bluuebunny/crossref_metadata_2025 huggingface dataset:
Metabolism of Deuterated erythro‐Dihydroxy Fatty Acids in Saccharomyces cerevisiae: Enantioselective Formation and Characterization of Hydroxylactones
Authors: Garbe Leif‐A. , Morgenthal Katja , Kuscher Katrin , Tressl Roland
Published: July 2008

Epoxides of fatty acids are hydrolyzed by epoxide hydrolases (EHs) into dihydroxy fatty acids which are of particular interest in the mammalian leukotriene pathway. In the present report, the analysis of the configuration of dihydroxy fatty acids via their respective hydroxylactones is described. In addition, the biotransformation of (±)‐erythro‐7,8‐ and ‐3,4‐dihydroxy fatty acids in the yeast Saccharomyces cerevisiae was characterized by GC/EI‐MS analysis. Biotransformation of chemically synthesized (±)‐erythro‐7,8‐dihydroxy(7,8‐2H2)tetradecanoic acid ((±)‐erythro‐1) in the yeast S. cerevisiae resulted in the formation of 5,6‐dihydroxy(5,6‐2H2)dodecanoic acid (6), which was lactonized into (5S,6R)‐6‐hydroxy(5,6‐2H2)dodecano‐5‐lactone ((5S,6R)‐4) with 86% ee and into erythro‐5‐hydroxy(5,6‐2H2)dodecano‐6‐lactone (erythro‐8). Additionally, the α‐ketols 7‐hydroxy‐8‐oxo(7‐2H1)tetradecanoic acid (9a) and 8‐hydroxy‐7‐oxo(8‐2H1)tetradecanoic acid (9b) were detected as intermediates. Further metabolism of 6 led to 3,4‐dihydroxy(3,4‐2H2)decanoic acid (2) which was lactonized into 3‐hydroxy(3,4‐2H2)decano‐4‐lactone (5) with (3R,4S)‐5=88% ee. Chemical synthesis and incubation of (±)‐erythro‐3,4‐dihydroxy(3,4‐2H2)decanoic acid ((±)‐erythro‐2) in yeast led to (3S,4R)‐5 with 10% ee. No decano‐4‐lactone was formed from the precursors 1 or 2 by yeast. The enantiomers (3S,4R)‐ and (3R,4S)‐3,4‐dihydroxy(3‐2H1)nonanoic acid ((3S,4R)‐ and (3R,4S)‐3) were chemically synthesized and comparably degraded by yeast without formation of nonano‐4‐lactone. The major products of the transformation of (3S,4R)‐ and (3R,4S)‐3 were (3S,4R)‐ and (3R,4S)‐3‐hydroxy(3‐2H1)nonano‐4‐lactones ((3S,4R)‐ and (3R,4S)‐7), respectively. The enantiomers of the hydroxylactones 4, 5, and 7 were chemically synthesized and their GC‐elution sequence on Lipodex® E chiral phase was determined.
Shuffled Complex Evolution model calibrating algorithm: enhancing its robustness and efficiency
Authors: Muttil Nitin , Jayawardena A. W.
Published: July 2008

Shuffled Complex Evolution—University of Arizona (SCE‐UA) has been used extensively and proved to be a robust and efficient global optimization method for the calibration of conceptual models. In this paper, two enhancements to the SCE‐UA algorithm are proposed, one to improve its exploration and another to improve its exploitation of the search space. A strategically located initial population is used to improve the exploration capability and a modification to the downhill simplex search method enhances its exploitation capability. This enhanced version of SCE‐UA is tested, first on a suite of test functions and then on a conceptual rainfall‐runoff model using synthetically generated runoff values. It is observed that the strategically located initial population drastically reduces the number of failures and the modified simplex search also leads to a significant reduction in the number of function evaluations to reach the global optimum, when compared with the original SCE‐UA. Thus, the two enhancements significantly improve the robustness and efficiency of the SCE‐UA model calibrating algorithm. Copyright © 2008 John Wiley & Sons, Ltd.
Bid–ask spread and order size in the foreign exchange market: an empirical investigation
Authors: Ding Liang
Published: July 2008

This article empirically examines the relationship between order sizes and spreads in the foreign exchange (FX) market based on a FX dealer's quotes. It is found that spreads are independent of order sizes in the inter‐dealer market, but they are negatively correlated in the customer market. Copyright © 2008 John Wiley & Sons, Ltd.
Effect of rounded‐edge entrance on discharge coefficient of side weir in rectangular channels
Authors: Honar Tooraj , Keshavarzi Alireza
Published: July 2008

Side weirs are flow diversion devices that are widely used in irrigation and drainage networks and urban sewage systems. They are usually built with a squared‐edge entrance. The present study focuses on the effect of rounded‐edge entrance shape on the discharge coefficient of a side weir under subcritical flow condition in rectangular channels. In this study, 90 laboratory tests were conducted and the results were analyzed to find the influence of non‐dimensional hydraulic parameters on the discharge coefficient. From the results, it was found that under subcritical flow condition the side weir with rounded‐edge entrance discharges 10% more flow rate than the squared edge entrance. As a result, for equal flow rate, the rounded‐edge entrance side weir with small dimensions can be designed for use in practical applications. Copyright © 2008 John Wiley & Sons, Ltd.
Carcinogenic chromium(VI)‐induced protein oxidation and lipid peroxidation: implications in DNA–protein crosslinking
Authors: Mattagajasingh Subhendra N. , Misra Bhaba R. , Misra Hara P.
Published: July 2008

