/or friction welding and parts may be formed by fusion weld deposition. (author)

Modelling of alcohol fermentation in a tubular reactor with high biomass recycle

Energy Technology Data Exchange (ETDEWEB)

Narodoslawsky, M; Mittmannsgruber, H; Nagl, W; Moser, A

1988-05-30

Fermentation in tubular recycle reactors with high biomass concentrations is a way to boost productivity in alcohol production. A computer model has been developed to investigate the potential as well as to establish the limits of this process from a chemical engineering point of view. The model takes into account the kinetics of the reaction, the nonideality of flow and the segregation in the bioreactor. In accordance with literature, it is shown that tubular reactors with biomass recycle can improve productivity of alcohol fermentation substantially. With the help of the computer based reactor model it was also possible to estimate the detrimental effects of cell damage due to pumping. These effects are shown to play a major role, if the biomass separation is performed by filtration units which need high flow rates, e.g. tangential flow filters.

A neglected case of Renal Tubular Acidosis

International Nuclear Information System (INIS)

Derakhshan, A.; Basiratnia, M.; Fallahzadeh, M.H.; Al-Hashemi, G.H.

2007-01-01

In this report, we present a case of a child with distal renal tubular acidosis, severe failure to thrive and profound rickets, who was only 7.8 Kg when presented at 6 years of age. His response to treatment and his follow up for four years is discussed. Although failure to thrive is a common finding in renal tubular acidosis but the physical and x-ray findings in our case were unique. (author)

Involvement of endoplasmic reticulum stress in albuminuria induced inflammasome activation in renal proximal tubular cells.

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Li Fang

Full Text Available Albuminuria contributes to the progression of tubulointerstitial fibrosis. Although it has been demonstrated that ongoing albuminuria leads to tubular injury manifested by the overexpression of numerous proinflammatory cytokines, the mechanism remains largely unknown. In this study, we found that the inflammasome activation which has been recognized as one of the cornerstones of intracellular surveillance system was associated with the severity of albuminuria in the renal biopsies specimens. In vitro, bovine serum albumin (BSA could also induce the activation of NLRP3 inflammasome in the cultured kidney epithelial cells (NRK-52E. Since there was a significant overlap of NLRP3 with the ER marker calreticulin, the ER stress provoked by BSA seemed to play a crucial role in the activation of inflammasome. Here, we demonstrated that the chemical chaperone taurine-conjugated ursodeoxycholic acid (TUDCA which was proved to be an enhancer for the adaptive capacity of ER could attenuate the inflammasome activation induced by albuminuria not only in vitro but also in diabetic nephropathy. Taken together, these data suggested that ER stress seemed to play an important role in albuminuria-induced inflammasome activation, elimination of ER stress via TUDCA might hold promise as a novel avenue for preventing inflammasome activation ameliorating kidney epithelial cells injury induced by albuminuria.

Urotensin II Induces ER Stress and EMT and Increase Extracellular Matrix Production in Renal Tubular Epithelial Cell in Early Diabetic Mice

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Xin-Xin Pang

2016-07-01

Full Text Available Background/Aims: Urotensin II (UII and its receptor are highly expressed in the kidney tissue of patients with diabetic nephropathy (DN. The aim of this study is to examine the roles of UII in the induction of endoplasmic reticulum stress (ER stress and Epithelial-mesenchymal transition (EMT in DN in vivo and in vitro. Methods: Kidney tissues were collected from patients with DN. C57BL/6 mice and mice with UII receptor knock out were injected with two consecutive doses of streptozotocin to induce diabetes and were sacrificed at 3th week for in vivo study. HK-2 cells in vitro were cultured and treated with UII. Markers of ER stress and EMT, fibronectin and type IV collagen were detected by immunohistochemistry, real time PCR and western blot. Results: We found that the expressions of protein of UII, GRP78, CHOP, ALPHA-SMA, fibronectin and type IV collagen were upregulated while E-cadherin protein was downregulated as shown by immunohistochemistry or western blot analysis in kidney of diabetic mice in comparison to normal control; moreover expressions of GRP78, CHOP, ALPHA-SMA, fibronectin and type IV collagen were inhibited while E-caherin expression was enhanced in kidney in diabetic mice with UII receptor knock out in comparison to C57BL/6 diabetic mice. In HK-2 cells, UII induced upregulation of GRP78, CHOP, ALPHA-SMA, fibroblast-specifc protein 1(FSP-1, fibronectin and type collagen and downregulation of E-cadherin. UII receptor antagonist can block UII-induced ER stress and EMT; moreover, 4-PBA can inhibit the mRNA expression of ALPHA-SMA and FSP1 induced by UII in HK-2 cells. Conclusions: We are the first to verify UII induces ER stress and EMT and increase extracellular matrix production in renal tubular epithelial cell in early diabetic mice. Moreover, UII may induce renal tubular epithelial EMT via triggering ER stress pathway in vitro, which might be the new pathogenic pathway for the development of renal fibrosis in DN.

A young woman with recurrent kidney stones: questions on hypokalaemic tubular acidosis

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Jill Vanmassenhove

2017-04-01

Full Text Available This paper discusses the diagnostic and therapeutic approach to the problem of a young woman presenting with recurrent kidney stones. In the clinical work-up, a hypokalaemic normal anion gap metabolic acidosis was found. The diagnostic tests to solve this common clinical problem and some therapeutic recommendations are discussed. Question on hypokalaemic tubular acidosis: 1. What is the significance of the plasma anion gap (PAG? 2. How does one appreciate the respiratory component of the acid base status? 3. How does one perform tests for tubular acidification disturbances? 4. What is the pathogenesis of distal tubular acidification ­disturbances? 5. What is the explanation of the hypokalaemia in distal ­tubular acidosis? 6. What is the pathogenesis of nephrolithiasis in distal tubular acidosis? 7. How does one treat a patient with distal tubular acidosis and recurrent nephrolithiasis?

Contacting co-culture of human retinal microvascular endothelial cells alters barrier function of human embryonic stem cell derived retinal pigment epithelial cells.

Science.gov (United States)

Skottman, H; Muranen, J; Lähdekorpi, H; Pajula, E; Mäkelä, K; Koivusalo, L; Koistinen, A; Uusitalo, H; Kaarniranta, K; Juuti-Uusitalo, K

2017-10-01

Here we evaluated the effects of human retinal microvascular endothelial cells (hREC) on mature human embryonic stem cell (hESC) derived retinal pigment epithelial (RPE) cells. The hESC-RPE cells (Regea08/017, Regea08/023 or Regea11/013) and hREC (ACBRI 181) were co-cultured on opposite sides of transparent membranes for up to six weeks. Thereafter barrier function, small molecule permeability, localization of RPE and endothelial cell marker proteins, cellular fine structure, and growth factor secretion of were evaluated. After co-culture, the RPE specific CRALBP and endothelial cell specific von Willebrand factor were appropriately localized. In addition, the general morphology, pigmentation, and fine structure of hESC-RPE cells were unaffected. Co-culture increased the barrier function of hESC-RPE cells, detected both with TEER measurements and cumulative permeability of FD4 - although the differences varied among the cell lines. Co-culturing significantly altered VEGF and PEDF secretion, but again the differences were cell line specific. The results of this study showed that co-culture with hREC affects hESC-RPE functionality. In addition, co-culture revealed drastic cell line specific differences, most notably in growth factor secretion. This model has the potential to be used as an in vitro outer blood-retinal barrier model for drug permeability testing. Copyright © 2017 The Authors. Published by Elsevier Inc. All rights reserved.

Direct Reprogramming of Human Bone Marrow Stromal Cells into Functional Renal Cells Using Cell-free Extracts

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Evangelia Papadimou

2015-04-01

Full Text Available The application of cell-based therapies in regenerative medicine is gaining recognition. Here, we show that human bone marrow stromal cells (BMSCs, also known as bone-marrow-derived mesenchymal cells, can be reprogrammed into renal proximal tubular-like epithelial cells using cell-free extracts. Streptolysin-O-permeabilized BMSCs exposed to HK2-cell extracts underwent morphological changes—formation of “domes” and tubule-like structures—and acquired epithelial functional properties such as transepithelial-resistance, albumin-binding, and uptake and specific markers E-cadherin and aquaporin-1. Transmission electron microscopy revealed the presence of brush border microvilli and tight intercellular contacts. RNA sequencing showed tubular epithelial transcript abundance and revealed the upregulation of components of the EGFR pathway. Reprogrammed BMSCs integrated into self-forming kidney tissue and formed tubular structures. Reprogrammed BMSCs infused in immunodeficient mice with cisplatin-induced acute kidney injury engrafted into proximal tubuli, reduced renal injury and improved function. Thus, reprogrammed BMSCs are a promising cell resource for future cell therapy.

Tubular overexpression of gremlin induces renal damage susceptibility in mice.

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Alejandra Droguett

Full Text Available A growing number of patients are recognized worldwide to have chronic kidney disease. Glomerular and interstitial fibrosis are hallmarks of renal progression. However, fibrosis of the kidney remains an unresolved challenge, and its molecular mechanisms are still not fully understood. Gremlin is an embryogenic gene that has been shown to play a key role in nephrogenesis, and its expression is generally low in the normal adult kidney. However, gremlin expression is elevated in many human renal diseases, including diabetic nephropathy, pauci-immune glomerulonephritis and chronic allograft nephropathy. Several studies have proposed that gremlin may be involved in renal damage by acting as a downstream mediator of TGF-β. To examine the in vivo role of gremlin in kidney pathophysiology, we generated seven viable transgenic mouse lines expressing human gremlin (GREM1 specifically in renal proximal tubular epithelial cells under the control of an androgen-regulated promoter. These lines demonstrated 1.2- to 200-fold increased GREM1 expression. GREM1 transgenic mice presented a normal phenotype and were without proteinuria and renal function involvement. In response to the acute renal damage cause by folic acid nephrotoxicity, tubule-specific GREM1 transgenic mice developed increased proteinuria after 7 and 14 days compared with wild-type treated mice. At 14 days tubular lesions, such as dilatation, epithelium flattening and hyaline casts, with interstitial cell infiltration and mild fibrosis were significantly more prominent in transgenic mice than wild-type mice. Tubular GREM1 overexpression was correlated with the renal upregulation of profibrotic factors, such as TGF-β and αSMA, and with increased numbers of monocytes/macrophages and lymphocytes compared to wild-type mice. Taken together, our results suggest that GREM1-overexpressing mice have an increased susceptibility to renal damage, supporting the involvement of gremlin in renal damage

Confined diffusion in tubular structures analyzed by fluorescence correlation spectroscopy on a mirror

International Nuclear Information System (INIS)

Etienne, Emilien; Lenne, Pierre-Francois; Sturgis, James N.; Rigneault, Herve

2006-01-01

In fluorescence correlation spectroscopy (FCS) analysis it is generally assumed that molecular species diffuse freely in volumes much larger than the three-dimensional FCS observation volume. However, this standard assumption is not valid in many measurement conditions, particularly in tubular structures with diameters in the micrometer range, such as those found in living cells (organelles, dendrites) and microfluidic devices (capillaries,reaction chambers). As a result the measured autocorrelation functions (ACFs) deviate from those predicted for free diffusion, and this can shift the measured diffusion coefficient by as much as ∼50% when the tube diameter is comparable with the axial extension of the FCS observation volume. We show that the range of validity of the FCS measurements can be drastically improved if the tubular structures are located in the close vicinity of a mirror on which FCS is performed. In this case a new fluctuation time in the ACF, arising from the diffusion of fluorescent probes in optical fringes,permits measurement of the real diffusion coefficient within the tubular structure without assumptions about either the confined geometry orthe FCS observation volume geometry. We show that such a measurement can be done when the tubular structure contains at least one pair of dark and bright fringes resulting from interference between the incoming and the reflected excitation beams on the mirror surface. Measurement of the diffusion coefficient of the enhanced green fluorescent protein (EGFP) and IscS-EGFP in the cytoplasm of living Escherichiacoli illustrates the capabilities of the technique

New methods for the geometrical analysis of tubular organs.

Science.gov (United States)

Grélard, Florent; Baldacci, Fabien; Vialard, Anne; Domenger, Jean-Philippe

2017-12-01

This paper presents new methods to study the shape of tubular organs. Determining precise cross-sections is of major importance to perform geometrical measurements, such as diameter, wall-thickness estimation or area measurement. Our first contribution is a robust method to estimate orthogonal planes based on the Voronoi Covariance Measure. Our method is not relying on a curve-skeleton computation beforehand. This means our orthogonal plane estimator can be used either on the skeleton or on the volume. Another important step towards tubular organ characterization is achieved through curve-skeletonization, as skeletons allow to compare two tubular organs, and to perform virtual endoscopy. Our second contribution is dedicated to correcting common defects of the skeleton by new pruning and recentering methods. Finally, we propose a new method for curve-skeleton extraction. Various results are shown on different types of segmented tubular organs, such as neurons, airway-tree and blood vessels. Copyright © 2017 Elsevier B.V. All rights reserved.

Vibration analysis and sound field characteristics of a tubular ultrasonic radiator.

Science.gov (United States)

Liang, Zhaofeng; Zhou, Guangping; Zhang, Yihui; Li, Zhengzhong; Lin, Shuyu

2006-12-01

A sort of tubular ultrasonic radiator used in ultrasonic liquid processing is studied. The frequency equation of the tubular radiator is derived, and its radiated sound field in cylindrical reactor is calculated using finite element method and recorded by means of aluminum foil erosion. The results indicate that sound field of tubular ultrasonic radiator in cylindrical reactor appears standing waves along both its radial direction and axial direction, and amplitudes of standing waves decrease gradually along its radial direction, and the numbers of standing waves along its axial direction are equal to the axial wave numbers of tubular radiator. The experimental results are in good agreement with calculated results.

Ganoderma extract prevents albumin-induced oxidative damage and chemokines synthesis in cultured human proximal tubular epithelial cells.

Science.gov (United States)

Lai, Kar Neng; Chan, Loretta Y Y; Tang, Sydney C W; Leung, Joseph C K

2006-05-01

Ganoderma lucidum (Ganoderma or lingzhi) is widely used as an alternative medicine remedy to promote health and longevity. Recent studies have indicated that components extracted from Ganoderma have a wide range of pharmacological actions including suppressing inflammation and scavenging free radicals. We recently reported that tubular secretion of interleukin-8 (IL-8) induced by albumin is important in the pathogenesis of tubulointerstitial injury in the proteinuric state. In this study, we explored the protective effect of Ganoderma extract (LZ) on albumin-induced kidney epithelial injury. Growth arrested human proximal tubular epithelial cells (PTECs) were incubated with 0.625 to 10 mg/ml human serum albumin (HSA) for up to 72 h. HSA induced DNA damage and apoptosis in PTEC in a dose- and time-dependent manner. Co-incubation of PTEC with 4-64 microg/ml LZ significantly reduced the oxidative damage and cytotoxic effect of HSA in a dose-dependent manner (PGanoderma (16 microg/ml). To explore the components of LZ that exhibited most protective effect in HSA-induced PTEC damages, LZ was further separated into two sub-fractions, LZF1 (MW effective in reducing sICAM-1 released from HSA-activated PTEC whereas the high molecular weight LZ (unfractionated LZ) was more effective in diminishing IL-8 production. Our results suggest that Ganoderma significantly reduces oxidative damages and apoptosis in PTEC induced by HSA. The differential reduction of IL-8 or sICAM-1 released from HSA-activated PTEC by different components of the LZ implicates that components of Ganoderma with different molecular weights could play different roles and operate different mechanisms in preventing HSA-induced PTEC damage.

A microfluidic cell culture device with integrated microelectrodes for barrier studies

DEFF Research Database (Denmark)

Tan, Hsih-Yin; Dufva, Martin; Kutter, Jörg P.

We present an eight cell culture microfluidic device fabricated using thiol-ene ‘click’ chemistry with embedded microelectrodes for evaluating barrier properties of human intestinal epithelial cells. The capability of the microelectrodes for trans-epithelial electrical resistance (TEER) measureme......) measurements was demonstrated by using confluent human colorectal epithelial cells (Caco-2) and rat fibroblast (CT 26) cells cultured in the microfluidic device....

Mathematical modeling of methyl ester concentration distribution in a continuous membrane tubular reactor and comparison with conventional tubular reactor

Science.gov (United States)

Talaghat, M. R.; Jokar, S. M.; Modarres, E.

2017-10-01

The reduction of fossil fuel resources and environmental issues made researchers find alternative fuels include biodiesels. One of the most widely used methods for production of biodiesel on a commercial scale is transesterification method. In this work, the biodiesel production by a transesterification method was modeled. Sodium hydroxide was considered as a catalyst to produce biodiesel from canola oil and methanol in a continuous tubular ceramic membranes reactor. As the Biodiesel production reaction from triglycerides is an equilibrium reaction, the reaction rate constants depend on temperature and related linearly to catalyst concentration. By using the mass balance for a membrane tubular reactor and considering the variation of raw materials and products concentration with time, the set of governing equations were solved by numerical methods. The results clearly show the superiority of membrane reactor than conventional tubular reactors. Afterward, the influences of molar ratio of alcohol to oil, weight percentage of the catalyst, and residence time on the performance of biodiesel production reactor were investigated.

Generation of Urinary Albumin Fragments Does Not Require Proximal Tubular Uptake

OpenAIRE

Weyer, K.; Nielsen, R.; Christensen, E. I.; Birn, H.

2012-01-01

Urinary albumin excretion is an important diagnostic and prognostic marker of renal function. Both animal and human urine contain large amounts of albumin fragments, but whether these fragments originate from renal tubular degradation of filtered albumin is unknown. Here, we used mice with kidneys lacking megalin and cubilin, the coreceptors that mediate proximal tubular endocytosis of albumin, to determine whether proximal tubular degradation of albumin forms the detectable urinary albumin f...

Modeling constrained sintering of bi-layered tubular structures

DEFF Research Database (Denmark)

Tadesse Molla, Tesfaye; Kothanda Ramachandran, Dhavanesan; Ni, De Wei

2015-01-01

Constrained sintering of tubular bi-layered structures is being used in the development of various technologies. Densification mismatch between the layers making the tubular bi-layer can generate stresses, which may create processing defects. An analytical model is presented to describe the densi...... and thermo-mechanical analysis. Results from the analytical model are found to agree well with finite element simulations as well as measurements from sintering experiment....

A Cost-Effective Culture System for the In Vitro Assembly, Maturation, and Stimulation of Advanced Multilayered Multiculture Tubular Tissue Models.

Science.gov (United States)

Loy, Caroline; Pezzoli, Daniele; Candiani, Gabriele; Mantovani, Diego

2018-01-01

The development of tubular engineered tissues is a challenging research area aiming to provide tissue substitutes but also in vitro models to test drugs, medical devices, and even to study physiological and pathological processes. In this work, the design, fabrication, and validation of an original cost-effective tubular multilayered-tissue culture system (TMCS) are reported. By exploiting cellularized collagen gel as scaffold, a simple moulding technique and an endothelialization step on a rotating system, TMCS allowed to easily prepare in 48 h, trilayered arterial wall models with finely organized cellular composition and to mature them for 2 weeks without any need of manipulation. Multilayered constructs incorporating different combinations of vascular cells are compared in terms of cell organization and viscoelastic mechanical properties demonstrating that cells always progressively aligned parallel to the longitudinal direction. Also, fibroblast compacted less the collagen matrix and appeared crucial in term of maturation/deposition of elastic extracellular matrix. Preliminary studies under shear stress stimulation upon connection with a flow bioreactor are successfully conducted without damaging the endothelial monolayer. Altogether, the TMCS herein developed, thanks to its versatility and multiple functionalities, holds great promise for vascular tissue engineering applications, but also for other tubular tissues such as trachea or oesophagus. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Myosin XI-Dependent Formation of Tubular Structures from Endoplasmic Reticulum Isolated from Tobacco Cultured BY-2 Cells1[W][OA

Science.gov (United States)

Yokota, Etsuo; Ueda, Haruko; Hashimoto, Kohsuke; Orii, Hidefumi; Shimada, Tomoo; Hara-Nishimura, Ikuko; Shimmen, Teruo

2011-01-01

The reticular network of the endoplasmic reticulum (ER) consists of tubular and lamellar elements and is arranged in the cortical region of plant cells. This network constantly shows shape change and remodeling motion. Tubular ER structures were formed when GTP was added to the ER vesicles isolated from tobacco (Nicotiana tabacum) cultured BY-2 cells expressing ER-localized green fluorescent protein. The hydrolysis of GTP during ER tubule formation was higher than that under conditions in which ER tubule formation was not induced. Furthermore, a shearing force, such as the flow of liquid, was needed for the elongation/extension of the ER tubule. The shearing force was assumed to correspond to the force generated by the actomyosin system in vivo. To confirm this hypothesis, the S12 fraction was prepared, which contained both cytosol and microsome fractions, including two classes of myosins, XI (175-kD myosin) and VIII (BY-2 myosin VIII-1), and ER-localized green fluorescent protein vesicles. The ER tubules and their mesh-like structures were arranged in the S12 fraction efficiently by the addition of ATP, GTP, and exogenous filamentous actin. The tubule formation was significantly inhibited by the depletion of 175-kD myosin from the S12 fraction but not BY-2 myosin VIII-1. Furthermore, a recombinant carboxyl-terminal tail region of 175-kD myosin also suppressed ER tubule formation. The tips of tubules moved along filamentous actin during tubule elongation. These results indicated that the motive force generated by the actomyosin system contributes to the formation of ER tubules, suggesting that myosin XI is responsible not only for the transport of ER in cytoplasm but also for the reticular organization of cortical ER. PMID:21427277

Integrin-based diffusion barrier separates membrane domains enabling the formation of microbiostatic frustrated phagosomes

Science.gov (United States)

Maxson, Michelle E; Naj, Xenia; O'Meara, Teresa R; Plumb, Jonathan D; Cowen, Leah E

2018-01-01

Candida albicans hyphae can reach enormous lengths, precluding their internalization by phagocytes. Nevertheless, macrophages engulf a portion of the hypha, generating incompletely sealed tubular phagosomes. These frustrated phagosomes are stabilized by a thick cuff of F-actin that polymerizes in response to non-canonical activation of integrins by fungal glycan. Despite their continuity, the surface and invaginating phagosomal membranes retain a strikingly distinct lipid composition. PtdIns(4,5)P2 is present at the plasmalemma but is not detectable in the phagosomal membrane, while PtdIns(3)P and PtdIns(3,4,5)P3 co-exist in the phagosomes yet are absent from the surface membrane. Moreover, endo-lysosomal proteins are present only in the phagosomal membrane. Fluorescence recovery after photobleaching revealed the presence of a diffusion barrier that maintains the identity of the open tubular phagosome separate from the plasmalemma. Formation of this barrier depends on Syk, Pyk2/Fak and formin-dependent actin assembly. Antimicrobial mechanisms can thereby be deployed, limiting the growth of the hyphae. PMID:29553370

Urinary Markers of Tubular Injury in Early Diabetic Nephropathy

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Temesgen Fiseha

2016-01-01

Full Text Available Diabetic nephropathy (DN is a common and serious complication of diabetes associated with adverse outcomes of renal failure, cardiovascular disease, and premature mortality. Early and accurate identification of DN is therefore of critical importance to improve patient outcomes. Albuminuria, a marker of glomerular involvement in early renal damage, cannot always detect early DN. Thus, more sensitive and specific markers in addition to albuminuria are needed to predict the early onset and progression of DN. Tubular injury, as shown by the detection of tubular injury markers in the urine, is a critical component of the early course of DN. These urinary tubular markers may increase in diabetic patients, even before diagnosis of microalbuminuria representing early markers of normoalbuminuric DN. In this review we summarized some new and important urinary markers of tubular injury, such as neutrophil gelatinase associated lipocalin (NGAL, kidney injury molecule-1 (KIM-1, liver-type fatty acid binding protein (L-FABP, N-acetyl-beta-glucosaminidase (NAG, alpha-1 microglobulin (A1M, beta 2-microglobulin (B2-M, and retinol binding protein (RBP associated with early DN.

MODELING OF TUBULAR ELECTROCHEMICAL REACTOR FOR DYE REMOVAL

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V. VIJAYAKUMAR

2017-06-01

Full Text Available The aim of the present investigation is to model a tubular electrochemical reactor for the treatment of synthetic dye wastewater. The tubular reactor was modeled and solved by finite difference method. For the model solution, the column was divided into 11 nodes in the axial direction and the variation in the radial direction has been neglected. An initial dye concentration of 200 mg L-1was taken in the reservoir. The reactor was operated in a batch with recirculation operation. Based on preliminary experiments all parameters have been optimized. The model simulation is compared with the experimental value and it is observed that the model fairly matches well with the experiment. The modeling of tubular electrochemical reactors for dye waste water treatment could be useful in the design and scale up of electrochemical process.

Hyperactivation of Nrf2 in early tubular development induces nephrogenic diabetes insipidus

Science.gov (United States)

Suzuki, Takafumi; Seki, Shiori; Hiramoto, Keiichiro; Naganuma, Eriko; Kobayashi, Eri H.; Yamaoka, Ayaka; Baird, Liam; Takahashi, Nobuyuki; Sato, Hiroshi; Yamamoto, Masayuki

2017-01-01

NF-E2-related factor-2 (Nrf2) regulates cellular responses to oxidative and electrophilic stress. Loss of Keap1 increases Nrf2 protein levels, and Keap1-null mice die of oesophageal hyperkeratosis because of Nrf2 hyperactivation. Here we show that deletion of oesophageal Nrf2 in Keap1-null mice allows survival until adulthood, but the animals develop polyuria with low osmolality and bilateral hydronephrosis. This phenotype is caused by defects in water reabsorption that are the result of reduced aquaporin 2 levels in the kidney. Renal tubular deletion of Keap1 promotes nephrogenic diabetes insipidus features, confirming that Nrf2 activation in developing tubular cells causes a water reabsorption defect. These findings suggest that Nrf2 activity should be tightly controlled during development in order to maintain renal homeostasis. In addition, tissue-specific ablation of Nrf2 in Keap1-null mice might create useful animal models to uncover novel physiological functions of Nrf2. PMID:28233855

Gamma flux responsive self-powered detector with a tubular emitter

International Nuclear Information System (INIS)

Goldstein, N.P.; Todt, W.H.

1982-01-01

A gamma-sensitive flux detector comprises tubular emitter, an insulating core within the emitter and an insulating layer about the emitter, and a tubular conductive collector electrode about the insulating layer. The emitter material may be platinum, lead, bismuth, tantalum, tungsten; platinum preferred

Mathematical rationalization for the renal tubular transport: revised concepts.

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Mioni, Roberto; Marega, Alessandra; Romano, Giulio; Montanaro, Domenico

2017-09-01

The current emphasis on kinetics and in situ control of molecular exchanges, across the tubular membrane, has not been paralleled by corresponding improvements in our understanding of tubular behaviour at the macroscopic level of classical physiology. In this paper, we propose a mathematical rationalization of macroscopic tubular transport by means of a principal transport equation, originating from the law of mass action between substrate and carrier. The other equations, derived from the main one, demonstrate the possibility of distinguishing between transporters with low affinity and high capacity and transporters with high affinity and low capacity. Moreover, our model formalizes both tubular reabsorption and tubular secretion. Regarding the renal calcium handling, our model confirms the two-compartment system proposed by Mioni in 1971, with some important variants, which are in agreement with the fractional reabsorptions of this cation along the tubule, as verified by micro-puncture technique. To obtain the frequency distribution of saturated tubules, we have utilized the infinitesimal analysis method, starting from the equations proposed by Smith in 1943, concluding that all titration curves result from the combined effect of enzymatic approach and anatomical heterogeneity of the nephrons. The theoretical equations included in our manuscript reflect substantial and palpable physiological mechanisms able to suggest diagnosis and therapy of some electrolyte and hormonal disorders. At the end of this paper, we highlight advantages and disadvantages detectable by comparing our mathematical approach with Marshall's and Bijvoet's methods, proposed, respectively, in 1976 and 1984.

Live cell imaging techniques to study T cell trafficking across the blood-brain barrier in vitro and in vivo

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Coisne Caroline

2013-01-01

Full Text Available Abstract Background The central nervous system (CNS is an immunologically privileged site to which access for circulating immune cells is tightly controlled by the endothelial blood–brain barrier (BBB located in CNS microvessels. Under physiological conditions immune cell migration across the BBB is low. However, in neuroinflammatory diseases such as multiple sclerosis, many immune cells can cross the BBB and cause neurological symptoms. Extravasation of circulating immune cells is a multi-step process that is regulated by the sequential interaction of different adhesion and signaling molecules on the immune cells and on the endothelium. The specialized barrier characteristics of the BBB, therefore, imply the existence of unique mechanisms for immune cell migration across the BBB. Methods and design An in vitro mouse BBB model maintaining physiological barrier characteristics in a flow chamber and combined with high magnification live cell imaging, has been established. This model enables the molecular mechanisms involved in the multi-step extravasation of T cells across the in vitro BBB, to be defined with high-throughput analyses. Subsequently these mechanisms have been verified in vivo using a limited number of experimental animals and a spinal cord window surgical technique. The window enables live observation of the dynamic interaction between T cells and spinal cord microvessels under physiological and pathological conditions using real time epifluorescence intravital imaging. These in vitro and in vivo live cell imaging methods have shown that the BBB endothelium possesses unique and specialized mechanisms involved in the multi-step T cell migration across this endothelial barrier under physiological flow. The initial T cell interaction with the endothelium is either mediated by T cell capture or by T cell rolling. Arrest follows, and then T cells polarize and especially CD4+ T cells crawl over long distances against the direction of

Non-Saccharomyces yeasts protect against epithelial cell barrier disruption induced by Salmonella enterica subsp. enterica serovar Typhimurium

DEFF Research Database (Denmark)

Smith, Ida Mosbech; Baker, A; Arneborg, Nils

2015-01-01

distinct patterns of non-Saccharomyces yeast modulation of epithelial cell barrier function. While the established probiotic yeast Saccharomyces boulardii increased TER across a Caco-2 monolayer by 30%, Kluyveromyces marxianus exhibited significantly stronger properties of TER enhancement (50% TER increase....... In addition, probiotic strains may be able to reduce epithelial barrier disruption caused by pathogenic species. The aim of this study was to explore non-Saccharomyces yeast modulation of epithelial cell barrier function in vitro. Benchmarking against established probiotic strains, we evaluated the ability......). In addition, our data demonstrate significant yeast-mediated modulation of Salmonella-induced epithelial cell barrier disruption and identify K. marxianus and Metschnikowia gruessii as two non-Saccharomyces yeasts capable of protecting human epithelial cells from pathogen invasion. SIGNIFICANCE AND IMPACT...

pH measurement of tubular vacuoles of an arbuscular mycorrhizal fungus, Gigaspora margarita.

Science.gov (United States)

Funamoto, Rintaro; Saito, Katsuharu; Oyaizu, Hiroshi; Aono, Toshihiro; Saito, Masanori

2015-01-01

Arbuscular mycorrhizal fungi play an important role in phosphate supply to the host plants. The fungal hyphae contain tubular vacuoles where phosphate compounds such as polyphosphate are accumulated. Despite their importance for the phosphate storage, little is known about the physiological properties of the tubular vacuoles in arbuscular mycorrhizal fungi. As an indicator of the physiological state in vacuoles, we measured pH of tubular vacuoles in living hyphae of arbuscular mycorrhizal fungus Gigaspora margarita using ratio image analysis with pH-dependent fluorescent probe, 6-carboxyfluorescein. Fluorescent images of the fine tubular vacuoles were obtained using a laser scanning confocal microscope, which enabled calculation of vacuolar pH with high spatial resolution. The tubular vacuoles showed mean pH of 5.6 and a pH range of 5.1-6.3. These results suggest that the tubular vacuoles of arbuscular mycorrhizal fungi have a mildly acidic pH just like vacuoles of other fungal species including yeast and ectomycorrhizal fungi.

