bluuebunny/crossref_metadata_2025_split huggingface dataset:
Sequential testing of duration data: the case of the Pennsylvania ‘reemployment bonus’ experiment
Authors: Bilias Yannis 
Published: August 2002

AbstractCost considerations and the need to report the results promptly make it desirable to examine data as it accumulates and to terminate an experimental study as soon as definite statistical conclusions can be drawn. These ideas are illustrated in a retrospective analysis of the Pennsylvania ‘Reemployment Bonus’ experiment. Recently developed large‐sample theory for a variety of sequentially computed score processes of time‐to‐event (duration) data with staggered entry enables one to construct stopping boundaries of a prescribed level of significance. The gains from the use of sequential methodology appear to be worth while. Copyright © 2000 John Wiley & Sons, Ltd.
Measuring predictability: theory and macroeconomic applications
Authors: Diebold Francis X. , Kilian Lutz 
Published: August 2002

AbstractWe propose a measure of predictability based on the ratio of the expected loss of a short‐run forecast to the expected loss of a long‐run forecast. This predictability measure can be tailored to the forecast horizons of interest, and it allows for general loss functions, univariate or multivariate information sets, and covariance stationary or difference stationary processes. We propose a simple estimator, and we suggest resampling methods for inference. We then provide several macroeconomic applications. First, we illustrate the implementation of predictability measures based on fitted parametric models for several US macroeconomic time series. Second, we analyze the internal propagation mechanism of a standard dynamic macroeconomic model by comparing the predictability of model inputs and model outputs. Third, we use predictability as a metric for assessing the similarity of data simulated from the model and actual data. Finally, we outline several non‐parametric extensions of our approach. Copyright © 2001 John Wiley & Sons, Ltd.
Stochastic frontier models with random coefficients
Authors: Tsionas Efthymios G. 
Published: August 2002

AbstractThe paper proposes a stochastic frontier model with random coefficients to separate technical inefficiency from technological differences across firms, and free the frontier model from the restrictive assumption that all firms must share exactly the same technological possibilities. Inference procedures for the new model are developed based on Bayesian techniques, and computations are performed using Gibbs sampling with data augmentation to allow finite‐sample inference for underlying parameters and latent efficiencies. An empirical example illustrates the procedure. Copyright © 2002 John Wiley & Sons, Ltd.
Genetic toxicology studies with glutaraldehyde
Authors: Vergnes Jane S. , Ballantyne Bryan 
Published: August 2002

AbstractGlutaraldehyde (GA; CAS no. 111‐30‐8) has a wide spectrum of industrial, scientific and biomedical applications, with a potential for human exposure particularly in its biocidal applications. The likelihood for genotoxic effects was investigatedin vitroandin vivo. ASalmonella typhimuriumreverse mutation assay showed no evidence for mutagenic activity with strains TA98, TA1535, TA1537 and TA1538, with or without metabolic activation. However, there was a weak mutagenic response (1.9–2.3‐fold at the highest non‐toxic concentration) with TA100 in the presence of metabolic activation. In a Chinese hamster ovary (CHO) forward gene mutation assay (HGPRT locus) there were no consistent, statistically significant, reproducible or dosage‐related increases in the frequency of 6‐thioguanine resistant cells. There were no reproducible or dosage‐related increases in sister chromatid exchanges in anin vitrotest in CHO cells. Anin vitrocytogenetics study in CHO cells showed no evidence for an increase in chromosomal aberrations on treatment with GA, either in the presence or absence of metabolic activation.In vivo, a mouse peripheral blood micronucleus test showed no increase in micronucleated polychromatophils at sampling times of 30, 48 and 72 h after acute gavage dosing with GA at 40, 80 and 125 mg kg−1(corresponding to 25, 50 and 85% of theLD50). The absence of anin vivoclastogenic potential was confirmed by no increase in chromosomal aberrations in a rat bone marrow cytogenetics study with sampling at 12, 24 and 48 h after acute gavage dosing with GA (12.5, 30 or 60 mg kg−1with males, and 7.5, 20 or 40 mg kg−1with females). Thus, in this series of tests, GA produced genotoxic effectsin vitroonly in a bacterial reverse mutation assay with no evidence forin vivogenotoxicity. Copyright © 2002 John Wiley & Sons, Ltd.
Feasibility study using a natural compound (reuterin) produced by Lactobacillus reuteri in sterilizing and crosslinking biological tissues
Authors: Chen Chiun‐Nan , Sung Hsing‐Wen , Liang Hsiang‐Fa , Chang Wen‐Hsiang 
Published: August 2002

