bluuebunny/crossref_metadata_2025 huggingface dataset:
Alterations of somatotropic function in prion disease in sheep
Authors: Viguié C , Chilliard Y , Gayrard V , Picard-Hagen N , Monget P , Dutour A , Toutain P-L
Published: December 2004

This study aimed at investigating the possible linkage between natural scrapie and alterations of the somatotropic axis. Scrapie-affected ewes exhibited 2-fold higher mean GH concentrations during both autumn and spring. GH pulse frequencies were higher in scrapie-affected ewes than in control animals (mean±S.E.M. number of pulses/24 h: 10.4±0.9 and 7.6±0.9 for scrapie-affected and control ewes respectively) suggesting the involvement of central mechanisms. GH secretion induced by administration of an α2-adrenergic agonist, which acts centrally to stimulate GH secretion, was similar between healthy and scrapie-affected ewes (ratios of the area under the curve (AUC) of GH concentration after to the GH AUC before the agonist administration were 3.6±1.6 and 4.9±1.0 for scrapie-affected and control ewes respectively). Finally, humoral markers and parameters of the metabolic status were determined to test the hypothesis that scrapie-associated alterations of GH secretion could be related to disruption of metabolic homeostasis. Glucose, insulin and urea plasma concentrations were higher in scrapie-affected than in healthy ewes. Neither leptin nor IGF-I levels were affected by scrapie. Total thyroxine (T4) was decreased in scrapie-affected ewes but free T4 and total and free triiodothyronine were not modified. In conclusion, our results showed the existence in scrapie-affected ewes of endocrine and metabolic alterations typical of acute illness proceeding, at least in part, from central mechanisms.
Effects of GnRH antagonist treatment on follicular development and angiogenesis in the primate ovary
Authors: Taylor P D , Hillier S G , Fraser H M
Published: December 2004

Angiogenesis is required for normal follicular development but the role of gonadotrophins in the control of follicular angiogenesis remains to be elucidated. This study investigated the effects of treatment with GnRH antagonist in vivo on follicular development and angiogenesis in the marmoset. GnRH antagonist was administered on either follicular day 0 or day 5 of the 10-day follicular phase with ovaries collected on day 10. Ovaries from control marmosets were studied at day 5 (mid follicular phase) and day 10 (periovulatory period). Ovaries were fixed, serial sectioned and subjected to morphological analysis and immunocytochemistry to determine cell proliferation and follicular endothelial cell area and in situ hybridization to assess changes in expression of vascular endothelial growth factor (VEGF). Treatment with GnRH antagonist from day 0–10 resulted in an absence of dominant preovulatory follicles seen in controls. In the remaining tertiary follicles granulosa, theca and endothelial cell proliferation was reduced, resulting in a minor reduction in vascular density. However, VEGF mRNA expression was unaffected by treatment. Treatment from day 5–10 did not prevent development of ovulatory size follicles, but they were atretic and lacked VEGF mRNA. These results suggest that while VEGF expression in the preovulatory follicle is under gonadotrophic control it is not dependent on normal gonadotrophin secretion in tertiary follicles, indicating that there are other paracrine factors regulating VEGF expression in the developing ovarian follicle.
Steroid signalling in human ovarian surface epithelial cells: the response to interleukin-1α determined by microarray analysis
Authors: Rae M T , Niven D , Ross A , Forster T , Lathe R , Critchley H O D , Ghazal P , Hillier S G
Published: December 2004

The human ovarian surface epithelium (HOSE) is a common site of gynaecological disease including endometriosis and ovarian cancer, probably due to serial injury-repair events associated with successive ovulations. To comprehend the importance of steroid signalling in the regulation of the HOSE, we used a custom microarray to catalogue the expression of over 250 genes involved in the synthesis and reception of steroid hormones, sterols and retinoids. The array included a subset of non-steroidogenic genes commonly involved in pro-/anti-inflammatory signalling. HOSE cells donated by five patients undergoing surgery for non-malignant gynaecological conditions were cultured for 48 h in the presence and absence of 500 pg/ ml interleukin-1α (IL-1α). Total RNA was reverse-transcribed into biotin-labelled cDNA, which was hybridised to the array and visualised by gold-particle resonance light scattering and charge-coupled device (CCD) camera detection. Results for selected genes were verified by quantitative reverse-transcription PCR. In five out of five cases, untreated HOSE cells expressed genes encoding enzymes required for de novo biosynthesis of cholesterol from acetate and subsequent formation of C21-pregnane and C19-androstane steroids. Consistent with the inability of HOSE cells to synthesise glucocorticoids, oestrogens or 5α-reduced androgens de novo, CYP21, CYP19 and 5α-reductase were not detected. The only steroidogenic gene significantly up-regulated by IL-1α was 11β-hydroxysteroid dehydrogenase type 1 (11βHSD1). Other cytokine-induced genes were IL-6, IL-8, nuclear factor κB (NFκB) inhibitor α, metallothionein-IIA and lysyl oxidase: inflammation-associated genes that respond to glucocorticoids. The only steroidogenic gene significantly suppressed by IL-1α was 3βHSD1. Other genes suppressed by IL-1α were aldehyde dehydrogenase (ALDH) 1, ALDH 10, gonadotrophin hormone-releasing hormone receptor, peroxisome proliferation-activated receptor-binding protein (PPAR-bp) and nuclear receptor subfamily 2 group F member 2. These results define a steroidogenic phenotype of cultured HOSE cells and provide a limited expression profile for genes with associated signalling functions. IL-1α co-ordinately induces 11βHSD1 and a panel of glucocorticoid-regulated, inflammation-associated genes in HOSE cells, providing further evidence that cortisol generated by 11βHSD1 could participate in the local resolution of inflammation associated with ovulation.
Glucocorticoid down-regulation of rat glucocorticoid receptor does not involve differential promoter regulation
Authors: Freeman Alistair I , Munn Helen L , Lyons Val , Dammermann Alexander , Seckl Jonathan R , Chapman Karen E
Published: December 2004

