bluuebunny/crossref_metadata_2025 huggingface dataset:
Umsetzungen von Ferrocenol und 1,1′‐Ferrocendiol mit Cyclotriphosphazenen, P3N3F6 und P3N3Cl6
Authors: Herberhold Max , Hofmann Albrecht , Milius Wolfgang
Published: December 2004

Die Hexahalogen‐cyclotriphosphazene, P3N3X6 (X  F (1 a), Cl (1 b)), reagieren mit Ferrocenol, FcOH, im Molverhältnis 1 : 1 unter Bildung der Ferrocenoxy‐Derivate FcO[P3N3X5] (X  F (3 a), Cl (3 b)); der tetramere Ring P4N4Cl8 (2 b) bildet in analoger Weise FcO[P4N4Cl7] (4 b). 1,1′‐Ferrocendiol, fc(OH)2, setzt sich mit P3N3X6 im Molverhältnis 1 : 1 zu fcO2[P3N3X4] (X  F (5 a), Cl (5 b)) um; nach der Röntgenstrukturanalyse ist der 1,1′‐Ferrocendiolato‐Rest in 5 a, b an zwei verschiedene Phosphoratome gebunden. Dagegen werden die 1,1′‐Ferrocendithiolat‐ und 1,1′‐Ferrocendiselenolat‐Reste in fcS2[P3N3X4] (X  F (6 a), Cl (6 b)) bzw. fcSe2[P3N3X4] (X  F (7a), Cl (7 b)) jeweils nur an ein Phosphoratom angekoppelt, so daß spirocyclische 1,2‐Dichalkogena‐2‐phospha[3]ferrocenophane entstehen. Alle neuen Produkte wurden anhand ihrer 1H‐, 13C‐ und 31P‐NMR‐Spektren und der EI‐Massenspektren charakterisiert; für 5 a, b und 6 a wurde die Molekülstruktur durch Röntgenstrukturanalyse bestimmt.
Mesityloxomolybdän‐ und ‐wolfram‐Verbindungen. I. Die Struktur von LiMoO2Me2Mes(OEt2)2
Authors: Kirsten G. , Görls H. , Seidel W.
Published: December 2004

Die Struktur der bekannten, aus MoO2Mes2 1 und LiMe dargestellten Verbindung LiMoO2Me2Mes(OEt2)2 2 [2] sowie ihre NMR‐spektroskopischen Daten werden mitgeteilt. 2 bildet ein in der Raumgruppe P1 kristallisierendes Dimer durch Verknüpfung zweier [MoO2Me2Mes]−‐Anionen über Oxo‐Liganden durch zwei Kationen [Li(OEt2)2]+. Der gebildete [‥OMoOLi‥]2− Achtring ist eben.
Zur Polymorphie von SrNi2P2 sowie zur Kristallstruktur von BaNi2P2
Authors: Keimes V. , Johrendt D. , Mewis A. , Huhnt C. , Schlabitz W.
Published: December 2004

SrNi2P2 und BaNi2P2 wurden durch Erhitzen entsprechender Elementgemenge dargestellt und röntgenographisch mit Einkristallmethoden untersucht. Die Sr‐Verbindung kristallisiert bei Normaltemperatur in einer Überstruktur des ThCr2Si2‐Typs (NT‐SrNi2P2: Immm; Z = 6; a = 3,951(2), b = 11,853(2), c = 10,432(2) Å), die durch Auslenkung der Atome aus den idealen Positionen verursacht wird. Die PP‐Abstände längs [001] betragen 2,45 und 3,28 Å. Die Verbindung durchläuft mit steigender Temperatur bei 45°C (Normaldruck) sowie mit zunehmendem Druck bei ca. 4 kbar (Normaltemperatur) jeweils eine Phasenumwandlung 1. Ordnung und kristallisiert dann im unverzerrten ThCr2Si2‐Strukturtyp (I4/mmm; Z = 2). Während bei der Hochtemperaturphase (HT‐SrNi2P2: a = 3,948(1), c = 10,677(3) Å; 100°C) der PP‐Abstand längs [001] 3,12 Å beträgt, liegt er bei der Hochdruckphase (HD‐SrNi2P2: a = 4,003(1), c = 9,761(2) Å; ca. 4 kbar) dem c/a‐Verhältnis zufolge vermutlich bei 2,45 Å. Die Gründe für die Phasenumwandlungen werden an Hand der elektronischen Struktur diskutiert, BaNi2P2 (a = 3,947(1), c = 11,820(1) Å) kristallisiert ebenfalls im ThCr2Si2‐Typ, der PP‐Abstand längs [001] ist hier auf 3,71 Å aufgeweitet.
Bildung des „superoktaedrischen”︁ Heteropolyanions [Ni(TaF6)6]4− bei der Oxidation von Tantal mit Ammoniumfluorid an der Monel‐Wand
Authors: Schöning Robert‐A. , Meyer Gerd
Published: December 2004

Einige Einkristalle von (NH4)4[Ni(TaF6)6] wurden neben (NH4)[TaF6] bei der Umsetzung von (NH4)F mit Tantal‐Pulver in einer im Helium‐Lichtbogen verschweißten Monel‐Ampulle bei 400°C erhalten. Die Kristallstruktur (trigonal, R‐3c (Nr. 167), Z = 6, a = 1723,0(2); c = 2166,6(21) pm; R1 = 0,0303, WR2 = 0,0609) enthält das „superoktaedrische”︁ Heteropolyanion [Ni(TaF6)6]4− neben (NH4)+‐Ionen; sie kann als ein Derivat des K4CdCl6‐Typs gemäß (NH4)4[Ni(TaF6)6]K4[Cd(Cl)6] aufgefaßt werden.
Die Kristallstruktur von (Al0,5Ga0,5)CuOAsO4 – Kupfer zwischen planarer und geschlossener Koordination
Authors: Moser P. , Jung W. , Schuster H.‐U.
Published: December 2004