AbstractBioprostheses derived from biological tissues have to be fixed and subsequently sterilized before they can be implanted in humans. Currently available crosslinking agents and sterilants used in the fixation or sterilization of biological tissues such as glutaraldehyde and formaldehyde are all highly cytotoxic, which may impair the biocompatibility of bioprostheses. Therefore, it is desirable to provide an agent suitable for use in biomedical applications that is of low cytotoxicity and may form sterile and biocompatible crosslinked products. To achieve this goal, a natural compound (reuterin), produced by Lactobacillus reuteri in the presence of glycerol, was used by our group. It is known that reuterin has antibacterial, antimycotic, and antiprotozoal activities. Additionally, as in the case with formaldehyde, reuterin may react with the free amino groups in biological tissues by using its aldehyde functional group. Therefore, it was speculated that reuterin could be used as a crosslinking agent and a sterilant for biological tissues in the same way as glutaraldehyde and formaldehyde. In the study, the production of reuterin, produced by Lactobacillus reuteri under control conditions, was reported. Preparative chromatography was used to purify reuterin. Also, the minimal inhibitory concentration and minimal bactericidal concentration of reuterin and its antimicrobial activity on a contaminated tissue were investigated. In addition, the cytotoxicity of reuterin was evaluated. Glutaraldehyde, the most commonly used sterilant in the sterilization of biological tissues, was employed as a control. Furthermore, the feasibility of using reuterin as a crosslinking agent in fixing biological tissues was studied. Fresh and the glutaraldehyde‐fixed tissues were used as controls. The results obtained in the minimal inhibitory concentration and minimal bactericidal concentration studies and in the sterilization study of a contaminated tissue indicated that the antimicrobial activity of reuterin is significantly superior to its glutaraldehyde counterpart. In addition, the results obtained in the 3‐(4,5‐dimethylthiazol‐yl)‐2,5‐diphenyltetrazolium bromide assay showed that reuterin is significantly less cytotoxic than glutaraldehyde. Additionally, it was found that reuterin is an effective crosslinking agent for biological tissue fixation. The reuterin‐fixed tissue had comparable free amino group content, denaturation temperature, and resistance against enzymatic degradation as the glutaraldehyde‐fixed tissue. In conclusion, the results obtained in this study indicate that reuterin is an effective agent in the sterilization and fixation of biological tissues. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 360–369, 2002
The use of liposomal enrofloxacin for intracellular infections in Kangal dogs and visualization of phagocytosis of liposomes
Authors: Deĝim Zelihagül , Deĝim Tuncer , Bas Levent , Elmas Muammer 
Published: August 2002

AbstractIt is difficult to treat intracellular infections because of the intrinsic resistance of the microorganism to most antibiotics. Moreover, these microorganisms can survive in phagocytic cells (macrophages and neutrophils). In this study, our aims were to encapsulate an antibiotic in liposomes, which will be phagocytized as well as the microorganisms in the phagocytic cell (because liposomes were prepared using lipids which have an antigenic activity and they can be phagocytized, thus, the active substance can be transferred into the cell), and to visualise with microscopy the phagocytic activity of macrophages and neutrophils to liposomes. MLV (multilamellar vesicles) fluorescein‐labeled liposomes were prepared and incubated with isolated Kangal shepherd dog macrophages and neutrophils. The phagocytosis of liposomes by monocytes was visualized step by step under the microscope. Liposomes were also observed phagocytized after incubation with neutrophils. Enrofloxacin was chosen as a model drug. Neutrophils and macrophages were isolated from Kangal shepherd dogs and infected withStaphylococcus aureus,and their phagocytic activities (PA) and microbicidal activities (MA) were determined. PA and MA values were redetermined and compared when enrofloxacin formulations were used. Liposomal enrofloxacin was found to be more effective. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 61: 246–251, 2002
Long‐term effects of four extraction media on the fluoride release from four polyacid‐modified composite resins (compomers) and one resin‐modified glass‐ionomer cement
Authors: Behrend B. , Geurtsen W. 
Published: August 2002

