bluuebunny/crossref_metadata_2025_split huggingface dataset:
Protective effects of antioxidants on micronuclei induced by irradiated 9‐fluorenone/N,N‐dimethyl‐p‐toluidine in CHO cells
Authors: Li Yi‐Ching , Huang Fu‐Mei , Lee Shiuan‐Shinn , Lin Ruey‐Hseng , Chou Ming‐Yung , Chang Yu‐Chao 
Published: April 2007

Abstract9‐Fluorenone (9F), the aromatic photosensitizer, is widely used as an initiator in visible‐light (VL) cured resin systems. There is growing concern that 9F may produce genetic damage by inducing mutation. In this study, 9F in the presence or absence of reducing agent N,N‐dimethyl‐p‐toluidine (DMT) with or without VL irradiation was analyzed for the induction of chromosomal aberrations indicated by micronuclei (MN) induced in CHO cells. Our data demonstrated that a dose‐related increase in the frequency of MN and prolonged cell cycles in 9F with or without DMT in the presence or absence of VL irradiation (p < 0.05). The rank orders with respect to genotoxicity and cytotoxicity were found to be as follows: 9F/DMT +VL > 9F/DMT = 9F + VL > 9F. To determine whether oxidative stress could modulate MN induced by 9F/DMT with or without VL irradiation in CHO cells, cells were pretreated with N‐acetyl‐L‐cysteine (NAC), ascorbic acid, and α‐tocopherol. The pretreatment with antioxidants could diminish not only the prolonged cell cycle but also the decreased frequency of MN which is induced by 9F with or without DMT in the presence or absence of VL irradiation in CHO cells (p < 0.05). Our findings provide the evidences for the induction of MN by 9F in the presence or absence of DMT with or without VL irradiation in CHO cells, indicating clastogenic activity of 9F/DMT in vitro. These antioxidants act as the antagonists against the genotoxicity and cytotoxicity of 9F/DMT. Thus, leaching photoinitiator and reducing agent might be contributing the sources of oxidative stress. © 2007 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 2008
Nmp4/CIZ contributes to fluid shear stress induced MMP‐13 gene induction in osteoblasts
Authors: Charoonpatrapong‐Panyayong Kanokwan , Shah Rita , Yang Jieping , Alvarez Marta , Pavalko Fredrick M. , Gerard‐O'Riley Rita , Robling Alexander G. , Templeton Evan , Bidwell Joseph P. 
Published: April 2007

AbstractThe expression of matrix metalloproteinase‐13 (MMP‐13), involved in bone turnover, is elevated in stretched MC3T3‐E1 osteoblast‐like cells. Strain‐mediated forces impact bone remodeling due in large part to the movement of fluid through the canalicular‐lacunar network. The resulting fluid shear stress (FSS) over the surface membranes of bone cells initiates bone remodeling. Although the nuclear events mediating putative FSS‐induced changes in osteoblast MMP‐13 transcription are unknown, previous studies with bone cells suggest an overlap between osteoblast FSS‐ and PTH‐induced signal response pathways. MMP‐13 PTH response is regulated by a 110 bp 5′ regulatory region, conserved across the mouse, rat, and human genes, that supports the binding of numerous transcription factors including Runx2, c‐fos/c‐jun, Ets‐1, and nuclear matrix protein 4/cas interacting zinc finger protein (Nmp4/CIZ) a nucleocytoplasmic shuttling trans‐acting protein that attenuates PTH‐driven transcription. Nmp4/CIZ also binds p130cas, an adaptor protein implicated in mechanotransduction. Here we sought to determine whether Nmp4/CIZ contributes to FSS‐induced changes in MMP‐13 transcription. FSS (12 dynes/cm2, 3–5 h) increased MMP‐13 promoter‐reporter activity approximately two‐fold in MC3T3‐E1 osteoblast‐like cells attended by a comparable increase in mRNA expression. This was accompanied by a decrease in Nmp4/CIZ binding to its cis‐element within the PTH response region, the mutation of which abrogated the MMP‐13 response to FSS. Interestingly, FSS enhanced Nmp4/CIZ promoter activity and induced p130cas nuclear translocation. We conclude that the PTH regulatory region of MMP‐13 also contributes to FSS response and that Nmp4/CIZ plays similar but distinct roles in mediating hormone‐ and FSS‐driven induction of MMP‐13 in bone cells. J. Cell. Biochem. 102: 1202–1213, 2007. © 2007 Wiley‐Liss, Inc.
Electrophysiological characterization of neural stem/progenitor cells during in vitro differentiation: Study with an immortalized neuroectodermal cell line
Authors: Jelitai M. , Anderová M. , Chvátal A. , Madarász E. 
Published: April 2007

