bluuebunny/crossref_metadata_2025 huggingface dataset:
Structural Features of Nectin-2 (HveB) Required for Herpes Simplex Virus Entry
Authors: Martinez Wanda M. , Spear Patricia G.
Published: July 2002

One step in the process of herpes simplex virus (HSV) entry into cells is the binding of viral glycoprotein D (gD) to a cellular receptor. Human nectin-2 (also known as HveB and Prr2), a member of the immunoglobulin (Ig) superfamily, serves as a gD receptor for the entry of HSV-2, variant forms of HSV-1 that have amino acid substitutions at position 25 or 27 of gD (for example, HSV-1/Rid), and porcine pseudorabies virus (PRV). The gD binding region of nectin-2 is believed to be localized to the N-terminal variable-like (V) Ig domain. In order to identify specific amino acid sequences in nectin-2 that are important for HSV entry activity, chimeric molecules were constructed by exchange of sequences between human nectin-2 and its mouse homolog, mouse nectin-2, which mediates entry of PRV but not HSV-1 or HSV-2. The nectin-2 chimeric molecules were expressed in Chinese hamster ovary cells, which normally lack a gD receptor, and tested for cell surface expression and viral entry activity. As expected, chimeric molecules containing the V domain of human nectin-2 exhibited HSV entry activity. Replacement of either of two small regions in the V domain of mouse nectin-2 with amino acids from the equivalent positions in human nectin-2 (amino acids 75 to 81 or 89) transferred HSV-1/Rid entry activity to mouse nectin-2. The resulting chimeras also exhibited enhanced HSV-2 entry activity and gained the ability to mediate wild-type HSV-1 entry. Replacement of amino acid 89 of human nectin-2 with the corresponding mouse amino acid (M89F) eliminated HSV entry activity. These results identify two different amino acid sequences, predicted to lie adjacent to the C′ and C" beta-strands of the V domain, that are critical for HSV entry activity. This region is homologous to the human immunodeficiency virus binding region of CD4 and to the poliovirus binding region of CD155.
Hepatitis B Virus (HBV) Virion and Covalently Closed Circular DNA Formation in Primary Tupaia Hepatocytes and Human Hepatoma Cell Lines upon HBV Genome Transduction with Replication-Defective Adenovirus Vectors
Authors: Ren Shaotang , Nassal Michael
Published: July 2002

Hepatitis B virus (HBV), the causative agent of B-type hepatitis in humans, is a hepatotropic DNA-containing virus that replicates via reverse transcription. Because of its narrow host range, there is as yet no practical small-animal system for HBV infection. The hosts of the few related animal viruses, including woodchuck hepatitis B virus and duck hepatitis B virus, are either difficult to keep or only distantly related to humans. Some evidence suggests that tree shrews (tupaias) may be susceptible to infection with human HBV, albeit with low efficiency. Infection efficiency depends on interactions of the virus with factors on the surface and inside the host cell. To bypass restrictions during the initial entry phase, we used recombinant replication-defective adenovirus vectors, either with or without a green fluorescent protein marker gene, to deliver complete HBV genomes into primary tupaia hepatocytes. Here we show that these cells, like the human hepatoma cell lines HepG2 and Huh7, are efficiently transduced by the vectors and produce all HBV gene products required to generate the secretory antigens HBsAg and HBeAg, replication-competent nucleocapsids, and enveloped virions. We further demonstrate that covalently closed circular HBV DNA is formed. Therefore, primary tupaia hepatocytes support all steps of HBV replication following deposition of the genome in the nucleus, including the intracellular amplification cycle. These data provide a rational basis for in vivo experiments aimed at developing tupaias into a useful experimental animal system for HBV infection.
Substrate Sequence Selection by Retroviral Integrase
Authors: Zhou Haobo , Rainey G. Jonah , Wong Swee-Kee , Coffin John M.
Published: July 2002

Integration of retrovirus DNA is a specific process catalyzed by the integrase protein acting to join the viral substrate DNA (att) sequences of about 10 bases at the ends of the long terminal repeat (LTR) to various sites in the host target cell DNA. Although the interaction is sequence specific, the att sequences of different retroviruses are largely unrelated to one another and usually differ between the two ends of the viral DNA. To define substrate sequence specificity, we designed an “in vitro evolution” scheme to select an optimal substrate sequence by competitive integration in vitro from a large pool of partially randomized substrates. Integrated substrates are enriched by PCR amplification and then regenerated and subjected to subsequent cycles of selection and enrichment. Using this approach, we obtained the optimal substrate sequence of 5′-ACGACAACA-3′ for avian sarcoma-leukosis virus (ASLV) and 5′-AACA(A/C)AGCA-3′ for human immunodeficiency virus type 1, which differed from those found at both ends of the viral DNA. Clonal analysis of the integration products showed that ASLV integrase can use a wide variety of substrate sequences in vitro, although the consensus sequence was identical to the selected sequence. By a competition assay, the selected nucleotide at position 4 improved the in vitro integration efficiency over that of the wild-type sequence. Viral mutants bearing the optimal sequence replicated at wild-type levels, with the exception of some mutations disrupting the U5 RNA secondary structure important for reverse transcription, which were significantly impaired. Thus, maximizing the efficiency of integration may not be of major importance for efficient retrovirus replication.
Human GLI-2 Is a Tat Activation Response Element-Independent Tat Cofactor
Authors: Browning Catherine M. , Smith Michael J. , Clark Nina M. , Lane Brian R. , Parada Camilo , Montano Monty , KewalRamani Vineet N. , Littman Dan R. , Essex Max , Roeder Robert G. , Markovitz David M.
Published: July 2002