Hexavalent chromium [Cr(VI)] compounds are Group‐I human carcinogens. Cr(VI)‐induced DNA–protein crosslinks (DPCs) have been implicated in the mutagenic and carcinogenic effects of Cr(VI). Although multiple mechanisms have been suggested for Cr(VI)‐induced DNA–protein crosslinking, the mechanism of formation of DNA–protein crosslinks is not well understood. In this study, we explored the hypothesis that Cr(VI)‐induced DPCs could be formed via generation of protein carbonyls and malonaldehyde (MDA) through protein oxidation and lipid peroxidation, respectively. Treatment of human leukemic T‐lymphocyte MOLT4 cells with potassium chromate induced the formation of protein carbonyls and DPCs within 2 h, but increased the level of MDA only after 4 h, in a dose‐dependent manner. Chromate treatment of MOLT4 cell homogenates also resulted in increased formation of MDA and protein carbonyls in a dose‐dependent manner. EPR spectrometry in combination with spin trapping techniques revealed that reaction of Cr(VI) with biological reductants such as NADPH, glutathione reductase or H2O2 generates Cr(V) and •OH radicals. Pretreatment of cells with antioxidants such as α‐tocopherol or Tiron inhibited chromate‐induced increase in formation of protein carbonyls, MDA and DPCs, but pretreatment of cells with riboflavin or 3‐aminotriazole, a catalase inhibitor, had the opposite effect. Our results, for the first time, demonstrate that Cr(VI) exposure increases the cellular level of protein carbonyls and that Cr(VI)‐induced DPCs may be formed, at least in part, via generation of protein carbonyls. Copyright © 2008 John Wiley & Sons, Ltd.
In vivo evaluation of biodegradable magnesium alloy bone implant in the first 6 months implantation
Authors: Zhang Erlin , Xu Liping , Yu Guoning , Pan Feng , Yang Ke
Published: July 2008

In vivo degradation of magnesium alloy implant, the bone response to the magnesium, and the effect of the degradation of magnesium on the blood composition and organs were investigated by using light microscopy and scanning electronic microscopy with energy dispersive spectrum. Magnesium alloy showed different degradation rates in the marrow channel and the cortical bone. More degradation of magnesium implant was observed in the marrow channel than in the cortical bone. New bone tissue formed around the magnesium implants after 6 weeks implantation but no fibrous capsule was found. There existed two distinct layers separating the new bone tissue from the magnesium implant. On the magnesium implant side, crystalline magnesium calcium phosphate formed on the surface of the implant due to the reaction between the implant and blood or body fluid. On the new bone tissue side was a 10–30‐μm membrane comprising two distinct layers with many fibroblasts in the layer close to the new bone tissue. The new bone was in tight contact with the implant through the membrane and phosphate layer due to the good osteoconductivity of the phosphate layer. After 10 and 26 weeks postimplantation, more new bone tissues as well as the membrane were found around the implant. However, no apparent increase in the thickness of the membrane was observed with the increasing of the implantation duration. Blood examination has shown that the degradation of the magnesium implant caused little change to blood composition but no disorder to liver or kidneys. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res, 2009
Surface AFM microscopy of unworn and worn samples of silicone hydrogel contact lenses
Authors: González‐Méijome J. M. , López‐Alemany A. , Almeida J. B. , Parafita M. A.
Published: July 2008

Purpose.

To evaluate the qualitative and quantitative topographic changes in the surface of worn contact lenses (CLs) of different materials using atomic force microscopy (AFM).

Methods.

The topography of five different CL materials was evaluated with AFM over a surface of 25 μm2 according to previously published experimental setup. Average roughness (Ra) and root mean square (Rms) values were obtained for unworn and worn samples.

Results.

The Ra value increased for balafilcon A (11.62–13.68 nm for unworn and worn samples, respectively), lotrafilcon A (3.67–15.01 nm for unworn and worn samples, respectively), lotrafilcon B (4.08–8.42 nm for unworn and worn samples, respectively), galyfilcon A (2.81–14.6 nm for unworn and worn samples, respectively), and comfilcon A (2.87–4.63 nm for unworn and worn samples, respectively). Differences were statistically significant for all lenses except Rms and Ra for comfilcon A, and Ra parameter for balafilcon A (p > 0.05). The least relative increase was observed for some balafilcon A samples and for some of these samples the roughness decreased after the lenses had been worn.

Conclusion.

The changes in surface roughness between unworn and worn lenses are different for different silicone‐hydrogel materials. Overall all CLs increased the degree of surface roughness after being worn, even for very short periods of time. However, for samples of balafilcon A, roughness increases at a lower extent or even can decrease as compared to unworn samples of the same material due to filling of the macropores. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Real time noninvasive monitoring of contaminating bacteria in a soft tissue implant infection model
Authors: Engelsman Anton F. , van der Mei Henny C. , Francis Kevin P. , Busscher Henk J. , Ploeg Rutger J. , van Dam Gooitzen M.
Published: July 2008

