bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Silver Nanoparticles on the Electron Transfer Reactivity and the Catalytic Activity of Myoglobin
Authors: Gan Xin , Liu Tao , Zhong Jun , Liu Xinjian , Li Genxi
Published: November 2004

Silver nanoparticles (11±1.5 nm) could greatly enhance the electron‐transfer reactivity of myoglobin (Mb) and its catalytic ability toward hydrogen peroxide (H2O2). Direct fast electron transfer between Mb and a pyrolytic graphite (PG) electrode was achieved, and a pair of well‐defined, quasireversible redox peaks was obtained. The cathodic and anodic peaks were located at −329 and −281 mV, respectively. Meanwhile, the catalytic ability of the protein toward the reduction of H2O2 was also studied, and a H2O2 biosensor was subsequently fabricated. Its detection limit was 1.0×10−6 M with a sensitivity of 0.0205 μA per μM of H2O2. The apparent Michaelis–Menten constant was calculated to be 1303 μM. Flocculation assay showed that the protein maintained plasmon layers surrounding the surface of silver nanoparticles and avoided silver‐nanoparticle aggregation. On the other hand, UV‐visible spectroscopy studies revealed that silver nanoparticles could induce a small change of the heme‐group environment of the protein; this contributed to the enhancement of the electron‐transfer reactivity and the catalytic activity.
Peroxidase Activity of Cationic Metalloporphyrin‐Antibody Complexes
Authors: Yamaguchi Hiroyasu , Tsubouchi Kaori , Kawaguchi Kazuhide , Horita Eri , Harada Akira
Published: November 2004

Peroxidase activity of a complex of water‐soluble cationic metalloporphyrin with anti‐cationic porphyrin antibody is reported. Antibody 12E11G, which was prepared by immunization with a conjugate of 5‐(4‐carboxyphenyl)‐10,15,20‐tris(4‐methylpyridyl)porphine iodide (3MPy1C), bound to tetramethylpyridylporphyrin iron complex (FeIII–TMPyP) with the dissociation constant of 2.6×10−7 M. The complex of antibody 12E11G with FeIII–TMPyP catalyzed oxidation of pyrogallol, catechol, and guaiacol. A Lineweaver–Burk plot for the oxidation of pyrogallol catalyzed by the FeIII–TMPyP–antibody complex showed Km=8.6 mM and kcat=680 min−1. Under the same conditions, Km and kcat for horseradish peroxidase (HRP) were 0.8 mM and 1750 min−1, respectively. Although the binding interaction of the antibody to the substrates was one order lower than that of native HRP, the peroxidase activity of this system was in the same order of magnitude as that of HRP.
Intramolecular γ‐Hydroxylations of Nonactivated CH Bonds with Copper Complexes and Molecular Oxygen
Authors: Schönecker Bruno , Zheldakova Tatjana , Lange Corinna , Günther Wolfgang , Görls Helmar , Bohl Martin
Published: November 2004

Copper(I) complexes incorporating the isomeric bidentate ligands IMPY (iminomethyl‐2‐pyridines) or AMPY (aminomethylene‐2‐pyridines) are quite unusual in their ability to bind and activate molecular oxygen. Using these complexes, hydroxylations of nonactivated CH, CH2, or CH3 groups in the γ‐position in relation to the imino‐nitrogen atom, and with a specific orientation of one H atom with respect to the binuclear CuO species, can be achieved in synthetically useful yields. Through mechanistic studies employing conformationally well‐defined molecules (for example, cyclic isoprenoids), coupled with solid‐state X‐ray structure analyses and force‐field calculations, we postulate a seven‐membered transition state for this reaction in which six atoms lie approximately in a plane. This plane is defined by the positions of the lone pairs on the nitrogen atoms, as well as the copper and the oxygen atoms. For a successful hydroxylation, one hydrogen atom should be located close to this plane. Prediction of the stereochemical course of these reactions is possible based on a simple geometrical criterion. The convenient introduction of IMPY and AMPY groups as auxiliaries into oxo and primary amino compounds and the simple hydrolysis after the hydroxylation procedure has allowed the synthesis of 3‐hydroxy‐1‐oxo and 3‐hydroxy‐1‐amino compounds. If desired, the 3‐hydroxy‐1‐IMPY and ‐1‐AMPY compounds can be reduced with NaBH4 to obtain 3‐hydroxy‐1‐aminomethylpyridines. For a successful hydroxylation procedure, the method employed for the synthesis of the CuI complexes is very important. Starting either from CuI salts or from CuII salts with a subsequent reduction with benzoin/triethylamine may turn out to be the better way, depending on the ligand and the molecular structure.
Bulky Monodentate Phosphoramidites in Palladium‐Catalyzed Allylic Alkylation Reactions: Aspects of Regioselectivity and Enantioselectivity
Authors: Boele Maarten D. K. , Kamer Paul C. J. , Lutz Martin , Spek Anthony L. , de Vries Johannes G. , van Leeuwen Piet W. N. M. , van Strijdonck Gino P. F.
Published: November 2004

