bluuebunny/crossref_metadata_2025 huggingface dataset:
High-Magnitude, Virus-Specific CD4 T-Cell Response in the Central Nervous System of Coronavirus-Infected Mice
Authors: Haring Jodie S. , Pewe Lecia L. , Perlman Stanley
Published: July 2002

The neurotropic JHM strain of mouse hepatitis virus (MHV) causes acute encephalitis and chronic demyelinating encephalomyelitis in rodents. Previous results indicated that CD8 T cells infiltrating the central nervous system (CNS) were largely antigen specific in both diseases. Herein we show that by 7 days postinoculation, nearly 30% of the CD4 T cells in the acutely infected CNS were MHV specific by using intracellular gamma interferon (IFN-γ) staining assays. In mice with chronic demyelination, 10 to 15% of the CD4 T cells secreted IFN-γ in response to MHV-specific peptides. Thus, these results show that infection of the CNS is characterized by a large influx of CD4 T cells specific for MHV and that these cells remain functional, as measured by cytokine secretion, in mice with chronic demyelination.
Herpes Simplex Virus-Induced Keratitis: Evaluation of the Role of Molecular Mimicry in Lesion Pathogenesis
Authors: Deshpande Shilpa P. , Lee Sujin , Zheng Mei , Song Byeongwoon , Knipe David , Kapp Judith A. , Rouse Barry T.
Published: July 2002

Viruses are suspected but usually unproven triggering factors in autoimmunity. One favored mechanism to explain the role of viruses in the genesis of autoimmunity is molecular mimicry. An immunoinflammatory blinding lesion called herpetic stromal keratitis (HSK) that follows ocular infection with herpes simplex virus (HSV) is suggested to result from a CD4+T-cell response to a UL6 peptide of HSV that cross-reacts with a corneal autopeptide shared with the immunoglobulin G2ab(IgG2ab) isotype. The present report reevaluates the molecular mimicry hypothesis to explain HSK pathogenesis. Our results failed to reveal cross-reactivity between the UL6 and IgG2abpeptides or between peptide reactive T cells and HSV antigens. More importantly, animals infected with HSV failed to develop responses that reacted with either peptide, and infection with a recombinant vaccinia UL6 vector failed to cause HSK, in spite of generating UL6 reactivity. Other lines of evidence also failed to support the molecular mimicry hypothesis, such as the failure to affect HSK severity upon tolerization of susceptible BALB/c and B-cell-deficient mice with IgG2abor UL6 peptides. An additional study system revealed that HSK could be induced in mouse strains, such as the OT2 × RAG1−/−mice (T cell receptor transgenic recognizing OVA323–339) that were unable to produce CD4+T-cell responses to any detectable HSV antigens. Our results cast doubt on the molecular mimicry hypothesis as an explanation for the pathogenesis of HSK and indicate that if autoimmunity is involved its likely proceeds via a bystander activation mechanism.
Individual Contributions of Mutant Protease and Reverse Transcriptase to Viral Infectivity, Replication, and Protein Maturation of Antiretroviral Drug-Resistant Human Immunodeficiency Virus Type 1
Authors: Bleiber Gabriela , Munoz Miguel , Ciuffi Angela , Meylan Pascal , Telenti Amalio
Published: July 2002

Human immunodeficiency virus type 1 (HIV-1) variants resistant to protease (PR) and reverse transcriptase (RT) inhibitors may display impaired infectivity and replication capacity. The individual contributions of mutated HIV-1 PR and RT to infectivity, replication, RT activity, and protein maturation (herein referred to as “fitness”) in recombinant viruses were investigated by separately cloning PR, RT, and PR-RT cassettes from drug-resistant mutant viral isolates into the wild-type NL4-3 background. Both mutant PR and RT contributed to measurable deficits in fitness of viral constructs. In peripheral blood mononuclear cells, replication rates (means ± standard deviations) of RT recombinants were 72.5% ± 27.3% and replication rates of PR recombinants were 60.5% ± 33.6% of the rates of NL4-3. PR mutant deficits were enhanced in CEM T cells, with relative replication rates of PR recombinants decreasing to 15.8% ± 23.5% of NL4-3 replication rates. Cloning of the cognate RT improved fitness of some PR mutant clones. For a multidrug-resistant virus transmitted through sexual contact, RT constructs displayed a marked infectivity and replication deficit and diminished packaging of Pol proteins (RT content in virions diminished by 56.3% ± 10.7%, and integrase content diminished by 23.3% ± 18.4%), a novel mechanism for a decreased-fitness phenotype. Despite the identified impairment of recombinant clones, fitness of two of the three drug-resistant isolates was comparable to that of wild-type, susceptible viruses, suggestive of extensive compensation by genomic regions away from PR and RT. Only limited reversion of mutated positions to wild-type amino acids was observed for the native isolates over 100 viral replication cycles in the absence of drug selective pressure. These data underscore the complex relationship between PR and RT adaptive changes and viral evolution in antiretroviral drug-resistant HIV-1.
Cervicovaginal Lamina Propria Lymphocytes: Phenotypic Characterization and Their Importance in Cytotoxic T-Lymphocyte Responses to Simian Immunodeficiency Virus SIVmac251
Authors: Stevceva Liljana , Kelsall Brian , Nacsa Janos , Moniuszko Marcin , Hel Zdeněk , Tryniszewska Elzbieta , Franchini Genoveffa
Published: July 2002