Mucinous tubular and spindle cell carcinoma of kidney: A clinicopathologic study of six cases

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Mudassar Hussain

2012-01-01

Full Text Available Background: Mucinous tubular and spindle carcinoma (MTSCC of kidney is a rare, low-grade polymorphic tumor. Recent studies have described a wide morphology spectrum of this tumor. Aim: To report the clinico-pathologic features of six cases of MTSCC of kidney. Materials and Methods: Six cases of MTSCC of kidney were studied and literature was reviewed. Immunohistochemistry was done by Envision method. Results: The age of the patients ranged from 44 to 84 years (mean 58.5 years. Four patients were males and two were females. The tumor was located in the left kidney in four cases and in the right kidney in two cases. The tumor size ranged from 4.5 to 15 cm (mean 6.4 cm. All tumors exhibited an admixture of tubules, spindle cells, and mucinous stroma in variable proportions. Tubules were predominant in five cases and spindle cells in one case. Psammomatous calcifications, papillations, and necrosis were seen in two cases. Collections of foamy histiocytes were noted in four cases. Cytoplasmic vacuoles and osseous metaplasia were seen in one case each. All cases were Fuhrman′s nuclear grade II. Five cases were of stage pT1, and one was pT3. All cases stained positive for alcian blue at pH 2.5. Immunohistochemical stain CK7 was positive in all cases and CD10 was positive in 1/1 case. All patients were alive and well at follow-up of 12-59 months (mean 33.5 months. No metastases were detected. Conclusions: We report six cases of MTSCC of kidney, a rare distinct variant of RCC, with a favorable prognosis. A male predominance was seen in our cases. MTSCC shares histologic and immunohistochemical overlap with papillary renal cell carcinoma (PRCC and cytogenetic analysis should be performed in difficult cases to avoid a misdiagnosis.

Preparation of platinum-free tubular dye-sensitized solar cells by electrophoretic deposition

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Khwanchit Wongcharee

2016-10-01

Full Text Available Tubular dye-sensitized solar cells (DSSCs were developed by replacing expensive materials with lower cost materials as follows: (1 replacing conductive glass electrodes with titanium (Ti wires and (2 replacing platinum (Pt catalyst with the mixture of multi-walled carbon nanotubes, MWCNTs and Poly(3,4-ethylenedioxythiophene-poly(styrenesulfonate, PEDOT-PSS. Platinized counter electrodes were used as the standard counter electrodes for comparison. The effects of the chemical treatment of titanium wire substrate and electrophoretic deposition condition on the efficiency of DSSCs were also investigated. The chemical treatment of titanium wires was carried out by soaking the wires in HF-HNO3 solutions at three different concentrations of 0.8, 1.6 and 2.4 M and three different soaking durations of 5, 10 and 15 min. The optimum condition was found at HF-HNO3 concentration of 0.8 M and soaking duration of 10 min. Film coating on working electrodes was performed using electrophoretic technique at three different voltages of 5, 8 and 10 V and four different coating durations of 1, 3, 5 and 7 min. Then, the optimum condition at deposition voltage of 5 V and deposition duration of 5 min was applied for film deposition on counter electrodes. The efficiency of DSSC with CNTs/TiO2 counter electrode was 0.03%. The addition of PEDOT-PSS improved the efficiency of DSSC to 0.08%.

Straw blood cell count, growth, inhibition and comparison to apoptotic bodies

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Tomkins Jeffrey P

2008-05-01

Full Text Available Abstract Background Mammalian cells transform into individual tubular straw cells naturally in tissues and in response to desiccation related stress in vitro. The transformation event is characterized by a dramatic cellular deformation process which includes: condensation of certain cellular materials into a much smaller tubular structure, synthesis of a tubular wall and growth of filamentous extensions. This study continues the characterization of straw cells in blood, as well as the mechanisms of tubular transformation in response to stress; with specific emphasis placed on investigating whether tubular transformation shares the same signaling pathway as apoptosis. Results There are approximately 100 billion, unconventional, tubular straw cells in human blood at any given time. The straw blood cell count (SBC is 45 million/ml, which accounts for 6.9% of the bloods dry weight. Straw cells originating from the lungs, liver and lymphocytes have varying nodules, hairiness and dimensions. Lipid profiling reveals severe disruption of the plasma membrane in CACO cells during transformation. The growth rates for the elongation of filaments and enlargement of rabbit straw cells is 0.6~1.1 (μm/hr and 3.8 (μm3/hr, respectively. Studies using apoptosis inhibitors and a tubular transformation inhibitor in CACO2 cells and in mice suggested apoptosis produced apoptotic bodies are mediated differently than tubular transformation produced straw cells. A single dose of 0.01 mg/kg/day of p38 MAPK inhibitor in wild type mice results in a 30% reduction in the SBC. In 9 domestic animals SBC appears to correlate inversely with an animal's average lifespan (R2 = 0.7. Conclusion Straw cells are observed residing in the mammalian blood with large quantities. Production of SBC appears to be constant for a given animal and may involve a stress-inducible protein kinase (P38 MAPK. Tubular transformation is a programmed cell survival process that diverges from apoptosis

Expansion of Tubular with Elastomers in Multilateral Wells

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Md Velden

2013-06-01

Full Text Available The use of solid expandable tubular technology during the last decade has focused on solving many challenges in well drilling and delivery including zonal isolation, deep drilling, conservation of hole sizes, etc. not only as pioneered solution but also providing cost effective and long lasting solutions. Concurrently, the technology was extended for construction of multilateral in typical wells. The process of horizontal tubular expansion is similar to the vertical expansion of expandable tubular in down-hole environment with the addition of uniformly distributed force due to its weight. The expansion is targeted to increase its diameter such that post expansion characteristics remain within allowable limits. In this study a typical expandable tubular of 57.15 mm outer diameter and 6.35 mm wall thickness was used with two different elastomer seals of 5 and 7 mm thickness placed at equal spacing of 200 mm. The developed stress contours during expansion process clearly showed the high stress areas in the vicinity of expansion region which lies around the mandrel. These high stresses may result in excessive wear of the mandrel. It was also found out that the drawing force increases as the mandrel angle, expansion ratio, and friction coefficient increases. A mandrel angle of 20o  requires minimum expansion force and can be considered as an optimum geometrical parameter to lower the power required for expansion.

Albumin stimulates renal tubular inflammation through an HSP70-TLR4 axis in mice with early diabetic nephropathy

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Jheng, Huei-Fen; Tsai, Pei-Jane; Chuang, Yi-Lun; Shen, Yi-Ting; Tai, Ting-An; Chen, Wen-Chung; Chou, Chuan-Kai; Ho, Li-Chun; Tang, Ming-Jer; Lai, Kuei-Tai A.; Sung, Junne-Ming; Tsai, Yau-Sheng

2015-01-01

ABSTRACT Increased urinary albumin excretion is not simply an aftermath of glomerular injury, but is also involved in the progression of diabetic nephropathy (DN). Whereas Toll-like receptors (TLRs) are incriminated in the renal inflammation of DN, whether and how albumin is involved in the TLR-related renal inflammatory response remains to be clarified. Here, we showed that both TLR2 and TLR4, one of their putative endogenous ligands [heat shock protein 70 (HSP70)] and nuclear factor-κB promoter activity were markedly elevated in the kidneys of diabetic mice. A deficiency of TLR4 but not of TLR2 alleviated albuminuria, tubulointerstitial fibrosis and inflammation induced by diabetes. The protection against renal injury in diabetic Tlr4−/− mice was associated with reduced tubular injuries and preserved cubilin levels, rather than amelioration of glomerular lesions. In vitro studies revealed that albumin, a stronger inducer than high glucose (HG), induced the release of HSP70 from proximal tubular cells. HSP70 blockade ameliorated albumin-induced inflammatory mediators. HSP70 triggered the production of inflammatory mediators in a TLR4-dependent manner. Moreover, HSP70 inhibition in vivo ameliorated diabetes-induced albuminuria, inflammatory response and tubular injury. Finally, we found that individuals with DN had higher levels of TLR4 and HSP70 in the dilated tubules than non-diabetic controls. Thus, activation of the HSP70-TLR4 axis, stimulated at least in part by albumin, in the tubular cell is a newly identified mechanism associated with induction of tubulointerstitial inflammation and aggravation of pre-existing microalbuminuria in the progression of DN. PMID:26398934

Toward improving mucosal barrier defenses: rhG-CSF plus IgG antibody.

Science.gov (United States)

Simmonds, Aryeh; LaGamma, Edmund F

2006-11-01

Epithelial cell functions ultimately define the ability of the extremely low birth weight human fetus to survive outside of the uterus. These specialized epithelial cell capacities manage all human interactions with the ex utero world including: (i) lung mechanics, surface chemistry and gas exchange, (ii) renal tubular balance of fluid and electrolytes, (iii) barrier functions of the intestine and skin for keeping bacteria out and water in, plus enabling intestinal digestion, as well as (iv) maintaining an intact neuroepithelium lining of the ventricles of the brain and retina. In Part I of this two part review, the authors describe why the gut barrier is a clinically relevant model system for studying the complex interplay between innate and adaptive immunity, dendritic &epithelial cell interactions, intraepithelial lymphocytes, M-cells, as well as the gut associated lymphoid tissues where colonization after birth, clinician feeding practices, use of antibiotics as well as exposure to prebiotics, probiotics and maternal vaginal flora all program the neonate for a life-time of immune competence distinguishing "self" from foreign antigens. These barrier defense capacities become destructive during disease processes like necrotizing enterocolitis (NEC) when an otherwise maturationally normal, yet dysregulated and immature, immune defense system is associated with high levels of certain inflammatory mediators like TNFa. In Part II the authors discuss the rationale for why rhG-CSF has theoretical advantages in managing NEC or sepsis by augmenting neonatal neutrophil number, neutrophil expression of Fcg and complement receptors, as well as phagocytic function and oxidative burst. rhG-CSF also has potent anti-TNFa functions that may serve to limit extension of tissue destruction while not impairing bacterial killing capacity. Healthy, non-infected neutropenic and septic neonates differ in their ability to respond to rhG-CSF; however, no neonatal clinical trials to date

Intrarenal purinergic signaling in the control of renal tubular transport

DEFF Research Database (Denmark)

Prætorius, Helle; Leipziger, Jens Georg

2010-01-01

-reaching advances indicate that ATP is often used as a local transmitter for classical sensory transduction. This transmission apparently also applies to sensory functions in the kidney. Locally released ATP is involved in sensing of renal tubular flow or in detecting the distal tubular load of NaCl at the macula...

Barrier effect of AlN film in flexible Cu(In,Ga)Se{sub 2} solar cells on stainless steel foil and solar cell

Energy Technology Data Exchange (ETDEWEB)

Li, Boyan; Li, Jianjun [Institute of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Wu, Li [The MOE Key Laboratory of Weak-Light Nonlinear Photonics, School of Physics, Nankai University, Tianjin 300071 (China); Liu, Wei; Sun, Yun [Institute of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China); Zhang, Yi, E-mail: yizhang@nankai.edu.cn [Institute of Photo-electronic Thin Film Devices and Technology, Key Laboratory of Photo-electronic Thin Film Devices and Technology of Tianjin, Nankai University, Tianjin 300071 (China)

2015-04-05

Highlights: • The adhension between AlN film and Mo are verygood. • AlN film can be effectively used as the barrier of flexible CIGS solar cell on SS substrate. • AlN film is suitable as the insulation barrier of flexible CIGS solar cell on SS substrate. - Abstract: The AlN film deposited by DC magnetron sputtering on stainless steel (SS) foils was used as the barrier in flexible Cu(In,Ga)Se{sub 2} (CIGS) solar cells on stainless steel foil and characterized comprehensively by X-ray diffraction (XRD), scanning electron microscopy (SEM), I–V, and QE measurements study. The study of AlN as insulation barrier in the flexible CIGS solar cell showed that the adhesion strength between the SS foil and the deposited AlN film was very strong even after annealing at high temperature at 530 °C. More importantly, a high resistance of over 10 MΩ was remained with the film with thickness of around 200 nm after annealing. This indicates that the AlN film is suitable as an effective insulation barrier in flexible CIGS solar cells based on SS foil. In addition, the XRD and SEM results showed that the AlN film did not influence the crystal structure of the Mo film which was deposited upon the AlN layer and used as the electrical contact in CIGS solar cells. It was found that the AlN film contributed to an improved crystallinity of the Mo contact layer compared to the bare SS foil. The combined results of secondary ion mass spectrometry, I–V and EQE measurements of the corresponding flexible CIGS solar cells confirmed that 1 μm-thick AlN film could be used as an efficient barrier layer in CIGS solar cells on SS foil.

Prevalence of renal tubular dysfunction in beta thalassemia minor in shiraz

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Ali Moradi Nakhodcheri

2012-02-01

Full Text Available  Background & objective: β-Thalassemia minor is an asymptomatic hereditary disease. The first study on the relation of renal tubular dysfunction and β-thalassemia minor was performed in 2002 but those studies seem inadequate.The main goal of this study is through evaluation of renal tubular function in 100 patients with thalassemia minor. Materials & Methods: 100 patients with β- thalassemia which confirmed by hemoglobin electrophoresis and CBC as well as RBC indices were studied.14 out of 100 cases exit because of Urinary Tract Infection, diabetes mellitus or hypertension.Complete chemistry profile was performed on serum and urine of all reminder 86 patients (46 female and 40 male. Patients classified into two groups: β-thalassemia minor with anemia and without anemia. Another control group include 50 healthy individuals also considered.Then data analyzed by proper statistical methods. Results: 20 out of 86 reminder cases e.g. 24% showed at least one index of renal tubular dysfunction.58% of patients was been anemic and 42% non anemic. The most prominent tubular dysfunction was seen in a 29 years old lady with glucosuria and without anemia. conclusion: β-Thalassemia minor is common in Iran specially in Fars province. This study revealed significant renal tubular dysfunction in patient with β-thalassemia minor. So it is necessary to check out thalassemic patients for renal function tests periodically. Key words: β-thalassemia, minor,renal tubular dysfunction

A tubular dielectric elastomer actuator: Fabrication, characterization and active vibration isolation

DEFF Research Database (Denmark)

Sarban, R.; Jones, R. W.; Mace, B. R.

2011-01-01

This contribution reviews the fabrication, characterization and active vibration isolation performance of a core-free rolled tubular dielectric elastomer (DE) actuator, which has been designed and developed by Danfoss PolyPower A/S. PolyPower DE material, PolyPower (TM), is produced in thin sheets...... of 80 mu m thickness with corrugated metallic electrodes on both sides. Tubular actuators are manufactured by rolling the DE sheets in a cylindrical shape. The electromechanical characteristics of such actuators are modeled based on equilibrium pressure equation. The model is validated with experimental...... the dominant dynamic characteristics of the core-free tubular actuator. It has been observed that all actuators have similar dynamic characteristics in a frequency range up to 1 kHz. A tubular actuator is then used to provide active vibration isolation (AVI) of a 250 g mass subject to shaker generated 'ground...

Toxicogenomic multigene biomarker for predicting the future onset of proximal tubular injury in rats

International Nuclear Information System (INIS)

Minowa, Yohsuke; Kondo, Chiaki; Uehara, Takeki; Morikawa, Yuji; Okuno, Yasushi; Nakatsu, Noriyuki; Ono, Atsushi; Maruyama, Toshiyuki; Kato, Ikuo; Yamate, Jyoji; Yamada, Hiroshi; Ohno, Yasuo; Urushidani, Tetsuro

2012-01-01

Drug-induced renal tubular injury is a major concern in the preclinical safety evaluation of drug candidates. Toxicogenomics is now a generally accepted tool for identifying chemicals with potential safety problems. The specific aim of the present study was to develop a model for use in predicting the future onset of drug-induced proximal tubular injury following repeated dosing with various nephrotoxicants. In total, 41 nephrotoxic and nonnephrotoxic compounds were used for the present analysis. Male Sprague-Dawley rats were dosed orally or intravenously once daily. Animals were exposed to three different doses (low, middle, and high) of each compound, and kidney tissue was collected at 3, 6, 9, and 24 h after single dosing, and on days 4, 8, 15, and 29 after repeated dosing. Gene expression profiles were generated from kidney total RNA using Affymetrix DNA microarrays. Filter-type gene selection and linear classification algorithms were employed to discriminate future onset of proximal tubular injury. We identified genomic biomarkers for use in future onset prediction using the gene expression profiles determined on day 1, when most of the nephrotoxicants had yet to produce detectable histopathological changes. The model was evaluated using a five-fold cross validation, and achieved a sensitivity of 93% and selectivity of 90% with 19 probes. We also found that the prediction accuracy of the optimized model was substantially higher than that produced by any of the single genomic biomarkers or histopathology. The genes included in our model were primarily involved in DNA replication, cell cycle control, apoptosis, and responses to oxidative stress and chemical stimuli. In summary, our toxicogenomic model is particularly useful for predicting the future onset of proximal tubular injury.

Review of the micro-tubular solid oxide fuel cell. Part I. Stack design issues and research activities

Energy Technology Data Exchange (ETDEWEB)

Lawlor, V. [Department of Eco-Energy Engineering, Upper Austrian University of Applied Sciences, A-4600 Wels (Austria); Department of Manufacturing and Mechanical Engineering, Dublin City University, Dublin 9 (Ireland); Griesser, S. [Department of Eco-Energy Engineering, Upper Austrian University of Applied Sciences, A-4600 Wels (Austria); Buchinger, G. [eZelleron GmbH, Collenbusch str. 22, 01324 Dresden (Germany); Olabi, A.G. [Department of Manufacturing and Mechanical Engineering, Dublin City University, Dublin 9 (Ireland); Cordiner, S. [Dipartimento di Ingegneria Meccanica - Universita di Roma Tor Vergata (Italy); Meissner, D. [Department of Eco-Energy Engineering, Upper Austrian University of Applied Sciences, A-4600 Wels (Austria); Department of Material Science, Tallinn University of Technology, Ehitajate 19086 (Estonia)

2009-09-05

Fuel cells are devices that convert chemical energy in hydrogen enriched fuels into electricity electrochemically. Micro-tubular solid oxide fuel cells (MT-SOFCs), the type pioneered by K. Kendall in the early 1990s, are a variety of SOFCs that are on the scale of millimetres compared to their much larger SOFC relatives that are typically on the scale of tens of centimetres. The main advantage of the MT-SOFC, over its larger predecessor, is that it is smaller in size and is more suitable for rapid start up. This may allow the SOFC to be used in devices such as auxiliary power units, automotive power supplies, mobile electricity generators and battery re-chargers. The following paper is Part I of a two part series. Part I will introduce the reader to the MT-SOFC stack and its applications, indicating who is researching what in this field and also specifically investigate the design issues related to multi-cell reactor systems called stacks. Part II will review in detail the combinations of materials and methods used to produce the electrodes and electrolytes of MT-SOFC's. Also the role of modelling and validation techniques used in the design and improvement of the electrodes and electrolytes will be investigated. A broad range of scientific and engineering disciplines are involved in a stack design. Scientific and engineering content has been discussed in the areas of thermal-self-sustainability and efficiency, sealing technologies, manifold design, electrical connections and cell performance optimisation. (author)

Meningeal mast cells affect early T cell central nervous system infiltration and blood-brain barrier integrity through TNF: a role for neutrophil recruitment?

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Sayed, Blayne A; Christy, Alison L; Walker, Margaret E; Brown, Melissa A

2010-06-15

Mast cells contribute to the pathogenesis of experimental autoimmune encephalomyelitis, a rodent model of the human demyelinating disease multiple sclerosis. Yet their site and mode of action is unknown. In both diseases, myelin-specific T cells are initially activated in peripheral lymphoid organs. However, for disease to occur, these cells must enter the immunologically privileged CNS through a breach in the relatively impermeable blood-brain barrier. In this study, we demonstrate that a dense population of resident mast cells in the meninges, structures surrounding the brain and spinal cord, regulate basal CNS barrier function, facilitating initial T cell CNS entry. Through the expression of TNF, mast cells recruit an early wave of neutrophils to the CNS. We propose that neutrophils in turn promote the blood-brain barrier breach and together with T cells lead to further inflammatory cell influx and myelin damage. These findings provide specific targets for intervention in multiple sclerosis as well as other immune-mediated CNS diseases.

Modified tubularized incised plate urethroplasty

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Shivaji Mane

2013-01-01

Full Text Available Aim: To share our experience of doing tubularized incised plate urethroplasty with modifications. Materials and Methods: This is a single surgeon personal series from 2004 to 2009. One hundred patients of distal hypospadias were subjected for Snodgrass urethroplasty with preputioplasty. The age range was 1 to 5 year with mean age of 2.7 years. Selection criteria were good urethral plate, without chordee and torsion needing complete degloving. Main technical modification from original Snodgrass procedure was spongioplasty, preputioplasty, and dorsal slit when inability to retract prepuce during surgery. Results: Average follow-up period is 23 months. Seven (7% patients developed fistula and one patient had complete preputial dehiscence. Phimosis developed in three (3% patients and required circumcision. Dorsal slit was required in seven patients. One patient developed meatal stenosis in postoperative period. All other patients are passing single urinary stream and have cosmesis that is acceptable. Conclusions: Modified tubularized incised plate urethroplasty with preputioplasty effectively gives cosmetically normal looking penis with low complications.

Solitary eccrine syringofibroadenoma: a case report showing papillary tubular adenoma-like features

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Toshiyuki Yamamoto

2016-10-01

Full Text Available We herein describe a case showing eccrine syringofibroadenoma occurred on the dorsum of the right foot of a 46-year-old Japanese female. Histopathologic examination revealed anastomosing cords and strands of cuboidal epithelial cells extending from the epidermis to the upper dermis, with a number of well-defined ducts suggesting eccrine ductal origin. In addition, there were papillary tubular adenoma-like ductal structures lined by a few rows of epithelial cells with papillary projections into the lumen surrounded by fibrous stroma in the mid-dermis. It is of note that various histologic features showing different differentiation were seen in a single lesion of eccrine syringofibroadenoma.

Modelling effects of current distributions on performance of micro-tubular hollow fibre solid oxide fuel cells

International Nuclear Information System (INIS)

Doraswami, U.; Droushiotis, N.; Kelsall, G.H.

2010-01-01

A three-dimensional model, considering mass, momentum, energy and charge conservation, was developed and the equations solved to describe the physico-chemical phenomena occurring within a single, micro-tubular hollow fibre solid oxide fuel cell (HF-SOFC). The model was used to investigate the spatial distributions of potential, current and reactants in a 10 mm long HF-SOFC. The predicted effects of location of current collectors, electrode conductivities, cathode thickness and porosity were analysed to minimise the ranges of current density distributions and maximise performance by judicious design. To decrease the computational load, azimuthal symmetry was assumed to model 50 and 100 mm long reactors in 2-D. With connectors at the same end of the HF-SOFC operating at a cell voltage of 0.5 V and a mean 5 kA m -2 , axial potential drops of ca. 0.14 V in the cathode were predicted, comparable to the cathode activation overpotential. Those potential drops caused average current densities to decrease from ca. 6.5 to ca.1 kA m -2 as HF-SOFC length increased from 10 to 100 mm, at which much of the length was inactive. Peak power densities were predicted to vary from 3.8 to -2 , depending on the location of the current collectors; performance increased with increasing cathode thickness and decreasing porosity.

Cadmium induces Ca2+ mediated, calpain-1/caspase-3-dependent apoptosis in primary cultured rat proximal tubular cells.

Science.gov (United States)

Wang, Hong; Zhai, Nianhui; Chen, Ying; Xu, Haibin; Huang, Kehe

2017-07-01

Calcium, as a ubiquitous second messenger, governs a large array of cellular processes and is necessary for cell survival. More recently, it was observed that the cytosolic Ca 2+ concentration ([Ca 2+ ] c ) elevation could induce apoptosis in primary cultured rat proximal tubular (rPT) cells exposed to cadmium (Cd), but the concrete mechanism is still unclear. This study was designed to investigate the signal pathway involved in [Ca 2+ ] c elevation-mediated apoptosis. The results confirmed the elevation of [Ca 2+ ] c by confocal microscopy and enhancement of the apoptosis by Hoechst 33258 staining and flow cytometer when rPT cells were exposed to Cd for 12h. Then we demonstrated that Cd enhanced the protein levels of active calpain-1 and caspase-3 in rPT cells. Pretreatment with a cytosolic Ca 2+ chelator, 1,2-Bis (2-aminophenoxy) ethane-N,N,N',N'-tetraacetic acid acetoxymethyl ester (BAPTA-AM), markedly blocked the up-regulation of active calpain-1 and caspase-3 and inhibited the apoptosis induced by Cd. Further, rPT cells were pretreated with a cell-permeable selective calpain-1 inhibitor, 3-(4-iodophenyl)-2-mercapto-(Z)-2-propenoic acid (PD150606) and caspase-3 inhibitor, N-Acetyl-Asp-Glu-Val-Asp-CHO (Ac-DEVD-CHO), respectively. PD150606 significantly attenuated the up-regulation of active caspase-3 and the apoptosis induced by Cd. As expected, inhibition of active caspase-3 by Ac-DEVD-CHO decreased the apoptosis induced by Cd. Taken together, it could be concluded that [Ca 2+ ] c elevation did act as a pro-apoptotic signal in Cd-induced cytotoxicity of rPT cells, triggered calpain-1 and caspase-3 activation in turn, and induced apoptosis of rPT cells. Copyright © 2017 Elsevier Inc. All rights reserved.

Diffusion chamber system for testing of collagen-based cell migration barriers for separation of ligament enthesis zones in tissue-engineered ACL constructs.

Science.gov (United States)

Hahner, J; Hoyer, M; Hillig, S; Schulze-Tanzil, G; Meyer, M; Schröpfer, M; Lohan, A; Garbe, L-A; Heinrich, G; Breier, A

2015-01-01

A temporary barrier separating scaffold zones seeded with different cell types prevents faster growing cells from overgrowing co-cultured cells within the same construct. This barrier should allow sufficient nutrient diffusion through the scaffold. The aim of this study was to test the effect of two variants of collagen-based barriers on macromolecule diffusion, viability, and the spreading efficiency of primary ligament cells on embroidered scaffolds. Two collagen barriers, a thread consisting of a twisted film tape and a sponge, were integrated into embroidered poly(lactic-co-caprolactone) and polypropylene scaffolds, which had the dimension of lapine anterior cruciate ligaments (ACL). A diffusion chamber system was designed and established to monitor nutrient diffusion using fluorescein isothiocyanate-labeled dextran of different molecular weights (20, 40, 150, 500 kDa). Vitality of primary lapine ACL cells was tested at days 7 and 14 after seeding using fluorescein diacetate and ethidium bromide staining. Cell spreading on the scaffold surface was measured using histomorphometry. Nuclei staining of the cross-sectioned scaffolds revealed the penetration of ligament cells through both barrier types. The diffusion chamber was suitable to characterize the diffusivity of dextran molecules through embroidered scaffolds with or without integrated collagen barriers. The diffusion coefficients were generally significantly lower in scaffolds with barriers compared to those without barriers. No significant differences between diffusion coefficients of both barrier types were detected. Both barriers were cyto-compatible and prevented most of the ACL cells from crossing the barrier, whereby the collagen thread was easier to handle and allowed a higher rate of cell spreading.

Biosensor Technology Reveals the Disruption of the Endothelial Barrier Function and the Subsequent Death of Blood Brain Barrier Endothelial Cells to Sodium Azide and Its Gaseous Products.

Science.gov (United States)

Kho, Dan T; Johnson, Rebecca H; O'Carroll, Simon J; Angel, Catherine E; Graham, E Scott

2017-09-21

Herein we demonstrate the sensitive nature of human blood-brain barrier (BBB) endothelial cells to sodium azide and its gaseous product. Sodium azide is known to be acutely cytotoxic at low millimolar concentrations, hence its use as a biological preservative (e.g., in antibodies). Loss of barrier integrity was noticed in experiments using Electric Cell-substrate Impedance Sensing (ECIS) biosensor technology, to measure endothelial barrier integrity continuously in real-time. Initially the effect of sodium azide was observed as an artefact where it was present in antibodies being employed in neutralisation experiments. This was confirmed where antibody clones that were azide-free did not mediate loss of barrier function. A delayed loss of barrier function in neighbouring wells implied the influence of a liberated gaseous product. ECIS technology demonstrated that the BBB endothelial cells had a lower level of direct sensitivity to sodium azide of ~3 µM. Evidence of gaseous toxicity was consistently observed at 30 µM and above, with disrupted barrier function and cell death in neighbouring wells. We highlight the ability of this cellular biosensor technology to reveal both the direct and gaseous toxicity mediated by sodium azide. The sensitivity and temporal dimension of ECIS technology was instrumental in these observations. These findings have substantial implications for the wide use of sodium azide in biological reagents, raising issues of their application in live-cell assays and with regard to the protection of the user. This research also has wider relevance highlighting the sensitivity of brain endothelial cells to a known mitochondrial disruptor. It is logical to hypothesise that BBB endothelial dysfunction due to mitochondrial dys-regulation could have an important but underappreciated role in a range of neurological diseases.

Macrophage-stimulating protein attenuates gentamicin-induced inflammation and apoptosis in human renal proximal tubular epithelial cells

Energy Technology Data Exchange (ETDEWEB)

Lee, Ko Eun [Department of Internal Medicine, Chonnam National University Medical School, Gwangju 501-757 (Korea, Republic of); Kim, Eun Young [Department of Physiology, Chonnam National University Medical School, Gwangju 501-757 (Korea, Republic of); Kim, Chang Seong; Choi, Joon Seok; Bae, Eun Hui; Ma, Seong Kwon [Department of Internal Medicine, Chonnam National University Medical School, Gwangju 501-757 (Korea, Republic of); Kim, Kyung Keun [Department of Pharmacology, Chonnam National University Medical School, Gwangju 501-757 (Korea, Republic of); Lee, Jong Un [Department of Physiology, Chonnam National University Medical School, Gwangju 501-757 (Korea, Republic of); Kim, Soo Wan, E-mail: skimw@chonnam.ac.kr [Department of Internal Medicine, Chonnam National University Medical School, Gwangju 501-757 (Korea, Republic of)

2013-05-10

Highlights: •MSP/RON system is activated in rat kidney damaged by gentamicin. •MSP inhibits GM-induced cellular apoptosis and inflammation in HK-2 cells. •MSP attenuates GM-induced activation of MAPKs and NF-κB pathways in HK-2 cells. -- Abstract: The present study aimed to investigate whether macrophage-stimulating protein (MSP) treatment attenuates renal apoptosis and inflammation in gentamicin (GM)-induced tubule injury and its underlying molecular mechanisms. To examine changes in MSP and its receptor, recepteur d’origine nantais (RON) in GM-induced nephropathy, rats were injected with GM for 7 days. Human renal proximal tubular epithelial (HK-2) cells were incubated with GM for 24 h in the presence of different concentrations of MSP and cell viability was measured by MTT assay. Apoptosis was determined by flow cytometry of cells stained with fluorescein isothiocyanate-conjugated annexin V protein and propidium iodide. Expression of Bcl-2, Bax, caspase-3, cyclooxygenase (COX)-2, inducible nitric oxide synthase (iNOS), nuclear factor-kappa B (NF-κB), IκB-α, and mitogen-activated protein kinases (MAPKs) was analyzed by semiquantitative immunoblotting. MSP and RON expression was significantly greater in GM-treated rats, than in untreated controls. GM-treatment reduced HK-2 cell viability, an effect that was counteracted by MSP. Flow cytometry and DAPI staining revealed GM-induced apoptosis was prevented by MSP. GM reduced expression of anti-apoptotic protein Bcl-2 and induced expression of Bax and cleaved caspase 3; these effects and GM-induced expression of COX-2 and iNOS were also attenuated by MSP. GM caused MSP-reversible induction of phospho-ERK, phospho-JNK, and phospho-p38. GM induced NF-κB activation and degradation of IκB-α; the increase in nuclear NF-κB was blocked by inhibitors of ERK, JNK, p-38, or MSP pretreatment. These findings suggest that MSP attenuates GM-induced inflammation and apoptosis by inhibition of the MAPKs

Cell-penetrating peptides for drug delivery across membrane barriers

DEFF Research Database (Denmark)

Foged, Camilla; Nielsen, Hanne Moerck

2008-01-01

During the last decade, cell-penetrating peptides have been investigated for their ability to overcome the plasma membrane barrier of mammalian cells for the intracellular or transcellular delivery of cargoes as diverse as low molecular weight drugs, imaging agents, oligonucleotides, peptides......, proteins and colloidal carriers such as liposomes and polymeric nanoparticles. Their ability to cross biological membranes in a non-disruptive way without apparent toxicity is highly desired for increasing drug bioavailability. This review provides an overview of the application of cell......-penetrating peptides as transmembrane drug delivery agents, according to the recent literature, and discusses critical issues and future challenges in relation to fully understanding the fundamental principles of the cell-penetrating peptide-mediated membrane translocation of cargoes and the exploitation...

