bluuebunny/crossref_metadata_2025_split huggingface dataset:
Utilizing acid pretreatment and electrospinning to improve biocompatibility of poly(glycolic acid) for tissue engineering
Authors: Boland Eugene D. , Telemeco Todd A. , Simpson David G. , Wnek Gary E. , Bowlin Gary L. 
Published: June 2004

AbstractPoly(glycolic acid) (PGA) has a long history as a bioresorbable polymer. Its biocompatibility is widely accepted, yet PGA is often rejected as a soft‐tissue scaffold because of fibrous encapsulation. The goal of this study was to improve the soft‐tissue biocompatibility of PGA by producing scaffolds composed of small‐diameter fibers through electrospinning and subjecting these scaffolds to a concentrated hydrochloric acid (HCL) pretreatment. The theory is that small‐diameter fibers will elicit a reduced immune response and HCl treatment will improve cellular interactions. Scaffolds were characterized in terms of fiber diameter and pore area via image‐analysis software. Biocompatibility was assessed through a WST‐1 cell‐proliferation assay (in vitro) with the use of rat cardiac fibroblasts and rat intramuscular implantations (in vivo). Fibers produced ranged in diameter from 0.22 to 0.88 μm with pore areas from 1.84 to 13.22 μm2. The untreated scaffold composed of 0.88‐μm fibers was encapsulated in vivo and supported the lowest rates of cell proliferation. On the contrary, the acid pretreated scaffold with 0.22‐μm fibers was incorporated into the surrounding tissue and exhibited proliferation rates that exceeded the control populations on tissue‐culture plastic. In conclusion, this study has shown the ability to improve the biocompatibility of PGA through acid pretreatment of scaffolds comprised of submicron fiber diameters. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 71B: 144–152, 2004
Lysophosphatidic acid production and action: Validated targets in cancer?
Authors: Umezu‐Goto Makiko , Tanyi Janos , Lahad John , Liu Shuying , Yu Shuangxing , Lapushin Ruth , Hasegawa Yutaka , Lu Yiling , Trost Rosanne , Bevers Therese , Jonasch Eric , Aldape Ken , Liu Jinsong , James Robyn D. , Ferguson Colin G. , Xu Yong , Prestwich Glenn D. , Mills Gordon B. 
Published: June 2004

AbstractThe completion of the human genome project, the evolution of transcriptional profiling and the emergence of proteomics have focused attention on these areas in the pathophysiology and therapy of cancer. The role of lysophospholipids as potential mediators in cancer pathophysiology, screening and management has taken a major leap forward with the recent cloning of several enzymes involved in the metabolism of lysophospholipids. Lysophospholipids, although small molecules, contain a high “informational” content. Differences include the nature of the phosphate head group, the regiochemistry of the fatty acyl chain on the glyceryl backbone, the presence of ether versus ester linkages to the backbone, and the length and saturation of the fatty acyl or alkyl chain. This informational content is sufficient to result in a marked structure function activity relationship at their cognate receptors. Thus the emerging discipline of “functional lipidomics” is likely to prove as important as genomics and proteomics in terms of early diagnosis, prognosis, and therapy. Lysophospholipid levels are elevated in vivo in a number of pathophysiological states including ascitic fluid from ovarian cancer patients indicating a role in the pathophysiology of this devastating disease. Although controversial, levels of specific lysophospholipids may be altered in the blood of cancer patients providing a potential mechanism for early diagnosis. Several of the enzymes involved in the metabolism of lysophospholipids are aberrant in ovarian and other cancers. Further, the enzymes are active in the interstitial space, rendering them readily accessible to the effects of inhibitors including antibodies, proteins, and small molecules. In support of a role for lysophospholipids in the pathophysiology of cancer, expression of receptors for lysophospholipids is also aberrant in cancer cells from multiple different lineages. All of the cell surface receptors for lysophospholipids belong to the G protein coupled receptor family. As over 40% of all drugs in current use target this family of receptors, lysophospholipid receptors are highly “druggable.” Indeed, a number of highly specific agonists and antagonists of lysophospholipid receptors have been identified. A number are in preclinical evaluation as therapeutics. We look forward to the next several years when the role of lysophospholipids in physiology and the pathophysiology and management of cancer and other diseases are fully elucidated. © 2004 Wiley‐Liss, Inc.
L‐ascorbic acid represses constitutive activation of NF‐κB and COX‐2 expression in human acute myeloid leukemia, HL‐60
Authors: Han Seong‐Su , Kim Kihyun , Hahm Eun‐Ryeong , Lee Sook J. , Surh Young‐Joon , Park Hye K. , Kim Won S. , Jung Chul W. , Lee Mark H. , Park Keunchil , Yang Jung‐Hyun , Yoon Sung‐Soo , Riordan Neil H. , Riordan Hugh D. , Kimler Bruce F. , Park Chan H. , Lee Je‐Ho , Park Seyeon 
Published: June 2004

