bluuebunny/crossref_metadata_2025 huggingface dataset:
trans
-Acting Inhibition of Genomic RNA Dimerization by Rous Sarcoma Virus Matrix Mutants
Authors: Garbitt Rachel A. , Albert Jessica A. , Kessler Michelle D. , Parent Leslie J.
Published: July 2002

The genomic RNA of retroviruses exists within the virion as a noncovalently linked dimer. Previously, we identified a mutant of the viral matrix (MA) protein of Rous sarcoma virus that disrupts viral RNA dimerization. This mutant, Myr1E, is modified at the N terminus of MA by the addition of 10 amino acids from the Src protein, resulting in the production of particles containing monomeric RNA. Dimerization is reestablished by a single amino acid substitution that abolishes myristylation (Myr1E−). To distinguish between
cis
and
trans
effects involving Myr1E, additional mutations were generated. In Myr1E.cc and Myr1E−.cc, different nucleotides were utilized to encode the same protein as Myr1E and Myr1E−, respectively. The alterations in RNA sequence did not change the properties of the viral mutants. Myr1E.ATG− was constructed so that translation began at the
gag
AUG, resulting in synthesis of the wild-type Gag protein but maintenance of the
src
RNA sequence. This mutant had normal infectivity and dimeric RNA, indicating that the
src
sequence did not prevent dimer formation. All of the
src
-containing RNA sequences formed dimers in vitro. Examination of MA-green fluorescent protein fusion proteins revealed that the wild-type and mutant MA proteins Myr1E.ATG−, Myr1E−, and Myr1E−.cc had distinctly different patterns of subcellular localization compared with Myr1E and Myr1E.cc MA proteins. This finding suggests that proper localization of the MA protein may be required for RNA dimer formation and infectivity. Taken together, these results provide compelling evidence that the genomic RNA dimerization defect is due to a
trans
-acting effect of the mutant MA proteins.
Elevated Levels of Interleukin-8 in Serum Are Associated with Hepatitis C Virus Infection and Resistance to Interferon Therapy
Authors: Polyak Stephen J. , Khabar Khalid S. A. , Rezeiq Mohammed , Gretch David R.
Published: July 2002

Hepatitis C virus (HCV), a major cause of liver disease worldwide, is frequently resistant to the antiviral alpha interferon (IFN). We have recently found that the HCV NS5A protein induces expression of the proinflammatory chemokine IL-8 to partially inhibit the antiviral actions of IFN in vitro. To extend these observations, in the present study we examined the relationship between levels of IL-8 in serum, HCV infection, and biochemical response to IFN therapy. Levels of IL-8 were significantly elevated in 132 HCV-infected patients compared to levels in 32 normal healthy subjects and were also significantly higher in patients who did not respond to IFN therapy than in patients who did respond to therapy. This study suggests that HCV-induced changes in levels of chemokine and cytokine expression may be involved in HCV antiviral resistance, persistence, and pathogenesis.
Selective Regulation of Human Immunodeficiency Virus-Infected CD4+Lymphocytes by a Synthetic Immunomodulator Leads to Potent Virus Suppression In Vitro and in hu-PBL-SCID Mice
Authors: Bahr George M. , Darcissac Edith C. A. , Castéran Nathalie , Amiel Corinne , Cocude Cécile , Truong Marie-José , Dewulf Joëlle , Capron André , Mouton Yves
Published: July 2002

We have previously observed that the synthetic immunomodulator Murabutide inhibits human immunodeficiency virus type 1 (HIV-1) replication at multiple levels in macrophages and dendritic cells. The present study was designed to profile the activity of Murabutide on CD8-depleted phytohemagglutinin-activated lymphocytes from HIV-1-infected subjects and on the outcome of HIV-1 infection in severe combined immunodeficiency mice reconstituted with human peripheral blood leukocytes (hu-PBL-SCID mice). Maintaining cultures of CD8-depleted blasts from 36 patients in the presence of Murabutide produced dramatically reduced levels of viral p24 protein in the supernatants. This activity correlated with reduced viral transcripts and proviral DNA, was evident in cultures harboring R5, X4-R5, or X4 HIV-1 isolates, was not linked to inhibition of cellular DNA synthesis, and did not correlate with β-chemokine release. Moreover, c-mycmRNA expression was down-regulated in Murabutide-treated cells, suggesting potential interference of the immunomodulator with the nuclear transport of viral preintegration complexes. On the other hand, daily treatment of HIV-1-infected hu-PBL-SCID mice with Murabutide significantly reduced the viral loads in plasma and the proviral DNA content in human peritoneal cells. These results are the first to demonstrate that a clinically acceptable synthetic immunomodulator with an ability to enhance the host's nonspecific immune defense mechanisms against infections can directly regulate cellular factors in infected lymphocytes, leading to controlled HIV-1 replication.
Genome of Lumpy Skin Disease Virus
Authors: Tulman E. R. , Afonso C. L. , Lu Z. , Zsak L. , Kutish G. F. , Rock D. L.
Published: July 2002

