bluuebunny/crossref_metadata_2025 huggingface dataset:
Glutamatergic neuronal projections from the marginal layer of the rostral ventral medulla to the respiratory centers in rats
Authors: Weston Matthew C. , Stornetta Ruth L. , Guyenet Patrice G.
Published: March 2004

The marginal layer (ML) that lines the ventral surface of the medulla oblongata (VMS) contains neurons thought to contribute to central chemoreception, the process by which systemic hypercapnia activates respiration. The transmitters and connectivity of ML neurons are poorly known. The present study focuses on a group of nonserotonergic ML neurons, often located in close proximity to the entry point of penetrating blood vessels. These neurons (∼300/brain) contain vesicular glutamate transporter2 (VGLUT2) mRNA and are thus probably glutamatergic. They cluster below the caudal half of the facial motor nucleus, lateral to the serotonergic cells of the ML. The projections of serotonergic and nonserotonergic ML neurons were investigated by retrograde labeling with Fluoro‐Gold. ML VGLUT2 mRNA‐expressing neurons lack spinal projections and innervate the dorsolateral pons and the ipsilateral ventral respiratory column (VRC), most particularly, the region of the pre‐Bötzinger complex and rVRG. The latter two regions receive a very small input from ML serotonergic neurons which, instead, heavily innervate the spinal cord. In conclusion, a small region of the VMS marginal layer contains glutamatergic neurons that innervate the main respiratory centers of the medulla oblongata and pons. These glutamatergic neurons are located in a chemosensitive region of the ML and their projections are consistent with a role in central chemoreception. The serotonergic neurons of the ML, though known to be activated by CO2, probably do not contribute to central chemoreception, given that they innervate sympathetic efferents and project at best very lightly to the VRC. J. Comp. Neurol. 473:73–85, 2004. © 2004 Wiley‐Liss, Inc.
Cortical connections of the lateral mediodorsal thalamus in cynomolgus monkeys
Authors: Erickson Susan L. , Lewis David A.
Published: March 2004

The prefrontal cortex has been defined as that cortical territory that has “essential or sustaining” connections with the mediodorsal (MD) nucleus of the thalamus (Rose and Woolsey [1948] Publ Assoc Res Nerv Ment Dis 27:210–232). However, recent studies in the monkey have documented projections from MD to the more caudal, agranular regions of the frontal cortex, suggesting that the connections of MD may be characterized by a breadth of distribution and diversity of functional roles too great to be useful as a unifying and defining feature for a specific cortical territory. In this study, we placed tracer injections in the lateral divisions of MD in cynomolgus monkeys (Macaca fascicularis) to assess the relative proportions of connections devoted to diverse regions of the frontal cortex (FC). Three different patterns of label were observed in the cortex, associated with different locations within lateral MD. We have designated these as the ventrolateral MD‐arcuate FC circuit, having most label in areas 8 and 6; the caudoventral MD‐dorsomedial FC circuit, having most label in areas 24 and presupplementary motor area (SMA); and the anterodorsal MD‐anterior FC circuit, with the most label in areas 9, 46, 12, and 10. Only two of the nine cases injected in lateral MD were predominantly connected with the anterior FC. Thus, particular locales within lateral MD are connected with multiple, functionally diverse cortical regions, including several not classically recognized as “prefrontal” areas. This divergence may distinguish MD‐frontocortical and reciprocal corticothalamic pathways from the largely segregated pathways arising from the other thalamic nuclei that are interconnected with the frontal cortex, such as those from the ventrolateral nuclear group. J. Comp. Neurol. 473:107–127, 2004. © 2004 Wiley‐Liss, Inc.
Differential expression of γ‐aminobutyric acid type B receptor subunit mRNAs in the developing nervous system and receptor coupling to adenylyl cyclase in embryonic neurons
Authors: Martin Stella C. , Steiger Janine L. , Gravielle María Clara , Lyons Helen R. , Russek Shelley J. , Farb David H.
Published: March 2004

γ‐Aminobutyric acid type B receptors (GABABRs) mediate both slow inhibitory synaptic activity in the adult nervous system and motility signals for migrating embryonic cortical cells. Previous papers have described the expression of GABABRs in the adult brain, but the expression and functional significance of these gene products in the embryo are largely unknown. Here we examine GABABR expression from rat embryonic day 10 (E10) to E18 compared with adult and ask whether embryonic cortical neurons contain functional GABABR. GABABR1 transcript levels greatly exceed GABABR2 levels in the developing neural tube at E11, and olfactory bulb and striatum at E17 but equalize in most regions of adult nervous tissue, except for the glomerular and granule cell layers of the main olfactory bulb and the striatum. Consistent with expression differences, the binding affinity of GABA for GABABRs is significantly lower in adult striatum compared with cerebellum. Multiple lines of evidence from in situ hybridization, RNase protection, and real‐time PCR demonstrate that GABABR1a, GABABR1b, GABABR1h (a subunit subtype, lacking a sushi domain, that we have identified in embryonic rat brain), GABABR2, and GABABL transcript levels are not coordinately regulated. Despite the functional requirement for a heterodimer of GABABR subunits, the expression of each subunit mRNA is under independent control during embryonic development, and, by E18, GABABRs are negatively coupled to adenylyl cyclase in neocortical neurons. The presence of embryonic GABABR transcripts and protein and functional receptor coupling indicates potentially important roles for GABABRs in modulation of synaptic transmission in the developing embryonic nervous system. J. Comp. Neurol. 473:16–29, 2004. © 2004 Wiley‐Liss, Inc.
Inverse relationship between the contents of neuromelanin pigment and the vesicular monoamine transporter‐2: Human midbrain dopamine neurons
Authors: Liang Chang‐Lin , Nelson Omar , Yazdani Umar , Pasbakhsh Parichehr , German Dwight C.
Published: March 2004