AbstractDespite the accumulating data on the molecular and cell biological characteristics of neural stem/progenitor cells, their electrophysiological properties are not well understood. In the present work, changes in the membrane properties and current profiles were investigated in the course of in vitro‐induced neuron formation in NE‐4C cells. Induction by retinoic acid resulted in neuronal differentiation of about 50% of cells. Voltage‐dependent Na+ currents appeared early in neuronal commitment, often preceding any morphological changes. A‐type K+ currents were detected only at the stage of network formation by neuronal processes. Flat, epithelial‐ like, nestin‐expressing progenitors persisted beside differentiated neurons and astrocytes. Stem/progenitor cells were gap junction coupled and displayed large, symmetrical, voltage‐independent currents. By the blocking of gap junction communication, voltage‐independent conductance was significantly reduced, and delayed‐rectifying K+ currents became detectable. Our data indicate that voltage‐independent symmetrical currents and gap junction coupling are characteristic physiological features of neural stem and progenitor cells regardless of the developmental state of their cellular environment. © 2007 Wiley‐Liss, Inc.
On the distribution of VOTAW's likelihood ratio criterion L for testing the bipolarity of a covariance matrix
Authors: Consul P. C. 
Published: April 2007

AbstractIn this paper the exact distribution function of Votaw's likelihood ratio criterion L has been obtained in the form of an infinite series by applying Mellin's transformation on the moments and then by using the asymptotic expansion for log Γ(x + h). The author has actually calculated the values of the constants for some particular cases and has shown that the first four or five terms give a high degree of accuracy. An expression for the Integral probability of the distribution has also been obtained.
On Certain Recurrence Relations
Authors: Srivastava Aruna , Gupta K. C. 
Published: April 2007

AbstractIn this paper first we establish six recurrence relations for the H‐function with the help of certain formulae concerning generalized BESSEL function. Later on, we obtain recurrence relations for MEIJER'S G‐function, GAUSS'S hypergeometric function and BESSEL function. On account of the general character of the H‐function, recurrence relations for other special functions can also be obtained as special cases of our results. Two well‐known results obtained earlier by Prof. MEIJER follow as special cases of our findings.
Über die Kreuzungszahl vollständiger, n‐geteilter Graphen
Authors: Harborth Heiko 
Published: April 2007

AbstractLet K(x1, x2, ⃛, xn) be a graph without loops or multiple edges, the complement of which consists of n disjoint complete graphs of x1, x2, ⃛, xn vertices. In this paper a class of mappings of K(x1, ⃛, xn) onto the Euclidean plane is described. The minimum number of intersection points of edges for these mappings is determined. This number also involves an upper bound for the so‐called crossing number cr(x1, ⃛, xn), being the minimum number of intersection points of edges for all mappings of K(x1, ⃛, xn) onto the Euclidean plane (see (28)). Equality in (28) is conjectured.
On Certain Recurrence Relations II
Authors: Srivastava Aruna , Gupta K. C. 
Published: April 2007

AbstractThe aim of this paper is to obtain five interesting and new recurrence relations for KAMPÉ‐DE‐FÉRIET function. On account of the general nature of this function, recurrence relations for generalized hypergeometric function follow as special cases of the main results. Corresponding recurrence relations for 2F2 have also been recorded. These recurrence relations are quite interesting and have not been recorded so far. Later on we obtain interesting and new recurrence relations involving 1F2 from the earlier mentioned relations for 2F2 with the help of confluence principle. Finally by specializing the parameters we obtain various interesting recurrence relations for BESSEL function and hypergeometric function 1F2. Some of the recurrence relations recorded in this paper may find application in Physics and Applied Mathematics. The special cases of our results yield known recurrence formulae for various special functions.
Extensions of an Euler's Integral Through Statistical Techniques
Authors: Mathai A. M. , Saxena R. K. 
Published: April 2007

