bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enzymatic responses of human deciduous pulpal fibroblasts to dental restorative materials
Authors: Chen Chern‐Chin , Chen Robert Cheng‐Shen , Huang Shun‐Te 
Published: August 2002

AbstractThe purpose of this study was to evaluate the responses of succinic dehydrogenase (SDH) and alkaline phosphatase (ALP) activities of human deciduous teeth pulpal fibroblasts (HDPF) to dental restorative materials. Tested materials included Z100 (3M), Dyract (Dentsply), FujiII (GC), and FujiIILC (GC). IRM (Dentsply) and culture medium (MD) alone were used as positive and negative controls, respectively. Specimens 6 mm (diameter) × 3 mm were prepared in accordance with manufacturers’ instructions. For light‐cured materials, specimens were light cured for 40 s on both sides under a celluloid strip. For chemical‐cured materials, specimens were allowed to set at room temperature for 15 min. The specimens were immersed in 1 mL of culture medium without serum for 24 h at room temperature. The extracts were filtered through 0.22‐mm filters. HDPF (10,000 cells/well) was incubated with 100 μL of extract and 20 % FBS in a 96‐well plate for 24 h in a 37°, 5 % CO2 incubator. Six wells per material were prepared. Optical density (OD) of SDH and ALP of HDPF were measured by a spectrophotometer. The means were analyzed by ANOVA and then a Duncan Test. The ranking of OD of SDH was IRM < FujiIILC < FujiII = Z100 < Dyract < MD (p < 0.05). The ranking of OD of ALP was IRM < Z100 = Dyract < FujiII < FujiIILC < MD (p < 0.05). The result showed that all of the tested restorative materials were cytotoxic to human deciduous pulpal fibroblasts. The cytotoxicity of resin‐modified glass ionomer cements (FujiIILC) was stronger than that of traditional glass ionomer cements (FujiII) and composite resin (Z100), and that of compomer (Dyract) was the weakest. On the contrary, ALP activities of resin‐modified glass ionomer cements (FujiIILC) and composite resin (Z100) were higher than those of traditional glass ionomer cements (FujiII), while those of compomer (Dyract) were the lowest. It is concluded that, in this study, FujiIILC was the most cytotoxic material and the least inhibitive of ALP activities, Dyract was the weakest cytotoxic material and had the highest inhibition of ALP activities. The rankings of the MTT assay and the ALP assay were not consistent. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 60: 452–457, 2002; DOI 10.1002/jbm.1291
ATP stimulates human placental 11β‐hydroxysteroid dehydrogenase type 2 activity by a novel mechanism independent of phosphorylation
Authors: Yang K. , Hardy D.B. , Doumouras M.A. , van Beek J.P. , Rocha E. 
Published: August 2002

AbstractThe human placental 11β‐hydroxysteroid dehydrogenase type 2 (11β‐HSD2) is believed to play a key role in fetal development since this enzyme protects the fetus from exposure to high levels of maternal cortisol by virtue of converting maternal cortisol to its inert metabolite cortisone. The present study was undertaken to examine the effect of ATP on 11β‐HSD2 activity in human placental microsomes. Enzyme activity, reflected by the rate of conversion of cortisol to cortisone, was stimulated more than six‐fold by 0.5 mM ATP (EC50 = 0.2 mM). Such stimulation appears to be mediated through a novel mechanism independent of ATP‐induced phosphorylation of the reaction components since AMP‐PNP, a non‐hydrolyzable analogue of ATP, was equally effective. The ATP‐induced stimulation of 11β‐HSD2 activity is adenine nucleotide specific in that a similar stimulation was observed with ADP and AMP but not with CTP, GTP, or UTP. Furthermore, ATP increased the maximal velocity (Vmax) of the 11β‐HSD2 catalyzed conversion of cortisol to cortisone without altering the apparent Km of 11β‐HSD2 for cortisol, suggesting that ATP may stimulate enzyme activity by interacting with the enzyme at a site other than that involved in substrate binding. In conclusion, the present study has identified ATP as a novel regulator of human placental 11β‐HSD2 in vitro. It is conceivable that intracellular ATP may have a profound effect on 11β‐HSD2 function in vivo. J. Cell. Biochem. 84: 295–300, 2002. © 2001 Wiley‐Liss, Inc.
Regulation of tumor invasion and metastasis in protein kinase C epsilon‐transformed NIH3T3 fibroblasts
Authors: Tachado Souvenir D. , Mayhew Mark W. , Wescott Ginger G. , Foreman Tonia L. , Goodwin Crystal D. , McJilton Meagan A. , Terrian David M. 
Published: August 2002