Zinc finger-containing GLI proteins are involved in the development of
Caenorhabditis elegans, Xenopus, Drosophila
, zebrafish, mice, and humans. In this study, we show that an isoform of human GLI-2 strongly synergizes with the Tat transactivating proteins of human immunodeficiency virus types 1 and 2 (HIV-1 and -2) and markedly stimulates viral replication. GLI-2 also synergizes with the previously described Tat cofactor cyclin T1 to stimulate Tat function. Surprisingly, GLI-2/Tat synergy is not dependent on either a typical GLI DNA binding site or an intact Tat activation response element but does require an intact TATA box. Thus, GLI-2/Tat synergy results from a mechanism of action which is novel both for a GLI protein and for a Tat cofactor. These findings link the GLI family of transcriptional and developmental regulatory proteins to Tat function and HIV replication.
Inhibition of Hepatitis B Virus Replication by the Interferon-Inducible MxA Protein
Authors: Gordien Emmanuel , Rosmorduc Olivier , Peltekian Cécile , Garreau Florianne , Bréchot Christian , Kremsdorf Dina
Published: July 2002

Human MxA is an alpha/beta interferon-inducible intracytoplasmic protein that mediates antiviral activity against several RNA viruses. We had previously shown that overexpression of the hepatitis B virus (HBV) capsid led to selective downregulation of MxA gene expression, suggesting a mechanism by which the virus escapes from the host defense system (O. Rosmorduc, H. Sirma, P. Soussan, E. Gordien, P. Lebon, M. Horisberger, C. Brechot and D. Kremsdorf, J. Gen. Virol. 80:1253–1262, 1999). In the present study, we investigated the antiviral activity of MxA protein against HBV. MxA-expressing HuH7 clones were established and transiently transfected with HBV, and viral replication was then studied. Viral protein secretion was profoundly reduced in MxA-expressing clones by 80% for HBV surface antigen (HBsAg) and 70% for HBV e antigen (HBeAg). The levels of intracytoplasmic HBsAg and HBeAg were reduced by about 80 and 50% in the two MxA-positive clones tested. A nearly complete disappearance of HBV DNA replicative intermediates was observed in MxA-expressing clones. Although the expression of total viral RNAs was not modified, two- to fourfold reductions in HBV cytoplasmic RNAs were found in MxA-expressing clones. This suggests the inhibition of HBV replication at a posttranscriptional level. Indeed, using the well-characterized posttranscriptional regulation element (PRE) reporter system, we were able to demonstrate a marked reduction (three- to eightfold) in the nucleocytoplasmic export of unspliced RNA in MxA-expressing clones. In addition, MxA protein did not interact with HBV nucleocapsid or interfere with HBV nucleocapsid formation. Our results show an antiviral effect of MxA protein on a DNA virus for the first time. MxA protein acts, at least in part, by inhibiting the nucleocytoplasmic export of viral mRNA via the PRE sequence.
Transcription Activation of Polyadenylated Nuclear RNA by Rta in Human Herpesvirus 8/Kaposi's Sarcoma-Associated Herpesvirus
Authors: Song Moon Jung , Brown Helen J. , Wu Ting-Ting , Sun Ren
Published: July 2002

Human herpesvirus 8 (HHV-8) (also known as Kaposi's sarcoma-associated herpesvirus) encodes a novel noncoding polyadenylated nuclear (PAN) RNA (also known as T1.1 or nut-1) during the early phase of lytic replication. PAN RNA is the most abundant transcript of HHV-8, comprising 80% of total poly(A)-selected transcripts in HHV-8-infected cells during lytic replication. We directly measured the abundance of PAN RNA by visualizing 1.1- to 1.2- kb PAN RNA in an ethidium bromide-stained gel from poly(A)-selected RNA. We further pursued the mechanisms by which PAN RNA expression is induced to such high levels.rta, an immediate-early gene of HHV-8, is a transactivator that is sufficient and necessary to activate lytic gene expression in latently infected cells. Ectopic expression of Rta was previously shown to induce PAN RNA expression from the endogenous viral genome and activate the PAN promoter in a reporter system. Here, we have identified the Rta-responsive element (RRE) in the PAN promoter. Deletion analysis revealed that the RRE is present in a region between nucleotides −69 and −38 of the PAN promoter. A promoter construct containing the 69 nucleotides upstream of the transcription start site of the PAN promoter was activated by Rta in the absence or presence of the HHV-8 genome. Rta activated the PAN promoter up to 7,000-fold in 293T cells and 2,000-fold in B cells. Electrophoretic mobility shift assays demonstrated that Rta formed a highly stable complex with the RRE of the PAN promoter. Our study suggests that Rta can induce PAN RNA expression by direct binding of Rta to the RRE of the PAN promoter. This study has highlighted an important mechanism controlling PAN RNA expression and also provides a model system for investigating how Rta transactivates gene expression during lytic replication.
Mutational Evidence for an Internal Fusion Peptide in Flavivirus Envelope Protein E
Authors: Allison Steven L. , Schalich Juliane , Stiasny Karin , Mandl Christian W. , Heinz Franz X.
Published: July 2002