Einkristalle des neuen Oxidarsenats (Al0,5Ga0,5)CuOAsO4 (monoklin, P21/c, a = 734,3(2) pm, b = 1024,79(9) pm, c = 563,4(2) pm, β = 99,93(1)°, Z = 4) wurden durch Oxidation von Al/As/Cu/Ga‐Legierungen im Sauerstoffstrom erhalten. Die Kristallstruktur wurde aus Vierkreisdiffraktometer‐Daten bestimmt (w2R = 0,039 für 1211 F2‐Werte und 76 Parameter). [Cu2O6]‐Doppelquadrate sind in Schichten senkrecht zur a‐Achse so angeordnet, daß für Kupfer eine [4 + 1]‐Koordination durch Sauerstoffatome resultiert, die als Übergang von quadratisch‐planarer zu quadratisch‐pyramidaler Koordination interpretiert werden kann. In [100]‐Richtung wechseln Schichten aus eckenverknüpften (Al/Ga)O4− und AsO4−Tetraedern mit gewellten Cu‐Schichten ab.
Disupersilylmetalle (tBu3Si)2M und Supersilylmetallhalogenide tBu3SiMX mit M  Zn, Cd, Hg: Synthesen, Strukturen, Eigenschaften
Authors: Wiberg N. , Amelunxen K. , Lerner H.‐W. , Nöth H. , Appel A. , Knizek J. , Polborn K.
Published: December 2004

Disupersilylmetalle (tBu3Si)2Zn (farblos), (tBu3Si)2Cd (blaßgelb), (tBu3Si)2Hg (blaßgelb) und Supersilylmetallhalogenide tBu3SiZnCl(THF) (farblos), tBu3SiCdI (farblos), tBu3SiHgCl (farblos) bilden sich in THF durch Einwirkung von tBu3SiNa auf ZnCl2, CdI2, HgCl2 im Molverhältnis 2 : 1 bzw. 1 : 1. THF läßt sich durch TMEDA unter Bildung von tBu3SiZnCl(TMEDA) (farblos) ersetzen, (tBu3Si)2Zn durch Einwirkung von BiCl3 oder BBr3 in tBu3SiZnCl (farblos) oder tBu3SiZnBr (farblos) umwandeln. Gemäß Röntgenstrukturanalysen sind die Verbindungen (tBu3Si)2M monomer mit linearen SiMSi‐Gerüsten, wogegen tBu3SiZnBr und tBu3SiHgCl tetramer sind, und zwar in ersterem Falle mit regulärem, in letzterem mit ausgeprägt irregulärem kubischem M4X4‐Gerüst. Die Verbindungen sind bis 200°C thermostabil (Ausnahme (tBu3Si)2Cd), photolabil und vergleichsweise stabil gegen Wasser und Sauerstoff. Die Disupersilylmetalle wirken als Quellen für Supersilylradikale tBu3Si (bei Bestrahlung) sowie als milde Supersilanidierungsmittel (z. B. (tBu3Si)2Zn/BBr3 → tBu3SiZnBr/tBu3SiBBr2), die Supersilylmetallhalogenide als Lewis‐Säuren (Bildung von tBu3SiMX · Donor) und Elektrophile (z. B. tBu3SiHgCl/RLi → tBu3SiHgR/LiCl).
Hochmolekulare Perchlorsiloxane
Authors: Binnewies M. , Jerzembeck M. , Wilkening A.
Published: December 2004

Die Reaktion von SiCl4 mit O2 in der Gasphase verläuft nicht spontan zu den thermodynamisch begünstigten Endprodukten SiO2 und Cl2. Bei Reaktionstemperaturen um 1300 K lassen sich zahlreiche Zwischenstufen SinOmCl4n−2m (Perchlorsiloxane) nachweisen und isolieren. Massenspektrometrische Untersuchungen zeigen die Bildung von Chlorsiloxanen mit n = 2…65 und m/n = 0,5…1,7; es wurden Molmassen bis 7000 D nachgewiesen. Auch die sehr hochmolekularen Chlorsiloxane haben typisch molekulare Eigenschaften: Sie sind löslich in unpolaren Solventien wie Hexan und unzersetzt verdampfbar. Es ergaben sich keine Hinweise darauf, daß die SiO‐Gerüste in den gebildeten Siloxanen Ausschnitte aus einer der Strukturen der SiO2‐Modifikationen darstellen.
Darstellung, Kristallstrukturen, Schwingungsspektren und Normalkoordinatenanalyse von [(Mo6Br)Y]2−; Ya  CN, NCS
Authors: Simsek M. K. , Bublitz D. , Preetz W.
Published: December 2004

Bei der Umsetzung von [(Mo6Br)Bra6]2− mit AgNO3 Aceton und anschließender Zugabe von KCN bzw. KNCS entstehen das Hexacyano‐ bzw, das Hexaisothiocyanatoderivat [(Mo6Br)Y]2−, Ya  CN, NCS. Röntgenstrukturanalysen sind an Einkristallen von (Ph4P)2[(Mo6Br)(CN)a 6 · 4H2O (1) (triklin, Raumgruppe P1, a = 11,63(3), b = 11,85(1), c = 14,23(5) Å, ş= 71,8(1)°, β = 67,6(3)°, γ = 62,8(1)°, Z = 1) und (n‐Bu4N)2][(Mo6Br)(NCS) a6] · 2Et2O (2) (monoklin, Raumgruppe P21/n, a =11,483(3), b = 16,348(5), c = 20,059(6) Å, β = 95,44(3)°, Z = 2) durchgeführt worden. In (1) liegen die über C gebundenen Cyanoliganden als faciale Gruppen mit MoCN‐Winkeln von 168,0–171,5° und 174,1–175,7° vor. In (2) bilden die über N koordinierten Isothiocyanatogruppen in den beiden apikalen Positionen MoNC‐Winkeln von 164,4°, die äquatorialen Winkel von 172,7–173,5°. Unter Verwendung der röntgenographisch ermittelten Molekülparameter werden die bei 10 K registrierten IR‐ und Raman‐Spektren der (n Bu4N)‐Clustersalze durch Normalkoordinatenanalysen auf der Basis eines modifizierten Valenzkraftfeldes zugeordnet. Die Valenzkraftkonstanten betragen für fd(MoMo) = 1,41 (CNa) bzw. 1,43 (NCSa), fd(MoBri) = 0,97 (CNa) bzw. 0,96 (NCSa), fd(MoC) = 1,62 und fd(MoN) = 2,09 mdyn/Å.
Komplexchemie P‐reicher Phosphane und Silylphosphane. XIV. Phosphinophosphiniden tBu2PP als Ligand in den Pt‐Komplexen [η2‐{tBu2PP}Pt(PPh3)2] und [η2‐{tBu2PP}Pt(PEtPh2)2]
Authors: Krautscheid H. , Matern E. , Kovacs I. , Fritz G. , Pikies J.
Published: December 2004