AbstractExtensions of the Euler's integral ([4], p. 59 (10)) are given in this article. A statistical technique is used to derive the results. The exact density of a product of n stochastically independent Beta variates is obtained through two different methods, namely, through algebraic trans formations and through a moment sequence. From the unique existence of the density function, a number of results are obtained by equating the density obtained by the two methods. The technique developed in this article can be used in other situations as well.
Molecular description of a 3D in vitro model for the study of epithelial ovarian cancer (EOC)
Authors: Zietarska Magdalena , Maugard Christine M. , Filali‐Mouhim Abdelali , Alam‐Fahmy Mona , Tonin Patricia N. , Provencher Diane M. , Mes‐Masson Anne‐Marie 
Published: April 2007

AbstractEpithelial ovarian cancer (EOC) cell lines are useful tools for the molecular and biological characterization of ovarian cancer. The use of an in vitro multidimensional (3‐D) culture model recapitulates some of the growth conditions encountered by tumor cells in vivo. Here we describe a molecular comparison of spheroid based 3D EOC models versus monolayer cultures and xenografts using cell lines from malignant ovarian tumors (TOV‐21G and TOV‐112D) and ascites (OV‐90) previously established and characterized in our laboratory. Gene expression analyses of the three models were performed using the Affymetrix HG‐U133A high density DNA array. Cluster analysis identified a set of genes that stratified expression profiles from the EOC cell lines grown as spheroids and xenografts from that of monolayer cultures. The gene expression analysis results were validated by Q‐PCR analyses on an independent set of RNAs. Differential expression observed for theS100A6gene between the monolayer, spheroid cultures and xenografts was confirmed at the protein level by immunohistochemistry. The analysis was extended to various ovarian tumor tissues using an EOC tissue array. This result represents an example of a gene that, if studied in vitro, is more representative of the in vivo disease in a 3D model rather than the monolayer culture. Identification of genes in spheroid models that mimic the in vivo tumor gene expression patterns may allow a better understanding of the community effect observed in human disease that is determined by direct or indirect interactions of cells with their environment or other surrounding cells. © 2007 Wiley‐Liss, Inc.
Morphology and ultrastructure of differentiating three‐dimensional mammalian skeletal muscle in a collagen gel
Authors: Rhim Caroline , Lowell Dorothy A. , Reedy Mary C. , Slentz Dorothy H. , Zhang Sarah J. , Kraus William E. , Truskey George A. 
Published: April 2007

AbstractBecause previous studies of three‐dimensional skeletal muscle cultures have shown limited differentiation, the goal of this study was to establish conditions that would produce mature sarcomeres in a mammalian‐derived skeletal muscle construct. We evaluated the differentiation of bioartificial muscles generated from C2C12 myoblasts in a collagen gel cultured under steady, passive tension for up to 36 days. Staining for alpha‐actinin, myosin, and F‐actin indicated the presence of striated fibers as early as 6 days post‐differentiation. Electron microscopy at 16 days post‐differentiation revealed multinucleated myotubes with ordered, striated myofibers. At 33 days, the cultures contained collagen fibers and showed localization of paxillin at the fiber termini, suggesting that myotendinous junctions were forming. The present study demonstrates mature muscle synthesis in a three‐dimensional system using a pure mammalian myoblast cell line. Our results suggest that this culture model can be used to evaluate the effects of various mechanical and biochemical cues on muscle development under normal and pathological conditions. Muscle Nerve, 2007
The role of the printed answer in programmed instruction
Authors: Geis George L. , Jacobs William , Spencer Dwight , Nielsen Susan 
Published: April 2007

AbstractUsing a variety of programmed materials, this series of studies showed that students observed available answers in the program far less than 100% of the time. Answer observing was found to be correlated with student error on the related frame. The view that the printed answer in a program is always a reinforcer for the preceding response(s) is severely questioned.
CASINO V2.42—A Fast and Easy‐to‐use Modeling Tool for Scanning Electron Microscopy and Microanalysis Users
Authors: Drouin Dominique , Couture Alexandre Réal , Joly Dany , Tastet Xavier , Aimez Vincent , Gauvin Raynald 
Published: April 2007