The envelope protein E of the flavivirus tick-borne encephalitis (TBE) virus promotes cell entry by inducing fusion of the viral membrane with an intracellular membrane after uptake by endocytosis. This protein differs from other well-studied viral and cellular fusion proteins because of its distinct molecular architecture and apparent lack of involvement of coiled coils in the low-pH-induced structural transitions that lead to fusion. A highly conserved loop (the cd loop), which resides at the distal tip of each subunit and is mostly buried in the subunit interface of the native E homodimer at neutral pH, has been hypothesized to function as an internal fusion peptide at low pH, but this has not yet been shown experimentally. It was predicted by examination of the X-ray crystal structure of the TBE virus E protein (F. A. Rey et al., Nature 375:291–298, 1995) that mutations at a specific residue within this loop (Leu 107) would not cause the native structure to be disrupted. We therefore introduced amino acid substitutions at this position and, using recombinant subviral particles, investigated the effects of these changes on fusion and related properties. Replacement of Leu with hydrophilic amino acids strongly impaired (Thr) or abolished (Asp) fusion activity, whereas a Phe mutant still retained a significant degree of fusion activity. Liposome coflotation experiments showed that the fusion-negative Asp mutant did not form a stable interaction with membranes at low pH, although it was still capable of undergoing the structural rearrangements required for fusion. These data support the hypothesis that the cd loop may be directly involved in interactions with target membranes during fusion.
Persistent Infection of Human Thymic Epithelial Cells by Coxsackievirus B4
Authors: Brilot Fabienne , Chehadeh Wassim , Charlet-Renard Chantal , Martens Henri , Geenen Vincent , Hober Didier
Published: July 2002

Persistent replication of coxsackievirus B4 (CVB4) E2 (diabetogenic) and CVB4 JBV (nondiabetogenic) strains in thymic epithelial cell (TEC)-enriched cultures (≥95%) was proved by detection of positive- and negative-strand viral RNA by reverse transcription-PCR in extracted RNA from cell cultures, VP1 capsid protein detection by immunofluorescence (IF) staining, and release of infectious particles up to 30 days after infection without obvious cytolysis. By double-IF staining, cytokeratin-containing cells were shown to be susceptible to CVB4. The persistence of CVB4 was associated with a significantly increased rate of TEC proliferation (up to 70%) after 20 days of culture and a significantly increased chronic production of immunoreactive interleukin-6 (IL-6), leukemia inhibitory factor, and granulocyte-macrophage colony-stimulating factor in supernatant after 3 days of culture. The CVB4 replication and the release of cytokines were not restricted to the CVB4 E2 diabetogenic strain and did not depend on the genetic background of the host; however, TEC were more responsive to CVB4 E2 than CVB4 JBV as far as the production of cytokines.
Immunization with Surface Antigen Vaccine Alone and after Treatment with 1-(2-Fluoro-5-Methyl-β-l-Arabinofuranosyl)-Uracil (l-FMAU) Breaks Humoral and Cell-Mediated Immune Tolerance in Chronic Woodchuck Hepatitis Virus Infection
Authors: Menne Stephan , Roneker Carol A. , Korba Brent E. , Gerin John L. , Tennant Bud C. , Cote Paul J.
Published: July 2002

Woodchucks chronically infected with the woodchuck hepatitis virus (WHV) were treated with the antiviral drug 1-(2-fluoro-5-methyl-β-l-arabinofuranosyl)-uracil (l-FMAU) or placebo for 32 weeks. Half the woodchucks in each group then received four injections of surface antigen vaccine during the next 16 weeks. Vaccination alone elicited a low-level antibody response to surface antigen in most carriers but did not affect serum WHV DNA and surface antigen. Carriers treated first withl-FMAU to reduce serum WHV DNA and surface antigen and then vaccinated had a similar low-level antibody response to surface antigen. Following vaccinations, cell-mediated immunity to surface antigen was demonstrated in both groups, independent of serum viral and antigen load, but was significantly enhanced in woodchucks treated withl-FMAU and was broadened to include other viral antigens (core, e, and x antigens and selected core peptides). Cell-mediated immunity and antibody responses to surface antigen were observed after drug discontinuation in half of the carriers that receivedl-FMAU alone. Surface antigen vaccine alone or in combination with drug broke humoral and cell-mediated immune tolerance in chronic WHV infection, but the combination with drug was more effective. This suggested that a high viral and antigen load in carriers is important in maintaining immunologic tolerance during chronicity. The humoral and cellular immunity associated with the combination ofl-FMAU and vaccine resembled that observed in self-limited WHV infection. Such combination therapy represents a potentially useful approach to the control of chronic hepatitis B virus infection in humans.
Complementary Antiviral Efficacy of Hydroxyurea and Protease Inhibitors in Human Immunodeficiency Virus-Infected Dendritic Cells and Lymphocytes
Authors: Piccinini Giampiero , Foli Andrea , Comolli Giuditta , Lisziewicz Julianna , Lori Franco
Published: July 2002

Dendritic cells are susceptible to human immunodeficiency virus (HIV) infection and may transmit the virus to T cells in vivo. Scarce information is available about drug efficacy in dendritic cells because preclinical testing of antiretroviral drugs has been limited predominantly to T cells and macrophages. We compared the antiviral activities of hydroxyurea and two protease inhibitors (indinavir and ritonavir) in monocyte-derived dendritic cells and in lymphocytes. At therapeutic concentrations (50 to 100 μM), hydroxyurea inhibited supernatant virus production from monocyte-derived dendritic cells in vitro but the drug was ineffective in activated lymphocytes. Concentrations of hydroxyurea insufficient to be effective in activated lymphocytes cultured alone strongly inhibited supernatant virus production from cocultures of uninfected, activated lymphocytes with previously infected monocyte-derived dendritic cells in vitro. In contrast, protease inhibitors were up to 30-fold less efficient in dendritic cells than in activated lymphocytes. Our data support the rationale for testing of the combination of hydroxyurea and protease inhibitors, since these drugs may have complementary antiviral efficacies in different cell compartments. A new criterion for combining drugs for the treatment of HIV infection could be to include at least one drug that selectively targets HIV in viral reservoirs.
Enhancement of Hepatitis B Virus Replication by Its X Protein in Transgenic Mice
Authors: Xu Zhenming , Yen T. S. Benedict , Wu Lanying , Madden Charles R. , Tan Wenjie , Slagle Betty L. , Ou Jing-hsiung
Published: July 2002