Process for the fixing of a metallic end piece on a tubular component

International Nuclear Information System (INIS)

Charpin, Jean.

1975-01-01

Under this invention the process makes it possible to joint a tubular component and in particular a tubular filter and an end piece, with a connection of great mechanical strength, perfectly leak proof and with excellent corrosion resistance, particularly with respect to fluorinated by-products. This process is therefore of great worth in fixing to a bearer a thin ceramic compound tubular filter element, since such a filter can be used in particular for the separation of uranium isotopes by gaseous diffusion and for the separation of hydrocarbons in petrochemicals. To this end, the process under consideration is characterised in that it consists in depositing a layer of ceramic material, by hot projection, at the end of the tubular element and in sealing the end piece to the end of the tubular element by the hot projection of a ceramic or metallic substance [fr

In vitro precultivation alleviates post-implantation inflammation and enhances development of tissue-engineered tubular cartilage

Energy Technology Data Exchange (ETDEWEB)

Luo Xusong; Zhou Guangdong; Liu Wei; Zhang Wenjie; Cui Lei; Cao Yilin [Department of Plastic and Reconstructive Surgery, Shanghai Key Laboratory of Tissue Engineering, Shanghai 9th People' s Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200011 (China); Cen Lian, E-mail: guangdongzhou@126.co, E-mail: yilincao@yahoo.co [National Tissue Engineering Center of China, Shanghai 200011 (China)

2009-04-15

Tissue-engineered tubular cartilage is a promising graft for tracheal reconstruction. But polylactic acid/polyglycolic acid (PLA/PGA) fibers, the frequently used scaffolds for cartilage engineering, often elicit an obvious inflammation response following implantation into immunocompetent animals. We propose that the inflammation could be alleviated by in vitro precultivation. In this study, after in vitro culture for either 2 days (direct implantation group (DI)) or for 2 weeks (precultivation implantation group (PI)), autologous tubular chondrocyte-PLA/PGA constructs were subcutaneously implanted into rabbits. In the PI group, after 2 weeks of precultivation, most of the fibers were found to be completely embedded in an extracellular matrix (ECM) produced by the chondrocytes. Importantly, no obvious inflammatory reaction was observed after in vivo implantation and homogeneous cartilage-like tissue was formed with biomechanical properties close to native tracheal cartilage at 4 weeks post-implantation. In the DI group, however, an obvious inflammatory reaction was observed within and around the cell-scaffold constructs at 1 week implantation and only sporadic cartilage islands separated by fibrous tissue were observed at 4 weeks. These results demonstrated that the post-implantation inflammatory reaction could be alleviated by in vitro precultivation, which contributes to the formation of satisfactory tubular cartilage for tracheal reconstruction.

Interface Engineering of Organic Schottky Barrier Solar Cells and Its Application in Enhancing Performances of Planar Heterojunction Solar Cells

OpenAIRE

Fangming Jin; Zisheng Su; Bei Chu; Pengfei Cheng; Junbo Wang; Haifeng Zhao; Yuan Gao; Xingwu Yan; Wenlian Li

2016-01-01

In this work, we describe the performance of organic Schottky barrier solar cells with the structure of ITO/molybdenum oxide (MoOx)/boron subphthalocyanine chloride (SubPc)/bathophenanthroline (BPhen)/Al. The SubPc-based Schottky barrier solar cells exhibited a short-circuit current density (Jsc) of 2.59?mA/cm2, an open-circuit voltage (Voc) of 1.06?V, and a power conversion efficiency (PCE) of 0.82% under simulated AM1.5?G solar illumination at 100?mW/cm2. Device performance was substantiall...

Rectosigmoid tubular duplication presenting as perineal sepsis in a neonate.

Science.gov (United States)

Zhang, Zhibo; Huang, Ying; Wang, Dajia; Su, Pengjun

2010-03-01

Tubular rectal duplication is a very rare congenital anomaly. We report a case of tubular rectal duplication in a newborn baby who presented with perianal sepsis. The diagnosis was confirmed by barium enema, magnetic resonance imaging, and at operation. We performed total mucosectomy through a posterior sagittal incision combined with laparotomy. The patient was doing quite well at 17-month follow-up examination.

Boron--epoxy tubular structure members

Science.gov (United States)

Shakespeare, W. B. J.; Nelson, P. T.; Lindkvist, E. C.

1973-01-01

Composite materials fabricate thin-walled tubular members which have same load-carrying capabilities as aluminum, titanium, or other metals, but are lighter. Interface between stepped end fitting and tube lends itself to attachments by primary as well as secondary bonding. Interlaminar shear and hoop stress buildup in attachment at end fitting is avoided.

99mTc renal tubular function agents: Current status

International Nuclear Information System (INIS)

Eshima, D.; Fritzberg, A.R.; Taylor, A. Jr.

1990-01-01

Orthoiodohippuric (OIH) acid labeled with 131I is a widely used renal radiopharmaceutical agent and has been the standard radiopharmaceutical agent for the measurement of effective renal plasma flow (EPRF). Limitations to the routine clinical use of 131I OIH are related to the suboptimal imaging properties of the 131I radionuclide and its relatively high radiation dose. 123I has been substituted for 131I; however, its high cost and short shelf-life have limited its widespread use. Recent work has centered on the development of a new 99mTc renal tubular function agent, which would use the optimal radionuclidic properties and availability of 99mTc and combine the clinical information provided by OIH. The search for a suitable 99mTc renal tubular function agent has focused on the diamide dithiolate (N2S2), the paraaminohippuric iminodiacetic acid (PAHIDA), and the triamide mercaptide (N3S) donor ligand systems. To date, the most promising 99mTc tubular function agent is the N3S complex: 99mTc mercaptoacetyltriglycine (99mTc MAG3). Studies in animal models in diuresis, dehydration, acid or base imbalance, ischemia, and renal artery stenosis demonstrate that 99mTc MAG3 behaves similarly to 131I OIH. A simple kit formulation is available that yields the 99mTc MAG3 complex in high radiochemical purity. Studies in normal subjects and patients indicate that 99mTc MAG3 is an excellent 99mTc renal tubular agent, but its plasma clearance is only 50% to 60% that of OIH. In an effort to develop an improved 99mTc renal tubular function agent, changes have been made in the core N3S donor ligand system, but to date no agent has been synthesized that is clinically superior to 99mTc MAG3. 61 references

VALIDATION OF SIMULATION MODELS FOR DIFFERENTLY DESIGNED HEAT-PIPE EVACUATED TUBULAR COLLECTORS

DEFF Research Database (Denmark)

Fan, Jianhua; Dragsted, Janne; Furbo, Simon

2007-01-01

Differently designed heat-pipe evacuated tubular collectors have been investigated theoretically and experimentally. The theoretical work has included development of two TRNSYS [1] simulation models for heat-pipe evacuated tubular collectors utilizing solar radiation from all directions. One model...... coating on both sides. The input to the models is thus not a simple collector efficiency expression but the actual collector geometry. In this study, the TRNSYS models are validated with measurements for four differently designed heat-pipe evacuated tubular collectors. The collectors are produced...

Simultaneous cell death and desquamation of the embryonic diffusion barrier during epidermal development

International Nuclear Information System (INIS)

Saathoff, Manuela; Blum, Barbara; Quast, Thomas; Kirfel, Gregor; Herzog, Volker

2004-01-01

The periderm is an epithelial layer covering the emerging epidermis in early embryogenesis of vertebrates. In the chicken embryo, an additional cellular layer, the subperiderm, occurs at later embryonic stages underneath the periderm. The questions arose what is the function of both epithelial layers and, as they are transitory structures, by which mechanism are they removed. By immunocytochemistry, the tight junction (TJ) proteins occludin and claudin-1 were localized in the periderm and in the subperiderm, and sites of close contact between adjacent cells were detected by electron microscopy. Using horseradish peroxidase (HRP) as tracer, these contacts were identified as tight junctions involved in the formation of the embryonic diffusion barrier. This barrier was lost by desquamation at the end of the embryonic period, when the cornified envelope of the emerging epidermis was formed. By TUNEL and DNA ladder assays, we detected simultaneous cell death in the periderm and the subperiderm shortly before hatching. The absence of caspases-3, -6, and -7 activity, key enzymes of apoptosis, and the lack of typical morphological criteria of apoptosis such as cell fragmentation or membrane blebbing point to a special form of programmed cell death (PCD) leading to the desquamation of the embryonic diffusion barrier

Barriers to Mental Health Service Use among Hematopoietic Stem Cell Transplant Survivors

OpenAIRE

Mosher, Catherine E.; DuHamel, Katherine N.; Rini, Christine M.; Li, Yuelin; Isola, Luis; Labay, Larissa; Rowley, Scott; Papadopoulos, Esperanza; Moskowitz, Craig; Scigliano, Eileen; Grosskreutz, Celia; Redd, William H.

2009-01-01

Summary This study examined barriers to mental health service use and their demographic, medical, and psychosocial correlates among hematopoietic stem cell transplant (HSCT) survivors. A sample of 253 HSCT survivors who were 1- to 3-years post-transplant completed measures of demographic, physical, psychological, and social characteristics as well as a newly modified measure of barriers to mental health service use. Only 50% of distressed HSCT survivors had received mental health services. An...

Genome-wide analysis of murine renal distal convoluted tubular cells for the target genes of mineralocorticoid receptor

Energy Technology Data Exchange (ETDEWEB)

Ueda, Kohei [Department of Nephrology and Endocrinology, The University of Tokyo, Tokyo (Japan); Fujiki, Katsunori; Shirahige, Katsuhiko [Research Center for Epigenetic Disease, Institute of Molecular and Cellular Biosciences, The University of Tokyo, Tokyo (Japan); Gomez-Sanchez, Celso E. [Endocrine Section, G.V. (Sonny) Montgomery VA Medical Center, MS (United States); Endocrinology, University of Mississippi Medical Center, MS (United States); Fujita, Toshiro [Division of Clinical Epigenetics, Research Center for Advanced Science and Technology, The University of Tokyo, Tokyo (Japan); Nangaku, Masaomi [Department of Nephrology and Endocrinology, The University of Tokyo, Tokyo (Japan); Nagase, Miki, E-mail: mnagase-tky@umin.ac.jp [Department of Nephrology and Endocrinology, The University of Tokyo, Tokyo (Japan); Department of Anatomy and Life Structure, School of Medicine Juntendo University, Tokyo (Japan)

2014-02-28

Highlights: • We define a target gene of MR as that with MR-binding to the adjacent region of DNA. • We use ChIP-seq analysis in combination with microarray. • We, for the first time, explore the genome-wide binding profile of MR. • We reveal 5 genes as the direct target genes of MR in the renal epithelial cell-line. - Abstract: Background and objective: Mineralocorticoid receptor (MR) is a member of nuclear receptor family proteins and contributes to fluid homeostasis in the kidney. Although aldosterone-MR pathway induces several gene expressions in the kidney, it is often unclear whether the gene expressions are accompanied by direct regulations of MR through its binding to the regulatory region of each gene. The purpose of this study is to identify the direct target genes of MR in a murine distal convoluted tubular epithelial cell-line (mDCT). Methods: We analyzed the DNA samples of mDCT cells overexpressing 3xFLAG-hMR after treatment with 10{sup −7} M aldosterone for 1 h by chromatin immunoprecipitation with deep-sequence (ChIP-seq) and mRNA of the cell-line with treatment of 10{sup −7} M aldosterone for 3 h by microarray. Results: 3xFLAG-hMR overexpressed in mDCT cells accumulated in the nucleus in response to 10{sup −9} M aldosterone. Twenty-five genes were indicated as the candidate target genes of MR by ChIP-seq and microarray analyses. Five genes, Sgk1, Fkbp5, Rasl12, Tns1 and Tsc22d3 (Gilz), were validated as the direct target genes of MR by quantitative RT-qPCR and ChIP-qPCR. MR binding regions adjacent to Ctgf and Serpine1 were also validated. Conclusions: We, for the first time, captured the genome-wide distribution of MR in mDCT cells and, furthermore, identified five MR target genes in the cell-line. These results will contribute to further studies on the mechanisms of kidney diseases.

Micro-Drilling of Polymer Tubular Ultramicroelectrode Arrays for Electrochemical Sensors

Directory of Open Access Journals (Sweden)

Niels B. Larsen

2013-05-01

Full Text Available We present a reproducible fast prototyping procedure based on micro-drilling to produce homogeneous tubular ultramicroelectrode arrays made from poly(3,4-ethylenedioxythiophene (PEDOT, a conductive polymer. Arrays of Ø 100 µm tubular electrodes each having a height of 0.37 ± 0.06 µm were reproducibly fabricated. The electrode dimensions were analyzed by SEM after deposition of silver dendrites to visualize the electroactive electrode area. The electrochemical applicability of the electrodes was demonstrated by voltammetric and amperometric detection of ferri-/ferrocyanide. Recorded signals were in agreement with results from finite element modelling of the system. The tubular PEDOT ultramicroelectrode arrays were modified by prussian blue to enable the detection of hydrogen peroxide. A linear sensor response was demonstrated for hydrogen peroxide concentrations from 0.1 mM to 1 mM.

Tubular transport and metabolism of cimetidine in chicken kidneys

International Nuclear Information System (INIS)

Rennick, B.; Ziemniak, J.; Smith, I.; Taylor, M.; Acara, M.

1984-01-01

Renal tubular transport and renal metabolism of [ 14 C]cimetidine (CIM) were investigated by unilateral infusion into the renal portal circulation in chickens (Sperber technique). [ 14 C]CIM was actively transported at a rate 88% that of simultaneously infused p-aminohippuric acid, and its transport was saturable. The following organic cations competitively inhibited the tubular transport of [ 14 C]CIM with decreasing potency: CIM, ranitidine, thiamine, procainamide, guanidine and choline. CIM inhibited the transport of [ 14 C]thiamine, [ 14 C]amiloride and [ 14 C]tetraethylammonium. During CIM infusion, two renal metabolites, CIM sulfoxide and hydroxymethylcimetidine, were found in urine. When CIM sulfoxide was infused, its transport efficiency was 32% and not saturable. CIM sulfoxide did ot inhibit the simultaneous renal tubular transport of p-aminohippuric acid or tetraethylammonium. CIM is transported by the organic cation transport system and the kidney metabolizes CIM. Transport of CIM and other cationic drugs could produce a drug interaction to alter drug excretion

HER-2 amplification in tubular carcinoma of the breast.

Science.gov (United States)

Oakley, Gerard J; Tubbs, Raymond R; Crowe, Joseph; Sebek, Bruce; Budd, G Thomas; Patrick, Rebecca J; Procop, Gary W

2006-07-01

The prognostic and therapeutic implications of HER-2 gene amplification and estrogen and progesterone receptor status in breast cancer are well described. To address the relative paucity of information concerning HER-2 amplification for tubular carcinomas, we assessed the frequency of gene amplification in 55 tubular carcinomas of the breast from 54 patients, 5 of which had axillary node metastases. The HER-2 gene copy number was assessed by fluorescence in situ hybridization for the majority of tumors analyzed, whereas estrogen and progesterone receptor status was achieved by immunohistochemical analysis. HER-2 gene amplification was not observed in any of the tumors examined, and most were estrogen receptor-positive. This HER-2 gene amplification frequency was significantly lower than the frequency of gene amplification previously reported for all invasive ductal carcinoma of no special type (P < .01). HER-2 gene amplification likely occurs infrequently, or not at all, in tubular carcinomas of the breast, whereas most express estrogen receptors.

Work tool in a tubular element

International Nuclear Information System (INIS)

Griffaton, J.

1991-01-01

The stand, which is positioned in relation with the tubular element, has clutch disengagement means for a working rod in rotation, with at least two positioning regions on the rod. Application for laser welding a sleeve into PWR steam generator tubes [fr

Renal Tubular Function in Systemic Lupus Erythematosus*

African Journals Online (AJOL)

immune' diseases such as. Sjogren's syndrome,'" systemic lupus erythematosus. (SLE),3 alveolitis' and chronic active hepatitis.' The reported abnormalities of renal tubular function include impairment of acid excretion and urinary concentration.

Autophagy Limits Endotoxemic Acute Kidney Injury and Alters Renal Tubular Epithelial Cell Cytokine Expression.

Directory of Open Access Journals (Sweden)

Jeremy S Leventhal

Full Text Available Sepsis related acute kidney injury (AKI is a common in-hospital complication with a dismal prognosis. Our incomplete understanding of disease pathogenesis has prevented the identification of hypothesis-driven preventive or therapeutic interventions. Increasing evidence in ischemia-reperfusion and nephrotoxic mouse models of AKI support the theory that autophagy protects renal tubular epithelial cells (RTEC from injury. However, the role of RTEC autophagy in septic AKI remains unclear. We observed that lipopolysaccharide (LPS, a mediator of gram-negative bacterial sepsis, induces RTEC autophagy in vivo and in vitro through TLR4-initiated signaling. We modeled septic AKI through intraperitoneal LPS injection in mice in which autophagy-related protein 7 was specifically knocked out in the renal proximal tubules (ATG7KO. Compared to control littermates, ATG7KO mice developed more severe renal dysfunction (24hr BUN 100.1mg/dl +/- 14.8 vs 54.6mg/dl +/- 11.3 and parenchymal injury. After injection with LPS, analysis of kidney lysates identified higher IL-6 expression and increased STAT3 activation in kidney lysates from ATG7KO mice compared to controls. In vitro experiments confirmed an altered response to LPS in RTEC with genetic or pharmacological impairment of autophagy. In conclusion, RTEC autophagy protects against endotoxin induced injury and regulates downstream effects of RTEC TLR4 signaling.

CT and MR imaging features of mucinous tubular and spindle cell carcinoma of the kidneys. A multi-institutional review

Energy Technology Data Exchange (ETDEWEB)

Cornelis, F.; Grenier, N. [Pellegrin Hospital, Department of Radiology, Bordeaux (France); Ambrosetti, D. [Pasteur Hospital, Department of Pathology, Nice (France); Rocher, L. [Kremlin-Bicetre Hospital, Department of Radiology, Paris (France); Derchi, L.E. [University of Genoa, IRCCS AOU Ospedale, San Martino IST, Department of Health Sciences (DISSAL), Genoa (Italy); Renard, B.; Puech, P. [Claude Huriez Hospital, Department of Radiology, Lille (France); Claudon, M. [Brabois Hospital, Department of Radiology, Vandoeuvre-les-Nancy (France); Rouviere, O. [E. Herriot Hospital, Department of Radiology, Lyon (France); Ferlicot, S. [Kremlin-Bicetre Hospital, Department of Pathology, Paris (France); Roy, C. [Civil Hospital, Department of Radiology, Strasbourg (France); Yacoub, M. [Pellegrin Hospital, Department of Pathology, Bordeaux (France); Bernhard, J.C. [Pellegrin Hospital, Department of Urologic Surgery, Bordeaux (France)

2017-03-15

Mucinous tubular and spindle cell carcinoma (MTSCC) of the kidney is a recently identified renal malignancy. Diagnosis of this rare subtype of renal tumour can be challenging for pathologists, and as such, any additional data would be helpful to improve diagnostic reliability. As imaging features of this new and rare sub-type have not yet been clearly described, the purpose of this study was to describe the main radiologic features on computed tomography (CT) and magnetic resonance imaging (MRI), based jointly on the literature and findings from a multi-institutional retrospective review of pathology and imaging databases. Using a combination of CT/MRI features, diagnosis of MTSCC could be suggested in many cases. A combination of slow enhancement with plateau on dynamic contrast-enhanced CT/MRI, intermediate to high T2 signal intensity contrasting with low apparent diffusion coefficient values on MRI appeared evocative of this diagnosis. (orig.)

Recombinant human erythropoietin in humans down-regulates proximal renal tubular reabsorption and causes a fall in glomerular filtration rate

DEFF Research Database (Denmark)

Olsen, Niels Vidiendal; Aachmann-Andersen, Niels Jacob; Oturai, Peter

2010-01-01

HuEPO for 28 days in doses raising the hematocrit to 48.3 (4.1) %. Renal clearance studies with urine collections (N = 8) were done at baseline and at days 4, 11, 29, and 42. Glomerular filtration rate (GFR) was measured by (51)Cr-EDTA. Renal clearance of lithium (C(Li)) was used as an index of proximal...... tubular outflow and to assess segmental renal tubular handling of sodium and water. rHuEPO-induced increases in hematocrit occurred from day 10 onwards and was caused by both an increase in red cell volume and a fall in plasma volume. Well before that (from day 2 and throughout the treatment time), r...... and water (APR = GFR - C(Li), P

Plastic deformation of tubular crystals by dislocation glide.

Science.gov (United States)

Beller, Daniel A; Nelson, David R

2016-09-01

Tubular crystals, two-dimensional lattices wrapped into cylindrical topologies, arise in many contexts, including botany and biofilaments, and in physical systems such as carbon nanotubes. The geometrical principles of botanical phyllotaxis, describing the spiral packings on cylinders commonly found in nature, have found application in all these systems. Several recent studies have examined defects in tubular crystals associated with crystalline packings that must accommodate a fixed tube radius. Here we study the mechanics of tubular crystals with variable tube radius, with dislocations interposed between regions of different phyllotactic packings. Unbinding and separation of dislocation pairs with equal and opposite Burgers vectors allow the growth of one phyllotactic domain at the expense of another. In particular, glide separation of dislocations offers a low-energy mode for plastic deformations of solid tubes in response to external stresses, reconfiguring the lattice step by step. Through theory and simulation, we examine how the tube's radius and helicity affects, and is in turn altered by, the mechanics of dislocation glide. We also discuss how a sufficiently strong bending rigidity can alter or arrest the deformations of tubes with small radii.

Tubular Carcinoma of the Breast: Advantages and Limitations of Breast Tomosynthesis

Directory of Open Access Journals (Sweden)

Filipa Vilaverde

2016-01-01

Full Text Available Tubular carcinoma of the breast is a rare variant of invasive ductal carcinoma. We report a case of 42-year-old asymptomatic female with a histopathological proven multifocal tubular carcinoma, studied by mammography, Tomosynthesis, Ultrasound, and Magnetic Resonance. Herein, we discuss the advantages and limitations of Tomosynthesis, an emerging imaging technique, in this particular case.

Tubular Carcinoma of the Breast: Advantages and Limitations of Breast Tomosynthesis

Science.gov (United States)

Rocha, Ana; Reis, Alcinda

2016-01-01

Tubular carcinoma of the breast is a rare variant of invasive ductal carcinoma. We report a case of 42-year-old asymptomatic female with a histopathological proven multifocal tubular carcinoma, studied by mammography, Tomosynthesis, Ultrasound, and Magnetic Resonance. Herein, we discuss the advantages and limitations of Tomosynthesis, an emerging imaging technique, in this particular case. PMID:28116205

IBMX protects human proximal tubular epithelial cells from hypoxic stress through suppressing hypoxia-inducible factor-1α expression.

Science.gov (United States)

Hasan, Arif Ul; Kittikulsuth, Wararat; Yamaguchi, Fuminori; Musarrat Ansary, Tuba; Rahman, Asadur; Shibayama, Yuki; Nakano, Daisuke; Hitomi, Hirofumi; Tokuda, Masaaki; Nishiyama, Akira

2017-09-15

Hypoxia predisposes renal fibrosis. This study was conducted to identify novel approaches to ameliorate the pathogenic effect of hypoxia. Using human proximal tubular epithelial cells we showed that a pan-phosphodiesterase (PDE) inhibitor, 3-isobutyl-1-methylxanthine (IBMX) dose and time dependently downregulated hypoxia-inducible factor 1α (HIF-1α) mRNA expression, which was further augmented by addition of a transcriptional inhibitor, actinomycin D. IBMX also increased the cellular cyclic adenosine monophosphate (cAMP) level. Luciferase assay showed that blocking of protein kinase A (PKA) using H89 reduced, while 8-Br-cAMP agonized the repression of HIF-1α promoter activity in hypoxic condition. Deletion of cAMP response element binding sites from the HIF-1α promoter abrogated the effect of IBMX. Western blot and immunofluorescent study confirmed that the CoCl 2 induced increased HIF-1α protein in whole cell lysate and in nucleus was reduced by the IBMX. Through this process, IBMX attenuated both CoCl 2 and hypoxia induced mRNA expressions of two pro-fibrogenic factors, platelet-derived growth factor B and lysyl oxidase. Moreover, IBMX reduced production of a mesenchymal transformation factor, β-catenin; as well as protected against hypoxia induced cell-death. Taken together, our study showed novel evidence that the PDE inhibitor IBMX can downregulate the transcription of HIF-1α, and thus may attenuate hypoxia induced renal fibrosis. Copyright © 2017 Elsevier Inc. All rights reserved.

Membrane organization determines barrier properties of endothelial cells and short-chain sphingolipid-facilitated doxorubicin influx.

Science.gov (United States)

van Hell, A J; Klymchenko, A; Gueth, D M; van Blitterswijk, W J; Koning, G A; Verheij, M

2014-09-01

The endothelial lining and its outer lipid membrane are the first major barriers drug molecules encounter upon intravenous administration. Our previous work identified lipid analogs that counteract plasma membrane barrier function for a series of amphiphilic drugs. For example, short-chain sphingolipids (SCS), like N-octanoyl-glucosylceramide, effectively elevated doxorubicin accumulation in tumor cells, both in vitro and in vivo, and in endothelial cells, whereas other (normal) cells remained unaffected. We hypothesize here that local membrane lipid composition and the degree of lipid ordering define SCS efficacy in individual cells. To this end, we study the differential effect of SCS on bovine aortic endothelial cells (BAEC) in its confluent versus proliferative state, as a model system. While their (plasma membrane) lipidome stays remarkably unaltered when BAECs reach confluency, their lipids segregate to form apical and basolateral domains. Using probe NR12S, we reveal that lipids in the apical membrane are more condensed/liquid-ordered. SCS preferentially attenuate the barrier posed by these condensed membranes and facilitate doxorubicin influx in these particular membrane regions. We confirm these findings in MDCK cells and artificial membranes. In conclusion, SCS-facilitated drug traversal acts on condensed membrane domains, elicited by confluency in resting endothelium. Copyright © 2014 Elsevier B.V. All rights reserved.

Amelioration of renal ischaemia-reperfusion injury by liposomal delivery of curcumin to renal tubular epithelial and antigen-presenting cells.

Science.gov (United States)

Rogers, N M; Stephenson, M D; Kitching, A R; Horowitz, J D; Coates, P T H

2012-05-01

Renal ischaemia-reperfusion (IR) injury is an inevitable consequence of renal transplantation, causing significant graft injury, increasing the risk of rejection and contributing to poor long-term graft outcome. Renal injury is mediated by cytokine and chemokine synthesis, inflammation and oxidative stress resulting from activation of the NF-κB pathway. We utilized liposomal incorporation of a potent inhibitor of the NF-κB pathway, curcumin, to target delivery to renal tubular epithelial and antigen-presenting cells. Liposomes containing curcumin were administered before bilateral renal ischaemia in C57/B6 mice, with subsequent reperfusion. Renal function was assessed from plasma levels of urea and creatinine, 4 and 24 h after reperfusion. Renal tissue was examined for NF-κB activity and oxidative stress (histology, immunostaining) and for apoptosis (TUNEL). Cytokines and chemokines were measured by RT-PCR and Western blotting. Liposomal curcumin significantly improved serum creatinine, reduced histological injury and cellular apoptosis and lowered Toll-like receptor-4, heat shock protein-70 and TNF-α mRNA expression. Liposomal curcumin also reduced neutrophil infiltration and diminished inflammatory chemokine expression. Curcumin liposomes reduced intracellular superoxide generation and increased superoxide dismutase levels, decreased inducible NOS mRNA expression and 3-nitrotyrosine staining consistent with limitations in nitrosative stress and inhibited renal tubular mRNA and protein expression of thioredoxin-interacting protein. These actions of curcumin were mediated by inhibition of NF-κB, MAPK and phospho-S6 ribosomal protein. Liposomal delivery of curcumin promoted effective, targeted delivery of this non-toxic compound that provided cytoprotection via anti-inflammatory and multiple antioxidant mechanisms following renal IR injury. © 2011 The Authors. British Journal of Pharmacology © 2011 The British Pharmacological Society.

Mechanisms of pertussis toxin-induced barrier dysfunction in bovine pulmonary artery endothelial cell monolayers.

Science.gov (United States)

Patterson, C E; Stasek, J E; Schaphorst, K L; Davis, H W; Garcia, J G

1995-06-01

We have previously characterized several G proteins in endothelial cells (EC) as substrates for the ADP-ribosyltransferase activity of both pertussis (PT) and cholera toxin and described the modulation of key EC physiological responses, including gap formation and barrier function, by these toxins. In this study, we investigated the mechanisms involved in PT-mediated regulation of bovine pulmonary artery endothelial cells barrier function. PT caused a dose-dependent increase in albumin transfer, dependent upon action of the holotoxin, since neither the heat-inactivated PT, the isolated oligomer, nor the protomer induced EC permeability. PT-induced gap formation and barrier dysfunction were additive to either thrombin- or thrombin receptor-activating peptide-induced permeability, suggesting that thrombin and PT utilize distinct mechanisms. PT did not result in Ca2+ mobilization or alter either basal or thrombin-induced myosin light chain phosphorylation. However, PT stimulated protein kinase C (PKC) activation, and both PKC downregulation and PKC inhibition attenuated PT-induced permeability, indicating that PKC activity is involved in PT-induced barrier dysfunction. Like thrombin-induced permeability, the PT effect was blocked by prior increases in adenosine 3',5'-cyclic monophosphate. Thus PT-catalyzed ADP-ribosylation of a G protein (possibly other than Gi) may regulate cytoskeletal protein interactions, leading to EC barrier dysfunction.

Effect of section shape on frequencies of natural oscillations of tubular springs

Science.gov (United States)

Pirogov, S. P.; Chuba, A. Yu; Cherentsov, D. A.

2018-05-01

The necessity of determining the frequencies of natural oscillations of manometric tubular springs is substantiated. Based on the mathematical model and computer program, numerical experiments were performed that allowed us to reveal the effect of geometric parameters on the frequencies of free oscillations of manometric tubular springs.

Compressibility effects in packed and open tubular gas and supercritical fluid chromatography

NARCIS (Netherlands)

Janssen, J.G.M.; Snijders, H.M.J.; Cramers, C.A.; Schoenmakers, P.J.

1992-01-01

The influence of the pressure drop on the efficiency and speed of anal. in packed and open tubular supercrit. fluid chromatog. (SFC) is described: methods previously developed to describe the effects of mobile phase compressibility on the performance of open tubular columns in SFC have been extended

Breaking down the barriers to commercialization of fuel cells in transportation through Government - industry R&D programs

Energy Technology Data Exchange (ETDEWEB)

Chalk, S.G. [Dept. of Energy, Washington, DC (United States); Venkateswaran, S.R. [Energetics, Inc., Columbia, MD (United States)

1996-12-31

PEM fuel cell technology is rapidly emerging as a viable propulsion alternative to the internal combustion engine. Fuel cells offer the advantages of low emissions, high efficiency, fuel flexibility, quiet and continuous operation, and modularity. Over the last decade, dramatic advances have been achieved in the performance and cost of PEM fuel cell technologies for automotive applications. However, significant technical barriers remain to making fuel cell propulsion systems viable alternatives to the internal combustion engine. This paper focuses on the progress achieved and remaining technical barriers while highlighting Government-industry R&D efforts that are accelerating fuel cell technology toward commercialization.

Arsenic compromises conducting airway epithelial barrier properties in primary mouse and immortalized human cell cultures.