The dopaminergic neurons in the ventral substantia nigra (SN) are significantly more vulnerable to degeneration in Parkinson's disease (PD) than the dopaminergic neurons in the ventral tegmental area (VTA). The ventral SN neurons also contain significantly more neuromelanin pigment than the dopaminergic neurons in the VTA. In vitro data indicate that neuromelanin pigment is formed from the excess cytosolic catecholamine that is not accumulated into synaptic vesicles by the vesicular monoamine transporter‐2 (VMAT2). By using quantitative immunohistochemical methods in human postmortem brain, we sought to examine the relative contents of VMAT2 within neurons that contain different amounts of neuromelanin pigment. The immunostaining intensity (ISI) was measured for VMAT2 and also for the rate‐limiting enzyme for the synthesis of dopamine, tyrosine hydroxylase (TH). ISI measures were taken from the ventral SN region where neurons are most vulnerable to degeneration in PD, nigrosome‐1 (N1); from the ventral SN region where cells are moderately vulnerable to degeneration in PD, the matrix (M); and from VTA neurons near the exit of the third nerve (subregion III). The data indicate that 1) subregion III neurons have significantly higher levels of VMAT2 ISI compared with N1 neurons (more than twofold) and M neurons (45%); 2) there is an inverse relationship between VMAT2 ISI and neuromelanin pigment in the N1 and III neurons; 3) there is an inverse relationship between VMAT2 ISI and the vulnerability to degeneration in PD in the N1, M, and III subregions; and 4) neurons with high VMAT2 ISI also have high TH ISI. These data support the hypothesis that midbrain dopaminergic neurons that synthesize greater amounts of dopamine have more vesicular storage capacity for action potential‐induced release of transmitter and that the ventral SN neurons accumulate the most neuromelanin pigment, in part because they have the least VMAT2 protein. J. Comp. Neurol. 473:97–106, 2004. © 2004 Wiley‐Liss, Inc.
Selective Reaction of Aminorhenium Complexes and the Formation of Cp‐N‐P Tridentate Complexes
Authors: Wang Tein‐Fu , Wang Tan‐Ching , Wen Yuh‐Sheng
Published: March 2004

Rhenium complexes containing cyclopentadienyl‐amino‐phosphanyl tridentate ligands have been prepared starting from a cyclopentadienyl‐amino bidentate complex in a controlled manner. Dehydrobromination of [η5:η1‐C5H4CH2CH2NH(CH3)Re(CO)2Br]+ (2) was carried out selectively at low temperature to give an exocyclic iminorhenium complex [η5:η1‐C5H4CH2CH2N(=CH2)Re(CO)2] (5). Selective N‐methylation provided a cationic heterocyclopropane complex 8 which reacted with various nucleophiles (tBuNH2, NaOCH3, KPPh2) to give precursors for tridentate complexes. A formal oxidation of the carbonyl ligand to a labile carbon dioxide ligand was accomplished by oxidation with peroxy acid. Intramolecular N ligand displacement furnished the Cp‐N‐P tridentate complex. The relative stability of the N, P and CO ligands was revealed when an η3‐allyl ligand was formed. The N ligand became detached from the metal rather than the P or CO ligands as the η1‐allyl was transformed to the corresponding η3‐allyl coordination mode. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Palladium Chemistry in Anhydrous HF/AsF5 Superacid Medium
Authors: Mazej Zoran , Benkič Primož , Tressaud Alain , Žemva Boris
Published: March 2004

Pd metal dissolves in anhydrous HF (aHF) acidified with AsF5 in the presence of F2 at ≈︁298 K to give a blue‐green solution from which green Pd(AsF6)2 can be isolated. The latter was also prepared by the interaction of PdF2 and AsF5 in aHF or by the reaction between PdO and F2 in aHF acidified with AsF5. Powdered Pd(AsF6)2 slowly loses AsF5 in a dynamic vacuum. It can therefore be isolated from solution at T < 253 K. Single‐crystals of Pd(AsF6)2 were prepared by solvothermal synthesis from a Pd/AsF5/F2/aHF mixture at 393 K. Pd(AsF6)2 is triclinic with a = 500.9(5), b = 538.3(5), c = 864.9(9) pm, α = 74.46(3), β = 89.97(4), γ = 62.47(2)°, V = 0.1972(3) nm3, and Z = 1, space group P$\bar 1$
(No. 2). The six‐coordinate Pd atoms (coordinated with fluorine) are well separated by isolated AsF6 units. In the 2−175 K temperature range Pd(AsF6)2 follows the Curie−Weiss law with μeff = 3.53 B.M., Tn = 8 K and θp= −13 K. Because of cation‐anion interactions, the AsF6− anions deviate from ideal Oh symmetry. The reduced symmetry can be seen in vibrational spectra, where splitting of the anion vibrational modes can be observed. The oxidation of Pd metal or PdO with F2 in neutral aHF yielded Pd2F6. No reaction was observed between Pd, PdO or Pd2F6 and AsF5 in aHF. All attempts to prepare PdFAsF6 were unsuccessful. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The Ligating Ability of Functionalised Diaminodimethylsilanes towards Zirconium(IV)
Authors: Passarelli Vincenzo , Benetollo Franco , Zanella Pierino
Published: March 2004