AbstractProtein kinase C epsilon is an oncogenic, actin nucleating protein that coordinately regulates changes in cell growth and shape. Cells constitutively expressing PKCϵ spontaneously acquire a polarized morphology and extend long cellular membrane protrusions. Here we report that the regulatory C1 domain of PKCϵ contains an actin binding site that is essential for the formation of elongate invadopodial‐like structures, increased pericellular metalloproteinase activity, in vitro invasion of a Matrigel barrier, and the invasion and metastasis of tumors grown in vivo by PKCϵ‐transformed NIH3T3 fibroblasts in nude mice. While removing this small actin binding motif caused a dramatic reversion of tumor invasion, the deletion mutant of PKCϵ remained oncogenic and tumorigenic in this experimental system. We propose that PKCϵ directly interacts with actin to stimulate polymerization and the extension of membrane protrusions that transformed NIH3T3 cells use in vivo to penetrate and degrade surrounding tissue boundaries. J. Cell. Biochem. 85: 785–797, 2002. © 2002 Wiley‐Liss, Inc.
Vanadate protects human neuroblastoma SH‐SY5Y cells against peroxynitrite‐induced cell death
Authors: Saeki Makio , Maeda Sadaaki , Kamisaki Yoshinori 
Published: August 2002

AbstractWe investigated the effect of vanadate, a tyrosine phosphatase inhibitor, on cell death induced by peroxynitrite in human neuroblastoma SH‐SY5Y cells. Vanadate prevented cell death induced by 3‐morpholinosydnonimine (SIN‐1), a peroxynitrite donor; whereas SIN‐1‐induced cell death was not prevented by neither okadaic acid, an inhibitor of serine/threonine phosphatases 1 and 2A, nor cyclosporin A, an inhibitor of serine/threonine phosphatase 2B. Vanadate did not prevent cell death induced by N‐ethyl‐2‐(1‐ethyl‐hydroxy‐2‐nitrosohydrazino)‐ethanamine, a nitric oxide donor. Wortmannin, an inhibitor of phosphatidylinositol 3‐kinase (PI3‐kinase), did not block the protective effect of vanadate, suggesting that the protective effect of vanadate is independent on PI3‐kinase. Vanadate increased tyrosine phosphorylation of several proteins including the focal adhesion protein p130 Crk‐associated substrate (p130cas). By the treatment with SIN‐1, the endogenous association of p130cas and Crk was disrupted, and the association was restored by vanadate treatment. These results suggest that disruption of tyrosine phosphorylation signaling may be critical for peroxynitrite‐induced cell death, and that vanadate prevents cell death at least in part through the enhancement in tyrosine phosphorylation of the proteins including p130cas. J. Cell. Biochem. 85: 721–727, 2002. © 2002 Wiley‐Liss, Inc.
Chromatin of Trypanosoma cruzi: In situ analysis revealed its unusual structure and nuclear organization
Authors: Spadiliero Barbara , Nicolini Claudio , Mascetti Giancarlo , Henríquez Diana , Vergani Laura 
Published: August 2002

AbstractChromatin of Trypanosoma cruzi is known to be organized in classical nucleosomal filaments, but surprisingly, these filaments do not fold in visible chromosomes and the nuclear envelope is preserved during cell division. Our hypothesis about the role of chromatin structure in regulating gene expression and, more generally, cell functioning, pressed us to verify if chromatin organization is modulated during the parasite life‐cycle. To this end, we analyzed in situ the fine structural organization of T. cruzi chromatin by means of an integrated biophysical approach, using differential scanning calorimetry and fluorescence microscopy. We observed that logarithmic forms exhibit a less condensed chromatin with respect to the stationary ones. Thermal analysis revealed that parasite chromatin is organized in three main levels of condensation, barring from the polynucleosomal filament till to superstructured fibers. Besides, the fluorescence images of nuclei showed a characteristic chromatin distribution, with defined domains localized near to the nuclear envelope. While in stationary parasites, these regions are highly condensed, in logarithmic forms they unfold by extending themselves toward the center of nucleus. These observations suggest that, in comparison with higher eukaryotes, in T. cruzi the nuclear envelope plays an unusual and pivotal role in interphase and in mitosis. J. Cell. Biochem. 85: 798–808, 2002. © 2002 Wiley‐Liss, Inc.
Structural and functional studies on Troponin I and Troponin C interactions
Authors: Ngai Sai‐Ming , Hodges Robert S. 
Published: August 2002