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Cara L Sherwood

Full Text Available Arsenic is a lung toxicant that can lead to respiratory illness through inhalation and ingestion, although the most common exposure is through contaminated drinking water. Lung effects reported from arsenic exposure include lung cancer and obstructive lung disease, as well as reductions in lung function and immune response. As part of their role in innate immune function, airway epithelial cells provide a barrier that protects underlying tissue from inhaled particulates, pathogens, and toxicants frequently found in inspired air. We evaluated the effects of a five-day exposure to environmentally relevant levels of arsenic {<4μM [~300 μg/L (ppb] as NaAsO2} on airway epithelial barrier function and structure. In a primary mouse tracheal epithelial (MTE cell model we found that both micromolar (3.9 μM and submicromolar (0.8 μM arsenic concentrations reduced transepithelial resistance, a measure of barrier function. Immunofluorescent staining of arsenic-treated MTE cells showed altered patterns of localization of the transmembrane tight junction proteins claudin (Cl Cl-1, Cl-4, Cl-7 and occludin at cell-cell contacts when compared with untreated controls. To better quantify arsenic-induced changes in tight junction transmembrane proteins we conducted arsenic exposure experiments with an immortalized human bronchial epithelial cell line (16HBE14o-. We found that arsenic exposure significantly increased the protein expression of Cl-4 and occludin as well as the mRNA levels of Cl-4 and Cl-7 in these cells. Additionally, arsenic exposure resulted in altered phosphorylation of occludin. In summary, exposure to environmentally relevant levels of arsenic can alter both the function and structure of airway epithelial barrier constituents. These changes likely contribute to the observed arsenic-induced loss in basic innate immune defense and increased infection in the airway.

Bioinspired coupled helical coils for soft tissue engineering of tubular structures - Improved mechanical behavior of tubular collagen type I templates.

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Janke, H P; Bohlin, J; Lomme, R M L M; Mihaila, S M; Hilborn, J; Feitz, W F J; Oosterwijk, E

2017-09-01

The design of constructs for tubular tissue engineering is challenging. Most biomaterials need to be reinforced with supporting structures such as knittings, meshes or electrospun material to comply with the mechanical demands of native tissues. In this study, coupled helical coils (CHCs) were manufactured to mimic collagen fiber orientation as found in nature. Monofilaments of different commercially available biodegradable polymers were wound and subsequently fused, resulting in right-handed and left-handed polymer helices fused together in joints where the filaments cross. CHCs of different polymer composition were tested to determine the tensile strength, strain recovery, hysteresis, compressive strength and degradation of CHCs of different composition. Subsequently, seamless and stable hybrid constructs consisting of PDSII® USP 2-0 CHCs embedded in porous collagen type I were produced. Compared to collagen alone, this hybrid showed superior strain recovery (93.5±0.9% vs 71.1±12.6% in longitudinal direction; 87.1±6.6% vs 57.2±4.6% in circumferential direction) and hysteresis (18.9±2.7% vs 51.1±12.0% in longitudinal direction; 11.5±4.6% vs 46.3±6.3% in circumferential direction). Furthermore, this hybrid construct showed an improved Young's modulus in both longitudinal (0.5±0.1MPavs 0.2±0.1MPa; 2.5-fold) and circumferential (1.65±0.07MPavs (2.9±0.3)×10 -2 MPa; 57-fold) direction, respectively, compared to templates created from collagen alone. Moreover, hybrid template characteristics could be modified by changing the CHC composition and CHCs were produced showing a mechanical behavior similar to the native ureter. CHC-enforced templates, which are easily tunable to meet different demands may be promising for tubular tissue engineering. Most tubular constructs lack sufficient strength and tunability to comply with the mechanical demands of native tissues. Therefore, we embedded coupled helical coils (CHCs) produced from biodegradable polymers - to

Research on typical topologies of a tubular horizontal-gap passive magnetic levitation vibration isolator

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Zhou Yiheng

2017-01-01

Full Text Available Magnetic levitation vibration isolators have attracted more and more attention in the field of high-precision measuring and machining equipment. In this paper, we describe a tubular horizontal-gap passive magnetic levitation vibration isolator. Four typical topologies of the tubular horizontal-gap passive magnetic levitation vibration isolator are proposed. The analytical expression of magnetic force is derived. The relationship between levitation force, force density, force ripple and major structural parameters are analysed by finite element method, which is conductive to the design and optimization of the tubular horizontal-gap passive magnetic levitation vibration isolator. The force characteristics of different topologies of the tubular horizontal-gap passive magnetic levitation vibration isolator are compared and evaluated from the aspect of force density, force ripple and manufacturability. In comparison with conventional passive magnetic levitation vibration isolators, the proposed tubular horizontal-gap passive magnetic levitation vibration isolator shows advantage in higher force density.

On Energy Balance and Production Costs in Tubular and Flat Panel Photobioreactors

NARCIS (Netherlands)

Norsker, N.H.; Barbosa, M.J.; Vermue, M.H.; Wijffels, R.H.

2012-01-01

Reducing mixing in both flat panel and tubular photobioreactors can result in a positive net energy balance with state-of-the-art technology and Dutch weather conditions. In the tubular photobioreactor, the net energy balance becomes positive at velocities <0.3 ms-1, at which point the biomass

Hyperammonemia associated with distal renal tubular acidosis or urinary tract infection: a systematic review.

Science.gov (United States)

Clericetti, Caterina M; Milani, Gregorio P; Lava, Sebastiano A G; Bianchetti, Mario G; Simonetti, Giacomo D; Giannini, Olivier

2018-03-01

Hyperammonemia usually results from an inborn error of metabolism or from an advanced liver disease. Individual case reports suggest that both distal renal tubular acidosis and urinary tract infection may also result in hyperammonemia. A systematic review of the literature on hyperammonemia secondary to distal renal tubular acidosis and urinary tract infection was conducted. We identified 39 reports on distal renal tubular acidosis or urinary tract infections in association with hyperammonemia published between 1980 and 2017. Hyperammonemia was detected in 13 children with distal renal tubular acidosis and in one adult patient with distal renal tubular acidosis secondary to primary hyperparathyroidism. In these patients a negative relationship was observed between circulating ammonia and bicarbonate levels (P urinary tract infection was complicated by acute hyperammonemia and symptoms and signs of acute neuronal dysfunction, such as an altered level of consciousness, convulsions and asterixis, often associated with signs of brain edema, such as anorexia and vomiting. Urea-splitting bacteria were isolated in 28 of the 31 cases. The urinary tract was anatomically or functionally abnormal in 30 of these patients. This study reveals that both altered distal renal tubular acidification and urinary tract infection may be associated with relevant hyperammonemia in both children and adults.

Diffuse Lymphomatous Infiltration of Kidney Presenting as Renal Tubular Acidosis and Hypokalemic Paralysis: Case Report

Science.gov (United States)

Jhamb, Rajat; Gupta, Naresh; Garg, Sandeep; Kumar, Sachin; Gulati, Sameer; Mishra, Deepak; Beniwal, Pankaj

2007-01-01

We report the case of a 22-year-old woman who presented with acute onset flaccid quadriparesis. Physical examination showed mild pallor with cervical and axillary lymphadenopathy, hepatomegaly, and bilateral smooth enlarged kidneys. Neurological examination revealed lower motor neuron muscle weakness in all the four limbs with hyporeflexia and normal sensory examination. Laboratory investigations showed anemia, severe hypokalemia, and metabolic acidosis. Urinalysis showed a specific gravity of 1.010, pH of 7.0, with a positive urine anion gap. Ultrasound revealed hepatosplenomegaly with bilateral enlarged smooth kidneys. Renal biopsy was consistent with the diagnosis of non-Hodgkin lymphoma (B cell type). Metabolic acidosis, alkaline urine, and severe hypokalemia due to excessive urinary loss in our patient were suggestive of distal renal tubular acidosis. Renal involvement in lymphoma is usually subclinical and clinically overt renal disease is rare. Diffuse lymphomatous infiltration of the kidneys may cause tubular dysfunction and present with hypokalemic paralysis. PMID:18074421

Simulation of a tubular solid oxide fuel cell stack using AspenPlusTM unit operation models

International Nuclear Information System (INIS)

Zhang, W.; Croiset, E.; Douglas, P.L.; Fowler, M.W.; Entchev, E.

2005-01-01

The design of a fuel cell system involves both optimization of the fuel cell stack and the balance of plant with respect to efficiency and economics. Many commercially available process simulators, such as AspenPlus TM , can facilitate the analysis of a solid oxide fuel cell (SOFC) system. A SOFC system may include fuel pre-processors, heat exchangers, turbines, bottoming cycles, etc., all of which can be very effectively modelled in process simulation software. The current challenge is that AspenPlus TM or any other commercial process simulators do not have a model of a basic SOFC stack. Therefore, to enable performing SOFC system simulation using one of these simulators, one must construct an SOFC stack model that can be implemented in them. The most common approach is to develop a complete SOFC model in a programming language, such as Fortran, Visual Basic or C++, first and then link it to a commercial process simulator as a user defined model or subroutine. This paper introduces a different approach to the development of a SOFC model by utilizing existing AspenPlus TM functions and existing unit operation modules. The developed ''AspenPlus TM SOFC'' model is able to provide detailed thermodynamic and parametric analyses of the SOFC operation and can easily be extended to study the entire power plant consisting of the SOFC and the balance of plant without the requirement for linking with other software. Validation of this model is performed by comparison to a Siemens-Westinghouse 100 kW class tubular SOFC stack. Sensitivity analyses of major operating parameters, such as utilization factor (U f ), current density (I c ) and steam-carbon ratio (S/C), were performed using the developed model, and the results are discussed in this paper

A Tubular Biomaterial Construct Exhibiting a Negative Poisson's Ratio.

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Jin Woo Lee

Full Text Available Developing functional small-diameter vascular grafts is an important objective in tissue engineering research. In this study, we address the problem of compliance mismatch by designing and developing a 3D tubular construct that has a negative Poisson's ratio νxy (NPR. NPR constructs have the unique ability to expand transversely when pulled axially, thereby resulting in a highly-compliant tubular construct. In this work, we used projection stereolithography to 3D-print a planar NPR sheet composed of photosensitive poly(ethylene glycol diacrylate biomaterial. We used a step-lithography exposure and a stitch process to scale up the projection printing process, and used the cut-missing rib unit design to develop a centimeter-scale NPR sheet, which was rolled up to form a tubular construct. The constructs had Poisson's ratios of -0.6 ≤ νxy ≤ -0.1. The NPR construct also supports higher cellular adhesion than does the construct that has positive νxy. Our NPR design offers a significant advance in the development of highly-compliant vascular grafts.

Simulation of temperature effect on microalgae culture in a tubular photo bioreactor for local solar irradiance

Science.gov (United States)

Shahriar, M.; Deb, Ujjwal Kumar; Rahman, Kazi Afzalur

2017-06-01

Microalgae based biofuel is now an emerging source of renewable energy alternative to the fossil fuel. This paper aims to present computational model of microalgae culture taking effect of solar irradiance and corresponding temperature in a photo bioreactor (PBR). As microalgae is a photosynthetic microorganism, so irradiance of sunlight is one of the important limiting factors for the proper growth of microalgae cells as temperature is associated with it. We consider the transient behaviour of temperature inside the photo bioreactor for a microalgae culture. The optimum range of temperature for outdoor cultivation of microalgae is about 16-35°c and out of this range the cell growth inhibits. Many correlations have already been established to investigate the heat transfer phenomena inside a tubular PBR. However, none of them are validated yet numerically by using a user defined function in a simulated model. A horizontal tubular PBR length 20.5m with radius 0.05m has taken account to investigate the temperature effect for the growth of microalgae cell. As the solar irradiance varies at any geographic latitude for a year so an empirical relation is established between local solar irradiance and temperature to simulate the effect. From our simulation, we observed that the growth of microalgae has a significant effect of temperature and the solar irradiance of our locality is suitable for the culture of microalgae.

A 3D-printed microbial cell culture platform with in situ PEGDA hydrogel barriers for differential substrate delivery.

Science.gov (United States)

Kadilak, Andrea L; Rehaag, Jessica C; Harrington, Cameron A; Shor, Leslie M

2017-09-01

Additive manufacturing, or 3D-printing techniques have recently begun to enable simpler, faster, and cheaper production of millifluidic devices at resolutions approaching 100-200  μ m. At this resolution, cell culture devices can be constructed that more accurately replicate natural environments compared with conventional culturing techniques. A number of microfluidics researchers have begun incorporating additive manufacturing into their work, using 3D-printed devices in a wide array of chemical, fluidic, and even some biological applications. Here, we describe a 3D-printed cell culture platform and demonstrate its use in culturing Pseudomonas putida KT2440 bacteria for 44 h under a differential substrate gradient. Polyethylene glycol diacrylate (PEGDA) hydrogel barriers are patterned in situ within a 3D-printed channel. Transport of the toluidine blue tracer dye through the hydrogel barriers is characterized. Nutrients and oxygen were delivered to cells in the culture region by diffusion through the PEGDA hydrogel barriers from adjacent media or saline perfusion channels. Expression of green fluorescent protein by P. putida KT2440 enabled real time visualization of cell density within the 3D-printed channel, and demonstrated cells were actively expressing protein over the course of the experiment. Cells were observed clustering near hydrogel barrier boundaries where fresh substrate and oxygen were being delivered via diffusive transport, but cells were unable to penetrate the barrier. The device described here provides a versatile and easy to implement platform for cell culture in readily controlled gradient microenvironments. By adjusting device geometry and hydrogel properties, this platform could be further customized for a wide variety of biological applications.

Porcine proximal tubular cells (LLC-PK1) are able to tolerate high levels of lithium chloride in vitro: assessment of the influence of 1-20 mM LiCl on cell death and alterations in cell biology and biochemistry.

Science.gov (United States)

Lucas, Kirsten C; Hart, David A; Becker, Rolf W

2010-01-25

Lithium, a prophylactic drug for the treatment of bipolar disorder, is prescribed with caution due to its side effects, including renal damage. In this study porcine LLC-PK1 renal tubular cells were used to establish the direct toxicity of lithium on proximal cells and gain insights into the molecular mechanisms involved. In the presence of LiCl, cell proliferation exhibited insignificant decreases in a concentration-dependent manner, but once confluent, constant cell numbers were observed. Cell cycle studies indicated a small dose-dependent accumulation of cells in the G2/M stage after 24 h, as well as an increase in cells in the G0/G1 phase after treatment with 1-10 mM LiCl, but not at 20 mM LiCl. No evidence of apoptosis was observed based on cell morphology or DNA fragmentation studies, or evidence of protein expression changes for Bax, Bcl-2, and p53 proteins using immunocytochemistry. In addition caspases 3, 8 and 9 activity remained unaltered between control and lithium-treated cultures. To conclude, exposure to high concentrations of lithium did not result in overt toxic effects to LLC-PK1 renal cells, although LiCl did alter some aspects of cell behaviour, which could potentially influence function over time.

Undulating tubular liposomes through incorporation of a synthetic skin ceramide into phospholipid bilayers.

Science.gov (United States)

Xu, Peng; Tan, Grace; Zhou, Jia; He, Jibao; Lawson, Louise B; McPherson, Gary L; John, Vijay T

2009-09-15

Nonspherical liposomes were prepared by doping L-alpha-phosphatidylcholine (PC) with ceramide VI (a skin lipid). Cryo-transmission electron microscopy shows the liposome shape changing from spherical to an undulating tubular morphology, when the amount of ceramide VI is increased. The formation of tubular liposomes is energetically favorable and is attributed to the association of ceramide VI with PC creating regions of lower curvature. Since ceramides are the major component of skin lipids in the stratum corneum, tubular liposomes containing ceramide may potentially serve as self-enhanced nanocarriers for transdermal delivery.

Hypokalaemia and Renal Tubular Acidosis due to Abuse of Nurofen Plus

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M. J. Blackstock

2012-01-01

Full Text Available Nurofen Plus is a common analgesic containing ibuprofen and codeine. We present a case of a 38-year-old lady who developed renal tubular acidosis with severe hypokalaemia, after chronic abuse of Nurofen Plus tablets. She presented with confusion and profound biochemical abnormalities requiring critical care admission for electrolyte replacement. Ibuprofen causes renal tubular acidosis due to its effects on carbonic anhydrase activity.

Relaxin attenuates aristolochic acid induced human tubular epithelial cell apoptosis in vitro by activation of the PI3K/Akt signaling pathway.

Science.gov (United States)

Xie, Xiang-Cheng; Zhao, Ning; Xu, Qun-Hong; Yang, Xiu; Xia, Wen-Kai; Chen, Qi; Wang, Ming; Fei, Xiao

2017-06-01

Aristolochic acid nephropathy remains a leading cause of chronic kidney disease (CKD), however few treatment strategies exist. Emerging evidence has shown that H2 relaxin (RLX) possesses powerful antifibrosis and anti-apoptotic properties, therefore we aimed to investigate whether H2 relaxin can be employed to reduce AA-induced cell apoptosis. Human proximal tubular epithelial (HK-2) cells exposed to AA-I were treated with or without administration of H2 RLX. Cell viability was examined using the WST-8 assay. Apoptotic morphologic alterations were observed using the Hoechst 33342 staining method. Apoptosis was detected using flow cytometry. The expression of caspase 3, caspase 8, caspase 9, ERK1/2, Bax, Bcl-2, and Akt proteins was determined by Western blot. Co-treatment with RLX reversed the increased apoptosis observed in the AA-I only treated group. RLX restored expression of phosphorylated Akt which found to be decreased in the AA-I only treated cells. RLX co-treatment led to a decrease in the Bax/Bcl-2 ratio as well as the cleaved form of caspase-3 compared to the AA-I only treated cells. This anti-apoptotic effect of RLX was attenuated by co-administration of the Akt inhibitor LY294002. The present study demonstrated H2 RLX can decrease AA-I induced apoptosis through activation of the PI3K/Akt signaling pathway.

Arctigenin from Fructus Arctii (Seed of Burdock) Reinforces Intestinal Barrier Function in Caco-2 Cell Monolayers

Science.gov (United States)

Shin, Hee Soon; Jung, Sun Young; Back, Su Yeon; Do, Jeong-Ryong; Shon, Dong-Hwa

2015-01-01

Fructus Arctii is used as a traditional herbal medicine to treat inflammatory diseases in oriental countries. This study aimed to investigate effect of F. Arctii extract on intestinal barrier function in human intestinal epithelial Caco-2 cells and to reveal the active component of F. Arctii. We measured transepithelial electrical resistance (TEER) value (as an index of barrier function) and ovalbumin (OVA) permeation (as an index of permeability) to observe the changes of intestinal barrier function. The treatment of F. Arctii increased TEER value and decreased OVA influx on Caco-2 cell monolayers. Furthermore, we found that arctigenin as an active component of F. Arctii increased TEER value and reduced permeability of OVA from apical to the basolateral side but not arctiin. In the present study, we revealed that F. Arctii could enhance intestinal barrier function, and its active component was an arctigenin on the functionality. We expect that the arctigenin from F. Arctii could contribute to prevention of inflammatory, allergic, and infectious diseases by reinforcing intestinal barrier function. PMID:26550018

Arctigenin from Fructus Arctii (Seed of Burdock Reinforces Intestinal Barrier Function in Caco-2 Cell Monolayers

Directory of Open Access Journals (Sweden)

Hee Soon Shin

2015-01-01

Full Text Available Fructus Arctii is used as a traditional herbal medicine to treat inflammatory diseases in oriental countries. This study aimed to investigate effect of F. Arctii extract on intestinal barrier function in human intestinal epithelial Caco-2 cells and to reveal the active component of F. Arctii. We measured transepithelial electrical resistance (TEER value (as an index of barrier function and ovalbumin (OVA permeation (as an index of permeability to observe the changes of intestinal barrier function. The treatment of F. Arctii increased TEER value and decreased OVA influx on Caco-2 cell monolayers. Furthermore, we found that arctigenin as an active component of F. Arctii increased TEER value and reduced permeability of OVA from apical to the basolateral side but not arctiin. In the present study, we revealed that F. Arctii could enhance intestinal barrier function, and its active component was an arctigenin on the functionality. We expect that the arctigenin from F. Arctii could contribute to prevention of inflammatory, allergic, and infectious diseases by reinforcing intestinal barrier function.

Fabrication and preliminary study of a biomimetic tri-layer tubular graft based on fibers and fiber yarns for vascular tissue engineering.

Science.gov (United States)

Wu, Tong; Zhang, Jialing; Wang, Yuanfei; Li, Dandan; Sun, Binbin; El-Hamshary, Hany; Yin, Meng; Mo, Xiumei

2018-01-01

Designing a biomimetic and functional tissue-engineered vascular graft has been urgently needed for repairing and regenerating defected vascular tissues. Utilizing a multi-layered vascular scaffold is commonly considered an effective way, because multi-layered scaffolds can easily simulate the structure and function of natural blood vessels. Herein, we developed a novel tri-layer tubular graft consisted of Poly(L-lactide-co-caprolactone)/collagen (PLCL/COL) fibers and Poly(lactide-co-glycolide)/silk fibroin (PLGA/SF) yarns via a three-step electrospinning method. The tri-layer vascular graft consisted of PLCL/COL aligned fibers in inner layer, PLGA/SF yarns in middle layer, and PLCL/COL random fibers in outer layer. Each layer possessed tensile mechanical strength and elongation, and the entire tubular structure provided tensile and compressive supports. Furthermore, the human umbilical vein endothelial cells (HUVECs) and smooth muscle cells (SMCs) proliferated well on the materials. Fluorescence staining images demonstrated that the axially aligned PLCL/COL fibers prearranged endothelium morphology in lumen and the circumferential oriented PLGA/SF yarns regulated SMCs organization along the single yarns. The outside PLCL/COL random fibers performed as the fixed layer to hold the entire tubular structure. The in vivo results showed that the tri-layer vascular graft supported cell infiltration, scaffold biodegradation and abundant collagen production after subcutaneous implantation for 10weeks, revealing the optimal biocompatibility and tissue regenerative capability of the tri-layer graft. Therefore, the specially designed tri-layer vascular graft will be beneficial to vascular reconstruction. Copyright © 2017. Published by Elsevier B.V.

Effects of SGLT2 inhibition in human kidney proximal tubular cells--renoprotection in diabetic nephropathy?

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Usha Panchapakesan

Full Text Available Sodium/glucose cotransporter 2 (SGLT2 inhibitors are oral hypoglycemic agents used to treat patients with diabetes mellitus. SGLT2 inhibitors block reabsorption of filtered glucose by inhibiting SGLT2, the primary glucose transporter in the proximal tubular cell (PTC, leading to glycosuria and lowering of serum glucose. We examined the renoprotective effects of the SGLT2 inhibitor empagliflozin to determine whether blocking glucose entry into the kidney PTCs reduced the inflammatory and fibrotic responses of the cell to high glucose. We used an in vitro model of human PTCs. HK2 cells (human kidney PTC line were exposed to control 5 mM, high glucose (HG 30 mM or the profibrotic cytokine transforming growth factor beta (TGFβ1; 0.5 ng/ml in the presence and absence of empagliflozin for up to 72 h. SGLT1 and 2 expression and various inflammatory/fibrotic markers were assessed. A chromatin immunoprecipitation assay was used to determine the binding of phosphorylated smad3 to the promoter region of the SGLT2 gene. Our data showed that TGFβ1 but not HG increased SGLT2 expression and this occurred via phosphorylated smad3. HG induced expression of Toll-like receptor-4, increased nuclear deoxyribonucleic acid binding for nuclear factor kappa B (NF-κB and activator protein 1, induced collagen IV expression as well as interleukin-6 secretion all of which were attenuated with empagliflozin. Empagliflozin did not reduce high mobility group box protein 1 induced NF-κB suggesting that its effect is specifically related to a reduction in glycotoxicity. SGLT1 and GLUT2 expression was not significantly altered with HG or empagliflozin. In conclusion, empagliflozin reduces HG induced inflammatory and fibrotic markers by blocking glucose transport and did not induce a compensatory increase in SGLT1/GLUT2 expression. Although HG itself does not regulate SGLT2 expression in our model, TGFβ increases SGLT2 expression through phosphorylated smad3.

The B-Cell Follicle in HIV Infection: Barrier to a Cure.

Science.gov (United States)

Bronnimann, Matthew P; Skinner, Pamela J; Connick, Elizabeth

2018-01-01

The majority of HIV replication occurs in secondary lymphoid organs (SLOs) such as the spleen, lymph nodes, and gut-associated lymphoid tissue. Within SLOs, HIV RNA + cells are concentrated in the B-cell follicle during chronic untreated infection, and emerging data suggest that they are a major source of replication in treated disease as well. The concentration of HIV RNA + cells in the B-cell follicle is mediated by several factors. Follicular CD4 + T-cell subsets including T-follicular helper cells and T-follicular regulatory cells are significantly more permissive to HIV than extrafollicular subsets. The B cell follicle also contains a large reservoir of extracellular HIV virions, which accumulate on the surface of follicular dendritic cells (FDCs) in germinal centers. FDC-bound HIV virions remain infectious even in the presence of neutralizing antibodies and can persist for months or even years. Moreover, the B-cell follicle is semi-immune privileged from CTL control. Frequencies of HIV- and SIV-specific CTL are lower in B-cell follicles compared to extrafollicular regions as the majority of CTL do not express the follicular homing receptor CXCR5. Additionally, CTL in the B-cell follicle may be less functional than extrafollicular CTL as many exhibit the recently described CD8 T follicular regulatory phenotype. Other factors may also contribute to the follicular concentration of HIV RNA + cells. Notably, the contribution of NK cells and γδ T cells to control and/or persistence of HIV RNA + cells in secondary lymphoid tissue remains poorly characterized. As HIV research moves increasingly toward the development of cure strategies, a greater understanding of the barriers to control of HIV infection in B-cell follicles is critical. Although no strategy has as of yet proven to be effective, a range of novel therapies to address these barriers are currently being investigated including genetically engineered CTL or chimeric antigen receptor T cells that express

The B-Cell Follicle in HIV Infection: Barrier to a Cure

Directory of Open Access Journals (Sweden)

Matthew P. Bronnimann

2018-01-01

Full Text Available The majority of HIV replication occurs in secondary lymphoid organs (SLOs such as the spleen, lymph nodes, and gut-associated lymphoid tissue. Within SLOs, HIV RNA+ cells are concentrated in the B-cell follicle during chronic untreated infection, and emerging data suggest that they are a major source of replication in treated disease as well. The concentration of HIV RNA+ cells in the B-cell follicle is mediated by several factors. Follicular CD4+ T-cell subsets including T-follicular helper cells and T-follicular regulatory cells are significantly more permissive to HIV than extrafollicular subsets. The B cell follicle also contains a large reservoir of extracellular HIV virions, which accumulate on the surface of follicular dendritic cells (FDCs in germinal centers. FDC-bound HIV virions remain infectious even in the presence of neutralizing antibodies and can persist for months or even years. Moreover, the B-cell follicle is semi-immune privileged from CTL control. Frequencies of HIV- and SIV-specific CTL are lower in B-cell follicles compared to extrafollicular regions as the majority of CTL do not express the follicular homing receptor CXCR5. Additionally, CTL in the B-cell follicle may be less functional than extrafollicular CTL as many exhibit the recently described CD8 T follicular regulatory phenotype. Other factors may also contribute to the follicular concentration of HIV RNA+ cells. Notably, the contribution of NK cells and γδ T cells to control and/or persistence of HIV RNA+ cells in secondary lymphoid tissue remains poorly characterized. As HIV research moves increasingly toward the development of cure strategies, a greater understanding of the barriers to control of HIV infection in B-cell follicles is critical. Although no strategy has as of yet proven to be effective, a range of novel therapies to address these barriers are currently being investigated including genetically engineered CTL or chimeric antigen receptor T cells

Testing of tubular goods - a critical review of past and actual testing procedures

Energy Technology Data Exchange (ETDEWEB)

Teodoriu, C. [Texas A and M Univ., Houston, TX (United States); Holzmann, J.; Klaws, M. [TU Clausthal (Germany). Inst. fuer Erdoel- und Erdgastechnik

2007-09-13

Testing of oil country tubular goods (OCTG) is based on standards and offers the user a comparison platform between products of different manufacturers. But, do the standard based testing procedures assume the real loads on OCTG? More likely, the existing standards or recommendations on tubular testing have been evolving together with the new demands on OCTG loading. Since nowadays the oil and gas industry is looking to develop extreme reservoir types (deep water, HP/HT), there is a need of a better understanding and continuous improvement of testing procedures. The following poster proposes an analysis of existing procedures to test tubular goods and then will focus on the future demands on OCTG testing. New loads, as casing fatigue, will be discussed and analyzed based on the authors experience gained during more than 8 years of testing tubular goods at the Clausthal University of Technology, Institute of Petroleum Engineering. (orig.)

Effect of corrosion on the buckling capacity of tubular members

Science.gov (United States)

Øyasæter, F. H.; Aeran, A.; Siriwardane, S. C.; Mikkelsen, O.

2017-12-01

Offshore installations are subjected to harsh marine environment and often have damages from corrosion. Several experimental and numerical studies were performed in the past to estimate buckling capacity of corroded tubular members. However, these studies were either based on limited experimental tests or numerical analyses of few cases resulting in semi-empirical relations. Also, there are no guidelines and recommendations in the currently available design standards. To fulfil this research gap, a new formula is proposed to estimate the residual strength of tubular members considering corrosion and initial geometrical imperfections. The proposed formula is verified with results from finite element analyses performed on several members and for varying corrosion patch parameters. The members are selected to represent the most relevant Eurocode buckling curve for tubular members. It is concluded that corrosion reduces the buckling capacity significantly and the proposed formula can be easily applied by practicing engineers without performing detailed numerical analyses.

Dynamics of catalytic tubular microjet engines: dependence on geometry and chemical environment.

Science.gov (United States)

Li, Jinxing; Huang, Gaoshan; Ye, Mengmeng; Li, Menglin; Liu, Ran; Mei, Yongfeng

2011-12-01

Strain-engineered tubular microjet engines with various geometric dimensions hold interesting autonomous motions in an aqueous fuel solution when propelled by catalytic decomposition of hydrogen peroxide to oxygen and water. The catalytically-generated oxygen bubbles expelled from microtubular cavities propel the microjet step by step in discrete increments. We focus on the dynamics of our tubular microjets in one step and build up a body deformation model to elucidate the interaction between tubular microjets and the bubbles they produce. The average microjet velocity is calculated analytically based on our model and the obtained results demonstrate that the velocity of the microjet increases linearly with the concentration of hydrogen peroxide. The geometric dimensions of the microjet, such as length and radius, also influence its dynamic characteristics significantly. A close consistency between experimental and calculated results is achieved despite a small deviation due to the existence of an approximation in the model. The results presented in this work improve our understanding regarding catalytic motions of tubular microjets and demonstrate the controllability of the microjet which may have potential applications in drug delivery and biology.

Tubular permanent magnet actuators: cogging forces characterization

NARCIS (Netherlands)

Paulides, J.J.H.; Janssen, J.L.G.; Encica, L.; Lomonova, E.A.

2009-01-01

Tubular permanent magnet actuators are evermore used in demanding industrial and automotive applications. However, these actuators can suffer from large cogging forces, which have a destabilizing effect on the servo control system and compromise position and speed control accuracy. This paper

Autophagy inhibitor 3-methyladenine protects against endothelial cell barrier dysfunction in acute lung injury.

Science.gov (United States)

Slavin, Spencer A; Leonard, Antony; Grose, Valerie; Fazal, Fabeha; Rahman, Arshad

2018-03-01

Autophagy is an evolutionarily conserved cellular process that facilitates the continuous recycling of intracellular components (organelles and proteins) and provides an alternative source of energy when nutrients are scarce. Recent studies have implicated autophagy in many disorders, including pulmonary diseases. However, the role of autophagy in endothelial cell (EC) barrier dysfunction and its relevance in the context of acute lung injury (ALI) remain uncertain. Here, we provide evidence that autophagy is a critical component of EC barrier disruption in ALI. Using an aerosolized bacterial lipopolysaccharide (LPS) inhalation mouse model of ALI, we found that administration of the autophagy inhibitor 3-methyladenine (3-MA), either prophylactically or therapeutically, markedly reduced lung vascular leakage and tissue edema. 3-MA was also effective in reducing the levels of proinflammatory mediators and lung neutrophil sequestration induced by LPS. To test the possibility that autophagy in EC could contribute to lung vascular injury, we addressed its role in the mechanism of EC barrier disruption. Knockdown of ATG5, an essential regulator of autophagy, attenuated thrombin-induced EC barrier disruption, confirming the involvement of autophagy in the response. Similarly, exposure of cells to 3-MA, either before or after thrombin, protected against EC barrier dysfunction by inhibiting the cleavage and loss of vascular endothelial cadherin at adherens junctions, as well as formation of actin stress fibers. 3-MA also reversed LPS-induced EC barrier disruption. Together, these data imply a role of autophagy in lung vascular injury and reveal the protective and therapeutic utility of 3-MA against ALI.

