bluuebunny/crossref_metadata_2025 huggingface dataset:
Base‐catalysed hydrolysis of (E)‐ and (Z)‐mevinphos
Authors: Brown Nigel P. H. , Grayson B. Terence
Published: November 2006

The rates at which (E)‐ and (Z)‐mevinphos are hydrolysed in aqueous solutions in the pH range 8.7–11.5, and in the temperature range 30–50°C, have been measured. The overall activation parameters have been calculated, and equations to allow calculation of the rates in any basic conditions are given. The complicated routes by which (E)‐ and (Z)‐mevinphos are hydrolysed to simple molecules have been deduced. The rates for the individual steps in each route have been either measured experimentally, or have been calculated through analogue simulation of all the reactions, by matching the calculated to the observed ultraviolet spectral changes during hydrolysis. It is proposed that (Z)‐2‐carboxyl‐1‐methylvinyl dimethyl phosphate is not observed as a hydrolysis product of (Z)‐mevinphos because it decomposes by an extremely fast intramolecular reaction. The reasons for the greater lability of (E)‐mevinphos are also discussed.
Penetration and insecticidal activity of diflubenzuron in Tenebrio molitor pupae
Authors: Soltani Noureddine , Delbecque Jean‐Paul , Delachambre Jean
Published: November 2006

Diflubenzuron was found to be effective on the pupae of Tenebrio molitor L. (Coleoptera, Tenebrionidae) when applied topically, by dipping, or by injection. Death occurred before or at adult ecdysis, or during the first few days after emergence. Its effectiveness decreases with increasing age of the pupa. Diflubenzuron delays adult ecdysis and decreases the longevity of normally ecdysed adults.

After diflubenzuron had been applied topically or by dipping, the compound was determined, on the pupal cuticle, in the body and on the rearing tray, by highperformance liquid chromatography. The results showed that diflubenzuron penetrated rapidly into the body and was not degraded during the pupal life. The level of incorporation of the insecticide, in dipping experiments on pupae at the same stage, varied from one individual to another. Moreover, the mean amount of insecticide incorporated was lower after dipping of older pupae than of younger pupae. It is suggested that the lower efficacy of diflubenzuron on older pupae may be caused by the decrease both in the permeability of the cuticle and in the sensitivity of the target cells.
Diastereomer‐selective resistance in Cladosporium cucumerinum to triazole‐type fungicides
Authors: Fuchs Adriaan , De Vries Frits W.
Published: November 2006

Diastereomers of triazole‐type fungicides behaved differently with respect to their fungitoxicity towards wild‐type strains of Cladosporium cucumerinum and strains resistant to ergosterol biosynthesis inhibitors. With increasing resistance to the fungicide ‘as a whole’, the difference in resistance to the two diastereomers of triadimenol became progressively smaller, whereas for the other triazole derivatives, this difference became progressively larger. The possible consequences of such phenomena for the practical use of diastereomeric fungicides are discussed.
Action of fungicidal triazoles of the diclobutrazol series on ustilago maydis
Authors: Baldwin Brian C. , Wiggins Thomas E.
Published: November 2006

Diclobutrazol [(2RS, 3RS)‐1‐(2, 4‐dichlorophenyl)‐4, 4‐dimethyl‐2‐(1,2, 4‐triazol‐1‐yl)pentan‐3‐ol] decreased the rate of growth of Ustilago maydis during the log phase. Marked changes in sterol composition were observed with a decrease in ergosterol and an increase in methyl‐sterols, indicating a block in the removal of the 14‐methyl group. The inhibition was of rapid onset (<4 h). Changes in other lipid constituents were minor and there was no build up of unsaturated fatty acids. The fungicidal activity resides in the (2R, 3R)‐isomer, which is known to be more potent in blocking a yeast 14‐demethylase enzyme than the (2S, 3S)‐isomer. This relationship held in the 4‐chlorophenyl homologues, which as a group were less fungicidal and less potent inhibitors than the 2, 4‐dichlorophenyl compounds. The evidence presented indicates that the primary lesion caused by the fungicide was a build up of membrane sterols containing extra methyl groups; this, in combination with a loss of ergosterol, is believed to prevent proper membrane ordering and thus to cause a loss of membrane function.
Structure‐activity relationships in a group of imidazole‐1‐carboxamides
Authors: Copping Leonard G. , Birchmore Richard J. , Wright Kenneth , Godson David H.
Published: November 2006

Detailed structure‐activity studies in a series of substituted imidazole‐1‐carboxamides culminated in the synthesis of N‐alkyl‐N‐phenoxyalkyl substituted compounds and, eventually, prochloraz, a compound shown to give excellent broad‐spectrum disease control in cereals. Subsequently, evidence was obtained which suggests that its mode of action is through the inhibition of ergosterol biosynthesis or, more specifically, through inhibition of sterol C‐14 demethylation.
Positive width function and energy indeterminacies in ammonia molecule
Authors: Douvropoulos Theodosios G.
Published: November 2006