AbstractTroponin I (TnI) peptides (TnI inhibitory peptide residues 104–115, Ip; TnI regulatory peptide resides 1–30, TnI1–30), recombinant Troponin C (TnC) and Troponin I mutants were used to study the structural and functional relationship between TnI and TnC. Our results reveal that an intact central D/E helix in TnC is required to maintain the ability of TnC to release the TnI inhibition of the acto‐S1‐TM ATPase activity. Ca2+‐titration of the TnC‐TnI1–30 complex was monitored by circular dichroism. The results show that binding of TnI1–30 to TnC caused a three‐folded increase in Ca2+ affinity in the high affinity sites (III and IV) of TnC. Gel electrophoresis and high performance liquid chromatography (HPLC) studies demonstrate that the sequences of the N‐ and C‐terminal regions of TnI interact in an anti‐parellel fashion with the corresponding N‐ and C‐domain of TnC. Our results also indicate that the N‐ and C‐terminal domains of TnI which flank the TnI inhibitory region (residues 104 to 115) play a vital role in modulating the Ca2+‐ sensitive release of the TnI inhibitory region by TnC within the muscle filament. A modified schematic diagram of the TnC/TnI interaction is proposed. © 2001 Wiley‐Liss, Inc.
Transcriptional activation of rat creatine kinase B by 17β‐estradiol in MCF‐7 cells involves an estrogen responsive element and GC‐rich sites
Authors: Wang Fan , Samudio Ismael , Safe Stephen 
Published: August 2002

AbstractThe rat creatine kinase B (CKB) gene is induced by estrogen in the uterus, and constructs containing rat CKB gene promoter inserts are highly estrogen‐responsive in cell culture. Analysis of the upstream −568 to −523 region of the promoter in HeLa cells has identified an imperfect palindromic estrogen response element (ERE) that is required for hormone inducibility. Analysis of the CKB gene promoter in MCF‐7 breast cancer cells confirmed that pCKB7 (containing the −568 to −523 promoter insert) was estrogen‐responsive in transient transfection studies. However, mutation and deletion analysis of this region of the promoter showed that two GC‐rich sites and the concensus ERE were functional cis‐elements that bound estrogen receptor α (ERα)/Sp1 and ERα proteins, respectively. The role of these elements was confirmed in gel mobility shift and chromatin immunoprecipitation assays and transfection studies in MDA‐MB‐231 and Schneider Drosophila SL‐2 cells. These results show that transcriptional activation of CKB by estrogen is dependent, in part, on ERα/Sp1 action which is cell context‐dependent. J. Cell. Biochem. 84: 156–172, 2002. © 2001 Wiley‐Liss, Inc.
Transition state docking: A probe for noncovalent catalysis in biological systems. Application to antibody‐catalyzed ester hydrolysis
Authors: Tantillo Dean J. , Houk K. N. 
Published: August 2002

AbstractA strategy for pinpointing favorable noncovalent interactions between transition states and active sites of biological catalysts is described. This strategy combines high‐level quantum mechanical calculations of transition state geometries with an automated docking procedure using AutoDock. By applying this methodology to antibody‐catalyzed hydrolyses of aryl esters (by the 48G7, CNJ206, and 17E8 families of antibodies), varying levels of catalysis are explained in terms of specific hydrogen bonding interactions between combining site residues and transition states. Although these families of antibodies were produced in separate experiments by different researchers using related but different haptens, the mechanism of transition state stabilization appears to be highly conserved. Despite being elicited in response to anionic phosphonate haptens, the best catalysts often utilize hydrogen bond acceptors to stabilize transition states. A mutant of antibody CNJ206, designed based on this observation and predicted to be a better catalyst, is proposed. In the case of antibody 48G7, affinity maturation is shown to produce a catalyst that is highly selective for one of two enantiomeric transition states from a nonselective germline precursor. © 2002 Wiley Periodicals, Inc. J Comput Chem 23: 84–95, 2002
Calculation of X‐ray scattering intensities by means of the coupled cluster singles and doubles model
Authors: Watanabe Noboru , Kamata Yohei , Yamauchi Kota , Udagawa Yasuo 
Published: August 2002