Hepatitis B virus (HBV) X gene encodes a multifunctional protein that can regulate cellular signaling pathways, interact with cellular transcription factors, and induce hepatocellular oncogenesis. In spite of its diverse activities, the precise role of the X protein in the viral life cycle of HBV remains unclear. To investigate this question, we have produced transgenic mice that carry either the wild-type HBV genome or a mutated HBV genome incapable of expressing the 16.5-kDa X protein. Our results indicate that while the X protein is not absolutely essential for HBV replication or its maturation in transgenic mice, it can enhance viral replication, apparently by activating viral gene expression. These results demonstrate a transactivation role of the X protein in HBV replication in transgenic mice.
Functional Interaction between JC Virus Late Regulatory Agnoprotein and Cellular Y-Box Binding Transcription Factor, YB-1
Authors: Safak Mahmut , Sadowska Beata , Barrucco Robert , Khalili Kamel
Published: July 2002

Human polyomavirus JC virus (JCV) is a causative agent of progressive multifocal leukoencephalopathy which results from lytic infection of glial cells. Although significant progress has been made in understanding the regulation of JCV gene transcription, the mechanism(s) underlying the viral lytic cycle remains largely unknown. We recently reported that the JCV late auxiliary Agnoprotein may have a regulatory role in JCV gene transcription and replication. Here, we investigated its regulatory function in viral gene transcription through its physical and functional interaction with YB-1, a cellular transcription factor which contributes to JCV gene expression in glial cells. Time course studies revealed that Agnoprotein is first detected at day 3 postinfection and that its level increased during the late stage of the infection cycle. Agnoprotein is mainly localized to the cytoplasmic compartment of the infected cell, with high concentrations found in the perinuclear region. While the position of Agnoprotein throughout the infection cycle remained relatively unaltered, the subcellular distribution of YB-1 between the cytoplasm and nucleus changed. Results from coimmunoprecipitation and glutathione
S
-transferase pull-down experiments revealed that Agnoprotein physically interacts with YB-1 and that the amino-terminal region of Agnoprotein, between residues 1 and 36, is critical for this association. Further investigation of this interaction by functional assays demonstrated that Agnoprotein negatively regulates YB-1-mediated gene transcription and that the region corresponding to residues 1 to 36 of Agnoprotein is important for the observed regulatory event. Taken together, these data demonstrate that the interaction of the viral late regulatory Agnoprotein and cellular Y-box binding factor YB-1 modulates transcriptional activity of JCV promoters.
A.C. Oscillopolarographic Determination of Aluminum in Natural and Drinking Waters Using the Adsorption of the Al(III)-1,2-Dihydroxyanthraquinone-3-sulfonic Acid Complex
Authors: Bi Shuping , Zhang Zhengjiang
Published: July 2002

This paper presents a very simple and rapid method for determination of aluminum in natural and drinking waters by using a.c. oscillopolarographic adsorptive wave of the Al(III)-1,2-dihydroxyanthraquinone-3-sulfonic acid complex in a triethanolamine buffer solution of pH 7.6 at HMDE. A linear dependence between the incision height on dE/dt-E oscillogram and the aluminum concentration was obtained in the range from 5 . 10-6 to 5 . 10-5 mol l-1. The detection limit is 1 . 10-6 mol l-1 and the relative standard deviation is 6.0% for 4 . 10-5 mol l-1 aluminum. This method has the distinct advantages of cheap instrumentation, simple and rapid manipulation and deaeration is unnecessary. It is especially suitable for the fast determination of aluminum in natural and drinking water samples.
X-Ray Photoelectron Spectroscopic (XPS) Studies of Clean and Ion Beam Bombarded Sb2Te2Se and (Bi0.7Sb0.3)2Se3.0(111) Surfaces
Authors: Bastl Zdeněk , Spirovová Ilona , Janovská Michaela
Published: July 2002

The first detailed study of photoelectron spectra of Sb2Te2Se and (Bi0.7Sb0.3)2Se3 (111) clean and sputtered surfaces is presented as part of an XPS examination of the surface chemistry of these and related materials. The core level binding energies and surface chemical composition have been determined from the XPS data. On substitution of Te by Se in Sb2Te3 leading to Sb2Te2Se the core level binding energies in Sb and Te increase by 0.3 eV while in Bi2Se3 the binding energy of core electrons does not change on replacement of Bi by Sb. The measured core level shifts are caused by changes of the initial state charge distribution and result in increase of average ionicity of bonding in the Sb2Te2Se crystal. The surface composition of Sb2Te2Se sample calculated from intensities of photoelectron spectra agrees well with the bulk composition of the crystal while (Bi0.7Sb0.3)2Se3 sample shows enrichment in Bi. The effect of argon ion bombardment on surface composition for various impact conditions has been investigated. The surface enrichment in Sb and Bi for Sb2Te2Se and (Bi0.7Sb0.3)2Se3 sample due to different atomic sputtering yields is observed. It follows from the relative intensities of photoelectron spectra measured at different detection angles that the ordered arrangement of the superficial layers sampled by the XPS method is damaged by sputtering at ion energies as low as 200 eV and doses I > 2 . 1015 ion/cm2.
Preparation of Thymidine-4'-C-carboxylic Acid and Its Derivatives
Authors: Hřebabecký Hubert , Holý Antonín
Published: July 2002