Lumpy skin disease virus (LSDV), a member of the capripoxvirus genus of the
Poxviridae
, is the etiologic agent of an important disease of cattle in Africa. Here we report the genomic sequence of LSDV. The 151-kbp LSDV genome consists of a central coding region bounded by identical 2.4 kbp-inverted terminal repeats and contains 156 putative genes. Comparison of LSDV with chordopoxviruses of other genera reveals 146 conserved genes which encode proteins involved in transcription and mRNA biogenesis, nucleotide metabolism, DNA replication, protein processing, virion structure and assembly, and viral virulence and host range. In the central genomic region, LSDV genes share a high degree of colinearity and amino acid identity (average of 65%) with genes of other known mammalian poxviruses, particularly suipoxvirus, yatapoxvirus, and leporipoxviruses. In the terminal regions, colinearity is disrupted and poxvirus homologues are either absent or share a lower percentage of amino acid identity (average of 43%). Most of these differences involve genes and gene families with likely functions involving viral virulence and host range. Although LSDV resembles leporipoxviruses in gene content and organization, it also contains homologues of interleukin-10 (IL-10), IL-1 binding proteins, G protein-coupled CC chemokine receptor, and epidermal growth factor-like protein which are found in other poxvirus genera. These data show that although LSDV is closely related to other members of the
Chordopoxvirinae
, it contains a unique complement of genes responsible for viral host range and virulence.
CD8+Lymphocytes from Simian Immunodeficiency Virus-Infected Rhesus Macaques Recognize 14 Different Epitopes Bound by the Major Histocompatibility Complex Class I Molecule Mamu-A*01: Implications for Vaccine Design and Testing
Authors: Allen Todd M. , Mothé Bianca R. , Sidney John , Jing Peicheng , Dzuris John L. , Liebl Max E. , Vogel Thorsten U. , O'Connor David H. , Wang Xiaochi , Wussow Michael C. , Thomson James A. , Altman John D. , Watkins David I. , Sette Alessandro
Published: July 2002

It is becoming increasingly clear that any human immunodeficiency virus (HIV) vaccine should induce a strong CD8+response. Additional desirable elements are multispecificity and a focus on conserved epitopes. The use of multiple conserved epitopes arranged in an artificial gene (or EpiGene) is a potential means to achieve these goals. To test this concept in a relevant disease model we sought to identify multiple simian immunodeficiency virus (SIV)-derived CD8+epitopes bound by a single nonhuman primate major histocompatibility complex (MHC) class I molecule. We had previously identified the peptide binding motif of Mamu-A*012, a common rhesus macaque MHC class I molecule that presents the immunodominant SIVgag-derived cytotoxic T lymphocyte (CTL) epitope Gag_CM9 (CTPYDINQM). Herein, we scanned SIV proteins for the presence of Mamu-A*01 motifs. The binding capacity of 221 motif-positive peptides was determined using purified Mamu-A*01 molecules. Thirty-seven peptides bound with apparentKdvalues of 500 nM or lower, with 21 peptides binding better than the Gag_CM9 peptide. Peripheral blood mononuclear cells from SIV-infected Mamu-A*01+macaques recognized 14 of these peptides in ELISPOT, CTL, or tetramer analyses. This study reveals an unprecedented complexity and diversity of anti-SIV CTL responses. Furthermore, it represents an important step toward the design of a multiepitope vaccine for SIV and HIV.
Cyclin T1 Expression Is Mediated by a Complex and Constitutively Active Promoter and Does Not Limit Human Immunodeficiency Virus Type 1 Tat Function in Unstimulated Primary Lymphocytes
Authors: Martin-Serrano Juan , Li Kelvin , Bieniasz Paul D.
Published: July 2002

Cyclin T1 (CycT1), a component of positive-transcription-elongation factor-b (P-TEFb), is an essential cofactor for transcriptional activation by lentivirus Tat proteins. It is thought that low CycT1 expression levels restrict human immunodeficiency virus type 1 (HIV-1) expression levels and replication in resting CD4+lymphocytes. In this study, we undertook a functional analysis of thecycT1promoter to determine which, if any, promoter elements might be responsible for cellular activation state-dependent CycT1 expression. ThecycT1gene contains a complex promoter that exhibits an extreme degree of functional redundancy: five nonoverlapping fragments were found to exhibit significant promoter activity in immortalized cell lines, and these elements could interact in a synergistic or redundant manner to mediatecycT1transcription. Reporter gene expression, mediated by thecycT1promoter, was detectable in unstimulated transfected primary lymphocytes and multiple sites within the promoter could serve to initiate transcription. While utilization of these start sites was significantly altered by the application of exogenous stimuli to primary lymphocytes and two distinct promoter elements exhibited enhanced activity in the presence of phorbol ester, overallcycT1transcription was only modestly enhanced in response to cell activation. These observations prompted a reexamination of CycT1 protein expression in primary lymphocytes. In fact, steady-state CycT1 expression is only slightly lower in unstimulated lymphocytes compared to phorbol ester-treated cells or a panel of immortalized cell lines. Importantly, CycT1 is expressed at sufficient levels in unstimulated primary cells to support robust Tat activity. These results strongly suggest that CycT1 expression levels in unstimulated primary lymphocytes do not profoundly limit HIV-1 gene expression or provide an adequate mechanistic explanation for proviral latency in vivo.
Induction of CD8 T-Cell-Specific Systemic and Mucosal Immunity against Herpes Simplex Virus with CpG-Peptide Complexes
Authors: Gierynska Malgorzata , Kumaraguru Uday , Eo Seong-Kug , Lee Sujin , Krieg Arthur , Rouse Barry T.
Published: July 2002

Oligodeoxynucleotides (ODN) containing unmethylated CpG motifs exert powerful adjuvant activity in vivo and in vitro. Administered with antigen they induce a population of antigen-specific CD8+T cells. In this study we immunized C57BL/6 mice with bioactive CpG ODN combined with an immunodominant epitope derived from herpes simplex virus (HSV) glycoprotein B (amino acids 498 to 505; SSIEFARL) and analyzed the magnitude and durability of the peptide-specific response. The effectiveness of the CD8+T-cell response as measured by peptide-specific tetramers, peptide-induced intracellular gamma interferon expression, and resistance to systemic and mucosal challenge during the acute and memory phases was compared with the response induced by immunization with recombinant vaccinia virus encoding SSIEFARL as a minigene (VvgB498-505). Confirming the reports of others, our results demonstrate that the CpG ODN-peptide approach generates an antigen-specific CD8+T-cell population, but the frequency of CD8+T cells is lower than that induced by VvgB498-505. Nevertheless, the protection level was comparable when mice were systemically and mucosally challenged during the acute phase. However, such responses by both groups waned with time and were functionally less effective. Still, our results indicate that the CpG ODN-peptide immunization system holds promise as a means of selectively inducing a CD8+T-cell response against HSV.
Crystal Structure of Bis(ethylenediphosphinetetraacetic acid)palladium(II) Bis(dihydrogenethylenediphosphinetetraacetato)palladate(II) Tetrahydrate Hydrobromide (1/1): An Unusual Case of Bromide Uncoordinated to Palladium(II)
Authors: Podlaha Jaroslav , Podlahová Jana
Published: July 2002