A recently published methodology based on the semiclassical path integral theory was applied in a double well structure and gave the analytic form of the system's Green's function. This type of potential can describe the ammonia molecule as far as the motion of the nitrogen atom perpendicular to the hydrogen plane is discussed. Because of the fact that a double well describes a bound system and correspondingly stationary states (constructed by the symmetric and antisymmetric superposition of the eigenstates of the two unperturbed wells), it was expected that the energy spectrum would be real, in a form of doublets due to the splitting effect that takes place. However, the result was a pair of complex poles, which had a clearly positive imaginary part for each member. The present work explains the role of the imaginary parts of the complex poles as the decay rate of quantities defined as the energy indeterminacies, which are directly related to the fact that energy is not well determined in a classically forbidden region of motion. These quantities come as a function of (dκ)/dE, which is the derivative of the classical action inside the potential barrier, with respect to energy. The major contribution comes from the turning points, and then the imaginary parts are responsible, not only for the conservation of energy, but for the correct sign of time as well. In this way, a different approach for the tunneling process is adopted, in which the entry or exit of the particle from the potential barrier takes place inside a neighborhood of the turning point, as though the latter was broadened and fluctuating. The magnitude of the previously mentioned decay rate is equal to ω/π, where ω is the frequency of the classical oscillations inside one well. In contrast, the inversion frequency is generated by the part of the complex pole that is unrelated to (dκ)/dE and is much smaller in magnitude than the classical frequency, since it is given as ω/π exp(−κ). In this way, the period of the energy fluctuations is much smaller than the internal period of the system produced by the oscillating communication of the two classically allowed regions of motion. © 2006 Wiley Periodicals, Inc. Int J Quantum Chem, 2007
Sm2Se5O13: A Selenite–Diselenite according to Sm2(SeO3)(Se2O5)2
Authors: Wickleder Mathias S.
Published: November 2006

Pale yellow single crystals of Sm2(SeO3)(Se2O5)2 (monoclinic, P21/c, Z = 4, a = 1003.6(2), b = 1022.5(2), c = 1287.3(2) pm, β = 112.3(2)°) were obtained from the reaction of Sm2O3 and SeO2 at 350 °C in a sealed glass ampoule. In the crystal structure both Se2O52− and SeO32− groups connect the Sm3+ ions into layers. Between the layers the lone electron pairs of the anions are located.
Synthesis, Crystal Structure and Magnetic Properties of Na3OsO5
Authors: Mogare Kailash M. , Klein Wilhelm , Schilder Helmut , Lueken Heiko , Jansen Martin
Published: November 2006

Na3OsO5 has been synthesized by solid state reaction of Na2O2 and osmium powder under a flow of oxygen. Na3OsO5 crystallizes trigonal in space group P3121 with a = 5.5529(2) Å, c = 13.4726(8) Å, V = 359.77(3) Å3, Z = 3, 958 independent reflections, R1 = 1,97 %, wR2 = 4.27 %. The crystal structure consists of OsO5 trigonal bipyramids separated by sodium cations, and is isostructural to Na3ReO5. The osmium atoms adopt a packing analogous to ccp, where Na occupies the octahedral and tetrahedral vacancies, so the cation structure is derived from the Li3Bi structure type. Features of the synthesis of Na3OsO5 and related osmates are discussed. Na3OsO5 shows paramagnetic behaviour down to 25 K where it orders antiferromagnetically. Below 7 K a weak ferromagnetic contribution is detected. The paramagnetic region of the 5d1 system has been successfully described in the temperature range 50 – 330 K accounting for strong spin‐orbit coupling, ligand‐field potential of D3h symmetry (corresponding to the trigonal bipyramidal $\rm OsO^{3-}_{5}$ unit), and cooperative magnetic effects (molecular field parameter λMF).
Mechanism of linoleic acid hydroperoxide reaction with alkali
Authors: Gardner Harold W. , Simpson Thomas D. , Hamberg Mats
Published: November 2006

Treatment of (13S,9Z,11E)‐13‐hydroperoxy‐9,11‐octadecadienoic acid (13S‐HPODE) with strong alkali resulted in the formation of about 75% of the corresponding hydroxy acid, (13S,9Z,11E)‐13‐hydroxyl‐9,11‐octadecadienoic acid (13S‐HPODE), and the remaining 25% of products was a mixture of several oxidized fatty acids, the majority of which was formed from (9Z,11R,S,12S,R)‐13‐oxo‐11, 12‐epoxy‐9‐octadecenoic acid by Favorskii rearrangement (Gardner, H.W.,et al. (1993)Lipids 28, 487–495). In the present work, isotope experiments were completed in order to get further information about the initial steps of the alkali‐promoted decomposition of 13S‐HPODE.1. Reaction of [hydroperoxy‐18O2]13S‐HPODE with 5 M KOH resulted in the formation of [hydroxy‐18O]13S‐HPODE and [epoxy‐18O](9Z,11R,S,12S,R)‐13‐oxo‐11, 12‐epoxy‐9‐octadecenoic acid;2. treatment of a mixture of [U‐14C]13S‐HPODE and [hydroperoxy‐18O2]13S‐HPODE with KOH and analysis of the reaction product by radio‐TLC showed that 13S‐HPODE was stable under the reaction conditions and did not serve as precursor of other products;3. reaction of a mixture of [U‐14C]13‐oxo‐9,11‐octadecadienoic acid (13‐OODE) and [hydroperoxy‐18O2]13S‐HPODE with KOH resulted in the formation of [U‐14C‐epoxy‐18O](9Z,11R,S,12S,R)‐13‐oxo‐11,12‐epoxy‐9‐octadecenoic acid;4. treatment of a mixture of [hydroperoxy‐18O2] 13S‐HPODE and [carboxyl‐18O1]13S‐HPODE with KOH afforded (9Z,11R,S,12S,R)‐13‐oxo‐11,12‐epoxy‐9‐octadecenoic acid having an18O‐labeling pattern which was in agreement with its formation by intermolecular epoxidation. It was concluded that (9Z,11R,S,12S,R)‐13‐oxo‐11, 12‐epoxy‐9‐octadecenoic acid is formed from 13S‐HPODE by a sequence involving initial dehydration into the α,β‐unsaturated ketone, 13‐OODE, followed by epoxidation of the Δ11 double bond of this compound by the peroxyl anion of a second molecule of 13S‐HPODE. Rapid conversion of hydroperoxides by alkali appreared to require the presence of an α,β‐unsaturated ketone intermediate as an oxygen acceptor. This was supported by experiments with a saturated hydroperoxide, methyl 12‐hydroperoxyoctadecanoate, which was found to be much more resistant to alkali‐promoted conversion than 13S‐HPODE.
Dietary sunflower oil reduces plasma and liver triacylglycerols in fasting rats and is associated with decreased liver microsomal phosphatidate phosphohydrolase activity
Authors: Frémont Lucie , Gozzelino Marie‐Thérèse
Published: November 2006