[η2‐{tBu2PP}Pt(PPh3)2] 1 und [η2‐{t Bu2PP}Pt(PEtPh2)2] 2 sind die ersten Komplexverbindungen des tBu2PP 5. Sie entstehen bei der Umsetzung von tBu2PP  P(Me)tBu2 3 mit [η2‐{H2CCH2}Pt(PPh3)2] 6 bzw. [η2‐{H2C  CH2}Pt(PEtPh2)2] 7 unter Abspaltung von tBu2PMe. Verbindung 2 ist beständiger als 1. Mit tBu2PMe bildet 1 das [η2‐{tBu2PP} Pt(PPh3)(PtBu2Mc)] 10. Bei der Umsetzung von 6 mit 3 entsteht ebenfalls 10, weil das bei der Bildung von 1 freiwerdende tBu2PMe mit 1 weiterreagiert. Die Strukturen von 1 und 2 sind über ihre 1H‐ und 31P‐NMR‐Spektren, die von 2 zusätzlich durch eine Röntgenstrukturanalyse gesichert. 2 kristallisiert monoklin in P21/n mit a = 1222,36(7) pm, b = 1770,1(1) pm, c = 1729,7(1) pm, β = 108,653(6)°.
Untersuchungen zum System Bi2O3/BiI3
Authors: Schmidt M. , Oppermann H. , Brückner H. , Binnewies M.
Published: December 2004

Die Temperaturabhängigkeit der Zersetzungsdrücke der auf dem quasibinären Schnitt Bi2O3/BiI3 existierenden ternären Verbindungen wurde durch Gesamtdruckmessungen mit dem Membrannullmanometer und dem Massenspektrometer ermittelt. Das Zustandsbarogramm für das System wurde aufgestellt und das Zustandsdiagramm präzisiert. Unter Zugrundelegung der Zersetzungsgleichungen wurden die Standardbildungsenthalpien und Standardentropien der festen ternären Phasen hergeleitet:

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Ternäre Hydroxide. I. Synthese, Struktur und Eigenschaften von Li2[Sn(OH)6] · 2 H2O
Authors: Reuter H. , Bargon G.
Published: December 2004

Farblose Kristalle von Li2[Sn(OH)6] · 2 H2O wurden durch Umsetzung von SnCl4 mit LiOH in wäßriger Phase erhalten. Die Kristallstruktur der Verbindung konnte an Einkristallen aufgeklärt werden.

Li2[Sn(OH)6] · 2 H2O: monoklin, P21/n (Nr. 14), a = 502.3(1), b = 692.3(1), c = 1020.2(3) pm, β = 99.78(1)°, V = 349.6(2) · 106 pm3, Z = 2, R/Rw = 0.0192/0.0472, N(I) > 2σ(I) = 1527, N(Par.) = 54.

Innerhalb des Kristallverbandes sind nur wenig verzerrte, oktaedrische [Sn(OH)6]2−‐Ionen über Wasserstoffbrückenbindungen mit Wassermolekülen zu Schichten verknüpft, die ihrerseits untereinander über tetraedrisch koordinierte Lithium‐Ionen verbunden sind; die Struktur ist in Übereinstimmung mit den IR‐Daten und Ergebnissen der 119Sn‐Festkörper‐NMR‐Spektroskopie; Hydratwasser wird bei 117.1°C abgespalten, die Kondensationsreaktion zum ternären Oxid erfolgt bei 257.7°C.
Mimotope‐hormesis and mortalin/grp75/mthsp70: a new hypothesis on how infectious disease‐associated epitope mimicry may explain low cancer burden in developing nations
Authors: Deocaris Custer C. , Taira Kazunari , Kaul Sunil C. , Wadhwa Renu
Published: December 2004

It is generally observed that countries with heavy infectious burden show lower cancer incidence as compared to more affluent nations. With the emerging paradigm on microbial heat shock proteins (hsps) as molecular link between infections and autoimmune diseases, we posit a new hypothesis, the “mimotope‐hormesis”, on the immunologic impact of infections on regional cancer prevention. According to this, assaults of infection during early adulthood could fortify the immune system to evoke more potent defenses against late‐onset diseases, such as cancer, via autoimmunity. Interestingly, both experimental and clinical data support the beneficial role of autoimmunity in long‐term cancer survivors. We illustrate this by a comprehensive in silico mimotope (epitope mimicry) analysis of human infectious pathogens against mortalin (mthsp70/PB74/GRP75), a type of hsp70 protein involved in control of cell proliferation, immortalization and tumorigenesis.
Pre‐symptomatic detection of prions by cyclic amplification of protein misfolding
Authors: Soto Claudio , Anderes Laurence , Suardi Silvia , Cardone Franco , Castilla Joaquin , Frossard Marie-Jose , Peano Sergio , Saa Paula , Limido Lucia , Carbonatto Michaela , Ironside James , Torres Juan-Maria , Pocchiari Maurizio , Tagliavini Fabrizio
Published: December 2004

Transmissible spongiform encephalopathies (TSEs) are neurodegenerative disorders affecting humans and animals. At present, it is not possible to recognize individuals incubating the disease before the clinical symptoms appear. We investigated the effectiveness of the “Protein Misfolding Cyclic Amplification” (PMCA) technology to detect the protease‐resistance disease‐associated prion protein (PrPres) in pre‐symptomatic stages. PMCA allowed detection of PrPres in the brain of pre‐symptomatic hamsters, enabling a clear identification of infected animals as early as two weeks after inoculation. Furthermore, PMCA was able to amplify minute quantities of PrPres from a variety of experimental and natural TSEs. Finally, PMCA allowed the demonstration of PrPres in an experimentally infected cow 32 month post‐inoculation, that did not show clinical signs and was negative by standard Western blot analysis. Our findings indicate that PMCA may be useful for the development of an ultra‐sensitive diagnostic test to minimize the risk of further propagation of TSEs.
Bedrock response to Llanquihue Holocene and present‐day glaciation in southernmost South America
Authors: Ivins Erik R. , James Thomas S.
Published: December 2004

