bluuebunny/crossref_metadata_2025 huggingface dataset:
Type I interferon structures: Possible scaffolds for the interferon-alpha receptor complex
Authors: Nagabhushan Tattanahalli L , Reichert Paul , Walter Mark R , Murgolo Nicholas J
Published: October 2002

The structures of several type I interferons (IFNs) are known. We review the structural information known for IFN alphas and compare them to other interferons and cytokines. We also review the structural information known or proposed for IFNcell receptor complexes. However, the structure of the IFN  cell receptor  IFN receptor2 (IFNAR2) and IFN receptor1 (IFNAR1) complex has not yet been determined. This paper describes a structural model of human IFN-IFNAR2/IFNAR1 complex using human IFN-α2bdimer as the ligand. Both the structures of recombinant human IFN-α2band IFN-β were determined by X-ray crystallography as zinc-mediated dimers. Our proposed model was generated using human IFN-α2bdimer docked with IFNAR2/IFNAR1. We compare our model with the receptor complex models proposed for IFN-β and IFN-γ to contrast similarities and differences. The mutual binding sites of human IFN-α2band IFNAR2/IFNAR1 complex are consistent with available mutagenesis studies.Key words: three dimensional structure, antiviral activity, receptor, interferon.
Browse occurrence, biomass, and use by white-tailed deer in a northern New Brunswick deer yard
Authors: Morrison Shawn F , Forbes Graham J , Young Steven J
Published: October 2002

Winter browse abundance influences population growth of white-tailed deer (Odocoileus virginianus) in northeastern North America, where they regularly experience harsh winter conditions. We surveyed browse biomass and abundance among vegetation types and determined the extent of browse species selection and avoidance in a northeastern deer yard. Deer browsed 19 species but only red and striped maples (Acer rubrum L. and Acer pensylvanicum L.) were consistently selected. Regenerating, mature mixedwood, and mature sprucefir stands were most likely to have high amounts of browse cover. Mature mixedwood stands had greater total browse biomass than submature hardwood and mature cedar stands. It is possible that our observed selection and avoidance of browse species reflects changes in availability as snow depth increased in middle to late winter. Thus, browse availability and use should be interpreted with respect to known patterns of deer habitat use during varying degrees of winter severity. We recommend that mixedwood stands be recognized as important part of winter habitat for deer. We underscore their importance for wintering deer, because they allow them to access shelter and browse simultaneously.
COMPUTER SIMULATIONS OF HEAVY-ION ELASTIC SCATTERING
Authors: CHA MOON HOE , KIM YONG JOO
Published: October 2002

We have used the computer language Java to develop a computer simulation program for heavy-ion elastic scattering based on the parameterized phase shift model. Using this program, we have carried out a χ2-fit to the observed differential cross-section data of the heavy-ion elastic scattering and performed computer simulations of the angular distribution, the deflection function, the reaction cross-section, the scattering matrix element, and the analysis results as graphical representations. The program is also applied to elastic scattering of the 12C+12C system at E lab = 1016 MeV.
PENROSE LIMIT OF AdS4 × N0,1,0 AND ${\mathcal N} = 3$ GAUGE THEORY
Authors: AHN CHANGHYUN
Published: October 2002

We consider M-theory on AdS4 × N0,1,0 where N0,1,0 = ( SU (3) × (2))/( SU (2) × U (1)). We review a Penrose limit of AdS4 × N0,1,0 that provides the pp-wave geometry of AdS4 × S7. There exists a subsector of three-dimensional [Formula: see text] dual gauge theory, by taking both the conformal dimension and R-charge large with the finiteness of their difference, which has enhanced [Formula: see text] maximal supersymmetry. We identify operators in the [Formula: see text] gauge theory with supergravity KK excitations in the pp-wave geometry and describe how the [Formula: see text] gauge theory operators originating from both [Formula: see text] short vector multiplet and [Formula: see text] long gravitino multiplet fall into [Formula: see text] supermultiplets.
IRON EFFECT ON DIELECTRIC PROPERTIES OF CALCIUM-SILICA-PHOSPHATE GLASSES
Authors: SIMON V.
Published: October 2002

Dielectric constant εr and loss tan δ of x Fe 2 O 3 · 45(3.34 CaO · P 2 O 5)(55 - x) SiO 2 samples were investigated as a function of composition (0 ≤ x ≤ 30 mol %), temperature and frequency. The samples are characterized by relatively high dielectric constants, which denote bonding defects in the glass network. At all temperatures and frequencies investigated, the dielectric loss for the P 2 O 5- CaO-SiO 2 matrix is lower than that for iron-containing samples. The dielectric constant is higher for the glass matrix than for the iron-containing samples only in the first part of the temperature range. Where the dielectric constant of the glass matrix is higher than the corresponding value for the iron-containing samples the temperature range, exponentially narrows with the decrease of frequency. The dielectric loss in the iron-containing samples is mainly attributed to iron ions conduction.
Ixolaris, a novel recombinant tissue factor pathway inhibitor (TFPI) from the salivary gland of the tick, Ixodes scapularis: identification of factor X and factor Xa as scaffolds for the inhibition of factor VIIa/tissue factor complex
Authors: Francischetti Ivo M. B. , Valenzuela Jesus G. , Andersen John F. , Mather Thomas N. , Ribeiro José M. C.
Published: October 2002