Synthesis, crystal and molecular structure of the title compound as a representative of the complexes of phosphineacetic acids with soft metal ions is described. Crystal data: triclinic, P1, a = 10.809(1), b = 14.922(1), c = 10.617(1) Å, α = 108.871(7), β = 102.773(9), γ = 102.970(7)°, Z = 1, R = 0.031 for 4 545 observed reflections. The structure is built of layers composed of hydrogen-bonded ligands; the layers are joined, in alternate manner, by Pd(II) ions, water molecules and bromide anions. As an average, one proton of the tetraprotonated ligand is released during complexation even in protic solvent (aqueous acetic acid), resulting in the given ionic composition with non-equivalent Pd(II) centers. The carboxyl groups and, surprisingly, even the bromide ion are not coordinated to Pd. The proton assigned formally to hydrobromic acid was not located and is possibly disordered.
Adsorption of Antimony(III) Ions at Mercury in Acid Chloride Solutions
Authors: Krumbein Angelika , Novotný Ladislav , Retter Utz
Published: July 2002

Interfacial tensions at concentrations of Sb(III) ranging from 2 .10-6 to 5 .10-4 mol l-1 in 0.1 M HCl and 2.9 M HClO4 mixture on the Hg-electrode were measured using the drop-time technique with long drop-times and a controlled convection of the solution. The dependence of the surface excess on concentration was determined. The adsorption was found to obey Langmuir isotherm. From the calculated surface area of antimony of 20 nm2 it was concluded, that complexes of antimony with chloride are the adsorbing species.
Kinetic Study of Oxygen Transfer Reactions from Oxo-Monoperoxo Complexes of Vanadium(V) to Thiolatocobalt(III) Complex in Water and Concentrated Solutions of Electrolytes
Authors: Vollárová Oľga , Benko Ján , Sivák Michal
Published: July 2002

[Co(en)2SCH2CH2NH2]2+ ion is oxidized to [Co(en)2SOCH2CH2NH2]2+ by the oxo-monoperoxovanadium(V) complexes in aqueous media. These reactions are accompanied by oxygen atom transfer from the peroxo ligand to the coordinated sulfur atom. The relative reactivities for each substrate stand in the order: [VO(O2)(ada)]- << [VO(O2)nta]2- ~ H2O2 ~ [VO(O2)(H2O)4]+ < [VO(O2)(quin)2]3- << [VO(O2)(H2O)2(pic)], where ada = N-(carbamoylmethyl)iminodiacetato(2-), nta = nitrilotriacetato(3-), quin = 2,3-pyridinedicarboxylato(2-) and pic = 2-pyridinecarboxylato(1-) ligands. The effect of pH on the second order rate constant for oxidation by monoperoxo-nta complex is in the pH range 4.8-6.5 consistent with equation k(298.2 K) = 0.709 + 1.28 . 105 [H+]. Two new oxo-monoperoxo complexes of vanadium(V), NH4[VO(O2)(ada)] . H2O and (NH4)3[VO(O2)(quin)2] . 3 H2O, were synthesized and characterized. The salt effects on the thiolatocobalt(III) oxidation by vanadium(V) oxo-monoperoxo complexes as well as by H2O2 were studied at 298.2 K in different, up to 5 M solutions of electrolytes. The results can be rationalized in terms of the salt-water interactions.
Synthesis and Antiviral Activity of Acyclic Nucleotide Analogues Derived from 6-(Aminomethyl)purines and Purine-6-carboxamidines
Authors: Hocek Michal , Masojídková Milena , Holý Antonín , Andrei Graciela , Snoeck Robert , Balzarini Jan , De Clercq Erik
Published: July 2002

The synthesis of a series of 9-(2-phosphonomethoxyalkyl) derivatives of 6-(aminomethyl)purine 11, 2-amino-6-(aminomethyl)purine 12 and purine-6-carboxamidine 14 is reported. The 6-cyanopurines 1 and 2 were selectively alkylated with 2-[bis(isopropyloxy)phosphonylmethoxy]alkyl synthons 3 and 4 at the 9-position. Catalytic hydrogenation of the obtained 9-{2-[bis(isopropyloxy)phosphonylmethoxy]alkyl}-6-cyanopurines 9 and 10 followed by treatment with bromotrimethylsilane afforded the title compounds 11 and 12. Analogous acyclic nucleotides derived from purine-6-carboxamidines 14 were prepared from the cyanopurines 9a and 10a by treatment with sodium methoxide and ammonium chloride followed by deprotection. Compounds 11 and 12 exhibited moderate activity (MIC50 = 3-50 μg/ml) against herpes simplex virus type 1, varicella-zoster virus and Moloney murine sarcoma virus in vitro.
Theory of Tracer Exchange in Single-File Systems
Authors: Rödenbeck Christian , Kärger Jörg , Hahn Karsten
Published: July 2002