The level of expression of the glucocorticoid receptor (GR) is the principal determinant of glucocorticoid sensitivity in most cells. GR levels are permanently ‘set’ in a tissue-specific manner in response to the perinatal environment, an effect we have previously shown to relate to differential expression of tissue-enriched alternative promoters/exons 1 of the GR gene. In adult animals, GR levels are dynamically regulated around the ‘set point’ by glucocorticoids themselves, with glucocorticoids down-regulating GR mRNA in most cells and tissues. Here we have examined whether autoregulation of GR mRNA by glucocorticoids involves differential promoter regulation. We show that, in contrast to tissue-specific programming of GR mRNA levels, autoregulation of GR mRNA in vivo does not involve differential regulation of variant exon 1-containing GR mRNAs in that the major variants are down-regulated to a similar extent by glucocorticoid treatment. Consistent with this, transfections of reporter constructs showed that the majority of GR promoters, which are contained within a 4.4 kb region upstream of exon 2, are similarly regulated by glucocorticoids, with two regions of the promoter redundantly required for glucocorticoid regulation. Thus transcriptional autoregulation can occur in adult tissues around the set point established by promoter selection in early life.
Hepatocyte growth factor regulates proliferation and differentiation of epithelial monolayers derived from islets of postnatal rat pancreas
Authors: Wang R , Yashpal N , Bacchus F , Li J
Published: December 2004

Hepatocyte growth factor (HGF) has been suggested to be a potent regulator of β-cell function and proliferation. The purpose of this study was to investigate whether HGF could regulate the proliferation and differentiation of islet-derived epithelial monolayers into insulin-producing cells. We have generated islet-derived epithelial monolayers that are enriched with cells expressing c-Kit, a tyrosine kinase receptor and putative marker, from isolated postnatal rat islets. Monolayers were cultured on type I collagen gel and treated in defined differentiation medium with or without HGF (50 ng/ml) for 7 days. Subsequently, the expression of transcription factors and pancreatic endocrine cell markers as well as c-Kit expression were compared between the HGF (HGF+), no HGF treatment (HGF−) and monolayers without differentiation medium (control) groups, using immunocytochemical and RT-PCR approaches. We observed that the number of c-Kit-, glucose transport type 2 (Glut2)- and the transcription factor pancreatic duodenal homeobox-1 (PDX-1)-expressing cells were significantly increased in the HGF+ group. The expression of insulin at the mRNA and protein level was also increased in this treatment group with a 1.7-fold increase in basal insulin release and a 2.3-fold increase in insulin content in comparison with the HGF− group. A high proliferative capacity was also found in the HGF+ group. Co-localization of insulin and PDX-1 or Glut2 was revealed frequently in cells treated with HGF+ with occasional co-staining of c-Kit and insulin observed. This study showed that HGF can activate the proliferation and differentiation of islet-derived epithelial monolayer into insulin-producing cells. However, no formation of islet-like clusters was observed. Taken together, this study implies that HGF mediates differentiation of immature cell types into insulin-expressing cells; however, HGF supplementation alone is insuffcient in restoring full β-cell function.
Islet neogenesis: an apparent key component of long-term pancreas adaptation to increased insulin demand
Authors: Del Zotto H , Borelli M I , Flores L , García M E , Gómez Dumm C L , Chicco A , Lombardo Y B , Gagliardino J J
Published: December 2004

This study aimed to determine the relative importance of different functional and morphological pancreatic changes induced by the chronic administration of a sucrose-rich diet (SRD) to maintain normal glucose homeostasis. Male Wistar rats were fed either sucrose (SRD) or starch (CD) for 6 and 12 months. At both periods, serum glucose and triacylglycerol levels were significantly higher (P<0.05; paired and unpaired Student’s t-test) in SRD rats. Serum insulin levels were significantly lower in SRD only at 12 months. At 6 months, the insulin secretion dose–response curve in SRD rats showed a shift to the left that was no longer observed at 12 months, when SRD islets decreased their response to 16 mM glucose. At 6 months, SRD rats showed a significant increase in β-cell volume density (Vvi) and islet cell replication rate, together with a decrease in β-cell apoptotic rate. Changes were not detected in the percentage of PDX-1- and islet neogenesis associated protein (INGAP)-positive cells. Conversely, at 12 months, there was a significant decrease in β-cell Vvi and in the percentage of PDX-1-positive cells; the islet cell replication rate was not modified, and the number of apoptotic β-cells increased significantly. No signs of increased neogenesis or INGAP-positive cells were recorded at any period in SRD rats. Our results show that SRD rats are unable to develop functional and morphological pancreatic reactive changes sufficient to maintain normal glucose and triacylglycerol levels for a long period. Such failure could be ascribed to their inability to increase the rate of neogenesis and of INGAP production.
QSOX sulfhydryl oxidase in rat adenohypophysis: localization and regulation by estrogens
Authors: Tury A , Mairet-Coello G , Poncet F , Jacquemard C , Risold P Y , Fellmann D , Griffond B
Published: December 2004