AbstractTotal X‐ray scattering intensity σee(q) is very sensitive to electron correlation effects. In this study σee(q) of N2, CO, and N2O have been computed by the coupled cluster singles and doubles (CCSD) method and compared with configuration interaction singles and doubles (CISD) calculations as well as experimental observations. σee(q) curves by CCSD calculations are rather close to those by CISD, but although small, there still exist some discrepancies between calculated and observed values. © 2001 John Wiley & Sons, Inc. J Comput Chem 22: 1315–1320, 2001
Bounds on affine caps
Authors: Bierbrauer Jürgen , Edel Yves 
Published: August 2002

AbstractWe present a short and elementary proof for an upper bound on caps in affine spaces. The bound generalizes and strengthens a result by Meshulam. The proof is inspired by Meshulam's Fourier transform method without making explicit use of the Fourier transform. © 2002 Wiley Periodicals, Inc. J Combin Designs 10: 111–115, 2002; DOI 10.1002/jcd.10000
Phosphorylation of focal adhesion kinase (pp125FAK) is increased in human keratinocytes induced to migrate by extracellular matrices
Authors: Yurko Mary A. , O'Toole Edel A. , Woodley David T. 
Published: August 2002

AbstractDuring the healing process of skin wounds, human keratinocytes migrate across a provisional matrix of the wound bed. The mechanisms by which keratinocytes migrate on connective tissue are not known. In this study, we examined the role of focal adhesion kinase (FAK), an 125 kDa protein that co‐localizes with focal adhesions in cells plated on extracellular matrix. We induced human keratinocytes into various states of migration by plating them on extracellular matrices that minimally, moderately, or strongly induce cellular migration, and then examined the expression of FAK at the protein level and its degree of tyrosine phosphorylation using Western immunoblotting and immunoprecipitation. In highly migratory human keratinocytes, we found that three proteins were predominantly tyrosine phosphorylated, one of them being FAK. Tyrosine phosphorylation of FAK tightly correlated with the level of cellular motility but not cell attachment to the matrix. Time course experiments demonstrated that in highly motile keratinocytes, tyrosine phosphorylation of FAK peaked at 12 h, the time when maximal migration on the matrix ensues. In contrast to FAK, the β1 integrin subunit of human keratinocytes that configures with the α2, α3, and α5 integrin subunits to form integrin receptors for matrix, did not display tyrosine phosphorylation linked to motility. Using anti‐sense oligonucleotides to FAK, we demonstrate that FAK is required for human keratinocyte migration, but not for focal adhesion formation. © 2001 Wiley‐Liss, Inc.
Effect of extraction and enzymatic esterification of ethanol on glucose consumption by two Saccharomyces cerevisiae strains: a comparative study
Authors: Oliveira A Cristina , Rosa M Fernanda , Cabral Joaquim M S , Aires‐Barros M Raquel 
Published: August 2002

AbstractExtractive alcoholic fermentations of high glucose concentrations (300 and 400 g dm−3) using a flocculent (saké) and a non‐flocculent (DER24) Saccharomyces cerevisiae strain were compared. The introduction of a Rhizomucor miehei lipase, in the extractive fermentations of 300 g dm−3 of glucose, increased the ethanol extraction due to its esterification with oleic acid, allowing complete glucose consumption at an organic solvent/fermentation medium phase ratio of 1. In these conditions, an increase of ethanol yield was observed. Total glucose consumption was also obtained in enzymatic extractive fermentations of 400 g dm−3 of glucose, but only when oleic acid was added at the exponential growth phase. From the comparison of the extractive fermentation performances obtained using the two yeast strains it was observed that the flocculent strain led to a lower glucose metabolisation rate. This behaviour was related to the highest diffusional limitations that occur in the presence of flocs. The developed processes showed that the association of alcoholic fermentation with enzymatic extraction led to the reduction of inhibitory effects as well as to the simultaneous production of fatty esters which are compounds with several commercial applications.© 2001 Society of Chemical Industry
Dimethylsulfoxide elevates extracellular laccase (phenol oxidase) activity ofPycnoporus cinnabarinusgrown on a low nutritional newspaper medium
Authors: Jones Cameron L , Baker Warren L , Lonergan Greg T 
Published: August 2002