Infection is the main cause of biomaterials‐related failure. A simple technique to test in‐vivo new antimicrobial and/or nonadhesive implant coatings is unavailable. Current invitro methods for studying bacterial adhesion and growth on biomaterial surfaces lack the influence of the host immune system. Most in vivo methods to study biomaterials‐related infections routinely involve implant‐removal, preventing comprehensive longitudinal monitoring. In vivo imaging circumvents these drawbacks and is based on the use of noninvasive optical imaging of bioluminescent bacteria. Staphylococcus aureus Xen29 is genetically modified to be stably bioluminescent, by the introduction of a modified full lux operon onto its chromosome. Surgical meshes with adhering S. aureus Xen29 were implanted in mice and bacterial growth and spread into the surrounding tissue was monitored longitudinally from bioluminescence with a highly sensitive CCD camera. Distinct spatiotemporal bioluminescence patterns, extending beyond the mesh area into surrounding tissues were observed. After 10 days, the number of living organisms isolated from explanted meshes was found to correlate with bioluminescence prior to sacrifice of the animals. Therefore, it is concluded that in vivo imaging using bioluminescent bacteria is ideally suited to study antimicrobial coatings taking into account the host immune system. In addition, longitudinal monitoring of infection in one animal will significantly reduce the number of experiments and animals. © 2008 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2009
Lessons learned from the Oklahoma Thrombotic Thrombocytopenic Purpura‐Hemolytic Uremic Syndrome Registry
Authors: George James N. , Terrell Deirdra R. , Swisher Karen K. , Vesely Sara K.
Published: July 2008

The Oklahoma TTP‐HUS Registry provides a complete community perspective of thrombotic thrombocytopenic purpura (TTP). This is possible because plasma exchange is the essential treatment for TTP and the Oklahoma Blood Institute provides all plasma exchange procedures for a region encompassing most of the State, including 58 of Oklahoma's 77 counties. The Registry is an inception cohort of consecutive patients for whom plasma exchange treatment was requested for a diagnosis of either TTP or hemolytic uremic syndrome (HUS). All 382 patients identified from January 1, 1989 to December 31, 2007 have consented to be enrolled. Complete follow‐up is available for 380 of 382 patients. Patients are described both by clinical categories, related to their associated conditions and clinically apparent etiologies, and by the presence of severe ADAMTS13 deficiency. ADAMTS13 activity has been measured on 235 (93%) of 254 patients since 1995. Registry data have provided new perspectives on the definition and diagnoses of these syndromes as well as their outcomes. Long‐term follow‐up has documented that relapse is common among patients with ADAMTS13 deficiency but rarely occurs in patients without ADAMTS13 deficiency. Long‐term follow‐up has also documented persistent abnormalities of health‐related quality‐of‐life and cognitive function. In addition to providing new perspectives on the natural history of these syndromes, The Oklahoma TTP‐HUS Registry provides a support group for our patients, information about evaluation and management for community physicians, and a resource for research and educational programs. J. Clin. Apheresis, 2008. © 2008 Wiley‐Liss, Inc.
Identifying functional neighborhoods within the cell nucleus: Proximity analysis of early S‐phase replicating chromatin domains to sites of transcription, RNA polymerase II, HP1γ, matrin 3 and SAF‐A
Authors: Malyavantham Kishore S. , Bhattacharya Sambit , Barbeitos Marcos , Mukherjee Lopamudra , Xu Jinhui , Fackelmayer Frank O. , Berezney Ronald
Published: July 2008

Higher order chromatin organization in concert with epigenetic regulation is a key process that determines gene expression at the global level. The organization of dynamic chromatin domains and their associated protein factors is intertwined with nuclear function to create higher levels of functional zones within the cell nucleus. As a step towards elucidating the organization and dynamics of these functional zones, we have investigated the spatial proximities among a constellation of functionally related sites that are found within euchromatic regions of the cell nucleus including: HP1γ, nascent transcript sites (TS), active DNA replicating sites in early S‐phase (PCNA) and RNA polymerase II sites. We report close associations among these different sites with proximity values specific for each combination. Analysis of matrin 3 and SAF‐A sites demonstrates that these nuclear matrix proteins are highly proximal with the functionally related sites as well as to each other and display closely aligned and overlapping regions following application of the minimal spanning tree (MST) algorithm to visualize higher order network‐like patterns. Our findings suggest that multiple factors within the nuclear microenvironment collectively form higher order combinatorial arrays of function. We propose a model for the organization of these functional neighborhoods which takes into account the proximity values of the individual sites and their spatial organization within the nuclear architecture. J. Cell. Biochem. 105: 391–403, 2008. © 2008 Wiley‐Liss, Inc.
Resolvable packings of Kv with K2 × Kc's
Authors: Li Yang , Yin Jianxing
Published: July 2008

The study of resolvable packings of Kv with Kr × Kc's is motivated by the use of DNA library screening. We call such a packing a (v, Kr × Kc, 1)‐RP. As usual, a (v, Kr × Kc, 1)‐RP with the largest possible number of parallel classes (or, equivalently, the largest possible number of blocks) is called optimal. The resolvability implies v ≡ 0 (mod rc). Let ρ be the number of parallel classes of a (v, Kr × Kc, 1)‐RP. Then we have ρ ≤ ⌊(v‐1)/(r + c − 2)⌋. In this article, we present a number of constructive methods to obtain optimal (v, K2 × Kc, 1)‐RPs meeting the aforementioned bound and establish some existence results. In particular, we show that an optimal (v, K2 × K3, 1)‐RP meeting the bound exists if and only if v ≡ 0 (mod 6). © 2008 Wiley Periodicals, Inc. J Combin Designs 17: 177–189, 2009
Finding blunders in thyroid testing: experience in newborns
Authors: Zilka Laurel J. , Lott John A. , Baker Lula C. , Linard Sharon M.
Published: July 2008