Modern geodetic techniques, such as precise Global Positioning System (GPS) measurements and high resolution space gravity mapping, make it possible to measure the present‐day rate of viscoelastic gravitational Earth response to present and past glacier mass change. Patagonia is a rapidly evolving glacial environment. Over the past decade, the local rate of surface stress unloading may be the largest anywhere on the planet. We compute the present‐day land uplift rate that could be observed using bedrock GPS measurements. The Little Ice Age (LIA) of the past half millennium generates large vertical rates since the underlying mantle material is likely to have anomalously low viscosity owing to late‐Neogene ridge subduction.
Convective instability in ice I with non‐Newtonian rheology: Application to the icy Galilean satellites
Authors: Barr Amy C. , Pappalardo Robert T. , Zhong Shijie
Published: December 2004

At the temperatures and stresses associated with the onset of convection in an ice I shell of the Galilean satellites, ice behaves as a non‐Newtonian fluid with a viscosity that depends on both temperature and strain rate. The convective stability of a non‐Newtonian ice shell can be judged by comparing the Rayleigh number of the shell to a critical value. Previous studies suggest that the critical Rayleigh number for a non‐Newtonian fluid depends on the initial conditions in the fluid layer, in addition to the thermal, rheological, and physical properties of the fluid. We seek to extend the existing definition of the critical Rayleigh number for a non‐Newtonian, basally heated fluid by quantifying the conditions required to initiate convection in an ice I layer initially in conductive equilibrium. We find that the critical Rayleigh number for the onset of convection in ice I varies as a power (−0.6 to −0.5) of the amplitude of the initial temperature perturbation issued to the layer, when the amplitude of perturbation is less than the rheological temperature scale. For larger‐amplitude perturbations, the critical Rayleigh number achieves a constant value. We characterize the critical Rayleigh number as a function of surface temperature of the satellite, melting temperature of ice, and rheological parameters so that our results may be extrapolated for use with other rheologies and for a generic large icy satellite. The values of critical Rayleigh number imply that triggering convection from a conductive equilibrium in a pure ice shell less than 100 km thick in Europa, Ganymede, or Callisto requires a large, localized temperature perturbation of a few kelvins to tens of kelvins to soften the ice and therefore may require tidal dissipation in the ice shell.
Development of common variable immunodeficiency in a patient with Evans syndrome treated by autologous stem cell transplantation
Authors: Starý Jan , Sedláček Petr , Vodvářková Šárka , Gašová Zdenka , Bartůňková Jiřina
Published: December 2004

We describe a case report of a patient who developed common variable immunodeficiency (CVID) after autologous haematopoietic stem cell transplantation (SCT) for recurrent Evans syndrome. The disease manifested as attacks of haemolytic anaemia, thrombocytopenia and neutropenia from the age of 12 years. Presence of autoantibodies to blood elements was confirmed together with C4 deficiency. The patient also suffered from dermatitis herpetiformis Duhring without signs of coeliac disease. Autologous T cell‐depleted peripheral blood stem cell (PBSC) transplant following conditioning regimen was performed at the age of 20 years. Immunological reconstitution was incomplete and 2 years after SCT he fulfilled laboratory criteria for common variable immunodeficiency (CVID). The patient was found to be a carrier of a risk haplotype for development of CVID DRB1*03/DQB1*0201. We conclude that T cell‐depleted SCT here performed for autoimmune manifestations can hasten development of CVID in genetically predisposed patients.
Unusual and severe disease course in a child with ataxia‐telangiectasia
Authors: Meyts Isabelle , Weemaes Corry , De Wolf‐Peeters Chris , Proesmans Marijke , Renard Marleen , Uyttebroeck An , De Boeck Kris
Published: December 2004

Ataxia‐telangiectasia (AT) is an autosomal recessive syndrome of combined immunodeficiency. Hallmarks of the disease comprise progressive cerebellar ataxia, oculocutaneous telangiectasia, cancer susceptibility and variable humoral and cellular immunodeficiency. We describe a patient with AT presenting with autoimmune haemolytic anaemia, neutropenia, hepatosplenomegaly, lymphadenopathy and hyper‐IgM at the age of 6 months. At the age of 26 months she developed persistent fever, progressive lymphadenopathy and pulmonary nodular infiltrates, which were responsive to steroid therapy.
Plasma cytokine profiles in patients with celiac disease and selective IgA deficiency
Authors: Cataldo Francesco , Lio Domenico , Marino Vincenzo , Scola Letizia , Crivello Antonio , Corazza G. R. ,   Working Groups of the SIGEP and 'Club del Tenue'
Published: December 2004

Celiac disease (CD) and selective IgA deficiency (IgAD) are frequently associated, and share the same genetic background. The aim of the present study was to evaluate both Type 1 and 2 plasma cytokine levels in CD and in CD‐IgAD. IL‐2, TNF‐α, IL‐10, IL‐4 and IL‐13 plasma levels were measured both at diagnosis and after a gluten‐free diet (GFD) in 32 CD patients, in 27 CD‐IgAD patients and in 30 healthy controls. IFN‐γ levels were significantly higher in CD and CD‐IgAD than in controls, TNF‐α displayed significantly higher levels in CD‐IgAD when compared both with controls and with CD, and IL‐2 was in CD‐IgAD significantly increased respect to controls. Kinetics of the Type 1 cytokine plasma levels did not show a clear relationship with the GFD in both groups of CD patients, and particularly in those with IgAD. IL‐4 and IL‐13, both at diagnosis and after a GFD, were not significantly different in controls and in celiac patients (with and without IgAD). IL‐10, whose production is stimulated by the TNF‐α, had significantly higher plasma levels in CD‐IgAD, but not in CD patients, with a significant decrease after a GFD. CD and especially CD‐IgAD patients display persistently higher pro‐inflammatory cytokine levels, suggesting a persistent state of activation of pro‐phlogistic signals in CD, particularly when IgAD coexists. Serial measurement of serum IL‐10 may be an adjunctive evaluating criterion in the follow‐up of CD‐IgAD patients.
Bronchial hyper‐responsiveness and atopy in urban, peri‐urban and rural South African children
Authors: Steinman Harris A. , Donson Hilton , Kawalski Michelle , Toerien Ann , Potter Paul C.
Published: December 2004