The functionalised diaminodimethylsilanes SiMe2[NH(CH2)nX]2 (X = NMe2, n = 2, H2L1; n = 3, H2L2; X = OMe, n = 2, H2L3; n = 3, H2L4) have been synthesised by aminolysis of SiMe2Cl2 with NH2(CH2)nX, and their ligating ability towards zirconium(IV) has been investigated. The syntheses of [ZrY2(L)] (Y = Cl, NMe2, Me; L = L1, L2, L3, L4) are reported and the solid‐state structures of some selected compounds determined by X‐ray crystallography. In addition, the solution molecular structures of all the metal derivatives have been elucidated by variable‐temperature multinuclear 1D/2D NMR spectroscopy, and the dynamics have been investigated in some selected cases. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Syntheses, Structures and Redox Properties of New Macrocyclic Triazatriolefinic Pd0 Complexes and Their Polypyrrole Modified Electrodes − Application to Heterogeneous Catalytic Suzuki Cross‐Coupling Reactions
Authors: Llobet Antoni , Masllorens Ester , Rodríguez Montserrat , Roglans Anna , Benet‐Buchholz Jordi
Published: March 2004

New triolefinic macrocyclic ligands of the type (E,E,E)‐1,6,11‐tris(arenesulfonyl)‐1,6,11‐triazacyclopentadeca‐3,8,13‐triene (aryl: a = ferrocenyl, b = 4‐pyrrol‐1‐ylphenyl, c = 4‐methylphenyl) and their Pd0 complexes (1aab, 1abb and 1bcc) have been prepared and characterized. Further structural characterization in the solid state has also been performed by means of X‐ray diffraction analysis for the complex 1bcc. The redox properties of both the ligands and their Pd complexes have been studied using cyclic voltammetric and coulombimetric techniques. In particular, complexes and ligands containing the pyrrole group do polymerize upon exposure to sufficiently positive potentials, on glassy carbon electrodes, generating highly stable modified electrodes. The new modified electrodes are efficient and selective heterogeneous catalysts for Suzuki cross‐couplings, benefiting from simple removal of the catalyst from the reaction vessel. As an example, more than 2·105 metal cycles are achieved at 65 °C in the coupling of phenylboronic acid and cinnamyl bromide. Iodoarenes and phenylboronic acid are also converted into biphenyls with relatively good conversions. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Electronic Structures and Reactivities of Corrole−Copper Complexes
Authors: Luobeznova Inna , Simkhovich Liliya , Goldberg Israel , Gross Zeev
Published: March 2004

The spectroscopic and electrochemical examination of the mononuclear copper complexes of 5,10,15‐tris(pentafluorophenyl)corrole and 5,10,15‐tris(2,6‐dichlorophenyl)corrole (1a and 2a, respectively) and of the corresponding dinuclear corrole dimers 1b and 2b reveal the existence of two almost degenerate electronic states. The lower state consists of copper(III) ions coordinated by closed‐shell corrolato trianions and the higher state is composed of copper(II) ions chelated by open‐shell corrolato dianions. The contributions from both states are evident in the molecular structure of monomeric and mononuclear 2a, which displays a distorted square‐planar coordination geometry around the metal ion and short Cu−N bond lengths typical of copper(III), together with some non‐equivalence of the Cα−Cmeso bond lengths that might reflect the open‐shell character of the macrocycle. The latter state is most likely to be responsible for the dimerization process. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Structural and Theoretical Studies of New Ruthenium‐Amidato Complexes with Phenanthroline Ligands Containing H‐Bonding Groups
Authors: Rais Daniela , Gould Ian R. , Vilar Ramón , White Andrew J. P. , Williams David J.
Published: March 2004

The syntheses, characterization and coordination chemistry of two new 1,10‐phenanthroline‐based ligands are presented here. Crystallographic studies have shown that both molecules display hydrogen‐bonding and π−π stacking interactions, generating interesting supramolecular assemblies in the solid state. The reactions of these ligands with [RuCl2(PPh3)3] have been performed and two new ruthenium‐amidato complexes have been prepared. In both cases, the presence of a pyridyl group in the ligand backbone favours the deprotonation of one of the carboxyamido moieties leading to a tridentate coordination mode of the ligands. The structural characterization of one of the ruthenium complexes is also reported. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
The First Amine‐Templated Layered Metal Selenates
Authors: Udayakumar D. , Dan Meenakshi , Rao C. N. R.
Published: March 2004

Although a few open‐framework metal sulfates and selenites have been synthesized and characterized recently, it has not been possible to prepare the corresponding selenates, probably because of the instability of the +6 oxidation state of Se in alkaline media. We have been able to synthesize, for the first time, organically templated open‐framework rare earth selenates with the general formula 0.5[C2N2H10][Ln(H2O)2(SeO4)2] (I) (Ln = La, Nd or Pr) and 0.5[C4N2H14][La(SeO4)2]·0.5H2O (II), under hydrothermal conditions in an acidic medium. Crystal data: I (Ln = La): triclinic, space group = P$\bar 1$
, Mr = 491.91, a = 7.0105(8) Å, b = 7.3772(9) Å, c = 9.526(1) Å, α = 82.014(2), β = 84.514(2), γ = 84.247(2)°, V = 483.76(1) Å3, Z = 2; II: triclinic, space group = P$\bar 1$
, Mr = 478.91, a = 5.94(2), b = 7.408(3), c = 11.048(2) Å, α = 86.899(2), β = 75.971(1), γ = 79.456(2)°, V = 463.7(2) Å3, Z = 4. Being the first report of complex layered selenates, it is likely to stimulate efforts to synthesize other novel open‐framework structures making use of the selenate ion as the building unit. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2004)
Comparative in vitro and in vivo genotoxicities of 7H‐benzo[c]fluorene, manufactured gas plant residue (MGP), and MGP fractions
Authors: Cizmas Leslie , Zhou Guo‐dong , Safe Stephen H. , McDonald Thomas J. , Zhu Li , Donnelly Kirby C.
Published: March 2004