Most human immunodeficiency virus (HIV) type 1 infections occur by the mucosal route. Thus, it is important to assess the immune responses to HIV in the vaginal, cervical, and rectal compartments. Here we quantitated the virus-specific CD8+T-cell response and characterized the phenotype of lymphocytes in the genital tracts of naive macaques, macaques acutely or chronically infected with simian immunodeficiency virus SIVmac251, and macaques chronically infected with chimeric simian/human immunodeficiency virus SHIVKU2.Vaginal biopsy samples or samples obtained at the time of euthanasia were used in this analysis. The percentage of Gag-specific, tetramer-positive T cells was as high as 13 to 14% of the CD3+CD8+T-cell population in the vaginal and cervical laminae propriae of both SIVmac251and SHIVKU2chronically infected macaques. In most cases, the frequency of this response in the cervicovaginal compartment far exceeded the frequency in the blood or the draining iliac lymph node. Vaginal laminae propriae of naive macaques contained 55 to 65% CD3+CD8+cells and 28 to 34% CD3+CD4+cells, while the majority of intraepithelial cells were CD8+T cells (75 to 85%). For the same cells, the surface expression of CD62L was low whereas that of αEβ7 was high. No difference in the expression of CD45RA on CD8+T cells was observed in the chronic stage of SIVmac251infection. Although no decrease in the percentage of CD4+cells in the genital tract was observed within the first 12 days of infection, by 6 weeks from SIVmac251infection and thereafter the percentage of CD4+T cells was decreased in the laminae propriae of the vagina and cervix. Expression of CD45RA did not differ in naive and acutely SIVmac251infected macaques. Information on the quality and quantity of local immune responses may help in the design of vaccine strategies aimed at containing viral replication at the site of viral encounter.
Transduction of Interphase Cells by Avian Sarcoma Virus
Authors: Katz Richard A. , Greger James G. , Darby Kristen , Boimel Pamela , Rall Glenn F. , Skalka Anna Marie
Published: July 2002

It has been generally believed that oncoretroviruses are dependent on mitosis for efficient nuclear entry of viral DNA. We previously identified a nuclear localization signal in the integrase protein of an oncoretrovirus, avian sarcoma virus (ASV), suggesting an active import mechanism for the integrase-DNA complex (G. Kukolj, R. A. Katz, and A. M. Skalka, Gene 223:157-163, 1998). Here, we have evaluated the requirement for mitosis in nuclear import and integration of ASV DNA. Using a modified ASV encoding a murine leukemia virus amphotropic
env
gene and a green fluorescent protein (GFP) reporter gene, DNA nuclear import was measured in cell cycle-arrested avian (DF-1) as well as human (HeLa) and mouse cells. The results showed efficient accumulation of nuclear forms of ASV DNA in γ-irradiation-arrested cells. Efficient transduction of a GFP reporter gene was also observed after infection of cells that were arrested with γ-irradiation, mitomycin C, nocodazole, or aphidicolin, confirming that nuclear import and integration of ASV DNA can occur in the absence of mitosis. By monitoring GFP expression in individual cells, we also obtained evidence for nuclear import of viral DNA during interphase in cycling cells. Lastly, we observed that ASV can transduce postmitotic mouse neurons. These results support an active nuclear import mechanism for the oncoretrovirus ASV and suggest that this mechanism can operate in both nondividing and dividing cells.
Pre- and Postexposure Prophylaxis of Ebola Virus Infection in an Animal Model by Passive Transfer of a Neutralizing Human Antibody
Authors: Parren Paul W. H. I. , Geisbert Tom W. , Maruyama Toshiaki , Jahrling Peter B. , Burton Dennis R.
Published: July 2002

A neutralizing human monoclonal antibody, KZ52, protects guinea pigs from lethal Ebola Zaire virus challenge. Administration before or up to 1 h after challenge resulted in dose-dependent protection by the antibody. Interestingly, some antibody-treated animals survived despite developing high-level viremia, suggesting that the mechanism of protection by KZ52 may extend beyond reduction of viremia by virus neutralization. KZ52 is a promising candidate for immunoprophylaxis of Ebola virus infection.
Identification of Immunodominant Neutralizing Epitopes on the Hemagglutinin Protein of Rinderpest Virus
Authors: Sugiyama Makoto , Ito Naoto , Minamoto Nobuyuki , Tanaka Seiichi
Published: July 2002

The immunodominant epitopes on the hemagglutinin protein of rinderpest virus (RPV-H) were determined by analyzing selected monoclonal antibody (MAb)-resistant mutants and estimating the level of antibody against each epitope in five RPV-infected rabbits with the competitive enzyme-linked immunosorbent assay (c-ELISA). Six neutralizing epitopes were identified, at residues 474 (epitope A), 243 (B), 548 to 551 (D), 587 to 592 (E), 310 to 313 (G), and 383 to 387 (H), from the data on the amino acid substitutions of hemagglutinin protein of MAb-resistant mutants and the reactivities of MAbs against RPV-H to the other morbilliviruses. The epitopes identified in this study are all positioned on the loop of the propeller-like structure in a hypothetical three-dimensional model of RPV-H (J. P. M. Langedijk et al., J. Virol. 71:6155-6167, 1997). Polyclonal sera obtained from five rabbits infected experimentally with RPV were examined by c-ELISA using a biotinylated MAb against each epitope as a competitor. Although these rabbit sera hardly blocked binding of each MAb to epitopes A and B, they moderately blocked binding of each MAb to epitopes G and D and strongly blocked binding of each MAb to epitopes E and H. These results suggest that epitopes at residues 383 to 387 and 587 to 592 may be immunodominant in humoral immunity to RPV infection.
Decreased Frequency of the
HLA-DRB1*11
Allele in Patients with Chronic Hepatitis C Virus Infection
Authors: Yenigün Ayla , Durupinar Belma
Published: July 2002