We evaluated thyroxin (T4) and thyroid‐stimulating hormone (TSH) data along with clinical information from 600,000 newborns. We looked for certain combinations of tests and clinical data that were questionable and possibly mistaken. Our approach suggests that certain combinations of test results, especially the presence of missing results deserved further evaluation for possible blunders. We found that missing tests were frequently the result of oversight. The laboratory used the well‐known standard blood‐spot‐on‐filter paper methods for TSH and T4. For quantitation of TSH and T4, we used the time‐resolved fluoroimmunoassay available from Perkin Elmer. We found 56 babies with confirmed primary congenital hypothyroidism (PCH) in a total of 600,000 patients. We also found 18 sets of results in the same 600,000 babies that gave inconsistent findings, had missing values, and (or) possible misinterpretations of the clinical and (or) laboratory data. What is an acceptable mistake rate? All mistakes are unacceptable, but there is likely some irreducible mistake rate, and efforts to reduce the mistake or blunder rate still further may not be cost‐effective. What can be done is to study the mistake rate per 600,000 babies from year to year; the mistake rate should be decreasing or not changing. This assumes a stable cohort of babies; an assumption that may be acceptable. We applied a form of pattern recognition to identify cases of possible blunders and missing values in either the laboratory or clinical data. What is clear is that we apparently identified some blunders. The 18 mistakes per 600,000 babies may be “very low” and acceptable. We recommend that seeking ever decreasing mistakes is the way to go, and the level of monitoring the data should be very intense given the serious consequences of mis‐diagnosed thyroid disorders. J. Clin. Lab. Anal. 22:254–256, 2008. © 2008 Wiley‐Liss, Inc.
An abductive perspective on clinical reasoning and case formulation
Authors: Vertue Frances M. , Haig Brian D.
Published: July 2008

Clinical reasoning has traditionally been understood in terms of either hypothetico‐deductive or Bayesian methods. However, clinical psychology requires an organizing framework that goes beyond the limits of these methods and characterizes the full range of reasoning processes involved in the description, understanding, and formulation of the difficulties presented by clients. In this article, the authors present a framework for clinical reasoning and case formulation that is largely based on a broad abductive theory of scientific method (Haig, 2005b). The abductive theory articulates and combines the processes of phenomena detection and theory construction. Both of these processes are applied to clinical reasoning and case formulation, and a running case example is provided to illustrate the application. © 2008 Wiley Periodicals, Inc. J Clin Psychol 64:1–24, 2008.
Determination of the adequate minimum model complexity required in anaerobic bioprocesses using experimental data
Authors: Rodríguez Jorge , Roca Enrique , Lema Juan M , Bernard Olivier
Published: July 2008

BACKGROUND: Modelling of anaerobic bioprocesses requires adequate conciliation between model accuracy and complexity. Anaerobic digestion is a highly complex biocatalysed process in which organic (waste) materials are converted into biogas. Complex mathematical models of the process can be difficult to manage, while too simplistic models may be insufficient for specific applications.

RESULTS: A technique based on principal component analysis (PCA) is presented to assess the most adequate complexity in anaerobic bioprocess models using preliminary data. The technique is applied to experimental data from a continuously operated pilot‐scale anaerobic digestion process treating diluted wine and to process simulation data generated by a highly complex model (ADM1). The results obtained suggest that models incorporating only four reactions can describe most of the experimental data variability. Similarly, a simplification of the highly complex modified ADM1 used to a four‐reaction model could attain equivalent simulation accuracy. A set of possible four‐reaction networks was evaluated using the PCA information and a best candidate network of reactions is obtained.

CONCLUSION: The developed PCA‐based tool allows for the assessment of the adequate complexity in mathematical models of anaerobic digestion of ethanol, a process that appears describable with a high level of accuracy by considering only four biological reactions. Copyright © 2008 Society of Chemical Industry
Saponaria officinalis karyology and karyotype by means of image analyzer and atomic force microscopy
Authors: Di Bucchianico S. , Venora G. , Lucretti S. , Limongi T. , Palladino L. , Poma A.
Published: July 2008

The aim of this work was to offer a contribution to the characterization of taxonomic entity of Saponaria officinalis (2n = 28; an herbaceous perennial species; saporin, a type 1 Ribosome Inactivating Protein, is present in leaves and seeds) by a cytogenetic and karyomorphological approach. We investigated the karyotype's morphometry correlated with Stebbin's symmetric index; the same information has been used for computing the indices resemblance between chromosomes (REC), symmetric indices (SYI), and total form (TF%) which allow the comparison between species and evaluation of karyological evolution. Fluorescence intensities of the stained nuclei were measured by a flow cytometer and, for the first time, values for nuclear DNA content were estimated by comparing nuclei fluorescence intensities of the test population with those of appropriate internal DNA standards. Our study is also aimed to introduce chromosomal volumes, which were determined by atomic force microscopy (AFM), as novel karyomorphological parameter which could allow for chromosome discrimination especially when tiny ones are present. Microsc. Res. Tech., 2008. © 2008 Wiley‐Liss, Inc.
Care and parentage in a skin‐feeding caecilian amphibian
Authors: Kupfer Alexander , Wilkinson Mark , Gower David J. , Müller Hendrik , Jehle Robert
Published: July 2008

An exceptional form of parental care has recently been discovered in a poorly known caecilian amphibian. Mothers of the Taita Hills (Kenya) endemic Boulengerula taitanus provide their own skin as a food source for their offspring. Field data suggest that nursing is costly. Females found attending young had a lower body condition and fat body volume than nonbrooding and egg‐incubating females, and the female condition decreased substantially during parental care. Most mothers and their eggs or offspring were found in close proximity to other nesting females, in high‐density nest sites that enhance the potential for social interactions and highlighting the possibility of communal breeding. Parentage was investigated using Amplified Fragment Length Polymorphism (AFLP) genetic markers in 29 offspring from six litters guarded by putative mothers. Our data provide the first evidence of multiple paternity in a caecilian, implying that two fathers sired one litter. Some young from two litters had genotypes not matching the guarding female suggesting that not all offspring are cared for by their biological mothers. This study provides evidence for alloparenting in an amphibian with cost‐intensive parental care. J. Exp. Zool. 309A:460–467, 2008. © 2008 Wiley‐Liss, Inc.
Unilateral ovariectomy increases egg size and reduces follicular atresia in the semelparous coho salmon, Oncorhynchus kisutch
Authors: Luckenbach John Adam , Kusakabe Makoto , Swanson Penny , Young Graham
Published: July 2008