A series of bulky monodentate phosphoramidite ligands, based on biphenol, BINOL and TADDOL backbones, have been employed in the Pd‐catalysed allylic alkylation reaction. Reaction of disodium diethyl 2‐methyl malonate with monosubstituted allylic substrates in the presence of palladium complexes of the phosphoramidite ligands proceeds smoothly at room temperature. The regioselectivities observed depend strongly on the leaving group and the geometry of the allylic starting compounds. Mono‐coordination occurs when these ligands are ligated in [Pd(allyl)(X)] complexes (allyl=C3H5, 1‐CH3C3H4, 1‐C6H5C3H4, 1,3‐(C6H5)2C3H3; X=Cl, OAc). The solid‐state structure determined by X‐ray diffraction of [Pd(C3H5)(1)(Cl)] reveals a non‐symmetric coordination of the allyl moiety, caused by the stronger trans influence of the phosphoramidite ligand relative to X−. In all of these complexes, the syn,trans isomer is the major species present in solution. Because of fast isomerisation and high reactivity of the syn,cis complex, the major product formed upon alkylation is the linear product, especially for monosubstituted phenylallyl substrates in the presence of halide counterions. In the case of biphenol‐ and BINOL‐based phosphoramidites, however, a strong memory effect is observed when 1‐phenyl‐2‐propenyl acetate is employed as the substrate. In this case, nucleophilic attack competes effectively with the isomerisation of the transient cinnamylpalladium complexes. The asymmetric allylic alkylation of 1,3‐diphenyl‐2‐propenyl acetate afforded the chiral product in up to 93 % ee. Substrates with smaller substituents gave lower enantioselectivities. The observed stereoselectivity is explained in terms of a preferential rotation mechanism, in which the product is formed by attack on one of the isomers of the intermediate [Pd{1,3‐(C6H5)2C3H3}(L)(OAc)] complex.
Colorectal carcinoma mortality among Appalachian men and women, 1969–1999
Authors: Armstrong Lori R. , Thompson Trevor , Hall H. Irene , Coughlin Steven S. , Steele Brooke , Rogers Joe D.
Published: November 2004

BACKGROUND

Colorectal carcinoma screening can reduce mortality, but residents of poor or medically underserved areas may face barriers to screening. The current study assessed colorectal carcinoma mortality in Appalachia, a historically underserved area, from 1969 to 1999.

METHODS

All counties within the 13‐state Appalachian region, which stretches from southern New York to northern Mississippi, were used to calculate annual death rates for the 31‐year period. Joinpoint regression analysis was used to examine trends by age and race for the Appalachian region and the remainder of the United States. Five‐year rates for 1995–1999 age‐adjusted to the 2000 U.S. standard population were calculated by race and age group for the Appalachian region and elsewhere in the United States.

RESULTS

Trend analysis showed that colorectal carcinoma death rates among both racial and gender groups studied had declined in recent years. Despite this, the rates for white males and white females were still significantly higher in Appalachia than in the rest of the country at the end of the study period, 1999. Five‐year colorectal carcinoma death rates among white males (ages < 50, 50–59, and 70–79 years) and white females (ages < 50, 50–59, 70–79, ≥ 80 years) were significantly higher in Appalachia than elsewhere in the United States, whereas rates among black females 60–69 and 70–79 years old were significantly lower in Appalachia.

CONCLUSIONS

The Appalachian region may benefit from targeted prevention efforts to eliminate disparities in the colorectal carcinoma death rates among subgroups. Further studies are needed to determine whether the higher death rates in specific Appalachian subgroups are related to a higher incidence of the disease, the cancer being at a later stage at diagnosis, poorer treatment, or other factors. Cancer 2004. Published 2004 by the American Cancer Society.
Local and global chemotopic organization: General features of the glomerular representations of aliphatic odorants differing in carbon number
Authors: Johnson Brett A. , Farahbod Haleh , Xu Zhe , Saber Sepideh , Leon Michael
Published: November 2004

To determine whether there is a general strategy used by the olfactory system to represent odorants differing in carbon chain length, rats were exposed to homologous series of straight‐chained, saturated aliphatic aldehydes, ethyl esters, acetates, ketones, primary alcohols, and secondary alcohols (32 odorants total). Neural activity across the entire glomerular layer of the olfactory bulb was mapped quantitatively by measuring uptake of [14C]2‐deoxyglucose evoked by each odorant. Uptake was observed both in dorsal glomerular modules previously associated with the particular odorant functional groups and in more ventral and posterior modules. Aldehyde‐evoked activity patterns were dominated by ventral modules that included the area receiving projections from octanal‐responsive sensory neurons expressing the I7 odorant receptor. The dorsal area that has been the focus of optical imaging studies of aldehyde responses contained only minor activity. For all functional groups except for ketones, uptake within functional group‐sensitive modules displayed local chemotopy, with longer odorants stimulating more ventral and rostral glomeruli. In more posterior regions, chemotopy was observed for all functional groups, again with uptake shifting ventrally and rostrally with increasing chain length. In addition to these local shifts in activity, correlations analysis of entire activity patterns revealed a global chemotopic organization for all odorant series, with each odorant evoking a pattern most similar to odorants possessing the same functional group but differing by only one carbon in length. Thus, global chemotopy and local modular chemotopy appear to be fundamental principles underlying the representation of odorants differing in carbon chain length. J. Comp. Neurol. 480:234–249, 2004. © 2004 Wiley‐Liss, Inc.
Experimental study of the connections of the telencephalon in the rainbow trout (Oncorhynchus mykiss). II: Dorsal area and preoptic region
Authors: Folgueira Mónica , Anadón Ramón , Yáñez Julián
Published: November 2004