Twenty years ago, the prevalence of atopic sensitization and bronchial hyper‐responsiveness (BHR) in Xhosa children in a rural location in South Africa was very low. The aim of this study was to document the current prevalence of these two indices by comparing traditional rural Xhosa children, recently urbanized Xhosa children and established city white children, and to consider factors that may account for the observed increase in all of these groups. One thousand four hundred and fifty‐seven school children aged 10–14 years from the rural Transkei, from a recently urbanized peri‐urban area and from urban Cape Town areas were studied using a questionnaire. Four hundred and eighteen children had histamine challenges, and 492 tests for atopy were also conducted. As determined by bronchial challenge with histamine, 17% of rural and 34.4% of recently urbanized Xhosa children had increased BHR, a marked increase from the 0.03% and 3.17% prevalence of increased BHR previously found using the exercise challenge. The prevalence of increased BHR in white urban children was 33%. Sensitization to one or more aero‐allergens, as indicated by CAP RAST tests, was present in 36.6% of the rural Xhosa children with normal BHR and in 62.5% of those with increased BHR, a striking increase from that of previous studies. Atopic sensitization to one or more aero‐allergens, as indicated by a skin prick test (SPT), was found in 42.3% of the recently urbanized Xhosa children and 45% of urbanized white children. We have also documented sensitization to house dust mites in the rural Xhosa children for the first time. Passive cigarette smoking was not identified as a risk factor for increased BHR or atopy. Wood smoke in the indoor environment did not play a role in the rural Xhosa children's BHR. Ascaris infection does not appear to play any modifying role in the development of increased BHR in the rural or urban children. We have found that increases in BHR in the rural and recently urbanized Xhosa children develop independently of increases in atopy. Our results challenge the ‘hygiene’ hypothesis as a complete explanation for the recent dramatic worldwide increases in allergic diseases.
Urinary leukotriene E4 levels in children with allergic rhinitis treated with specific immunotherapy and anti‐IgE (Omalizumab)
Authors: Kopp Matthias Volkmar , Mayatepek Ertan , Engels Eva , Brauburger Jens , Riedinger Frank , Ihorst Gabriele , Wahn Ulrich , Kuehr Joachim
Published: December 2004

Recently, we were able to demonstrate that Omalizumab, a humanized monoclonal anti‐IgE antibody, reduces in vitro leukotriene (LT) release of peripheral leukocytes stimulated with allergen in children with allergic rhinitis undergoing allergen immunotherapy. The aim of this study was to investigate the effect of anti‐IgE in combination with specific immunotherapy (SIT) on urinary leukotriene E4 (LTE4) levels. Children and adolescents with sensitization to birch and grass pollens and suffering from seasonal allergic rhinitis were included in a phase III, placebo‐controlled, multicenter clinical study. Within the four‐arm study, patients were randomized to receive SIT for either birch or grass pollen and to receive either subcutaneous anti‐IgE or placebo for 24 weeks during the pollen season. From a total population of 225 children, we collected three urine samples in a subgroup of 19 children [n = 12 boys (63%); mean age 11.8 years; range 7.2–17.5 years; Group A (n = 10): SIT (grass or birch) + anti‐IgE; Group B (n = 9): SIT (grass or birch) + placebo]. Urine samples were collected before, during and at the end of treatment. Endogenous urinary LTE4 was separated by high‐performance liquid chromatography (HPLC) and determined by enzyme immunoassay with a specific antibody. No differences in urinary LTE4 concentrations were observed between the anti‐IgE and the placebo groups before (A: 35.2; B: 36.5 nmol/mol creatinine), during (A: 27.0; B: 29.3) and after treatment (A: 28.9; B: 26.5 nmol/mol creatinine). We conclude that urinary LTE4 levels are not helpful in monitoring patients treated with anti‐IgE and SIT.
Low‐dose theophylline in childhood asthma: a placebo‐controlled, double‐blind study
Authors: Suessmuth Sandra , Freihorst Joachim , Gappa Monika
Published: December 2004

Regular anti‐inflammatory treatment is essential in treating persistent asthma. Most commonly, inhaled corticosteroids (ICS) are used. However, especially in children, there is concern about the long‐term safety of ICS such that doses should be kept to a minimum. The use of theophylline has decreased because of frequent side‐effects in therapeutic doses. In adults, there have been reports about an immunomodulatory effect of low‐dose theophylline. To study the clinical and immunomodulatory effect in children, 36 patients (mean age 12.5 SD 2.4 years) with moderate, persistent asthma on regular ICS were recruited into a placebo‐controlled, double‐blind study. After a 6‐week run‐in period, patients received either theophylline 10 mg/kg bodyweight or placebo for 12 weeks. Diary cards, lung function, peripheral blood lymphocyte subpopulations and serum eosinophil cationic protein (sECP) were assessed. In the treatment group, mean serum theophylline was 7.1 mg/l. There was no change in symptoms or use of rescue medication. Mean (SD) peak expiratory flow (PEF) increased from 86% (24) to 95% (18) predicted. sECP decreased from 43.2 μg/l (32.5) to 26.5 μg/l (16.9) (p = 0.02). Lymphocyte subpopulations did not change. The study failed to show a beneficial clinical or an immunomodulatory effect of theophylline when used in low doses. These results do not support a more important role of theophylline in the long‐term treatment of moderate childhood asthma.
A review of once‐daily delivery of anti‐asthmatic drugs in children
Authors: Dubus Jean‐Christophe , Anhoj Jacob
Published: December 2004

Determining which drug is suitable for, and which patient can benefit from, a once‐daily dose of prophylactic treatment is important for practitioners who want to improve therapeutic compliance in children with asthma. According to the literature, once‐daily delivery of cromolyn sodium, nedocromil or beclomethasone dipropionate must be avoided. On the other hand, switching from a twice‐daily to a once‐daily regimen is efficient and safe only in children with well‐controlled asthma using nebulized or dry‐powder budesonide, dry‐powder fluticasone propionate, flunisolide, or sustained‐release theophylline. Such information is not available for long‐acting β2‐agonists, except for oral bambuterol. Initiating a once‐daily treatment in previously untreated children can only be based on low doses of inhaled budesonide or on an oral drug, montelukast. Further studies in children with severe asthma or treated with metered‐dose inhalers and spacer devices are required before recommending a once‐daily drug delivery in such situations.
Circadian variations in serum eosinophil cationic protein, and serum and urine eosinophil protein X
Authors: Wolthers O. D. , Heuck C.
Published: December 2004