Manufactured gas plant residue (MGP) is a complex mixture of polycyclic aromatic hydrocarbons (PAHs) that is tumorigenic in the lungs of mice. This study compared the relative genotoxicity of 7H‐benzo[c]fluorene (BC), a PAH component of MGP, with MGP and MGP fractions in order to assess the contribution of BC to the genotoxicity of MGP. An MGP sample was separated into seven fractions (F1–F7) using silica gel column chromatography with petroleum ether (PE) followed by PE:acetone (99:1 v/v, then 98:2). PAHs were quantified using gas chromatography/mass spectrometry. An aliquot of F2, the fraction with the highest BC concentration and highest weighted mutagenic activity in Salmonella typhimurium strain TA98, was further separated using silica gel thin‐layer chromatography with hexane. The first F2 subfraction, sF2‐a, was enriched in BC and coeluting compounds and contained 35,000 ppm BC and 216,109 ppm carcinogenic PAHs (cPAHs, the sum of seven PAHs categorized by the U.S. EPA as class B2 carcinogens). The second F2 subfraction, sF2‐b, contained a ninefold lower concentration of BC, with 3,900 ppm BC and 45,216 ppm cPAHs. Female ICR mice received topical application of crude MGP, crude MGP spiked with analytical‐grade BC, F2, sF2‐a, sF2‐b, or analytical‐grade BC. DNA adduct levels were analyzed by nuclease P1‐enhanced 32P‐postlabeling. In lung DNA of mice receiving 0.48 or 3.0 mg/mouse, net total RAL × 109 values were F2, 30.8 and 87.2; sF2‐a, 24.8 and 106.7; and sF2‐b, 19.6 and 151.0, respectively. Mice dosed with 0.10 mg analytical‐grade BC (the mass of BC in 3.0 mg sF2‐a) exhibited a net total RAL × 109 value of 7.03 in lung DNA. This was equal to approximately 7% of the total RAL × 109 value produced by 3.0 mg sF2‐a. Thus, although BC appears to make an appreciable contribution to pulmonary adduct formation, the results suggest that MGP components other than BC play an important role in lung DNA adduct formation following topical MGP administration. Environ. Mol. Mutagen. 43:159–168, 2004. © 2004 Wiley‐Liss, Inc.
Biofilm barriers to contain and degrade dissolved trichloroethylene
Authors: Komlos John , Cunningham Alfred B. , Camper Anne K. , Sharp Robert R.
Published: March 2004

Biologically produced subsurface barriers (i.e., biofilm barriers) are a viable technology for controlling contaminant migration from hazardous waste sites. Biofilm barriers are created through the injection of bacteria and selective growth medium into a series of wells downstream of a contaminant plume. Adequate substrate addition enables the bacteria to grow and form thick biofilms capable of uniform plugging of the subsurface. This technology has been successful in significantly reducing porous media permeability in bench‐scale and field‐scale applications. The research presented herein expands on current biofilm barrier technology by examining the feasibility of using a biofilm barrier to not only control contaminant migration through permeability reduction, but also facilitate contaminant biodegradation. The experimental scenario involved the creation of a dual‐species biofilm matrix: one organism to reduce porous media permeability through thick biofilm formation and another organism to degrade a contaminant, in this case trichloroethylene (TCE). Porous medium column experiments demonstrated that a dual‐species biofilm barrier can be created and that growth medium concentration was a very important variable in controlling simultaneous TCE degradation and permeability reduction. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 69–77, 2004
Soil lead bioavailability and in situ remediation of lead‐contaminated soils: A review
Authors: Hettiarachchi Ganga M. , Pierzynski Gary M.
Published: March 2004

The environmental risk from soil lead (Pb) is related to its bioavailability. Soil Pb bioavailability depends on the solubility of Pb solid phases and other site‐specific soil chemistry, suggesting that in situ stabilization of soil Pb can be accomplished by changing soil Pb chemistry. This paper presents a review of soil Pb bioavailability and an evaluation of in situ stabilization methods that can be used to reduce Pb bioavailability. A promising in situ approach involves the amendment of Pb‐contaminated soil with phosphorus (P) in various forms or P with other amendments. Two general categories of P are insoluble forms, such as phosphate rock or synthetic apatites, and soluble forms typically present in commercially available fertilizer products or phosphoric acid. Numerous indirect assessment techniques show marked reductions in soil Pb biovailability upon addition of P and other amendments to Pb‐contaminated soils. The techniques include physiologically based extraction tests, plant uptake of Pb, and other soil Pb extraction methods. More directly, animal feeding studies also show reductions in soil Pb biovailability. In situ stabilization of soil Pb using P and other soil amendments is an emerging technology integrating soil chemistry, agricultural practices, and engineering that is gaining public and regulatory acceptance. © 2004 American Institute of Chemical Engineers Environ Prog, 23: 78–93, 2004
Effect of duct velocity profile and buoyancy‐induced flow on efficiency of transient hydrodynamic removal of a contaminant from a cavity
Authors: Fang Lih‐chuan
Published: March 2004