Tracer exchange in single-file systems (one-dimensional diffusional systems where the particles are not able to pass each other) shows peculiar and interesting features which differ considerably from that of transport diffusion or from the behaviour known from ordinary diffusional systems. A formalism relating the tracer exchange curve (as the observable of the tracer exchange experiment) to the residence time distribution (describing the intracrystalline diffusional mechanism) and the boundary condition (describing the situation outside) is introduced. The formalism is guite general and valid for any diffusional regime. Typical examples of the residence time distribution of a single-file system can be inferred from the tracer exchange curves obtained in a previous study by numerical simulations. Based on these examples, the tracer exchange curves for the single-file system subject to different boundary conditions (corresponding to a variety of experimental set-ups) are plotted and discussed.
Electrochemical Study of Acid-Base Properties of Some 2,5-Dihydro-1,3,4-thiadiazoles in Aqueous-Ethanolic Solutions
Authors: Turowska Maria , Mloston Grzegorz , Krzyczmonik Pawel , Raczak Jacek , Romanski Jaroslaw
Published: July 2002

The dissociation constants Ka for spherically crowded 2'- and 2,5-substituted thiadiazolines and their protonated forms in 45% (v/v) aqueous-ethanolic solutions (ionic strength m = 0.1) were determined using the pH-metric method. All the thiadiazoles are weak bases. Some of them showed also weak acidic properties. The formation enthalpies have been calculated using the MNDO method. On the basis of the obtained results the mechanism of the protonation process is discussed.
Reduction of 2-Nitro-5α-cholestan-3-one, Its Enol Tautomer and 2-Nitro-5α-cholest-2-en-3-amine Derivatives. Synthesis of Bis-Steroidal Pyrazines
Authors: Morzycki Jacek W. , Gryszkiewicz Agnieszka , Lotowski Zenon , Szczepek Wojciech J.
Published: July 2002

Reduction of 2α-nitro-5α-cholestan-3-one (4), its enol tautomer (3a) and 3-acetylamino-2-nitro-5α-cholest-2-ene (2) was studied. The latter compound was reduced with zinc in acetic acid to 3β-acetylamino-5α-cholestan-2-one (8). The similar reaction of 3a or 4 led to 2α-amino-5α-cholestan-3-one (11a), that may be trapped as N-formyl derivative. When crude 11a was subjected to air oxidation, pyrazino[2',3':2,3;5',6':2,3]bis(5α-cholestane) (9) was obtained.
Synthesis and Photochemical Trasformations of 19-Phenylsulfonyl Provitamin D Analogue
Authors: Grzegorzewski Piotr , Koladkiewicz Izabela , Morzycki Jacek W. , Sicinski Rafal R.
Published: July 2002

The synthesis of provitamin D analogue 19-(phenylsulfonyl)androsta-5,7-diene-3β,17β-diyl 3-acetate 17-pivalate (20) has been accomplished from 19-hydroxyandrost-5-ene-3β,17β-diyl 3-acetate 17-pivalate. 19-(Phenylsulfonyl)androst-5-ene-3β,17β-diyl 3-acetate 17-pivalate (10), a precursor of 20, was first obtained in low yield in the nucleophilic displacement reactions of 19-halogenated-5-ene steroids with sodium benzenesulfinate. Then a more efficient method has been used, which involves protection of the double bond as an epoxide. Introduction of the C(7)-C(8) double bond into olefin 10 has been also achieved in two ways. The first involved bromination-dehydrobromination and the other consisted of an allylic oxidation of olefin 10 leading to enone and the Bamford-Stevens reaction of its tosylhydrazone. UV irradiation of 5,7-diene 20 resulted in formation of a complex mixture of products. The structures of five isolated compounds were established on the basis of their 1H NMR spectra and mechanistic rationale.
NMR Assignments of [6-R-nido-5,6-C2B8H10]- Anions (where R = H, Me, and n-C6H13). An Irreversible 5 → 6 Alkyl Migration via a B9 Vertex-Swing Mechanism
Authors: Janoušek Zbyněk , Kaszynski Piotr , Kennedy John D. , Štíbr Bohumil
Published: July 2002

Deprotonation by "proton sponge" (PS = 1,8-dimethylaminonaphthalene) of the parent dicarbaborane nido-5,6-C2B8H12 (1) and its 6-R-substituted derivatives (where R = Me and n-C6H13) leads to the anions [nido-5,6-C2B8H11]- [1]- and [6-R-nido-5,6-C2B8H10]- [6-R-1]-, respectively. In contrast, the deprotonation of the 5-substituted isomers, 5-R-nido-5,6-C2B8H11 (5-R-1), results in irreversible conversion into the 6-substituted anions [6-R-1]-, from which the neutral compounds 6-R-1 can be obtained via reprotonation. This 5 → 6 alkyl migration can be explained by the B9 vertex-swing mechanism previously proposed for the interenantiomeric fluxionality of [1]-, but now with the product dictated by the higher thermodynamic stabilities of the 6-substituted derivatives. The work has also resulted in complete assignments of 11B and 1H NMR spectra of the [nido-5,6-C2B8H11]- anion and of 11B NMR spectra of the [6-R-nido-5,6-C2B8H10]- anions.
Building a Picture of Heteroborane Isomerisation: Synthesis and Characterisation of the 10-(Dialkyl- sulfane)-7,8-diphenyl-7,8-dicarba-nido-undecaboranes 7,8-Ph2-10-L-7,8-nido-C2B9H10 (L = SMe2, SMeEt, SEt2) and of Intermediate and Isomerised Products Arising from Metallation of the First of These
Authors: Dunn Shirley , Garrioch Rhona M. , Rosair Georgina M. , Smith Lorraine , Welch Alan J.
Published: July 2002