Biochemical evaluation of inflammation may be a useful adjunct to measures of pulmonary function and symptoms in children with asthma. However, little data have been provided to validate the markers in children. The aim of the present study was to assess circadian variations in serum eosinophil cationic protein (ECP), and serum and urine eosinophil protein X (EPX) in children. Five girls and two boys aged 10–14 years were studied. The first sample of urine consisted of urine collected from 24.00 hours the night before until 08.00 hours on the morning of the day of investigation. Thereafter urine was collected at 4‐h intervals until 24.00 hours and in another 8‐h interval from 24.00 to 08.00 hours. Blood samples for assessment of serum ECP and serum EPX were collected every 2 h during the 24 h. Statistically significant circadian variations in serum ECP (F=3.2, p=0.002), serum EPX (F=3.1, p=0.002) and in urine EPX/creatinine (F=5.4, p=0.003) were detected. The concentrations were higher during the night compared to daytime. Peak levels of serum ECP (mean [± SEM]) were found at 06.00 hours (16.3 [5.3] µg/l), trough levels at 08.00 hours (3.9 [0.7] µg/l) (p=0.01). Peak levels of serum EPX were seen at 06.00 (43.7 [9.5] µg/l) with trough levels at 12.00 hours (22.0 [3.5] µg/l) (p=0.01). Peak levels of urine EPX/creatinine occurred in urine collected from 24.00 to 08.00 hours (90.0 [27.7] µg/mmol), trough levels in the 16.00–20.00 hours sample (29.7 [8.9] µg/mmol) (p=0.02). Serum ECP, serum EPX and urine EPX exhibit a circadian variation in children with nocturnal and early morning peak levels. To avoid confounding influence from circadian variations in ECP and EPX in clinical studies blood or urine should be sampled at consistent times.
Treatment of allergic alveolitis with methylprednisolone pulse therapy
Authors: Chen Christiane , Kleinau Irene , Niggemann Bodo , Weinhold Nathalie , Wahn Ulrich , Paul Karl
Published: December 2004

We report on a 13‐year‐old‐boy who had been admitted to our hospital for dyspnea, hypoxia, and pulmonary infiltrates. The diagnosis of allergic alveolitis was based on history (provocation by exposure), lung function tests, bronchoalveolar lavage, and transbronchial lung biopsy. No specific allergen could be identified. Five courses of methylprednisolone pulse therapy (15 mg/kg on three consecutive days) stabilized the patient with normalization of lung function and blood gas analysis. Between pulses the boy returned to his home on a farm without relapse. It is estimated that the effect of a single pulse lasted for at least 2–4 weeks. We conclude that pulse therapy can be used instead of continuous therapy in this rare disease in childhood.
Cytokine, chemokine and secretory IgA levels in human milk in relation to atopic disease and IgA production in infants
Authors: Böttcher Malin F. , Jenmalm Maria C. , Björkstén Bengt
Published: December 2004

The relationship between breast‐feeding, IgA production and development of atopic disease in children is a matter of controversy. Some of this controversy might be due to individual differences in the composition of breast milk. The aim of this study was to relate the levels of cytokines, chemokines and secretory (S)‐IgA antibodies in breast milk to the development of atopic manifestation and salivary IgA production in infants. Cytokine, chemokine and SIgA levels, as measured with enzyme‐linked immunosorbent assay (ELISA), in colostrum and mature milk were analyzed in relation to the development of positive skin‐prick tests (SPT), allergic symptoms and salivary IgA antibody production during the first 2 years of life in 53 infants. There was no association between levels of IL‐4, ‐5, ‐6, ‐8, ‐10, ‐13, ‐16, IFN‐γ, TGF‐β1, ‐β2, RANTES, eotaxin or SIgA levels in the breast milk with either SPT‐positivity, development of allergic symptoms or salivary IgA levels during the first 2 years of life in the infants. Thus, differences in the composition of cytokines, chemokines and SIgA in breast milk did not, to any major degree, affect the development of a positive SPT, atopic symptoms, nor salivary IgA antibody production during the first 2 years of life.
Hematologic abnormalities in children and young adults receiving tacrolimus‐based immunosuppression following cardiothoracic transplantation
Authors: Dobrolet Nancy C. , Webber Steven A. , Blatt Julie , Michaels Marian , Kiaffas Maria , Kurland Geoffrey , Boyle Gerard J.
Published: December 2004

Abstract: To define the incidence, course, and etiology of hematologic abnormalities in children on tacrolimus‐based immunosuppression, we reviewed records of 106 transplant patients (70 heart, 16 heart and lung, 20 double lung), 0–21 yr of age, who were transplanted at the Children's Hospital of Pittsburgh from 1989 to 1997. Fifty‐four of the 106 patients (51%) developed 65 abnormal hematologic episodes (32 anemia, nine neutropenia, nine thrombocytopenia, 15 simultaneous anemia and neutropenia with or without thrombocytopenia). Common etiologies included: infections, post‐transplant lymphoproliferative disease, and medications. Eleven episodes (seven anemia, one neutropenia, and three simultaneous anemia and neutropenia) had unclear etiologies and process of elimination suggested an association with tacrolimus. Interventions included filgrastim (effective in 15 of 15 patients, with resolution of neutropenia in a median of 5 days) and epoetin alfa (effective in five of 16 patients, including four of four patients with anemia possibly related to tacrolimus). Five patients (two with neutropenia and three with simultaneous neutropenia and anemia) were switched to cyclosporin A (CsA); rapid resolution occured in four of the five patients, suggesting a possible association of the hematologic abnormalities with tacrolimus. In summary, hematologic abnormalities are common in children on tacrolimus‐based immunosuppression. Most of these hematologic abnormalities are caused by common etiologies; however, a sub‐population exists where tacrolimus may be the etiologic agent. Anemia and neutropenia respond to treatment with epoetin alfa and filgrastim. After thorough investigation, a trial switch to CsA may be warranted.
Hypophosphatemia and hypouricemia in pediatric allogeneic bone marrow transplant recipients
Authors: Uçkan Duygu , Çetin Mualla , Dida Abdi , Batu Abdulselam , Tuncer Murat , Tezcan İlhan
Published: December 2004