This paper describes a preliminary numerical analysis of the effect of duct velocity profile and buoyancy‐induced flow generated by the heat source on hydrodynamic removal of contaminants contained in cavities. The process of fluid renewal in a cavity is modelled via a numerical solution of the Navier–Stokes equations coupled with the energy equation for transient flows. The foulant has the same density as the fluid in the duct and the duct velocity profile is considered to be Poiseuille flow and Couette flow, respectively. The results show that the change in Grashof number and duct flow velocity profile causes a dramatic difference in the observed flow patterns and cleaning efficiency. From a cleaning perspective, the results suggest that Couette flow at higher value of Grashof number becomes more effective in further purging of contaminated fluid from a cavity. Copyright © 2004 John Wiley & Sons, Ltd.
Improving the accuracy of the spatial discretization in finite‐difference electrochemical kinetic simulations, by means of the extended Numerov method
Authors: Bieniasz Lesław K.
Published: March 2004

The fourth‐order accurate, three‐point finite‐difference Numerov spatial discretization provides accurate and efficient solutions to the time‐dependent governing differential equations of electrochemical kinetics in one‐dimensional space geometry, when the equations contain first time derivatives of the solution, second spatial derivatives, and homogeneous reaction terms only. However, the original Numerov discretization is not applicable when the governing equations involve first spatial derivative terms. To overcome this limitation, an appropriately extended Numerov discretization is required. We examine the utility of one of such extensions, first described by Chawla. Relevant discrete formulae are outlined for systems of linear governing equations involving first derivative terms, and applied to five representative example models of electrochemical transient experiments. The extended Numerov discretization proves to have an accuracy and efficiency comparable to the original Numerov scheme, and its accuracy is typically up to four orders of magnitude higher, compared to the conventional, second‐order accurate spatial discretization, commonly used in electrochemistry. This results in a considerable improvement of efficiency. Therefore, the application of the extended Numerov discretization to the electrochemical kinetic simulations can be fully recommended. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1075–1083, 2004
Hydrogen bonding, solvation, and hydrolysis of cisplatin: A theoretical study
Authors: Robertazzi Arturo , Platts James A.
Published: March 2004

Density functional calculations on a range of hydrogen bonded clusters of cisplatin are reported. A systematic search of 1:1 cisplatin:water complexes reveals only three stable minima, which contain a number of common, recurring interactions, such as an NH … OH … Cl bridging mode. Expanding these clusters by adding water molecules leads to a model of the first solvation shell of cisplatin, which contains the above motifs along with several strong waterwater interactions. The strengths of such interactions are rationalized on the basis of electrostatic potentials, and quantified by use of Atoms in Molecules properties. This analysis also allows us to estimate cisplatin's position on Abraham's hydrogen bond acidity and basicity scales, indicating that cisplatin is a strong donor and acceptor of hydrogen bonds due to the dominance of hard, electrostatic interactions. The effects of this explicit solvation on the barrier to hydrolysis, and hence activation, of cisplatin are explored, indicating a slightly higher barrier than in the gas phase, leading to better agreement with experiment than either gas phase or continuum solvation calculations. © 2004 Wiley Periodicals, Inc. J Comput Chem 25: 1060–1067, 2004
Gene delivery to respiratory epithelial cells by magnetofection
Authors: Gersting Soeren W. , Schillinger Ulrike , Lausier James , Nicklaus Petra , Rudolph Carsten , Plank Christian , Reinhardt Dietrich , Rosenecker Joseph
Published: March 2004

Background

For the topical application of DNA vector complexes to the airways, specific extracellular barriers play a major role. In particular, short contact time of complexes with the cell surface caused by the mucociliary clearance hinders cellular uptake of complexes. The aim of this study was to evaluate the ability of magnetofection, a technique based on the principle of magnetic drug targeting, to overcome these barriers in comparison with conventional nonviral gene transfer methods such as lipofection and polyfection.

Methods

Experiments were carried out on permanent (16HBE14o‐) and primary airway epithelial cells (porcine and human), and native porcine airway epithelium ex vivo. Transfection efficiency and dose‐response relationship of magnetofection were examined by luciferase reporter gene expression. Sedimentation patterns and uptake of gene transfer complexes were characterized by fluorescence and electron microscopy, respectively.

Results

We show that (i) application of a magnetic field allows the magnetofectins to sediment and to enrich at the cell surface within a few minutes, (ii) magnetofection bears an improved dose‐response relationship, (iii) magnetofection enhances transfection efficiency in both, permanent and primary airway epithelial cells, and (iv) magnetofection leads to significant transgene expression at very short incubation times in an ex vivo airway epithelium organ model.

Conclusions

Magnetofection provides a potential novel method, which may overcome fundamental limitations of nonviral gene transfer to the airways. Due to the accelerated enrichment at the cell surface it may be of major interest for in vivo applications, where long‐term incubation times at the target tissue are hardly achievable. Copyright © 2004 John Wiley & Sons, Ltd.
The role of dextran conjugation in transfection mediated by dextran‐grafted polyethylenimine
Authors: Tseng Wen‐Chi , Tang Chien‐Hsiang , Fang Tsuei‐Yun
Published: March 2004

Background

Conjugation through primary amines is one of the most commonly used methods to modify polycationic vectors for gene delivery. A better understanding of the effect of the conjugation on the mechanisms of transgene expression can help design efficient polycationic vectors.