Facile Fabrication of Uniform Polyaniline Nanotubes with Tubular Aluminosilicates as Templates

OpenAIRE

Zhang, Long; Liu, Peng

2008-01-01

AbstractThe uniform polyaniline (PANI) nanotubes, with inner diameter, outer diameter, and tubular thickness of 40, 60, and 10 nm, respectively, were prepared successfully by using natural tubular aluminosilicates as templates. The halloysite nanotubes were coated with PANI via the in situ chemical oxidation polymerization. Then the templates were etched with HCl/HF solution. The PANI nanotubes were characterized using FTIR, X-ray diffraction, and transmission electron microscopy. The conduct...

Interface Engineering of Organic Schottky Barrier Solar Cells and Its Application in Enhancing Performances of Planar Heterojunction Solar Cells

Science.gov (United States)

Jin, Fangming; Su, Zisheng; Chu, Bei; Cheng, Pengfei; Wang, Junbo; Zhao, Haifeng; Gao, Yuan; Yan, Xingwu; Li, Wenlian

2016-05-01

In this work, we describe the performance of organic Schottky barrier solar cells with the structure of ITO/molybdenum oxide (MoOx)/boron subphthalocyanine chloride (SubPc)/bathophenanthroline (BPhen)/Al. The SubPc-based Schottky barrier solar cells exhibited a short-circuit current density (Jsc) of 2.59 mA/cm2, an open-circuit voltage (Voc) of 1.06 V, and a power conversion efficiency (PCE) of 0.82% under simulated AM1.5 G solar illumination at 100 mW/cm2. Device performance was substantially enhanced by simply inserting thin organic hole transport material into the interface of MoOx and SubPc. The optimized devices realized a 180% increase in PCE of 2.30% and a peak Voc as high as 1.45 V was observed. We found that the improvement is due to the exciton and electron blocking effect of the interlayer and its thickness plays a vital role in balancing charge separation and suppressing quenching effect. Moreover, applying such interface engineering into MoOx/SubPc/C60 based planar heterojunction cells substantially enhanced the PCE of the device by 44%, from 3.48% to 5.03%. Finally, we also investigated the requirements of the interface material for Schottky barrier modification.

Modeling Group B Streptococcus and Blood-Brain Barrier Interaction by Using Induced Pluripotent Stem Cell-Derived Brain Endothelial Cells

OpenAIRE

Kim, Brandon J.; Bee, Olivia B.; McDonagh, Maura A.; Stebbins, Matthew J.; Palecek, Sean P.; Doran, Kelly S.; Shusta, Eric V.

2017-01-01

ABSTRACT Bacterial meningitis is a serious infection of the central nervous system (CNS) that occurs after bacteria interact with and penetrate the blood-brain barrier (BBB). The BBB is comprised of highly specialized brain microvascular endothelial cells (BMECs) that function to separate the circulation from the CNS and act as a formidable barrier for toxins and pathogens. Certain bacteria, such as Streptococcus agalactiae (group B Streptococcus [GBS]), possess the ability to interact with a...

Ceramide-Induced Apoptosis in Renal Tubular Cells: A Role of Mitochondria and Sphingosine-1-Phoshate

Science.gov (United States)

Ueda, Norishi

2015-01-01

Ceramide is synthesized upon stimuli, and induces apoptosis in renal tubular cells (RTCs). Sphingosine-1 phosphate (S1P) functions as a survival factor. Thus, the balance of ceramide/S1P determines ceramide-induced apoptosis. Mitochondria play a key role for ceramide-induced apoptosis by altered mitochondrial outer membrane permeability (MOMP). Ceramide enhances oligomerization of pro-apoptotic Bcl-2 family proteins, ceramide channel, and reduces anti-apoptotic Bcl-2 proteins in the MOM. This process alters MOMP, resulting in generation of reactive oxygen species (ROS), cytochrome C release into the cytosol, caspase activation, and apoptosis. Ceramide regulates apoptosis through mitogen-activated protein kinases (MAPKs)-dependent and -independent pathways. Conversely, MAPKs alter ceramide generation by regulating the enzymes involving ceramide metabolism, affecting ceramide-induced apoptosis. Crosstalk between Bcl-2 family proteins, ROS, and many signaling pathways regulates ceramide-induced apoptosis. Growth factors rescue ceramide-induced apoptosis by regulating the enzymes involving ceramide metabolism, S1P, and signaling pathways including MAPKs. This article reviews evidence supporting a role of ceramide for apoptosis and discusses a role of mitochondria, including MOMP, Bcl-2 family proteins, ROS, and signaling pathways, and crosstalk between these factors in the regulation of ceramide-induced apoptosis of RTCs. A balancing role between ceramide and S1P and the strategy for preventing ceramide-induced apoptosis by growth factors are also discussed. PMID:25751724

Renal functional reserve and tubular function in patents with type 2 diabetes mellitus

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Dilyara Makhmutrievna Khakimova

2011-06-01

Full Text Available Aim. To study renal functional reserve and partial functions in patents with type 2 diabetes mellitus in the absence of renal lesionsMaterials and methods. We examined 42 patients (17 men and 24 women aged 38-69 (mean 49.8?8.3 years with DM2 4.6?2.6 yr in duration.Control group comprised 32 practically healthy subjects. Intrarenal hemodynamics was estimated from RFR values. Ethanolamine, uric acid, Ca,and P levels were measured in sera and 24-hr urine; daily excretion of ammonia and aminonitrogen in the urine was determined. Results. The patients were divided into 2 groups based on the results of RFR measurement. FRF remained unaltered in 21 patients (mean 60.7?27.6%and decreased in the absence of filtration reserve in 20 (-25.8?23.4%. Correlation analysis revealed the relationship of lipid metabolism and abdominalobesity with the renal tubular function and intraglomerular hemodynamics. Conclusion. Examination of DM2 patients without clinical and laboratory signs of renal lesions revealed compromised function of all nephron compartments,viz. intraglomerular hypertension, impaired stability of renal cell membranes, and tubular dysfunction. The latter is related to hemodynamic disturbances.

Large tubular colonic duplication in an adult treated with a small midline incision

Science.gov (United States)

Yong, Yuen Geng; Jung, Kyung Uk; Cho, Yong Beom; Yun, Seong Hyeon; Kim, Hee Cheol; Lee, Woo Yong

2012-01-01

Tubular colonic duplication presenting in adults is rare and difficult to diagnose preoperatively. Only a few cases have been reported in the literature. We report a case of a 29-year-old lady presenting with a long history of chronic constipation, abdominal mass and repeated episodes of abdominal pain. The abdominal-pelvic computed tomography scan showed segmental bowel wall thickening thought to be small bowel, and dilatation with stasis of intraluminal content. The provisional diagnosis was small bowel duplication. She was scheduled for single port laparoscopic resection. However, a T-shaped tubular colonic duplication at sigmoid colon was found intraoperatively. Resection of the large T-shaped tubular colonic duplication containing multiple impacted large fecaloma and primary anastomosis was performed. There was no perioperative complication. We report, herein, the case of a T-shaped tubular colonic duplication at sigmoid colon in an adult who was successfully treated through mini-laparotomy assisted by single port laparoscopic surgery. PMID:22403754

High-temperature, high-pressure bonding of nested tubular metallic components

International Nuclear Information System (INIS)

Quinby, T.C.

1980-01-01

This invention is a tool for effecting high-temperature, high compression bonding between the confronting faces of nested, tubular, metallic components. In a typical application, the tool is used to produce tubular target assemblies for irradiation in nuclear reactors or particle accelerators, the target assembly comprising a uranium foil and an aluminum-alloy substrate. The tool preferably is composed throughout of graphite. It comprises a tubular restraining member in which a mechanically expandable tubular core is mounted to form an annulus with the member. The components to be bonded are mounted in nested relation in the annulus. The expandable core is formed of individually movable, axially elongated segments whose outer faces cooperatively define a cylindrical pressing surface and whose inner faces cooperatively define two opposed, inwardly tapered, axial bores. Tapered rams extend respectively into the bores. The loaded tool is mounted in a conventional hot-press provided with evacuation means, heaters for maintaining its interior at bonding temperature, and hydraulic cylinders for maintaining a selected inwardly directed pressure on the tapered rams. With the hotpress evacuated and the loaded tool at the desired temperature, the cylinders are actuated to apply the selected pressure to the rams. The rams in turn expand the segmented core to maintain the nested components in compression against the restraining member. These conditions are maintained until the confronting faces of the nested components are joined in a continuous, uniform bond characterized by high thermal conductivity

Importance of early audiologic assessment in distal renal tubular acidosis

Directory of Open Access Journals (Sweden)

Elizabeth Norgett

2010-12-01

Full Text Available Anand P Swayamprakasam1, Elizabeth Stover1, Elizabeth Norgett1, Katherine G Blake-Palmer1, Michael J Cunningham2, Fiona E Karet11Department of Medical Genetics, Cambridge Institute for Medical Research, Cambridge, UK; 2Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, USAAbstract: Autosomal recessive distal renal tubular acidosis is usually a severe disease of childhood, often presenting as failure to thrive in infancy. It is often, but not always, accompanied by sensorineural hearing loss, the clinical severity and age of onset of which may be different from the other clinical features. Mutations in either ATP6V1B1 or ATP6V0A4 are the chief causes of primary distal renal tubular acidosis with or without hearing loss, although the loss is often milder in the latter. We describe a kindred with compound heterozygous alterations in ATP6V0A4, where hearing loss was formally diagnosed late in both siblings such that they missed early opportunities for hearing support. This kindred highlights the importance of routine audiologic assessments of all children with distal renal tubular acidosis, irrespective either of age at diagnosis or of which gene is mutated. In addition, when diagnostic genetic testing is undertaken, both genes should be screened irrespective of current hearing status. A strategy for this is outlined.Keywords: sensorineural hearing loss, renal tubular acidosis, recessive, genetics, mutation

High-temperature, high-pressure bonding of nested tubular metallic components

Science.gov (United States)

Quinby, T.C.

A tool is described for effecting high-temperature, high-compression bonding between the confronting faces of nested, tubular, metallic components. In a typical application, the tool is used to produce tubular target assemblies for irradiation in nuclear reactors or particle accelerators. The target assembly comprising a uranum foil and an aluninum-alloy substrate. The tool is composed of graphite. It comprises a tubular restraining member in which a mechanically expandable tubular core is mounted to form an annulus. The components to be bonded are mounted in nested relation in the annulus. The expandable core is formed of individually movable, axially elongated segments whose outer faces cooperatively define a cylindrical pressing surface and whose inner faces cooperatively define two opposed, inwardly tapered, axial bores. Tapered rams extend into the bores. The loaded tool is mounted in a conventional hot-press provided with evacuation means, heaters for maintaining its interior at bonding temperature, and hydraulic cylinders for maintaining a selected inwardly directed pressure on the tapered rams. With the hot-press evacuated and the loaded tool at the desired temperature, the cylinders are actuated to apply the selected pressure to the rams. The rams in turn expand the segmented core to maintain the nested components in compression against the restraining member. These conditions are maintained until the confronting faces of the nested components are joined in a continuous, uniform bond characterized by high thermal conductivity.

Bottom-up fabrication of artery-mimicking tubular co-cultures in collagen-based microchannel scaffolds.

Science.gov (United States)

Tan, A; Fujisawa, K; Yukawa, Y; Matsunaga, Y T

2016-10-20

We developed a robust bottom-up approach to construct open-ended, tubular co-culture constructs that simulate the human vascular morphology and microenvironment. By design, these three-dimensional artificial vessels mimic the basic architecture of an artery: a collagen-rich extracellular matrix (as the tunica externa), smooth muscle cells (SMCs) (as the tunica media), and an endothelial cell (EC) lining (as the tunica interna). A versatile needle-based fabrication technique was employed to achieve controllable arterial layouts within a PDMS-hosted collagen microchannel scaffold (330 ± 10 μm in diameter): (direct co-culture) a SMC/EC bilayer to follow the structure of an arteriole-like segment; and (encapsulated co-culture) a lateral SMC multilayer covered by an EC monolayer lining to simulate the architecture of a larger artery. Optical and fluorescence microscopy images clearly evidenced the progressive cell elongation and sprouting behavior of SMCs and ECs along the collagen gel contour and within the gel matrix under static co-culture conditions. The progressive cell growth patterns effectively led to the formation of a tubular co-culture with an internal endothelial lining expressing prominent CD31 (cluster of differentiation 31) intercellular junction markers. During a 4-day static maturation period, the artery constructs showed modest alteration in the luminal diameters (i.e. less than 10% changes from the initial measurements). This argues in favor of stable and predictable arterial architecture achieved via the proposed fabrication protocols. Both co-culture models showed a high glucose metabolic rate during the initial proliferation phase, followed by a temporary quiescent (and thus, mature) stage. These proof-of-concept models with a controllable architecture create an important foundation for advanced vessel manipulations such as the integration of relevant physiological functionality or remodeling into a vascular disease-mimicking tissue.

A stable and reproducible human blood-brain barrier model derived from hematopoietic stem cells.

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Romeo Cecchelli

Full Text Available The human blood brain barrier (BBB is a selective barrier formed by human brain endothelial cells (hBECs, which is important to ensure adequate neuronal function and protect the central nervous system (CNS from disease. The development of human in vitro BBB models is thus of utmost importance for drug discovery programs related to CNS diseases. Here, we describe a method to generate a human BBB model using cord blood-derived hematopoietic stem cells. The cells were initially differentiated into ECs followed by the induction of BBB properties by co-culture with pericytes. The brain-like endothelial cells (BLECs express tight junctions and transporters typically observed in brain endothelium and maintain expression of most in vivo BBB properties for at least 20 days. The model is very reproducible since it can be generated from stem cells isolated from different donors and in different laboratories, and could be used to predict CNS distribution of compounds in human. Finally, we provide evidence that Wnt/β-catenin signaling pathway mediates in part the BBB inductive properties of pericytes.

Selective Cannabinoid 2 Receptor Stimulation Reduces Tubular Epithelial Cell Damage after Renal Ischemia-Reperfusion Injury.

Science.gov (United States)

Pressly, Jeffrey D; Mustafa, Suni M; Adibi, Ammaar H; Alghamdi, Sahar; Pandey, Pankaj; Roy, Kuldeep K; Doerksen, Robert J; Moore, Bob M; Park, Frank

2018-02-01

Ischemia-reperfusion injury (IRI) is a common cause of acute kidney injury (AKI), which is an increasing problem in the clinic and has been associated with elevated rates of mortality. Therapies to treat AKI are currently not available, so identification of new targets that can be modulated to ameliorate renal damage upon diagnosis of AKI is essential. In this study, a novel cannabinoid receptor 2 (CB2) agonist, SMM-295 [3'-methyl-4-(2-(thiophen-2-yl)propan-2-yl)biphenyl-2,6-diol], was designed, synthesized, and tested in vitro and in silico. Molecular docking of SMM-295 into a CB2 active-state homology model showed that SMM-295 interacts well with key amino acids to stabilize the active state. In human embryonic kidney 293 cells, SMM-295 was capable of reducing cAMP production with 66-fold selectivity for CB2 versus cannabinoid receptor 1 and dose-dependently increased mitogen-activated protein kinase and Akt phosphorylation. In vivo testing of the CB2 agonist was performed using a mouse model of bilateral IRI, which is a common model to mimic human AKI, where SMM-295 was immediately administered upon reperfusion of the kidneys after the ischemia episode. Histologic damage assessment 48 hours after reperfusion demonstrated reduced tubular damage in the presence of SMM-295. This was consistent with reduced plasma markers of renal dysfunction (i.e., creatinine and neutrophil gelatinase-associated lipocalin) in SMM-295-treated mice. Mechanistically, kidneys treated with SMM-295 were shown to have elevated activation of Akt with reduced terminal deoxynucleotidyl transferase-mediated digoxigenin-deoxyuridine nick-end labeling (TUNEL)-positive cells compared with vehicle-treated kidneys after IRI. These data suggest that selective CB2 receptor activation could be a potential therapeutic target in the treatment of AKI. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Transporter-Guided Delivery of Nanoparticles to Improve Drug Permeation across Cellular Barriers and Drug Exposure to Selective Cell Types

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Longfa Kou

2018-01-01

Full Text Available Targeted nano-drug delivery systems conjugated with specific ligands to target selective cell-surface receptors or transporters could enhance the efficacy of drug delivery and therapy. Transporters are expressed differentially on the cell-surface of different cell types, and also specific transporters are expressed at higher than normal levels in selective cell types under pathological conditions. They also play a key role in intestinal absorption, delivery via non-oral routes (e.g., pulmonary route and nasal route, and transfer across biological barriers (e.g., blood–brain barrier and blood–retinal barrier. As such, the cell-surface transporters represent ideal targets for nano-drug delivery systems to facilitate drug delivery to selective cell types under normal or pathological conditions and also to avoid off-target adverse side effects of the drugs. There is increasing evidence in recent years supporting the utility of cell-surface transporters in the field of nano-drug delivery to increase oral bioavailability, to improve transfer across the blood–brain barrier, and to enhance delivery of therapeutics in a cell-type selective manner in disease states. Here we provide a comprehensive review of recent advancements in this interesting and important area. We also highlight certain key aspects that need to be taken into account for optimal development of transporter-assisted nano-drug delivery systems.

MiR-30c regulates cisplatin-induced apoptosis of renal tubular epithelial cells by targeting Bnip3L and Hspa5.

Science.gov (United States)

Du, Bin; Dai, Xiao-Meng; Li, Shuang; Qi, Guo-Long; Cao, Guang-Xu; Zhong, Ying; Yin, Pei-di; Yang, Xue-Song

2017-08-10

As a common anticancer drug, cisplatin has been widely used for treating tumors in the clinic. However, its side effects, especially its nephrotoxicity, noticeably restrict the application of cisplatin. Therefore, it is imperative to investigate the mechanism of renal injury and explore the corresponding remedies. In this study, we showed the phenotypes of the renal tubules and epithelial cell death as well as elevated cleaved-caspase3- and TUNEL-positive cells in rats intraperitoneally injected with cisplatin. Similar cisplatin-induced cell apoptosis was found in HK-2 and NRK-52E cells exposed to cisplatin as well. In both models of cisplatin-induced apoptosis in vivo and in vitro, quantitative PCR data displayed reductions in miR-30a-e expression levels, indicating that miR-30 might be involved in regulating cisplatin-induced cell apoptosis. This was further confirmed when the effects of cisplatin-induced cell apoptosis were found to be closely correlated with alterations in miR-30c expression, which were manipulated by transfection of either the miR-30c mimic or miR-30c inhibitor in HK-2 and NRK-52E cells. Using bioinformatics tools, including TargetScan and a gene expression database (Gene Expression Omnibus), Adrb1, Bnip3L, Hspa5 and MAP3K12 were predicted to be putative target genes of miR-30c in cisplatin-induced apoptosis. Subsequently, Bnip3L and Hspa5 were confirmed to be the target genes after determining the expression of these putative genes following manipulation of miR-30c expression levels in HK-2 cells. Taken together, our current experiments reveal that miR-30c is certainly involved in regulating the renal tubular cell apoptosis induced by cisplatin, which might supply a new strategy to minimize cisplatin-induced nephrotoxicity.

Tubular closure mechanism

International Nuclear Information System (INIS)

Kalen, D.D.; Mitchem, J.W.

1982-01-01

This invention relates to a closure mechanism for tubular irradiation surveillance specimen assembly holder used in nuclear reactors. The closure mechanism is composed of a latching member which includes a generally circular chamber with a plurality of elongated latches depending therefrom. The latching member circumscribes part of an actuator member which is disposed within the latching member so as to be axially movable. The axial movement of the actuator actuates positioning of the latches between positions in which the latches are locked and secured within the actuator member. Means, capable of being remotely manipulated, are provided to move the actuator in order to position the latches and load the articles within the tube

The Tubular Penetration Depth and Adaption of Four Sealers: A Scanning Electron Microscopic Study

Directory of Open Access Journals (Sweden)

Huan Chen

2017-01-01

Full Text Available Background. The tubular penetration and adaptation of the sealer are important factors for successful root canal filling. The aim of this study was to evaluate the tubular penetration depth of four different sealers in the coronal, middle, and apical third of root canals as well as the adaptation of these sealers to root canal walls. Materials and Methods. 50 single-rooted teeth were prepared in this study. Forty-eight of them were filled with different sealers (Cortisomol, iRoot SP, AH-Plus, and RealSeal SE and respective core filling materials. Then the specimens were sectioned and scanning electron microscopy was employed to assess the tubular penetration and adaptation of the sealers. Results. Our results demonstrated that the maximum penetration was exhibited by RealSeal SE, followed by AH-Plus, iRoot SP, and Cortisomol. As regards the adaptation property to root canal walls, AH-Plus has best adaptation capacity followed by iRoot SP, RealSeal SE, and Cortisomol. Conclusion. The tubular penetration and adaptation vary with the different sealers investigated. RealSeal SE showed the most optimal tubular penetration, whereas AH-Plus presented the best adaptation to the root canal walls.

Identification of genomic biomarkers for concurrent diagnosis of drug-induced renal tubular injury using a large-scale toxicogenomics database

International Nuclear Information System (INIS)

Kondo, Chiaki; Minowa, Yohsuke; Uehara, Takeki; Okuno, Yasushi; Nakatsu, Noriyuki; Ono, Atsushi; Maruyama, Toshiyuki; Kato, Ikuo; Yamate, Jyoji; Yamada, Hiroshi; Ohno, Yasuo; Urushidani, Tetsuro

2009-01-01

Drug-induced renal tubular injury is one of the major concerns in preclinical safety evaluations. Toxicogenomics is becoming a generally accepted approach for identifying chemicals with potential safety problems. In the present study, we analyzed 33 nephrotoxicants and 8 non-nephrotoxic hepatotoxicants to elucidate time- and dose-dependent global gene expression changes associated with proximal tubular toxicity. The compounds were administered orally or intravenously once daily to male Sprague-Dawley rats. The animals were exposed to four different doses of the compounds, and kidney tissues were collected on days 4, 8, 15, and 29. Gene expression profiles were generated from kidney RNA by using Affymetrix GeneChips and analyzed in conjunction with the histopathological changes. We used the filter-type gene selection algorithm based on t-statistics conjugated with the SVM classifier, and achieved a sensitivity of 90% with a selectivity of 90%. Then, 92 genes were extracted as the genomic biomarker candidates that were used to construct the classifier. The gene list contains well-known biomarkers, such as Kidney injury molecule 1, Ceruloplasmin, Clusterin, Tissue inhibitor of metallopeptidase 1, and also novel biomarker candidates. Most of the genes involved in tissue remodeling, the immune/inflammatory response, cell adhesion/proliferation/migration, and metabolism were predominantly up-regulated. Down-regulated genes participated in cell adhesion/proliferation/migration, membrane transport, and signal transduction. Our classifier has better prediction accuracy than any of the well-known biomarkers. Therefore, the toxicogenomics approach would be useful for concurrent diagnosis of renal tubular injury.

Regulation of Thrombin-Induced Lung Endothelial Cell Barrier Disruption by Protein Kinase C Delta.

Directory of Open Access Journals (Sweden)

Lishi Xie

Full Text Available Protein Kinase C (PKC plays a significant role in thrombin-induced loss of endothelial cell (EC barrier integrity; however, the existence of more than 10 isozymes of PKC and tissue-specific isoform expression has limited our understanding of this important second messenger in vascular homeostasis. In this study, we show that PKCδ isoform promotes thrombin-induced loss of human pulmonary artery EC barrier integrity, findings substantiated by PKCδ inhibitory studies (rottlerin, dominant negative PKCδ construct and PKCδ silencing (siRNA. In addition, we identified PKCδ as a signaling mediator upstream of both thrombin-induced MLC phosphorylation and Rho GTPase activation affecting stress fiber formation, cell contraction and loss of EC barrier integrity. Our inhibitor-based studies indicate that thrombin-induced PKCδ activation exerts a positive feedback on Rho GTPase activation and contributes to Rac1 GTPase inhibition. Moreover, PKD (or PKCμ and CPI-17, two known PKCδ targets, were found to be activated by PKCδ in EC and served as modulators of cytoskeleton rearrangement. These studies clarify the role of PKCδ in EC cytoskeleton regulation, and highlight PKCδ as a therapeutic target in inflammatory lung disorders, characterized by the loss of barrier integrity, such as acute lung injury and sepsis.

Type 2 innate lymphoid cells disrupt bronchial epithelial barrier integrity by targeting tight junctions through IL-13 in asthmatic patients.

Science.gov (United States)

Sugita, Kazunari; Steer, Catherine A; Martinez-Gonzalez, Itziar; Altunbulakli, Can; Morita, Hideaki; Castro-Giner, Francesc; Kubo, Terufumi; Wawrzyniak, Paulina; Rückert, Beate; Sudo, Katsuko; Nakae, Susumu; Matsumoto, Kenji; O'Mahony, Liam; Akdis, Mübeccel; Takei, Fumio; Akdis, Cezmi A

2018-01-01

Bronchial epithelial barrier leakiness and type 2 innate lymphoid cells (ILC2s) have been separately linked to asthma pathogenesis; however, the influence of ILC2s on the bronchial epithelial barrier has not been investigated previously. We investigated the role of ILC2s in the regulation of bronchial epithelial tight junctions (TJs) and barrier function both in bronchial epithelial cells of asthmatic patients and healthy subjects and general innate lymphoid cell- and ILC2-deficient mice. Cocultures of human ILC2s and bronchial epithelial cells were used to determine transepithelial electrical resistance, paracellular flux, and TJ mRNA and protein expressions. The effect of ILC2s on TJs was examined by using a murine model of IL-33-induced airway inflammation in wild-type, recombination-activating gene 2 (Rag2) -/- , Rag2 -/- Il2rg -/- , and Rora sg/sg mice undergoing bone marrow transplantation to analyze the in vivo relevance of barrier disruption by ILC2s. ILC2s significantly impaired the epithelial barrier, as demonstrated by reduced transepithelial electrical resistance and increased fluorescein isothiocyanate-dextran permeability in air-liquid interface cultures of human bronchial epithelial cells. This was in parallel to decreased mRNAs and disrupted protein expression of TJ proteins and was restored by neutralization of IL-13. Intranasal administration of recombinant IL-33 to wild-type and Rag2 -/- mice lacking T and B cells triggered TJ disruption, whereas Rag2 -/- Il2rg -/- and Rora sg/sg mice undergoing bone marrow transplantation that lack ILC2s did not show any barrier leakiness. Direct nasal administration of IL-13 was sufficient to induce deficiency in the TJ barrier in the bronchial epithelium of mice in vivo. These data highlight an essential mechanism in asthma pathogenesis by demonstrating that ILC2s are responsible for bronchial epithelial TJ barrier leakiness through IL-13. Copyright © 2017 American Academy of Allergy, Asthma & Immunology

Polydopamine-coated open tubular column for the separation of proteins by capillary electrochromatography.

Science.gov (United States)

Xiao, Xing; Wang, Wentao; Chen, Jia; Jia, Li

2015-08-01

The separation and determination of proteins in food is an important aspect in food industry. Inspired by the self-polymerization of dopamine under alkaline conditions and the natural adhesive properties of polydopamine, in this paper, a simple and economical method was developed for the preparation of polydopamine-coated open tubular column, in which ammonium persulfate was used as the source of oxygen to induce and facilitate the polymerization of dopamine to form polydopamine. In comparison with a naked fused-silica capillary, the direction and magnitude of the electro-osmotic flow of the as-prepared polydopamine-coated open tubular column could be manipulated by varying the pH values of background solutions due to the existence of amine and phenolic hydroxyl groups on polydopamine coating. The surface morphology of the polydopamine-coated open tubular column was studied by scanning electron microscopy, and the thickness of polydopamine coating was 106 nm. The performance of the polydopamine-coated open tubular column was validated by analysis of proteins. The relative standard deviations of migration times of proteins representing run-to-run, day-to-day, and column-to-column were less than 3.5%. In addition, the feasibility of the polydopamine-coated open tubular column for real samples was verified by the separation of proteins in chicken egg white and pure milk. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of the Velocity and Pressure Drop in a Tubular Type Fuel

International Nuclear Information System (INIS)

Jonghark Park; Heetaek Chae; Cheol Park; Heonil Kim

2006-01-01

We have developed a tubular type fuel assembly design as one of candidates for fuel to be used in the Advanced HANARO Reactor (AHR). The tubular type fuel has several merits over a rod type fuel with respect to the thermal-hydraulic and structural safety; the larger ratio of surface area to volume makes the surface temperature of a fuel element become lower, and curved plate is stronger against longitudinal bending and vibration. In the other side, a disadvantage is expected such that the flow velocity can be distributed unevenly channel by channel because the flow channels are isolated from each other in a tubular type fuel assembly. In addition to the design development, we also investigated the flow characteristics of the tubular fuel experimentally. To examine the flow velocity distribution and pressure drop, we made an experiment facility and a mockup of the tubular fuel assembly. The fuel assembly consists of 6 concentric fuel tubes so that 7 layers are made between fuel tubes. Since each layer is divided into three sections by stiffeners, 21 isolated flow channels are made in total. We employed pitot-tubes to measure the coolant velocity in each channel. The maximum velocity was measured as large as about 28% of the average velocity. It was observed in the innermost channel contrarily to the expectation from the hydraulic diameter. A change in the total flow rate did not affect the flow distribution. Meanwhile, the pressure drop was measured as about 70% of the drop in the rod type fuel assembly in use in HANARO. (authors)

Genetics Home Reference: renal tubular acidosis with deafness

Science.gov (United States)

... adults with renal tubular acidosis with deafness have short stature, and many develop kidney stones. The metabolic acidosis ... enlarged vestibular aqueduct, can be seen with medical imaging. The vestibular aqueduct is a bony canal that ...

Potential Strategies to Address the Major Clinical Barriers Facing Stem Cell Regenerative Therapy for Cardiovascular Disease: A Review.

Science.gov (United States)

Nguyen, Patricia K; Neofytou, Evgenios; Rhee, June-Wha; Wu, Joseph C

2016-11-01

Although progress continues to be made in the field of stem cell regenerative medicine for the treatment of cardiovascular disease, significant barriers to clinical implementation still exist. To summarize the current barriers to the clinical implementation of stem cell therapy in patients with cardiovascular disease and to discuss potential strategies to overcome them. Information for this review was obtained through a search of PubMed and the Cochrane database for English-language studies published between January 1, 2000, and July 25, 2016. Ten randomized clinical trials and 8 systematic reviews were included. One of the major clinical barriers facing the routine implementation of stem cell therapy in patients with cardiovascular disease is the limited and inconsistent benefit observed thus far. Reasons for this finding are unclear but may be owing to poor cell retention and survival, as suggested by numerous preclinical studies and a small number of human studies incorporating imaging to determine cell fate. Additional studies in humans using imaging to determine cell fate are needed to understand how these factors contribute to the limited efficacy of stem cell therapy. Treatment strategies to address poor cell retention and survival are under investigation and include the following: coadministration of immunosuppressive and prosurvival agents, delivery of cardioprotective factors packaged in exosomes rather than the cells themselves, and use of tissue-engineering strategies to provide structural support for cells. If larger grafts are achieved using these strategies, it will be imperative to carefully monitor for the potential risks of tumorigenicity, immunogenicity, and arrhythmogenicity. Despite important achievements to date, stem cell therapy is not yet ready for routine clinical implementation. Significant research is still needed to address the clinical barriers outlined herein before the next wave of large clinical trials is under way.

Nano-tubular cellulose for bioprocess technology development.

Science.gov (United States)

Koutinas, Athanasios A; Sypsas, Vasilios; Kandylis, Panagiotis; Michelis, Andreas; Bekatorou, Argyro; Kourkoutas, Yiannis; Kordulis, Christos; Lycourghiotis, Alexis; Banat, Ibrahim M; Nigam, Poonam; Marchant, Roger; Giannouli, Myrsini; Yianoulis, Panagiotis

2012-01-01

Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, which was done by SEM, porosimetry and X-ray powder diffractometry. The results showed that the structure of nano-tubular cellulose (NC) justifies its suitability for use in "cold pasteurization" processes and its promoting activity in bioprocessing (fermentation). The last was explained by a glucose pump theory. Also, it was demonstrated that crystallization of viscous invert sugar solutions during freeze drying could not be otherwise achieved unless NC was present. This effect as well as the feasibility of extremely low temperature fermentation are due to reduction of the activation energy, and have facilitated the development of technologies such as wine fermentations at home scale (in a domestic refrigerator). Moreover, NC may lead to new perspectives in research such as the development of new composites, templates for cylindrical nano-particles, etc.