A genetically determined resistance or susceptibility to chronic hepatitis C virus (HCV) infection may make an important contribution to the course of liver disease and may be linked to the human major histocompatibility complex (MHC). The aim of this study was to investigate the HLA class II genotype profile in chronic hepatitis C and to determine the HLA-hepatitis C association. The experimental population was composed of 49 unrelated chronic HCV patients (31 females, 18 males; mean age, 54.4 ± 1.7 years; range, 34 to 73 years). The control population consisted of 43 ethnically matched healthy donors.
HLA-DR
and -DQ alleles were studied for patients and controls by a PCR-sequence-specific-primer low-resolution method. Anti-HCV was investigated with enzyme-linked immunosorbent assay II, and HCV RNA was investigated with reverse transcriptase nested PCR. The HLA class II allele,
DRB1*11
, was found at reduced frequency in 49 patients with chronic hepatitis C (anti-HCV and HCV RNA positive) compared to that for controls (22.4 versus 51.0%;
P
< 0.01, odds ratio = 0.3, confidence interval = 0.1 to 0.7). No further HLA associations with chronic HCV infection were observed, and there was no correlation between the stage of disease and HLA.
DRB1*11
was also found at reduced frequency in all HCV antibody-positive patients compared to controls (corrected
P
= not significant).
DRB1*11
was associated with chronic HCV infection, and it is possible that
HLA-DRB1*11
may have a protective feature in chronic HCV infection. In addition,
DRB1*11
was associated with protection from HCV infection. These findings suggest that host HLA class II genotype is an important factor determining the outcome of infection with HCV.
Interferon-Regulated Pathways That Control Hepatitis B Virus Replication in Transgenic Mice
Authors: Guidotti Luca G. , Morris Amber , Mendez Heike , Koch Rick , Silverman Robert H. , Williams Bryan R. G. , Chisari Francis V.
Published: July 2002

We previously showed that the intrahepatic induction of cytokines such as alpha/beta interferon (IFN-α/β) and gamma interferon (IFN-γ) inhibits hepatitis B virus (HBV) replication noncytopathically in the livers of transgenic mice. The intracellular pathway(s) responsible for this effect is still poorly understood. To identify interferon (IFN)-inducible intracellular genes that could play a role in our system, we crossed HBV transgenic mice with mice deficient in IFN regulatory factor 1 (IRF-1), the double-stranded RNA-activated protein kinase (PKR), or RNase L (RNase L) (IRF-1−/−, PKR−/−, or RNase L−/−mice, respectively), three well-characterized IFN-inducible genes that mediate antiviral activity. We showed that unmanipulated IRF-1−/−or PKR−/−transgenic mice replicate HBV in the liver at slightly higher levels than the respective controls, suggesting that both IRF-1 and PKR individually appear to mediate signals that modulate HBV replication under basal conditions. These same animals were responsive to the antiviral effects of the IFN-α/β inducer poly(I-C) or recombinant murine IFN-γ, suggesting that under these conditions, either the IRF-1 or the PKR genes can mediate the antiviral activity of the IFNs or other IFN-inducible genes mediate the antiviral effects. Finally, RNase L−/−transgenic mice were undistinguishable from controls under basal conditions and after poly(I-C) or IFN-γ administration, suggesting that RNase L does not modulate HBV replication in this model.
Mouse Model for the Equilibration Interaction between the Host Immune System and Human T-Cell Leukemia Virus Type 1 Gene Expression
Authors: Furuta Rika A. , Sugiura Kikuya , Kawakita Shigenari , Inada Takefumi , Ikehara Susumu , Matsuda Tadashi , Fujisawa Jun-ichi
Published: July 2002

To study the involvement of immune responses against Tax of human T-cell leukemia virus type 1 (HTLV-1) in the growth of and gene suppression in Tax-expressing tumor cells in vivo, we established a model system involving C57BL/6J mice and a syngeneic lymphoma cell line, EL4. When mice were immunized by DNA-based immunization with Tax expression plasmids, solid tumor formation upon subcutaneous inoculation of EL4 cells expressing green fluorescent protein-fused Tax (Gax) under the control of the HTLV-1 enhancer was strongly inhibited, and in vitro analysis showed that DNA immunization elicited cytotoxic T-lymphocyte (CTL) responses but not production of antibodies to Tax protein. Since EL4/Gax cells inoculated into DNA-immunized mice were not completely eradicated but were maintained as small solid tumors for a long period, there appeared to be a certain equilibrium between CTL activity and the growth of Gax-expressing cells. With such a balance, expression of the Gax gene in EL4/Gax cells was strongly suppressed. These results suggested that gene expression under the control of the HTLV-1 long terminal repeat and Tax is silenced in vivo, resulting in an equilibrium between viral expression and the host immune system. Such a balance would represent a status of persistent infection by HTLV-1 in virus-infected individuals during the latency period.
Physical Association of the K3 Protein of Gamma-2 Herpesvirus 68 with Major Histocompatibility Complex Class I Molecules with Impaired Peptide and β2-Microglobulin Assembly
Authors: Yu Y. Y. Lawrence , Harris Michael R. , Lybarger Lonnie , Kimpler Lisa A. , Myers Nancy B. , Virgin IV Herbert W. , Hansen Ted H.
Published: July 2002