3',5'-Di-O-benzoyl-4'-C-hydroxymethylthymidine (3) was prepared in four steps from 3'-O-(tert-butyldimethylsilyl)-4'-C-hydroxymethylthymidine (1). Oxidation of 3 with pyridinium dichromate afforded 3',5'-di-O-benzoylthymidine-4'-C-carboxylic acid (4) which on debenzoylation gave free thymidine-4'-C-carboxylic acid, (3R,2S,5R)-3-hydroxy-2-hydroxymethyl-5-(5-methyl-2,4-dioxo-1,2,3,4-tetrahydropyrimidin-1-yl)tetrahydrofuran-2-carboxylic acid, (5). Esterification of acid 5 with diazomethane afforded the methyl ester 6. Its isopropyl ester 7 was obtained by transesterification of the methyl ester 6. Reaction of ester 6 with ammonia and hydrazine led to the respective amide 8 and hydrazide 9. Upon reaction with 1,1'-carbonyldiimidazole, the protected acid 4 was converted into the corresponding imidazolide 11, which, without isolation, was treated with glycinamide, dimethylamine and aminoethanol to give aminocarbonylmethylamide 12a, N,N-dimethylamide 13a and hydroxyethylamide 14a, respectively. The free amides 12b, 13b and 14b were obtained by methanolysis of corresponding benzoates with methanolic sodium methoxide. Neither of the prepared compounds exhibited significant activity against HIV.
Determination of Arsenic in High-Saline Mineral Waters by Inductively Coupled Plasma Mass Spectrometry
Authors: Mestek Oto
Published: July 2002

Determination of As by ICP-MS is aggravated by the presence of Cl- ions, forming in the plasma the 40Ar35Cl+ ion from which the 75As+ ion cannot be discriminated. The presence of 1 000 mg l-1 Cl- gives rise to a signal corresponding approximately to 3 μg l-1 As. Interferences can be reduced by about 70% by the addition of 4 vol.% methanol, the remaining fraction has to be corrected mathematically. A treatment based on the measured intensities of the 40Ar37Cl+ or 35Cl16O+ ions can result in overcorrection; the signal of the 35Cl+ ion was found more suitable for the purpose. The 35Cl+/40Ar35Cl+ signal ratio is constant in the concentration range of 400-1 000 mg l-1 Cl- at least. The detection limit (3σ) found by measuring solutions which contained various amounts of Cl- ions was 0.03 μg l-1 As. This two-step correction for interferences was applied to the analysis of a mineral water with a chloride concentration of 1 400 mg l-1. The results obtained by the calibration graph method and by the standard addition method were in a good agreement (1.50 μg l-1 vs 1.44 μg l-1 As, respectively), whereas a high overestimation (4.2 μg l-1 As) resulted if the correction was omitted. Relative standard deviation of the determination was 3.2%.
Antineoplastic Agents 385. The Isolation and Structure of a Scalarane-Type Sesterterpene from the Indian Ocean Porifera Hyrtios erecta
Authors: Pettit George R. , Cichacz Zbigniew A. , Tan Rui , Herald Delbert L. , Melody Noeleen , Hoard Michael S. , Doubek Dennis L. , Hooper John N. A.
Published: July 2002

Bioassay-guided separation techniques were employed to isolate (3.3·10-7% yield) a new murine P388 lymphocytic leukemia cell line inhibitor (ED50 2.9 μg/ml) 12-O-deacetyl-19-deoxyscalarin from extracts of the Republic of Maldives marine sponge Hyrtios erecta. The structure was deduced using high field 2D NMR and high resolution mass spectral methods and confirmed by X-ray crystal structure determination.
Oxidative Dehydrogenation of Ethane on Vanadium-Containing Aluminophosphates with AFI Structure
Authors: Blasco Teresa , Concepción Patricia , López Nieto José M. , Martínez-Arias Arturo
Published: July 2002

MeAPO-5 (Me = V, Mg, Co, Mn) and VMeAPO-5 (Me = Mg, Co, Mn) with AFI structure were prepared by hydrothermal synthesis and characterized by nitrogen-adsorption, TPR, diffuse reflectance (UV-VIS) and ESR spectroscopies. Their catalytic performance in the oxidative dehydrogenation of ethane using molecular oxygen was also studied. Although different catalytic behaviour was observed depending on the metal incorporated, Vanadia-metal containing materials were the most selective catalysts. The importance of both redox and acid character of the catalysts on their catalytic properties is discussed.
Competitive Extraction of Some Bases by Carbollylcobaltate Anion from Water Into Chloroform
Authors: Navrátil Oldřich , Skaličan Zdeněk , Kobliha Zbyněk , Halámek Emil
Published: July 2002

The bis[undecahydro-7,8-dicarbaundecaborato(2-)]cobaltate(1-) (X-) has been used for complementary study of its ionic associates with some cations of organic bases and quaternary salts. For the optimization of present analytical methods, quinuclidin-3-yl hydroxy(diphenyl)acetate, 1-(1-phenylcyclohexyl)piperidine, dibenzo[b,f][1,4]oxazepine and cocaine, were studied by competitive extraction method. X- labelled with 60Co was used as carrier anion, triphenylmethane and azo dyes as competitive anions. The aqueous phase was 0.1 and 0.01 M HCl, the organic phase was chloroform. A comparison was made with earlier results obtained by extraction spectrophotometry.
Changes in the epidemiological pattern of sudden infant death syndrome in southeast Norway, 1984–1998: implications for future prevention and research
Authors: Arnestad M , Andersen M , Vege Å , Rognum T O
Published: July 2002

AIM

To look for changes in risk factors for sudden infant death syndrome (SIDS) after decrease and stabilisation of the SIDS rate.