Abstract: Increased phosphate (P) uptake by the replicating neutrophils during engraftment syndrome has been described to play a role in the development of hypophosphatemia (HP) in bone marrow transplantation patients, and suggested as a measure of neutrophil recovery. Here, the relationship of serum P with engraftment was determined in 56 children who underwent allogeneic bone marrow transplantation (BMT). Uric acid (UA) levels were also analyzed to study the contribution of cytolysis on P levels. HP and hypouricemia (HU) developed at least once in 63 and 57% of patients respectively, before and until day +20 after transplantation. The minimal values of P and UA were observed at day +10 and were significantly lower than the baseline values (p < 0.01). The mean neutrophil engraftment was at day +13, following the P and UA nadir by 3 days. In addition there was a significant correlation between P and UA levels (p = 0.01). The levels of of both P and UA returned to pretransplant values at day +20. A significant correlation (p < 0.05) between platelet engraftment and P levels was also demonstrated. HP and HU seen in pediatric patients undergoing BMT reflects a combination of pathophysiologic mechanisms.
Tacrolimus‐based immunosuppression with steroid withdrawal in pediatric kidney transplantation – 4‐year experience at a moderate‐volume center
Authors: Jensen Sena , Jackson Elizabeth Connor , Riley Lena , Reddy Sudhakar , Goebel Jens
Published: December 2004

Abstract: Tacrolimus‐based immunosuppression with steroid withdrawal in pediatric kidney transplantation was pioneered at the University of Pittsburgh but is not broadly practiced at other centers. We present our 4‐year experience with a modified Pittsburgh protocol at our own moderate‐volume center. Seventeen pediatric kidney transplant recipients were treated with a tacrolimus‐based immunosuppressive regimen involving steroid withdrawal over 6–12 post‐transplant months in most cases and followed for up to 49 months. Patient and graft survival as well as graft function were excellent, and beneficial effects on several cardiovascular parameters were noted. Complications included fungal infections, glucose intolerance and post‐transplant lymphoproliferative disease and were generally managed successfully. While awaiting longer‐term follow‐up data, we conclude that tacrolimus‐based immunosuppression with steroid withdrawal in pediatric kidney transplantation is potentially beneficial and feasible even at centers managing a rather small number of recipients.
Risk factors for moderate‐to‐severe acute graft‐vs.‐host disease after allogeneic stem cell transplantation in children
Authors: Svennilson Johan , Remberger Mats , Ringdén Olle
Published: December 2004

Abstract: Severe acute graft‐vs.‐host disease (aGVHD) remains a major cause of transplantation‐related mortality. However, because of a graft‐vs.‐leukaemia effect, a mild (grade I) aGVHD is desirable. As risk factors predisposing for aGVHD are not necessarily the same in children and adults, we have performed a retrospective analysis of risk factors (RFs) for grade II–IV aGVHD in 258 paediatric patients undergoing allogeneic stem cell transplantation at our centre. Thirty‐two potential RFs were assessed with univariate analysis in logistic regression. Eleven factors were selected for further evaluation in stepwise elimination multivariate analysis. Three independent RFs were found: (1) donor other than human lekocyte antigen (HLA)‐identical sibling [odds ratio (OR) 6.1, p < 0.001); (2) single drug [cyclosporine A (CsA) or methotrexate (Mtx)] graft‐vs.‐host disease (GVHD) prophylaxis (OR 7.0, p < 0.001); and (3) ABO disparity of any kind (OR 2.4, p = 0.02). The RFs were additive: moderate‐to‐severe aGVHD was seen in none of the patients without any RFs; in 16% with one RF; in 32% with two RFs and in 67% with all three RFs present. Single drug GVHD prophylaxis (CsA or Mtx), any kind of ABO mismatch, and non‐sibling donors are RFs for grade II–IV acute GVHD in paediatric SCT. We encourage the use of combination GVHD prophylaxis in children. ABO mismatch should be considered when choosing between otherwise equally suitable donors.
Regulation of phosphoenolpyruvate carboxylase in Pinus halepensis needles submitted to ozone and water stress
Authors: Fontaine Véronique , Cabané Mireille , Dizengremel Pierre
Published: December 2004

Effects of ozone and/or drought stresses on phosphoenolpyruvate carboxylase (PEPc, EC 4.1.1.31) regulation in Pinus halepensis Mill. needles were assessed over 3 months in controlled conditions. Whereas moderated water stress applied to Aleppo pine had no effect on PEPc activity compared to the control, which was probably related to the high tolerance of this species to drought, ozone stress induced a dramatic increase of PEPc activity in pine needles. This stimulation of the anaplerotic pathway could provide substrates to repair processes, well known for being enhanced upon ozone exposure. The ozone‐increased PEPc activity was related, to a certain extent, to an increase in protein and mRNA levels. The possible role of the stimulation of the phosphorylation status of the enzyme in the increased PEPc activity under ozone was also investigated. Following the demonstration of the existence of the phosphorylation site at the N terminal part of Aleppo pine PEPc, it was shown that, under ozone treatment, the light/dark PEPc activity ratio and the Ki (malate) for PEPc were increased. This strengthens the hypothesis of an ozone‐related post‐translational process, which could be part of an adaptation of the plants to prolonged stress. When ozone and water stress were applied in combination, the enhancement in PEPc activity was only related to changes in gene expression. This difference in PEPc regulation, compared to the effect of single stress, could be the consequence of the specific action of each stress on the enzyme. This study brings new insights into the regulation of PEPc in a C3 plant, Aleppo pine under these stresses. A different regulatory mechanism of PEPc is occurring according to the stress. The physiological implications of the increase in PEPc activity in response to ozone and/or water stress are discussed.
In situ hybridization analysis of protein kinase CK2 expression during plant development
Authors: Espunya M. Carme , Martínez M. Carmen
Published: December 2004

Protein kinase CK2 (EC 2.7.1.37) is a ubiquitous Ser/Thr kinase composed of two subunits, a subunit (catalytic) and a subunit (regulatory). Although CK2 is one of the components of the network that controls the eukaryotic cell cycle, very little is known about the developmental control of its expression, particularly in plants. Using in situ hybridization we have determined the pattern of expression of its two subunits in relation to plant morphogenesis. Our results show a cell‐specific mRNA accumulation, equivalent for both subunits, which suggests a co‐ordinate regulation during development. The spatial and temporal pattern of expression correlates with the appearance of the meristems, and high levels of transcripts are also present in differentiated tissues with high mitotic activity. These results confirm the transcriptional regulation of CK2 and establish a general correlation with cell proliferation in a developmental context. They also provide suggestive evidence for the requirement of CK2 expression for the initiation and organization of meristem activity.
Identification of an allele of CLA1 associated with variegation in Arabidopsis thaliana
Authors: Crowell Dring N. , Packard Clay E. , Pierson Charles A. , Giner José‐Luis , Downes Brian P. , Chary S. Narasimha
Published: December 2004