To persist in the presence of an active immune system, viruses encode proteins that decrease expression of major histocompatibility complex class I molecules by using a variety of mechanisms. For example, murine gamma-2 herpesvirus 68 expresses the K3 protein, which causes the rapid turnover of nascent class I molecules. In this report we show that certain mouse class I alleles are more susceptible than others to K3-mediated down regulation. Prior to their rapid degradation, class I molecules in K3-expressing cells exhibit impaired assembly with β2-microglobulin. Furthermore, K3 is detected predominantly in association with class I molecules lacking assembly with high-affinity peptides, including class I molecules associated with the peptide loading complex TAP/tapasin/calreticulin. The detection of K3 with class I assembly intermediates raises the possibility that molecular chaperones involved in class I assembly are involved in K3-mediated class I regulation.
Infectious and Whole Inactivated Simian Immunodeficiency Viruses Interact Similarly with Primate Dendritic Cells (DCs): Differential Intracellular Fate of Virions in Mature and Immature DCs
Authors: Frank I. , Piatak M. , Stoessel H. , Romani N. , Bonnyay D. , Lifson J.D. , Pope M.
Published: July 2002

As potential targets for human immunodeficiency virus type 1 and simian immunodeficiency virus (HIV-1 and SIV), dendritic cells (DCs) likely play a significant role in the onset and spread of infection as well as in the induction of antiviral immunity. Using the SIV-macaque system to study the very early events in DC-virus interactions, we compared chemically inactivated SIV having conformationally and functionally intact envelope glycoproteins (2,2′-dithiodipyridine [AT-2] SIV) to infectious and heat-treated SIV. Both human and macaque DCs interact similarly with SIV without detectable effects on DC viability, phenotype, or endocytic function. As assessed by measuring cell-associated viral RNA, considerable amounts of virus are captured by the DCs and this is reduced when the virus is heat treated or derived from a strain that expresses low levels of envelope glycoprotein. Immunostaining for SIV proteins and electron microscopy indicated that few intact virus particles are retained at the periphery of the endocytically active, immature DCs. This contrasts with a perinuclear localization of numerous virions in large vesicular compartments deeper within mature DCs (in which macropinocytosis is down-regulated). Both immature and mature DCs are capable of clathrin-coated pit-mediated uptake of SIV, supporting the notion that the receptor-mediated uptake of virus can occur readily in mature DCs. While large numbers of whole viruses were preferentially found in mature DCs, both immature and mature DCs contained similar amounts of viral RNA, suggesting that different uptake/virus entry mechanisms are active in immature and mature DCs. These findings have significant implications for cell-to-cell transmission of HIV-1 and SIV and support the use of AT-2 SIV, an authentic but noninfectious form of virus, as a useful tool for studies of processing and presentation of AT-2 SIV antigens by DCs.
Lack of both Fas Ligand and Perforin Protects from Flavivirus-Mediated Encephalitis in Mice
Authors: Licon Luna Rosa M. , Lee Eva , Müllbacher Arno , Blanden Robert V. , Langman Rod , Lobigs Mario
Published: July 2002

The mechanism by which encephalitic flaviviruses enter the brain to inflict a life-threatening encephalomyelitis in a small percentage of infected individuals is obscure. We investigated this issue in a mouse model for flavivirus encephalitis in which the virus was administered to 6-week-old animals by the intravenous route, analogous to the portal of entry in natural infections, using a virus dose in the range experienced following the bite of an infectious mosquito. In this model, infection with 0.1 to 105PFU of virus gave mortality in ∼50% of animals despite low or undetectable virus growth in extraneural tissues. We show that the cytolytic effector functions play a crucial role in invasion of the encephalitic flavivirus into the brain. Mice deficient in either the granule exocytosis- or Fas-mediated pathway of cytotoxicity showed delayed and reduced mortality. Mice deficient in both cytotoxic effector functions were resistant to a low-dose peripheral infection with the neurotropic virus.
Adenovirus Binding to the Coxsackievirus and Adenovirus Receptor or Integrins Is Not Required To Elicit Brain Inflammation but Is Necessary To Transduce Specific Neural Cell Types
Authors: Thomas Clare E. , Edwards Penny , Wickham Thomas J. , Castro Maria G. , Lowenstein Pedro R.
Published: July 2002

Intracranial administration of adenovirus vectors elicits rapid, capsid-mediated dose-dependent brain inflammation. The mechanisms through which adenovirus capsids trigger inflammation in the brain remain unknown. We determined whether adenovirus interaction with the primary and secondary cell surface receptors for infection (CAR and αv integrins) was necessary to trigger acute adenovirus-mediated brain inflammation, and, furthermore, whether capsid mutations that abrogated CAR and integrin binding altered vector tropism in the brain. Vectors ablated for CAR binding, but retaining integrin binding function, transduced equivalent areas of brain compared to vectors with wild-type capsids; however, vector tropsim was dramatically altered. Vectors with wild-type capsids predominantly transduced oligodendrocytes, whereas mutation of the fiber protein to ablate CAR binding resulted in a loss of oligodendrocyte transduction and a consequent redirection of transduction to neurons and other types of glial cells. Combined mutations of fiber and penton base that ablate both CAR and integrin binding almost abolished brain transduction. Thus, doubly-ablated capsids engineered to express new ligands should allow complete vector retargeting in the central nervous system. Although transduction by the doubly-ablated vectors was reduced by greater than 95%, inflammation was not reduced compared to wild-type vectors, demonstrating that brain inflammation occurs independently of adenovirus binding and infection of cells via CAR and integrin receptors.
Electron Pairing and Chemical Bonds
Authors: Ponec Robert
Published: July 2002