In this study and the accompanying article (Folgueira et al., 2004a), the fluorescent carbocyanine dye 1,1′‐dioctadecyl 3,3,3′,3′‐tetramethylindocarbocyanine perchlorate (DiI) was used in fixed tissue to comprehensively analyze the connections of the different regions of the telencephalic lobes and the preoptic region of the rainbow trout. Here, we analyze the connections of the dorsal area (D; pallium) of the telencephalon, and the preoptic region, as well as the telencephalic connections of several structures in the diencephalon and brainstem of juvenile trout. The dorsal plus dorsolateral pallial zone of D (Dd+Dl‐d) receives afferents from contralateral Dd+Dl‐d, the ventral area of the telencephalon, preoptic nucleus, suprachiasmatic nucleus, medial thalamus, preglomerular complex, anterior and lateral tuberal nuclei, posterior tuberal nucleus, posterior hypothalamic lobe, superior raphe nucleus, and the rhombencephalic central gray and reticular formation, and projects to the central zone of D (Dc), medial thalamus, and some caudomedial hypothalamic regions. The medial zone of D (Dm) maintains reciprocal connections with the preglomerular complex and also receives afferents from the preoptic nucleus, suprachiasmatic nucleus, anterior tuberal nucleus, preglomerular tertiary gustatory nucleus, posterior tubercle, superior raphe nucleus, locus coeruleus, and the rhombencephalic central gray, and reticular formation. Dc receives fibers mainly from Dd+Dl‐d, preoptic nucleus, preglomerular complex, and torus semicircularis and projects to several extratelencephalic centers, including the paracommissural nucleus, optic tectum, torus semicircularis, thalamus, preglomerular complex, posterior tubercle nuclei, and inferior hypothalamic lobes. The posterior zone of D (Dp) is mainly connected with the olfactory bulbs, the ventral and supracommissural nuclei of the ventral area (subpallium), the preoptic nucleus, and the preglomerular complex and projects to wide hypothalamic and posterior tubercular regions. The preoptic nucleus projects to the olfactory bulb, to most regions of the telencephalic lobes, and to several diencephalic and brainstem structures. These results reveal complex and specialized connectional patterns in the rainbow trout dorsal telencephalon and preoptic region. Most of these connections have not been described previously in salmonids. These connections indicate that the salmonid telencephalon is involved in multisensorial processing and modulation of brain activity. J. Comp. Neurol. 480:204–233, 2004. © 2004 Wiley‐Liss, Inc.
Urocortinergic neurons respond in a differentiated manner to various acute stressors in the Edinger‐Westphal nucleus in the rat
Authors: Gaszner Balázs , Csernus Valér , Kozicz Tamás
Published: November 2004

Corticotropin‐releasing factor (CRF) was implicated as being a major contributor to the neurochemically mediated central regulation of stress response; however, an increasing body of evidence suggests that, besides CRF, other members of this neuropeptide family, such as urocortin (Ucn), may also play a role in modifying the efferent components of immune, endocrine, and behavioral responses to stress. Ucn's distribution in the rat brain has been demonstrated, with the most abundant Ucn‐immunoreactive perikarya present in the Edinger‐Westphal nucleus (E‐WN). Acute pain and immobilization stresses recruit E‐WN neurons, however, the activation pattern of E‐WN Ucn neurons in response to various acute systemic and neurogenic challenges has not been compared in a single study. We therefore combined quantitative Fos imaging as a marker for neuronal activation with urocortin immunohistochemistry to visualize neurons induced by intravenous lipopolysaccharide (LPS; 100 μg/kg), ether inhalation, restraint, hyperosmotic (1.5 M NaCl i.p.), and hypotensive hemorrhage challenges. Neurons in the E‐WN responded with the strongest Fos induction to LPS, but ether and restraint stress also resulted in massive Fos immunoreactivity 2 hours after stress. Unexpectedly, hyperosmotic and hypotensive hemorrhage stresses did not induce urocortinergic perikarya in this brain area 2 hours poststress. This challenge‐specific recruitment of E‐WN neurons was independent of stress‐induced adrenal response. The biological significance and the stress‐specific activation of E‐WN urocortinergic neurons will be discussed. J. Comp. Neurol. 480:170–179, 2004. © 2004 Wiley‐Liss, Inc.
Dispersive analysis of charge transfer models
Authors: Rodnianski I. , Schlag W. , Soffer A.
Published: November 2004

We prove dispersive estimates for the time‐dependent Schrödinger equation with a charge transfer Hamiltonian. As a by‐product we also obtain another proof of asymptotic completeness of the wave operators for a charge transfer model established earlier by K. Yajima and J. M. Graf. We also consider a more general matrix non‐self‐adjoint charge transfer problem. This model appears naturally in the study of nonlinear multisoliton systems and is specifically motivated by the problem of asymptotic stability of multisoliton states of a nonlinear Schrödinger equation. © 2004 Wiley Periodicals, Inc.
Directing pluripotent cell differentiation using “diced RNA” in transient transfection
Authors: Carpenter Lee , Zernicka‐Goetz Magdalena
Published: November 2004

Embryonic stem (ES) and embryonic carcinoma (EC) cells are pluripotent and have the capacity to differentiate into many cell types. The ability to direct their differentiation should have considerable practical applications. Here, we first report the use of diced short interfering RNAi against Oct4 in a transient approach, to direct differentiation of ES towards the trophectoderm lineage. We then apply this approach to downregulate Smad4 in mouse P19 EC cells. We have found that this leads to an increase in the levels of Pax6 (a neuroectoderm marker), reduction in the levels of Brachyury (a mesoderm marker), and a 3‐fold increase in the number of βIII tubulin‐positive colonies when these cells were allowed to differentiate. This indicates a redirection of cell fate towards the neuroectoderm lineage. Thus, transient RNAi could provide a valuable tool to direct pluripotent cells along specific pathways of differentiation while circumventing permanent genetic changes. genesis 40:157–163, 2004. © 2004 Wiley‐Liss, Inc.
Positional cloning and characterization of mouse mei8, a disrupted allele of the meiotic cohesin Rec8
Authors: Bannister Laura A. , Reinholdt Laura G. , Munroe Robert J. , Schimenti John C.
Published: November 2004

A novel mutation, mei8, was isolated in a forward genetic screen for infertility mutations induced by chemical mutagenesis of ES cells. Homozygous mutant mice are sterile. Mutant females exhibit ovarian dysgenesis and lack ovarian follicles at reproductive maturity. Affected males have small testes due to arrest of spermatogenesis during meiotic prophase I. Genetic mapping and positional cloning of mei8 led to the identification of a mutation in Rec8, a homolog of the yeast meiosis‐specific cohesin gene REC8. Analysis of meiosis in Rec8mei8/Rec8mei8 spermatocytes showed that, while initiation of recombination and synapsis occurs, REC8 is required for the completion and/or maintenance of synapsis, cohesion of sister chromatids, and the formation of chiasmata, as it is in other organisms. However, unlike yeast and Caenorhabditis elegans, localization of REC8 on meiotic chromosomes is not required for the assembly of axial elements. genesis 40:184–194, 2004. © 2004 Wiley‐Liss, Inc.
A convenient route to pyridones, pyrazolo[2,3‐a]pyrimidines and pyrazolo[5,1‐c]triazines incorporating antipyrine moiety
Authors: Farag Ahmad M. , Dawood Kamal M. , Elmenoufy Hanan A.
Published: November 2004