The expression of the rat quiescin sulfhydryl oxidase (rQSOX) and its putative regulation by estrogens were investigated in the adenohypophysis. Immunohistochemical observations revealed that rQSOX protein is abundantly expressed throughout the anterior lobe of the pituitary, and can be found in almost all the different cell populations. However, as shown by double immunohisto-chemistry, the cells displaying the strongest rQSOX labeling belong to a subset of gonadotrophs. Immunoelectron microscopy showed that, in adenohypophyseal cells, the protein is linked to the membranes of the rough endoplasmic reticulum, the Golgi apparatus and to dense-core secretory granules. These results are consistent with the secretion of the protein and its presumed role in the extracellular matrix. According to its sulfhydryl oxidase function, rQSOX could also participate in the intracellular folding of secreted proteins or hormones like LH and FSH and act as an endogenous redox modulator of hormonal secretion. A semiquantitative RT-PCR analysis of rQSOX level across the estrous cycle and the fact that chronic administration of 17 β-estradiol to ovariectomized rats led to a sustained up-regulation of rQSOX in the pituitary suggest that rQSOX expression is controlled by sex hormone levels. Further investigations are needed in order to elucidate its precise roles in that gland and the mechanisms of its regulation.
How thyroid tumors start and why it matters: kinase mutants as targets for solid cancer pharmacotherapy
Authors: Fagin J A
Published: December 2004

Treatment of patients with thyroid cancer is usually successful, and most patients are cured of the disease. However, we do not have effective therapies for patients with invasive or metastatic thyroid cancer if the disease is not surgically resectable and does not concentrate radio-iodine. Conventional external beam radiotherapy and chemotherapy are of marginal benefit. In other types of cancer, new therapies are being developed that take advantage of our knowledge of cancer pathogenesis to interfere with the activity of specific oncoproteins believed to be important in disease causation. Because these approaches are being considered for thyroid cancer, I will briefly describe in this review examples of recent breakthroughs in medical therapy of certain hematological malignancies and some solid tumors using drugs that work in this fashion, focusing in particular on compounds that block the enzymatic activity of specific tyrosine kinase oncoproteins. It should be noted, however, that cancers commonly harbor mutations or other disruptions of many genes, each of which could conceivably play a role in disease pathogenesis. This makes the choice of molecular target a difficult and critical decision if these approaches are to succeed. Here I will argue that priority should be given to blocking the function of oncoproteins activated early in tumor development. We have a fairly good understanding of the genetic changes involved in thyroid cancer initiation, and hence these cancers may prove to be particularly well suited for oncoprotein-specific therapies.
Method for the determination of primary, secondary, and tertiary amino groups in star‐shaped polyamide 12 with a poly(ethylene imine) core
Authors: Baumann F. E. , Haeger H. , Novikova O. , Oenbrink G. , Richter R.
Published: December 2004

A star‐branched poly(ethylene imine)‐g‐polyamide 12 with a high concentration of primary amino end groups is an object of interest for future chemical modifications. In many cases, the concentration of primary amino groups, which are also the end groups of the polyamide 12 arms, and the concentrations of secondary and tertiary amino groups in a sample need to be known independently. Because of the difference in the reactivity of phthalic acid toward amino groups, its reaction with poly(ethylene imine)‐g‐polyamide 12 can be used for the analytical determination of these groups. With primary amino groups, phthalic acid forms phthalimido moieties, which are detectable by IR spectroscopy. The IR bands can be used for quantitative analysis with an appropriate calibration procedure. The concentration of primary amino groups can also be calculated as the difference between the concentration of all types of amino groups before the reaction with phthalic acid and the final concentration of amino and carboxylic groups after the reaction. The final concentration of the amino groups is equal to the concentration of unreacted tertiary amino groups after the reaction with phthalic acid anhydride. The difference between the final concentration of carboxylic groups and the initial concentration of carboxylic groups is equivalent to the concentration of secondary amino groups, which react with phthalic acid to form phthalamido acid moieties. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 556–563, 2005
Crystallization behavior of poly(N‐methyldodecano‐12‐lactam). IV. Nonisothermal crystallization
Authors: Kratochvíl J. , Sikora A.
Published: December 2004

Nonisothermal crystallization of poly(N‐methyldodecano‐12‐lactam) (MPA) was investigated using DSC method at cooling rates of 2–40 K/min. With increasing cooling rate, crystallization exotherms decreased in magnitude and shifted toward lower temperatures. Subsequent heating runs (10 K/min) showed an exotherm just above Tg, which increased in magnitude with the rate of preceding cooling run, corresponding to the continuation of primary crystallization interrupted as the system crossed Tg on cooling. Kinetic evaluation by the Avrami method gave values of exponent n close to 2.0, suggesting two‐dimensional crystal growth combined with heterogeneous nucleation. The Tobin method, covering the intermediate range of relative crystallinities, provided n ≅ 2.20, suggesting possible partial involvement of homogeneous nucleation at later stages of nonisothermal crystallization. The crystallization rate parameter k1/n showed a linear dependency on cooling rate for both methods, the Tobin values being slightly higher. The Ozawa approach failed to provide reasonable values of the kinetic exponent m of MPA. The Augis–Bennet method was used to determine the effective activation energy of the entire nonisothermal crystallization process of MPA. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 564–572, 2005
Synthesis of the glycidyl aniline adduct and its crosslinking
Authors: Gawdzik Barbara , Matynia Tadeusz , Kovtun Oksana
Published: December 2004

Synthesis of the adduct of aniline and glycidyl methacrylate and its polymerization and copolymerization with two diisocyanates are presented. Hexyl diisocyanate representing aliphatic compounds and toluene diisocyanate as the aromatic compound were used. UV and thermal initiations were applied. The curing process was controlled by FTIR analysis. Thermomechanical properties of the compositions cured at different temperatures were compared. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 524–528, 2005
Chemical oxidative grafting of conducting poly(N‐methyl aniline) onto poly(ethylene terepthalate)
Authors: Santhosh P. , Mathanmohan T. , Sankarasubramanian M. , Sankar S. , Vasudevan T. , Gopalan A. , Lee Kwang‐Pill
Published: December 2004