Plasma and liver lipids were studied in male weanling rats fed diets containing moderate levels of fat (6% by weight) as sunflower oil (SF diet, rich in linoleic acid), salmon oil (SM diet, rich in long‐chain n‐3 fatty acids), or a blend of peanut and rapeseed oil (PR diet, rich in oleic acid). After nine weeks of feeding, the fasting plasma cholesterol concentrations were 49 and 24% lower in groups SM and SF, respectively, as compared to group PR. Both dietary salmon oil and sunflower oil lowered the tricylglycerol concentration of plasma and liver but, unexpectedly, the response was higher with sunflower oil. Indeed, in group SM the values were 15 and 30% lower in plasma and liver, whereas in group SF, they were 24 and 53% lower, respectively. As compared to group PR, liver triacylglycerols and microsomes contained 2.5‐ and 2.3‐fold less oleic acid, respectively, in group SF, and they were 9.2‐ and 3.2‐fold enriched in n‐3 fatty acids, respectively, in group SM. The liver triacylglycerol concentrations were correlated with changes in the microsomal Mg2+‐dependent phosphatidate phosphohydrolase activity (r=0.47,P<0.01). As oleic acid, unlike long‐chain n‐3 fatty acids, is considered to promote the triacylglycerol synthesis and secretion, our findings suggest that changes in the membrane fatty acid composition could affect the triacylglycerol content of liver and plasma. Moreover, the availability within the liver, of oleic acid, predominantly incorporated into triacylglycerols, might limit the triacylglycerol production in SF‐fed rats.
Responses of ring widths and maximum densities of Larix gmelinii to climate on contrasting north‐ and south‐facing slopes in central Siberia
Authors: Kujansuu Joni , Yasue Koh , Koike Takayoshi , Abaimov Anatoly P. , Kajimoto Takuya , Takeda Takashi , Tokumoto Morihiko , Matsuura Yojiro
Published: November 2006

An analysis was performed of the climatic responses of the radial growth of Larix gmelinii (Rupr.) Rupr. at two sites—both of which included contrasting north‐ and south‐facing slopes—in Tura, central Siberia, with the development of ring width and maximum‐density chronologies for each slope. Both residual and standard chronologies of ring widths were positively correlated with temperature from late May until mid June on all four slopes. By contrast, standard chronologies of ring widths were negatively correlated with precipitation during the winter (from October to April) and in May on the north‐facing slope at site 1 and on the south‐facing slope at site 2 respectively. The negative correlations with precipitation during the winter and in May on some of the slopes suggested that delayed snowmelt in early spring might inhibit the radial growth of L. gmelinii, and the effects of snow are likely to vary with topography. Both residual and standard chronologies of maximum densities were positively correlated with temperature in early July on all four slopes. Maximum densities were also positively correlated with precipitation during summer of the previous year on all the slopes. These suggest that no major differences exist in terms of responses of maximum density to climatic factors between the north‐ and south‐facing slopes.
Compression of the Deep Palmar Branch of the Ulnar Nerve by a Ganglion
Authors: Duggal A. , Anastakis D. J. , Salonen D. , Becker E.
Published: November 2006

A ganglion originating from the pisotriquetral joint is the most common cause of distal ulnar nerve compression. Midpalmar ganglions causing ulnar nerve compression are rare. This case describes a ganglion arising from the third carpometacarpal joint causing compression of the deep motor branch of the ulnar nerve.
Studies on N‐nitroso bile acid amides in relation to their possible role in gastrointestinal cancer
Authors: Dayal Bishambar , Ertel Norman H.
Published: November 2006

Cancers of the gastrointestinal tract account for a large proportion of neoplastic diseases which afflict humans. The etiology of gastrointestinal cancer has been attributed in part to exogenous carcinogens, such as food substances and environmental pollutants. Recent hypotheses suggest that carcinogens may arise endogenously. Evidence suggests that some bile acids and their isomeric metabolites may be involved in the pathogenesis of colon cancer. However, the mechanism responsible for their cancer‐promoting effect is not clear. We and others propose that one mechanism for the mitogenic effects of bile acids may be N‐nitrosation of their glycine and taurine amides; human gastric aspirates do contain small quantities of N‐nitroso compounds of other substrates. Many foods contain nitrites and nitrates, which can react with bile acid amides to form N‐nitroso derivatives. Our recent studies demonstrated the potential for N‐nitroso conjugate formation from ursodeoxycholic acid, a 7β‐epimer of chenodeoxycholic acid used as a drug Actigall® to dissolve gallstones. The N‐nitroso derivative of this compound, a direct‐acting carcinogen, has a long half‐life and, once nitrosated, is stable enough to survive passage through the gastrointestinal tract. We describe the synthesis of N‐nitrosated derivatives of various bile acid conjugates and mechanisms of decomposition of (Z)‐ and (E)‐bile acid diazoates. Studies of the effects of enzymes such as cholylglycine hydrolase on the N‐nitroso bile acid conjugates and their reaction with DNA are also described. These studies may have important implications in the interplay of diet with endogenous substrates in the etiology of cancers of the stomach, liver, and colon.
Desert dust aerosol columnar properties over ocean and continental Africa from Lidar in‐Space Technology Experiment (LITE) and Meteosat synergy
Authors: Berthier S. , Chazette P. , Couvert P. , Pelon J. , Dulac F. , Thieuleux F. , Moulin C. , Pain T.
Published: November 2006