METHODS

Questionnaires were distributed to parents of 174 SIDS infants, dying between 1984 and 1998, and 375 age and sex matched controls in southeast Norway.

RESULTS

The proportion of infants sleeping prone has decreased, along with the decrease in SIDS rate for the region during the periods studied, but over half of the SIDS victims are still found in the prone position. As the number of SIDS cases has decreased, additional risk factors have become more significant. Thus, after 1993, a significantly increased risk of SIDS is seen when the mother smokes during pregnancy. After 1993, young maternal age carries an increased risk. Maternal smoking and young maternal age are associated with each other. For SIDS victims, an increase in the number of infants found dead while co-sleeping is seen, and the age peak between 2 and 4 months and the winter peak have become less pronounced.

CONCLUSION

Changes in risk factor profile following the decrease in SIDS rate in the early 1990s, as well as consistency of other factors, provides further clues to SIDS prevention and to the direction of further studies of death mechanisms.
Aerobic responses of prepubertal boys to two modes of training
Authors: Williams Craig A , Armstrong Neil , Powell Julian
Published: July 2002

Objective—To investigate the effects of two contrasting eight week training programmes on the aerobic performance of 39 prepubescent boys (mean age 10.1 years).

Methods—All boys were volunteer subjects from three city schools and the schools were matched by a health related behaviour questionnaire. All of the boys were assessed as Tanner stage one for genitalia and pubic hair development. Criterion laboratory tests included peak V̇o2as assessed by an incremental discontinuous treadmill test to voluntary exhaustion. Submaximal measurements of heart rate, minute ventilation (V̇e) and V̇o2were also recorded during the treadmill test. One of the schools provided the control group (n = 14), and boys from the other schools followed two contrasting training programmes. The first was a sprint interval running programme (n = 12) comprising 10 second and 30 second sprints, and the second a continuous cycle ergometer programme (n = 13) maintaining a heart rate in the range 80–85% of maximum for 20 minutes on a Monark cycle ergometer. After eight weeks training three times a week, the three groups were retested.

Results—There were no significant differences in peak V̇o2(p>0.05) with training in either of the groups. Neither were there significant changes in any of the submaximal variables V̇o2, V̇e, or heart rate (p>0.05).

Conclusion—The findings of this study indicate that neither eight week sprint interval running nor continuous cycle ergometer training programmes significantly improve maximal or submaximal indicators of the aerobic performance of prepubertal boys.
A trial of recombinant human granulocyte colony stimulating factor for the treatment of very low birthweight infants with presumed sepsis and neutropenia
Authors: Russell A R Bedford , Emmerson A J B , Wilkinson N , Chant T , Sweet D G , Halliday H L , Holland B , Davies E G
Published: July 2002

OBJECTIVES

The primary objective was to investigate the safety of recombinant human granulocyte colony stimulating factor (rhG-CSF) for the treatment of very low birthweight infants (VLBW) with sepsis and relative neutropenia, specifically with regard to worsening of respiratory distress and thrombocytopenia and all cause mortality. Secondary objectives were to evaluate duration of ventilation, intensive care, and antibiotic use as markers of efficacy.

DESIGN

Neonates (⩽  28 days) in intensive care, with birth weights of 500–1500 g, absolute neutrophil count (ANC) of ⩽ 5 × 109/l, and clinical evidence of sepsis, were randomly assigned to receive either rhG-CSF (10 μg/kg/day) administered intravenously (n = 13), or placebo (n = 15) for a maximum of 14 days, in addition to standard treatment and antibiotics. All adverse events, oxygenation index, incidence of thrombocytopenia, all cause mortality, duration of ventilation, intensive care and antibiotic treatment, and ANC recovery were compared between the two groups.

RESULTS

Adverse events and oxygenation index were not increased by, and thrombocytopenia was not attributable to, treatment with rhG-CSF. At 6 and 12 months postmenstrual age, there were significantly fewer deaths in the group receiving rhG-CSF (1/13v7/15; p ⩽ 0.038). There was a non-significant trend towards a reduction in duration of ventilation, intensive care, and antibiotic use in the rhG-CSF group. There was a significantly more rapid increase in ANC in the rhG-CSF treated babies (p < 0.001).

CONCLUSIONS

In a small randomised placebo controlled trial in a highly selected group of neonates, adjuvant treatment with rhG-CSF increased ANC rapidly, and no treatment related adverse events were identified. Mortality at 6 and 12 months postmenstrual age was significantly lower in the treatment group. A large trial investigating efficacy in a similar group of neonates is warranted.

Key messages

rhG-CSF increases the absolute neutrophil count in very low birthweight infants with neutropenia and sepsis

Thrombocytopenia is not an effect of rhG-CSF treatment

Potential beneficial effects on long term survival require further investigation
Skin tags and the atherogenic lipid profile
Authors: Crook M A
Published: July 2002

This report details four patients who had skin tags, mainly on their torso, neck, and axillae, and who also displayed an abnormal lipid profile. All showed an increased serum triglyceride (fasting > 1.70 mmol/litre) and a decreased high density lipoprotein (HDL) cholesterol (< 1.1 mmol/litre in women and 1.0 mmol/litre for men) concentration. The displayed lipid profile is also known as the atherogenic profile and is associated with insulin resistance, type 2 diabetes mellitus, and an increased risk of cardiovascular disease. Two of the patients had impaired glucose tolerance and one had type 2 diabetes mellitus. Three of the individuals had coronary artery disease. Skin tags might be a useful clinical sign that could alert clinicians to screen such individuals for abnormal lipids, type 2 diabetes mellitus, and cardiovascular disease.
Respiratory diseases in children and outdoor air pollution in São Paulo, Brazil: a time series analysis
Authors: Gouveia Nelson , Fletcher Tony
Published: July 2002

OBJECTIVES

To investigate the short term effects of air pollution on the respiratory morbidity of children living in São Paulo, Brazil, one of the largest cities in the developing world.