Unilateral ovariectomy (ULO, removal of one ovary) is a powerful technique for studying aspects of reproductive physiology, including follicular recruitment and growth. To examine effects of ULO for the first time in a semelparous species, coho salmon (Oncorhynchus kisutch) were unilaterally ovariectomized during mid‐vitellogenesis approximately 3 months before spawning. At termination of the study (79 days post‐surgery), single ovaries of ULO fish were gravimetrically equivalent to paired ovaries of sham surgery, control fish. There was no evidence of recruitment of new vitellogenic follicles. Instead, the dramatic increase in ovary mass was attributable to hypertrophy of existing vitellogenic follicles (33% increase in volume) and increased fecundity achieved through a greater than two‐fold reduction in follicular atresia. The composition of whole ovaries on a dry weight basis from ULO fish was greater in protein, but lower in lipid than that of control fish. Expressing the data on a per follicle basis, however, showed that follicles of ULO fish contained more protein, ash, water, and lipid. The results indicate that ULO of coho salmon induces compensatory hypertrophy of existing vitellogenic follicles, while maximizing fecundity through reduction of atresia. Thus, 3 months before spawning, coho salmon exhibit the ability to adjust final egg size and number when faced with significant depletion of ovarian follicles. This in vivo system provides a platform for further study of physiological mechanisms regulating follicular growth and atresia, and the trade‐off between egg size and egg number. J. Exp. Zool. 309A:468–476, 2008. © 2008 Wiley‐Liss, Inc.
The tissue plasminogen activator gene promoter: a novel tool for radiogenic gene therapy of the prostate?
Authors: Marignol L. , Robson T. , McCarthy H. O. , Worthington J. , Murray M. M. , Hollywood D. , Lawler M. , Hirst D. G.
Published: July 2008

Background

Radiation therapy is a treatment modality routinely used in cancer management so it is not unexpected that radiation‐inducible promoters have emerged as an attractive tool for controlled gene therapy. The human tissue plasminogen activator gene promoter (t‐PA) has been proposed as a candidate for radiogenic gene therapy, but has not been exploited to date. The purpose of this study was to evaluate the potential of this promoter to drive the expression of a reporter gene, the green fluorescent protein (GFP), in response to radiation exposure.

Methods

To investigate whether the promoter could be used for prostate cancer gene therapy, we initially transfected normal and malignant prostate cells. We then transfected HMEC‐1 endothelial cells and ex vivo rat tail artery and monitored GFP levels using Western blotting following the delivery of single doses of ionizing radiation (2, 4, 6 Gy) to test whether the promoter could be used for vascular targeted gene therapy.

Results

The t‐PA promoter induced GFP expression up to 6‐fold in all cell types tested in response to radiation doses within the clinical range.

Conclusions

These results suggest that the t‐PA promoter may be incorporated into gene therapy strategies driving therapeutic transgenes in conjunction with radiation therapy. Copyright © 2008 John Wiley & Sons, Ltd.
Significant antitumor activity of oncolytic adenovirus expressing human interferon‐β for hepatocellular carcinoma
Authors: He Ling Feng , Gu Jin Fa , Tang Wen Hao , Fan Jun Kai , Wei Na , Zou Wei Guo , Zhang Yan Hong , Zhao Li Li , Liu Xin Yuan
Published: July 2008

Background

Human interferon‐β (IFN‐β) has been widely used in gene therapy for its antitumor activity but its therapeutic effect is limited. The conditionally replicative adenovirus ONYX‐015 (a E1B‐55‐kDa‐deleted adenovirus) targets well to tumor cells, but is not potent enough to cause significant tumor regression. To solve these problems, a tumor‐selective replicating adenovirus expressing IFN‐β was constructed in this study.

Methods

The oncolytic adenoviruses were generated by homologous recombination in packaging cells. The expression of the IFN‐β protein was detected by enzyme‐linked immunosorbent assay (ELISA). The antitumor efficacy of ZD55‐IFN‐β was evaluated in cell lines and human hepatocellular carcinoma xenografts in nude mice.

Results

ZD55‐IFN‐β can express much more IFN‐β than Ad‐IFN‐β because of the replication of the ZD55 vector. Our data showed that ZD55‐IFN‐β could exert a strong cytopathic effect on tumor cells (about 100‐fold higher than Ad‐IFN‐β or ONYX‐015). Moreover, no obvious cytotoxic or apoptotic effects were detected in normal cells infected with ZD55‐IFN‐β.