AbstractMonte Carlo simulations have been widely used by microscopists for the last few decades. In the beginning it was a tedious and slow process, requiring a high level of computer skills from users and long computational times. Recent progress in the microelectronics industry now provides researchers with affordable desktop computers with clock rates greater than 3 GHz. With this type of computing power routinely available, Monte Carlo simulation is no longer an exclusive or long (overnight) process. The aim of this paper is to present a new user‐friendly simulation program based on the earlier CASINO Monte Carlo program. The intent of this software is to assist scanning electron microscope users in interpretation of imaging and microanalysis and also with more advanced procedures including electron‐beam lithography. This version uses a new architecture that provides results twice as quickly. This program is freely available to the scientific community and can be downloaded from the website: www.gel.usherb.ca/casino. SCANNING 29: 000‐000, 2007. © 2007 Wiley Periodicals, Inc.
Mantel‐haenszel statistics and direct standardization
Authors: Woolson Robert F. , Bean Judy A. 
Published: April 2007

AbstractThis paper demonstrates that the Mantel‐Haenszel chi‐square statistic may be employed to test the equality of two directly standardized rates. For certain epidemiological applications, this eliminates the need for special computer programs to contrast two directly standardized rates. Furthermore, since the weights are determined entirely by the data there is the advantage of avoiding the selection of an external standard population. Data analysts who compare two groups of rates with the Mantel‐Haenszel chi‐square statistic may view this statistic as a comparative measure of two directly adjusted rates.
The design of a sequential clinical trial for the comparison of two lung cancer treatments
Authors: Jones D. R. , Newman C. E. , Whitehead J. 
Published: April 2007

AbstractThe steps in designing a controlled trial to evaluate a new treatment for inoperable carcinoma of the bronchus are described. The principal outcome measure is survival time from treatment allocation, and the duration of the trial is determined by application of the sequential logrank test. The detailed determination of the stopping rule and the arrangements for analyses are described.
Age, period and cohort models applied to cancer mortality rates
Authors: Osmond C. , Gardner M. J. 
Published: April 2007

AbstractWe develop the application of age, period and cohort models to the representation of tables of age‐ and period‐specific rates. A derivation is given by way of a familiar graphical technique. The identifiability problem is discussed, identification techniques are reviewed and a new approach is recommended that is based upon the success of the three two‐variable submodels. Other constraints are introduced that enhance interpretation. Examples are given for two sites of cancer. This approach is contrasted with other methods designed to demonstrate trends. Finally, standard errors of the parameters and tests of goodness of fit are discussed.
The use of background data in the analysis of covariance
Authors: Shirley Eryl A. C. 
Published: April 2007

AbstractThe advantages and disadvantages of using extraneous information about the relationship between variate and covariate in analysis of covariance are examined. The problem is considered both theoretically and by a simulation study. It is found that the usefulness of extraneous information in increasing the precision of analysis of covariance can be assessed using simple formulae.
The role of randomization in clinical trials
Authors: Armitage Peter 
Published: April 2007

AbstractRandom assignment of treatments is an essential feature of experimental design in general and clinical trials in particular. It provides broad comparability of treatment groups and validates the use of statistical methods for the analysis of results. Various devices are available for improving the balance of prognostic factors across treatment groups. Several recentt initiatives to diminish the role of randomization are seen as being potentially misleading. Randomization is entirely compatible with medical ethics in circumstances when the treatment of choice is not clearly identified.
On the standard error of the probability of a particular diagnosis
Authors: Machin D. , Dennis N. R. , Tippett P. A. , Andrews V. 
Published: April 2007

AbstractApproximate standard errors of the probability of a particular diagnosis are given for the predictive and estimative methods described by Aitchison and Dunsmore.1 An example used in the detection of carriers of Duchenne muscular dystrophy (DMD) is given for illustration.
Discriminant analysis based on multivariate response curves: A descriptive approach to dynamic allocation
Authors: Albert Adelin 
Published: April 2007