Three new, substituted, nido carboranes, 7,8-Ph2-10-(SMe2)-7,8-nido-C2B9H10 (1a), 7,8-Ph2-10- (SMeEt)-7,8-nido-C2B9H10 (1b) and 7,8-Ph2-10-(SEt2)-7,8-nido-C2B9H10 (1c) have been synthesised and characterised, including a crystallographic study of the first. Deprotonation of 1a followed by treatment with (MeCN)2(CO)2MoBr(η-C3H5) at 0 °C affords the non-icosahedral 1,2-Ph2-4-(SMe2)-5-(η-C3H5)-5,5-(CO)2-5,1,2-closo-MoC2B9H8 (2a), which on subsequent warming transforms into icosahedral 2,8-Ph2-5-(SMe2)-1-(η-C3H5)-1,1-(CO)2-1,2,8-closo- MoC2B9H8 (3a). It is argued that under the conditions of these rearrangements the B-S bond is likely to remain intact, and consequently that the identity of the SMe2-labelled boron atom in 3a affords useful experimental information on the course of the isomerisation.
Multivariate Regression with Substituent Shift Increments. IV. 2-(4-X-Phenyl)-1,3-dihydro-2H-isoindole-1,3-diones and 3-(4-X-Phenyl)-3,4-dihydro-2H-1,3-benzoxazine-2,4-diones
Authors: Holík Miroslav , Friedl Zdeněk , Waisser Karel , Gregor Jiří
Published: July 2002

Two series of para disubstituted benzenes were studied: 2-(4-X-phenyl)-1,3-dihydro- 2H-isoindole-1,3-diones (1) and 3-(4-X-phenyl)-3,4-dihydro-2H-1,3-benzoxazine-2,4-diones (2). Their 1H and 13C chemical shifts were correlated with substituent shift increments (SSI) aj and zj, respectively. For 13C chemical shifts, all four zj values, zi, zo, zm, and zp, were used to check the assignment and to find out possible variables for improvement of regression equations. Significant deviations from plain additivity were observed in the case of δH3 and δC3 chemical shifts. This can be explained by changes in diamagnetic anisotropy contribution induced by different twist of 4-substituent from the benzene plane caused by variable substituent in position 1.
Crystal Structures of Unusual Titanocene By-products from Attempted Dimerization of Terminal Alkynes
Authors: Gyepes Róbert , Císařová Ivana , Horáček Michal , Čejka Jiří , Petrusová Lidmila , Mach Karel
Published: July 2002

Structures of unusual organometallic products μ-[(1,2,3,3a,7a-η):(3a,4,5,6,7,7a-η)-4,7- bis(trimethylsilyl)indenyl]-di-μ-hydridobis(η5-cyclopentadienyl)titanium(TiIII/TiII) (9) and μ-[(3,4,5-η):(4,5,6-η)-(E,E)-2,2,7,7-tetramethylocta-3,5-diene}bis{bis(η5-methylcyclopentadienyl)titanium} (10a) were determined by X-ray diffraction analysis. Compounds 9 and 10a arose as by-products in very low yields in the Ti(C5H5)2(η2-Me3SiC≡CSiMe3)-HC≡CSiMe3 and Ti(C5H4Me)2(η2-Me3SiC≡CSiMe3)-HC≡CCMe3 systems, respectively, when exposed to sunlight. Mechanisms of their formation were tentatively discussed.
Transfer Thermodynamic Functions ∆Gt0, ∆Ht0 and T∆St0 of cis- and trans-[CoCl2(en)2]+ Isomers in Aqueous Mixtures of Methanol, tert-Butyl Alcohol and Acetonitrile
Authors: Vollárová Oľga , Benko Ján
Published: July 2002

The solubility, partial molar volume and standard integral molar enthalpy of solution of cis- and trans-[CoCl2(en)2]Cl in water, aqueous methanol, aqueous tert-butyl alcohol and aqueous acetonitrile are reported. The transfer functions ∆Gt0, ∆Ht0 and T∆St0 as well as partial molar volumes are used to obtain information on the solute-solvent interactions. Results obtained are discussed in terms of differences in the surface charge distribution in isomeric coordination species.
Theoretical Justification of the Different Stages of Transformation of 1(3,6)-Phenanthrena-4-(1,4)-benzenacyclohexaphane-2,5-diene to Coronene
Authors: Rioseras-Garcia Maria J. , Hernando-Huelmo Jose M.
Published: July 2002

A theoretical study of the molecule 1(3,6)-phenanthrena-4-(1,4)-benzenacyclohexaphane-2,5-diene and of all intermediates of its transformation to coronene has been preformed using the AM1 method. Geometric parameters of the compounds are compared with the goal of confirming the experimental reaction pathway. Possible interconversions of the most probable compounds are also explored.
The pathological status of exercise dependence
Authors: Bamber Diane , Cockerill Ian M , Carroll Douglas
Published: July 2002

Objectives—This study was concerned with the concept of exercise dependence. Levels of psychological morbidity, personality profiles, and exercise beliefs were compared among subjects screened for exercise dependence and eating disorders.

Method—Adult female exercisers were allocated on the basis of questionnaire screening to one of the following groups: primary exercise dependence (n = 43); secondary exercise dependence, where there was the coincidence of exercise dependence and an eating disorder (n = 27); eating disorder (n =14); control, where there was no evidence of either exercise dependence or eating disorder (n = 110). Questionnaire assessment was undertaken of psychological morbidity, self esteem, weight and body shape dissatisfaction, personality, and exercise beliefs.

Results—Aside from a higher incidence of reported menstrual abnormalities, the primary exercise dependence group was largely indistinguishable from the controls. In stark contrast, the secondary exercise dependence group reported higher levels of psychological morbidity, neuroticism, dispositional addictiveness, and impulsiveness, lower self esteem, greater concern with body shape and weight, as well as with the social, psychological, and aesthetic costs of not exercising than the controls, but differed little from the eating disorder group.