Conclusions

The antitumor efficacy of IFN‐β could be significantly improved due to the increased gene expression level from the tumor‐selective replicating vector. The oncolytic adenovirus expressing IFN‐β may provide a novel approach for cancer gene therapy. Copyright © 2008 John Wiley & Sons, Ltd.
Cycle spaces in topological spaces
Authors: Vella Antoine , Richter R. Bruce
Published: July 2008

We develop a general model of edge spaces in order to generalize, unify, and simplify previous work on cycle spaces of infinite graphs. We give simple topological criteria to show that the fundamental cycles of a (generalization of a) spanning tree generate the cycle space in a connected, compact, weakly Hausdorff edge space. Furthermore, in such a space, the orthogonal complement of the bond space is the cycle space. This work unifies the two different notions of cycle space as introduced by Diestel and Kühn [Combinatorica 24 (2004), 68–89 and Eur J Combin 25 (2004), 835–862] and by Bonnington and Richter [J Graph Theory 44 (2003), 132–147]. © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 115–144, 2008
The bond and cycle spaces of an infinite graph
Authors: Casteels Karel , Richter R. Bruce
Published: July 2008

Bonnington and Richter defined the cycle space of an infinite graph to consist of the sets of edges of subgraphs having even degree at every vertex. Diestel and Kühn introduced a different cycle space of infinite graphs based on allowing infinite circuits. A more general point of view was taken by Vella and Richter, thereby unifying these cycle spaces. In particular, different compactifications of locally finite graphs yield different topological spaces that have different cycle spaces. In this work, the Vella‐Richter approach is pursued by considering cycle spaces over all fields, not just ℤ2. In order to understand “orthogonality” relations, it is helpful to consider two different cycle spaces and three different bond spaces. We give an analog of the “edge tripartition theorem” of Rosenstiehl and Read and show that the cycle spaces of different compactifications of a locally finite graph are related. © 2008 Wiley Periodicals, Inc. J Graph Theory 59: 162–176, 2008
Theoretical and experimental study of tropylium formation from substituted benzylpyridinium species
Authors: Zins Emilie‐Laure , Pepe Claude , Rondeau David , Rochut Sophie , Galland Nicolas , Tabet Jean‐Claude
Published: July 2008

Fragmentation pathways of unsubstituted and substituted benzylpyridinium compounds were investigated using mass‐analysed kinetic energy (MIKE) technique in combination with high level of quantum chemical calculations in the gas phase. Fast atom bombardment (FAB) source was used for ionisation of the studied compounds. The formation of both benzylium and tropylium species were investigated. Hybrid Hartree‐Fock/Density Functional Theory calculations have been performed to assess the geometries and the energies of the transition states and intermediates. For each cases, different reaction pathways were investigated, and particularly in the case of the formation of tropylium species, the formation of the seven‐membered ring before or after the loss of pyridine were studied. The effect of para‐methyl and para‐methoxy substituents on the activation energy of the rearrangement process to form thermodynamically stable tropylium compounds has been studied. Theoretical calculations showed competition between direct bond cleavage and rearrangement reactions to form benzylium and tropylium compounds, respectively. Experimental results also suggested that the rearrangement process takes place to yield stable tropylium under “soft ionisation techniques”, such as FAB. Copyright © 2008 John Wiley & Sons, Ltd.
Activation of adenosine A1receptor–induced neural stem cell proliferation via MEK/ERK and Akt signaling pathways
Authors: Migita Hideyuki , Kominami Katsuya , Higashida Mami , Maruyama Rumi , Tuchida Nobuko , McDonald Fiona , Shimada Fumiki , Sakurada Kazuhiro
Published: July 2008

Adenosine, a modulator of neuronal function in the mammalian central nervous system, exerts a neuroprotective effect via the adenosine A1receptor; however, its effect on neural stem cells (NSCs) remains unclear. Because adenosine is released in response to pathological conditions and NSCs play a key role in neuroregeneration, we tested the hypothesis that adenosine is capable of stimulating NSC proliferation. We demonstrated that NSCs dominantly express adenosine A1and A2Breceptors. Adenosine and the adenosine A1receptor agonist cyclopentyladenosine (CPA) increased proliferation of NSCs, and this CPA‐induced cell proliferation was attenuated by the A1antagonist 8‐cyclopentyl‐1,3‐dipropylxanthine (DPCPA). CPA also induced phosphorylation of extracellular signal–regulated kinase (ERK), mitogen‐activated protein kinase/ERK kinase (MEK), and Akt, and their phosphorylation was inhibited by DPCPA. In addition, CPA‐induced cell proliferation was inhibited by MEK and Akt inhibitors. These results suggest that activation of adenosine A1receptor–stimulated proliferation of NSCs occurs via MEK/ERK and Akt signaling pathways. © 2008 Wiley‐Liss, Inc.
17β‐Estradiol attenuates hyperoxia‐induced apoptosis in mouse C8‐D1A cell line
Authors: Huppmann Stephanie , Römer Susanne , Altmann Rodica , Obladen Michael , Berns Monika
Published: July 2008

In premature infants, oxygen free radicals generated following neonatal resuscitation are associated with subsequent diseases such as retinopathy of prematurity and bronchopulmonary dysplasia. Recent studies in brain tissue samples have shown that nonphysiologic oxygen levels play a key role in induction of apoptosis in the developing brain. Estrogen is a well‐established agent in neuroprotection and, therefore, is thought to be neuroprotective even in the premature brain. Astrocytes appear to have a critical role in protection and survival of neurons in the brain. As one of the glial cell types, they have a great potential for possible involvement in the mediation of estrogen neuroprotective effects. The aim of our study was to analyze whether astrocytes in cell cultures are damaged by hyperoxia and whether 17β‐estradiol (E2) can protect them against apoptosis. Additionally, we investigated the mechanism of the protection by E2, hypothesizing that it is mediated through extracellular signal‐regulated kinase (ERK1/2). Cells underwent eightfold more apoptosis when cultivated in hyperoxia compared with normoxia. Addition of E2 reduced apoptosis in hyperoxia by more than 50%. Levels of ERK1/2 and phosphorylated ERK1/2 were increased after hyperoxia compared with normoxia. Preincubation with E2 prior to exposure to hyperoxia resulted in decreased levels of ERK1/2 and pERK1/2. Hyperoxia induces apoptosis in C8‐D1A cells, and E2 seems to be a protecting factor for astrocytes in hyperoxia. This effect is not mediated through up‐regulation of pERK1/2. © 2008 Wiley‐Liss, Inc.
Liquid‐phase microextraction for rapid AP‐MALDI and quantitation of nortriptyline in biological matrices
Authors: Wu Hui‐Fen , Ku Hsin‐Yi , Yen Jyh‐Hao
Published: July 2008