AbstractThere is increasing evidence that l‐ascorbic acid (LAA) is selectively toxic to some types of cancer cells at pharmacological concentrations, functioning as a pro‐oxidant rather than as an anti‐oxidant. However, the molecular mechanisms by which LAA initiates cellular signaling leading to cell death are still unclear. In an effort to gain insight into these mechanisms, the effects of LAA on eukaryotic transcription nuclear factor NF‐κB and cyclooxygenase‐2 (COX‐2) expression were investigated. In the present study, LAA suppressed DNA binding activity of NF‐κB, composed of a p65/p50 heterodimer, through inhibition of degradation of inhibitory κB‐α (IκB‐α) and prevention of nuclear translocation of p65. The inhibitory effect of LAA on NF‐κB activity was dependent upon glutathione levels in HL‐60 cells, as well as generation of H2O2 but not superoxide anion. LAA also downregulated the expression of COX‐2, which has a NF‐κB binding site on its promoter, through repressing NF‐κB DNA binding activity. Moreover, cotreatment of 1 μM arsenic trioxide (As2O3) with various concentrations of LAA enhanced an LAA‐induced repression of NF‐κB activity and COX‐2 expression. In conclusion, our data suggest that LAA exerts its anti‐tumor activity through downregulation of NF‐κB activity and COX‐2 expression, and these inhibitory effects can be enhanced by co‐treatment with As2O3. © 2004 Wiley‐Liss, Inc.
Effects of hydrogen peroxide on MAPK activation, IL‐8 production and cell viability in primary cultures of human bronchial epithelial cells
Authors: Pelaia Girolamo , Cuda Giovanni , Vatrella Alessandro , Gallelli Luca , Fratto Donatella , Gioffrè Vincenza , D'Agostino Bruno , Caputi Mario , Maselli Rosario , Rossi Francesco , Costanzo Francesco S. , Marsico Serafino A. 
Published: June 2004

AbstractThe airway epithelium is continuously exposed to inhaled oxidants, including airborne pollutants and cigarette smoke, which can exert harmful proinflammatory and cytotoxic effects. Therefore, the aim of our study was to investigate, in primary cultures of human bronchial epithelial cells (HBEC), the signal transduction pathways activated by increasing concentrations (0.25, 0.5, and 1 mM) of hydrogen peroxide (H2O2), as well as their effects on IL‐8 production and cell viability. The reported results show that H2O2 elicited, in a concentration‐dependent fashion, a remarkable increase in phosphorylation‐dependent activation of mitogen‐activated protein kinases (MAPKs), associated with a significant induction of IL‐8 synthesis and a dramatically enhanced cell death. Pre‐treatment of HBEC with MAPK inhibitors was able to significantly inhibit the effects of H2O2 on IL‐8 secretion, and to effectively prevent cell death. Therefore, these findings suggest that MAPKs play a key role as molecular transducers of the airway epithelial injury triggered by oxidative stress, as well as potential pharmacologic targets for indirect antioxidant intervention. © 2004 Wiley‐Liss, Inc.
Hypoxia‐induced erythropoietin expression in human neuroblastoma requires a methylation free HIF‐1 binding site
Authors: Rössler Jochen , Stolze Ineke , Frede Stilla , Freitag Patricia , Schweigerer Lothar , Havers Werner , Fandrey Joachim 
Published: June 2004