Condensation of 4‐aminoantipyrine with ethyl acetoacetate, ethyl benzoylacetate, and ethyl cyanoacetate furnished the corresponding ethyl 3‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)aminoacrylate and 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide derivatives. The aminoacrylates derivatives react with acetonitrile and sodium hydride to give 2‐amino‐6‐methyl‐1‐(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)‐4‐pyridone. Reaction of the cyanoacetamide derivative with dimethylformamide‐dimethylacetal (DMF‐DMA) afforded 2‐cyano‐N‐[1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐pyrazol‐4‐yl]‐2‐(N,N‐dimethylamino)methylene acetamide in high yield. Treatment of the latter with 5‐aminopyrazole derivatives afforded the corresponding pyrazolo[2,3‐a]pyrimidines. 2‐cyano‐N‐[(1,2‐dihydro‐1,5‐dimethyl‐2‐phenyl‐3‐oxo‐3H‐pyrazol‐4‐yl)]acetamide also reacts with heterocyclic diazonium salts to give the corresponding pyrazolo[5,1‐c]‐1,2,4‐triazine derivatives. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:508–514, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20046
A new approach to synthesis of 3,3‐dialkyl‐3,4‐dihydroisoquinoline derivatives
Authors: Shklyaev Yu. V. , Yeltsov M. A. , Rozhkova Yu. S. , Tolstikov A. G. , Dembitsky V. M.
Published: November 2004

The synthesis of 3,3‐dialkyl‐3,4‐dihydroisoquinolines via heterocyclization in three‐component reaction of an activated arene with isobutyraldehyde and nitriles is described. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:486–493, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20049
Michael adducts‐synthons for pyrazolidinediones, isoxazolidinediones, pyrimidinetriones, and thioxopyrimidinediones
Authors: Padmavathi V. , Subbaiah D. R. C. Venkata , Sarma M. Rajagopala , Balaiah A.
Published: November 2004

4‐Substituted pyrazolidinediones, isoxazolidinediones, and 5‐substituted pyrimidinetriones, thioxopyrimidinediones were obtained by exploiting gem‐diester functionality in mono‐ and di‐substituted dimethyl malonates. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:477–481, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20053
Crystal structures and molecular modeling of 1,8 chalcogenide‐substituted naphthalenes
Authors: Aucott Stephen M. , Milton Heather L. , Robertson Stuart D. , Slawin Alexandra M. Z. , Woollins J. Derek
Published: November 2004

The molecular structures of naphtho[1,8‐cd][1,2]dithiole, naphtho[1,8‐cd][1,2]diselenole, naphtho[1,8‐cd][1,2]ditellurole, naphtho[1,8‐cd]‐ [1,2]dithiole 1‐oxide, naphtho[1,8‐cd][1,2]dithiole 1,1‐dioxide, and naphtho[1,8‐cd][1,2]dithiole 1,1,2‐trioxideand naphtho[1,8‐cd][1,2]dithiole 1,1,2,2‐tetroxide are compared. The E–E distance varies, broadly reflecting the degree of distortion imposed by the rigid naphthalene backbone as well as the degree of oxidation at sulfur.

Index Entry:
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The naphthalene backbone imposes shortening of E–E bond lengths when E = S and Se compared to PhEEPh systems but is itself subject to distortion as a consequence of the steric bulk of the E atoms. © 2004 Wiley Periodicals, Inc. Heteroatom Chem 15:530–542, 2004; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/hc.20055
Repeated in vivo electrochemical activation and the biological effects of microelectromechanical systems drug delivery device
Authors: Shawgo Rebecca S. , Voskerician Gabriela , Duc Hong Linh Ho , Li Yawen , Lynn Aaron , MacEwan Matthew , Langer Robert , Anderson James M. , Cima Michael J.
Published: November 2004

The repeated activation of a microelectromechanical systems (MEMS) drug delivery device was studied in vivo in rats to examine the effect of implantation on the device operation and the effect of electrochemical activation on the inflammatory and wound‐healing response. The MEMS devices were fabricated from a silicon wafer into which reservoirs were etched and covered with gold membranes. The membranes were electrochemically removed when an anodic voltage was applied. Devices were implanted subcutaneously both with and without stainless steel mesh cages for 4, 7, 14, 21, or 28 days before activation. Devices were activated every other day for five activations. Leukocyte concentrations indicated that both the application of voltage and the gold corrosion products elevated the inflammatory response which was resolved within 48 h after each activation. The efficiency of gold membrane removal was not impaired throughout the implantation, although a bimodal distribution of background current densities was observed after long implantation times. The thickness of the fibrous capsule surrounding the MEMS devices was similar between activated and control devices explanted at each time point. It was concluded that the repeated activation of MEMS drug delivery devices was successful and the activation produced an acceptable biological response that resolved promptly. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res 71A: 559–568, 2004
Structure formation in injectable poly(lactide‐co‐glycolide) depots. II. Nature of the gel
Authors: Wang Liwei , Venkatraman Subbu , Gan Leong Huat , Kleiner Lothar
Published: November 2004