Detailed studies on the peroxidisulfate (PDS) initiated graft copolymerization of N‐methyl aniline (NMA) with poly(ethylene terepthalate) (PET) were carried out in p‐tolene sulfonic acid medium under nitrogen atmosphere. Experiments were designed to follow the rate of formation Rh of the poly(N‐methyl aniline (PNMA), simultaneously with the rate of grafting of PNMA onto PET. Effects of concentration of NMA, PDS, PET, time, and temperature on Rh and graft parameters were followed. Kinetic equations were deduced to correlate the changes in the rate with experimental conditions. Graft copolymers were isolated and grafting of PNMA onto PET was confirmed through FTIR, thermogravimetric analysis, and conductivity measurements. Tensile measurements showed that grafting of PNMA did not alter the tensile properties of PET. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 596–605, 2005
Aromatic polyesters based on bisphenol‐A for liquid insulating systems: A synthetic approach
Authors: Shenoy M. A. , Pereira E. A. , Parikh P. F.
Published: December 2004

This work concentrates on the area of the synthesis of polymers for liquid insulating systems. We have studied reactions of aromatic esters like diphenyl terephthalate/isophthalate, diphenyl carbonate with Bisphenol‐A, and tri functional glycerol for the synthesis of aromatic polyesters that can be used as liquid insulating systems. The process comprises a transesterification resin synthesis based on a single pot process, with a temperature profile up to 250°C and an inert atmosphere of nitrogen. The byproduct of the phenol is continuously removed under a steady flow of nitrogen to enable polycondensation. The resins obtained were tested for their physical properties, such as melting range, relative viscosity, and hydroxyl value. These resins were also used in solution film formation to establish their film forming properties. The method explored is the simplest one, and permits the use of commercial materials as the feedstock. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 95: 606–614, 2005
Cystathionine β synthase deficiency affects mouse endochondral ossification
Authors: Robert Karine , Maurin Nicole , Vayssettes Catherine , Siauve Nathalie , Janel Nathalie
Published: December 2004

Cystathionine β synthase (CBS) is a crucial regulator of plasma concentrations of homocysteine. Severe hyperhomocysteinemia due to CBS deficiency confers diverse clinical manifestations, notably characteristic skeletal abnormalities. To investigate this aspect of hyperhomocysteinemia, we analyzed the skeleton of CBS‐deficient mice, a murine model of severe hyperhomocysteinemia. Radiography, Alcian Blue/Alizarin Red S‐stained whole skeletal preparations, and histological comparisons were used to determine the extent, pattern, and distribution of skeletal abnormalities in CBS‐deficient mice. Disruption of the murine CBS gene leads to skeletal abnormalities, notably kyphoscoliosis, with temporal shortening of long bones due to impaired cartilage differentiation, albeit to differing degrees. © 2004 Wiley‐Liss, Inc.
Rodent pharmacokinetics and receptor occupancy of the GABAA receptor subtype selective benzodiazepine site ligand L‐838417
Authors: Scott‐Stevens P. , Atack J.R. , Sohal B. , Worboys P.
Published: December 2004

The pharmacokinetics of L‐838417, a GABAA receptor subtype selective benzodiazepine site agonist, were studied in rats and mice after single oral (p.o.), intraperitoneal (i.p.) and intravenous (i.v.) doses. In both species L‐838417 was well absorbed following i.p. administration and whilst in rats p.o. bioavailability was good (41%), in mice it was negligible (<1%), precluding this as a route of administration for mouse behavioural studies. Despite having a similar volume of distribution (ca 1.4 l/kg) in rats and mice, L‐838417 was cleared at twice liver blood flow in mice (161 ml/min/kg) and moderately cleared in rats (24 ml/min/kg), potentially explaining the poor oral bioavailability in mice. Finally, as a pharmacodynamic readout the benzodiazepine binding site occupancy was determined in rats (0.3–3 mg/kg, p.o.) and mice (1–30 mg/kg, i.p.) using a [3H]Ro 15‐1788 in vivo binding assay. Although the resulting dose‐occupancy relationship for both species demonstrated a dose‐dependent increase in receptor occupancy, appreciable variability was observed at low dose levels, potentially making interpretation of behavioural responses difficult. In contrast, a clear relationship between plasma and brain concentrations and receptor occupancy were determined suggesting the observed dose‐occupancy variability is a consequence of the pharmacokinetic properties of L‐838417. The plasma and brain concentrations required to occupy 50% of the benzodiazepine binding sites were similar in both rats (28 ng/ml and 33 ng/mlg, respectively) and mice (63 ng/ml and 53 ng/mlg, respectively), with a non‐linear concentration response observed with increasing doses of L‐838417. These studies demonstrate the importance of utilizing pharmacokinetic/receptor occupancy data when interpreting pharmacodynamic responses at a given dose. Copyright © 2004 John Wiley & Sons, Ltd.
Topological Analysis of Electron Densities: Is the Presence of an Atomic Interaction Line in an Equilibrium Geometry a Sufficient Condition for the Existence of a Chemical Bond?
Authors: Haaland Arne , Shorokhov Dimitry J. , Tverdova Natalya V.
Published: December 2004

Contrary to the published acknowledgement, Professor R. F. W. Bader in no way contributed to any of arguments presented in this paper; he has indicated that all of the criticisms raised by the authors were previously discussed and rebuted in J. Chem. Phys. A 1998, 102, 7314.