A liquid‐phase microextraction (LPME) method using a micropipette with disposable tips was demonstrated for coupling to atmospheric pressure MALDI‐MS (AP‐MALDI/MS) as a concentrating probe for rapid analysis and quantitative determination of nortriptyline drug from biological matrices including human urine and human plasma. This technique was named as micropipette extraction (MPE). The best optimized parameters of MPE coupled to AP‐MALDI/MS experiments were extraction solvent, toluene; extraction time, 5 min; sample agitation rate, 480 rpm; sample pH, 7; salt concentration, 30%; hole size of micropipette tips, 0.61 mm (id); and matrix concentration, 1000 ppm using α‐cyano‐4‐hydroxycinnamic acid (CHCA) as a matrix. Three detection modes of AP‐MALDI/MS analysis including full scan, selective ion monitor (SIM), and selective reaction monitor (SRM) of MS/MS were also compared for the MPE performance. The results clearly demonstrated that the MS/MS method provides a wider linear range and lower LODs but poor RSDs than the full scan and SIM methods. The LOD values for the MPE under SIM and MS/MS modes in water, urine, and plasma were 6.26, 47.5, and 94.9 nM, respectively. The enrichment factors (EFs) of this current approach were 36.5–43.0 fold in water. In addition, compared to single drop microextraction (SDME) and LPME using a dual gauge microsyringe with a hollow fiber (LPME‐HF) technique, the LODs acquired by the MPE method under MS/MS modes were comparable to those of LPME‐HF and SDME but it is more convenient than both methods. The advantages of this novel method are simple, easy to use, low cost, and no contamination between experiments since disposable tips were used for the micropipettes. The MPE has the potential to be widely used in the future because it only requires a simple micropipette to perform all extraction processes. We believe that this technique can be a powerful tool for MALDI/MS analysis of biological samples and clinical applications.
Molecularly imprinted polymers for bisphenol A for HPLC and SPE from water and milk
Authors: Alexiadou Despina K. , Maragou Niki C. , Thomaidis Nikolaos S. , Theodoridis Georgios A. , Koupparis Michael A.
Published: July 2008

Molecularly imprinted polymers (MIPs) for bisphenol A (BPA) were prepared by two synthetic routes: semi‐covalent and noncovalent methodology. The molecular imprinting effect was evaluated using the polymers in HPLC and SPE. Polymers prepared with noncovalent mode were proven more effective. These polymers were applied in SPE facilitating selective retention of BPA from bottled water and milk. The developed sample preparation was simple and efficient comprising only dilution of milk and MISPE prior to LC‐MS analysis. Overall MISPE enhanced sample clean‐up. Compared with control nonimprinted polymers and conventional C18 SPE cartridges, the MIPs exhibited selective analyte recognition. The method provided quantitative BPA recoveries, very good reproducibility (% RSDs lower than 7%), and low LOD (0.2 ng/g). MIP interacts similarly with deuterated BPA allowing its use as internal standard in LC‐MS. The most critical parameters of MISPE were the organic content in loading–washing medium and the washing volume. Low flow rates in the elution step enhanced extraction recovery. Important advantages of the MIP were: the high breakthrough volumes (> 500 mL of water), high mass capacity (> 10 ng/mg of MIP sorbent), good linearity, and good stability in performance for over 35 cycles of use.
Multi‐residue methods for confirmatory determination of antibiotics in milk
Authors: Samanidou Victoria , Nisyriou Styliani
Published: July 2008

The prevalent use of antibiotics, e. g. sulphonamides, tetracyclines, β‐lactams, macrolides, aminoglycosides, etc., in dairy farming to prevent and treat microbial infections e. g. mastitis, can be a potential source of veterinary drug residues in milk. Antibiotic residues constitute a risk to human health, since they can cause allergic reactions in hypersensitive individuals or they may lead to the appearance of drug‐resistant bacteria. Analysis of these residues plays a key role in ensuring food safety. Regulatory agencies in the European Union and in other countries have established maximum residue limits and requirements concerning the performance of analytical methods and the interpretation of the results. This review describes the state of the art in the analytical strategies concerning the multi‐class as well as the multi‐residue analysis of antibiotics in milk. Since milk is a complex matrix due to its high protein and fat content, which often interfere in analytical procedures, special focus has been placed on sample preparation: extraction and clean‐up. Confirmation of antibiotic residues according to European Decision 657/2002/EC has been also discussed.
Application of the iodine–azide postcolumn reaction in RP‐HPLC for the determination of thioguanine in urine
Authors: Zakrzewski Robert
Published: July 2008