AbstractThe glycoprotein hormone Erythropoietin (EPO) stimulates red cell production and maturation. EPO is produced by the kidneys and the fetal liver in response to hypoxia (HOX). Recently, EPO expression has also been observed in the central nervous system where it may be neuroprotective. It remained unclear, however, whether EPO is expressed in the peripheral nervous system and, if so, whether a neuronal phenotype is required for its regulation. Herein, we report that EPO expression was induced by HOX and a HOX mimetic in two cell lines derived from neuroblastoma (NB), a tumor of the peripheral nervous system. Both cell lines with inducible EPO expression, SH‐SY5Y and Kelly cells, expressed typical neuronal markers like neuropeptide Y (NPY), growth‐associated protein‐43 (GAP‐43), and neuron‐specific enolase (ENO). NB cells with a more epithelial phenotype like SH‐SHEP and LAN‐5 did not show HOX inducible EPO gene regulation. Still, oxygen sensing and up‐regulation of hypoxia‐inducible factor‐1 (HIF‐1) were intact in all cell lines. We found that CpG methylation of the HIF binding site (HBS) in the EPO gene 3′ enhancer was only present in the SH‐SHEP and LAN‐5 cells but not in SH‐SY5Y and Kelly cells with regulated EPO expression. The addition of recombinant EPO to all NB cells, both under normoxic and hypoxic conditions, had no effect on cell proliferation. We conclude that the ability to respond to HOX with an increase in EPO expression in human NB may depend on CpG methylation and the differentiation status of these embryonic tumor cells but does not affect the proliferative characteristics of the cells. © 2004 Wiley‐Liss, Inc.
Paeoniflorin induces apoptosis of lymphocytes through a redox‐linked mechanism
Authors: Tsuboi Hideo , Hossain Khaled , Akhand Anwarul A. , Takeda Kozue , Du Jun , Rifa'i Muhaimin , Dai Yan , Hayakawa Akemi , Suzuki Haruhiko , Nakashima Izumi 
Published: June 2004

AbstractPaeoniflorin (PF), isolated from paeony root, has been used as a herbal medicine for more than 1,200 years in China, Korea, and Japan for its anti‐allergic, anti‐inflamatory, and immunoregulatory effects. In this study, we found that PF induces apoptosis in both murine T‐lineage cells and human T‐cell leukemia Jurkat cells. This apoptosis was mediated through the reduction of mitochondrial membrane potential, activation of caspase, and fragmentation of DNA. Interestingly, PF induced generation of reactive oxygen species (ROS) and a reducing agent, dithiothreitol (DTT), and a ROS scavenger, N‐acetyl cysteine (NAC), successfully attenuated the PF‐induced apoptosis. Additionally, PF induced the phosphorylation of three mitogen‐activated protein (MAP) family kinases, extracellular signal‐regulated kinase, c‐Jun amino‐terminal kinase (JNK), and p38 MAP kinase. Curcumin, an anti‐oxidant and JNK inhibitor, inhibited PF‐induced apoptosis, suggesting the possible involvement of curcumin‐sensitive JNK or other redox‐sensitive elements in PF‐induced apoptosis. These results partially explain the action mechanism of PF‐containing paeony root as a herbal medicine. © 2004 Wiley‐Liss, Inc.
Homocysteine induces metalloproteinase and shedding of β‐1 integrin in microvessel endothelial cells
Authors: Shastry Suresh , Tyagi Suresh C. 
Published: June 2004

AbstractAlthough studies have suggested microvessel endothelial cells (MVEC) activation and induction of matrix metalloproteinases (MMPs) by homocysteine (Hcy), the transduction mechanism leading to endothelial activation was unclear. We hypothesized that Hcy induced metalloproteinase and altered the levels of integrin in MVEC. MVEC from mouse brain were isolated and characterized by CD‐31 (PECAM‐1) FITC labeling. The MVEC were activated with different doses (6–40 μM) of Hcy. The cultured‐conditioned‐medium was analyzed for MMP activity by gelatin gel‐zymography. TIMP‐1, ‐4, β‐1 integrin, and a disintegrin and metalloproteinase‐12 (ADAM‐12) were quantified by Western blot analysis. We used MVEC in cell culture to study the effect of increasing concentrations of Hcy upon the secretion of various proteins into the culture medium. MMP‐9, β‐1 integrin, ADAM‐12, and TIMP‐1 were found in increased concentrations in the culture medium of Hcy‐treated cells whereas TIMP‐4 was decreased. We have shown that purified TIMP‐4 blocked the increase of β‐1 integrin shedding in Hcy‐treated cells. Interestingly, our results suggest that TIMP‐1 and TIMP‐4 function antagonistically in Hcy‐induced signaling pathways. © 2004 Wiley‐Liss, Inc.
Vitamin D3 modulated gene expression patterns in human primary normal and cancer prostate cells
Authors: Guzey Meral , Luo Jianhua , Getzenberg Robert H. 
Published: June 2004