We have identified a mutant of Arabidopsis thaliana (lvr111) that exhibits a variegated phenotype, reduced isoprenoid pigmentation, and dwarfism in comparison with wild‐type plants. Segregation analysis indicated that this phenotype was caused by a single, semi‐dominant mutation and PCR‐based marker mapping placed the mutation near position 56 on the RI map of chromosome IV. The lvr111 lesion was identified by genomic PCR and sequence analysis as a missense mutation (D306N) in the CLA1 gene (AT4g15560) and complementation analysis confirmed the allelic relationship between lvr111 and CLA1. CLA1 encodes 1‐deoxy‐d‐xylulose 5‐phosphate synthase, which catalyses the first step of the non‐mevalonate isoprenoid biosynthetic pathway. These observations demonstrate that, unlike the albinism caused by severe alleles of CLA1, weaker alleles are associated with leaf variegation.
Stem respiration of Populus species in the third year of free‐air CO2 enrichment
Authors: Gielen Birgit , Scarascia‐Mugnozza Giuseppe , Ceulemans Reinhart
Published: December 2004

Carbon cycling in ecosystems, and especially in forests, is intensively studied to predict the effects of global climate change, and the role which forests may play in ‘changing climate change’. One of the questions is whether the carbon balance of forests will be affected by increasing atmospheric CO2 concentrations. Regarding this question, effects of elevated [CO2] on woody‐tissue respiration have frequently been neglected. Stem respiration of three Populus species (P. alba L. (Clone 2AS‐11), P. nigra L. (Clone Jean Pourtet), and P. × euramericana (Clone I‐214)) was measured in a managed, high‐density forest plantation exposed to free‐air CO2 enrichment (POPFACE). During the period of measurements, in May of the third year, stem respiration rates were not affected by the FACE treatment. Moreover, FACE did not influence the relationships between respiration rate and both stem temperature and relative growth rate. The results were supported by the reported absence of a FACE‐effect on growth and stem wood density.
POR – import and membrane association of a key element in chloroplast development
Authors: Aronsson Henrik , Sundqvist Christer , Dahlin Clas
Published: December 2004

The development of proplastids or etioplasts to chloroplast is visualized by the accumulation of chlorophyll in leaves of higher plants. The biosynthesis of chlorophyll includes a light‐dependent reduction of protochlorophyllide (Pchlide) to chlorophyllide (Chlide). This light‐dependent step is catalysed by the nucleus‐encoded NADPH:Pchlide oxidoreductase (POR, EC 1.6.99.1). POR is active within plastids and therefore has to be translocated over the plastid envelope membranes. The import of chloroplast proteins seems to follow a general import pathway using translocons at the outer and inner envelope membrane. POR cross‐linking to Toc75, one of the major translocon components at the outer envelope membrane, indicates its use of the general import pathway. However, since variations exist within the so‐called general import pathway one has to consider previous data suggesting a novel totally Pchlide‐dependent import pathway of one POR isoform, PORA. The suggested Pchlide dependency of POR import is discussed since recent observations contradict this idea. In the stroma the POR transit peptide is cleaved off and the mature POR protein is targeted to the plastid inner membranes. The correct and stable association of POR to the membrane requires the cofactor NADPH. Functional activity of POR calls for formation of an NADPH–Pchlide–POR complex, a formation that probably takes place after the membrane association and is dependent on a phosphorylation reaction.
The mystique of irreversibility in cyanobacterial heterocyst formation: parallels to differentiation and senescence in eukaryotic cells
Authors: El‐Shehawy Rehab M. , Kleiner Diethelm
Published: December 2004

The formation of cyanobacterial heterocysts is unique in the prokaryotic world: it is the only irreversible collective process. This terminal differentiation resembles senescence and differentiation in the eukaryotic urkingdom. During their cell cycle eukaryotic cells at the restriction point may reversibly proceed from a vegetative phase (G1) into a quiescent state (G0), and then may irreversibly enter the way towards differentiated or senescent cells. In parallel, at commitment point 1 vegetative cells from filamentous cyanobacteria may reversibly form proheterocysts, and then may proceed irreversibly towards mature heterocysts at commitment point 2. While the signals paving the path for differentiation or senescence in eukaryotes are largely unknown, heterocyst development is clearly triggered by nitrogen starvation. The reasons for the irreversibility in both systems are poorly understood. We discuss these questions, especially in the light of recent advances in the molecular biology of cyanobacteria, with emphasis on self‐stabilizing autocatalytic cycles.
Physiological and morphological evidence of brassinosteroid‐biosynthesis inhibition by the fungicide imazalil
Authors: Werbrouck Stefaan P. O. , Saibo Nelson J. M. , Dhuyvetter Hilde , De Schepper Sandra , Van Der Straeten Dominique , Debergh Pierre C.
Published: December 2004

Dark germinated Arabidopsis thaliana Ler seedlings grown on medium with the commonly used imidazole‐type fungicide imazalil (IMA) resemble de‐etiolated (det) brassinosteroid‐deficient mutants. IMA hampers cell elongation in the hypocotyl, but stimulates radial expansion during dark growth. This phenotype could partially be restored by simultaneous addition of 24‐epibrassinolide (EBR). A complete restoration of the hypocotyl length could only be achieved by combining EBR and gibberellic acid. As Arabidopsis thaliana etr1‐3 de‐etiolates on IMA containing medium in the dark, in the same dose‐dependent manner as the wild type, its effects cannot be attributed to the induction of extra ethylene production. Studies with A. thaliana seedlings expressing CPD::GUS show that IMA up‐regulates the expression of CPD, which encodes a key cytochrome P450 enzyme in the brassinosteroid (BR)‐biosynthesis pathway. This effect is reverted by EBR, indicating that the up‐regulation of CPD by IMA might result from the lack of end product brassinolide. Together these data suggest that, in Arabidopsis, one of the effects of IMA is an inhibition of BR‐biosynthesis. IMA is an available and cheap agrochemical that might be a valuable tool for future brassinosteroid research.