A copy of an earlier version of the manuscript was sent to Professor Bader last spring, and the e‐mail correspondence that followed made it very clear that he disagreed strongly with the conclusions. The authors nevertheless found the discussion useful, since it clarified the nature of the disagreement. Professor Bader's queries also prompted the authors to calculate the dissociation energy of the He@adam inclusion complex and to determine the structure of the transition state as discussed in the article. The authors apologize for omitting to ask for Professor Bader's permission to include his name among the acknowledgements.
Effect of Ultrasound on the Redox Reactions of Iron(II) and (III).
Authors: Pankaj Pankaj , Chauhan Manju
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
The Lone‐Pair Cation I5+ in a Hexagonal Tungsten Oxide‐Like Framework: Synthesis, and Second‐Harmonic Generating Properties of Cs2I4O11.
Authors: Ok Kang Min , Halasyamani P. Shiv
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Self‐Supported Heterogeneous Catalysts for Enantioselective Hydrogenation.
Authors: Wang Xingwang , Ding Kuiling
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Novel π‐Extended Donors Containing a 2,2,5,5‐Tetramethylpyrrolin‐1‐yloxyl Radical Designed for Magnetic Molecular Conductors.
Authors: Fujiwara Emiko , Kobayashi Akiko , Fujiwara Hideki , Sugimoto Toyonari , Kobayashi Hayao
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Intermolecular “Oxidative” Aromatic Substitution Reactions of the Imidazol‐5‐yl Radical Mediated by the “Reductant” Bu3SnH.
Authors: McLoughlin Padraig T. F. , Clyne Mairead A. , Aldabbagh Fawaz
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Syntheses of Sulfoxide Derivatives in the Benzodiazine Series. Diazines. Part 37.
Authors: Le Fur Nicolas , Mojovic Ljubica , Turck Alain , Ple Nelly , Queguiner Guy , Reboul Vincent , Perrio Stephane , Metzner Patrick
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
A New Family of Macrocycles Produced by Sequential Claisen—Schmidt Condensations
Authors: Higham Luke T. , Kreher Ulf P. , Raston Colin L. , Scott Janet L. , Strauss Christopher R.
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Catalytic Nanomotors: Autonomous Movement of Striped Nanorods.
Authors: Paxton Walter F. , Kistler Kevin C. , Olmeda Christine C. , Sen Ayusman , St. Angelo Sarah K. , Cao Yanyan , Mallouk Thomas E. , Lammert Paul E. , Crespi Vincent H.
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Large‐Scale Production of NbS2 Nanowires and Their Performance in Electronic Field Emission.
Authors: Jin Yi Zheng , Hsu Wen Kuang , Chueh Yu Lun , Chou Li Jen , Zhu Yan Qiu , Brigatti Kieren , Kroto Harold W. , Walton David R. M.
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Metal‐Assisted Polyhedral Contraction Reactions of Monocarbon and Dicarbon Carbaborane Species Involving nido‐{CB10}, nido‐{CB9}, nido‐{C2B8} and exo‐nido‐{C2B9Os} Systems
Authors: Pisareva I. V. , Konoplev V. E. , Balagurova E. V. , Yanovsky A. I. , Dolgushin F. M. , Cheredilin D. N. , Chizhevsky I. T. , Franken A. , Carr M. J. , Thornton‐Pett M. , et al. et al.
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Direct Insertion into Twelve‐Vertex Metallacarboranes
Authors: Kudinov Alexander R. , Perekalin Dmitry S. , Rynin Stanislav S. , Lyssenko Konstantin A. , Grintselev‐Knyazev Gennadii V. , Petrovskii Pavel V.
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Reactions of Boranes and Metallaboranes with Phosphines
Authors: Barton L. , Volkov O. , Hata M. , McQuade P. , Rath N. P.
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
Synthetic Molecules as Antibody Replacements
Authors: Kodadek Thomas , Reddy M. Muralidhar , Olivos Hernando J. , Bachhawat‐Sikder Kiran , Alluri Prasanna G.
Published: December 2004

For Abstract see ChemInform Abstract in Full Text.
N‐Ferrocenyl‐Substituted Planar‐Chiral N‐Heterocyclic Carbenes and Their PdII Complexes
Authors: Bertogg Andreas , Camponovo Francesco , Togni Antonio
Published: December 2004

The N‐ferrocenyl‐linked N‐heterocyclic carbenes 1a and 1b were obtained by treatment of their imidazolium salts 12a and 12b with potassium tert‐butoxide. The latter were shown to be accessible from (R)‐1‐amino‐2‐methylferrocene (9) and aminoferrocene, respectively, which were converted into the corresponding formamidines and then subjected to a novel cyclization procedure. Treating the ligand precursors 12a and 12b with [Pd(OAc)2]3 under different reaction conditions afforded the trans‐pyridine‐substituted PdII complexes 14a and 14b as well as their trans‐triphenylphosphane‐substituted counterparts 16a and 16b and, in the case of the chiral ligand precursor, the dinuclear PdII complex 15a. Conformational analysis of the ligands based on the X‐ray structures of 12a, 12b and 16a revealed the dependence of the two torsion angles between the central imidazolium core and the adjacent ferrocenyl substituents on the steric and electronic properties of the observed systems. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Base Strengths of Substituted Tritylamines, N‐Alkylanilines, and Tribenzylamine in Aqueous Solution and the Gas Phase: Steric Effects Upon Solvation and Resonance Interactions
Authors: Canle L. Moisés , Demirtas Ibrahim , Freire Antonio , Maskill Howard , Mishima Masaaki
Published: December 2004