The new generation of spaceborne backscatter lidar systems, prefigured by the Lidar in‐Space Technology Experiment (LITE) mission in September 1994, will give new insight on the vertical distribution of both aerosols and clouds in the atmosphere. This is especially of importance for aerosols over land, where retrievals from passive sensors are known to be more difficult because of the surface contribution. Here we analyze mineral dust aerosol transport events through a new approach coupling the active LITE and passive Meteosat‐5 spaceborne observations. The Meteosat‐derived aerosol optical thickness at 550 nm is shown to be a good boundary condition for the lidar inversion in order to retrieve both the aerosol backscatter to extinction ratio (BER) and the aerosol extinction vertical profile above the Tropical Atlantic Ocean (TAO) and the Mediterranean Sea. Sensitivity tests indicate that the aerosol scattering coefficient is retrieved within a 20% relative uncertainty. Air mass trajectories allow us to further retrieve the vertical profile of aerosol optical properties over the continent in the Saharan Heat Low (SHL) region using the BER determined over the ocean. Results confirm a large dispersion of the BER which is not attributed to errors in the method. This shows the need to account for such dispersion in the retrieval of dust aerosol optical thickness and aerosol impact on the earth radiative budget. The coupling between LITE and Meteosat‐5 made here is shown to be interesting for an improvement of the direct dust aerosol forcing, and results should be improved by the CALIOP‐MODIS synergy.
Behavior of debris from laser-produced plasma for extreme ultraviolet light source measured by laser imaging technique
Authors: Tanaka Hiroki , Hashimoto Yuki , Tamaru Kouji , Takahashi Akihiko , Okada Tatsuo
Published: November 2006

The behavior of debris generated from a laser-produced plasma (LPP) for the extreme ultraviolet light source at 13.5nm has been studied using a laser induced fluorescence (LIF) imaging system. Tin (Sn) LPPs were produced by irradiating a flat Sn plate and Sn thin films perpendicularly with a Nd:YAG laser beam. When a thin Sn film was used as a target material, the depletion of the Sn atoms was clearly observed along the Nd:YAG laser beam. The LIF system was also used for visualizing the sputtering process of a mirror substrate by the fast ions generated from the plasma.
Increased electron mobility in n-type Si-doped AlN by reducing dislocation density
Authors: Taniyasu Yoshitaka , Kasu Makoto , Makimoto Toshiki
Published: November 2006

For n-type Si-doped AlN with a low Si doping concentration of 3×1017cm−2, a high room-temperature electron mobility of 426cm2V−1s−1 was achieved, and at 220K the mobility reached 730cm2V−1s−1, the highest value ever reported for AlN. At Si doping concentrations lower than 1018cm−3, dislocation scattering is the most dominant scattering mechanism, and the mobility can therefore be increased significantly by reducing the dislocation density.
Isolation and differential expression of β-1,3-glucanase messenger RNAs, SrGLU3 and SrGLU4, following inoculation of Sesbania rostrata
Authors: Liu Chi-Te , Aono Toshihiro , Kinoshita Misako , Miwa Hiroki , Iki Taichiro , Lee Kyung-Bum , Oyaizu Hiroshi
Published: November 2006

We report here the isolation and characterisation of two new β-1,3-glucanase cDNAs, SrGLU3 and SrGLU4, from a tropical legume Sesbania rostrata Bremek. & Oberm., which form N2-fixing nodules on the stem after infection by Azorhizobium caulinodans. SrGLU3 was characterised as being grouped in a branch with tobacco class I β-1,3-glucanases, where the isoforms were reported to be induced by either pathogen infection or ethylene treatment. SrGLU4 was characterised as separate from other classes, and we propose this new branch as a new class (Class VI). The SrGLU3 gene was constitutively expressed in normal stem nodules induced by the wild type strain of A. caulinodans (ORS571), and also even in immature stem nodules induced by a mutant (ORS571-C1), which could not form mature stem-nodules. In contrast, the transcript accumulation of SrGLU4 was hardly detectable in immature nodules inoculated by the ORS571-C1 mutant. We suggest that S. rostrata makes use of SrGLU4 to discriminate between symbionts and non-symbionts (mutants) in developing nodules. We propose the SrGLU4 gene as a new nodulin during nodulation.
Iron deficiency induces sulfate uptake and modulates redistribution of reduced sulfur pool in barley plants
Authors: Astolfi Stefania , Zuchi Sabrina , Cesco Stefano , Sanità di Toppi Luigi , Pirazzi Daniela , Badiani Maurizio , Varanini Zeno , Pinton Roberto
Published: November 2006

We studied the possibility that the sulfur (S) assimilatory pathway might be modulated by iron (Fe) starvation in barley, as a consequence of plant requirement for an adequate amount of reduced S to maintain methionine and, in turn, phytosiderophore biosynthesis. Barley seedlings were grown with or without 100 µm FeIII–EDTA, at three S levels in the nutrient solution (S2 = 1200, S1 = 60, and S0 = 0 µm sulfate) in order to reproduce conditions of optimal supply, latent and severe deficiency, respectively. Fe deprivation increased root cysteine content irrespective of the S supply. However, this increase was not associated with either higher rates of 35SO42– uptake or increased expression of the gene for the high-affinity sulfate transporter, HvST1, and these roots failed to increase their activities of ATP sulfurylase (ATPS) and O-acetylserine(thiol) lyase (OASTL). We observed a significant increase in 35SO42– uptake rate (+76%) only in Fe-deficient S1 plants and we found an increase in root ATPS activity only in S0 plants. We observed an increase of ATPS enzyme activity in leaves of S1 and S2 plants, most likely suggesting increased S assimilation followed by translocation of thiols (Cys) to the root. Taken together, our results suggest that Fe deficiency affects the partitioning from the shoot to the root of the reduced S pool within the plant and can affect SO42– uptake under limited S supply.
The Vacuolar Transporter Chaperone (VTC) Complex Is Required for Microautophagy
Authors: Uttenweiler Andreas , Schwarz Heinz , Neumann Heinz , Mayer Andreas
Published: November 2006