AbstractIt was the aim of the present experiments to evaluate the fluoride leaching of four compomers and one resin‐modified glass‐ionomer cement (gic) into aqueous media over a 1‐year period. Various extraction/equilibrium solutions were applied to simulate important intraoral parameters. Specimens of Dyract™, Compoglass™ F, F2000™, one experimental compomer, and the resin‐modified gic Fuji II LC™ were stored for 366 days in distilled water (I), acidic medium (pH 4.2) (II), neutral medium (pH 7.0) (III), or solution III supplemented with 1.6 u/mL porcine liver esterase (IV). Equilibrium media were changed and fluoride concentration was measured every 48 h (first 30 d), thereafter each week (twice), then every 14 d (three times), and finally every 28 d up to a total period of 1 year. Data were statistically analyzed for significant differences by means of Scheffe′ tests (p < 0.05). The gic and the compomers leached significantly more fluoride into the acidic solution in the initial phase compared to the other media (p < 0.05). Cumulative fluoride release from all materials (except experimental compomer) was elevated because of esterase activity (p <0.05). Measurable but low quantities of fluoride were segregated into all media during the 1‐year period. But no significantly different long‐term fluoride release into the various media from the investigated materials was found. The data indicate that plaque‐associated organic acids or salivary hydrolases may increase initial fluoride release from resin‐modified gics or compomers in the oral cavity. Because long‐term fluoride release from all materials decreased to low concentrations within a 30‐day period, their caries preventive effect remains questionable. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 631–637, 2001
Pore diameter of more than 100 μm is not requisite for bone ingrowth in rabbits
Authors: Itälä Ari I. , Ylänen Heimo O. , Ekholm Clifford , Karlsson Kaj H. , Aro Hannu T. 
Published: August 2002

AbstractThe optimal pore size for bone ingrowth is claimed to be 100–400 μm. With the use of a highly standardized experimental model, the present study reevaluated whether a pore size of 100 μm is the threshold value for bone ingrowth into porous structures under non‐load‐bearing conditions. Titanium triangle‐shaped plates 250 or 500 μm thick were perforated with the use of a laser in order to create standard‐sized holes (∅︁ 50, 75, 100, and 125 μm) in multiple rows. The amount of bone ingrowth through the implant holes was studied in the cancellous bone of the distal rabbit femur. Twelve weeks after implantation, detailed analysis of bone ingrowth was performed with computerized image analysis of backscattered electron imaging techniques of scanning electron microscopy. The results showed that the amount of ingrown new bone was independent of the pore size and implant thickness. The median value for bone ingrowth varied between 64 and 78%. A striking feature was the formation of secondary osteonal structures even in the smallest holes. Based on these results, there is no threshold value for new bone ingrowth in pore sizes ranging from 50 to 125 μm under non‐load‐bearing conditions. © 2001 John Wiley & Sons, Inc. J Biomed Mater Res (Appl Biomater) 58: 679–683, 2001
Localization of metallic ions with gingival fibroblast subcellular fractions
Authors: Messer Regina L. W. , Lucas L. C. 
Published: August 2002

AbstractNickel‐based alloys have been in use since the 1930s; however, there are concerns regarding the release of metal ions (Be+2, Cr+6, Cr+3, Ni+2, Mo+6) from these alloys into surrounding tissues. Therefore, the objective of this study was to determine the cellular location and accumulation of ions using atomic absorption spectroscopy and correlate location with the cytotoxic, morphologic, and ultrastructural evaluations reported previously. Human gingival fibroblasts were exposed to the metal ions for 72 h. Controlled atomic absorption spectroscopy studies were used to determine the intracellular location of these ions reported as parts per million metal ions per milligram protein. Enzymatic markers were shown to correspond to the appropriate fraction indicating success in fractionation of the gingival fibroblasts. These results correspond with the cytotoxic, morphologic, and ultrastructural alterations reported previously for fibroblasts exposed to these ions. The highest concentration of beryllium ions occurred in the low‐density molecule fraction, where lipofuscin granules were found, which has been shown to contain metal ions. The highest concentrations of hexavalent chromium ions occurred in the plasma membrane and nuclear fractions followed by the mitochondria fraction, which is supported by the ions’ ability to oxidize to trivalent chromium accumulating at the membrane as well as the alterations in nuclear and mitochondrial function. For trivalent chromium, the highest concentrations occurred in the low‐density molecule and the plasma membrane fractions, which correlates with the ions’ inability to readily cross membranes. The highest concentration of molybdenum ions occurred in the plasma membrane fraction correlating with alterations in membrane morphology and increased numbers of myelin figures. The highest concentration of nickel ions was associated with the cytosol fraction where lipid droplets seen in the transmission electron micrographs were located. The current study demonstrates that a successful subcellular fractionation was obtained on gingival fibroblasts and that the location of metallic ions within the fractions correlated with cellular alterations reported previously. © 2001 Wiley Periodicals, Inc. J Biomed Mater Res 59: 466–472, 2002
Dynamic changes in cytokine levels in serum and synovial fluid following filtration leukocytapheresis therapy in patients with rheumatoid arthritis
Authors: Hidaka Toshihiko , Suzuki Kimihiro , Kawakami Makoto , Okada Makoto , Kataharada Kouji , Shinohara Tadashi , Takamizawa‐Matsumoto Mitsuyo , Ohsuzu Fumitaka 
Published: August 2002