The benzyl benzoate solutions of poly(D,L‐lactide‐co‐glycolide), a random oriented synthesized copolymer with L/G ratio of 50:50, have been shown to form gels during aging and upon injection into buffer or water. The gelation properties influence drug release kinetics for these injectable, depot‐forming solutions. In this article, we report on the mechanism of gelation. We find that only polymers that have a certain average block length of glycolide units form gels during aging as well as depots upon in vitro. Thus, gel formation is likely due to the formation of ordered solvated aggregates of blocky glycolide units. Rheometry, differential scanning calorimetry, and nuclear magnetic resonance were used to investigate the gelation kinetics and the polymer molecular parameters. Of all the polymers used, poly(lactide‐co‐glycolide)s with glycolide average block length <2.9 did not show any gelation behavior. The details of the gelation process are also solvent dependent. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 215–222, 2005
Use of the fertilized hen's egg in the evaluation of embryotoxicity of dental alloys
Authors: Durmus Ercan , Inan Özgür , Çelik Ilhami , Sur Emrah , Özkan Yasemin , Acar Asli , Aydin Mehmet Faruk
Published: November 2004

In this study, embryotoxic effects of five commercially available dental alloys were investigated by using fertilized hens' eggs. One sample of each alloy was conditioned in one of the conditioning media, physiological saline (PS), 0.1 M phosphate‐buffered saline (PBS, pH 7.4), and 0.1 M protein (3% bovine serum albumin, BSA) containing PBS (pH 6.8), respectively. The test solutions were injected into the fertilized hen's eggs via air sac at the beginning of the incubation. Various concentrations of a highly embryotoxic substance, AFB1, was also used as positive control test material. Mortality of the AFB1 treatment groups increased with increasing concentrations of AFB1 and the mortality values were significantly (p < 0.05) higher than those of the controls and eluent injected groups. The eluents of five commercially available dental alloys tested in the study did not have significant embryotoxic effects. Cu‐ and Pd‐containing alloys displayed relatively high but statistically insignificant embryotoxic effects. Chick embryo might be used in determination of the embryotoxic effects of the dental alloys with its several advantages. Nevertheless, the test should be further standardized and new methods such as micronucleus test showing possible genotoxic effects of the materials should be used. © 2004 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater 72B: 322–327, 2005
Modulation of 1α,25‐dihydroxyvitamin D3‐membrane associated, rapid response steroid binding protein expression in mouse odontoblasts by 1α,25‐(OH)2D3
Authors: Teillaud Christophe , Nemere Ilka , Boukhobza Florine , Mathiot Claire , Conan Nicole , Oboeuf Martine , Hotton Dominique , MacDougall Mary , Berdal Ariane
Published: November 2004

The rapid, nongenomic effects of 1α,25‐dihydroxyvitamin D3 (1α,25‐(OH)2D3) have been related to a 1,25D3‐membrane associated, rapid response steroid binding protein or 1,25D3‐[MARRS]bp, with a molecular weight of 65 kDa, in several tissues and species. Currently, no information is available concerning the nongenomic responses to 1α,25‐(OH)2D3 in dental tissues. In order to investigate the expression of 1,25D3‐[MARRS]bp in dental cells, in the presence or absence of 1α,25‐(OH)2D3, we have used rabbit polyclonal antibodies directed against the N‐terminus of the 1,25D3‐[MARRS]bp (Ab099) that recognizes the 1α,25‐(OH)2D3 binding protein in chick intestinal basolateral membranes and a mouse odontoblast‐like cell line (MO6‐G3). Western blotting and flow cytometric analyses with Ab099 specifically detected 1,25D3‐[MARRS]bp in MO6‐G3 cells. Moreover, 1,25D3‐[MARRS]bp was up‐regulated, in vivo, in differentiated dental cells. Electron microscopic analysis confirmed the plasma membrane localization of this binding protein and also showed its intracellular presence. Incubation of MO6‐G3 cells with different doses of 1α,25‐(OH)2D3 for 36 h resulted in an inhibition of 1,25D3‐[MARRS]bp expression with a maximal effect at 50 nM steroid. In addition, the culture media of MO6‐G3 cells contains immunoreactive 1,25D3‐[MARRS]bp. Immunogold positive membrane vesicle‐like structures are present in the extracellular matrix of MO6‐G3 cells. Altogether, these results indicate that the 1,25D3‐[MARRS]bp expression in MO6‐G3 cells is modulated by 1α,25‐(OH)2D3. In conclusion, this 1α,25‐(OH)2D3 binding protein could play an important role in the rapid, nongenomic responses to 1α,25‐(OH)2D3 in dental cells. © 2004 Wiley‐Liss, Inc.
Specificity of transcriptional regulation by the zinc finger transcription factors Sp1, Sp3, and Egr‐1
Authors: Al‐Sarraj Alia , Day Regina M. , Thiel Gerald
Published: November 2004

The transcription factors Sp1, Sp3, and Egr‐1 bind with their zinc finger DNA‐binding domains to GC‐rich sequences in the regulatory regions of their target genes. The similarity of the DNA‐binding sites of Sp1, Sp3, and Egr‐1 has triggered the hypothesis that they compete for the same DNA‐binding site. We have investigated the specificity of transcriptional regulation by Sp1, Sp3, and Egr‐1 using dominant‐negative mutants that block the DNA‐binding site of Sp1, Sp3, or Egr‐1, respectively. The results show that constitutive transcription of Sp1 regulated reporter genes, containing Sp1 sites derived from the aldolase C and p21WAF1/Cip1 genes, or the long terminal repeat of HIV‐1, was impaired by dominant‐negative mutants of Sp1 and Sp3, but not by a dominant‐negative Egr‐1. Transcription mediated by Egr‐1 was induced by transfection of expression vectors encoding wild‐type or mutated Egr‐1 or by stimulation of the extracellular signal‐regulated protein kinase pathway via an inducible B‐Raf‐estrogen receptor fusion protein. In all cases transcription of Egr‐1‐regulated reporter genes, containing Egr‐1 binding sites derived from the Egr‐1 or the synapsin I gene was impaired by a dominant‐negative Egr‐1, but not by dominant‐negative Sp1 or Sp3 mutants. These results show that there are genuine Sp1/Sp3 or Egr‐1 controlled genes showing no cross‐regulation of Sp1/Sp3 and Egr‐1 through the same DNA‐binding site. This does not exclude the existence of composite Sp1/Sp3/Egr‐1 binding sites, where competition for a common DNA‐binding site occurs. © 2004 Wiley‐Liss, Inc.
In support of fatty acid synthase (FAS) as a metabolic oncogene: Extracellular acidosis acts in an epigenetic fashion activating FAS gene expression in cancer cells
Authors: Menendez Javier A. , Decker Josiah P. , Lupu Ruth
Published: November 2004