Performance improvement of the circular tubular PEMFC by using different architectures and number of layers

International Nuclear Information System (INIS)

Mohammadi-Ahmar, Akbar; Osanloo, Behzad; Solati, Ali; Ghasemi, Jalal

2016-01-01

Highlights: • A full three-dimensional model was developed for cylindrical PEMFC. • CFD study on reactants distribution, current density and final power was performed. • Five cylindrical configurations were investigated (CP, C2C, C4C, C6C and C8C). - Abstract: The effects of arrangement and number of Membrane, Catalyst layer (CL) and Gas Diffusion layer (GDL) is investigated in present study. A full three-dimensional model was developed for tubular shaped PEMFC and the distribution of reactant concentration along anode and cathode channels, current density, power consumption and production were studied through computational Fluid dynamics (CFD). In order to do so, five arrangements of the tubular-shaped PEMFC namely: circular peripheral (CP), circular with two channels (C2C), circular with four channels (C4C), circular with six channels (C6C) and circular with eight channels (C8C) are presented. Comparison was made for new arrangements of layers, for the same active area and input mass flow in the anode and cathode. The results of polarization curve and power density shows that via increasing the number of layers, and thereby reducing the length of the fuel cell, more reactants are consumed along the tubular-shaped PEMFC. Among the five new arrangements, the CP case due to having high flow velocity for the same flow rate, has lower consumption along the channel and demonstrates undesirable results. Also in the dual-channel case (C2C) the core of the reacting flow is far from the reaction location (i.e. CL) therefor showed the lowest consumption and thus lowest power density. Whereas the eight-channel (C8C) configuration because of the appropriate distance between Membrane, CL and GDL layers and the core of the flow, increases the power output and reduces the cost, simultaneously due to shortest length in comparison to other cases. The results of present study can be employed for the manufacturing of new tubular-shaped PEMFC.

A class of dynamin-like GTPases involved in the generation of the tubular ER network

Science.gov (United States)

Hu, Junjie; Shibata, Yoko; Zhu, Peng-Peng; Voss, Christiane; Rismanchi, Neggy; Prinz, William A.; Rapoport, Tom A.; Blackstone, Craig

2009-01-01

The endoplasmic reticulum (ER) consists of tubules that are shaped by the reticulons and DP1/Yop1p, but how the tubules form an interconnected network is unknown. Here, we show that mammalian atlastins, which are dynamin-like, integral membrane GTPases, interact with the tubule-shaping proteins. The atlastins localize to the tubular ER and are required for proper network formation in vivo and in vitro. Depletion of the atlastins or overexpression of dominant-negative forms inhibits tubule interconnections. The Sey1p GTPase in S. cerevisiae is likely a functional ortholog of the atlastins; it shares the same signature motifs and membrane topology and interacts genetically and physically with the tubule-shaping proteins. Cells simultaneously lacking Sey1p and a tubule-shaping protein have ER morphology defects. These results indicate that formation of the tubular ER network depends on conserved dynamin-like GTPases. Since atlastin-1 mutations cause a common form of hereditary spastic paraplegia, we suggest ER shaping defects as a novel neuropathogenic mechanism. PMID:19665976

Downregulation of the S1P Transporter Spinster Homology Protein 2 (Spns2 Exerts an Anti-Fibrotic and Anti-Inflammatory Effect in Human Renal Proximal Tubular Epithelial Cells

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Olivier Blanchard

2018-05-01

Full Text Available Sphingosine kinase (SK catalyses the formation of sphingosine 1-phosphate (S1P, which acts as a key regulator of inflammatory and fibrotic reactions, mainly via S1P receptor activation. Here, we show that in the human renal proximal tubular epithelial cell line HK2, the profibrotic mediator transforming growth factor β (TGFβ induces SK-1 mRNA and protein expression, and in parallel, it also upregulates the expression of the fibrotic markers connective tissue growth factor (CTGF and fibronectin. Stable downregulation of SK-1 by RNAi resulted in the increased expression of CTGF, suggesting a suppressive effect of SK-1-derived intracellular S1P in the fibrotic process, which is lost when SK-1 is downregulated. In a further approach, the S1P transporter Spns2, which is known to export S1P and thereby reduces intracellular S1P levels, was stably downregulated in HK2 cells by RNAi. This treatment decreased TGFβ-induced CTGF and fibronectin expression, and it abolished the strong induction of the monocyte chemotactic protein 1 (MCP-1 by the pro-inflammatory cytokines tumor necrosis factor (TNFα and interleukin (IL-1β. Moreover, it enhanced the expression of aquaporin 1, which is an important water channel that is expressed in the proximal tubules, and reverted aquaporin 1 downregulation induced by IL-1β/TNFα. On the other hand, overexpression of a Spns2-GFP construct increased S1P secretion and it resulted in enhanced TGFβ-induced CTGF expression. In summary, our data demonstrate that in human renal proximal tubular epithelial cells, SK-1 downregulation accelerates an inflammatory and fibrotic reaction, whereas Spns2 downregulation has an opposite effect. We conclude that Spns2 represents a promising new target for the treatment of tubulointerstitial inflammation and fibrosis.

Na effect on flexible Cu(In,Ga)Se{sub 2} photovoltaic cell depending on diffusion barriers (SiOx, i-ZnO) on stainless steel

Energy Technology Data Exchange (ETDEWEB)

Lee, Woo-Jung; Cho, Dae-Hyung; Wi, Jae-Hyung; Han, Won Seok [Electronics and Telecommunications Research Institute, Daejeon 305-700 (Korea, Republic of); Kim, Jeha [Insitute of Photovoltaics, Cheongju University, Cheongju 360-764 (Korea, Republic of); Chung, Yong-Duck, E-mail: ydchung@etri.re.kr [Electronics and Telecommunications Research Institute, Daejeon 305-700 (Korea, Republic of); Department of Advanced Device Engineering, Korea University of Science and Technology, Daejeon 305-350 (Korea, Republic of)

2014-10-15

Cu(In,Ga)Se{sub 2} (CIGS) based-photovoltaic (PV) cells with different diffusion barriers of SiOx and i-ZnO were fabricated on stainless steel (STS) substrate and their electrical characteristics were investigated by measuring J–V curves under illuminated and dark conditions. The physical properties of the CIGS film depending on type of diffusion barrier were also analyzed using X-ray diffraction and secondary ion mass spectroscopy. The efficiency of the CIGS-PV cell with i-ZnO barrier was approximately 2% higher than that with the SiOx barrier. Through the analysis of dark J–V curves, we discovered that distinctive defects were formed in the band gap of CIGS based on which diffusion barrier contacted the STS. The diffraction pattern showed a slightly different tendency of the peak intensity ratio of (220/204)/(112) in the PV cell with the i-ZnO barrier, which was slightly higher than that in the PV cell with SiOx barrier. In elemental depth profile, a deficient Ga profile was observed near the surface of the CIGS film with the SiOx barrier, and an abundant Na profile within the CIGS film with the i-ZnO barrier was detected. This is attributed to a difference in thermal conduction through the diffusion barriers during CIGS film growth, originating from the larger thermal conductivity of ZnO compared with SiOx. - Highlights: • We fabricated CIGS-PV cells with diffusion barriers of SiOx and i-ZnO on STS. • The efficiency of CIGS-PV cell with i-ZnO was ∼2% higher than that with SiOx. • Distinctive defects were formed into CIGS absorber depending on diffusion barrier.

Transforming growth factor-β-sphingosine kinase 1/S1P signaling upregulates microRNA-21 to promote fibrosis in renal tubular epithelial cells.

Science.gov (United States)

Liu, Xiujuan; Hong, Quan; Wang, Zhen; Yu, Yanyan; Zou, Xin; Xu, Lihong

2016-02-01

Renal fibrosis is a progressive pathological change characterized by tubular cell apoptosis, tubulointerstitial fibroblast proliferation, and excessive deposition of extracellular matrix (ECM). miR-21 has been implicated in transforming growth factor-β (TGF-β)-stimulated tissue fibrosis. Recent studies showed that sphingosine kinase/sphingosine-1-phosphate (SphK/S1P) are also critical for TGF-β-stimulated tissue fibrosis; however, it is not clear whether SphK/S1P interacts with miR-21 or not. In this study, we hypothesized that SphK/S1P signaling is linked to upregulation of miR-21 by TGF-β. To verify this hypothesis, we first determined that miR-21 was highly expressed in renal tubular epithelial cells (TECs) stimulated with TGF-β by using qRT-PCR and Northern blotting. Simultaneously, inhibition of miR-21, mediated by the corresponding antimir, markedly decreased the expression and deposition of type I collagen, fibronectin (Fn), cysteine-rich protein 61 (CCN1), α-smooth muscle actin, and fibroblast-specific protein1 in TGF-β-treated TECs. ELISA and qRT-PCR were used to measure the S1P and SphK1 levels in TECs. S1P production was induced by TGF-β through activation of SphK1. Furthermore, it was observed that TGF-β-stimulated upregulation of miR-21 was abolished by SphK1 siRNA and was restored by the addition of exogenous S1P. Blocking S1PR2 also inhibited upregulation of miR-21. Additionally, miR-21 overexpression attenuated the repression of TGF-β-stimulated ECM deposition and epithelial-mesenchymal transition by SphK1 and S1PR2 siRNA. In summary, our study demonstrates a link between SphK1/S1P and TGF-β-induced miR-21 in renal TECs and may represent a novel therapeutic target in renal fibrosis. © 2015 by the Society for Experimental Biology and Medicine.

Muscle imaging in patients with tubular aggregate myopathy caused by mutations in STIM1

DEFF Research Database (Denmark)

Tasca, Giorgio; D'Amico, Adele; Monforte, Mauro

2015-01-01

Tubular aggregate myopathy is a genetically heterogeneous disease characterized by tubular aggregates as the hallmark on muscle biopsy. Mutations in STIM1 have recently been identified as one genetic cause in a number of tubular aggregate myopathy cases. To characterize the pattern of muscle...... involvement in this disease, upper and lower girdles and lower limbs were imaged in five patients with mutations in STIM1, and the scans were compared with two patients with tubular aggregate myopathy not caused by mutations in STIM1. A common pattern of involvement was found in STIM1-mutated patients...... of thigh and posterior leg with sparing of gracilis, tibialis anterior and, to a lesser extent, short head of biceps femoris. Mutations in STIM1 are associated with a homogeneous involvement on imaging despite variable clinical features. Muscle imaging can be useful in identifying STIM1-mutated patients...

The addition of red lead to flat plate and tubular valve regulated miners cap lamp lead-acid batteries

Energy Technology Data Exchange (ETDEWEB)

Ferg, E.E.; Loyson, P. [Department of Chemistry, Nelson Mandela Metropolitan University, P.O. Box 77000, Port Elizabeth 6031 (South Africa); Poorun, A. [Willard Batteries, P.O. Box 1844, Port Elizabeth 6000 (South Africa)

2006-04-21

The study looked at the use of red lead in the manufacturing of valve regulated lead acid (VRLA) miners cap lamp (MCL) batteries that were made with either flat plate or tubular positive electrodes. A problem with using only grey oxide in the manufacture of thick flat plate or tubular electrodes is the poor conversion of the active material to the desired lead dioxide. The addition of red lead to the initial starting material improves the formation efficiency but is considerably more expensive thereby increasing the cost of manufacturing. The study showed that by carefully controlling the formation conditions in terms of the voltage and temperature of a battery, good capacity performance can be achieved for cells made with flat plate electrodes that contain up to 25% red lead. The small amount of red lead in the active cured material reduces the effect of electrode surface sulphate formation and allows the battery to achieve its rated capacity within the first few cycles. Batteries made with flat plate positive electrodes that contained more that 50% red lead showed good initial capacity but had poor structural active material bonding. The study showed that MCL batteries made with tubular positive electrodes that contained less than 75% red lead resulted in a poorly formed electrode with limited capacity utilization. Pickling and soaking times of the tubular electrodes should be kept at a minimum thereby allowing higher active material utilization during subsequent capacity cycling. The study further showed that it is beneficial to use higher formation rates in order to reduce manufacturing time and to improve the active material characteristics. (author)

Effective transvascular delivery of nanoparticles across the blood-brain tumor barrier into malignant glioma cells

Directory of Open Access Journals (Sweden)

Sharma Kamal

2008-12-01

Full Text Available Abstract Background Effective transvascular delivery of nanoparticle-based chemotherapeutics across the blood-brain tumor barrier of malignant gliomas remains a challenge. This is due to our limited understanding of nanoparticle properties in relation to the physiologic size of pores within the blood-brain tumor barrier. Polyamidoamine dendrimers are particularly small multigenerational nanoparticles with uniform sizes within each generation. Dendrimer sizes increase by only 1 to 2 nm with each successive generation. Using functionalized polyamidoamine dendrimer generations 1 through 8, we investigated how nanoparticle size influences particle accumulation within malignant glioma cells. Methods Magnetic resonance and fluorescence imaging probes were conjugated to the dendrimer terminal amines. Functionalized dendrimers were administered intravenously to rodents with orthotopically grown malignant gliomas. Transvascular transport and accumulation of the nanoparticles in brain tumor tissue was measured in vivo with dynamic contrast-enhanced magnetic resonance imaging. Localization of the nanoparticles within glioma cells was confirmed ex vivo with fluorescence imaging. Results We found that the intravenously administered functionalized dendrimers less than approximately 11.7 to 11.9 nm in diameter were able to traverse pores of the blood-brain tumor barrier of RG-2 malignant gliomas, while larger ones could not. Of the permeable functionalized dendrimer generations, those that possessed long blood half-lives could accumulate within glioma cells. Conclusion The therapeutically relevant upper limit of blood-brain tumor barrier pore size is approximately 11.7 to 11.9 nm. Therefore, effective transvascular drug delivery into malignant glioma cells can be accomplished by using nanoparticles that are smaller than 11.7 to 11.9 nm in diameter and possess long blood half-lives.

Three-Dimensional Tubular MoS2/PANI Hybrid Electrode for High Rate Performance Supercapacitor.

Science.gov (United States)

Ren, Lijun; Zhang, Gaini; Yan, Zhe; Kang, Liping; Xu, Hua; Shi, Feng; Lei, Zhibin; Liu, Zong-Huai

2015-12-30

By using three-dimensional (3D) tubular molybdenum disulfide (MoS2) as both an active material in electrochemical reaction and a framework to provide more paths for insertion and extraction of ions, PANI nanowire arrays with a diameter of 10-20 nm can be controllably grown on both the external and internal surface of 3D tubular MoS2 by in situ oxidative polymerization of aniline monomers and 3D tubular MoS2/PANI hybrid materials with different amounts of PANI are prepared. A controllable growth of PANI nanowire arrays on the tubular MoS2 surface provides an opportunity to optimize the capacitive performance of the obtained electrodes. When the loading amount of PANI is 60%, the obtained MoS2/PANI-60 hybrid electrode not only shows a high specific capacitance of 552 F/g at a current density of 0.5 A/g, but also gives excellent rate capability of 82% from 0.5 to 30 A/g. The remarkable rate performance can be mainly attributed to the architecture with synergistic effect between 3D tubular MoS2 and PANI nanowire arrays. Moreover, the MoS2/PANI-60 based symmetric supercapacitor also exhibits the excellent rate performance and good cycling stability. The specific capacitance based on the total mass of the two electrodes is 124 F/g at a current density of 1 A/g and 79% of its initial capacitance is remained after 6000 cycles. The 3D tubular structure provides a good and favorable method for improving the capacitance retention of PANI electrode.

Modelling the endothelial blood-CNS barriers: a method for the production of robust in vitro models of the rat blood-brain barrier and blood-spinal cord barrier.

Science.gov (United States)

Watson, P Marc D; Paterson, Judy C; Thom, George; Ginman, Ulrika; Lundquist, Stefan; Webster, Carl I

2013-06-18

Modelling the blood-CNS barriers of the brain and spinal cord in vitro continues to provide a considerable challenge for research studying the passage of large and small molecules in and out of the central nervous system, both within the context of basic biology and for pharmaceutical drug discovery. Although there has been considerable success over the previous two decades in establishing useful in vitro primary endothelial cell cultures from the blood-CNS barriers, no model fully mimics the high electrical resistance, low paracellular permeability and selective influx/efflux characteristics of the in vivo situation. Furthermore, such primary-derived cultures are typically labour-intensive and generate low yields of cells, limiting scope for experimental work. We thus aimed to establish protocols for the high yield isolation and culture of endothelial cells from both rat brain and spinal cord. Our aim was to optimise in vitro conditions for inducing phenotypic characteristics in these cells that were reminiscent of the in vivo situation, such that they developed into tight endothelial barriers suitable for performing investigative biology and permeability studies. Brain and spinal cord tissue was taken from the same rats and used to specifically isolate endothelial cells to reconstitute as in vitro blood-CNS barrier models. Isolated endothelial cells were cultured to expand the cellular yield and then passaged onto cell culture inserts for further investigation. Cell culture conditions were optimised using commercially available reagents and the resulting barrier-forming endothelial monolayers were characterised by functional permeability experiments and in vitro phenotyping by immunocytochemistry and western blotting. Using a combination of modified handling techniques and cell culture conditions, we have established and optimised a protocol for the in vitro culture of brain and, for the first time in rat, spinal cord endothelial cells. High yields of both CNS

Design and fabrication of a nanofibrous polycaprolactone tubular nerve guide for peripheral nerve tissue engineering using a two-pole electrospinning system

International Nuclear Information System (INIS)

Panahi-Joo, Y; Abd-Emami, B; Bonakdar, S; Karkhaneh, A; Nourinia, A; Negahdari, B; Renaud, P

2016-01-01

Nerve guidance conduits are considered to be the new generation of scaffolds designed for nerve disorders. A tubular construct with a highly aligned fibrous structure, mimicking the endoneurium layer surrounding inner axons of a nerve fascicle, is a suitable candidate for a nerve guide. In this paper a new approach for the fabrication of 3D tubular nerve guides is introduced using simulation of a two-pole electrospinning system and describing its mechanism. The structure of this scaffold is then optimized using the Taguchi statistical method and after morphological studies by scanning electron microscopy, the crystallinity, tensile strength and protein adsorption of these highly aligned fibres are investigated, comparing them with semi-aligned and random fibres produced via conventional mandrel electrospinning. Cell attachment, proliferation and migration of PC12 neuronal like cells are studied on highly aligned, semi aligned and random structures, and morphological change and elongation are observed in PC12 cells. The results of these studies suggest that conduits fabricated using two-pole electrospinning are a suitable and promising scaffold for peripheral and even spinal nerve regeneration. This nerve guide has a great potential for further advanced modifications and regeneration in higher levels. (paper)

In-Situ TEM-STM Observations of SWCNT Ropes/Tubular Transformations

Science.gov (United States)

Sola, F.; Lebron-Colon, M.; Ferreira, P. J.; Fonseca, L. F.; Meador, M. A.; Marin, C.

2010-01-01

Single-walled carbon nanotubes (SWCNTs) prepared by the HiPco process were purified using a modified gas phase purification technique. A TEM-STM holder was used to study the morphological changes of SWCNT ropes as a function of applied voltage. Kink formation, buckling behavior, tubular transformation and eventual breakdown of the system were observed. The tubular formation was attributed to a transformation from SWCNT ropes to multi-walled carbon nanotube (MWCNT) structures. It is likely mediated by the patching and tearing mechanism which is promoted primarily by the mobile vacancies generated due to current-induced heating and, to some extent, by electron irradiation.

78 FR 77421 - Certain Oil Country Tubular Goods From India: Preliminary Affirmative Countervailing Duty...

Science.gov (United States)

2013-12-23

..., Saudi Arabia, Taiwan, Thailand, the Republic of Turkey, Ukraine, and the Socialist Republic of Vietnam... DEPARTMENT OF COMMERCE International Trade Administration [C-533-858] Certain Oil Country Tubular... producers and exporters of certain oil tubular goods (OCTG) from India. The period of investigation is...

The Design and Performance Evaluation of Hydroformed Tubular Torsion Beam Axle

Science.gov (United States)

Kim, Jaehyun; Oh, Jinho; Choi, Hanho

2010-06-01

Suspensions for vehicles are structural devices used for suspending a vehicle body and absorbing shocks from the road. Thus, the suspensions must be designed such that they can attenuate shocks from a road and make passengers feel comfortable despite the shocks, and improve steering stability, determined by the ground contact force of tires during running of vehicles. Another important factor to be considered while designing suspensions is that the suspensions must maintain desired stiffness and desired durability despite the repeated application of shocks from roads thereto. The present relates, in general, to a tubular torsion beam for rear suspensions of vehicles and a manufacturing method thereof and, more particularly, to the provision of tubular torsion beams having excellent roll stiffness and excellent roll strength, produced through hydroforming. The hydroforming technology has a lot of benefit which is shape accuracy, good durability caused by compressive pressure, and good forming quality. In this study, the performance evaluation of the hydroformed tubular torsion beam axle is evaluated.

A technical case report on use of tubular retractors for anterior cervical spine surgery.

Science.gov (United States)

Kulkarni, Arvind G; Patel, Ankit; Ankith, N V

2017-12-19

The authors put-forth this technical report to establish the feasibility of performing an anterior cervical corpectomy and fusion (ACCF) and a two-level anterior cervical discectomy and fusion (ACDF) using a minimally invasive approach with tubular retractors. First case: cervical spondylotic myelopathy secondary to a large postero-inferiorly migrated disc treated with corpectomy and reconstruction with a mesh cage and locking plate. Second case: cervical disc herniation with radiculopathy treated with a two-level ACDF. Both cases were operated with minimally invasive approach with tubular retractor using a single incision. Technical aspects and clinical outcomes have been reported. No intra or post-operative complications were encountered. Intra-operative blood loss was negligible. The patients had a cosmetic scar on healing. Standard procedure of placement of tubular retractors is sufficient for adequate surgical exposure with minimal invasiveness. Minimally invasive approach to anterior cervical spine with tubular retractors is feasible. This is the first report on use of minimally invasive approach for ACCF and two-level ACDF.

Reactive oxygen species promote tubular injury in diabetic nephropathy: The role of the mitochondrial ros-txnip-nlrp3 biological axis

Directory of Open Access Journals (Sweden)

Yachun Han

2018-06-01

Full Text Available NLRP3/IL-1β activation via thioredoxin (TRX/thioredoxin-interacting protein (TXNIP following mitochondria ROS (mtROS overproduction plays a key role in inflammation. However, the involvement of this process in tubular damage in the kidneys of patients with diabetic nephropathy (DN is unclear. Here, we demonstrated that mtROS overproduction is accompanied by decreases in TRX expression and TXNIP up-regulation. In addition, we discovered that mtROS overproduction is also associated with increases in NLRP3/IL-1β and TGF-β expression in the kidneys of patients with DN and db/db mice. We reversed these changes in db/db mice by administering a peritoneal injection of MitoQ, an antioxidant targeting mtROS. Similar results were observed in human tubular HK-2 cells subjected to high-glucose (HG conditions and treated with MitoQ. Treating HK-2 cells with MitoQ suppressed the dissociation of TRX from TXNIP and subsequently blocked the interaction between TXNIP and NLRP3, leading to the inhibition of NLRP3 inflammasome activation and IL-1β maturation. The effects of MitoQ were enhanced by pretreatment with TXNIP siRNA and abolished by pretreatment with monosodium urate (MSU and TRX siRNA in vitro. These results suggest that mitochondrial ROS-TXNIP/NLRP3/IL-1β axis activation is responsible for tubular oxidative injury, which can be ameliorated by MitoQ via the inhibition of mtROS overproduction. Keywords: Diabetic nephropathy, Mitochondria, Reactive oxygen species (ROS, TRX/TXNIP, NLRP3 inflammasome, MitoQ

Cytotoxicity of S-conjugates of the sevoflurane degradation product fluoromethyl-2,2-difluoro-1-(trifluoromethyl) vinyl ether (Compound A) in a human proximal tubular cell line

International Nuclear Information System (INIS)

Altuntas, T. Gul; Zager, Richard A.; Kharasch, Evan D.

2003-01-01

Fluoromethyl-2,2-difluoro-1-(trifluoromethyl)vinyl ether (FDVE) is a fluorinated alkene formed by degradation of the volatile anesthetic sevoflurane in anesthesia machines. FDVE is nephrotoxic in rats but not humans. Rat FDVE nephrotoxicity is attributed to FDVE glutathione conjugation and bioactivation of subsequent FDVE-cysteine S-conjugates, in part by renal β-lyase. Although FDVE conjugation and metabolism occur in both rats and humans, the mechanism for selective toxicity in rats and lack of effect in humans is incompletely elucidated. This investigation measured FDVE S-conjugate cytotoxicity in cultured human proximal tubular HK-2 cells, and compared this with known cytotoxic S-conjugates. HK-2 cells were incubated with FDVE and its GSH, cysteine S-mercapturic acid, cysteine S-sulfoxide, and mercapturic acid sulfoxide conjugates (0.1-2.7 mM) for 24 h. Cytotoxicity was determined by lactate dehydrogenase (LDH) release, total LDH, and the ability of viable cells to reduce a tetrazolium-based compound (MTT). FDVE was cytotoxic only at concentrations ≥0.9 mM. No increase in LDH release was observed with either FDVE-GSH conjugate. The FDVE-cysteine conjugates S-(1,1-difluoro-2-fluoromethoxy-2-(trifluoromethyl) ethyl)-L-cysteine (DFEC) and (Z)-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl) vinyl)-L-cysteine ((Z)-FFVC) caused significant differences in LDH release and MTT reduction only at 2.7 mM; (Z)-FFVC was slightly more cytotoxic. Both S-(1,1-difluoro-2-fluoromethoxy-2-(trifluoromethyl) ethyl)-L-cysteine sulfoxide (DFEC-SO) and (Z)-N-acetyl-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl) vinyl)-L-cysteine sulfoxide ((Z)-N-Ac-FFVC-SO) caused slightly greater changes in LDH release or total LDH than the corresponding equimolar DFEC and (Z)-N-acetyl-S-(1-fluoro-2-fluoromethoxy-2-(trifluoromethyl) vinyl)-L-cysteine ((Z)-N-Ac-FFVC) conjugates. In contrast to FDVE S-conjugates, S-(1,2-dichlorovinyl)-L-cysteine was markedly cytotoxic, at concentrations as low as 0

Free energy barriers to evaporation of water in hydrophobic confinement.

Science.gov (United States)

Sharma, Sumit; Debenedetti, Pablo G

2012-11-08

We use umbrella sampling Monte Carlo and forward and reverse forward flux sampling (FFS) simulation techniques to compute the free energy barriers to evaporation of water confined between two hydrophobic surfaces separated by nanoscopic gaps, as a function of the gap width, at 1 bar and 298 K. The evaporation mechanism for small (1 × 1 nm(2)) surfaces is found to be fundamentally different from that for large (3 × 3 nm(2)) surfaces. In the latter case, the evaporation proceeds via the formation of a gap-spanning tubular cavity. The 1 × 1 nm(2) surfaces, in contrast, are too small to accommodate a stable vapor cavity. Accordingly, the associated free energy barriers correspond to the formation of a critical-sized cavity for sufficiently large confining surfaces, and to complete emptying of the gap region for small confining surfaces. The free energy barriers to evaporation were found to be of O(20kT) for 14 Å gaps, and to increase by approximately ~5kT with every 1 Å increase in the gap width. The entropy contribution to the free energy of evaporation was found to be independent of the gap width.

ANALYSIS OF ELASTIC DEFORMATION OF BRAIDED TUBULAR STRUCTURES FOR MEDICAL APPLICATIONS

Directory of Open Access Journals (Sweden)

Mehmet Emin YÜKSEKKAYA

2001-02-01

Full Text Available In this study, self-expanding stents were fabricated and analyzed. These stents are in the form of 3-D tubular braided structures made of polymeric materials. This type of structures is used in medicine to open clogged artheries and veins by exerting radial force. The amount of radial force exerted into the membrane should not give any damage to the veins. Therefore, the geometry of the three dimensional tubular braided fabric is analyzed to give an optimum radial force for medical applications.

Self-assembly of versatile tubular-like In2O3 nanostructures

International Nuclear Information System (INIS)

Zhong Miao; Zheng Maojun; Ma Li; Li Yanbo

2007-01-01

Versatile indium oxide tubular nanostructures (well-aligned nanotube arrays, flower-like tubular structures, and square nanotubes) were fabricated by a facile and reliable chemical vapor deposition (CVD) technique, taking advantage of the self-assembly property and substrate-induced epitaxial growth mechanism. The technique has a few advantages, such as low growth temperature, nonexistence of catalyst, template-free synthesis, direct bonding to the semiconductor substrates, etc. This strategy might extend the approach of synthesizing desirable nanostructures of other important low-melting metal oxides for potential applications

Facile Fabrication of Uniform Polyaniline Nanotubes with Tubular Aluminosilicates as Templates

Science.gov (United States)

Zhang, Long; Liu, Peng

2008-08-01

The uniform polyaniline (PANI) nanotubes, with inner diameter, outer diameter, and tubular thickness of 40, 60, and 10 nm, respectively, were prepared successfully by using natural tubular aluminosilicates as templates. The halloysite nanotubes were coated with PANI via the in situ chemical oxidation polymerization. Then the templates were etched with HCl/HF solution. The PANI nanotubes were characterized using FTIR, X-ray diffraction, and transmission electron microscopy. The conductivity of the PANI nanotubes was found to be 1.752 × 10-5 (Ω·cm)-1.

Autoimmune Hepatitis with Distal Renal Tubular Acidosis and Small Bowel Partial Malrotation.

Science.gov (United States)

Kanaiyalal Modi, Tejas; Parikh, Hardik; Sadalge, Abhishek; Gupte, Amit; Bhatt, Pratin; Shukla, Akash

2015-01-01

Renal tubular acidosis (RTA) is not uncommon in patient with chronic autoimmune hepatitis (AIH), but usually remains latent. Here, we report a case of renal tubular acidosis RTA who presented with AIH. She was also diagnosed to have partial bowel malrotation. A 9-year-old girl, a case of distal RTA, presented with jaundice, abdominal distension and altered sensorium. She was diagnosed to be AIH, which was successfully treated with steroids and azathioprine. Coexistent midgut partial malrotation with volvulus was diagnosed during the treatment. She was treated successfully with anti-tuberculous treatment for cervical lymphadenitis. Autoimmune hepatitis should not be ruled out in each case of RTA presenting with jaundice. Modi TK, Parikh H, Sadalge A, Gupte A, Bhatt P, Shukla A. Autoimmune Hepatitis with Distal Renal Tubular Acidosis and Small Bowel Partial Malrotation. Euroasian J Hepato-Gastroenterol 2015;5(2):107-109.

γδ T cells in homeostasis and host defence of epithelial barrier tissues

DEFF Research Database (Denmark)

Nielsen, Morten M.; Witherden, Deborah A.; Havran, Wendy L.

2017-01-01

Epithelial surfaces line the body and provide a crucial interface between the body and the external environment. Tissue-resident epithelial γδ T cells represent a major T cell population in the epithelial tissues and are ideally positioned to carry out barrier surveillance and aid in tissue...... homeostasis and repair. In this Review, we focus on the intraepithelial γδ T cell compartment of the two largest epithelial tissues in the body — namely, the epidermis and the intestine — and provide a comprehensive overview of the crucial contributions of intraepithelial γδ T cells to tissue integrity...

