bluuebunny/crossref_metadata_2025 huggingface dataset:
Herpes Simplex Virus DNA Cleavage and Packaging Proteins Associate with the Procapsid prior to Its Maturation
Authors: Sheaffer Amy K. , Newcomb William W. , Gao Min , Yu Dong , Weller Sandra K. , Brown Jay C. , Tenney Daniel J.
Published: July 2002

Packaging of DNA into preformed capsids is a fundamental early event in the assembly of herpes simplex virus type 1 (HSV-1) virions. Replicated viral DNA genomes, in the form of complex branched concatemers, and unstable spherical precursor capsids termed procapsids are thought to be the substrates for the DNA-packaging reaction. In addition, seven viral proteins are required for packaging, although their individual functions are undefined. By analogy to well-characterized bacteriophage systems, the association of these proteins with various forms of capsids, including procapsids, might be expected to clarify their roles in the packaging process. While the HSV-1 UL6, UL15, UL25, and UL28 packaging proteins are known to associate with different forms of stable capsids, their association with procapsids has not been tested. Therefore, we isolated HSV-1 procapsids from infected cells and used Western blotting to identify the packaging proteins present. Procapsids contained UL15 and UL28 proteins; the levels of both proteins are diminished in more mature DNA-containing C-capsids. In contrast, UL6 protein levels were approximately the same in procapsids, B-capsids, and C-capsids. The amount of UL25 protein was reduced in procapsids relative to that in more mature B-capsids. Moreover, C-capsids contained the highest level of UL25 protein, 15-fold higher than that in procapsids. Our results support current hypotheses on HSV DNA packaging: (i) transient association of UL15 and UL28 proteins with maturing capsids is consistent with their proposed involvement in site-specific cleavage of the viral DNA (terminase activity); (ii) the UL6 protein may be an integral component of the capsid shell; and (iii) the UL25 protein may associate with capsids after scaffold loss and DNA packaging, sealing the DNA within capsids.
Fowlpox Virus Encodes a Novel DNA Repair Enzyme, CPD-Photolyase, That Restores Infectivity of UV Light-Damaged Virus
Authors: Srinivasan Viswanathan , Schnitzlein William M. , Tripathy Deoki N.
Published: July 2002

Fowlpox virus (FPV), a pathogen of poultry, can persist in desiccated scabs shed from infected hosts. Although the mechanisms which ensure virus survival are unknown, it is likely that some type of remedial action against environmentally induced damage is required. In this regard, we have identified an open reading frame (ORF) coding for a putative class II cyclobutane pyrimidine dimer (CPD)-photolyase in the genome of FPV. This enzyme repairs the UV light-induced formation of CPDs in DNA by using blue light as an energy source and thus could enhance the viability of FPV during its exposure to sunlight. Based on transcriptional analyses, the photolyase gene was found to be expressed late during the FPV replicative cycle. That the resultant protein retained DNA repair activity was demonstrated by the ability of the corresponding FPV ORF to complement functionally a photolyase-deficient
Escherichia coli
strain. Interestingly, insertional inactivation of the FPV photolyase gene did not impair the replication of such a genetically altered virus in cultured cells. However, greater sensitivity of this mutant than of the parental virus to UV light irradiation was evident when both were subsequently photoreactivated in the absence of host participation. Therefore, FPV appears to incorporate its photolyase into mature virions where the enzyme can promote their survival in the environment. Although expression of a homologous protein has been predicted for some chordopoxviruses, this report is the first to demonstrate that a poxvirus can utilize light to repair damage to its genome.
Identification of T-Cell Epitopes in Nonstructural Proteins of Foot-and-Mouth Disease Virus
Authors: Blanco Esther , Garcia-Briones Mercedes , Sanz-Parra Arantza , Gomes Paula , De Oliveira Eliandre , Valero Mari Luz , Andreu David , Ley Victoria , Sobrino Francisco
Published: July 2002

Porcine T-cell recognition of foot-and-mouth disease virus (FMDV) nonstructural proteins (NSP) was tested using in vitro lymphoproliferative responses. Lymphocytes were obtained from outbred pigs experimentally infected with FMDV. Of the different NSP, polypeptides 3A, 3B, and 3C gave the highest stimulations in the in vitro assays. The use of overlapping synthetic peptides allowed the identification of amino acid regions within these proteins that were efficiently recognized by the lymphocytes. The sequences of some of these antigenic peptides were highly conserved among different FMDV serotypes. They elicited major histocompatibility complex-restricted responses with lymphocytes from pigs infected with either a type C virus or reinfected with a heterologous FMDV. A tandem peptide containing the T-cell peptide 3A[21–35] and the B-cell antigenic site VP1[137–156] also efficiently stimulated lymphocytes from infected animals in vitro. Furthermore, this tandem peptide elicited significant levels of serotype-specific antiviral activity, a result consistent with the induction of anti-FMDV antibodies. Thus, inclusion in the peptide formulation of a T-cell epitope derived from the NSP 3A possessing the capacity to induce T helper activity can allow cooperative induction of anti-FMDV antibodies by B cells.
Oncolytic Activity of Vesicular Stomatitis Virus Is Effective against Tumors Exhibiting Aberrant p53, Ras, or Myc Function and Involves the Induction of Apoptosis
Authors: Balachandran Siddharth , Porosnicu Mercedes , Barber Glen N.
Published: July 2002