AbstractWe attempted to determine whether various cytokine levels in the serum and synovial fluid (SF) of rheumatoid arthritis (RA) patients are influenced by the performance of filtration leukocytapheresis (LCP). The filtration LCP procedure that used a Cellsorba® column (LCP group: n=22; responder subgroup: n=17, non‐responder subgroup: n=5) or sham apheresis (control group; n=7) was repeated three times at 1‐week intervals. Serum (LCP group, n=22; control group, n=7) and SF (LCP group, n=6; control group, n=3) samples were collected before and after LCP. Levels of tumor necrosis factor α (TNFα), interleukins (IL‐1β, IL–2, IL‐6, IL‐8, IL‐10, and IL‐15), granulocyte–macrophage colony–stimulating factor (GM‐CSF), monocyte chemoattractant protein–1 (MCP‐1), RANTES were measured by an enzyme‐linked immunosorbent assay. Serum TNFα, IL‐15, and RANTES were significantly reduced only in the LCP group. Serum IL‐10 significantly increased only in the LCP group. In the LCP subgroup, serum IL‐15, GM‐CSF, and RANTES levels were reduced significantly, while serum IL‐10 levels increased significantly only in the responder group after treatment. Serum TNFα levels were reduced significantly in both subgroups. Changes in serum IL‐10 correlated positively with the improvement of patient's assessment of pain and global severity, and physician's assessment of global severity. These results indicate that the removal of leukocytes from the peripheral blood of RA patients provokes dynamic changes in some cytokine levels in the serum and/or synovial fluid. These changes may explain some of the mechanisms by which the articular symptoms are improved by filtration LCP. J. Clin. Apheresis. 16:74–81, 2001. © 2001 Wiley‐Liss, Inc.
Heat shock proteins of chicken lens
Authors: Bagchi M. , Ireland M. , Katar M. , Maisel H. 
Published: August 2002

AbstractThe presence of heat shock proteins HSP‐40, HSP‐70, and HSc‐70 in adult and embryonic chicken lenses were determined. The epithelium, cortex, and nucleus of adult chicken lens were separated and tested for the presence of heat shock proteins (hsps) by western blot, using specific antibodies for HSP‐40, HSP‐70, and HSc‐70. Water soluble (WSF) and water insoluble fractions (WIF) of embryonic chicken lenses were isolated and tested for the presence of HSP‐40, HSP‐70, and HSc‐70 by immunoblot. Embryonic chicken lens sections were also analyzed for the presence of heat shock proteins by immunoflorescence technique. Data obtained from these experiments revealed that HSP‐40, HSP‐70, and HSc‐70 are present in all areas of both adult and embryonic chicken lens. Presence of hsps protein in the deep cortex and nucleus is intriguing as no detectable metabolic activities are reported in this area. However it can be proposed that hsps HSP‐40, HSP‐70, and HSc‐70 can interact with protein of these areas and protect them from stress induced denaturation. J. Cell. Biochem. 82:409–414, 2001. © 2001 Wiley‐Liss, Inc.
Multiple role of reactive oxygen species in the arterial wall
Authors: Napoli Claudio , de Nigris Filomena , Palinski Wulf 
Published: August 2002