Relatively little information exists on the ultimate molecular mechanisms by which the lipogenic enzyme Fatty Acid Synthase (FAS) is differentially overexpressed in a biologically aggressive subset of human malignancies. Since the microenvironment of solid tumors contains regions of poor oxygenation and high acidity, it has recently been suggested that cancer‐associated FAS is a novel metabolic oncogene conferring a selective growth advantage upon stresses such as hypoxia and/or low pH. Here, we performed transient transfection studies with a 178‐bp FAS promoter fragment harboring a complex Sterol Regulatory Element Binding Proteins (SREBP)‐binding site to evaluate whether extracellular low pH and/or hypoxia may act in an epigenetic fashion by inducing changes in the transcriptional activation of FAS gene in cancer cells. First, MCF‐7 breast cancer cells cultured in acidosis (pH 6.5), but not under hypoxia or in the presence of hypoxia mimetics, demonstrated a more than two‐fold increase in the transcriptional activity of FAS promoter‐reporter constructs compared with control cells grown under standard culture conditions (pH 7.4). Second, the up‐regulatory effect of extracellular acidosis on the transcriptional activation of FAS gene was not observed when the FAS promoter was truncated at the SREBP‐binding site. Third, MCF‐7 cells engineered to overexpress the Her‐2/neu (erbB‐2) oncogene exhibited a SREBP‐dependent activation of the FAS promoter‐reporter construct up to three‐fold higher than that found in wild‐type MCF‐7 cells, while extracellular acidosis resulted only in a marginal increase of Her‐2/neu‐promoted activation of FAS gene. This study reveals for the first time that extracellular acidosis can work in an epigenetic fashion by up‐regulating the transcriptional expression of FAS gene in breast cancer cells, a stimulatory effect that is equally mimicked by well‐characterized oncogenic stimuli such as Her‐2/neu. These findings, altogether, support the “metabolic oncogene” theory for FAS overexpression in cancer cells. © 2004 Wiley‐Liss, Inc.
Method and algorithm of obtaining the molecular intrinsic characteristic contours (MICCs) of organic molecules
Authors: Yang Zhong‐Zhi , Gong Li‐Dong , Zhao Dong‐Xia , Zhang Ming‐Bo
Published: November 2004

The molecular intrinsic characteristic contour (MICC) is defined as the set of all the classical turning points of electron movement in a molecule. Studies on the MICCs of some medium organic molecules, such as dimethylether, acetone, and some homologues of alkanes, alkenes, and alkynes, as well as the electron density distributions on the MICCs, are shown for the first time. Results show that the MICC is an intrinsic approach to shape and size of a molecule. Unlike the van der Waals hard‐sphere model, the MICC is a smooth contour, and it has a clear physical meaning. Detailed investigations on the cross‐sections of MICCs have provided a kind of important information about atomic size changing in the process of forming molecules. Studies on electron density distribution on the MICC not only provide a new insight into molecular shape, but also show that the electron density distribution on the boundary surface relates closely with molecular properties and reactivities. For the homologues of alkanes,R,Dmin, andDmax(the minimum and maximum of electron density on the MICC), all have very good linear relationships with minus of the molecular ionization potential. This work may serve as a basis for exploring a new reactivity indicator of chemical reactions and for studying molecular shape properties of large organic and biological molecules. © 2004 Wiley Periodicals, Inc. J Comput Chem 26: 35–47, 2005
Differential carnitine/acylcarnitine translocase expression defines distinct metabolic signatures in skeletal muscle cells
Authors: Peluso Gianfranco , Petillo Orsolina , Margarucci Sabrina , Grippo Pasquale , Melone Mariarosa Anna Beatrice , Tuccillo Franca , Calvani Menotti
Published: November 2004

Import of acylcarnitine into mitochondrial matrix through carnitine/acylcarnitine‐translocase (CACT) is fundamental for lipid catabolism. To probe the effect of CACT down‐expression on lipid metabolism in muscle, human myocytes were stably transfected with CACT‐antisense construct. In presence of low concentration of palmitate, transfected cells showed decreased palmitate oxidation and acetyl‐carnitine content, increased palmitoyl‐carnitine level, and reduced insulin‐dependent decrease of fatty acylcarnitine‐to‐fatty acyl‐CoA ratio. The augmented palmitoyl‐carnitine synthesis, also in the presence of insulin, could be related to an altered regulation of carnitine‐palmitoyl‐transferase 1 (CPT 1) by malonyl‐CoA, whose synthesis is dependent by the availability of cytosolic acetyl‐groups. Indeed, all the described effects were completely overcome by CACT neo‐expression by recombinant adenovirus vector or by addition of acetyl‐carnitine to cultures. Acetyl‐carnitine effect was related to an increase of malonyl‐CoA and was abolished by down‐expression, via antisense RNA strategy, of acetyl‐CoA carboxylase‐β, the mitochondrial membrane enzyme involved in the direct CPT 1 inhibition via malonyl‐CoA synthesis. Thus, in our experimental model the modulation of CACT expression has consequences for CPT 1 activity, while the biologic effects of acetyl‐carnitine are not associated with a generic supply of energy compounds but to the anaplerotic property of the molecule. © 2004 Wiley‐Liss, Inc.
Gene marking of human neural stem/precursor cells using green fluorescent proteins
Authors: Navarro‐Galve Beatriz , Villa Ana , Bueno Carlos , Thompson Lachlan , Johansen Jens , Martínez‐Serrano Alberto
Published: November 2004

Background

Ex vivo gene therapy and cell replacement in the nervous system may provide therapeutic opportunities for neurodegenerative disorders. The development of optimal gene marking procedures for human neural stem cells (hNSCs) is crucial for the success of these strategies, in order to provide a correct understanding of the biology of transplanted cells.