The recently proposed population analysis of pair densities is applied to the investigation of molecular structure of several simple molecules. The values of pairon populations straightforwardly reproduce the classical structural formula including the multiplicity of the bonds and provide thus the so far missing link between quantum chemical and Lewis's classical picture of bonding. As demonstrated, the formalism of the proposed approach provides strong theoretical evidence for the frequently expected but so far elusive role of electron pairing in chemical bonding.
Preparation of Dimethyl Carbonate from Methanol and Carbon Dioxide in the Presence of Organotin Compounds
Authors: Kizlink Juraj , Pastucha Ivan
Published: July 2002

Dibutyltin dialkoxides react with methanol and carbon dioxide to give dimethyl carbonate in 60 to 220 mole % yields with respect to the organotin compound. The higher yields of the carbonate (150 up to 330 mole %) have been achieved with the use of chemical scavengers of the reaction water.
Preparation of β-D-Glucopyranosyl Derivatives of 1,6:2,3- and 1,6:3,4-Dianhydro-β-D-hexopyranoses and Their 1H and 13C NMR Spectra
Authors: Buděšínský Miloš , Černý Miloslav , Černý Ivan , Sámek Stanislav , Trnka Tomáš
Published: July 2002

The corresponding acetylated and free 2-O- and 4-O-glucosyl derivatives of dianhydrohexoses Ib - VIIb and Ic - VIIc have been obtained by the reactions of 2,3,4,6-tetra-O-acetyl-α-D-glucopyranosyl bromide (IX) with 1,6:3,4- and 1,6:2,3-dianhydro-β-D-hexopyranoses (Ia - VIIa). Structure of the products and the effects of glycosylation upon chemical shifts and conformations of the disaccharides prepared have been studied using 1H and 13C NMR spectra.
Electrochemical Degradation of Polychlorinated Biphenyls
Authors: Janderka Pavel , Brož Pavel
Published: July 2002

The feasibility of electrochemical conversion of polychlorinated biphenyls to the parent hydrocarbon in N,N-dimethylformamide was studied with respect to the charge and mass efficiency of the process. The process was conducted in two variants, viz. as indirect conversion through pre-electrolysis of an alkali salt solution, and as direct electroreducing splitting of the carbon-chlorine bonds. Mercury served as the working electrode; the suitability of other metals as cathode materials was also examined by slow cyclic voltammetry.
Hydrogen Evolution from Aqueous Solutions on Indium Phosphide Photocathodes
Authors: Jakubec Ivo , Bludská Jana , Pekárek Ladislav , Vondrák Jiří , Mareš Jiří
Published: July 2002

Hydrogen evolution from aqueous solutions on the p-indium phosphide photocathodes was studied. The efficiency of this process is affected by the crystallographic orientation of the photocathode surface. The influence of platinum metal additives in the electrolyte on water photolysis is discussed.
Polarographic and Voltammetric Determination of 4,4'-Bis[(4-diethanolamino-6-(2,5-disulfophenylamino)-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonic Acid
Authors: Barek Jiří , Hrnčíř Roman , Moreira Josino C. , Zima Jiří
Published: July 2002

The polarographic and voltammetric behaviour was studied for 4,4'-bis[(4-diethanolamino-6-(2,5-disulfophenylamino)-1,3,5-triazin-2-yl)amino]stilbene-2,2'-disulfonic acid, which is the basis of many commercial optical whitening agents. The optimum conditions were found for quantitation of this substance in tetraethylammonium bromide solutions in dimethylformamide containing 5% (v/v) water using TAST polarography, differential pulse polarography, linear sweep voltammetry at a hanging mercury drop electrode, and differential pulse voltammetry at a hanging mercury drop electrode over the concentration regions of 100-500, 10-500, 10-500, and 1-100 mmol l-1, respectively. The practical applicability of the new analytical methods to the determination of the substance in technical products was verified.
Cytochrome P-450 from Tulip Bulbs (Tulipa fosteriana L.) Oxidizes an Azo Dye Sudan I (1-Phenylazo-2-hydroxynaphthalene, Solvent Yellow 14) in vitro
Authors: Stiborová Marie , Hansíková Hana
Published: July 2002

The microsomal fraction from tulip bulbs (Tulipa fosteriana L.) contains cytochrome P-450 enzymes catalyzing the NADPH-dependent oxidation of the xenobiotic substrate, an azo dye Sudan I (1-phenylazo-2-hydroxynaphthalene, Solvent Yellow 14). C-Hydroxy derivatives [1-(4-hydroxyphenylazo)-2-hydroxynaphthalene, 1-phenylazo-2,6-dihydroxynaphthalene, 1-(4-hydroxyphenylazo)-2,6-dihydroxynaphthalene] and the benzenediazonium ion are the products of the Sudan I oxidation. The oxidation of Sudan I has also been assessed in a reconstituted electron-transport chain with the isolated cytochrome P-450, isolated plant NADPH-cytochrome P-450 reductase and phospholipid. The results are discussed from the point of view of the role of cytochromes P-450 in the metabolism of xenobiotics in plants.
Decay Characteristics of Electrostatically Collected Samples of Radon Daughters
Authors: Jech Čestmír , Janout Zdeněk , Koníček Ján , Kubašta Jiří , Pospíšil Stanislav , Vobecký Miloslav
Published: July 2002

Samples of radon daughters collected electrostatically from the air in various conditions were analyzed by measuring their decay curves (both integral and for the spectrometrically resolved components). The results are helpful for establishing electrostatic collection as a sampling method in radon daughters measurements.
Silicon-29 NMR Spectra of Trimethylsilylated Alcohols
Authors: Kvíčalová Magdalena , Čermák Jan , Blechta Vratislav , Schraml Jan
Published: July 2002