Methods

Dextran with a molecular weight of 1500 was grafted onto polyethylenimine (PEI) to produce various degrees of grafting in an effort to investigate how the conjugation affected the mechanisms of transgene expression. Flow cytometry was employed to quantitate the cellular entry of plasmid and the level of transgene expression, which were measured using ethidium monoazide labeled plasmid and green fluorescent protein (GFP), respectively. The buffering capacity of the grafted PEI was determined by titration, and the integrity of the DNA‐polymer complexes were examined by exposure to heparin.

Results

Grafting of dextran onto PEI was found to significantly diminish the cytotoxicity, buffering capacity, cellular entry, and the integrity of the DNA‐polymer complexes. The reductions enlarged as the degree of grafting increased from 0 to 1.84%; however, at an optimal degree of grafting, the dextran‐grafted PEI enhanced the percentages of GFP‐positive cells to a level 3 times and 1.3 times of those mediated by unmodified PEI for CHO and MDA‐MB‐231 cells, respectively.

Conclusions

These results demonstrated that the conjugation of dextran onto the primary amines of PEI inhibited the entry of plasmid across the cell membrane, but the change in the structures of the DNA‐polymer complexes was able to promote transgene expression when the degrees of conjugation fell below 0.64%. Copyright © 2004 John Wiley & Sons, Ltd.
Vesicular stomatitis virus glycoprotein: a transducing coat for SFV‐based RNA vectors
Authors: Dorange Fabien , Piver Eric , Bru Thierry , Collin Christine , Roingeard Philippe , Pagès Jean‐Christophe
Published: March 2004

Background

Semliki Forest virus (SFV) vectors have a great potential for the induction of protective immunity in a large number of clinical conditions including cancer. Such a potential accounts for the huge efforts made to improve the in vivo expression from SFV vectors. It is noteworthy that efficient in vivo expression strongly relies on the ability to deliver high‐titre vectors. To achieve this, the generation of recombinant SFV particles, using independent expression systems for structural SFV genes, has been proposed. However, despite several modifications in the production process, a risk of contamination with replication‐competent, or partially recombined, virus has remained.

Methods

Here, we exploit the ability of the vesicular stomatitis virus glycoprotein (VSV‐G), expressed in trans, to hijack full‐length genomic SFV RNA into secreted virus‐like particles (VLPs). To allow SFV vector mobilisation, we designed a CMV driven SFV vector in which the internal 26S promoter has been extensively mutated. With this vector, mobilisation events were monitored using the Green Fluorescent Protein (GFP). The production procedure involves a sequential transfection protocol, of plasmids expressing the VSV‐G and the SFV vector respectively.

Results

We show that the VLPs are effective for cellular delivery of SFV vectors in a broad range of human and non‐human cellular targets. Furthermore, production of VLPs is easy and allows, through concentration, the harvest of high‐titre vector.

Conclusions

The present paper describes a convenient process aimed at mobilising full length SFV vectors. A major issue to consider, while developing clinically relevant gene transfer vectors, is the risk of undesirable generation of replication competent by‐products. Importantly, as the VSV‐G gene shares no homology with the SFV genome, our VLPs offer a strong guarantee of biosafety. Copyright © 2004 John Wiley & Sons, Ltd.
Improved non‐viral transfection of glial and adult neural stem cell lines and of primary astrocytes by combining agents with complementary modes of action
Authors: Tinsley Rogan B. , Vesey Melanie J. , Barati Shahram , Rush Robert A. , Ferguson Ian A.
Published: March 2004

Background

Rational design of gene vectors for therapeutic applications requires understanding of transfection mechanisms. In this study, multiple transfection assays revealed complementary mechanisms between two commonly used transfection agents. This finding was then exploited to produce improved transfection outcomes.

Methods and results

Rat C6 glial cells, adult rat hippocampal progenitor cells and primary astrocytes were transfected using Lipofectamine (LA) or polyethylenimine (PEI), in vitro. Although LA‐ and PEI‐transfected populations expressed the same total level of transgene product, LA transfected considerably more cells than PEI (approximately 20 vs. 14%). A fluorescently labelled plasmid and time‐course analysis, involving both flow cytometry and confocal microscopy, were used to explain this apparent discrepancy. Results showed that LA delivered more plasmid DNA to the cytoplasm and achieved transgene expression in more cells than PEI. In contrast, PEI transfected fewer cells but, on average, produced more transgene product per transfected cell.

Conclusions

A comparative transfection model was developed to explain these different characteristics. According to this model, transfection is a multistage process with different transfection agents exerting their primary effect at different stages in this process. This model forecast that it should be possible to prepare a chimeric complex with a transfection efficiency that exceeded that achievable with Lipofectamine or polyethylenimine alone. This prediction was tested and shown to hold for glioma cells, primary astrocytes, and adult neural stems cells. Copyright © 2004 John Wiley & Sons, Ltd.
Adenoviral‐mediated HGF expression inhibits germ cell apoptosis in rats with cryptorchidism
Authors: Goda Kazumasa , Fujisawa Masato , Shirakawa Toshiro , Dobashi Masaki , Shiota Goshi , Zhang Zhu Jun , Gotoh Akinobu , Kamidono Sadao
Published: March 2004

Background

Prior studies have shown that the hepatocyte growth factor (HGF), as known for its multiple biological effects, possibly regulates spermatogenesis or tubulogenesis in the testis. To clarify the effect of HGF on restoration of spermatogenesis, or testicular weight, we transferred the HGF gene into the testis of the rat experimental cryptorchid model.