METHODS

Daily counts of hospital admissions due to respiratory diseases along with daily levels of meteorological variables and air pollutants (PM10, SO2, NO2, O3, and CO) were analysed with Poisson regression. Final models were adjusted for the effects of time trends, seasonal patterns, weekdays, holidays, meteorological factors, and serial correlation.

RESULTS

Daily admissions of children to hospital for total respiratory disease and pneumonia showed significant increases associated with O3(5–8%), NO2(9%), and with PM10(9%) (results are for an increase from the 10th to the 90th percentile of pollution measurements). Consistently, effects for pneumonia were greater than for all respiratory diseases combined. Also, effects on infants (children <1 year old) presented higher estimates. Similar associations were found for asthma admissions. Point estimates for most pollutants were higher for asthma than for other diagnosed admissions. However, these associations were not significant.

CONCLUSIONS

These results agree with the limited publications on this subject but indicate a rather smaller magnitude of effects. Nevertheless, given the present concentrations of air pollution in São Paulo and the large population potentially exposed attention should be directed to minimise such effects.
Crystalline silica exposure and lung cancer mortality in diatomaceous earth industry workers: a quantitative risk assessment
Authors: Rice F L , Park R , Stayner L , Smith R , Gilbert S , Checkoway H
Published: July 2002

OBJECTIVE

To use various exposure-response models to estimate the risk of mortality from lung cancer due to occupational exposure to respirable crystalline silica dust.

METHODS

Data from a cohort mortality study of 2342 white male California diatomaceous earth mining and processing workers exposed to crystalline silica dust (mainly cristobalite) were reanalyzed with Poisson regression and Cox's proportional hazards models. Internal and external adjustments were used to control for potential confounding from the effects of time since first observation, calendar time, age, and Hispanic ethnicity. Cubic smoothing spline models were used to assess the fit of the models. Exposures were lagged by 10 years. Evaluations of the fit of the models were performed by comparing their deviances. Lifetime risks of lung cancer were estimated up to age 85 with an actuarial approach that accounted for competing causes of death.

RESULTS

Exposure to respirable crystalline silica dust was a significant predictor (p<0.05) in nearly all of the models evaluated and the linear relative rate model with a 10 year exposure lag seemed to give the best fit in the Poisson regression analysis. For those who died of lung cancer the linear relative rate model predicted rate ratios for mortality from lung cancer of about 1.6 for the mean cumulative exposure to respirable silica compared with no exposure. The excess lifetime risk (to age 85) of mortality from lung cancer for white men exposed for 45 years and with a 10 year lag period at the current Occupational Safety and Health Administration (OSHA) standard of about 0.05 mg/m3for respirable cristobalite dust is 19/1000 (95% confidence interval (95% CI) 5/1000 to 46/1000).

CONCLUSIONS

There was a significant risk of mortality from lung cancer that increased with cumulative exposure to respirable crystalline silica dust. The predicted number of deaths from lung cancer suggests that current occupational health standards may not be adequately protecting workers from the risk of lung cancer.
Mortality from cardiovascular diseases and exposure to inorganic mercury
Authors: Boffetta P , Sällsten G , Garcia-Gómez M , Pompe-Kirn V , Zaridze D , Bulbulyan M , Caballero J-D , Ceccarelli F , Kobal A B , Merler E
Published: July 2002

OBJECTIVE

To study the mortality from cardiovascular and other chronic non-neoplastic diseases after long term exposure to inorganic mercury. Limited information is available on the effect of chronic exposure to mercury on the cardiovascular system.

METHODS

The mortality was studied among 6784 male and 265 female workers from four mercury mines and mills in Spain, Slovenia, Italy, and the Ukraine. Workers were employed between 1900 and 1990; the follow up period lasted from the 1950s to the 1990s. The mortality of the workers was compared with national reference rates.

RESULTS

Among men, there was a slight increase in overall mortality (standardised mortality ratio (SMR) 1.08, 95% confidence interval (95% CI) 1.04 to 1.12). An increased mortality was found from hypertension (SMR 1.46, 95% CI 1.08 to 1.93), heart diseases other than ischaemic (SMR 1.36, 95% CI 1.20 to 1.53), pneumoconiosis (SMR 27.1, 95% CI 23.1 to 31.6), and nephritis and nephrosis (SMR 1.55, 95% CI 1.13 to 2.06). The increase in mortality from cardiovascular diseases was not consistent among countries. Mortality from hypertension and other heart diseases increased with estimated cumulative exposure to mercury; mortality from ischaemic heart disease and cerebrovascular diseases increased with duration of employment, but not with estimated exposure to mercury. Results among women were hampered by few deaths.

CONCLUSION

Despite limited quantitative data on exposure, possible confounding, and likely misclassification of disease, the study suggests a possible association between employment in mercury mining and refining and risk in some groups of cardiovascular diseases.
Unexplained groin pain: safety and reliability of herniography for the diagnosis of occult hernias
Authors: Gwanmesia I I , Walsh S , Bury R , Bowyer K , Walker S
Published: July 2002

A retrospective study of our initial experience of herniography in a district general hospital is presented. A total of 43 herniograms were performed in 41 patients (median age 57, range 16–77, 27 males, 14 females) over a two year period. Four herniograms were unsuccessful due to failed intraperitoneal contrast injection, of which two were repeated (success rate 90.5%). A total of 25 groin hernias were identified radiologically (two on the asymptomatic side). Twenty one patients underwent surgery and a hernia was confirmed in 19 (true positive rate 90.5%). Sixteen herniograms were considered negative and after a median follow up of 28 months (range 16–42 months), none of these patients have developed a hernia. There were no major complications. It is concluded that herniography is a safe and reliable method of determining or excluding the presence of an occult groin hernia.
Prevalence of microalbuminuria in type 2 diabetes mellitus at a diabetes centre in southern India
Authors: Varghese A , Deepa R , Rema M , Mohan V
Published: July 2002

OBJECTIVE

The aim of this study was to determine the prevalence and risk factors for microalbuminuria among south Indian type 2 diabetic patients attending a diabetes centre.