29Si NMR spectra of trimethylsilyl (TMS) derivatives of 26 simple alcohols were measured under standardized conditions (i.e., in sufficiently diluted deuteriochloroform solutions). Due to association with the solvent the chemical shifts are in almost all cases larger than those reported earlier for different solutions. This observation is in agreement with the proposed mechanism of steric effects as being due to sterically controlled association with the solvent. The use of chloroform as a solvent enhances steric effects but at the same time it can reduce small differences due to polar effects in closely related compounds. In the studied class of compounds the gross dependence of the chemical shift on polar effects is not substantially affected by the change of the solvent.
Determination of the Accurate Values of the Rate Constant and Thermodynamic Parameters for the Rotation About the C(sp2)-C(aryl) Bond; Adamantan-1-yl 3-Bromo-2,4,6-trimethylphenyl Ketone
Authors: Přibylová Eva , Holík Miroslav
Published: July 2002

Four programs for the 1H NMR line shape analysis: two commercial - Winkubo (Bruker) and DNMR5 (QCPE 165) and two written in our laboratory - Newton (in Microsoft Excel) and Simtex (in Matlab) have been tested in order to get highly accurate rate constants of the hindered rotation about a single bond. For this purpose four testing criteria were used, two of them were also developed by us. As supplementary determinations the rate constants obtained for the coalescence temperature and for the thermal racemization of chromatographically separated enantiomers were used which fitted well the temperature dependence of the rate constants determined by the line shape analysis. As a test compound adamantan-1-yl 3-bromo-2,4,6-trimethylphenyl ketone was prepared and studied. It was shown that supermodified simplex method used in our algorithm (Simtex), though time consuming, gives the most accurate values of the rate constants and consequently the calculated thermodynamic parameters Ea, ∆H≠, and ∆S≠ lay in relatively narrow confidence intervals.
Singlet-Triplet Splitting in Methylene: An Accurate Description of Dynamic and Nondynamic Correlation by Reduced Multireference Coupled Cluster Method
Authors: Li Xiangzhu , Paldus Josef
Published: July 2002

A classical multireference problem - the singlet-triplet separation in methylene - is examined by the recently introduced reduced multireference (RMR) singles and doubles coupled cluster (CCSD) method, using both double zeta plus polarization (DZP) and large atomic natural orbital (ANO) basis sets. In the former case, the performance of the RMR CCSD as well as of other approaches is assessed by a comparison with the full configuration interaction (FCI) result that represents the exact solution for this basis, while in the latter case a comparison is made with the experiment. It is shown that using a minimal two-configuration reference space, the RMR CCSD result compares well with either FCI or experiment; and is of the same quality as that provided by the two-reference state universal MR CCSD theory. Both MR CCSD approaches give a balanced description for the singlet and triplet states involved and correct the shortcomings of the single reference CCSD approach that is lacking in the presence of nondynamical correlation effects.
Epalons: Synthesis of 3α,7α-Dihydroxy-5α-pregnan-20-one
Authors: Chodounská Hana , Kasal Alexander
Published: July 2002

3α,7α-Dihydroxy-5α-pregnan-20-one (12) was prepared from (20R)-pregn-5-ene-3β,20-diyl 3-acetate 20-benzoate (1). ∆5-Olefin was oxidized in an allylic position and hydrogenated. Inversion of a configuration at carbon C-3 was carried out by solvolysis in N,N-dimethylformamide of 3β-tosylate in the presence of sodium nitrite. For stereoselective reduction of the 7-oxo group, L-Selectride® was used.
Linear Heptapeptides Containing DNA-Intercalators. Synthesis and Interaction with DNA
Authors: Matušina Zbyněk , Olbřímková Radomíra , Votavová Hana , Neumann Josef , Hradilek Martin , Souček Milan , Maloň Petr , Kodíček Milan , Stibor Ivan
Published: July 2002

Five peptides of general structure X-Ser-Pro-Thr-Ser-Pro-Ser-Y (X = Tyr, quinoxaline- 2-carbonyl, acridine-9-carbonyl, Y = Tyr, (quinoxalin-2-yl)amino) were prepared using standard solid-phase peptide synthesis technique. Their interaction with DNA (calf thymus DNA and plasmids pUC9, p∆NS and pGEMEX) was studied using UV and CD spectroscopy, sedimentation analysis and agarose gel electrophoresis after treatment with topoisomerase I. In contrast to earlier findings (Suzuki M.: Nature 1990, 344, 562) intercalation into DNA structure has not been proved for any compound studied.
Synthesis of Rhodium Complexes with Novel Perfluoroalkyl Substituted Cyclopentadienyl Ligands
Authors: Čermák Jan , Auerová Kateřina , Nguyen Huong Thi Thu , Blechta Vratislav , Vojtíšek Pavel , Kvíčala Jaroslav
Published: July 2002

Mixtures of isomers of (perfluoroalkyl)tetramethylcyclopenta-1,3-dienes (CH3)4C5H(CF2)nCF3 (n = 3, 5, 7, 9) were synthesized as precursors of new cyclopentadienyl ligands for organotransition metal catalysis in fluorous biphase media and characterized by combination of GC-MS and 13C NMR spectroscopy. Rhodium(III) chloro complexes [Rh{(CH3)4C5(CF2)nCF3}Cl2]2 and rhodium(I) carbonyl complexes [Rh{(CH3)4C5(CF2)nCF3}(CO)2] were prepared from the cyclopentadienes and molecular structure of [Rh{(CH3)4C5(CF2)5CF3}Cl2]2 was determined by X-ray diffraction. The ligands are electronically close to the unsubstituted cyclopentadienyl as shown by values of carbonyl stretching frequencies in the carbonyl complexes. Neither carbonyl frequencies nor NMR chemical shifts of the complexes are substantially affected by the length of the perfluoroalkyl chain.
Study of Energies and Geometries of Dibenzo[a,h]pyrene, Its Epoxides and Related Compounds
Authors: Rioseras-Garcia Maria-Jesús J. , Hernando-Huelmo Jose-Maria
Published: July 2002