We have recently shown that vesicular stomatitis virus (VSV) exhibits potent oncolytic activity both in vitro and in vivo (S. Balachandran and G. N. Barber, IUBMB Life 50:135–138, 2000). In this study, we further demonstrated, in vivo, the efficacy of VSV antitumor action by showing that tumors that are defective in p53 function or transformed with
myc
or activated
ras
are also susceptible to viral cytolysis. The mechanism of viral oncolytic activity involved the induction of multiple caspase-dependent apoptotic pathways was effective in the absence of any significant cytotoxic T-lymphocyte response, and occurred despite normal PKR activity and eIF2α phosphorylation. In addition, VSV caused significant inhibition of tumor growth when administered intravenously in immunocompetent hosts. Our data indicate that VSV shows significant promise as an effective oncolytic agent against a wide variety of malignant diseases that harbor a diversity of genetic defects.
Evaluation of Interactions of Human Cytomegalovirus Immediate-Early IE2 Regulatory Protein with Small Ubiquitin-Like Modifiers and Their Conjugation Enzyme Ubc9
Authors: Ahn Jin-Hyun , Xu Yixun , Jang Won-Jong , Matunis Michael J. , Hayward Gary S.
Published: July 2002

The human cytomegalovirus (HCMV) major immediate-early protein IE2 is a nuclear phosphoprotein that is believed to be a key regulator in both lytic and latent infections. Using yeast two-hybrid screening, small ubiquitin-like modifiers (SUMO-1, SUMO-2, and SUMO-3) and a SUMO-conjugating enzyme (Ubc9) were isolated as IE2-interacting proteins. In vitro binding assays with glutathione
S
-transferase (GST) fusion proteins provided evidence for direct protein-protein interaction. Mapping data showed that the C-terminal end of SUMO-1 is critical for interaction with IE2 in both yeast and in vitro binding assays. IE2 was efficiently modified by SUMO-1 or SUMO-2 in cotransfected cells and in cells infected with a recombinant adenovirus expressing HCMV IE2, although the level of modification was much lower in HCMV-infected cells. Two lysine residues at positions 175 and 180 were mapped as major alternative SUMO-1 conjugation sites in both cotransfected cells and an in vitro sumoylation assay and could be conjugated by SUMO-1 simultaneously. Although mutations of these lysine residues did not interfere with the POD (or ND10) targeting of IE2, overexpression of SUMO-1 enhanced IE2-mediated transactivation in a promoter-dependent manner in reporter assays. Interestingly, many other cellular proteins identified as IE2 interaction partners in yeast two-hybrid assays also interact with SUMO-1, suggesting that either directly bound or covalently conjugated SUMO moieties may act as a bridge for interactions between IE2 and other SUMO-1-modified or SUMO-1-interacting proteins. When we investigated the intracellular localization of SUMO-1 in HCMV-infected cells, the pattern changed from nuclear punctate to predominantly nuclear diffuse in an IE1-dependent manner at very early times after infection, but with some SUMO-1 protein now associated with IE2 punctate domains. However, at late times after infection, SUMO-1 was predominantly detected within viral DNA replication compartments containing IE2. Taken together, these results show that HCMV infection causes the redistribution of SUMO-1 and that IE2 both physically binds to and is covalently modified by SUMO moieties, suggesting possible modulation of both the function of SUMO-1 and protein-protein interactions of IE2 during HCMV infection.
Suboptimal Nucleotides in the Infectious, Pathogenic Simian Immunodeficiency Virus Clone SIVmac239
Authors: Alexander Louis , Denekamp Lynn , Czajak Susan , Desrosiers Ronald C.
Published: July 2002

We analyzed virus sequences in two monkeys infected with SIVmac239 and two monkeys infected with SHIVnef that maintained high, persisting viral loads. Sequence changes were observed consistently at four loci in all four animals: a single nucleotide change in the Lys-tRNA primer binding site in the 5′ long terminal repeat; two nucleotide changes that resulted in two amino acid changes in the
pol
gene product; and a single nucleotide change in the region of the simian immunodeficiency virus genome where the
rev
and
env
genes overlap, resulting in changes in the predicted amino acid sequences of both gene products. None of these mutations were seen in short-term cultures of CEM×174 cells infected with SIVmac239 or SHIVnef. At all four positions in all four animals, the new sequences represented consensus sequences for primate lentiviruses, whereas the inoculum sequences at these four loci have either never been or rarely been reported outside of SIVmac239. Thus, although cloned SIVmac239 is consistently pathogenic and consistently induces high viral load set points, it is clearly less than optimal at these four nucleotide positions.
Pestivirus Internal Ribosome Entry Site (IRES) Structure and Function: Elements in the 5′ Untranslated Region Important for IRES Function
Authors: Fletcher Simon P. , Jackson Richard J.
Published: July 2002

The importance of certain structural features of the 5′ untranslated region of classical swine fever virus (CSFV) RNA for the function of the internal ribosome entry site (IRES) was investigated by mutagenesis followed by in vitro transcription and translation. Deletions made from the 5′ end of the CSFV genome sequence showed that the IRES boundary was close to nucleotide 65: thus, the IRES includes the whole of domain II but no sequences upstream of this domain. Deletions which invaded domain II even to a small extent reduced activity to about 20% that of the full-length structure, and this 20% residual activity persisted with more extensive deletions until the whole of domain II had been removed and the deletions invaded the pseudoknot, whereupon IRES activity fell to zero. The importance of both stems of the pseudoknot was verified by making mutations in both sides of each stem; this severely reduced IRES activity, but the compensating mutations which restored base pairing caused almost full IRES function to be regained. The importance of the length of the loop linking the two stems of the pseudoknot was demonstrated by the finding that a reduction in length from the wild-type AUAAAAUU to AUU almost completely abrogated IRES activity. Random A→U substitutions in the wild-type sequence showed that IRES activity was fairly proportional to the number of A residues retained in this pseudoknot loop, with a preference for clustered neighboring A residues rather than dispersed As. Finally, it was found that the sequence of the highly conserved domain IIIa loop is, rather surprisingly, not important for the maintenance of full IRES activity, although amputation of the entire domain IIIa stem and loop was highly debilitating. These results are interpreted in the light of recent models, derived from cryo-electron microscopy, of the interaction of the closely related hepatitis C virus IRES with 40S ribosomal subunits.
Rapid Directional Translocations in Virus Replication
Authors: Willard Mark
Published: July 2002