Conclusions—In the absence of an eating disorder, women identified as being exercise dependent do not exhibit the sorts of personality characteristics and levels of psychological distress that warrant the construction of primary exercise dependence as a widespread pathology.
Randomised, controlled walking trials in postmenopausal women: the minimum dose to improve aerobic fitness?
Authors: Asikainen T-M , Miilunpalo S , Oja P , Rinne M , Pasanen M , Uusi-Rasi K , Vuori I
Published: July 2002

Background:The American College of Sports Medicine recommends 20–60 minutes of aerobic exercise three to five days a week at an intensity of 40/50–85% of maximal aerobic power (Vo2max) reserve, expending a total of 700–2000 kcal (2.93–8.36 MJ) a week to improve aerobic power and body composition.

Objective:To ascertain the minimum effective dose of exercise.

Methods:Voluntary, healthy, non-obese, sedentary, postmenopausal women (n = 121), 48–63 years of age, were randomised to four low dose walking groups or a control group; 116 subjects completed the study. The exercise groups walked five days a week for 24 weeks with the following intensity (% of Vo2max) and energy expenditure (kcal/week): group W1, 55%/1500 kcal; group W2, 45%/1500 kcal; group W3, 55%/1000 kcal; group W4, 45%/1000 kcal. Vo2maxwas measured in a direct maximal treadmill test. Submaximal aerobic fitness was estimated as heart rates at submaximal work levels corresponding to 65% and 75% of the baseline Vo2max. The body mass index (BMI) was calculated and percentage of body fat (F%) estimated from skinfolds.

Results:The net change (the differences between changes in each exercise group and the control group) in Vo2maxwas 2.9 ml/min/kg (95% confidence interval (CI) 1.5 to 4.2) in group W1, 2.6 ml/min/kg (95% CI 1.3 to 4.0) in group W2, 2.4 ml/min/kg (95% CI 0.9 to 3.8) in group W3, and 2.2 ml/min/kg (95% CI 0.8 to 3.5) in group W4. The heart rates in standard submaximal work decreased 4 to 8 beats/min in all the groups. There was no change in BMI, but the F% decreased by about 1% unit in all the groups.

Conclusions:Walking (for 24 weeks) at moderate intensity 45% to 55% of Vo2max, with a total weekly energy expenditure of 1000–1500 kcal, improves Vo2maxand body composition of previously sedentary, non-obese, postmenopausal women. This dose of exercise apparently approaches the minimum effective dose.
Evidence based medicine in clinical practice: how to advise patients on the influence of age on the outcome of surgical anterior cruciate ligament reconstruction: a review of the literature
Authors: Sloane P A , Brazier H , Murphy A W , Collins T
Published: July 2002

Objective:To determine, using a literature search, whether patient age influences the outcome of surgical reconstruction of a torn anterior cruciate ligament.

Methods:Medline (1966 to present) was searched using the PubMed interface, Embase (1974 to present) using the Datastar system, and the Cochrane Library at the Update Software web site. Papers retrieved from the three databases were independently assessed by two reviewers using preliminary inclusion criteria. Reference lists of papers satisfying the preliminary criteria were then scanned and appropriate papers reviewed. Any new papers in turn had their reference lists scanned, this process continuing until no new papers were identified. Final inclusion criteria were then applied to all papers satisfying the preliminary inclusion criteria.

Results:The initial search identified 661 papers. Exclusion of duplicates produced 536 unique papers. Medline contained 445, Embase 185, and the Cochrane Library 31. Of the 536, 523 were assessed by abstract and 12 by full text; one paper was not retrieved. Application of the preliminary inclusion criteria produced 33 papers. Their reference lists contained 950 references. Scanning of these added six new papers to the dataset. These six had their reference lists assessed; no new papers were identified. Four of the 39 papers in the completed dataset satisfied the final inclusion criteria. There was wide variation in the total number of subjects in the four studies, ranging from 22 to 203 patients. The total number of different outcome measures was 17; only one measure was used by all four studies. None of the objective outcome measures showed any significant difference between age groups, and the subjective measures, which did show differences, were contradictory. A total of 108 interlibrary loans were requested, by a full time researcher, at a total cost of IR£432.00 over a 10 week period.

Conclusions:When advising patients on the outcome of anterior cruciate ligament reconstruction, age should not be considered in isolation. In the absence of relevant guidelines, meta-analyses, or systematic reviews, the application of evidence based medicine to clinical practice has significant resource implications.
Daily concentrations of air pollution and plasma fibrinogen in London
Authors: Pekkanen J , Brunner E J , Anderson H R , Tiittanen P , Atkinson R W
Published: July 2002

OBJECTIVES

The reason for the association between air pollution and risk of cardiovascular diseases is unknown. The hypothesis was examined that daily concentrations of air pollution are associated with daily concentrations of fibrinogen, a risk factor for cardiovascular disease.

METHODS

Data on concentrations of plasma fibrinogen for 4982 male and 2223 female office workers, collected in a cross sectional survey in London between September 1991 and May 1993, were combined with data on concentrations of air pollution during the day of blood sampling and during the 3 preceding days.

RESULTS

After adjustment for weather and other confounding factors, an increase in the 24 hour mean NO2during the previous day from the 10th to the 90th percentile (61.7 μg/m3) was associated with a 1.5% (95% confidence interval (95% CI) 0.4% to 2.5%) higher fibrinogen concentration. The respective increase for CO (1.6 mg/m3) was 1.5% (95% CI 0.5%, 2.5%). These associations tended to be stronger in the warm season (April to September). Significant associations were found for black smoke and particulate matter of diameter 10 μm (PM10) only in the warm season. No association with fibrinogen was found for SO2or ozone.