A conformational study of energies and geometries of stable compounds obtained from dibenzo[a,h]pyrene by enzymatic treatment with oxygen was carried out using the semiempirical AM1 quantum mechanical method. The energies of possible isomers are strongly dependent on the position occupied by the oxygen atom in the epoxides obtained from dibenzo[a,h]pyrene.
Relation of anterior pelvic tilt during running to clinical and kinematic measures of hip extension
Authors: Schache Anthony G , Blanch Peter D , Murphy Anna T
Published: July 2002

Background—Limited hip extension flexibility due to tight hip flexor musculature or anterior hip capsular and ligamentous structures is a possible cause of increased anterior tilt of the pelvis during running. However, to date, research exploring this relation, as well as the kinematic relation between anterior tilt of the pelvis and peak hip extension range of motion during running, is not available.

Objective—To assess the relation of anterior pelvic tilt during running to peak hip extension range of motion measured during running and hip extension flexibility measured clinically.

Methods—Hip extension flexibility was assessed using the Thomas test, and the three dimensional kinematic motion of the pelvis and hips were recorded using a VICON motion analysis system with 14 elite athletes running on a treadmill at 20 km/h.

Results—Anterior pelvic tilt displayed a significant (p<0.01) correlation with peak hip extension range of motion during running. Anterior pelvic tilt tended to be increased in runners who displayed reduced absolute peak hip extension range of motion during terminal stance. No significant correlation was shown for hip extension flexibility with either anterior pelvic tilt or peak hip extension range of motion during running.

Conclusions—The outcomes of this study indicate that anterior pelvic tilt and hip extension are coordinated movements during running. Static hip extension flexibility measured using the modified Thomas test does not appear to be reflective of these dynamic movements.
Frozen chips: an unusual cause of severe frostbite injury: Figure 1
Authors: Graham Colin A , Stevenson James
Published: July 2002

A case of severe frostbite injury to the right foot is presented. This was caused by the inappropriate application of a bag of frozen chips to the foot in an attempt to ease non-specific pain. No specific acute traumatic injury was identified. As the patient was a teacher of physical education, the pain had initially been assumed to originate from a minor musculoskeletal injury. Full recovery ensued after surgical excision of necrotic tissue and split skin grafting. The danger of inappropriate overenthusiastic use of ice packs or other frozen material to treat soft tissue injuries is emphasised. The need for education to prevent similar future injuries is discussed.
Physical activity and all cause mortality in women: a review of the evidence
Authors: Oguma Y , Sesso H D , Paffenbarger R S , Lee I-M
Published: July 2002

A computer assisted literature search was performed (Medline, 1966–2000) to examine the association of physical activity with all cause mortality in women. It was concluded that, by adhering to current guidelines for physical activity and expending about 4200 kJ of energy a week, women can postpone mortality. The magnitude of benefit experienced by women is similar to that seen in men.
Effect of ethylene vinyl acetate (EVA) closed cell foam on transmitted forces in mouthguard material
Authors: Westerman B , Stringfellow P M , Eccleston J A , Harbrow D J
Published: July 2002

Objectives:To compare transmitted forces through ethylene vinyl acetate (EVA) mouthguard material and the same EVA material with gas inclusions in the form of a closed cell foam.

Method:EVA mouthguard materials with and without foam gas inclusions and 4 mm thick were impacted with a constant force from an impact pendulum. Various porosity levels in the foam materials were produced by 1%, 5%, and 10% by weight foaming agent. The forces transmitted through the EVA after energy absorption by the test materials were measured with a force sensor and compared.

Results:Only minor non-significant differences in transmitted forces through the EVA with and without foam were shown.

Conclusions:The inclusion of gas in the form of a closed cell foam in 4 mm thick EVA mouthguard materials did not improve the impact performance of the EVA mouthguard material.
Splenic B cell lymphoma with lymphocyte clusters in peripheral blood smears
Authors: Shelton Jack. B , Frank Indra N
Published: July 2002

EDTA induced clumping of lymphoid cells, both benign and malignant, in peripheral blood samples has been reported only rarely. Such clustering presents the laboratory and pathologist with unique difficulties in the accurate diagnosis of these disorders. A case of low grade B cell splenic lymphoma is presented with lymphocyte clumping in smears made from EDTA anticoagulated peripheral blood, the fourth case described in which neoplastic lymphoid cells form clusters in vitro in peripheral blood. The association with splenic lymphomas (three of the four cases) is intriguing but its significance remains uncertain.
The man who claimed to be a paedophile
Authors: Hill Simon A
Published: July 2002

A psychiatrist recounts a case of a man presenting with severe depression who claimed to have abused children and his pet dog.