The dissociation constants of the conjugate acids of N‐tritylacetamide (1h; pK = 3.81) and N‐benzyl‐N‐methyl‐4,4′,4′′‐trimethoxytritylamine (4i; pK = 9.86) have been measured in aqueous acetonitrile at 25 °C and at other temperatures to determine the enthalpies and entropies of reaction. For 1h, ΔH⊖ = 40.7 kJ·mol−1 and ΔS⊖ = 64 J·K−1·mol−1, and for 4i ΔH⊖ = 9.1 kJ·mol−1 and ΔS⊖ = −159 J·K−1·mol−1. In addition, gas‐phase base strengths at 25 °C (GB values in kJ·mol−1) of TrNH2 (1a; 902.1), TrNHPh (1c; 926.3), TrNHAc (1h; 929.7), TrNHC6H4(o‐NO2) (1i; 895.0), DMTrNH2 (3a; 921.3), DMTrNHCH2CO2Me (3b; 879.1), and DMTrNH(p‐NO2Bn) (3d; 886.6) have been determined by ICR measurements. The GB of TrNHAc corresponds to protonation at oxygen and B3LYP/6‐31G* calculations indicate that the N‐protonated isomer is 46.4 kJ·mol−1 less stable, i.e. the GB value for N‐protonation is 883.3 kJ·mol−1. Correspondingly, the literature GB value of 857.6 5 kJ·mol−1 for N‐methylacetamide corresponds to protonation at oxygen, and B3LYP/6‐31G* calculations indicate that the N‐protonated isomer is 58.1 kJ·mol−1 less stable, i.e. the GB value for N‐protonation of MeNHAc is 799.5 kJ·mol−1. The GB of PhNH(tBu) (5; 920.1 kJ·mol−1) has been measured and compared with values for other N‐alkylanilines, PhNHR, including PhNHTr; the results indicate that the increasing GB values as R increases in size are due solely to the increasing polarisability of R. This indicates that the increasing solution base strength of PhNHR as R increases in size is a solvation effect and is not due to decreasing resonance interactions between the nitrogen lone‐pair and the phenyl ring. Similarly, the base‐strengthening effect in solution of the (substituted) trityl in TrNHZ, where Z is an alkyl with an electron‐withdrawing group, is shown to be due to solvation phenomena as it is absent in the gas phase; for one such compound, TMTrNHCH2CO2Me (4b; pK = 9.30), ΔH⊖ = 17.9 kJ·mol−1 and ΔS⊖ = −118 J·K−1·mol−1. In contrast, the difference in solution base strengths between MeNHAc (pK = −0.56) and TrNHAc (pK = 3.81) is attributed, at least in part, to a reduced base‐weakening resonance interaction between the lone pair on N and the acetyl group in TrNHAc, as the effect is also evident in the gas phase. The GB value for tribenzylamine (6) has also been measured (965.2 kJ·mol−1) and is unexceptional; this indicates that the low base strength of 6 in aqueous solution (pK = 4.90 at 25 °C) is a solvation effect which is expressed mainly through an abnormally large positive entropy of reaction (ΔS⊖ = 76 J·K−1·mol−1), the value of ΔH⊖ (50.5 kJ·mol−1) being only slightly larger than normal for tertiary amines. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Synthesis of the First Tetracene‐[60]fullerene Dyad
Authors: Taillemite Sébastien , Fichou Denis
Published: December 2004

We report on a multistep synthesis of the newly designed tetracene‐[60]fullerene dyad involing a Bingel reaction between the tetracene and C60 moieties. This strategy prevents the usual Diels−Alder reaction which would result in the loss of the tetracene aromaticity in the target dyad. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Encapsulation and Stabilization of Reactive Aromatic Diazonium Ions and the Tropylium Ion Within a Supramolecular Host
Authors: Brumaghim Julia L. , Michels Martin , Pagliero Daniela , Raymond Kenneth N.
Published: December 2004

Supramolecular assemblies with internal cavities are being developed as nanoscale reaction vessels to protect or modify the reactivity of guest species through encapsulation. Diazonium cations and the tropylium cation were examined for their ability to encapsulate in the tetrahedral [Ga4L6]12− supramolecular assembly. The 4‐(diethylamino)benzenediazonium cation 1 readily formed a 1:1 host−guest complex with this assembly, and this encapsulation prevented 1 from reacting with 2,4‐pentanedione in D2O. The tropylium cation also formed a 1:1 host−guest complex with the [Ga4L6]12− assembly, greatly slowing its decomposition in D2O. Encapsulation in the protected environment of this host cavity alters the reactivity of these guest molecules, giving them greater stability. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Silylation‐Mediated Transesterification of O‐Phenyl H‐Phosphonothioates − A New Entry to Nucleoside H‐Phosphonothioate Monoesters
Authors: Lavén Gaston , Nilsson Johan , Stawinski Jacek
Published: December 2004

O‐Phenyl H‐phosphonothioate undergoes a facile transesterification with suitably protected nucleosides upon in situ silylation with tert‐butyldiphenylsilyl chloride in pyridine/ toluene to produce the corresponding 3′‐H‐phosphonothioates in good yields. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Tris(pentafluorophenyl)silyl Triflate: Synthesis and Silylation of Carbonyl Compounds
Authors: Levin Vitalij V. , Dilman Alexander D. , Belyakov Pavel A. , Korlyukov Alexander A. , Struchkova Marina I. , Tartakovsky Vladimir A.
Published: December 2004