Microautophagy involves direct invagination and fission of the vacuolar/lysosomal membrane under nutrient limitation. This occurs by an autophagic tube, a specialized vacuolar membrane invagination that pinches off vesicles into the vacuolar lumen. In this study we have identified the VTC (vacuolar transporter chaperone) complex as required for microautophagy. The VTC complex is present on the ER and vacuoles and at the cell periphery. On induction of autophagy by nutrient limitation the VTC complex is recruited to and concentrated on vacuoles. The VTC complex is inhomogeneously distributed within the vacuolar membranes, showing an enrichment on autophagic tubes. Deletion of the VTC complex blocks microautophagic uptake into vacuoles. The mutants still form autophagic tubes but the production of microautophagic vesicles from their tips is impaired. In line with this, affinity-purified antibodies to the Vtc proteins inhibit microautophagic uptake in a reconstituted system in vitro. Our data suggest that the VTC complex is an important constituent of autophagic tubes and that it is required for scission of microautophagic vesicles from these tubes.
Insulin-like signaling and the neural circuit for integrative behavior in C. elegans
Authors: Kodama Eiji , Kuhara Atsushi , Mohri-Shiomi Akiko , Kimura Koutarou D. , Okumura Masatoshi , Tomioka Masahiro , Iino Yuichi , Mori Ikue
Published: November 2006

Caenorhabditis elegans exhibits a food-associated behavior that is modulated by the past cultivation temperature. Mutations in INS-1, the homolog of human insulin, caused the defect in this integrative behavior. Mutations in DAF-2/insulin receptor and AGE-1/phosphatidylinositol 3 (PI-3)-kinase partially suppressed the defect of ins-1 mutants, and a mutation in DAF-16, a forkhead-type transcriptional factor, caused a weak defect. In addition, mutations in the secretory protein HEN-1 showed synergistic effects with INS-1. Expression of AGE-1 in any of the three interneurons, AIY, AIZ, or RIA, rescued the defect characteristic of age-1 mutants. Calcium imaging revealed that starvation induced INS-1-mediated down-regulation of AIZ activity. Our results suggest that INS-1, in cooperation with HEN-1, antagonizes the DAF-2 insulin-like signaling pathway to modulate interneuron activity required for food-associated integrative behavior.
Hedgehog signaling and the retina: insights into the mechanisms controlling the proliferative properties of neural precursors
Authors: Locker Morgane , Agathocleous Michalis , Amato Marcos A. , Parain Karine , Harris William A. , Perron Muriel
Published: November 2006

Hedgehog signaling has been linked to cell proliferation in a variety of systems; however, its effects on the cell cycle have not been closely studied. In the vertebrate retina, Hedgehog's effects are controversial, with some reports emphasizing increased proliferation and others pointing to a role in cell cycle exit. Here we demonstrate a novel role for Hedgehog signaling in speeding up the cell cycle in the developing retina by reducing the length of G1 and G2 phases. These fast cycling cells tend to exit the cell cycle early. Conversely, retinal progenitors with blocked Hedgehog signaling cycle more slowly, with longer G1 and G2 phases, and remain in the cell cycle longer. Hedgehog may modulate cell cycle kinetics through activation of the key cell cycle activators cyclin D1, cyclin A2, cyclin B1, and cdc25C. These findings support a role for Hedgehog in regulating the conversion from slow cycling stem cells to fast cycling transient amplifying progenitors that are closer to cell cycle exit.
ABO blood group but not haemostasis genetic polymorphisms significantly influence thrombotic risk: a study of 180 homozygotes for the Factor V Leiden mutation
Authors:   Procare‐GEHT Group
Published: November 2006

Limited data exist on the impact of additional genetic risk factors on the clinical manifestations of factor (F) V Leiden homozygotes. A retrospective multi‐centre cohort study was performed to assess the role of the FII G20210A gene mutation, the protein C (PC) promoter CG haplotype, the combination of two PC polymorphisms (A‐1641G, C‐1654T), the FXIII Val34Leu polymorphism, two thrombin‐activatable fibrinolysis inhibitor polymorphisms (Thr325Ile, Ala147Thr), two plasminogen activator inhibitor‐1 polymorphisms (‐675 4G/5G, A‐844G), the methylene‐tetrahydrofolate reductase (MTHFR) C677T polymorphism and the ABO blood group on the thrombotic phenotype in FV Leiden homozygotes. 127 subjects with venous thrombosis and 53 asymptomatic subjects were analysed. The T allele of MTHFR C677T was more frequent in symptomatic subjects than in asymptomatic ones (68% vs. 45%, P = 0·02; odds ratio (OR) 2·8, 95% CI 1·3–5·8, after adjustment for potential confounders). For the other polymorphisms, no difference was observed between symptomatic and asymptomatic subjects. The non‐O blood group was more frequent among symptomatic carriers (84% vs. 57%, P = 0·0002; OR 4·1, 95% CI 1·7–9·7). In conclusion, except for the ABO blood group, none of the polymorphisms studied contribute strongly to the thrombotic risk in FV Leiden homozygotes.
Erythropoietin treatment in advanced multiple myeloma is associated with improved immunological functions: could it be beneficial in early disease?
Authors: Prutchi‐Sagiv Sara , Golishevsky Natalia , Oster Howard S. , Katz Odelia , Cohen Amos , Naparstek Elizabeth , Neumann Drorit , Mittelman Moshe
Published: November 2006