By viewing virus development in real time, the experiments reported here reveal novel processes—rapid directional translocations—that are likely to be important elements of virus replication. Herpes simplex virus type 1 (HSV-1) was labeled by the fusion of the green fluorescent protein to a structural protein of its tegument (VP11/12), the product of gene UL46. Infection of cultured cells with this recombinant virus (GHSV-UL46) produced fluorescent particles that were distributed throughout the cytoplasm with concentrations in the perinuclear region; they were absent from the nucleus. Viewing infected cells in real time by means of video microscopy produced a novel dynamic picture of virus development. Most strikingly, some of the fluorescent particles exhibited extremely rapid directional translocations at velocities as great as 5 μm/s. The trajectories and destinations of these particles suggest that the rapid directional translocations serve at least three functions: the rapid transport of viral components to and between cytoplasmic processing stations, the delivery of materials for functions specific to the perinuclear region, and the conveyance of maturing virus particles to the plasma membrane. These rapid directional translocations are novel elements of virus assembly that are likely to be critical for efficient replication.
Measles Virus Spreads in Rat Hippocampal Neurons by Cell-to-Cell Contact and in a Polarized Fashion
Authors: Ehrengruber Markus U. , Ehler Elisabeth , Billeter Martin A. , Naim Hussein Y.
Published: July 2002

Measles virus (MV) can infect the central nervous system and, in rare cases, causes subacute sclerosing panencephalitis, characterized by a progressive degeneration of neurons. The route of MV transmission in neurons was investigated in cultured rat hippocampal slices by using MV expressing green fluorescent protein. MV infected hippocampal neurons and spread unidirectionally, in a retrograde manner, from CA1 to CA3 pyramidal cells and from there to the dentate gyrus. Spreading of infection depended on cell-to-cell contact and occurred without any detectable release of infectious particles. The role of the viral proteins in the retrograde MV transmission was determined by investigating their sorting in infected pyramidal cells. MV glycoproteins, the fusion protein (F) and hemagglutinin (H), the matrix protein (M), and the phosphoprotein (P), which is part of the viral ribonucleoprotein complex, were all sorted to the dendrites. While M, P, and H proteins remained more intracellular, the F protein localized to prominent, spine-type domains at the surface of infected cells. The detected localization of MV proteins suggests that local microfusion events may be mediated by the F protein at sites of synaptic contacts and is consistent with a mechanism of retrograde transmission of MV infection.
The Human Papillomavirus Type 31 Late 3′ Untranslated Region Contains a Complex Bipartite Negative Regulatory Element
Authors: Cumming Sarah A. , Repellin Claire E. , McPhillips Maria , Radford Jonathan C. , Clements J. Barklie , Graham Sheila V.
Published: July 2002

The papillomavirus life cycle is tightly linked to epithelial cell differentiation. Production of virus capsid proteins is restricted to the most terminally differentiated keratinocytes in the upper layers of the epithelium. However, mRNAs encoding the capsid proteins can be detected in less-differentiated cells, suggesting that late gene expression is controlled posttranscriptionally. Short sequence elements (less than 80 nucleotides in length) that inhibit gene expression in undifferentiated epithelial cells have been identified in the late 3′ untranslated regions (UTRs) of several papillomaviruses, including the high-risk mucosal type human papillomavirus type 16 (HPV-16). Here we show that closely related high-risk mucosal type HPV-31 also contains elements that can act to repress gene expression in undifferentiated epithelial cells. However, the HPV-31 negative regulatory element is surprisingly complex, comprising a major inhibitory element of approximately 130 nucleotides upstream of the late polyadenylation site and a minor element of approximately 110 nucleotides mapping downstream. The first 60 nucleotides of the major element have 68% identity to the negative regulatory element of HPV-16, and these elements bind the same cellular proteins, CstF-64, U2AF
65
, and HuR. The minor inhibitory element binds some cellular proteins in common with the major inhibitory element, though it also binds certain proteins that do not bind the upstream element.
Host-Specific Involvement of the HC Protein in the Long-Distance Movement of Potyviruses
Authors: Sáenz Pilar , Salvador Beatriz , Simón-Mateo Carmen , Kasschau Kristin D. , Carrington James C. , García Juan Antonio
Published: July 2002