Tris(pentafluorophenyl)silyl triflate (1) was prepared by protodesilylation of phenyl‐, allyl‐, and isopropenyloxytris(pentafluorophenyl)silyl derivatives and characterized by X‐ray crystallography. This reagent was employed for the silylation of carbonyl compounds. Aldehydes and ketones afforded the corresponding silyl enol ethers in good yields, while silylation of esters and lactones was dependent on the reaction conditions and on the substrate. A mechanism accounting for the observed phenomena is proposed. Studies of the relative reactivities of 1 and trimethylsilyl triflate are also presented. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
High‐resolution gene copy number and expression profiling of human chromosome 22 in ovarian carcinomas
Authors: Benetkiewicz Magdalena , Wang Yun , Schaner Marci , Wang Pei , Mantripragada Kiran K. , Buckley Patrick G. , Kristensen Gunnar , Børresen‐Dale Anne‐Lise , Dumanski Jan P.
Published: December 2004

Previous low‐resolution studies of chromosome 22 in ovarian carcinoma have suggested its involvement in the development of the disease. We report a high‐resolution analysis of DNA copy number and gene expression of 22q in 18 ovarian carcinomas using a 22q‐specific genomic microarray. We identified aberrations in 67% of the studied tumors, which displayed 3 distinct gene copy number profiles. The majority of the cases (11 of 18) demonstrated heterozygous terminal deletions of various sizes, the smallest of which was 3.5 Mb. The second profile, detected in 3 tumors, revealed the coexistence of heterozygous deletions and different patterns of low‐copy‐number gain that involved the proximal half of 22q. The latter finding has not been reported previously in ovarian carcinoma. One case displayed a continuous deletion encompassing the entire 22q, consistent with monosomy 22. Furthermore, we compared the results with the available data on these tumors by using cDNA microarrays to define the degree of correlation between abnormalities at the DNA level and variation in mRNA expression. By a comparison with the expression data, we were able to identify 21 deleted genes showing low mRNA levels and 12 amplified genes displaying elevated gene expression, several of which play roles in cell cycle control and the induction of apoptosis. Our results indicated significant correlation between DNA copy number aberrations and variation in mRNA expression. We also identified several regions and candidate genes on 22q that should be studied further to determine their role in the development of ovarian cancer. © 2004 Wiley‐Liss, Inc.
In vivo analysis of oligodendrocyte lineage development in postnatal FGF2 null mice
Authors: Murtie Joshua C. , Zhou Yong‐Xing , Le Tuan Q. , Armstrong Regina C.
Published: December 2004

Analysis of fibroblast growth factor 2 null (FGF2−/−) and wild‐type (FGF2+/+) mice was used to interpret the potential in vivo role of endogenous FGF2 on oligodendrocyte lineage cell (OLC) responses during oligodendrogenesis and myelination. In wild‐type mouse spinal cord, FGF2 levels increased approximately threefold between the first and second postnatal weeks, a period corresponding with the peak of oligodendrogenesis. Absence of this developmental FGF2 elevation in FGF2−/− mice eliminated the transient overproduction of oligodendrocytes that is known to occur at the peak of oligodendrogenesis in wild‐type mice. Absence of FGF2 did not affect oligodendrocyte progenitor (OP) density or proliferation, based on BrdU incorporation, and also did not alter survival, based on TUNEL analysis. To examine OLC differentiation in vivo, retrovirus encoding‐enhanced green fluorescent protein (GFP) was injected into the spinal cord to heritably label endogenous cycling cells in the white matter at postnatal day 7 and then identify the generated cells at postnatal day 28. Phenotypes of cells expressing GFP were identified by morphology and immunolabeling, using CC1 for oligodendrocytes and NG2 combined with platelet‐derived growth factor α receptor for OPs. Within the population of GFP‐labeled cells, the proportion of oligodendrocytes was higher in FGF2−/− mice, indicating that endogenous FGF2 inhibited OLC differentiation in wild‐type mice. Furthermore, in FGF2−/− mice fewer cells appeared to be generated from an initial retrovirus‐labeled cell, consistent with more frequent differentiation into post‐mitotic oligodendrocytes. This in vivo analysis demonstrates that the predominant role of endogenous FGF2 on OLCs in development is inhibition of differentiation. © 2004 Wiley‐Liss, Inc.
Freedom and controversy on campus: The holocaust questioned
Authors: Foote II Edward T.
Published: December 2004

When the student newspaper editors plan to publish an ad questioning the existence of the Holocaust, the issue “burn[s] throughout the community.” Should the president prevent the ad's publication? What principles and values should enter into his decision?
Analysis of allelic imbalances at multiple cancer‐related chromosomal loci and microsatellite instability within the same tumor using a single tumor gland from colorectal carcinomas
Authors: Sugai Tamotsu , Habano Wataru , Jiao Yu‐Fei , Suzuki Masamichi , Takagi Ryo , Otsuka Koki , Higuchi Taro , Nakamura Shin‐Ichi
Published: December 2004

Genetic changes related to colorectal carcinomas are accumulated in individual tumor glands during disease progression. Microsatellite allelic analysis of individual tumor glands from 30 colorectal carcinomas using a polymerase chain reaction (PCR) assay coupled with crypt isolation was used to detect intratumoral genetic heterogeneity, the sequence of allelic imbalances (AIs) and the microsatellite instability status of single tumor glands during neoplastic progression. In addition, the CpG islands methylated phenotype (CIMP) status was examined using a methylation‐specific PCR method. The specimens were divided into 2 groups: a pooled gland sample, which was composed of more than 50 tumor glands, and a single tumor gland sample. The latter consisted of 10 single tumor glands, which were obtained from the same tumor separately. Most colorectal carcinomas (27 of 30 tumors) examined were heterogeneous for at least one genetic alteration, with from 2 to 7 genotypically different subclones detected per tumor. In 12 of the 27 heterogeneous tumors, it was possible to define the order of genetic alterations during the tumor progression. By analyzing multiple single tumor glands within the same tumor, we found that various subclonal expansions were seen within the same tumors. Finally, the AI pattern of single tumor glands was not correlated with CIMP status. Most carcinomas appeared to have a heterogeneous composition. This may have resulted from the successful progression of one clone that had different AIs in many chromosomal regions. This suggests that knowledge of the different genotypes of multiple single tumor glands may help clarify the process of tumor progression. © 2004 Wiley‐Liss, Inc.
Cancer risk among statin users: A population‐based cohort study
Authors: Friis Søren , Poulsen Aslak H. , Johnsen Søren P. , McLaughlin Joseph K. , Fryzek Jon P. , Dalton Susanne O. , Sørensen Henrik T. , Olsen Jørgen H.
Published: December 2004