Erythropoietin (Epo) is the main growth regulator of red blood cells, and recombinant human erythropoietin (rHuEpo) is thus used in clinical practice for the treatment of anaemia, primarily in kidney disease and cancer. rHuEpo treatment was found to be associated with prolonged survival of multiple myeloma (MM) patients. This clinical observation was then supported by studies on murine myeloma models. It thus appeared that rHuEpo had an anti‐myeloma effect, causally related to an immunomodulatory function of rHuEpo. The present study investigated whether rHuEpo‐treated MM patients acquire improved immunological functions. Treatment with rHuEpo, prescribed for anaemia that occurs in advanced disease, was associated with effects on a variety of immunological parameters and functions. This was expressed in an actual normalisation of the CD4:CD8 cell ratio, enhanced T cell phytohaemagglutinin‐mediated activation and proliferation potential, T cell expression of the costimulatory CD28 and inhibitory CTLA‐4 molecules, as well as reduced interleukin‐6 serum values to normal levels. Furthermore, it was demonstrated that immunological abnormalities manifest in patients even in the early stages of MM. Our findings thus suggest that rHuEpo treatment might be effective in the early stages of MM, before anaemia develops. It is expected that this would boost the immune system, consequently achieving an anti‐myeloma function; affecting disease progression and improving the prognosis.
Pulmonary disposition of tilmicosin in foals and in vitro activity against Rhodococcus equi and other common equine bacterial pathogens
Authors: WOMBLE A. , GIGUÈRE S. , MURTHY Y. V. S. N. , COX C. , OBARE E.
Published: November 2006

The objectives of this study were to determine the serum and pulmonary disposition of tilmicosin in foals and to investigate the in vitro activity of the drug against Rhodococcus equi and other common bacterial pathogens of horses. A single dose of a new fatty acid salt formulation of tilmicosin (10 mg/kg of body weight) was administered to seven healthy 5‐ to 8‐week‐old foals by the intramuscular route. Concentrations of tilmicosin were measured in serum, lung tissue, pulmonary epithelial lining fluid (PELF), bronchoalveolar lavage (BAL) cells, and blood neutrophils. Mean peak tilmicosin concentrations were significantly different between sampling sites with highest concentrations measured in blood neutrophils (66.01 ± 15.97 μg/mL) followed by BAL cells (20.1 ± 5.1 μg/mL), PELF (2.91 ± 1.15 μg/mL), lung tissue (1.90 ± 0.65 μg/mL), and serum (0.19 ± 0.09 μg/mL). Harmonic mean terminal half‐life in lung tissue (193.3 h) was significantly longer than that of PELF (73.3 h), bronchoalveolar cells (62.2 h), neutrophils (47.9 h), and serum (18.4 h). The MIC90 of 56 R. equi isolates was 32 μg/mL. Tilmicosin was active in vitro against most streptococci, Staphylococcus spp., Actinobacillus spp., and Pasteurella spp. The drug was not active against Enterococcus spp., Pseudomonas spp., and Enterobacteriaceae.
Protein phosphorylation in plant mitochondria
Authors: Juszczuk Izabela M. , Bykova Natalia V. , Møller Ian M.
Published: November 2006

Reversible phosphorylation of proteins is one of the most common regulatory mechanisms in eukaryotic cells and it can affect virtually any property of a protein. We predict that plant mitochondria possess 50–200 protein kinases (PKs), at least as many target proteins and 10–30 protein phosphatases although all will not be expressed at the same time in the same cell type or tissue. Presently available high‐throughput methods for the identification of phosphoproteins and their phosphorylation sites are first reviewed and a number of useful databases listed. We then discuss the known phosphoproteins, PKs and phosphatases in plant mitochondria and compare with yeast and mammalian mitochondria. Three case stories—respiratory chain complex I, pyruvate dehydrogenase and formate dehydrogenase—are briefly considered before a final treatment of mitochondrial protein phosphorylation in intracellular signal transduction and programmed cell death.
Disturbance and recovery of microbial community structure and function following Hurricane Frances
Authors: Yannarell Anthony C. , Steppe Timothy F. , Paerl Hans W.
Published: November 2006

Disturbance and recovery influence microbial community structure and ecosystem functions in most natural environments. This study from a hypersaline Bahamian lagoon details the response of a benthic cyanobacterial mat to disturbance by Hurricane Frances, a category‐4 storm. Clone libraries of cyanobacterial small subunit r‐RNA genes and nitrogenase genes revealed significant shifts in cyanobacterial and diazotroph community composition following the hurricane. Post‐hurricane clone libraries were dominated by sequences that had been rare in pre‐hurricane communities. In spite of this dominance shift, re‐colonizing mat communities performed nitrogen fixation and photosynthesis at rates within the normal range of variation measured in the mat at similar salinities. There was a tendency for nitrogen fixation rates from mats re‐colonizing sites with hurricane‐related sand deposition to be higher than those from mats re‐colonizing sites without significant sand deposition. This suggests that the altered communities responded to a carbon : nitrogen imbalance that was particularly pronounced in areas subjected to disturbance by sand burial. The post‐hurricane dominance of organisms that had been previously rare suggests that pre‐hurricane diversity and functional redundancy contributed to the rapid recovery of ecosystem function in the post‐disturbance environment.
First‐line gemcitabine and carboplatin in advanced ovarian carcinoma: a phase II study
Authors: Tay SK , Ilanchadran A , Tan TY
Published: November 2006

Objectives  To evaluate tumour response rate and toxicities of gemcitabine and carboplatin in chemonaive subjects with advanced epithelial ovarian cancer.

Design  A phase II study.

Setting  Gynaecologic oncologic unit.

Population  Twenty chemonaive International Federation of Gynecology and Obstetrics (FIGO) stage IIIc and stage IV subjects with ovarian cancer.

Main outcome measures  Tumour response, disease free and overall survival and toxicity.