Plum pox virus(PPV) is a member of thePotyvirusgenus that, in nature, infects trees of thePrunusgenus. Although PPV infects systemically several species of theNicotianagenus, such asN. clevelandiiandN. benthamiana, and replicates in the inoculated leaves ofN. tabacum, it is unable to infect systemically the last host. The long-distance movement defect of PPV was corrected in transgenic tobacco plants expressing the 5"-terminal region of the genome of tobacco etch virus (TEV), a potyvirus that infects systemically tobacco. The fact that PPV was unable to move to upper noninoculated leaves in tobacco plants transformed with the same TEV transgene, but with a mutation in the HC protein (HC-Pro)-coding sequences, identifies the multifunctional HC-Pro as the complementing factor, and strongly suggests that a defect in an HC-Pro activity is responsible for the long-distance movement defect of PPV in tobacco. Whereas PPV HC-Pro strongly intensifies the symptoms caused by potato virus X (PVX) in the PPV systemic hostsN. clevelandiiandN. benthamiana, it has no apparent effect on PVX pathogenicity in tobacco, supporting the hypothesis that long-distance movement and pathogenicity enhancement are related activities of the potyviral HC proteins. The movement defect of PPV in tobacco could also be complemented by cucumber mosaic virus in a mixed infection, demonstrating that at least some components of the long-distance machinery of the potyviruses are not strictly virus specific. A general conclusion of this work is that the HC-Pro might be a relevant factor for controlling the host range of the potyviruses.
Human Cytomegalovirus Major Immediate-Early Proteins and Simian Virus 40 Large T Antigen Can Inhibit Apoptosis through Activation of the Phosphatidylinositide 3′-OH Kinase Pathway and the Cellular Kinase Akt
Authors: Yu Yongjun , Alwine James C.
Published: July 2002

The temperature-sensitive cell linets13 is mutated in CCG1, the gene encoding TAFII250, the largest of the TATA-binding protein-associated factors (TAFs) in TFIID. At the nonpermissive temperature, the temperature-sensitive phenotypes are (i) transcription defects, (ii) cell cycle arrest in G1, and (iii) apoptosis. We previously demonstrated that the human cytomegalovirus (HCMV) major immediate-early proteins (MIEPs) can rescue the transcription defects and inhibit apoptosis at the nonpermissive temperature. In the work presented, we show that activation of the cellular kinase Akt alone can inhibit apoptosis ints13 cells grown at the nonpermissive temperature. More significantly, we show that the HCMV MIEPs can activate Akt, resulting in the inhibition of apoptosis. In parallel experiments, we found that simian virus 40 (SV40) large T antigen can mediate the same function. These experiments were done by transfecting the HCMV major immediate-early gene or a cDNA encoding T antigen intots13 cells, and thus neither viral attachment to receptors, viral tegument proteins, nor any other viral protein is required for Akt activation. Akt is activated by the phosphatidylinositide 3′-OH (PI3) kinase pathway. Using a specific inhibitor of PI3 kinase, we show that the ability of the MIEPs and T antigen to activate Akt and inhibit apoptosis is eliminated, suggesting that the viral proteins utilize the PI3 kinase pathway for Akt activation. Transfection of plasmids which express the individual 86-kDa (IEP86; IE2579aa) and 72-kDa (IEP72; IE1491aa) MIEPs indicate that each MIEP could inhibit apoptosis via activation of the PI3 kinase pathway.
Role of N-Linked Glycans in a Human Immunodeficiency Virus Envelope Glycoprotein: Effects on Protein Function and the Neutralizing Antibody Response
Authors: Quiñones-Kochs Miriam I. , Buonocore Linda , Rose John K.
Published: July 2002

The envelope (Env) glycoprotein of human immunodeficiency virus (HIV) contains 24 N-glycosylation sites covering much of the protein surface. It has been proposed that one role of these carbohydrates is to form a shield that protects the virus from immune recognition. Strong evidence for such a role for glycosylation has been reported for simian immunodeficiency virus (SIV) mutants lacking glycans in the V1 region of Env (J. N. Reitter, R. E. Means, and R. C. Desrosiers, Nat. Med. 4:679-684, 1998). Here we used recombinant vesicular stomatitis viruses (VSVs) expressing HIV Env glycosylation mutants to determine if removal of carbohydrates in the V1 and V2 domains affected protein function and the generation of neutralizing antibodies in mice. Mutations that eliminated one to six of the sites for N-linked glycosylation in the V1 and V2 loops were introduced into a gene encoding the HIV type 1 primary isolate 89.6 envelope glycoprotein with its cytoplasmic domain replaced by that of the VSV G glycoprotein. The membrane fusion activities of the mutant proteins were studied in a syncytium induction assay. The transport and processing of the mutant proteins were studied with recombinant VSVs expressing mutant Env G proteins. We found that HIV Env V1 and V2 glycosylation mutants were no better than wild-type envelope at inducing antibodies neutralizing wild-type Env, although an Env mutant lacking glycans appeared somewhat more sensitive to neutralization by antibodies raised to mutant or wild-type Env. These results indicate significant differences between SIV and HIV with regard to the roles of glycans in the V1 and V2 domains.
Immunodominance in Virus-Induced CD8+T-Cell Responses Is Dramatically Modified by DNA Immunization and Is Regulated by Gamma Interferon
Authors: Rodriguez Fernando , Harkins Stephanie , Slifka Mark K. , Whitton J. Lindsay
Published: July 2002

The phenomenon whereby the host immune system responds to only a few of the many possible epitopes in a foreign protein is termed immunodominance. Immunodominance occurs not only during microbial infection but also following vaccination, and clarification of the underlying mechanism may permit the rational design of vaccines which can circumvent immunodominance, thereby inducing responses to all epitopes, dominant and subdominant. Here, we show that immunodominance affects DNA vaccines and that the effects can be avoided by the simple expedient of epitope separation. DNA vaccines encoding isolated dominant and subdominant epitopes induce equivalent responses, confirming a previous demonstration that coexpression of dominant and subdominant epitopes on the same antigen-presenting cell (APC) is central to immunodominance. We conclude that multiepitope DNA vaccines should comprise a cocktail of plasmids, each with its own epitope, to allow maximal epitope dispersal among APCs. In addition, we demonstrate that subdominant responses are actively suppressed by dominant CD8+T-cell responses and that gamma interferon (IFN-γ) is required for this suppression. Furthermore, priming of CD8+T cells to a single dominant epitope results in strong suppression of responses to other normally dominant epitopes in immunocompetent mice, in effect rendering these epitopes subdominant; however, responses to these epitopes are increased 6- to 20-fold in mice lacking IFN-γ. We suggest that, in agreement with our previous observations, IFN-γ secretion by CD8+T cells is highly localized, and we propose that its immunosuppressive effect is focused on the APC with which the dominant CD8+T cell is in contact.
The Crystal and Molecular Structure of sym-fac-(1,4,7-Triazaheptane)-(S)-aspartatocobalt(III) Diperchlorate Dihydrate
Authors: Ondráček Jan , Ondráčková Jana , Maixner Jaroslav , Jursík František
Published: July 2002