AbstractIncreased oxidative stress plays an important role in vascular dysfunction and atherogenesis. Both systemic factors, such as hypercholesterolemia and hyperglycemia, and local factors, such as activation of macrophages and T cells, may contribute to oxidative stress. Oxidation of lipids in lipoproteins and cell membranes leads to functionally important modifications of proteins that affect their recognition by cell surface receptors and protein–protein interactions within the cell, including DNA binding. Oxidized LDL and extracellular oxidation modulate oxidation‐sensitive signaling pathways, but it is not clear to what extent this results from receptor‐mediated activation or from direct effects on the intracellular redox‐balance. Extensive evidence indicates that reactive oxygen species (ROS) regulate gene expression by modulating a large number of transcription factors, including the nuclear transcription factor kappa B (NFκB), the peroxisome proliferator activated receptorγ (PPARγ), and pathways linked to apoptosis. It is also increasingly recognized that cell differentiation and proliferation, cytokine expression, and programmed cell death are determined by the interactions between oxidation‐sensitive regulatory pathways previously thought to lead to distinct outcomes. Because hypercholesterolemia exerts pro‐oxidant effects both intra‐ and extracellularly and because increased ROS formation affects vascular reactivity and atherogenesis by modulating multiple signaling pathways and transcriptional events, future investigations of its atherogenic mechanisms should place greater emphasis on the net effect of such modulation on the expression of a large spectrum of genes. One way of doing this will be by defining clusters of genes responding to hypercholesterolemic stimuli—or interventions with structurally unrelated antioxidants—in analogous ways, irrespective of what regulatory pathway they are controlled by. Microarray technologies that allow simultaneous assessment of large numbers of genes may provide a tool for this approach. J. Cell. Biochem. 82: 674–682, 2001. © 2001 Wiley‐Liss, Inc.
Theoretical calculation of the coiled‐coil stability in water in the context of its possible use as a molecular rack
Authors: Orzechowski Marek , Cieplak Piotr , Piela Lucjan 
Published: August 2002

AbstractThe coiled‐coil stability and rigidity may be of importance for molecular electronics (electronically bistable molecules). The coiled‐coil binding free energy has been calculated using molecular dynamics (MD). The energy has been computed as a difference of the appropriate free energies; derived for the coiled‐coil and isolated α‐helices separately. All MD simulations have been performed using an explicit model of the solvent, whereas the continuum solvent approach has been applied to analyze the MD trajectories. The computed stability of the coiled‐coil is of the order of −87 kcal/mol, i.e., about −1.2 kcal/mol per amino acid residue, and arises mainly from the electrostatic interactions and hydrophobic effect. The entropy term has been roughly estimated to be of the order of −22 kcal/mol. This assures that coiled‐coil polypeptides may be used as a stable molecular scaffolding. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 106–110, 2002
Molecular detection and identification of an enterovirus during an outbreak of aseptic meningitis
Authors: Siafakas Nikolaos , Georgopoulou Amalia , Markoulatos Panayotis , Spyrou Niki , Stanway Glyn 
Published: August 2002

AbstractStool samples from sixteen cases of children with meningitis originating from four different and geographically isolated parts of Greece were investigated for enteroviruses. The conventional method of cell culture in four different cell lines was initially used for the isolation of enteroviruses. The results showed a cytopathic effect &lpar;CPE&rpar; in all cases after two, or even more successive passages in only one cell line &lpar;RD&rpar;, although a less&hyphen;than&hyphen;satisfactory CPE was obtained in many cases. Seroneutralization with RIVM mixed hyperimmune antisera followed and the isolates were typed as Coxsackie B viruses. The method of RT&hyphen;PCR with enterovirus&hyphen;specific primers targeted to the highly conserved 5&prime;&hyphen;UTR of the genome was initially used for the detection of enteroviruses from the inoculated cell cultures. A positive RT&hyphen;PCR result was obtained for all of the clinical samples rapidly and accurately and the isolates were further characterized with the aid of Restriction Fragment Length Polymorphism &lpar;RFLP&rpar; analysis and Single Strand Conformation Polymorphism analysis &lpar;SSCP&rpar; of the amplicons. The RFLP analysis showed first of all that the isolates had an identical restriction pattern with Coxsackie B5 Faulkner reference strain with 4 out of 5 restriction enzymes and secondly, both RFLP and SSCP analysis indicated the epidemiological association of the isolates. The speed of the molecular methodology that was used in comparison with the conventional methods and its possible significance for the description of virus evolution and circulation in the populations is discussed. J. Clin. Lab. Anal. 15:87&ndash;95, 2001. &copy; 2001 Wiley&hyphen;Liss, Inc.