AbstractWe examine the problem of discriminating between two groups in the context of multivariate response curves observed over a specified time interval. We propose a descriptive solution for the case where one can determine the response curves by linear interpolation between successive observations. Unlike most previously reported methods that use only the current multivariate observation, our approach accounts for the history of the process. Moreover the method has the potential advantage of being applicable dynamically, as one observes the multivariate response curve. Finally, the method demonstrates simplicity and flexibility, two important features for successful, routine, clinical application.
Determining reference (‘normal’) limits in medicine: An application
Authors: Bezemer P. D. , Netelenbos J. C. , Mulder C. , Theune J. A. , Stamhuis I. H. , Straus J. P. 
Published: April 2007

AbstractWe provide an account of a study to assess reference limits for eight routine laboratory determinations at the Academic Hospital of the Free University, Amsterdam and emphasize methodological issues rather than results. We argue that reference limits have use mainly in the first phase of the diagnostic process. Reference and target populations should be grossly comparable, and therefore patients (after slight selection) could well serve as references. However, we found major differences between in and out‐patients, so we suggest that this factor, together with age and sex, be taken into account. To arrive at reliable limits, the size of the reference sample should be at least 100. Laboratory reports should provide percentiles, which enable a more flexible decision than do fixed limits.
The analysis using genstat of anaemia, sugar intake and Quetelet's index as prognostic indicators in women
Authors: Campbell M. J. 
Published: April 2007

AbstractI describe methods of analysing possible aetiological factors in a follow‐up survey, all of which are possible to carry out using the statistical package GENSTAT. A high haemoglobin level carried a significantly increased risk of ischaemic heart disease, and a low one an increased risk of cancer. Smoking was also an important factor. The increased risk was reasonably constant over time. Sugar intake and Quetelet's index did not significantly affect the relative risk.
Tests for interaction in epidemiologic studies: A review and a study of power
Authors: Greenland Sander 
Published: April 2007

AbstractTests for statistical interaction have come into increasing use in epidemiologic analysis, with most based on either an additive or multiplicative model for joint effects. Further procedures have been proposed for testing the goodness‐of‐fit and comparing the fit of the latter models. This paper reviews the relationships between the various tests and model comparison methods, and, for the special case of two dichotomous risk factors, presents asymptotic power functions for tests of additivity and multiplicativity. For a range of sample sizes and factor effects, the powers of the tests are computed using both the asymptotic power function and simulation studies. The powers of the tests are very low in several commonly encountered situations. In addition, convergence to the asymptotic distribution appears slow for some of the statistics. The results also indicate that likelihood comparison procedures can provide a useful adjunct to the classical hypothesis‐testing approach.
Regression modelling strategies for improved prognostic prediction
Authors: Harrell Frank E. , Lee Kerry L. , Califf Robert M. , Pryor David B. , Rosati Robert A. 
Published: April 2007

AbstractRegression models such as the Cox proportional hazards model have had increasing use in modelling and estimating the prognosis of patients with a variety of diseases. Many applications involve a large number of variables to be modelled using a relatively small patient sample. Problems of overfitting and of identifying important covariates are exacerbated in analysing prognosis because the accuracy of a model is more a function of the number of events than of the sample size.We used a general index of predictive discrimination to measure the ability of a model developed on training samples of varying sizes to predict survival in an independent test sample of patients suspected of having coronary artery disease. We compared three methods of model fitting: (1) standard ‘step‐up’ variable selection, (2) incomplete principal components regression, and (3) Cox model regression after developing clinical indices from variable clusters. We found regression using principal components to offer superior predictions in the test sample, whereas regression using indices offers easily interpretable models nearly as good as the principal components models. Standard variable selection has a number of deficiencies.
Goodness‐of‐fit based confidence intervals for estimates of the size of a closed population
Authors: Regal Ronald R. , Hook Ernest B. 
Published: April 2007

AbstractMethods for estimating the size of a closed population often consist of fitting some model (e.g. a log‐linear model) to data with a missing cell corresponding to the members of the population missed by all reporting sources. Although the use of the asymptotic standard error is the usual method for forming confidence intervals for the population total, the sample sizes are not always large enough to produce valid confidence intervals. We propose a method for forming confidence intervals based upon changes in a goodness‐of‐fit statistic associated with changes in trial values of the population total.