Mechanical testing of adherence of stacked layers in tubular geometry

Energy Technology Data Exchange (ETDEWEB)

Correia, L.A.; Schuring, E.W.; Van Delft, Y.C. [ECN Energy Efficiency in the Industry, Petten (Netherlands)

2007-09-15

For the development of new molecular separation technologies strong robust tubular membrane systems are required. The fragile membranes, however, need a strong defect free support such as a porous asymmetric ceramic tube. Mechanical failure of these ceramic membrane systems during manufacturing and operation is mainly caused by delamination of the stacked layers. Therefore development is focused on improving the adherence. As no standard mechanical test for tubular samples is available yet, a new tensile test was developed to facilitate the current research. The most important components in the new equipment is a test tool with a curvature matching that of the test sample and a sample casing that align and guide the test tool during the tensile test. With this tensile test the manufacturing procedure for the ECN standard tubular {alpha}-alumina support was optimized. Firing the asymmetric support at 1300C resulted in the highest mechanical strength for the support system with cohesive fracture in the support tube. With the test developed the process condition could be identified where the material of the support tube is the weakest link in the support system.

Strain-Induced Rolled Thin Films for Lightweight Tubular Thermoelectric Generators

KAUST Repository

Singh, Devendra

2017-11-24

Thermoelectric generators (TEGs) are interesting energy harvesters of otherwise wasted heat. Here, a polymer-assisted generic process and its mechanics to obtain sputtered thermoelectric (TE) telluride material-based 3D tubular structures with unprecedented length (up to seamless 4 cm and further expandable) are shown. This length allows for large temperature differences between the hot and the cold ends, a critical but untapped enabler for high power generation. Compared with a flat slab, better area efficiency is observed for a rolled tube and compared with a solid rod architecture, a rolled tube uses less material (thus making it lightweight and cost effective) and has competitive performance advantage due to a smaller contact area. It is also shown that a tubular architecture thermopile-based TEG is able to generate up to 5 μW of power (eight pairs of p- and n-type thermopiles) through a temperature difference of 60 °C. The demonstrated process can play an important role in transforming 2D atomic crystal structure TE materials into 3D tubular thermopiles for effective TEG application, which can maintain higher temperature differences by longer distances between hot and cold ends.

Filament winding technique, experiment and simulation analysis on tubular structure

Science.gov (United States)

Quanjin, Ma; Rejab, M. R. M.; Kaige, Jiang; Idris, M. S.; Harith, M. N.

2018-04-01

Filament winding process has emerged as one of the potential composite fabrication processes with lower costs. Filament wound products involve classic axisymmetric parts (pipes, rings, driveshafts, high-pressure vessels and storage tanks), non-axisymmetric parts (prismatic nonround sections and pipe fittings). Based on the 3-axis filament winding machine has been designed with the inexpensive control system, it is completely necessary to make a relative comparison between experiment and simulation on tubular structure. In this technical paper, the aim of this paper is to perform a dry winding experiment using the 3-axis filament winding machine and simulate winding process on the tubular structure using CADWIND software with 30°, 45°, 60° winding angle. The main result indicates that the 3-axis filament winding machine can produce tubular structure with high winding pattern performance with different winding angle. This developed 3-axis winding machine still has weakness compared to CAWIND software simulation results with high axes winding machine about winding pattern, turnaround impact, process error, thickness, friction impact etc. In conclusion, the 3-axis filament winding machine improvements and recommendations come up with its comparison results, which can intuitively understand its limitations and characteristics.

Facile Fabrication of Uniform Polyaniline Nanotubes with Tubular Aluminosilicates as Templates

Directory of Open Access Journals (Sweden)

Zhang Long

2008-01-01

Full Text Available AbstractThe uniform polyaniline (PANI nanotubes, with inner diameter, outer diameter, and tubular thickness of 40, 60, and 10 nm, respectively, were prepared successfully by using natural tubular aluminosilicates as templates. The halloysite nanotubes were coated with PANI via the in situ chemical oxidation polymerization. Then the templates were etched with HCl/HF solution. The PANI nanotubes were characterized using FTIR, X-ray diffraction, and transmission electron microscopy. The conductivity of the PANI nanotubes was found to be 1.752 × 10−5(Ω·cm−1.

Mathematical modeling of solid oxide fuel cells

Science.gov (United States)

Lu, Cheng-Yi; Maloney, Thomas M.

1988-01-01

Development of predictive techniques, with regard to cell behavior, under various operating conditions is needed to improve cell performance, increase energy density, reduce manufacturing cost, and to broaden utilization of various fuels. Such technology would be especially beneficial for the solid oxide fuel cells (SOFC) at it early demonstration stage. The development of computer models to calculate the temperature, CD, reactant distributions in the tubular and monolithic SOFCs. Results indicate that problems of nonuniform heat generation and fuel gas depletion in the tubular cell module, and of size limitions in the monolithic (MOD 0) design may be encountered during FC operation.

Nano-tubular cellulose for bioprocess technology development.

Directory of Open Access Journals (Sweden)

Athanasios A Koutinas

Full Text Available Delignified cellulosic material has shown a significant promotional effect on the alcoholic fermentation as yeast immobilization support. However, its potential for further biotechnological development is unexploited. This study reports the characterization of this tubular/porous cellulosic material, which was done by SEM, porosimetry and X-ray powder diffractometry. The results showed that the structure of nano-tubular cellulose (NC justifies its suitability for use in "cold pasteurization" processes and its promoting activity in bioprocessing (fermentation. The last was explained by a glucose pump theory. Also, it was demonstrated that crystallization of viscous invert sugar solutions during freeze drying could not be otherwise achieved unless NC was present. This effect as well as the feasibility of extremely low temperature fermentation are due to reduction of the activation energy, and have facilitated the development of technologies such as wine fermentations at home scale (in a domestic refrigerator. Moreover, NC may lead to new perspectives in research such as the development of new composites, templates for cylindrical nano-particles, etc.

Flow analysis of tubular fuel assembly using CFD code

International Nuclear Information System (INIS)

Park, J. H.; Park, C.; Chae, H. T.

2004-01-01

Based on the experiences of HANARO, a new research reactor is under conceptual design preparing for future needs of research reactor. Considering various aspects such as nuclear physics, thermal-hydraulics, mechanical structure and the applicability of HANARO technology, a tubular type fuel has been considered as that of a new research reactor. Tubular type fuel has several circular fuel layers, and each layer consists of 3 curved fuel plates arranged with constant small gap to build up cooling channels. In the thermal-hydraulic point, it is very important to maintain each channel flow velocity be equal as much as possible, because the small gaps between curved thin fuel plates independently forms separate coolant channels, which may cause a thermal-hydraulic problem in certain conditions. In this study, commercial CFD(Computational Fluid Dynamics) code, Fluent, has been used to investigate flow characteristics of tubular type fuel assembly. According to the computation results for the preliminary conceptual design, there is a serious lack of uniformity of average velocity on the each coolant channel. Some changes for initial conceptual design were done to improve the balance of velocity distribution, and analysis was done again, too. The results for the revised design showed that the uniformity of each channel velocity was improved significantly. The influence of outermost channel gap width on the velocity distribution was also examined

Status report on the development of a tubular electron beam ion source

International Nuclear Information System (INIS)

Donets, E.D.; Donets, E.E.; Becker, R.; Liljeby, L.; Rensfelt, K.-G.; Beebe, E.N.; Pikin, A.I.

2004-01-01

The theoretical estimations and numerical simulations of tubular electron beams in both beam and reflex mode of source operation as well as the off-axis ion extraction from a tubular electron beam ion source (TEBIS) are presented. Numerical simulations have been done with the use of the IGUN and OPERA-3D codes. Numerical simulations with IGUN code show that the effective electron current can reach more than 100 A with a beam current density of about 300-400 A/cm 2 and the electron energy in the region of several KeV with a corresponding increase of the ion output. Off-axis ion extraction from the TEBIS, being the nonaxially symmetric problem, was simulated with OPERA-3D (SCALA) code. The conceptual design and main parameters of new tubular sources which are under consideration at JINR, MSL, and BNL are based on these simulations

Active barrier films of PET for solar cell application: Processing and characterization

International Nuclear Information System (INIS)

Rossi, Gabriella; Scarfato, Paola; Incarnato, Loredana

2014-01-01

A preliminary investigation was carried out on the possibility to improve the protective action offered by the standard multilayer structures used to encapsulate photovoltaic devices. With this aim, a commercial active barrier PET-based material, able to absorb oxygen when activated by liquid water, was used to produce flexible and transparent active barrier films, by means of a lab-scale film production plant. The obtained film, tested in terms of thermal, optical and oxygen absorption properties, shows a slow oxygen absorption kinetics, an acceptable transparency and an easy roll-to-roll processability, so proving itself as a good candidate for the development of protective coating for solar cells against the atmospheric degradation agents like the rain

Glomerular filtration and tubular secretion of MAG-3 in the rat kidney

International Nuclear Information System (INIS)

Mueller-Suur, R.M.; Mueller-Suur, C.

1989-01-01

Technetium-99m mercaptoacetyltriglycine (MAG-3) has recently been introduced as a new radiopharmaceutical for dynamic renal scintigraphy. To elucidate the mechanism of renal excretion, micropuncture experiments were performed in rat kidneys for direct measurements of glomerular filtration and tubular secretory capacity. Fluid of Bowman space was collected from superficial glomeruli and analyzed for its contents of [99mTc]MAG-3, [125I]hippurate and [3H]inulin during constant infusion of these compounds. The ratio of activity of ultrafiltrate to that of arterial plasma was 0.23 for MAG-3, 0.68 for hippurate and 1.04 for inulin which demonstrates that the filtrated amount of MAG-3 is only 23% of that of inulin, presumably because of higher plasma protein binding which was also measured in vitro and found to be 80 +/- 1.5% for MAG-3 and 32 +/- 2% for [125I]hippurate. Proximal and distal tubules were also micropunctured and their tubular fluid as well as the final urine analyzed for the activity of hippurate and MAG-3. The tubular fluid to plasma ratio values along the nephron and in the final urine were all lower for MAG-3 than for hippurate, indicating a lower secretory capacity. From measurements of whole renal clearance, GFR and plasma protein binding the filtered amount of MAG-3 was 0.26 and of hippurate 0.87 ml/min.g kidney weight (p less than 0.001) and the secreted amount 2.01 and 2.38 ml/min.g kidney weight (p less than 0.05), respectively. We conclude that MAG-3 is predominantly excreted by tubular secretion and that the lower renal clearance of MAG-3 as compared with that of hippurate is a result both of a substantially decreased glomerular filtration and of a lower tubular secretion

Gliovascular and cytokine interactions modulate brain endothelial barrier in vitro.

Science.gov (United States)

Chaitanya, Ganta V; Cromer, Walter E; Wells, Shannon R; Jennings, Merilyn H; Couraud, P Olivier; Romero, Ignacio A; Weksler, Babette; Erdreich-Epstein, Anat; Mathis, J Michael; Minagar, Alireza; Alexander, J Steven

2011-11-23

The glio-vascular unit (G-unit) plays a prominent role in maintaining homeostasis of the blood-brain barrier (BBB) and disturbances in cells forming this unit may seriously dysregulate BBB. The direct and indirect effects of cytokines on cellular components of the BBB are not yet unclear. The present study compares the effects of cytokines and cytokine-treated astrocytes on brain endothelial barrier. 3-dimensional transwell co-cultures of brain endothelium and related-barrier forming cells with astrocytes were used to investigate gliovascular barrier responses to cytokines during pathological stresses. Gliovascular barrier was measured using trans-endothelial electrical resistance (TEER), a sensitive index of in vitro barrier integrity. We found that neither TNF-α, IL-1β or IFN-γ directly reduced barrier in human or mouse brain endothelial cells or ECV-304 barrier (independent of cell viability/metabolism), but found that astrocyte exposure to cytokines in co-culture significantly reduced endothelial (and ECV-304) barrier. These results indicate that the barrier established by human and mouse brain endothelial cells (and other cells) may respond positively to cytokines alone, but that during pathological conditions, cytokines dysregulate the barrier forming cells indirectly through astrocyte activation involving reorganization of junctions, matrix, focal adhesion or release of barrier modulating factors (e.g. oxidants, MMPs). © 2011 Chaitanya et al; licensee BioMed Central Ltd.

The rebirth of interest in renal tubular function.

Science.gov (United States)

Lowenstein, Jerome; Grantham, Jared J

2016-06-01

The measurement of glomerular filtration rate by the clearance of inulin or creatinine has evolved over the past 50 years into an estimated value based solely on plasma creatinine concentration. We have examined some of the misconceptions and misunderstandings of the classification of renal disease and its course, which have followed this evolution. Furthermore, renal plasma flow and tubular function, which in the past were estimated by the clearance of the exogenous aryl amine, para-aminohippurate, are no longer measured. Over the past decade, studies in experimental animals with reduced nephron mass and in patients with reduced renal function have identified small gut-derived, protein-bound uremic retention solutes ("uremic toxins") that are poorly filtered but are secreted into the lumen by organic anion transporters (OATs) in the proximal renal tubule. These are not effectively removed by conventional hemodialysis or peritoneal dialysis. Residual renal function, urine produced in patients with advanced renal failure or undergoing dialysis treatment, may represent, at least in part, secretion of fluid and uremic toxins, such as indoxyl sulfate, mediated by proximal tubule OATs and might serve as a useful survival function. In light of this new evidence of the physiological role of proximal tubule OATs, we suggest that measurement of renal tubular function and renal plasma flow may be of considerable value in understanding and managing chronic kidney disease. Data obtained in normal subjects indicate that renal plasma flow and renal tubular function might be measured by the clearance of the endogenous aryl amine, hippurate. Copyright © 2016 the American Physiological Society.

Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

KAUST Repository

Nehe, Prashant

2015-05-01

Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

The Test for Flow Characteristics of Tubular Fuel Assembly(II) - Experimental results and CFD analysis

International Nuclear Information System (INIS)

Park, Jong Hark; Chae, H. T.; Park, C.; Kim, H.

2006-12-01

A test facility had been established for the experiment of velocity distribution and pressure drop in a tubular fuel. A basic test had been conducted to examine the performance of the test loop and to verify the accuracy of measurement by pitot-tube. In this report, test results and CFD analysis for the hydraulic characteristics of a tubular fuel, following the previous tests, are described. Coolant velocities in all channels were measured using pitot-tube and the effect of flow rate change on the velocity distribution was also examined. The pressure drop through the tubular fuel was measured for various flow rates in range of 1 kg/s to 21 kg/s to obtain a correlation of pressure drop with variation of flow rate. In addition, a CFD(Computational Fluid Dynamics) analysis was also done to find out the hydraulic characteristics of tubular fuel such as velocity distribution and pressure drop. As the results of CFD analysis can give us a detail insight on coolant flow in the tubular fuel, the CFD method is a very useful tool to understand the flow structure and phenomena induced by fluid flow. The CFX-10, a commercial CFD code, was used in this study. The two results by the experiment and the CFD analysis were investigated and compared with each other. Overall trend of velocity distribution by CFD analysis was somewhat different from that of experiment, but it would be reasonable considering measurement uncertainties. The CFD prediction for pressure drop of a tubular fuel shows a tolerably good agreement with experiment within 8% difference

Microstructure and mechanical properties of AZ91 tubes fabricated by Multi-pass Parallel Tubular Channel Angular Pressing

OpenAIRE

Hooman Abdolvand; Ghader Faraji; Javad Shahbazi Karami

2017-01-01

Parallel Tubular Channel Angular Pressing (PTCAP) process is a novel recently developed severe plastic deformation (SPD) method for producing ultrafine grained (UFG) and nanograined (NG) tubular specimens with excellent mechanical and physical properties. This process has several advantageous compared to its TCAP counterparts. In this paper, a fine grained AZ91 tube was fabricated via multi pass parallel tubular channel angular pressing (PTCAP) process. Tubes were processed up to three passes...

Furosemide/Fludrocortisone Test and Clinical Parameters to Diagnose Incomplete Distal Renal Tubular Acidosis in Kidney Stone Formers.

Science.gov (United States)

Dhayat, Nasser A; Gradwell, Michael W; Pathare, Ganesh; Anderegg, Manuel; Schneider, Lisa; Luethi, David; Mattmann, Cedric; Moe, Orson W; Vogt, Bruno; Fuster, Daniel G

2017-09-07

Incomplete distal renal tubular acidosis is a well known cause of calcareous nephrolithiasis but the prevalence is unknown, mostly due to lack of accepted diagnostic tests and criteria. The ammonium chloride test is considered as gold standard for the diagnosis of incomplete distal renal tubular acidosis, but the furosemide/fludrocortisone test was recently proposed as an alternative. Because of the lack of rigorous comparative studies, the validity of the furosemide/fludrocortisone test in stone formers remains unknown. In addition, the performance of conventional, nonprovocative parameters in predicting incomplete distal renal tubular acidosis has not been studied. We conducted a prospective study in an unselected cohort of 170 stone formers that underwent sequential ammonium chloride and furosemide/fludrocortisone testing. Using the ammonium chloride test as gold standard, the prevalence of incomplete distal renal tubular acidosis was 8%. Sensitivity and specificity of the furosemide/fludrocortisone test were 77% and 85%, respectively, yielding a positive predictive value of 30% and a negative predictive value of 98%. Testing of several nonprovocative clinical parameters in the prediction of incomplete distal renal tubular acidosis revealed fasting morning urinary pH and plasma potassium as the most discriminative parameters. The combination of a fasting morning urinary threshold pH 3.8 mEq/L yielded a negative predictive value of 98% with a sensitivity of 85% and a specificity of 77% for the diagnosis of incomplete distal renal tubular acidosis. The furosemide/fludrocortisone test can be used for incomplete distal renal tubular acidosis screening in stone formers, but an abnormal furosemide/fludrocortisone test result needs confirmation by ammonium chloride testing. Our data furthermore indicate that incomplete distal renal tubular acidosis can reliably be excluded in stone formers by use of nonprovocative clinical parameters. Copyright © 2017 by the American

Smart concrete slabs with embedded tubular PZT transducers for damage detection

Science.gov (United States)

Gao, Weihang; Huo, Linsheng; Li, Hongnan; Song, Gangbing

2018-02-01

The objective of this study is to develop a new concept and methodology of smart concrete slab (SCS) with embedded tubular lead zirconate titanate transducer array for image based damage detection. Stress waves, as the detecting signals, are generated by the embedded tubular piezoceramic transducers in the SCS. Tubular piezoceramic transducers are used due to their capacity of generating radially uniform stress waves in a two-dimensional concrete slab (such as bridge decks and walls), increasing the monitoring range. A circular type delay-and-sum (DAS) imaging algorithm is developed to image the active acoustic sources based on the direct response received by each sensor. After the scattering signals from the damage are obtained by subtracting the baseline response of the concrete structures from those of the defective ones, the elliptical type DAS imaging algorithm is employed to process the scattering signals and reconstruct the image of the damage. Finally, two experiments, including active acoustic source monitoring and damage imaging for concrete structures, are carried out to illustrate and demonstrate the effectiveness of the proposed method.

78 FR 77420 - Certain Oil Country Tubular Goods From the Republic of Turkey: Preliminary Negative...

Science.gov (United States)

2013-12-23

..., the Republic of the Philippines, Saudi Arabia, Taiwan, Thailand, the Republic of Turkey, Ukraine, and... DEPARTMENT OF COMMERCE International Trade Administration [C-489-817] Certain Oil Country Tubular... provided to producers and exporters of certain oil tubular goods (OCTG) from the Republic of Turkey (Turkey...

Long-term enzyme replacement therapy is associated with reduced proteinuria and preserved proximal tubular function in women with Fabry disease

DEFF Research Database (Denmark)

Prabakaran, Thaneas; Birn, Henrik; Bibby, Bo M

2014-01-01

dysfunction in women with Fabry disease treated with ERT. METHODS: A retrospective, single centre, cohort study evaluated the long-term association between ERT, albuminuria and eGFR in 13 women with Fabry disease and mild renal involvement. In particular, we analysed the changes in the proteinuric profile...... to end-stage renal failure. In women with Fabry disease, accumulation of GL-3 in the glomerular podocytes and other renal cells induces progressive, proteinuric nephropathy, but not as severe as in men. Enzyme replacement therapy (ERT) with recombinant α-Gal A reduces cellular GL-3 deposits in podocytes...... in albuminuria was paralleled by a decrease in both glomerular and tubular urine protein markers. CONCLUSIONS: The data indicate that long-term ERT is associated with a reduction in albuminuria and glomerular and tubular urinary protein markers in women with Fabry disease and mild renal manifestations....

Distal Renal Tubular Acidosis (dRTA) Among Southeast Asian Ovalocytosis (SAO) Patients in Malaria Endemic Area of Sekotong, Lombok Island

OpenAIRE

Danuyanti, I Gusti Ayu Nyoman; -, Tasmini; Sadewa, Ahmad Hamim

2014-01-01

Introduction: Southeast Asian Ovalocytosis (SAO) is caused by 27 bp deletion of the band 3 protein gene in erythrocyte membrane and characterized by oval erythrocyte. The erythroid band 3 (AE1) gene isexpressed not only in erythrocyte membranes but also in the cell membrane of α-collecting renal tubular functions in the secretion of acid in renal tubules and HCO3 -/Cl- anion exchange. An alteration of the band 3 (AE1) gene functions in cell of α-collecting renal tubules reduces HCO3-/Cl- ion ...

Apoptosis of Endothelial Cells by 13-HPODE Contributes to Impairment of Endothelial Barrier Integrity

Directory of Open Access Journals (Sweden)

Valerie E. Ryman

2016-01-01

Full Text Available Inflammation is an essential host response during bacterial infections such as bovine mastitis. Endothelial cells are critical for an appropriate inflammatory response and loss of vascular barrier integrity is implicated in the pathogenesis of Streptococcus uberis-induced mastitis. Previous studies suggested that accumulation of linoleic acid (LA oxygenation products derived from 15-lipoxygenase-1 (15-LOX-1 metabolism could regulate vascular functions. The initial LA derivative from the 15-LOX-1 pathway, 13-hydroperoxyoctadecadienoic acid (HPODE, can induce endothelial death, whereas the reduced hydroxyl product, 13-hydroxyoctadecadienoic acid (HODE, is abundantly produced during vascular activation. However, the relative contribution of specific LA-derived metabolites on impairment of mammary endothelial integrity is unknown. Our hypothesis was that S. uberis-induced LA-derived 15-LOX-1 oxygenation products impair mammary endothelial barrier integrity by apoptosis. Exposure of bovine mammary endothelial cells (BMEC to S. uberis did not increase 15-LOX-1 LA metabolism. However, S. uberis challenge of bovine monocytes demonstrated that monocytes may be a significant source of both 13-HPODE and 13-HODE during mastitis. Exposure of BMEC to 13-HPODE, but not 13-HODE, significantly reduced endothelial barrier integrity and increased apoptosis. Changing oxidant status by coexposure to an antioxidant during 13-HPODE treatment prevented adverse effects of 13-HPODE, including amelioration of apoptosis. A better understanding of how the oxidant status of the vascular microenvironment impacts endothelial barrier properties could lead to more efficacious treatments for S. uberis mastitis.

Stepwise DNA Methylation Changes Are Linked to Escape from Defined Proliferation Barriers and Mammary Epithelial Cell Immortalization

Energy Technology Data Exchange (ETDEWEB)

Novak, Petr; Jensen, Taylor J.; Garbe, James C.; Stampfer, Martha R.; Futscher, Bernard W.

2009-04-20

The timing and progression of DNA methylation changes during carcinogenesis are not completely understood. To develop a timeline of aberrant DNA methylation events during malignant transformation, we analyzed genome-wide DNA methylation patterns in an isogenic human mammary epithelial cell (HMEC) culture model of transformation. To acquire immortality and malignancy, the cultured finite lifespan HMEC must overcome two distinct proliferation barriers. The first barrier, stasis, is mediated by the retinoblastoma protein and can be overcome by loss of p16(INK4A) expression. HMEC that escape stasis and continue to proliferate become genomically unstable before encountering a second more stringent proliferation barrier, telomere dysfunction due to telomere attrition. Rare cells that acquire telomerase expression may escape this barrier, become immortal, and develop further malignant properties. Our analysis of HMEC transitioning from finite lifespan to malignantly transformed showed that aberrant DNA methylation changes occur in a stepwise fashion early in the transformation process. The first aberrant DNA methylation step coincides with overcoming stasis, and results in few to hundreds of changes, depending on how stasis was overcome. A second step coincides with immortalization and results in hundreds of additional DNA methylation changes regardless of the immortalization pathway. A majority of these DNA methylation changes are also found in malignant breast cancer cells. These results show that large-scale epigenetic remodeling occurs in the earliest steps of mammary carcinogenesis, temporally links DNA methylation changes and overcoming cellular proliferation barriers, and provides a bank of potential epigenetic biomarkers that mayprove useful in breast cancer risk assessment.

Renal tubular dysfunction in pediatric patients with beta-thalassemia major

Directory of Open Access Journals (Sweden)

Ali Ahmadzadeh

2011-01-01

Full Text Available To evaluate the prevalence of renal tubular dysfunction in children with β-thalassemia (β-T major, we studied the glomerular and tubular function in 140 children with β-T major and compared them to a healthy control group at our center from May 2007 to April 2008. Fresh first morning samples were collected from each patient and analyzed for sodium, potassium, calcium (Ca, protein, uric acid (UA, creatinine (Cr, urine osmolality and urinary N-acetyl-β-D-glucosaminidase (UNAG activity. Blood samples were also collected for complete blood count, blood urea nitrogen (BUN, fasting blood sugar, serum creatinine (SCr, electrolytes, and ferritin before transfusion. Among the study patients, 72 were males, and the mean age was 11.5 (ranging 7-16 years. SCr levels were all within normal limits and all of them had normal glomerular filtration rate (GFR. The mean UNAG was 17.8 IU/L in the study patients (normal 0.15-11.5 IU/L and 3.2 IU/L in the control group (P 0.21 (P = 0.006. Nine (6.4% thalassemic patients with a mean age of 12 years had proteinuria (Upr/UCr > 0.2. Sixty-nine (49.3% out of the 140 patients and 45 (65.2% of the patients having UNAG had uricosuria also (UUA/UCr > 0.26. Ten (7% patients had microscopic hematuria and 10 (7% patients with a mean age of 13.5 years had glucosuria or diabetes mellitus. We conclude that tubular dysfunction is a relative common complication of the β-T major; UNAG and its index are the best to detect renal tubular dysfunction in these patients. Currently, periodic measurement of UCa/UCr and UUA/UCr ratios as well as urinalysis are recommended.

Effect of cisplatin on renal haemodynamics and tubular function in the dog kidney

DEFF Research Database (Denmark)

Daugaard, G; Abildgaard, U; Holstein-Rathlou, N H

1987-01-01

Administration of cisplatin (5 mg/kg) to dogs results in polyuric renal failure due initially to a proximal tubular functional impairment. 48-72 h after the cisplatin administration the depressed renal function can be attributed to impairment of proximal as well as distal tubular reabsorptive cap...... capacities associated with increased renal vascular resistance. The polyuria seems to be due to the impaired reabsorption rate in the distal nephron segments....

Effects of Lactobacillus johnsonii and Lactobacillus reuteri on gut barrier function and heat shock proteins in intestinal porcine epithelial cells.

Science.gov (United States)

Liu, Hao-Yu; Roos, Stefan; Jonsson, Hans; Ahl, David; Dicksved, Johan; Lindberg, Jan Erik; Lundh, Torbjörn

2015-04-01

Heat shock proteins (HSPs) are a set of highly conserved proteins that can serve as intestinal gate keepers in gut homeostasis. Here, effects of a probiotic, Lactobacillus rhamnosus GG (LGG), and two novel porcine isolates, Lactobacillus johnsonii strain P47-HY and Lactobacillus reuteri strain P43-HUV, on cytoprotective HSP expression and gut barrier function, were investigated in a porcine IPEC-J2 intestinal epithelial cell line model. The IPEC-J2 cells polarized on a permeable filter exhibited villus-like cell phenotype with development of apical microvilli. Western blot analysis detected HSP expression in IPEC-J2 and revealed that L. johnsonii and L. reuteri strains were able to significantly induce HSP27, despite high basal expression in IPEC-J2, whereas LGG did not. For HSP72, only the supernatant of L. reuteri induced the expression, which was comparable to the heat shock treatment, which indicated that HSP72 expression was more stimulus specific. The protective effect of lactobacilli was further studied in IPEC-J2 under an enterotoxigenic Escherichia coli (ETEC) challenge. ETEC caused intestinal barrier destruction, as reflected by loss of cell-cell contact, reduced IPEC-J2 cell viability and transepithelial electrical resistance, and disruption of tight junction protein zonula occludens-1. In contrast, the L. reuteri treatment substantially counteracted these detrimental effects and preserved the barrier function. L. johnsonii and LGG also achieved barrier protection, partly by directly inhibiting ETEC attachment. Together, the results indicate that specific strains of Lactobacillus can enhance gut barrier function through cytoprotective HSP induction and fortify the cell protection against ETEC challenge through tight junction protein modulation and direct interaction with pathogens. © 2015 The Authors. Physiological Reports published by Wiley Periodicals, Inc. on behalf of the American Physiological Society and The Physiological Society.

Evacuated, displacement compression mold. [of tubular bodies from thermosetting plastics

Science.gov (United States)

Heier, W. C. (Inventor)

1974-01-01

A process of molding long thin-wall tubular bodies from thermosetting plastic molding compounds is described wherein the tubular body lengths may be several times the diameters. The process is accomplished by loading a predetermined quantity of molding compound into a female mold cavity closed at one end by a force mandrel. After closing the other end of the female mold with a balance mandrel, the loaded cavity is evacuated by applying a vacuum of from one-to-five mm pressure for a period of fifteen-to-thirty minutes. The mold temperature is raised to the minimum temperature at which the resin constituent of the compound will soften or plasticize and a pressure of 2500 psi is applied.

Luminous effectiveness of tubular light-guides in tropics

Energy Technology Data Exchange (ETDEWEB)

Darula, Stanislav; Kittler, Richard; Kocifaj, Miroslav [ICA, Slovak Academy of Sciences, 9, Dubravska Road, 845 03 Bratislava (Slovakia)

2010-11-15

Novel tubular light-guides with a transparent hemispherical cupola placed on an unobstructed flat roof collect all sunlight and skylight available at ground level year round. This advantage is heightened in the dry and sunny tropical regions where the sun rises to very high altitudes and often the hours of sunshine last throughout the whole day. Hollow light-guides with very high inner specular reflectances can transport sunbeams downward into the windowless building core very effectively. Due to the tube's diameter and length and multiple reflections, complex illuminance patterns are produced on the underside of the tube, i.e. on top of the glazed ceiling aperture that illuminates the interior space or its working plane. This paper discusses several daylight conditions in tropical interiors illuminated by tubular light-guides. The recently published HOLIGILM calculation program and the user-friendly tool HOLIGILM 4.2 have facilitated the production of this paper. (author)

Characterization of Foam Catalysts as Packing for Tubular Reactors.

Czech Academy of Sciences Publication Activity Database

Lali, Farzad

2016-01-01

Roč. 105, JUL 2016 (2016), s. 1-9 ISSN 0255-2701 Institutional support: RVO:67985858 Keywords : overall mass transfer * foam catalyst * tubular reactor Subject RIV: CI - Industrial Chemistry, Chemical Engineering Impact factor: 2.234, year: 2016

Pediatric Sjogren syndrome with distal renal tubular acidosis and autoimmune hypothyroidism: an uncommon association.

Science.gov (United States)

Agarwal, Amit; Kumar, Pradeep; Gupta, Nomeeta

2015-11-01

A 14-year-old female came with the history of sudden onset weakness; during work up, she was found to have hyperchloremic metabolic acidosis with normal anion gap and normal renal function suggesting the possibility of renal tubular acidosis (RTA). On further evaluation of RTA, she had positive antinuclear antibody, anti-Ro, and anti-La antibodies. On nuclear scan of salivary glands, her left parotid gland was nonfunctional. Her parotid biopsy revealed dilated interlobular ducts engulfed by lymphoid cells. She also had autoimmune hypothyroidism as suggested by raised TSH and positive anti-TPO antibodies. At admission, her serum potassium levels were low and she was treated with intravenous potassium chloride. After she recovered from acute hypokalemic paralysis, she was started on oral potassium citrate along with phosphate supplements, hydroxychloroquine, oral prednisolone and thyroxine supplements. Over the next 6 months, she has significant reduction in the dosage of potassium, bicarbonate and phosphate and gained 3 kg of weight and 3.5 cm of height. As primary Sjogren syndrome itself is rare in pediatric population and its association with renal tubular acidosis is even rarer, we suggest considering Sjogren syndrome as a differential diagnosis during the RTA work-up is worth trying.