The study focuses on the analysis of a sensitive, selective, and simple postcolumn detection method for thioguanine determination, based on the sensitizing induction of thioguanine on iodine–azide reaction and the combination technique of HPLC. The analysis was accomplished in the optimum conditions for iodine–azide detection system and HPLC separation. The values for the linear range, the LOD, and DOQ amounted to 0.8–1.7, 0.4, and 0.5 nmol/mL urine, respectively.
Analysis of native carotenoid composition in orange juice using C30 columns in tandem
Authors: Dugo Paola , Herrero Miguel , Giuffrida Daniele , Ragonese Carla , Dugo Giacomo , Mondello Luigi
Published: July 2008

In the present contribution, a novel analytical approach based on using serial coupled conventional LC columns is proposed to the study of the native carotenoid composition of orange juice. The great difficulties that are found when analyzing complex carotenoid samples, due to the high natural variability of these compounds as well as to the presence of carotenoid esters are well documented. To overcome some of these limitations, we have developed a methodology including the study of both the saponified and the intact sample by means of two different LC‐DAD/APCI‐MS methods. The increase in the resolution and separation power obtained when using two serial coupled C30 columns is demonstrated, and significant increases in peak capacity have been achieved. By using this new methodology, 44 different carotenoids have been tentatively identified. Among them, several violaxanthin diesters have been directly identified in orange juice for the first time. The main carotenoids in orange juice were violaxanthin, lutein, luteoxanthin, 9‐cis‐antheraxanthin, and β‐cryptoxanthin. Some of them were found in both their free and esterified forms. To the best of our knowledge, this is the first application of serial couplings of C30 columns for the identification of the native carotenoid composition of natural matrices.
Stationary phases for chromatography prepared by ring opening metathesis polymerization
Authors: Buchmeiser Michael R.
Published: July 2008

The chemistry of metathesis polymerization‐derived stationary phases is summarized. Since both ring‐opening metathesis and 1‐alkyne polymerization triggered by well‐defined transition metal alkylidenes are living polymerization methods, they allow for the controlled and highly reproducible synthesis of stationary phases in terms of both the nature and total content of the functional group(s) of interest. In addition, the high functionality tolerance of these polymerization techniques allows for creating chromatographic supports with an unprecedented diversity in terms of functional groups that may be introduced. Their applications in various areas of separation science such as SPE, ion‐chromatography, RP chromatography, chiral chromatography, and the high‐performance liquid chromatographic separation of biomolecules are summarized. Within the context of the latter topic, special attention will be given to metathesis polymerization‐derived monolithic supports. Consideration will also be given to those aspects of polymer chemistry that are relevant to the separation performance of these supports.
Multidimensional liquid phase separations for mass spectrometry
Authors: Tomáš Roman , Klepárník Karel , Foret František
Published: July 2008

Large part of the current research in biology, medicine, and biotechnology depends on the analysis of DNA (genomics), proteins (proteomics), or metabolites (metabolomics). The advances in biotechnology also command development of adequate analytical instrumentation capable to analyze minute amounts of samples. The analysis of the content of single cells may serve as an example of ultimate analytical applications. Most of the separation techniques have been developed in the last three decades and alternative approaches are being investigated. At present, the main protocols for analyses of complex mixtures include 2‐DE (IEF) followed by electrophoresis in SDS polyacrylamide gel (SDS‐PAGE) and chromatographic techniques. Information‐rich techniques such as MS and NMR are essential for the identification and structure analysis of the analyzed compounds. High resolution separation of the individual sample components is often a prerequisite for success. High resolution proteomic analysis in the majority of laboratories still relies on the time consuming and laborious offline methods. This review highlights some of the important aspects of 2‐D separations including microfluidics.
Enantiomeric separation by using nano‐liquid chromatography with on‐column focusing
Authors: D'Orazio Giovanni , Fanali Salvatore
Published: July 2008

The present study shows a new nano‐liquid chromatographic method for β‐blocker enantiomers' separation. This method consists of using a capillary column packed with silica particles which were chemically modified with vancomycin. On‐column focusing allowed to inject relatively high sample volumes (1500 nL) increasing method sensitivity. The studied racemic compounds, namely atenolol, propranolol, oxprenolol, and metoprolol were dissolved in methanol and injected for chromatographic separation. The effect of injected sample volume was studied in the range of 50–2100 nL. Peak height of the two alprenolol enantiomers increased linearly up to 1500 nL. This volume was injected for validation and sample analysis. Under optimal experimental conditions, LODs and LOQs (LOD and LOQ for each alprenolol enantiomers) were 9.0 and 15.6 ng/mL, respectively. Calibration curves were linear in the studied range (9–250 ng/mL). The optimized method was applied to the analysis of a human plasma sample spiked with racemic alprenolol.
A cation‐exchange material for protein separations based on grafting of thiol‐terminated sulfopropyl methacrylate telomers onto hydrophilized monodisperse divinylbenzene particles
Authors: Nordborg Anna , Limé Fredrik , Shchukarev Andrei , Irgum Knut
Published: July 2008

A strong cation‐exchange separation material has been prepared from monodisperse divinylbenzene particles modified by a ”grafting to” approach, utilizing as anchoring points epoxy groups introduced onto the surface of the particles via oxidation of residual vinyl groups. The grafted chains consisted of thiol‐terminated telomers of sulfopropyl methacrylate prepared by iniferter mediated polymerization, and grafting was performed by reaction of the corresponding thiolate anion with the surface epoxy groups. Attachment through epoxy moieties that were subsequently converted into 2,3‐propanediol groups increased the hydrophilicity of the polymeric particles and incubation experiments showed no signs of the proteins denaturing on the column during an extended contact time of 1 h at room temperature. The performance of the grafted material was demonstrated by the chromatographic separation of cytochrome C, lysozyme, myoglobin, and ribonuclease A, in a cation‐exchange mode.