Clinical management of the case hinged on whether this claim was true, a lie or delusional. The uncertainty over this raised complex ethical dilemmas regarding confidentiality and protection of the public (and animals).
The morality of coercion
Authors: Glick Shimon M
Published: July 2002

The author congratulates Dr Brian Hurwitz, who recently reported the successful “intimidation” of an elderly competent widow into accepting badly needed therapy for a huge ulcerated carcinoma. He reports approvingly of the Israeli Patients' Rights Law, enacted in 1996, which demands detailed informed consent from competent patients before permitting treatment. But the law also provides an escape clause which permits coercing a competent patient into accepting life-saving therapy if an ethics committee feels that if treatment is imposed the patient will give his/her consent retroactively. He suggests this approach as an appropriate middle road between overbearing paternalism and untrammelled autonomy.
A little toleration, please
Authors: McKnight Christopher
Published: July 2002

Value pluralism does not imply relativism or subjectivism about values. What it does is allow respect for an at least limited toleration of values with which one may profoundly disagree. Thus a doctor can respect the autonomy of a patient whose values he does not share.
Randomised clinical trials: a source of ethical dilemmas
Authors: Verdú-Pascual Fernando , Castelló-Ponce Ana
Published: July 2002

Advances in medicine are closely linked to clinical research, but certain study procedures may be in conflict with the fundamental principles of ethics and codes of conduct in medicine. Following an analysis of two studies involving treatments for acute myocardial infarction (AMI), the admissibility of continuing a study was questioned after the initial results for two types of treatment showed that one was significantly better than the other. Also considered doubtful was the information provided to patients with the object of obtaining their informed consent.
Why sex selection should be legal
Authors: McCarthy David
Published: July 2002

Reliable medically assisted sex selection which does not involve abortion or infanticide has recently become available, and has been used for non-medical reasons. This raises questions about the morality of sex selection for non-medical reasons. But reasonable people continue to disagree about the answers to these questions. So another set of questions is about what the law should be on medically assisted sex selection for non-medical reasons in the face of reasonable disagreement about the morality of sex selection. This paper sketches a way of thinking about what the law should be, and concludes, contrary to what the law is in many places, that medically assisted sex selection for non-medical reasons ought to be legal.
Prevention of disability on grounds of suffering
Authors: Edwards S D
Published: July 2002

This paper examines one particular justification for the screening and termination of embryos/fetuses which possess genetic features known to cause disability. The particular case is that put forward in several places by John Harris. He argues that the obligation to prevent needless suffering justifies the prevention of the births of disabled neonates. The paper begins by rehearsing Harris's case. Then, drawing upon claims advanced in a recent paper in the Journal of Medical Ethics, it is subjected to critical scrutiny, focusing on Harris's “suffering claim” (the claim that a life with disability inevitably involves suffering on a significant scale).1It is argued that the suffering claim must be false if understood as an empirical claim. And, even if understood as a conceptual truth, it mistakenly assimilates the concepts of harm and suffering. Finally, again focusing on Harris's recent work in this area, his characterisation of disability as a “harmed condition” is shown not to apply in the case of at least some moderate forms of intellectual disability.
Clinical governance—watchword or buzzword?
Authors: Campbell Alastair V
Published: July 2002

In the latest reform of the National Health Service great emphasis has been placed on the achievement and maintenance of quality. Mechanisms for ensuring this are being set up under the general title of “clinical governance”. What is the meaning of this term? The metaphor behind the phrase is of navigation through stormy seas, but who guides the helmsman? Clinical ethics committees could have a part to play in these changes, provided their role is properly understood. Clinical governance is concerned with management according to an agreed set of aims. The task of ethics committees is Socratic rather than managerial. They should ask fundamental questions about the ethical norms of the services provided and give critical appraisal of the moral character of institutional policies. If these tasks are carried out then governance may become a watchword rather than just another buzzword.
Operation Lifeline Sudan
Authors: Taylor-Robinson S D
Published: July 2002

The provision of aid in war zones can be fraught with political difficulties and may itself foster inequalities, as it is rare to be allowed access to civilians on both sides of a conflict. Over the past decade, a United Nations (UN) brokered agreement has allowed Operation Lifeline Sudan (OLS), a UN “umbrella” organisation, to provide the diplomatic cover and operational support to allow long term humanitarian and emergency food aid to both the government and the rebel sides in the long-running south Sudanese civil war. Over the years, the destruction of infrastructure in the country has meant that the provision of basic health care has been seriously hampered. Operation Lifeline Sudan has coordinated the work of most of the non-governmental organisations (NGOs), working in this part of Africa. Each NGO has had responsibility for a particular area of the country and has worked closely with the local Sudanese authorities on either side of the conflict, conforming to strict codes of conduct or “ground rules”, based on neutrality. Operation Lifeline Sudan has provided an air-bridge for emergency relief supplies in regions where road access is impossible, either because of landmines, or simply because the roads do not exist. The war continues, however, and the underlying causes of war—economic exploitation, marginalisation of communities, lack of political representation, and systematic violence and abuse remain unsolved. The warring factions have brought some OLS operations in south Sudan to a standstill recently, for certain political reasons that could have compromised the neutrality of the OLS-coordinated humanitarian aid schemes. It would appear that the only resolution to the country's problems are external political pressure to get the respective combatants to negotiate and, less probably, an undertaking by countries of the developed world not to continue to supply arms. Nevertheless, OLS may serve as a model for how medical aid can be delivered in an even-handed way to the populations of countries where there is civil war, irrespective of where they may live.
Actions, causes, and psychiatry: a reply to Szasz: Table 1
Authors: Brassington I M
Published: July 2002

In a recent paper, it was argued forcefully by Thomas Szasz that it is crucial to the scientific credibility of psychiatry that it abandon talk of the behaviour of the mentally “ill” in terms of causes: such behaviour is notcausedby their condition—it simply hasreasons, which are discounted by the medical model. It is argued in this paper that Szasz's theory is incomplete for two reasons: first, in assuming that reasons are radically different from causes, it cannot account for the possibility that “sane” behaviour might be just as much caused as “insane”; and second, it tacitly assumes that the origin of behaviour always lies with the agent—a view that arguably is an accident of grammar. Hence while there is no mental illness, this is because there is nothing thatcould beill—and this means that there is no such thing as mental “health” either.