AbstractThe white‐rot fungusPycnoporus cinnabarinus, grown on a low nutrient newspaper medium, secreted low amounts of extracellular laccase. The laccase activity was increased when 3% methanol was added to the medium and further increased when 3% dimethylsulfoxide was added. Dimethylsulfoxide increased the enzyme activity over controls when the fungus was grown on a malt extract broth, or media containing either recycled Kraft paper or cellobiose. Treatment with the ionophore A23187 suggested that dimethylsulfoxide acted as a paramorphogen to increase the branch points of the mycelial mat. Hence, the number of ion channels for secretion of the enzyme was increased. When the fungus was grown in a 2 dm3bioreactor, sparged with air, the measured extracellular protein concentration rose and remained relatively steady for 15 days. The enzyme activity and specific activity reached a maximum between days 6 and 9 and then fell from day 10 of fermentation. The presence of dimethylsulfoxide in the bioreactor caused a four‐fold increase in enzyme activity and prolonged its secretion in the bioreactor for at least 25 days. The protein concentration and specific activity also remained at high levels over this period.© 2001 Society of Chemical Industry
Enzymatic alcoholysis of triolein to produce wax ester
Authors: Hadzir Nursyamsyila Mat , Basri Mahiran , Rahman Mohd Basyaruddin Abd , Razak Che Nyonya Abdul , Rahman Raja Noor Zaliha Abd , Salleh Abu Bakar 
Published: August 2002

AbstractAn alcoholysis reaction between triolein and oleyl alcohol catalyzed by Lipozyme and Novozyme was carried out to produce oleyl oleate, a wax ester. The effects of various reaction parameters such as time, reaction temperature, amount of enzyme, molar ratio of substrates (oleyl alcohol/triolein), various organic solvents used and the initial water activity, aw of the reaction system were studied. The best conditions tested to produce wax ester were respectively, incubation time, 5 h; temperature, 50 °C for Lipozyme and 60 °C for Novozyme; weight of enzyme, 0.30 g and molar ratio of oleyl alcohol to triolein, 6:1. The use of organic solvents greatly influenced the activity of lipase. Generally, the activity of lipase was high in nonpolar solvents with log P values greater than 2.50. Heptane and hexane were the best solvents tested. The enzymatic synthesis of oleyl oleate was best carried out at aw 0.32. Analysis of the yield of the products of the reaction at optimized reaction condition using Lipozyme showed that 75.66% oleyl oleate was produced.© 2001 Society of Chemical Industry
Two small intrahepatic cholangiocarcinomas with different sonographic appearances
Authors: Yamamoto Takatsugu , Takeuchi Kazuo , Okuda Chikao , Honjo Hajime , Sakurai Norio , Watanabe Goro , Mori Masaya , Kuyama Yasushi 
Published: August 2002

AbstractWe report on 2 cases of small intrahepatic (or peripheral) cholangiocarcinomas initially detected by sonography and completely resected. The lesions had a peripheral hypoechoic component and a central isoechoic or hyperechoic component. One had posterior acoustic shadowing on sonography, and the other did not. Comparison with pathologic findings in both cases indicated that severe fibrotic changes may have caused the posterior acoustic shadowing. This finding is extremely rare. We found only 1 previously reported case of cholangiocarcinoma accompanied by acoustic shadowing. © 2001 John Wiley & Sons, Inc. J Clin Ultrasound 29:344–348, 2001.
Transporters in the neurohypophysial neuroendocrine system, with special reference to vesicular glutamate transporters (BNPI and DNPI): A review
Authors: Hisano Setsuji , Nogami Haruo 
Published: August 2002

AbstractRecent advances in gene technology have helped to identify novel proteins and allowed study of their distribution and functions in the mammalian brain. One class of these proteins is that of transporters, which exist in plasma and organellar membranes of neurons and other cells to move substances selectively across membranes. These transporters can be categorized further into subclasses by their structural property, substrate selectivity, and site of action. Some of them have been identified in the hypothalamus, which is the only brain site where a neural signal is converted to a humoral one, namely, a hormone for a target organ. This unique neural mechanism has long attracted attention as the neuroendocrine system, part of which has been extensively studied as the hypothalamic‐neurohypophysial system involved in secretion of vasopressin and oxytocin. However, transporters in this system have been less well studied. A morphological examination of novel transporters would give us cues to a better understanding of the neuronal organization and function of the system. In this review, we first summarize recent findings on expression of transporter gene and immunoreactivity in the hypothalamus. In the second part, we explain our observations on two vesicular glutamate (inorganic phosphate) transporters (BNPI and DNPI) in the supraoptic and paraventricular nuclei and neurohypophysis. Further study of these and other transporters will provide a basis on which to reevaluate the organization and function of the hypothalamic‐neurohypophysial system. Microsc. Res. Tech. 56:122–131, 2002. © 2002 Wiley‐Liss, Inc.