The crystal and molecular structure of s-fac-[Co((S)-Asp)(dien)]ClO4 . HClO4 .2 H2O (dien = 1,4,7-triazaheptane) was solved by the heavy atom method. The position parameters of the non-hydrogen atoms and their anisotropic temperature parameters were refined based on 1 726 observed reflections with a final value of R = 0.073. The substance crystallizes in the orthorhombic system in the space group P212121, Z = 4, a = 8.506(1), b = 17.171(2), c = 13.277(1) Å. The structure involves hydrogen bonds between the O2, O4 and HN2 atoms of aspartic acid and the two molecules of water. The five-membered dien chelate rings take the asymmetric envelope conformations. The five-membered ring of (S)-aspartic acid possesses the symmetric envelope conformation whereas the six-membered ring exhibits the skew boat conformation.
Voltammetric Studies of Some Novel Fe(III) Complexes with Quadridentate Ligands. The Axial Ligand-Exchange Reactions in DMF and DMSO
Authors: Jovanovic Ljiljana S. , Bjelica Luka J.
Published: July 2002

The electrochemistry of four novel Fe(III) complexes of the type [Fe(L)Cl], involving quadridentate ligands based on the condensation products of benzoylacetone-S-methylisothiosemicarbazone with salicylaldehyde, 5-chlorosalicylaldehyde, 3,5-dichlorosalicylaldehyde or 5-nitrosalicylaldehyde, was studied in DMF and DMSO at a GC electrode. All complexes undergo a two-step one-electron reductions, usually complicated by chemical reactions. In solutions containing Cl-, the ligand-exchange reactions Cl--DMF and Cl--DMSO take place. Stability of the chloride-containing complexes was discussed in terms of the coordinated ligand effect, oxidation state of the central atom and, in particular, of the donor effect of the solvent. Some relevant kinetic data were calculated.
trans-4-Stilbenecarboxylatoalkylpentaamminecobalt(III) Perchlorates: Synthesis and Intramolecular Energy Transfer
Authors: Párkányi Cyril , Yeh Huang Lois Shiow-Chyn , Chu Sung Gun , Jeffries III Alfred T.
Published: July 2002

Three homologs of trans-4-stilbenecarboxylic acid, viz., trans-4-stilbeneacetic acid (18), β-(trans-4-stilbene)propionic acid (19), and γ-(trans-4-stilbene)butyric acid (20) were synthesized and, together with the parent trans-4-stilbenecarboxylic acid, used to obtain the corresponding [ω-(trans-4-stilbene)carboxylatoalkylpentaamminecobalt(III) complexes, [(PhCH=CHC6H4(CH2)nCOO)Co(NH3)5]2+ (1-4), where n = 0, 1, 2, or 3. Fluorescence studies suggest that an intramolecular excitation energy transfer occurs from the first excited singlet state of the ligand to the metal giving rise to a charge-transfer triplet-excited state of the complex, based on the analogy with previous work on complex 1. The efficiency of the energy transfer seems to decrease with increasing number of the methylene groups in the ligand.
Mass Transfer in Catalyst Particles of Non-Traditional Shape
Authors: Hanika Jiří , Dropka Natasha , Kubíček Milan
Published: July 2002

The numerical solution of a system of partial differential equations describing the reacting component transfer in catalyst particles of non-traditional shapes, in extrudates of the starcat and starring types, facilitates the concept of concentration field in a catalyst and of the effectiveness factor of internal diffusion which determines the total reaction rate and thus the catalyst performance. The problem solution was carried out for the first-order reaction of infinite long extrudate and for the particles of star-shaped catalyst of finite length. The favourable effect was confirmed of the catalyst extrudate shaping on its performance as far as the rection takes place in the diffusion region.
Syntheses and Crystal Structures of Dichlorobis[tetramethyl(phenyl)cyclopentadienyl]titanium(IV) and Chlorobis[tetramethyl(phenyl)cyclopentadienyl]titanium(III)
Authors: Horáček Michal , Polášek Miroslav , Kupfer Volkmar , Thewalt Ulf , Mach Karel
Published: July 2002

Dichlorobis[η5-tetramethyl(phenyl)cyclopentadienyl]titanium(IV) (1) and chlorobis[η5-tetramethyl- (phenyl)cyclopentadienyl]titanium(III) (2) were prepared by the generally known procedures. The X-ray crystal structures of 1 and 2 showed nearly identical Ti-CE (CE - centroid of the cyclopentadienyl ring) and Ti-Cl distances, the CE-Ti-CE angles and dihedral angles between least-squares planes of the cyclopentadienyl rings to those in [(C5Me5)2TiCl2] and [(C5Me5)2TiCl], respectively. ESR spectra of 2 in 2-methyltetrahydrofuran (MTHF) solutions and glasses revealed that 2 coordinates MTHF to give [(C5Me4Ph)2Ti(Cl)(MTHF)] (2a). The formation of 2a in MTHF solution is completed by lowering temperature to 205 K. A comparison with the known data gives the following order of affinity of [(C5Me4R)2TiCl] towards MTHF: Ph > SiMe3 > H > Me.
Stereoconservative Cyanation of [1,1'-Binaphthalene]-2,2'-dielectrophiles. An Alternative Approach to Homochiral C2-Symmetric [1,1'-Binaphthalene]-2,2'-dicarbonitrile and Its Transformations
Authors: Kasák Peter , Putala Martin
Published: July 2002