Methods

hNSCs were modified to express various members of the green fluorescent protein family of proteins. Both DNA and retroviral expression vectors were used. Cells were analyzed for transgene expression under transient and stable expression schemes, and in the presence or absence of drug selection, by fluorescence microscopy, histochemistry, immunocytochemistry, immunoblotting, RT‐PCR and flow cytometry. Genetically marked cells were analyzed in vivo after intrastriatal transplantation in neonatal rats.

Results

Using the same experimental procedures, we have compared Aequorea victoria enhanced green fluorescent protein (Av‐eGFP) and Renilla raniformis GFP (Rh‐GFP, h‐ from humanized) for the purpose of gene marking of hNSCs. Our findings revealed practical problems for the derivation of stable Av‐eGFP‐expressing hNSCs, whereas Rh‐GFP could be well expressed. In a second phase of the study, stable Rh‐GFP‐expressing clonal hNSCs were derived. Rh‐GFP did not interfere with the differentiation potential of the cells, and expression levels were identical between division and differentiation conditions. Thirdly, in vivo, we have confirmed the usefulness of Rh‐GFP for the study of the transplant performance of hNSCs, and demonstrated that Rh‐GFP does not interfere with multipotency and differentiation.

Conclusions

Searching for suitable and useful reporter genes, we have found that Rh‐GFP works efficiently for the purpose of stable gene marking of hNSCs, and is highly useful in vivo. The nature, properties, and possible side effects of marker genes are discussed, since these are important parameters to consider in gene marking studies involving hNSCs. Copyright © 2004 John Wiley & Sons, Ltd.
Similar substituent effects in the oxidations of primary aliphatic alcohols with dichromates and halochromates of heterocyclic bases
Authors: Karunakaran C. , Suresh S.
Published: November 2004

The reaction constants for the oxidations of primary aliphatic alcohols with 12 dichromates and halochromates of heterocyclic bases do not differ significantly indicating operation of a common mechanism. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 37: 5–9, 2005
Additive effect of hydrocarbons on OH radical production in H2 oxidation
Authors: Hidaka Yoshiaki , Ohnishi Takaaki , Wakamatsu Hitoshi
Published: November 2004

Mixtures of hydrocarbons (methane, allene, propyne, propene, and propane)–H2–O2 highly diluted with argon were heated to a temperature ranging from 1200 to 1900 K behind reflected shock waves, and the additive effects of methane, allene, propyne, propene, and propane on OH radical production in H2 oxidation were studied by observing time‐resolved UV‐absorption (306.7 nm). It was found that, in H2 oxidation below 1500 K, the addition of these hydrocarbons prolonged the delay time of the onset of the rapid OH radical production. An analysis using reported kinetic modeling of C1–C4 oxidation gave valuable information for reactions between hydrocarbons and H, O atoms and OH radicals. © 2004 Wiley Periodicals, Inc. Int J Chem Kinet 37: 50–55, 2005
Multiphase Polymer Dispersions and Nanocomposites by Catalytic/Free Radical Emulsion Polymerization
Authors: Kolb Ludmila , Thomann Ralf , Mecking Stefan
Published: November 2004

Summary: Free radical emulsion polymerization of styrene (S) or butyl acrylate (BA) in the presence of latices of linear polyethylene (PE) prepared by catalytic emulsion polymerization affords colloidally stable multiphase latices. Coagulation of a PE/PS latex affords nanocomposites composed of small PE phases dispersed in a PS matrix, as evidenced by the large supercoolings of PE crystallization (by DSC). TEM of PE/PBA latices indicates a PBA phase around the PE particles under the emulsion polymerization conditions investigated. Films formed from these dispersions exhibit homogeneously dispersed PE particles.

Multiphase latices are obtained by free radical emulsion polymerization of butyl acrylate in the presence of latices of linear polyethylene (PE) prepared by catalytic emulsion polymerization.

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Multiphase latices are obtained by free radical emulsion polymerization of butyl acrylate in the presence of latices of linear polyethylene (PE) prepared by catalytic emulsion polymerization.
Synthesis and Properties of Highly Photoluminescent and Electrochemically Active Polymers Containing 2‐Pyrazoline Units in the Main Chain
Authors: Fang Qiang , Jiang Biao , Xu Bing , Cao Amin
Published: November 2004

Summary: Two new polymers containing 2‐pyrazoline units in the main chain were synthesized for the first time by a Suzuki polycondensation between a 2‐pyrazoline monomer and aryl diboronic esters. The polymers showed high photoluminescence (PL) in both the solution and the solid state; quantum yields of PL in toluene were higher than 76%. Thermogravimetric analysis and cyclic voltammetry showed that the polymers had high thermal stability and good reversibility under electrochemical oxidation.

New polymers (2 and 3) with strong photoluminescence and good reversibility under electrochemical oxidation were synthesized here.

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New polymers (2 and 3) with strong photoluminescence and good reversibility under electrochemical oxidation were synthesized here.
Modification of Soy Protein for Wood Adhesives using Mussel Protein as a Model: The Influence of a Mercapto Group
Authors: Liu Yuan , Li Kaichang
Published: November 2004

Summary: Mussel protein can serve as a strong and water‐resistant adhesive, but is expensive and not readily available. Soy protein is inexpensive, abundant, and readily available, but is a poor adhesive. Mussel protein contains a high amount of mercapto‐containing cysteine. This study revealed that increasing the free mercapto group content in soy protein could greatly increase the strength and water‐resistance of wood composites bonded with the modified soy protein.