Sjögren syndrome presenting with hypopotassemic periodic paralysis due to renal tubular acidosis

Science.gov (United States)

Ataoglu, Esra Hayriye; Demir, Betul; Tuna, Mazhar; Çavus, Bilger; Cetin, Faik; Temiz, Levent Umit; Ozturk, Savas; Yenigun, Mustafa

2012-01-01

Summary Background: Sjögren syndrome (SS) is an autoimmune-lymphoproliferative disorder characterized by mononuclear cell infiltration of exocrine glands. Clinically, Sjögren syndrome (SS) has a wide spectrum, varying from autoimmune exocrinopathy to systemic involvement. There have been few cases reporting that primary SS developed with distal renal tubular acidosis clinically. Case Report: Here, we present a case with primary Sjögren syndrome accompanied by hypopotassemic paralysis due to renal tubular acidosis. Severe hypopotassemia, hyperchloremic metabolic acidosis, alkaline urine and disorder in urinary acidification test were observed in the biochemical examination of the 16-year-old female patient, who had applied to our clinic for extreme loss of muscle force. After the examinations it was determined that the patient had developed Type 1 RTA (distal RTA) due to primary Sjögren syndrome. Potassium and alkaline replacement was made and an immediate total recovery was achieved. Conclusions: Hypopotassemic paralysis due to primary Sjögren syndrome is a rare but severe disorder that could lead to death if not detected early and cured appropriately. Thus, effective treatment should be immediately initiated in cases where severe hypopotassemia is accompanied by metabolic acidosis, and the cases should also be examined for extraglandular involvement of SS. PMID:23569525

Zika Virus Infects Human Sertoli Cells and Modulates the Integrity of the In Vitro Blood-Testis Barrier Model.

Science.gov (United States)

Siemann, David N; Strange, Daniel P; Maharaj, Payal N; Shi, Pei-Yong; Verma, Saguna

2017-11-15

Confirmed reports of Zika virus (ZIKV) in human seminal fluid for months after the clearance of viremia suggest the ability of ZIKV to establish persistent infection in the seminiferous tubules, an immune-privileged site in the testis protected by the blood-testis barrier, also called the Sertoli cell (SC) barrier (SCB). However, cellular targets of ZIKV in human testis and mechanisms by which the virus enters seminiferous tubules remain unclear. We demonstrate that primary human SCs were highly susceptible to ZIKV compared to the closely related dengue virus and induced the expression of alpha interferon (IFN-α), key cytokines, and cell adhesion molecules (vascular cell adhesion molecule 1 [VCAM-1] and intracellular adhesion molecule 1 [ICAM-1]). Furthermore, using an in vitro SCB model, we show that ZIKV was released on the adluminal side of the SCB model with a higher efficiency than in the blood-brain barrier model. ZIKV-infected SCs exhibited enhanced adhesion of leukocytes that correlated with decreases in SCB integrity. ZIKV infection did not affect the expression of tight and adherens junction proteins such as ZO-1, claudin, and JAM-A; however, exposure of SCs to inflammatory mediators derived from ZIKV-infected macrophages led to the degradation of the ZO-1 protein, which correlated with increased SCB permeability. Taken together, our data suggest that infection of SCs may be one of the crucial steps by which ZIKV gains access to the site of spermatozoon development and identify SCs as a therapeutic target to clear testicular infections. The SCB model opens up opportunities to assess interactions of SCs with other testicular cells and to test the ability of anti-ZIKV drugs to cross the barrier. IMPORTANCE Recent outbreaks of ZIKV, a neglected mosquito-borne flavivirus, have identified sexual transmission as a new route of disease spread, which has not been reported for other flaviviruses. To be able to sexually transmit for months after the clearance of

Localization of tritiated 1-(2, 4-dichlorobenzyl)-1H-indazole-3-carboxylic acid ([3H] AF 1890) in rat testis using freeze-drying autoradiography

International Nuclear Information System (INIS)

Hilderbrandt-Stark, H.E.; Mills, J.W.; Fawcett, D.W.

1982-01-01

Tritiated 1-(2, 4-dichlorobenzyl)- 1 H-indazole-3-carboxylic acid ([ 3 H]AF 1890) was localized within rat testis using freeze-drying autoradiographic techniques. Ligated seminiferous tubule preparations were exposed in vitro to 80 microCi of [ 3 H]AF 1890 in the absence or presence of excess unlabeled AF 1890 for 30 min at 31 degrees C. Autoradiographs showed a generalized distribution of silver grains over the seminiferous epithelium, in the tubular lumen, and in the interstitial spaces. In addition, clusters of grains were concentrated over the seminiferous epithelium in regions of spermatid heads and tails and in the basal portion of the Sertoli cell cytoplasm, and over Leydig cells in the interstitial space. The generalized distribution was reduced and the grain clusters eliminated by incubation in an excess of unlabeled AF 1890. [ 3 H]inulin was used to assess the effectiveness of the tubular ligation because inulin does not normally penetrate the blood-testis barrier. This extracellular marker was not localized in the tubular lumen or in the seminiferous epithelium. Therefore, the labeling observed with [ 3 H]AF 1890 indicates that this compound crosses the blood-testis barrier

Co-extrusion of electrolyte/anode functional layer/anode triple-layer ceramic hollow fibres for micro-tubular solid oxide fuel cells-electrochemical performance study

Science.gov (United States)

Li, Tao; Wu, Zhentao; Li, K.

2015-01-01

In this study, the effects of an anode functional layer (AFL) with controlled thickness on physical and electrochemical properties of a micro-tubular SOFC have been systematically studied. A series of electrolyte/AFL/anode triple-layer hollow fibres with controllable AFL thicknesses (16.9-52.7 μm) have been fabricated via a single-step phase-inversion assisted co-extrusion technique. Both robustness of the cell and gas-tightness of the electrolyte layer are considerably improved by introducing the AFL of this type. The fracture force of the sample with the thickest AFL (9.67 N) almost doubles when compared to the electrolyte/anode dual-layer counterpart (5.24 N). Gas-tightness of the electrolyte layer is also considerably increased as AFL contributes to better-matched sintering behaviours between different components. Moreover, the formation of an AFL simultaneously with electrolyte and anode significantly improves the cell performances. The sample with the thinnest AFL (approximately 16.9 μm, 6% of the total anode thickness) leads to a 30% (from 0.89 to 1.21 W cm-2) increase in maximum power density, due to increased triple-phase boundaries (TPB). However, further increase in TPB from a thicker AFL is less effective for improving the cell performance, due to the substantially increased fuel diffusion resistance and subsequently higher concentration polarization. This indicates that the control over the AFL thickness is critically important in avoiding offsetting the benefits of extended TPB and consequently decreased cell performances.

76 FR 39071 - Certain Oil Country Tubular Goods From the People's Republic of China: Rescission of...

Science.gov (United States)

2011-07-05

... DEPARTMENT OF COMMERCE International Trade Administration [C-570-944] Certain Oil Country Tubular... administrative review of the countervailing duty order on certain oil country tubular goods (``OCTG'') from the... subject to administrative protective order (``APO'') of their responsibility concerning the disposition of...

MATHEMATICAL MODELLING OF PREFERED SOLUTIONS CHOICE FUNCTION FOR TUBULAR GAS HEATERS BY EXPERIMENTAL INFORMATIONS

Directory of Open Access Journals (Sweden)

BARSUK R. V.

2016-08-01

Full Text Available Annotation. Problems formulation. The article deals with choice functions building of preferred solutions by experimental information for tubular gas heater working on fuel granules - pellets.Further choice functions using for making technical solutions by tubular gas heaters construction and designing. Recently research analysis. There are works about choice functions construction by separate presents are examined. But full chose functions building by separate presents are not examined. Aims and tasks. There are setting aim to develop full choice functions mathematical model on separate presents by authors. The expert are connect to primary experimental data’s evaluation that estimates separate results by output functions (criteria. Its evaluations issue in experimental points paired comparison’s table form. Thus, there are necessary construct binary choice relations presents on experimental “points” set by expert that then using for full choice function’s constructing. Conclusions. There are choice function’s construction’s sequence are sets. There are posed point comparison results that characterized tubular gas heater’s condition with expert’s evaluation using. Also posed output functions comparisons by which can be characterized improving tubular gas heater’s performance or vice versa.

Tubularized incised plate technique for recurrent hypospadias: a ...

African Journals Online (AJOL)

management of recurrent hypospadias. Summary background ... The potential advantages of tubularized incised plate .... after a mean duration of 4.9 ± 3.1 years from the previous repair (Table 2). .... erection and the risk of infection, especially in patients older than 15 .... However, previous surgery often limits the availability ...

Increase of efficiency of plant materials heat treatment in tubular reactors

Directory of Open Access Journals (Sweden)

A. V. Golubkovich

2016-01-01

Full Text Available In agriculture products of pyrolysis of plant materials in the form of waste of the main production can be applied as a source of heat and electric power. Besides, their use prevents ecological pollution of the soil and the atmosphere. Pyrolysis plants can be used for work with tubular reactors anywhere. Due to them farmers can dry grain, using waste heat of diesel generators, heatgenerators, boiler plants and receiving thus gaseous products, liquid and firm fractions. A technology based on cyclic and continuous plant mass movement by a piston in a pipe from a loading site to a place of unloading of a firm phase consistently through cameras of drying, pyrolysis, condensation of gaseous products. Exhaust furnace gases with a temperature up to 600 degrees Celsius are given countercurrent material movement from a power equipment. The gaseous, liquid and firm products from the pyrolysis camera are used for heat and electric power generation. Calculation of parameters of subdrying and pyrolysis cameras is necessary for effective and steady operation of the tubular reactor. The authors determined the speed of raw materials movement, and also duration of drying and pyrolysis in working chambers. An analysis of a simplified mathematical model of process was confirmed with results of experiments. Models of heat treatment of wet plant materials in tubular reactors are worked out on a basis of equality of speeds of material movement in the reactor and distribution of a temperature front in material on radius. The authors defined estimated characteristic for determination of tubular reactor productivity and size of heat, required for drying and pyrolysis.

Excreted/secreted Trichuris suis products reduce barrier function and suppress inflammatory cytokine production of intestinal epithelial cells

DEFF Research Database (Denmark)

Hiemstra, I. H.; Klaver, E. J.; Vrijland, K.

2014-01-01

The administration of helminths is considered a promising strategy for the treatment of autoimmune diseases due to their immunomodulatory properties. Currently, the application of the helminth Trichuris suis as a treatment for Crohn's disease is being studied in large multi-center clinical trials....... The intestinal epithelium forms an efficient barrier between the intestinal lumen containing the microbial flora and helminths, and dendritic cells (DCs) present in the lamina propria that determine the TH response. Here, we investigated how excreted/secreted (E/S) products of T. suis affect the barrier function...... of intestinal epithelial cells (IECs) in order to reach the DCs and modulate the immune response. We show that T. suis E/S products reduce the barrier function and the expression of the tight junction proteins EMP-1 and claudin-4 in IEC CMT93/69 monolayers in a glycan-dependent manner. This resulted...

Nonimaging secondary concentrators for large rim angle parabolic troughs with tubular absorbers.

Science.gov (United States)

Ries, H; Spirkl, W

1996-05-01

For parabolic trough solar collectors with tubular absorbers, we design new tailored secondary concentrators. The design is applicable for any rim angle of a parabolic reflector. With the secondary, the concentration can be increased by a factor of more than 2 with a compact secondary reflector consisting of a single piece, even for the important case of a rim angle of 90 deg. The parabolic reflector can be used without changes; the reduced absorber is still tubular but smaller than the original absorber and slightly displaced toward the primary.

Distal renal tubular acidosis and hypokalemic paralysis in a patient with hypothyroidism

Directory of Open Access Journals (Sweden)

Parvaiz Ahmad Koul

2011-01-01

Full Text Available A 43- year- old woman on treatment for primary hypothyroidism presented with 1- day progressive weakness of all her limbs and history of similar episodes in the past. Clinical examination revealed grade 2 hyporeflexive weakness. Investigations revealed features of hypokalemia, metabolic acidosis, alkaline urine, and a fractional bicarbonate excretion of 3.5%, consistent with distal renal tubular acidosis. Antithyroid peroxidase and antithroglobulin antibodies were positive, suggesting an autoimmune basis for the pathogenesis of the functional tubular defect. Bicarbonate therapy resulted in a sustained clinical recovery.

Tubular forms of papova viruses in human laryngeal papilloma.

Science.gov (United States)

Arnold, W

1979-01-01

In two cases of recurrent laryngeal papillomatosis tubular forms of papova viruses could be observed. The same material revealed the close relation between nuclear chromatine and the release of particles, as well as a capsomere like substructure of the virions.

Tubular closure mechanism

International Nuclear Information System (INIS)

Kalen, D.D.; Mitchem, J.W.

1981-01-01

An apparatus is provided for closing the bore of a tube and releasably securing articles within the tube under longitudinal load. A latching member has a cylindrical section and several circumferentially-spaced elongated latches hanging down from one end of the cylinder. An elongated actuator has integral cam and spline and is partly located within the latch with the cam radially contacting the latches and the spline projecting into the circumferential spaces between the latches. The actuator is axially movable between a position in which the latches are locked to the tube walls and a position in which the latches are secured from contact with the tube walls. Means are provided for axially moving the actuator such that the cam positions the latches; and means are also provided for engaging the articles within the tube. The closure is particularly applicable to tubular irradiation surveillance specimen assembly holders used in reactors

Schottky barrier enhancement on n-InP solar cell applications

DEFF Research Database (Denmark)

Clausen, Thomas; Leistiko, Otto

1994-01-01

It is demonstrated that the Schottky barrier height on n-type InP can be enhanced to values close to the energy bandgap (1.35 eV) by employing a AuZnCr metallization. The process is simple and requires only mild and fast annealing sequences with temperatures not exceeding 500°C. Also, no critical...... epitaxial growth step of junctions is needed, making the process fairly cheap. Thus, prospects for an efficient and simple solar cell device structure for space application purposes based on highly radiant-resistant InP are greatly improved...

Characterization of Chiral Carbonaceous Nanotubes Prepared from Four Coiled Tubular 4,4'-biphenylene-silica Nanoribbons

Directory of Open Access Journals (Sweden)

Shuwei Lin

2014-04-01

Full Text Available Four dipeptides derived from phenylalanine were synthesized, which can self-assemble into twisted nanoribbon in deionized water. The handedness of the organic self-assemblies was controlled by the chirality of the phenylalanine at the terminals. Coiled 4,4'-biphenylene bridged polybissilsesquioxane tubular nanoribbons were prepared using the organic self-assemblies as the templates. The circular dichroism spectra indicated that the biphenylene rings preferred to twist in one-handedness within the walls of the samples. After carbonization and removal of silica, single-handed coiled carbonaceous tubular nanoribbons were obtained. The Raman spectra indicated that the carbon was amorphous. The diffuse reflectance circular dichroism spectra indicated the tubular carbonaceous nanoribbons exhibited optical activity.

Structure and barrier properties of human embryonic stem cell-derived retinal pigment epithelial cells are affected by extracellular matrix protein coating.

Science.gov (United States)

Sorkio, Anni; Hongisto, Heidi; Kaarniranta, Kai; Uusitalo, Hannu; Juuti-Uusitalo, Kati; Skottman, Heli

2014-02-01

Extracellular matrix (ECM) interactions play a vital role in cell morphology, migration, proliferation, and differentiation of cells. We investigated the role of ECM proteins on the structure and function of human embryonic stem cell-derived retinal pigment epithelial (hESC-RPE) cells during their differentiation and maturation from hESCs into RPE cells in adherent differentiation cultures on several human ECM proteins found in native human Bruch's membrane, namely, collagen I, collagen IV, laminin, fibronectin, and vitronectin, as well as on commercial substrates of xeno-free CELLstart™ and Matrigel™. Cell pigmentation, expression of RPE-specific proteins, fine structure, as well as the production of basal lamina by hESC-RPE on different protein coatings were evaluated after 140 days of differentiation. The integrity of hESC-RPE epithelium and barrier properties on different coatings were investigated by measuring transepithelial resistance. All coatings supported the differentiation of hESC-RPE cells as demonstrated by early onset of cell pigmentation and further maturation to RPE monolayers after enrichment. Mature RPE phenotype was verified by RPE-specific gene and protein expression, correct epithelial polarization, and phagocytic activity. Significant differences were found in the degree of RPE cell pigmentation and tightness of epithelial barrier between different coatings. Further, the thickness of self-assembled basal lamina and secretion of the key ECM proteins found in the basement membrane of the native RPE varied between hESC-RPE cultured on compared protein coatings. In conclusion, this study shows that the cell culture substrate has a major effect on the structure and basal lamina production during the differentiation and maturation of hESC-RPE potentially influencing the success of cell integrations and survival after cell transplantation.

Miniature Dielectric Barrier Discharge Nonthermal Plasma Induces Apoptosis in Lung Cancer Cells and Inhibits Cell Migration.

Science.gov (United States)

Karki, Surya B; Yildirim-Ayan, Eda; Eisenmann, Kathryn M; Ayan, Halim

2017-01-01

Traditional cancer treatments like radiotherapy and chemotherapy have drawbacks and are not selective for killing only cancer cells. Nonthermal atmospheric pressure plasmas with dielectric barrier discharge (DBD) can be applied to living cells and tissues and have emerged as novel tools for localized cancer therapy. The purpose of this study was to investigate the different effects caused by miniature DBD (mDBD) plasma to A549 lung cancer cells. In this study, A549 lung cancer cells cultured in 12 well plates were treated with mDBD plasma for specified treatment times to assess the changes in the size of the area of cell detachment, the viability of attached or detached cells, and cell migration. Furthermore, we investigated an innovative mDBD plasma-based therapy for localized treatment of lung cancer cells through apoptotic induction. Our results indicate that plasma treatment for 120 sec causes apoptotic cell death in 35.8% of cells, while mDBD plasma treatment for 60 sec, 30 sec, or 15 sec causes apoptotic cell death in 20.5%, 14.1%, and 6.3% of the cell population, respectively. Additionally, we observed reduced A549 cell migration in response to mDBD plasma treatment. Thus, mDBD plasma system can be a viable platform for localized lung cancer therapy.

Miniature Dielectric Barrier Discharge Nonthermal Plasma Induces Apoptosis in Lung Cancer Cells and Inhibits Cell Migration

Directory of Open Access Journals (Sweden)

Surya B. Karki

2017-01-01

Full Text Available Traditional cancer treatments like radiotherapy and chemotherapy have drawbacks and are not selective for killing only cancer cells. Nonthermal atmospheric pressure plasmas with dielectric barrier discharge (DBD can be applied to living cells and tissues and have emerged as novel tools for localized cancer therapy. The purpose of this study was to investigate the different effects caused by miniature DBD (mDBD plasma to A549 lung cancer cells. In this study, A549 lung cancer cells cultured in 12 well plates were treated with mDBD plasma for specified treatment times to assess the changes in the size of the area of cell detachment, the viability of attached or detached cells, and cell migration. Furthermore, we investigated an innovative mDBD plasma-based therapy for localized treatment of lung cancer cells through apoptotic induction. Our results indicate that plasma treatment for 120 sec causes apoptotic cell death in 35.8% of cells, while mDBD plasma treatment for 60 sec, 30 sec, or 15 sec causes apoptotic cell death in 20.5%, 14.1%, and 6.3% of the cell population, respectively. Additionally, we observed reduced A549 cell migration in response to mDBD plasma treatment. Thus, mDBD plasma system can be a viable platform for localized lung cancer therapy.

Hot Firing of a Full Scale Copper Tubular Combustion Chamber

National Research Council Canada - National Science Library

Cooley, C

2002-01-01

This paper describes the chamber design and hot firing test results for a full-scale copper tubular combustion chamber that has future application in a high-thrust, upper-stage expander cycle engine...

Telmisartan, a possible PPAR-δ agonist, reduces TNF-α-stimulated VEGF-C production by inhibiting the p38MAPK/HSP27 pathway in human proximal renal tubular cells

Energy Technology Data Exchange (ETDEWEB)

Kimura, Hideki, E-mail: hkimura@u-fukui.ac.jp [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Department of Clinical Laboratories and Nephrology, University of Fukui Hospital, Fukui (Japan); Mikami, Daisuke; Kamiyama, Kazuko [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Sugimoto, Hidehiro [Department of Clinical Laboratories and Nephrology, University of Fukui Hospital, Fukui (Japan); Kasuno, Kenji; Takahashi, Naoki [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Yoshida, Haruyoshi [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan); Division of Nephrology, Obama Municipal Hospital, Obama, Fukui (Japan); Iwano, Masayuki [Division of Nephrology, Department of General Medicine, School of Medicine, Faculty of Medical Sciences, University of Fukui, Fukui (Japan)

2014-11-14

Highlights: • TNF-α increased VEGF-C expression by enhancing phosphorylation of p38MAPK and HSP27. • Telmisartan decreased TNF-α-stimulated expression of VEGF-C. • Telmisartan suppressed TNF-α-induced phosphorylation of p38MAPK and HSP27. • Telmisartan activated endogenous PPAR-δ protein. • Telmisartan suppressed p38MAPK phosphorylation in a PPAR-δ-dependent manner. - Abstract: Vascular endothelial growth factor-C (VEGF-C) is a main inducer of inflammation-associated lymphangiogenesis in various inflammatory disorders including chronic progressive kidney diseases, for which angiotensin II receptor type 1 blockers (ARBs) are widely used as the main treatment. Although proximal renal tubular cells may affect the formation of lymphatic vessels in the interstitial area by producing VEGF-C, the molecular mechanisms of VEGF-C production and its manipulation by ARB have not yet been examined in human proximal renal tubular epithelial cells (HPTECs). In the present study, TNF-α dose-dependently induced the production of VEGF-C in HPTECs. The TNF-α-induced production of VEGF-C was mediated by the phosphorylation of p38MAPK and HSP27, but not by that of ERK or NFkB. Telmisartan, an ARB that can activate the peroxisome proliferator-activated receptor (PPAR), served as a PPAR-δ activator and reduced the TNF-α-stimulated production of VEGF-C. This reduction was partially attributed to a PPAR-δ-dependent decrease in p38MAPK phosphorylation. Our results indicate that TNF-α induced the production of VEGF-C in HPTECs by activating p38MAPK/HSP27, and this was partially inhibited by telmisartan in a PPAR-δ dependent manner. These results provide a novel insight into inflammation-associated lymphangiogenesis.

Comparison of four decontamination treatments on porcine renal decellularized extracellular matrix structure, composition, and support of human renal cortical tubular epithelium cells.

Science.gov (United States)

Poornejad, Nafiseh; Nielsen, Jeffery J; Morris, Ryan J; Gassman, Jason R; Reynolds, Paul R; Roeder, Beverly L; Cook, Alonzo D

2016-03-01

Engineering whole organs from porcine decellularized extracellular matrix and human cells may lead to a plentiful source of implantable organs. Decontaminating the porcine decellularized extracellular matrix scaffolds is an essential step prior to introducing human cells. However, decontamination of whole porcine kidneys is a major challenge because the decontamination agent or irradiation needs to diffuse deep into the structure to eliminate all microbial contamination while minimizing damage to the structure and composition of the decellularized extracellular matrix. In this study, we compared four decontamination treatments that could be applicable to whole porcine kidneys: 70% ethanol, 0.2% peracetic acid in 1 M NaCl, 0.2% peracetic acid in 4% ethanol, and gamma (γ)-irradiation. Porcine kidneys were decellularized by perfusion of 0.5% (w/v) aqueous solution of sodium dodecyl sulfate and the four decontamination treatments were optimized using segments (n = 60) of renal tissue to ensure a consistent comparison. Although all four methods were successful in decontamination, γ-irradiation was very damaging to collagen fibers and glycosaminoglycans, leading to less proliferation of human renal cortical tubular epithelium cells within the porcine decellularized extracellular matrix. The effectiveness of the other three optimized solution treatments were then all confirmed using whole decellularized porcine kidneys (n = 3). An aqueous solution of 0.2% peracetic acid in 1 M NaCl was determined to be the best method for decontamination of porcine decellularized extracellular matrix. © The Author(s) 2015.

The Flavonoid Apigenin Ameliorates Cisplatin-Induced Nephrotoxicity through Reduction of p53 Activation and Promotion of PI3K/Akt Pathway in Human Renal Proximal Tubular Epithelial Cells

Directory of Open Access Journals (Sweden)

Sung Min Ju

2015-01-01

Full Text Available Apigenin is a member of the flavone subclass of flavonoids present in fruits and vegetables. Apigenin has long been considered to have various biological activities, such as antioxidant, anti-inflammatory, and antitumorigenic properties, in various cell types. Cisplatin was known to exhibit cytotoxic effect to renal cells by inducing apoptosis through activation of p53. The present study investigated the antiapoptotic effects of apigenin on the cisplatin-treated human renal proximal tubular epithelial (HK-2 cells. HK-2 cells were pretreated with apigenin (5, 10, 20 μM for 1 h and then treated with 40 μM cisplatin for various times. Apigenin inhibited the cisplatin-induced apoptosis of HK-2 cells. Interestingly, apigenin itself exerted cytostatic activity because of its ability to induce cell cycle arrest. Apigenin inhibited caspase-3 activity and PARP cleavage in cisplatin-treated cells. Apigenin reduced cisplatin-induced phosphorylation and expression of p53, with no significant influence on production of ROS that is known to induce p53 activation. Furthermore, apigenin promoted cisplatin-induced Akt phosphorylation, suggesting that enhanced Akt activation may be involved in cytoprotection. Taken together, these results suggest that apigenin ameliorates cisplatin-induced apoptosis through reduction of p53 activation and promotion of PI3K/Akt pathway in HK-2 cells.

Modeling of Unidirectional-Overloaded Transition in Catalytic Tubular Microjets

NARCIS (Netherlands)

Klingner, Anke; Khalil, Islam S. M.; Magdanz, Veronika; Fomin, Vladimir M.; Schmidt, Oliver G.; Misra, Sarthak

2017-01-01

A numerical time-resolved model is presented for predicting the transition between unidirectional and overloaded motion of catalytic tubular microjets (Ti/Fe/Pt rolled-up microtubes) in an aqueous solution of hydrogen peroxide. Unidirectional movement is achieved by periodic ejection of gas bubbles

Torsional stresses in the transverse fillet weld tubular joints

NARCIS (Netherlands)

Gunay, D.; Aydemir, A.; Özer, H.

1996-01-01

Torsional stresses, 'tre and tel , in tbe transverse fillet tubular weld joint subjected to torsional load have been analyzed by the finite element method using triangular and quadrilateral izoparametric axisymmetric fourier type torus finite elements. There is an axisymmetry with respect to

Rocket-inspired tubular catalytic microjets with grating-structured walls as guiding empennages.

Science.gov (United States)

Huang, Gaoshan; Wang, Jiyuan; Liu, Zhaoqian; Zhou, Dekai; Tian, Ziao; Xu, Borui; Li, Longqiu; Mei, Yongfeng

2017-12-07

Controllable locomotion in the micro-/nanoscale is challenging and attracts increasing research interest. Tubular microjets self-propelled by microbubbles are intensively investigated due to their high energy conversion efficiency, but the imperfection of the tubular geometry makes it harder to realize linear motion. Inspired by the macro rocket, we designed a tubular microjet with a grating-structured wall which mimics the guiding empennage of the macro rocket, and we found that the fluid can be effectively guided by the grooves. Both theoretical simulation and experimental work have been carried out, and the obtained results demonstrate that the stability margin of the grating-structured microjet can be enhanced. Compared with microjets with smooth walls, the structured microjets show an enhanced ability of moving linearly. In 10% H 2 O 2 , only 20% of the smooth microjets demonstrate linear trajectories, while 80% of the grating-structured microjets keep moving straight. The grating-structured microjet can maintain linear motion under external disturbance. We further propose to increase the stability by introducing a helical grating structure.

Connecting small ligands to generate large tubular metal-organic architectures

International Nuclear Information System (INIS)

Goforth, Andrea M.; Su, Cheng-Yong; Hipp, Rachael; Macquart, Rene B.; Smith, Mark D.; Loye, Hans-Conrad zur

2005-01-01

The new metal-organic framework materials, ZnF(Am 2 TAZ).solvents and ZnF(TAZ).solvents (Am 2 TAZ=3,5-diamino-1,2,4-triazole, TAZ=1,2,4-triazole), have been synthesized solvothermally and structurally characterized by either Rietveld refinement from powder XRD data or by single crystal X-ray diffraction. The three-dimensional structures of the compounds display open-ended, tubular channels, which are constituted of covalently bonded hexanuclear metallamacrocycles (Zn 6 F 6 (ligand) 6 ). The tubular channels are subsequently covalently joined into a honeycomb-like hexagonal array to generate the three-dimensional porous framework. In the case of ZnF(Am 2 TAZ).solvents, hydrophilic -NH 2 groups point into the channels, effectively reducing their inner diameter relative to ZnF(TAZ).solvents. The present compounds are isostructural to one another and to the previously reported ZnF(AmTAZ).solvents (AmTAZ=3-amino-1,2,4-triazole), illustrative of the fact that the internal size and chemical properties of the framework may be altered by modification of the small, heterocyclic ligand. In addition to demonstrating the ability to modify the basic framework, ZnF(TAZ).solvents and ZnF(Am 2 TAZ).solvents are two of the most thermally stable coordination frameworks known to date. - Graphical abstract: Top view of the open-ended, honeycomb tubular architecture of ZnF(Am 2 TAZ)

Nitrogen- and oxygen-enriched carbon with square tubular structure prepared from polyaniline as electrode for supercapacitors

Energy Technology Data Exchange (ETDEWEB)

Xiang, X.; Liu, E.; Wu, Y.; Tian, Y.; Xie, H.; Wu, Z.; Zhu, Y. [Key Laboratory of Environmentally Friendly Chemistry and Applications of Ministry of Education, College of Chemistry, Xiangtan University, Hunan (China)

2012-10-15

Square tubular carbon with a large number of surface functional groups are prepared by carbonizing and activating polyaniline, which are synthesized by polymerization of aniline with a template-free self-assembly method in aqueous media. The physicochemical properties of the square tubular carbon is characterized by scanning and transmission electron microscopy, Brunauer-Emmett-Teller surface area measurements, Raman spectroscopy, and X-ray photoelectron spectroscopy measurements. When used as an electrode, the square tubular carbon exhibit a specific capacitance of 223 F g{sup -1} at a scan rate of 2 mV s{sup -1}, which could still stay over 90% when the scan rate increased by 10 times. The specific capacitance even hardly decrease at a current density of 3 A g{sup -1} after 10,000 cycles, which indicates that the square tubular carbon have good cycle durability and may be a promising candidate as an electrode for supercapacitors. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

In vitro models of the blood–brain barrier: An overview of commonly used brain endothelial cell culture models and guidelines for their use

Science.gov (United States)

Helms, Hans C; Abbott, N Joan; Burek, Malgorzata; Cecchelli, Romeo; Couraud, Pierre-Olivier; Deli, Maria A; Förster, Carola; Galla, Hans J; Romero, Ignacio A; Shusta, Eric V; Stebbins, Matthew J; Vandenhaute, Elodie; Weksler, Babette

2016-01-01

The endothelial cells lining the brain capillaries separate the blood from the brain parenchyma. The endothelial monolayer of the brain capillaries serves both as a crucial interface for exchange of nutrients, gases, and metabolites between blood and brain, and as a barrier for neurotoxic components of plasma and xenobiotics. This “blood-brain barrier” function is a major hindrance for drug uptake into the brain parenchyma. Cell culture models, based on either primary cells or immortalized brain endothelial cell lines, have been developed, in order to facilitate in vitro studies of drug transport to the brain and studies of endothelial cell biology and pathophysiology. In this review, we aim to give an overview of established in vitro blood–brain barrier models with a focus on their validation regarding a set of well-established blood–brain barrier characteristics. As an ideal cell culture model of the blood–brain barrier is yet to be developed, we also aim to give an overview of the advantages and drawbacks of the different models described. PMID:26868179

Efecto citotóxico de la toxina shiga tipo 2 y su subunidad b en células epiteliales tubulares renales humanas en cultivo Cytotoxic effect of Shiga toxin type 2 and its B subunit on human renal tubular epithelial cell cultures

Directory of Open Access Journals (Sweden)

Virginia Pistone Creydt

2005-04-01