The performed study on the cyanation of [1,1'-binaphthalene]-2,2'-diiodide and [1,1'-binaph- thalene]-2,2'-diyl ditriflate showed reactions with zinc cyanide catalyzed by palladium phosphane complex in DMF to be the most effective procedures with almost complete conservation of stereogenic information - affording corresponding highly enantiomerically enriched dinitrile (from diiodide: 94% yield, 92% ee). Dinitrile was successfully transformed into [1,1'-binaphthalene]-2,2'-dicarboxylic acid and -2,2'-dicarbaldehyde in high yields (84-87%).
Immune function in female elite rowers and non-athletes
Authors: Nieman David C , Nehlsen-Cannarella Sandra L , Fagoaga Omar R , Henson Dru A , Shannon Michael , Hjertman Jannica M E , Schmitt Robert L , Bolton Marc R , Austin Melanie D , Schilling Brian K , Thorpe Richard
Published: July 2002

Objective—To compare immune function in female rowers and controls in the resting state, and then correlate the results with a two month history of upper respiratory tract infection (URTI).

Methods—Subjects included 20 elite female rowers located at the ARCO Olympic Training Centre in Chula Vista, California, and 19 non-athletic female controls. These two groups were compared cross sectionally for immune function and infection rates.

Results—Granulocyte/monocyte phagocytosis, oxidative burst activity, and plasma cytokine concentrations (interleukin-6, tumour necrosis factor-α, and interleukin-1 receptor antagonist) did not differ significantly between groups. Phytohaemagglutinin induced lymphocyte proliferative response (adjusted whole blood method) was significantly higher (31% and 36% for optimal and suboptimal concentrations respectively) in rowers than in controls. Natural killer cell activity was substantially higher (1.6-fold for total lytic units) in the female rowers than in controls. Two month health logs disclosed 5.2 (1.2) and 3.3 (1.1) days with URTI symptoms for the rowers and controls respectively (p = 0.268). For all 39 subjects combined, and for the 20 rowers separately, none of the immune parameters correlated significantly with number of days with URTI symptoms.

Conclusions—In this cross sectional comparison of elite female rowers and non-athletes, a group difference was found for natural killer cell activity and phytohaemagglutinin induced proliferative response (whole blood technique), but not other measures of immune function. The number of days with URTI symptoms during the spring season did not differ between groups, and variations in blood measures of immunity were unrelated to URTI.
Effects of endurance training on the isocapnic buffering and hypocapnic hyperventilation phases in professional cyclists
Authors: Chicharro José L , Hoyos Jesús , Lucía Alejandro
Published: July 2002

Objectives—To evaluate the changes produced in both the isocapnic buffering and hypocapnic hyperventilation (HHV) phases of professional cyclists (n = 11) in response to endurance training, and to compare the results with those of amateur cyclists (n = 11).

Methods—Each professional cyclist performed three laboratory exercise tests to exhaustion during the active rest (autumn: November), precompetition (winter: January), and competition (spring: May) periods of the sports season. Amateur cyclists only performed one exercise test during the competition period. The isocapnic buffering and HHV ranges were calculated during each test and defined as Vo2and power output (W).

Results—No significant differences were found in the isocapnic buffering range in each of the periods of the sports season in professional cyclists. In contrast, there was a significant reduction in the HHV range (expressed in W) during both the competition (p<0.01) and precompetition(p<0.05) periods compared with the rest period. On the other hand, a longer HHV range (p<0.01) was observed in amateur cyclists than in professional cyclists (whether this was expressed in terms of Vo2or W).

Conclusions—No change is observed in the isocapnic buffering range of professional cyclists throughout a sports season despite a considerable increase in training loads and a significant reduction in HHV range expressed in terms of power output.
Broken arm wrestler: Figure 1
Authors: Khashaba A
Published: July 2002

An unusual injury following an arm wrestle is presented, that of a fractured humerus.
The association football medical research programme: an audit of injuries in professional football
Authors: Hawkins R D , Hulse M A , Wilkinson C , Hodson A , Gibson M
Published: July 2002

Objectives—To undertake a prospective epidemiological study of the injuries sustained in English professional football over two competitive seasons.

Methods—Player injuries were annotated by club medical staff at 91 professional football clubs. A specific injury audit questionnaire was used together with a weekly form that documented each club's current injury status.

Results—A total of 6030 injuries were reported over the two seasons with an average of 1.3 injuries per player per season. The mean (SD) number of days absent for each injury was 24.2 (40.2), with 78% of the injuries leading to a minimum of one competitive match being missed. The injury incidence varied throughout the season, with training injuries peaking during July (p<0.05) and match injuries peaking during August (p<0.05). Competition injuries represented 63% of those reported, significantly (p<0.01) more of these injuries occurring towards the end of both halves. Strains (37%) and sprains (19%) were the major injury types, the lower extremity being the site of 87% of the injuries reported. Most injury mechanisms were classified as being non-contact (58%). Re-injuries accounted for 7% of all injuries, 66% of these being classified as either a strain or a sprain. The severity of re-injuries was greater than the initial injury (p<0.01).