Methods Intravenous gemcitabine 1000 mg/m2 on day 1 and day 8 and carboplatin at area under centre (AUC) = 5 on day 1 were administered three weekly for six cycles. Subjects who received more than three cycles of chemotherapy were eligible for assessment of tumour response, while all the cycles of chemotherapy were assessed for toxicities.

Results  The mean age of the subjects was 57.3 years, and the median follow up was 38.7 months. Of the 18 eligible subjects analysed, 11 (61.1%) showed a complete clinical response, and the overall response rate was 83.3% (15/18). The median overall survival was 29.2 [95% (confidence interval) CI 22.8–35.6] months, and the median progression‐free survival was 11.6 (95% CI 4.7–18.5) months. WHO grade 3 anaemia, neutropenia and thrombocytopenia was 7.6, 9.5 and 0%, respectively, on day 8, and 15.5, 12.2 and 15.5%, respectively, on day 15. Two subjects required a total of three hospital admissions for neutropenic sepsis, and two required five hospital admissions for platelet transfusion for severe thrombocytopenia.

Conclusion  Chemonaive advanced ovarian cancer showed a high response rate to combined gemcitabine and carboplatin chemotherapy. The subjects developed moderate adverse reactions. Phase III study to evaluate the role of combined gemcitabine and carboplatin as first‐line chemotherapy in ovarian cancer is warranted.
Maternal hyperhomocysteinaemia is a risk factor for congenital heart disease
Authors: Verkleij‐Hagoort AC , Verlinde M , Ursem NTC , Lindemans J , Helbing WA , Ottenkamp J , Siebel FMH , Gittenberger‐de Groot AC , De Jonge R , Bartelings MM , Steegers EAP , Steegers‐Theunissen RPM
Published: November 2006

Objective  To investigate the inter‐relation between mother and infant homocysteine, folate and vitamin B12 status and the risk of a child with congenital heart disease (CHD).

Design  Case–control study.

Setting  Erasmus MC, University Medical Centre, Rotterdam, the Netherlands.

Population  Participants were 149 case‐mothers and their children with CHD (n= 151) and 183 control‐mothers with their children (n= 175).

Methods  Approximately 17 months after the index‐pregnancy maternal fasting, children’s random venous blood samples were drawn to measure plasma total homocysteine, serum and red blood cell (RBC) folate, and serum vitamin B12 concentrations. Data were compared between cases and controls using the Mann–Whitney U test. The biochemical parameters were dichotomised according to the cutoff value of the 10th percentile of vitamin concentrations and the 90th percentile of homocysteine concentrations based on control data. Risk estimates for the association between CHD and the biochemical parameters were estimated in a logistic regression model.

Main outcome measures  Medians (minimum–maximum) and odds ratios (OR) (95% confidence intervals [CI]).

Results  The OR (95% CI) of having a child with CHD was 2.9 (1.4–6.0) for maternal hyperhomocysteinaemia (>14.3 μmol/l). This finding is substantiated by a significant concentration‐dependent risk (Ptrend= 0.004). Hyperhomocysteinaemic case‐mothers showed significantly lower serum folate and vitamin B12 concentrations than normohomocysteinaemic case‐mothers. Serum and RBC folate concentrations were significantly higher in case‐children than that in control‐children.

Conclusions  Maternal hyperhomocysteinaemia is associated with an increased risk of CHD, partially due to low folate and vitamin B12 status. The folate status of children warrants further investigation.
Haematopoietic stem cells and endothelial progenitor cells in healthy men: effect of aging and training
Authors: Thijssen Dick H. J. , Vos Joost B. , Verseyden Caroline , Van Zonneveld Anton Jan , Smits Paul , Sweep Fred C. G. J. , Hopman Maria T. E. , De Boer Hetty C.
Published: November 2006

The number of hematopoietic stem cells (HSC) and endothelial progenitor cells (EPC) is thought to be a marker for neovascularization and vascular repair. Because physical inactivity and aging are risk factors for cardiovascular diseases, these factors may influence the numbers of HSCs and EPCs. Therefore, we examined baseline and exercise‐induced levels of HSCs and EPCs in sedentary and trained young and older men. To study the role of aging in eight sedentary young (19–28 years) and eight sedentary older men (67–76 years), baseline and acute exercise‐induced numbers of HSCs (CD34+‐cells) and EPCs (CD34+/VEGFR‐2+‐cells) were quantified by fluorescence‐activated cell sorter (FACS) analysis. To examine the effect of chronic training, eight age‐matched trained young men (18–28 years) were compared with sedentary young men, whereas older men performed an 8‐week endurance training. Older men showed significantly lower baseline and exercise‐induced levels of HSCs/EPCs than the young men (P < 0.05). In young and older men, acute exercise significantly increased HSCs (P < 0.01), but not EPCs. The absolute increase in numbers of HSCs was attenuated in older men (P = 0.03). Apart from the lower baseline numbers of EPCs after chronic training in older men, training status did not alter baseline or exercise‐induced levels of HSCs/EPCs in young and older men. We concluded that advancing age results in lower circulating numbers of HSCs and EPCs and attenuates the acute exercise‐induced increase in HSCs. Interestingly, in young as well as in older men chronic endurance training does not affect baseline and exercise‐induced numbers of HSCs and EPCs.
How old are you now?
Authors: Ellison Peter T.
Published: November 2006

Cherkas et al. provide a new, biological approach to a classic problem in anthropology – the estimation of age.
SECONDARY MORTGAGE MARKET PURCHASE COMMITMENT YIELDS
Authors: Heuson Andrea J. , Schwartz Adam , Slawson V. Carlos
Published: November 2006