Preparation of the modified SPIs.

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Preparation of the modified SPIs.
Heat Shrinkable Behavior and Mechanical Response of a Low‐Density Polyethylene/Millable Polyurethane/Organoclay Ternary Nanocomposite
Authors: Mishra Joy K. , Kim Il , Ha Chang‐Sik
Published: November 2004

Summary: A low‐density polyethylene (LDPE)/millable polyurethane (PU)/organoclay ternary nanocomposite was successfully prepared. The nanocomposites were characterized by X‐ray diffraction (XRD) and transmission electron microscopy (TEM). The nanocomposites, as evidenced by XRD, are intercalated. The heat shrinkable behavior of the nanocomposites, as well as their pristine counterparts, was studied. It was observed that heat shrinkability decreases with increased filler content. The tensile strength and the tensile modulus of the nanocomposites are higher than their pristine counterparts.

The heat shrinkability of the unfilled LDPE/millable PU blend is highest and it decreases with increased nanofiller content.

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The heat shrinkability of the unfilled LDPE/millable PU blend is highest and it decreases with increased nanofiller content.
Cover Picture: Macromol. Rapid Commun. 21/2004
Authors: Leung Man Fai , Zhu Junmin , Harris Frank W. , Li Pei
Published: November 2004

Cover: A transmission electron microscope image of microgel particles that consist of well‐defined temperature‐sensitive poly(N‐isopropylacrylamide) cores with pH‐sensitive chitosan shells is shown. The microgels are obtained directly from aqueous graft copolymerization of N‐isopropylacrylamide and N,N‐methylenebisacrylamide from chitosan. The unique core‐shell nanostructure exhibits tuneable responses to pH and temperature.

Further details can be found in the Communication by M. F. Leung, J. Zhu, F. W. Harris, and P. Li* on page 1819.
Medial dorsal superficial peroneal nerve studies in patients with polyneuropathy and normal sural responses
Authors: Kushnir Mark , Klein Colin , Kimiagar Yitzhak , Pollak Lea , Rabey Jose M.
Published: November 2004

We studied medial dorsal superficial peroneal (MDSP) nerves in 52 patients with clinical evidence of mild chronic sensorimotor polyneuropathy and normal sural nerve responses, in order to assess the diagnostic sensitivity and usefulness of MDSP nerve testing in electrodiagnostic practice. To determine the effect of age on MDSP nerve parameters, 98 normal subjects were also examined. Electrodiagnostic evaluation involved studies of motor nerve conduction in tibial, peroneal, and median nerves; sensory nerve conduction in sural, MDSP, median, and radial nerves; tibial and peroneal nerve F waves; H reflexes from the soleus muscles; and needle electromyography of gastrocnemius and abductor hallucis muscles. Among the patients, 49% had low‐amplitude sensory responses in MDSP nerves and 57% had either slowing of sensory conduction velocity or no sensory responses on proximal stimulation. MDSP nerve amplitude, tibial nerve motor velocity, and H reflexes were the most sensitive for detection of mild chronic symmetrical axonal sensorimotor polyneuropathy. MDSP nerve testing should be included in the routine electrodiagnostic evaluation of patients with suspected polyneuropathy and normal sural nerve responses. Muscle Nerve, 2005
Peripheral neuropathy in hepatitis‐related mixed cryoglobulinemia: Electrophysiologic follow‐up study
Authors: Ammendola Angelo , Sampaolo Simone , Ambrosone Lucia , Ammendola Eduardo , Ciccone Gianluca , Migliaresi Sergio , Di Iorio Giuseppe
Published: November 2004

A retrospective study was performed on 27 patients with hepatitis C (HCV)–related mixed cryoglobulinemia (purpura, arthralgia, hepatitis, glomerulonephritis, peripheral neuropathy) to assess peripheral nerve involvement during follow‐up of up to 8 years. All patients had the same degree of organ/system involvement initially and were clinically evaluated at least annually. All 27 patients received steroids; 15 also received recombinant interferon‐α2b (rIFN‐α2b). At first examination, neurological signs and electrodiagnostic findings consistent with peripheral neuropathy were found in 20 (74%) and in 24 (88.8%) patients, respectively. Neurological evaluation and electrodiagnostic data at 3 and 8 years revealed worsening of neuropathy, whereas the other manifestations of mixed cryoglobulinemia (MC) were stable. At the last examination, clinical and electrodiagnostic signs of neuropathy were found in 25 patients (92.5%), occurring in 1 of 3 patients with normal initial findings, and worsened in 8. A more severe neuropathy was observed in 3 (25%) of the patients treated with prednisone alone and in 6 (40%) of the patients additionally treated with rIFN‐α2b. Our data confirm that in patients with HCV‐related MC, peripheral nerve involvement is frequent, is progressive, and does not seem to benefit by addition of rIFN‐α2b to steroid treatment. Muscle Nerve, 2005
Myotonia and muscle contractile properties in mice with SIX5 deficiency
Authors: Personius Kirkwood E. , Nautiyal Joyti , Reddy Sita
Published: November 2004

Myotonic dystrophy (DM1) is an autosomal‐dominant multisystem disease characterized by progressive skeletal muscle weakness, myotonia, cataracts, cardiac arrhythmias, mild mental retardation, and endocrinopathies. Heterozygous loss of SIX5 in mice causes cataracts and cardiac conduction disease, and homozygous loss also leads to sterility and decreased testicular mass, reminiscent of DM1 in humans. The effect of SIX5 deficiency in muscle is unknown. In this study, we found that muscle contractile properties, electromyographic insertional activity, and muscle histology were normal in SIX5 deficient mice. The implications of these findings for the pathogenesis of DM1 are discussed. Muscle Nerve, 2004