Conclusions—Professional football players are exposed to a high risk of injury and there is a need to investigate ways of reducing this risk. Areas that warrant attention include the training programmes implemented by clubs during various stages of the season, the factors contributing to the pattern of injuries during matches with respect to time, and the rehabilitation protocols employed by clubs.
Utilisation of erythrocyte 6-thioguanine metabolite levels to optimise azathioprine therapy in patients with inflammatory bowel disease
Authors: Cuffari C , Hunt S , Bayless T
Published: July 2002

BACKGROUND AND AIM

The immunosuppressive properties of 6-mercaptopurine and its parent compound azathioprine are mediated by their intracellular metabolism into active 6-thioguanine (6-TG) metabolites. Measurement of erythrocyte 6-TG metabolite levels has been proposed as a useful clinical tool for assessing treatment efficacy in patients with inflammatory bowel disease (IBD).

AIM

The purpose of the study was to establish a therapeutic index of treatment efficacy based on measurement of erythrocyte 6-TG metabolite levels, and apply it clinically to guide therapy.

METHODS

Heparinised blood was obtained from 82 adult patients with IBD on long term (more than three months) antimetabolite therapy (63 Crohn's disease; 19 ulcerative colitis). Erythrocyte 6-TG metabolite levels were measured using reverse phase high performance chromatography, and correlated with treatment efficacy. In 22 patients with refractory Crohn's disease despite long term azathioprine therapy, their dosage was increased by 25 mg/day at eight week intervals as needed. Serial erythrocyte 6-TG metabolite levels were measured at each clinic visit and correlated with treatment efficacy.

RESULTS

Clinical remission, as defined by a low disease index score in patients weaned off or on a low alternate day dose (<20 mg on alternate days) of corticosteroid, was achieved in 68% of patients on long term antimetabolite therapy. Treatment efficacy correlated with erythrocyte 6-TG levels greater than 250 pmol/8×108 red blood cells in patients with colonic and fistulising Crohn's disease (p<0.01) but not in patients with ileocolonic disease. Eighteen of 22 patients with incompletely responsive Crohn's disease achieved disease remission by optimising their dose of azathioprine therapy. Median (range) erythrocyte 6-TG metabolite levels increased from 194 (67–688) to 303 (67–737) pmol/8×108 red blood cells (p<0.05). Clinical response associated well with a reduction in corticosteroid requirements. Mean (SEM) white blood cell count decreased from 8.6 (0.9) to 6.9 (0.6) ×103/μl with adjustment in azathioprine dosage. No patient incurred azathioprine induced leucopenia.

CONCLUSION

Measurement of erythrocyte 6-TG metabolite levels is helpful in determining the adequacy of azathioprine dosage and can be used to optimise the dose of antimetabolite therapy to achieve an improved clinical response without inducing leucopenia. Patients who are clinically refractory to azathioprine therapy despite achieving high erythrocyte 6-TG levels (>250) should be considered for adjunct or alternative forms of immunosuppressive therapy or surgery.
Jaundice in non-cirrhotic primary biliary cirrhosis: the premature ductopenic variant
Authors: Vleggaar F P , van Buuren H R , Zondervan P E , ten Kate F J W , Hop W C J ,   the Dutch Multicentre PBC study group
Published: July 2002

The clinical and pathological findings of four females with primary biliary cirrhosis (PBC) with an unusual and hitherto not well recognised course are reported. Patients suffered severe pruritus and weight loss with progressive icteric cholestasis which did not respond to such treatments as ursodeoxycholic acid and immunosuppressives. In all cases liver histology revealed marked bile duct loss without however significant fibrosis or cirrhosis. Further diagnostic studies and repeat biopsies confirmed the absence of liver cirrhosis as well as other potential causes of hyperbilirubinaemia. Comparison of the fibrosis-ductopenia relationship for our cases with that for a group of 101 non-cirrhotic PBC patients indicated that in the former the severity of bile duct loss relative to the amount of fibrosis was significantly higher. The proportion of portal triads containing an interlobular bile duct was 3%, 4%, 6%, and 10% compared with 45% (median; range 8.3–100%) for controls (p<0.001). Three patients received a liver transplant 6–7 years after the first manifestation of PBC because of progressive cholestasis, refractory pruritus, and weight loss, while the fourth patient is considering this option. In one case cirrhosis had developed at the time of transplantation while the others still had non-cirrhotic disease. These cases suggest that cholestatic jaundice in non-cirrhotic PBC may be secondary to extensive “premature” or accelerated intrahepatic bile duct loss. Although the extent of fibrosis may be limited initially, progression to cirrhosis appears to be inevitable in the long run. Despite intact protein synthesis and absence of cirrhotic complications, liver transplantation in the pre-cirrhotic stage for preventing malnutrition and to improve quality of life should be considered for these patients.
Views of the person with dementia
Authors: Hughes Julian C
Published: July 2002

In this paper I consider, in connection with dementia, two views of the person. One view of the person is derived from Locke and Parfit. This tends to regard the person solely in terms of psychological states and his/her connections. The second view of the person is derived from a variety of thinkers. I have called it the situated-embodied-agent view of the person. This view, I suggest, more readily squares with the reality of clinical experience. It regards the person as embedded in a history and culture. The human person is also an embodied agent. I contend that this view encourages a more appropriate approach towards the ethical issues that arise in dementia and towards people with dementia.
Equity - some theory and its policy implications
Authors: Culyer Anthony J
Published: July 2002