CONCLUSIONS

The short term association between air pollution, possibly from traffic, and risk of cardiovascular events may be at least partly mediated through increased concentrations of plasma fibrinogen, possibly due to an inflammatory reaction caused by air pollution.
Impairment of colour vision in workers exposed to organic solvents
Authors: Semple S , Dick F , Osborne A , Cherrie J W , Soutar A , Seaton A , Haites N
Published: July 2002

OBJECTIVES

To investigate loss of colour vision related to exposure to solvents and the role of three enzyme polymorphisms in modifying the risk in exposed workers.

METHODS

A sample was studied of 68 male dockyard workers and 42 male community controls with and without neuropsychological symptoms from a previous cross sectional study. Indices of cumulative and intensity based exposure to solvents were calculated for all subjects. Alcohol, drug, and smoking histories were obtained. Colour vision was tested by Lanthony D15d colour vision test. Genotype of glutathione S-transferase M1 and T1 and N-acetyltransferase 2 polymorphisms were determined.

RESULTS

The relation between impairment of colour vision and exposure to solvents was investigated with multiple regression techniques. Increasing annual exposure to solvents was significantly associated with reduced colour vision (p=0.029). Impairment of colour vision was not associated with neuropsychological symptoms as measured by the Q16 solvent symptom questionnaire. No significant association was found between acquired impairment of colour vision and genetic polymorphisms when GSTM1, GSTT1 or NAT2 phenotypes were included in the analyses.

CONCLUSIONS

Exposure to mixed solvents is associated with impairment in colour vision, the risk increases with increasing exposure. The risk of impairment of colour vision was not altered in this study by the presence of different GSTM1, GSTT1 or NAT2 polymorphisms.
Exposure to benzene in urban workers: environmental and biological monitoring of traffic police in Rome
Authors: Crebelli R , Tomei F , Zijno A , Ghittori S , Imbriani M , Gamberale D , Martini A , Carere A
Published: July 2002

OBJECTIVES

To evaluate the contribution of traffic fumes to exposure to benzene in urban workers, an investigation on personal exposure to benzene in traffic police from the city of Rome was carried out.

METHODS

The study was performed from December 1998 to June 1999. Diffusive Radiello personal samplers were used to measure external exposures to benzene and alkyl benzenes during the workshift in 139 policemen who controlled medium to high traffic areas and in 63 office police. Moreover, as biomarkers of internal exposure to benzene, blood benzene, and urinary trans, trans-muconic and S-phenyl mercapturic acids were measured at the beginning and at the end of the workshift in 124 traffic police and 58 office police.

RESULTS

Time weighted average (TWA) exposure to benzene was consistently higher among traffic police than among indoor workers (geometric mean 6.8 and 3.5 μg/m3, respectively). Among the traffic police, the distribution of individual exposures was highly asymmetric, skewed toward higher values. Mean ambient benzene concentrations measured by municipal air monitoring stations during workshifts of traffic police were generally higher (geometric mean 12.6 μg/m3) and did not correlat with personal exposure values. In particular, no association was found between highest personal exposure scores and environmental benzene concentrations. Among the exposure biomarkers investigated, only blood benzene correlated slightly with on-shift exposure to benzene, but significant increases in both urinary trans, trans-muconic and S-phenylmercapturic acids were found in active smokers compared with non-smokers, irrespective of their job.

CONCLUSION

The exposure to traffic fumes during working activities in medium to high traffic areas in Rome may give a relatively greater contribution to personal exposure to benzene than indoor sources present in confined environments. Smoking significantly contributed to internal exposure to benzene in both indoor and outdoor workers.
Syncope after effort
Authors: Lowe Martin D , Petch Michael C
Published: July 2002

A 29-year-old man developed recurrent syncope following exertion. Cardiac investigations revealed no evidence of structural heart disease, but during exercise testing, in the recovery phase, he sustained a bradycardia and then asystole for a prolonged period. Before cardiac massage could be instituted a tonic-clonic fit occurred, and this initiated a return to sinus rhythm. His symptoms were abolished following the implantation of a dual-chamber pacemaker.
Alcoholic liver disease
Authors: Walsh Kevin , Alexander Graeme
Published: July 2002

Alcohol is a major cause of liver cirrhosis in the Western world and accounts for the majority of cases of liver cirrhosis seen in district general hospitals in the UK. The three most widely recognised forms of alcoholic liver disease are alcoholic fatty liver (steatosis), acute alcoholic hepatitis, and alcoholic cirrhosis. The exact pathogenesis of alcoholic liver injury is still not clear but immune mediated and free radical hepatic injury are thought to be important. There is increasing interest in genetic factors predisposing to hepatic injury in susceptible individuals. Diagnosis is based on accurate history, raised serum markers such as γ-glutamyltransferase, mean corpuscular volume, and IgA and liver histology when obtainable. Abstinence is the most important aspect of treatment. Newer drugs such as acamprosate and naltrexone are used to reduce alcohol craving. Vitamin supplements and nutrition are vital while corticosteroids have a role in acute alcoholic hepatitis where there is no evidence of gastrointestinal haemorrhage or sepsis. Liver transplantation has excellent results in abstinent patients with end stage liver disease but there are concerns about recidivism after transplant.
Referral for autopsies: analysis of 651 consecutive deaths in one general practice
Authors: Khunti Kamlesh
Published: July 2002

Autopsies represent a key instrument in educating doctors and may aid quality assurance for primary and secondary care. This study shows that only a few patients have an autopsy, of which the majority are carried out at the request of the coroner for medicolegal reasons. Better education and communication between general practitioners, hospital clinicians, pathologists, and coroners may increase the rate of autopsies.
Single photon emission computed tomography in tuberculous meningitis
Authors: Misra U K , Kalita J , Das B K
Published: July 2002

Introduction

Data on single photon emission computed tomography (SPECT) in tuberculous meningitis are lacking and prompted this study. SPECT findings in tuberculous meningitis are reported and correlated with clinical and radiological findings.