Methods

Replication‐deficient recombinant adenoviral vectors containing the CAG promoter driving rat HGF (pAxCAHGF) and LacZ (pAxCALacZ) were constructed. Sprague‐Dawley rats surgically induced with unilateral cryptorchidism and subsequent orchidopexy were divided into three groups: control (PBS), pAxCALacZ and pAxCAHGF by intratesticular injection. At 2 and 4 weeks after subsequent orchidopexy, testes were removed and weighed. These specimens were analyzed histopathologically, and examined for cell apoptosis. HGF expression in these specimens associated with c‐Met receptor‐mediated signal molecules was examined by reverse transcription‐polymerase chain reaction (RT‐PCR), Western blot or immunohistochemical study.

Results

Adenovirus‐mediated HGF gene transfer induced overexpression of HGF in some seminiferous epithelial cells and interstitial cells, increased the phosphorylation of ERK and Akt, and decreased numbers of apoptotic cells of germ cells. HGF transduction also significantly increased the numbers of germ cells and testicular weight by 4 weeks compared with the other control groups.

Conclusions

Adenoviral‐mediated HGF gene transfer into the testis in the cryptorchidism rats inhibited germ cell apoptosis and restored spermatogenesis. Copyright © 2004 John Wiley & Sons, Ltd.
Marked inhibition of retinal neovascularization in rats following soluble‐flt‐1 gene transfer
Authors: Rota Rossella , Riccioni Teresa , Zaccarini Marco , Lamartina Stefania , Gallo Anna Del , Fusco Angelo , Kovesdi Imre , Balestrazzi Emilio , Abeni Damiano C. , Ali Robin R. , Capogrossi Maurizio C.
Published: March 2004

Background

In mouse models of retinopathy of prematurity (ROP) inhibitors of vascular endothelial growth factor (VEGF) functions administered systemically completely block retinal neovascularization. In contrast, selective ocular VEGF depletion has achieved an approx. 50% inhibition of retinal neovascular growth. It is unclear whether a more complete inhibition of new blood vessel development can be obtained with an anti‐VEGF therapy localized to the eye. Therefore, the objective of the present study was to determine the effect of local anti‐VEGF therapy in a different animal model which closely mimics human ROP.

Methods

Rats were exposed to alternating cycles of high and low levels of oxygen for 14 days immediately after birth; thereafter, they were intravitreally injected with an adenoviral vector expressing a secreted form of the VEGF receptor flt‐1 (Ad.sflt), which acts by sequestering VEGF. Contralateral eyes were injected with the control vector carrying the reporter gene expressing β‐galactosidase (Ad.βGal).

Results

At the peak of retinal neovascular growth, i.e. post‐natal day 21 (P21), we observed up to 97.5% decrease in retinal neovascularization in animals injected with Ad.sflt. At the end of observation (P28), no significant difference in retinal vessel number was detected in both oxygen‐injured and normoxic Ad.sflt‐treated retinas compared with untreated or Ad.βGal‐treated retinas.

Conclusion

Adenoviral‐mediated sflt‐1 gene transfer induces a near‐complete inhibition of ischemia‐induced retinal neovascularization in rats without affecting pre‐existing retinal vessels. Copyright © 2004 John Wiley & Sons, Ltd.
Introduction
Authors: Chowdhury Mushtaque , Mosley Paul , Simanowitz Anton
Published: March 2004

Analysis of the poverty impacts of microfinance is almost exclusively focused on the direct impacts on microfinance clients. The Imp‐Act programme emphasizes the need to also consider the ‘wider impacts’ achieved through non‐client beneficiaries of microfinance. To fully understand and achieve the social impacts to which microfinance aspires wider impacts need to be assessed and programmes designed to achieve these outcomes. This volume introduces methodologies, in most cases developed by practitioners, which measure these wider or ‘social’ impacts and use the results as a point of departure for understanding what institutional and policy interventions are required to make them more pro‐poor. The principal wider impacts discussed are health, community governance, postwar reconstruction, labour and finance markets and, in relation to Bolivia and Indonesia, the economy as a whole. We represent research into such wider impacts as a public good which is beneficial for all microfinance institutions (MFIs)—in particular for their public relations—and for the poverty impact of the sector as a whole, but which the individual institutions typically do not have the resources to assess. This indicates a clear role for donors. Copyright © 2004 John Wiley & Sons, Ltd.
The impact of microfinance institutions in local financial markets: a case study from Kenya
Authors: Johnson Susan
Published: March 2004

This paper looks beyond the direct impact of microcredit provision on users to examine whether microfinance institutions (MFIs) have had wider impacts within the local financial markets in which they are operating. It considers the potential for both competition and demonstration effects on other financial providers. In the context of local financial markets in and around the small town of Karatina in Central Kenya, supply side information is used to investigate the key changes in provision between 1999 and 2003. The paper concludes that changing macroeconomic conditions have been the main driver increasing competition for middle and lower income clients and that few competition or demonstration effects resulting from the MFIs are in evidence. Copyright © 2004 John Wiley & Sons, Ltd.
Screening for control genes in rat global cerebral ischemia using high‐density oligonucleotide array
Authors: Kobayashi Megumi Sugahara , Takahashi Yasuo , Nagata Toshihito , Nishida Yayoi , Murata Akiko , Ishikawa Koichi , Asai Satoshi
Published: March 2004