This essay seeks to characterise the essential features of an equitable health care system in terms of the classical Aristotelian concepts of horizontal and vertical equity, the common (but ill-defined) language of “need” and the economic notion of cost-effectiveness as a prelude to identifying some of the more important issues of value that policy-makers will have to decide for themselves; the characteristics of health (and what determines it) that can cause policy to be ineffective (or have undesired consequences); the information base that is required to support a policy directed at securing greater equity, and the kinds of research (theoretical and empirical) that are needed to underpin such a policy.
Fungal and other spore counts as predictors of admissions for asthma in the Trent region
Authors: Newson R , Strachan D , Corden J , Millington W
Published: July 2002

OBJECTIVES

The importance of airborne fungal and other spores in provoking asthma attacks is uncertain. Panel studies have generated evidence that suggests a link between outdoor spore counts and severity of asthma. There have been no population based time series studies relating outdoor exposure to spores with incidence of attacks of asthma.

METHODS

Outcomes were hospital admissions for asthma on 2002 days during 1987–94, for children and adults in the Trent region of England. Predictors were daily counts of 25 spore taxa from volumetric traps in Derby on the same and previous day. Admissions for asthma were adjusted for weekly, seasonal, and longer term trends by log linear autoregressive models. Spore counts on 6 days of asthma epidemics were also examined.

RESULTS

When spore counts for individual taxa were analysed as quantitative variables, two positive and two negative correlations (out of a possible 100) were significant at the 5% level. When spore counts were dichotomised at the 90th percentile, one negative and eight positive correlations (out of 100) were significant at the 5% level. All significantly positive associations related to admissions among children, but none involved the total spore count. However, total spores were above the 90th percentile on four of the six epidemic days (odds ratio (OR) 9.92, 95% confidence interval (95% CI) 1.41 to 109.84), but epidemics occurred on only four of 343 days with high total moulds.

CONCLUSIONS

There was some evidence that exceptional rates of admission for asthma tend to occur on days with high total mould spore counts, but no specific taxon was consistently implicated. The predictive power was insufficient to support a public warning system.
Mortality from multiple sclerosis and exposure to residential and occupational solar radiation: a case-control study based on death certificates
Authors: Freedman D Michal , Dosemeci Mustafa , Alavanja Michael C R
Published: July 2002

OBJECTIVES

To explore whether mortality from multiple sclerosis is negatively associated with exposure to sunlight.

METHODS

Two case-control studies based on death certificates were conducted for mortality from multiple sclerosis and non-melanoma skin cancer (as a positive control) to examine associations with residential and occupational exposure to sunlight. Cases were all deaths from multiple sclerosis between 1984 and 1995 in 24 states of the United States. Controls, which were age frequency matched to a series of cases, excluded cancer and certain neurological deaths. The effects of occupational exposure to sunlight were assessed among subjects with usual occupations requiring substantial activity, so as to exclude those whose indoor jobs resulted from disabilities subsequent to the onset of the disease. Multiple logistic regression analyses were applied, with adjustment for age, sex, race, and socioeconomic status.

RESULTS

Unlike mortality from skin cancer, mortality from multiple sclerosis was negatively associated with residential exposure to sunlight (odds ratio (OR)=0.53 (multiple sclerosis) and OR=1.24 (skin cancer)). Odds ratios for the highest occupational exposure to sunlight were 0.74 (95% confidence interval (95% CI) 0.61 to 0.89) for mortality from multiple sclerosis, compared with 1.21 (1.09 to 1.34) for mortality from non-melanoma skin cancer. The OR was 0.24 for the combined effect of the highest levels of residential and occupational exposure to sunlight on multiple sclerosis, compared with an OR of 1.38 for skin cancer.

CONCLUSIONS

In this exploratory study, mortality from multiple sclerosis, unlike mortality from skin cancer, was negatively associated with both residential and occupational exposure to sunlight.
Mortality in chemical workers potentially exposed to 2,4-dichlorophenoxyacetic acid (2,4-D) 1945–94: an update
Authors: Burns C J , Beard K K , Cartmill J B
Published: July 2002

OBJECTIVE

To update and add to a previously identified cohort of employees potentially exposed to the herbicide 2,4-dichlorophenoxyacetic acid (2,4-D). The putative association between 2,4-D and non-Hodgkin's lymphoma has been debated for more than a decade.

METHODS

Cohort members were male employees of The Dow Chemical Company who manufactured or formulated 2,4-D any time from 1945 to the end of 1994. Their mortality experience was compared with national rates and with more than 40 000 other company employees who worked at the same location.

RESULTS

330 Deaths were observed among 1517 people compared with 365 expected (standardised mortality ratio (SMR)=0.90, 95% confidence interval (95% CI) 0.81 to 1.01). There were no significantly increased SMRs for any of the causes of death analyzed. When compared with the United States rates, the SMR for non-Hodgkin's lymphoma (NHL) was 1.00 (95% CI 0.21 to 2.92). The internal comparison with other Dow employees showed a non-significant relative risk of 2.63, (95% CI 0.85 to 8.33). Death was attributed to amyotrophic lateral sclerosis (ALS) for three cohort members. Compared with the other company employees, the relative risk was 3.45 (95% CI 1.10 to 11.11). The cases were employed in the manufacture or formulation of 2,4-D at different periods (1947–9, 1950–1, and 1968–86), and for varying durations of time (1.3, 1.8, and 12.5 years).

CONCLUSION

There was no evidence of a causal association between exposure to 2,4-D and mortality due to all causes and total malignant neoplasms. No significant risk due to NHL was found. Although not an initial hypothesis, an increased relative risk of ALS was noted. This finding is unsupported by other animal and human studies.