AbstractThe vitamin D receptor (VDR) is a member of the steroid/retinoid receptor superfamily of nuclear receptors and has potential tumor‐suppressive functions in prostate and other cancer types. Vitamin D3 (VD3) exerts its biological actions by binding within cells to VDR. The VDR then interacts with specific regions of the DNA in cells, and triggers changes in the activity of genes involved in cell division, cell survival, and cellular function. Using human primary cultures and the prostate cancer (PCa) cell line, ALVA‐31, we examined the effects of VD3 under different culture conditions. Complete G0/G1 arrest of ALVA‐31 cells and ∼50% inhibition of tumor stromal cell growth was observed. To determine changes in gene expression patterns related to VD3 activity, microarray analysis was performed. More than ∼20,000 genes were evaluated for twofold relative increases and decreases in expression levels. A number of the gene targets that were up‐ and down‐regulated are related to potential mechanisms of prostatic growth regulation. These include estrogen receptor (ER), heat shock proteins: 70 and 90, Apaf1, Her‐2/neu, and paxillin. Utilizing antibodies generated against these targets, we were able to confirm the changes at the protein level. These newly reported gene expression patterns provide novel information not only potential markers, but also on the genes involved in VD3 induced apoptosis in PCa. © 2004 Wiley‐Liss, Inc.
Analysis of discontinuities in rectangular ducts and higher order mode excitations using TLM and FEM methods
Authors: El‐Masri Samir 
Published: June 2004

AbstractIn acoustic waveguide, it is believed that higher order modes have a dramatic effect on the behaviour of the global acoustic waves when the frequency of the source is above the cut‐off frequency of the duct. In this paper, we are going to study the influence of the discontinuities on the excitation and the propagation of higher order modes in symmetrical and non‐symmetrical ducts using theoretical analysis and numerical simulations. As for numerical simulations, transmission line matrix (TLM) method and finite element method (FEM) will be used. Moreover, we will try here to compare the two numerical methods, showing their advantages and disadvantages. The transfer functions of symmetrical and non‐symmetrical ducts will also be shown and discussed as well as numerical simulations of the acoustic pressure into the duct in three‐dimensional (3‐D) system. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of the optimum tilt of a PV array using maximum global insolation technique
Authors: Nafeh Abd El‐Shafy A. 
Published: June 2004

AbstractThe photovoltaic (PV) is considered to be the most promising energy source in many applications, due to its safety and high reliability. But the initial high cost of the PV arrays and the large areas necessitate their optimum use. One of the solutions that optimizes the array performance is to what extent the array tilt should be adjusted such that the incident insolation on the array becomes as large as possible. In this paper, a new technique, which maximizes the incident solar insolation at solar noon on the tilted PV array, is proposed and developed. The monthly mean values of the solar insolation incident on a horizontal surface is calculated using a statistical methods. Also, a comparison between the proposed technique and the most common one is studied. The results indicate the superiority of the proposed technique. Copyright © 2004 John Wiley & Sons, Ltd.
Physically based 2D compact model for power bipolar devices
Authors: Igic P. M. , Towers M. S. , Mawby P. A. 
Published: June 2004

AbstractThe two‐dimensional (2D) physical compact model for advanced power bipolar devices such as injection enhanced gate transistor (IEGT) or Trench IGBT is presented in this paper. In order to model the complex 2D nature of these devices the ambipolar diffusion equation has been solved simultaneously for different boundary conditions associated with different areas of the device. The IEGT compact model has been incorporated into the SABER simulator and tested in standard double‐pulse switching test circuit. The compact model has been established to model a 4500V‐1500A flat pack TOSHIBA IEGT. Copyright © 2004 John Wiley & Sons, Ltd.
Atmospheric transmissivity: distribution and empirical estimation around the central Andes
Authors: Baigorria Guillermo A. , Villegas Esequiel B. , Trebejo Irene , Carlos Jose F. , Quiroz Roberto 
Published: June 2004