METHODS

One thousand four hundred and twenty five type 2 diabetic patients attending a diabetes centre in south India were recruited for the study. Urinary albumin concentration was measured by immunoturbodimetric assay. Microalbuminuria was diagnosed if the urinary albumin excretion was >30 mg/g of creatinine.

RESULTS

Overall prevalence of microalbuminuria was 36.3% (95% confidence interval 33.8 to 38.9). The prevalence of microalbuminuria increased with the increase in duration of diabetes. Multivariate regression analysis revealed age, diastolic blood pressure, glycated haemoglobin, fasting plasma glucose, and duration of diabetes to be associated with microalbuminuria.

CONCLUSION

The overall prevalence of microalbuminuria in this south Indian clinic population and its risk factors are similar to that reported in Europeans.
Abstention from smoking extends life and compresses morbidity: a population based study of health expectancy among smokers and never smokers in Denmark
Authors: Brønnum-Hansen Henrik , Juel Knud
Published: July 2002

OBJECTIVE

To estimate health expectancy— that is, the average lifetime in good health—among never smokers, ex-smokers, and smokers in Denmark.

DESIGN

A method suggested by Peto and colleagues in 1992 for estimating smoking attributable mortality rates was used to construct a life table for never smokers. This life table and relative risks for death for ex-smokers and smokers versus never smokers were used to estimate life tables for ex-smokers and smokers. Life tables and prevalence rates of health status were combined and health expectancy was calculated by Sullivan's method.

SETTING

The Danish adult population.

MAIN OUTCOME MEASURES

The expected lifetime in self rated good health or without longstanding illness for never smokers and smokers.

RESULTS

The expected lifetime of a 20 year old man who will never begin to smoke is 56.7 years, 48.7 (95% confidence interval (CI), 46.8 to 50.7) years of which are expected to be in self rated good health. The corresponding figures for a man who smokes heavily are 49.5 years, 36.5 (95% CI 35.0 to 38.1 ) years of which are in self rated good health. A 20 year old woman who will never begin to smoke can expect to live a further 60.9 years, with 46.4 (95% CI 44.9 to 47.8) years in self rated good health; if she is a lifelong heavy smoker, her expected lifetime is reduced to 53.8 years, 33.8 (95% CI 31.7 to 35.9) years of which are in self rated good health. Health expectancy based on long standing illness is reduced for smokers when compared with never smokers.

CONCLUSIONS

Smoking reduces the expected lifetime in good health and increases the expected lifetime in poor health.
Hungary introduces a total ban on tobacco advertising
Authors: Szilágyi T
Published: July 2002

Hungary has introduced a total ban on direct and indirect advertising for tobacco products
Ascovirgaria occulta gen. et sp.nov., Jumillera hawaiiensis sp.nov., and Lopadostoma hawaiianum sp.nov. from Hawaii
Authors: Rogers Jack D , Ju Yu-Ming
Published: July 2002

Ascovirgaria occulta gen. et sp.nov., a xylariaceous pyrenomycete with perithecia embedded in decayed wood beneath a blackened surface, is described. Its anamorph is Virgaria nigra (Link) Nees, a cosmopolitan dematiaceous hyphomycete long suspected to have xylariaceous affinities. Jumillera hawaiiensis sp.nov. and its Libertella state, and Lopadostoma hawaiianum sp.nov. and its dry scolecosporous anamorph, are described.Key words: Ascomycetes, Pyrenomycetes, Xylariaceae.
Isolation of A/D and C genome specific dispersed and clustered repetitive DNA sequences fromAvena sativa
Authors: Ananiev Evgueni V , Vales M Isabel , Phillips Ronald L , Rines Howard W
Published: July 2002

DNA gel-blot and in situ hybridization with genome-specific repeated sequences have proven to be valuable tools in analyzing genome structure and relationships in species with complex allopolyploid genomes such as hexaploid oat (Avena sativa L., 2n = 6x = 42; AACCDD genome). In this report, we describe a systematic approach for isolating genome-, chromosome-, and region-specific repeated and low-copy DNA sequences from oat that can presumably be applied to any complex genome species. Genome-specific DNA sequences were first identified in a random set of A. sativa genomic DNA cosmid clones by gel-blot hybridization using labeled genomic DNA from different Avena species. Because no repetitive sequences were identified that could distinguish between the A and D gneomes, sequences specific to these two genomes are refereed to as A/D genome specific. A/D or C genome specific DNA subfragments were used as screening probes to identify additional genome-specific cosmid clones in the A. sativa genomic library. We identified clustered and dispersed repetitive DNA elements for the A/D and C genomes that could be used as cytogenetic markers for discrimination of the various oat chromosomes. Some analyzed cosmids appeared to be composed entirely of genome-specific elements, whereas others represented regions with genome- and non-specific repeated sequences with interspersed low-copy DNA sequences. Thus, genome-specific hybridization analysis of restriction digests of random and selected A. sativa cosmids also provides insight into the sequence organization of the oat genome.Key words: oat, cosmid library, in situ hybridization.