We provide empirical evidence that quoted secondary market mortgage yields conform to the predictions of option theory. We compare Fannie Mae and Freddie Mac origination yields offered in the secondary market from 1985 to 2003 with the predictions of a two‐state binomial mortgage option valuation model. Our two‐state approach considers a mean‐reverting interest rate process as well as a stochastic housing price. Using predictions from option simulations, we find strong links between market practice and mortgage option prepayment and default factors over time. We also find cross‐sectional differences that are consistent with the institutional structure of the markets.
PRESIDENTIAL ELECTION UNCERTAINTY AND COMMON STOCK RETURNS IN THE UNITED STATES
Authors: Li Jinliang , Born Jeffery A.
Published: November 2006

There is substantial evidence on the influence of political outcomes on the business cycle and stock market. We further hypothesize that uncertainty about the outcome of a U.S. presidential election should be reflected in pre‐election common stock returns. Prior research pools returns based on the party of the winning candidate, assuming that the outcome of the election is known a priori. We use candidate preference (i.e., polling) data to construct a measure of election uncertainty. We find that if the election does not have a candidate with a dominant lead, stock market volatility (risk) and average returns rise.
Judicial Beginnings: The Supreme Court in the 1790s
Authors: Frankel Robert P.
Published: November 2006

There has long been a tendency to mark the beginning of the Supreme Court's history with the appointment of John Marshall as chief justice in 1801. But as the volumes of The Documentary History of the Supreme Court of the United States, 1789–1800 have exhibited, the first decade of the Court's life deserves significant attention. In the 1790s the Court asserted its autonomy, played an important role in setting the federal‐state balance, and, prior to Marbury v. Madison, exercised the authority of judicial review. The justices who sat on the Court in its first decade essentially shared the views of the two presidents who appointed them, George Washington and John Adams, but made it clear that the judiciary did not exist to serve either the executive or the legislature.
Quantitative Analysis of Representative Proteome Components and Clustering of Helicobacter pylori Clinical Strains
Authors: Park Jeong‐Won , Song Jae‐Young , Lee Seung‐Gyu , Jun Jin‐Su , Park Jeong‐Uck , Chung Mi‐Ja , Ju Jung‐Soo , Nizamutdinov Damir , Chang Myung‐Woong , Youn Hee‐Shang , Kang Hyung‐Lyun , Baik Seung‐Chul , Lee Woo‐Kon , Cho Myung‐Je , Rhee Kwang‐Ho
Published: November 2006

Background:  Several Helicobacter pylori proteins have been reported to be associated with severe symptoms of gastric disease. However, expression levels of most of these disease‐associated proteins require further evaluation in order to clarify their relationships with gastric disease patterns. Representative proteome components of 71 clinical isolates of H. pylori were analyzed quantitatively to determine whether the protein expression levels were associated with gastric diseases and to cluster clinical isolates.

Methods:  After two‐dimensional electrophoresis (2‐DE) of H. pylori isolates, spot intensities were analyzed using pdquest 2‐D Gel Analysis Software. The intensities of 10 representative protein spots, identified by peptide fingerprinting using matrix assisted laser desorption ionization‐time of flight mass spectrometry (MALDI‐TOF‐MS) or peptide sequencing using quadrupole TOF MS, were subjected to the nonparametric Mann–Whitney test and hierarchical agglomerative cluster analysis. The relationship between clusters and gastric diseases was analyzed by the chi‐squared test.

Results:  Although the spot intensities of the 10 representative proteins were highly variable within each gastric disease group, the expression levels of CagA, UreB, GroEL, EF‐Tu, EF‐P, TagD, and FldA showed some significant differences among the gastric disease patterns. On the basis of the 10 target protein intensities, hierarchical agglomerative cluster analysis generated a dendrogram with clusters indicative of chronic gastritis/gastric cancers and gastric/duodenal ulcers.

Conclusion:  These results indicated that quantitative analysis of proteome components is a feasible method for examining disease‐associated proteins and clustering clinical strains of H. pylori.
2‐Week Triple Therapy for Helicobacter pylori Infection is Better Than 1‐Week in Clinical Practice: a Large Prospective Single‐Center Randomized Study
Authors: Paoluzi Paolo , Iacopini Federico , Crispino Pietro , Nardi Francesco , Bella Antonino , Rivera Margherita , Rossi Pina , Gurnari Maurizio , Caracciolo Francesco , Zippi Maddalena , Pica Roberta
Published: November 2006

Background:  Proton pump inhibitor (PPI)‐based triple therapies are considered the standard regimens for Helicobacter pylori eradication, but the optimal duration of these regimens is still controversial. The aim of this study was to compare the efficacy of 1‐week versus 2‐week triple therapies in H. pylori‐positive patients.

Materials and Methods:  A total of 486 consecutive H. pylori‐positive patients were randomized to receive omeprazole, 20 mg b.i.d., clarithromycin 500 mg b.i.d., and either amoxicillin 1 g b.i.d. or metronidazole 500 mg b.i.d. for 1 or 2 weeks. Upper gastrointestinal endoscopy and histology were performed at entry and 2 months after the end of therapy. H. pylori status was defined according to histology and urea breath test.

Results:  At intention‐to‐treat analysis, 2‐week therapy with omeprazole, amoxicillin, and clarithromycin achieved a significantly higher eradication rate than 1‐ or 2‐week regimens with metronidazole (70% versus 52%, p = .003, versus 56%, p < .01) and the same therapy for 1‐week (70% versus 57%, p = .05). At per‐protocol analysis, 2‐week therapy with omeprazole, amoxicillin, and clarithromycin showed a significantly higher eradication rate than 1‐week of amoxicillin and metronidazole (77% versus 62%; p = .03) but no difference with 1‐week same regimen (66%) or 2‐week metronidazole and clarithromycin regimen (72%). Compliance and tolerability were good for all regimens.

Conclusions:  Two‐week therapies, independently of antibiotic combination, lead to a significant increase of H. pylori eradication rate compared to 1‐week therapies, with same compliance and tolerability, even if, taking account of low‐eradication rates, one must question whether the triple therapy should still be used.