From conventional relative gene expression analyses (Northern blotting, in situ hybridization, and RT‐PCR), it has been reported that the expression of control genes, such as glyceraldehyde‐3‐phosphate dehydrogenase (GAPDH) and β‐actin, used as references may be affected by ischemia. Therefore, we extended searching and evaluation at the mRNA level of transcripts whose expression levels were not changed by cerebral ischemia, using a high‐density oligonucleotide array and statistical analysis in a rat global cerebral ischemia and reperfusion model. We added a hyperthermic factor and localization factor to ischemia and identified transcripts with a stable expression level under conditions even more disadvantageous than ischemia only. Screening of more than 8,000 transcripts with the Rat Genome U34A array yielded 28 transcripts, which we listed and classified according to their expression level. Widely used control genes, GAPDH and β‐actin, were not included, although cyclophilin A was included. In addition, we conducted a functional classification based on gene ontology. Under the functional classification of the 28 transcripts, many genes tended to be associated with metabolism. In conclusion, use of several transcripts is recommended, such as those we identified, as references in the analysis of gene expression in pathological models of ischemia. © 2004 Wiley‐Liss, Inc.
Job demands, job resources, and their relationship with burnout and engagement: a multi‐sample study
Authors: Schaufeli Wilmar B. , Bakker Arnold B.
Published: March 2004

This study focuses on burnout and its positive antipode—engagement. A model is tested in which burnout and engagement have different predictors and different possible consequences. Structural equation modeling was used to simultaneously analyze data from four independent occupational samples (total N = 1698). Results confirm the hypothesized model indicating that: (1) burnout and engagement are negatively related, sharing between 10 per cent and 25 per cent of their variances; (2) burnout is mainly predicted by job demands but also by lack of job resources, whereas engagement is exclusively predicted by available job resources; (3) burnout is related to health problems as well as to turnover intention, whereas engagement is related only to the latter; (4) burnout mediates the relationship between job demands and health problems, whereas engagement mediates the relationship between job resources and turnover intention. The fact that burnout and engagement exhibit different patterns of possible causes and consequences implies that different intervention strategies should be used when burnout is to be reduced or engagement is to be enhanced. Copyright © 2004 John Wiley & Sons, Ltd.
Effect of water and nitrogen management on aggregate size and carbon enrichment of soil in rice‐wheat cropping system
Authors: Tripathy Rojalin , Singh Anil Kumar
Published: March 2004

A study was carried out on a silty clay loam soil (Typic Haplustept) to evaluate the effect of farmyard manure (FYM) vis‐à‐vis fertilizer and irrigation application on the soil organic C content and soil structure. The fertilizer treatments comprised of eight different combinations of N and FYM and three water regimes. The results indicated that the application of FYM and increasing N rate increased soil organic carbon (SOC) content. Addition of FYM also increased the percentage of large sized water stable aggregates (> 5 mm) and reduced the percentage of smaller size aggregates. This was reflected in an increase in the mean weight diameter (MWD) and improved soil structure. The organic carbon content in macroaggregates (> 1 mm) was greater compared to microaggregates, and it declined with decrease in size of microaggregates. This difference in organic C content between macro‐ and microaggregates was more with higher N dose and FYM treated plots. The effect of residual FYM on MWD and organic C content of the soil after wheat harvest was not significant. The effect was less in deeper layers compared to surface layers of the soil. MWD was significantly correlated with the SOC content for the top two layers.
Trace element release from forest floor can be monitored by ion exchange resin tubes
Authors: Lang Friederike , Kaupenjohann Martin
Published: March 2004

Risk assessment of heavy metal input into forest ecosystems requires information about metal fluxes from the forest floor (organic layer) into the mineral soil. Common methods for the monitoring of element fluxes are generally time‐consuming and expensive. Additionally, the reliability of the results is in part contested especially for trace elements, showing very low concentrations which are sometimes even below analytical detection limit. We used ion exchange resin tubes installed below the forest floor to determine heavy metal and As fluxes at 25 forest monitoring sites in Germany. Chloride tracer experiments and the comparison of our data with throughfall and lysimeter data, determined within the Level II monitoring network, proved the accuracy of our method. Mean trace element fluxes based on the resin method were 50 g As ha–1 yr–1, 2 g Cd ha–1 yr–1, 168 g Cu ha–1 yr–1, 176 g Ni ha–1 yr–1, and 186 g Pb ha–1 yr–1.The results show that the organic layer may change into a source of heavy metals after emission has decreased.
Effects of earthworm activity and P‐solubilizing bacteria on P availability in soil
Authors: Wan Judy H. C. , Wong Ming H.
Published: March 2004

The effects of phosphate solubilizing bacteria (Bacillus megateriumi) (PSB) and earthworms (Pheretima guillelmiandEisenia fetida) on phosphorus (P) turnover and transformation in soil were investigated in a laboratory experiment lasting for 21 days. The treatments included soil +P. guillelmi(SW1), soil +E. fetida(SW2), soil +B. megaterium(SB), soil +P. guillelmi+B. megaterium(SBW1), soil +E. fetida+B. megaterium(SBW2), and the control with sterilized soil (control) only. The results showed that the number ofB. megaterium.was enhanced in all treatments especially those with earthworms added when compared with the control. Activities of acid phosphatase (pH = 6.5) increased in all treatments, especially in the presence ofP. guillelmiwith or without PSB (64 % and 38 %, respectively). Significant increases in both inorganic P and water‐soluble P were observed in treatments involvingB.megaterium.and earthworms when compared with the control. Inoculation of both earthworms and PSB had significant effects on microbial growth, enzymatic activity, and thus enhanced the release of available P. The dual inoculation of earthworms and bacteria further accelerated P transformation. Different performances observed for the earthworm species were probably due to their different feeding habits and physiology.