Hydroxymethylglutaryl‐CoA reductase inhibitors (statins) have been linked with potential chemopreventive effects; however, the data are conflicting. We conducted a population‐based cohort study using data from the Prescription Database of North Jutland County and the Danish Cancer Registry for the period 1989–2002. In a study population of 334,754 county residents, we compared overall and site‐specific cancer incidence among 12,251 statin users (≥2 prescriptions) with cancer incidence among nonusers and users of other lipid‐lowering drugs (n = 1,257). Statistical analyses were based on age‐standardization and Poisson regression analysis, adjusting for age, gender, calendar period and use of NSAIDs, hormone replacement therapy and cardiovascular drugs. We identified 398 cancer cases among statin users during a mean follow‐up period of 3.3 years (range 0–14 years). The age‐ and gender‐standardized incidence rates of cancer overall were 596 per 100,000 person‐years among statin users, 645 per 100,000 person‐years among nonusers and 795 per 100,000 person‐years among users of other lipid‐lowering drugs. Adjusted rate ratios for cancer overall among statin users were 0.86 (95% CI, 0.78–0.95) compared to nonusers and 0.73 (95% CI, 0.55–0.98) compared to users of other lipid‐lowering drugs. No significantly increased or decreased rate ratios were observed for any of the studied site‐specific cancers (liver, colorectum, lung, breast, prostate, female genital organs and lymphatic and haematopoietic tissue), but most estimates tended to be less than 1.0. Stratification by duration of follow‐up or number of prescriptions revealed no clear trends. In summary, individuals prescribed statins experienced a slightly reduced cancer incidence compared to population controls of nonusers and users of other lipid‐lowering drugs. Larger and longer‐term studies are needed to determine the potentially protective effect of statin use on cancer development. © 2004 Wiley‐Liss, Inc.
TAp63γ can substitute for p53 in inducing expression of the maspin tumor suppressor
Authors: Spiesbach Katja , Tannapfel Andrea , Mössner Joachim , Engeland Kurt
Published: December 2004

Maspin is a Class II tumor suppressor protein and plays a role in tumor growth by inhibiting cellular invasion and motility. It is a member of the serpin family of protease inhibitors and has been shown to reduce angiogenesis. Maspin gene expression can be upregulated by the tumor suppressor p53. We tested 7 p53‐related proteins of the p63 and p73 families for their ability to induce maspin expression. The p63 splice form TAp63γ can substitute for p53 in activating the maspin promoter. TAp63γ activates the promoter through the same consensus site as p53. In the DLD‐1 colorectal adenocarcinoma cell line, harboring a tet‐off regulated transgene, induction of TAp63γ leads to an upregulation of maspin mRNA from the chromosomal gene. With a short lag phase also maspin protein levels are elevated after induced TAp63γ expression. To assess a potential function of p63‐dependent maspin upregulation in tumors we followed expression of p53, p63 and maspin by immunohistochemistry in hepatocellular carcinomas. Two types of tumors with wild‐type or mutant p53 were assayed. Interestingly, the majority of tumors expressing only a mutated and inactive p53 protein nonetheless stain positive for maspin, whereas these tumors were positive for p63 protein expression. In summary, we show that TAp63γ can substitute for p53 in transcriptional activation of the maspin tumor suppressor gene. TAp63γ employs the same DNA recognition site for this activation as p53. We observe expression patterns of p53, p63 and maspin proteins in tumor tissue that may indicate also a function of maspin induction by p63 in tumors. © 2004 Wiley‐Liss, Inc.
Functional domains of necdin for protein–protein interaction, nuclear matrix targeting, and cell growth suppression
Authors: Taniura Hideo , Kobayashi Masakatsu , Yoshikawa Kazuaki
Published: December 2004

Necdin is a growth suppressor expressed predominantly in postmitotic neurons. The necdin gene is involved in the etiology of the genomic imprinting‐associated neurodevelopmental disorder Prader–Willi syndrome and belongs to the MAGE gene family. All the MAGE family proteins contain a large homology domain termed the MAGE homology domain (MHD). We here characterize the regions of necdin required for the protein–protein interaction, nuclear matrix targeting, and cell growth suppression. The region including entire MHD (amino acids 116–280) of necdin was required for its interaction with p53, while the regions amino acids 144–184 and 191–222 within the MHD were required for both the nuclear matrix targeting and the cell growth suppression of osteosarcoma SAOS‐2 cells. The amino‐terminal proline‐rich acidic region (amino acids 60–100) was also necessary for cell growth suppression. Tetracycline‐regulatable overexpression of necdin induced growth arrest of SAOS‐2 cells in a reversible manner, and the necdin‐overexpressing cells showed a large, flattened morphology with double nuclei. In contrast, a necdin mutant lacking amino acids 191–222 did not induce such changes. These findings suggest that different functions of necdin are mediated via its distinct domains. © 2004 Wiley‐Liss, Inc.