AbstractThis study of the distribution in space and time of atmospheric transmissivity τ takes into account the fact that, in complex terrain, many factors affect this variable; thus, it is not possible to use the generalizations that can be applied under more homogeneous conditions. Climatic controls, topography and even sea currents have important effects on clouds and aerosols affecting τ, simultaneously leading to differences in the distribution of incident solar radiation. Different models exist to estimate incoming solar radiation as a function of relative sunshine hours (observed sunshine hours/theoretical sunshine hours, n/N) or differences between maximum and minimum temperatures Δ T. We calibrated, validated and evaluated four of these empirical relations based on data from 15 weather stations in Peru. Models were calibrated using 66% of the daily historical record available for each weather station; the rest of the information was used for validation and comparison. The Ångström–Prescott model was used to estimate incoming solar radiation based on n/N, and gave the best performance of all the models tested. The other models (Bristow–Campbell, Hargreaves, and Garcia) estimated incoming solar radiation based on Δ T. Of all the models in this group, the Bristow–Campbell model performed best; it is also valuable because of the physical explanation involved. The empirical coefficients of all the models evaluated are presented here. Two empirical equations are proposed with which to estimate values of the coefficients bB and cB in the Bristow–Campbell model, as a function of Δ T and latitude, allowing the model to be applied to other study areas. Copyright © 2004 Royal Meteorological Society
Changes in Australian pan evaporation from 1970 to 2002
Authors: Roderick Michael L. , Farquhar Graham D. 
Published: June 2004

AbstractContrary to expectations, measurements of pan evaporation show decreases in many parts of the Northern Hemisphere over the last 50 years. When combined with rainfall measurements, these data show that much of the Northern Hemisphere's terrestrial surface has become less arid over the last 50 years. However, whether the decrease in pan evaporation is a phenomenon limited to the Northern Hemisphere has until now been unknown because there have been no reports from the Southern Hemisphere. Here, we report a decrease in pan evaporation rate over the last 30 years across Australia of the same magnitude as the Northern Hemisphere trends (approximately −4 mm a−2). The results show that the terrestrial surface in Australia has, on average, become less arid over the recent past, just like much of the Northern Hemisphere. Copyright © 2004 Royal Meteorological Society.
Optimization of micellar liquid chromatographic separation of polycyclic aromatic hydrocarbons with the addition of second organic additive
Authors: Mao Chunfeng , McGill Kelly E. , Tucker Sheryl A. 
Published: June 2004

AbstractThe micellar liquid chromatographic (MLC) separations of polycyclic aromatic hydrocarbons (PAHs) were optimized for three micellar systems, cetyltrimethylammonium chloride (CTAC), dodecyltrimethylammonium chloride (DTAC), and sodium dodecylsulfate (SDS), with 1‐pentanol as the only organic additive. A difference in the separation was observed between CTAC and SDS/DTAC. Under each optimized separation conditions, CTAC‐modified mobile phase provides the least desirable separation, which is attributed to its longer carbon tail (C16 vs. C12). In addition to 1‐pentanol, the main organic additive, a second organic additive (3% 1‐propanol) in the micelle‐modified mobile phase was found to enhance the resolution of PAH chromatographic peaks. However, the extent of the enhancement varies for the different micellar systems, with the greatest resolution improvement seen for CTAC, and little effect for shorter‐tail SDS and DTAC. This study shows the potential use of second organic additive (1‐propanol), to the main nonpolar additive (1‐pentanol), in facilitating the MLC separation of larger nonpolar compounds.
Analyzing liver transplantation for fulminant hepatic failure at UCLA: A retrospective look at 18 years’ experience
Authors: Lee William M. , Polson Julie 
Published: June 2004

Objective
To analyze outcomes after liver transplantation (LT) in patients with fulminant hepatic failure (FHF) with emphasis on pretransplant variables that can potentially help predict posttransplant outcome.

Summary background data
FHF is a formidable clinical problem associated with a high mortality rate. While LT is the treatment of choice for irreversible FHF, few investigations have examined pretransplant variables that can potentially predict outcome after LT.

Methods
A retrospective review was undertaken of all patients undergoing LT for FHF at a single transplant center. The median follow-up was 41 months. Thirty-five variables were analyzed by univariate and multivariate analysis to determine their impact on patient and graft survival.

Results
Two hundred four patients (60% female, median age 20.2 years) required urgent LT for FHF. Before LT, the majority of patients were comatose (76%), on hemodialysis (16%), and bound for intensive care. The 1- and 5-year survival rates were 73% and 67% (patient) and 63% and 57% (graft). The primary cause of patient death was sepsis, and the primary cause of graft failure was primary graft nonfunction. Univariate analysis of pre-LT variables revealed that 19 variables predicted survival. From these results, multivariate analysis determined that the serum creatinine was the single most important prognosticator of patient survival.

Conclusions
This study, representing one of the largest published series on LT for FHF, demonstrates a long-term survival of nearly 70% and develops a clinically applicable and readily measurable set of pretransplant factors that determine posttransplant outcome. (Ann Surg 2003;237:666-676.)