Patients and Methods

Seventeen patients with tuberculous meningitis that was diagnosed on clinical, radiological, and laboratory criteria have been included. Their age ranged between 5 and 62 years and four of them were female. Computed tomography and/or magnetic resonance imaging (MRI) and SPECT using99mTc-ethylene cystine dimer were performed in all the patients. On the basis of Barthel index (BI) score the patients’ outcome was defined as complete (BI = 20), partial (BI = 19–12), and poor recovery (BI<12).

Result

Eleven patients were in stage III and three each in stage II and stage I tuberculous meningitis. Two patients had hemiplegia and five quadriplegia. Computed tomography was abnormal in 11 out of 16 patients and revealed hydrocephalus in nine, basal exudates, infarction in subcortical white matter and basal ganglia in six patients each, frontal cortical infarction in one, and granulomata in three patients. Cranial MRI was carried out in four patients and revealed multiple granulomata, hydrocephalus, and brainstem infarction in two patients each. SPECT studies were abnormal in all except two patients and revealed hypoperfusion of the basal ganglia in 14, cortical hypoperfusion in 10, and midbrain hypoperfusion in one patient. At the three month follow up four patients had died, five had poor, three partial, and five complete recovery. The SPECT studies were more frequently abnormal compared with computed tomography but did not correlate with stage of meningitis or outcome.

Conclusion

In tuberculous meningitis subcortical and cortical hypoperfusion is common but it does not correlate with stage of meningitis or three month outcome.
An unusual case of pyrexia of unknown origin with cervical lymphadenopathy
Authors: Wurm P , Townson G , Lauder I , Wicks A C
Published: July 2002

Kikuchi’s disease is usually a self limiting illness characterised by pyrexia, neutropenia, and cervical lymphadenopathy particularly in young women of Asian descent. This often leads to an initial misdiagnosis of lymphoma. A case of a young Asian woman who presented with pyrexia of unknown origin is described.
Disseminated fungal infection complicated with pulmonary haemorrhage in a case of acute myeloid leukaemia
Authors: Thulkar S , Sharma S , Das P K , Kumar L
Published: July 2002

Pulmonary haemorrhage is a common necropsy finding in acute leukaemia, however, it is rarely diagnosed during life. A man with acute myeloid leukaemia is reported who presented with disseminated fungal infection, anaemia, thrombocytopenia, and subconjuctival and petechial haemorrhages. During the course of the patient’s illness, the chest infection was complicated with bilateral pulmonary haemorrhage. The diagnosis of pulmonary haemorrhage was based on characteristic clinical and radiological findings. The patient improved on treatment.
Obstetric difficulties due to Graves' disease
Authors: Bhattacharyya A , Wright J D , Vice P A
Published: July 2002

A 14 year old girl was referred to the paediatricians with symptoms of hyperthyroidism. She had a smooth diffuse goitre with dysthyroid eye disease (proptosis, lid lag, and lid retraction). Hyperthyroidism was confirmed biochemically (protein bound iodine 18.8, normal 5–8 μg). She was treated with carbimazole, 30 mg/day. Poor compliance resulted in inpatient care for treatment with carbimazole followed by subtotal thyroidectomy, two years later. Two years later she presented with a self limited episode of hyperthyroidism. Aged 22 years she was referred with eight weeks amenorrhoea when pregnancy was confirmed and terminated. She was floridly hyperthyroid (free thyroxine 36.6, normal 10–23 pmol/l, free triiodothyronine 14, normal 3–9 pmol/l; thyroid stimulating hormone (TSH) undetectable, normal 0.5–5 mU/l). She was treated with carbimazole for nine months with apparently good clinical response.
Extended Matching Questions for the MRCS
Authors: London N J M
Published: July 2002

Extended matching questions now form roughly one third of the new MRCS examination. This revision book follows the STEP course closely with each chapter representing one of the 10 modules. The first five chapters deal with core modules and the last five with system modules. The authors have recently passed the MRCS examination and have based the questions in this book on the format and content of questions that they and their peers have recently met in the examination. Although the authors have undoubtedly collected together an excellent selection of extended matching questions, the real strength of the book lies in the answer sections. These sections clearly explain the rationale behind the correct answer and, importantly, discuss other relevant issues. The detailed discussion in the answers sections makes this book particularly useful for revision and many of the answers contain useful line drawings and tables.
Positive and negative effects of allochthonous dissolved organic matter and inorganic nutrients on phytoplankton growth
Authors: Klug Jennifer L
Published: July 2002

Dissolved organic matter (DOM) can have both positive and negative effects on phytoplankton growth. The magnitude of these effects may vary depending on the source of DOM and the composition of the phytoplankton community. Here, I address the relative importance of the positive and negative effects of DOM extracts on phytoplankton growth. In short-term experiments with phytoplankton from West Long Lake, a small, moderately coloured lake in northern Michigan, U.S.A., the net effect of doubling ambient DOM on phytoplankton growth was positive. Increasing DOM concentrations from ~10 mg C·L1to ~20 mg C·L1had a negative effect on total phytoplankton growth by reducing irradiance and thus reducing the depth to which growth was positive. However, inorganic nutrients in the DOM extracts increased growth at each irradiance level. The positive effect on phytoplankton growth owing to the nutrients associated with DOM was greater than the negative effect caused by shading. Although the positive effects of allochthonous DOM inputs outweighed the negative effects for the nutrient-limited phytoplankton in these experiments, the net effect depends on the concentration and availability of nutrients associated with allochthonous DOM as well as the physiological status of the phytoplankton community.