Saliva of the hard tick and Lyme disease vector, Ixodes scapularis, has a repertoire of compounds that counteract host defenses. Following sequencing of an I scapularis salivary gland complementary DNA (cDNA) library, a clone with sequence homology to tissue factor pathway inhibitor (TFPI) was identified. This cDNA codes for a mature protein, herein called Ixolaris, with 140 amino acids containing 10 cysteines and 2 Kunitz-like domains. Recombinant Ixolaris was expressed in insect cells and shown to inhibit factor VIIa (FVIIa)/tissue factor (TF)–induced factor X (FX) activation with an inhibitory concentration of 50% (IC50) in the picomolar range. In nondenaturing gel, Ixolaris interacted stoichiometrically with FX and FXa but not FVIIa. Ixolaris behaves as a fast-and-tight ligand of the exosites of FXa and γ-carboxyglutamic acid domainless FXa (des-Gla-FXa), increasing its amidolytic activity. At high concentration, Ixolaris attenuates the amidolytic activity of FVIIa/TF; however, in the presence of DEGR-FX or DEGR-FXa (but not des-Gla-DEGR-FXa), Ixolaris becomes a tight inhibitor of FVIIa/TF as assessed by recombinant factor IX (BeneFIX) activation assays. This indicates that FX and FXa are scaffolds for Ixolaris in the inhibition of FVIIa/TF and implies that the Gla domain is necessary for FVIIa/TF/Ixolaris/FX(a) complex formation. Additionally, we show that Ixolaris blocks FXa generation by endothelial cells expressing TF. Ixolaris may be a useful tool to study the structural features of FVIIa, FX, and FXa, and an alternative anticoagulant in cardiovascular diseases.
Mutations associated with hemophilia A in the 558-565 loop of the factor VIIIa A2 subunit alter the catalytic activity of the factor Xase complex
Authors: Jenkins P. Vincent , Freas Jan , Schmidt Kyla M. , Zhou Qian , Fay Philip J.
Published: October 2002

The 558-565 loop region in the A2 subunit of factor (F) VIIIa forms a direct interface with FIXa. We have expressed and purified B-domainless FVIII (FVIIIWT) and B-domainless FVIII containing the hemophilia A–associated mutations Ser558Phe, Val559Ala, Asp560Ala, Gln565Arg, and the activated protein C cleavage site mutant Arg562Ala. Titration of FVIIIa in FXa generation assays showed that the mutant and wild-type proteins had similar functional affinities for FIXa (dissociation constant [Kd] values ∼5 nM-20 nM and ∼100 nM-250 nM in the presence and absence of phospholipid, respectively). The catalytic activities of the factor Xase complex composed of the hemophilia A–associated FVIII species were markedly reduced both in the presence and absence of phospholipid. FVIIIWT and FVIIIArg562Ala showed catalytic rate constant (kcat) values of approximately 60 minute−1 in the presence of phospholipid, whereas the hemophilia A–associated mutants showedkcat values ranging from 3.3 minute−1 to 7.5 minute−1. In the absence of phospholipid, all kcat values were reduced but FVIIIWT and FVIIIArg562Ala retained higher activities as compared with the hemophilic mutant FVIII forms. Fluorescence anisotropy experiments using fluorescein-modified FIXa confirmed that all FVIII forms interacted with FIXa. However, the presence of factor X yielded minimal increases in anisotropy observed with the mutant factor VIII forms, consistent with their reduced activity. These results show that residues within the 558-565 loop are critical in modulating FIXa enzymatic activity but do not contribute significantly to the affinity of FVIIIa for FIXa.
Complete allogeneic hematopoietic chimerism achieved by a combined strategy of in utero hematopoietic stem cell transplantation and postnatal donor lymphocyte infusion
Authors: Hayashi Satoshi , Peranteau William H. , Shaaban Aimen F. , Flake Alan W.
Published: October 2002

In utero hematopoietic stem cell transplantation (IUHSCTx) can achieve mixed hematopoietic chimerism and donor-specific tolerance without cytoreductive conditioning or immunosuppression. The primary limitation to the clinical application of IUHSCTx has been minimal donor cell engraftment, well below therapeutic levels for most target diseases. Donor lymphocyte infusion (DLI) has been used in postnatal circumstances of mixed chimerism as targeted immunotherapy to achieve a graft-versus-hematopoietic effect and to increase levels of donor cell engraftment. In this report we demonstrate in the murine model that a combined approach of IUHSCTx followed by postnatal DLI can convert low-level, mixed hematopoietic chimerism to complete donor chimerism across full major histocompatibility complex barriers with minimal risk for graft-versus-host disease (GVHD). Time-dated embryonic day 14 (E14) to E15 Balb/c (H-2Kd, CD45.2) fetuses underwent intraperitoneal injection of 5 × 106T-cell–depleted B6 (H-2Kb, CD45.2) bone marrow cells. Chimeric recipients then received transplants at either 4 or 8 weeks of age with 1 of 3 doses (5, 15, or 30 × 106cells) of donor congenic splenocytes (B6-Ly5.2/Cr, H-2Kb, CD45.1). The response to DLI was dose dependent, with conversion to complete donor peripheral blood chimerism in 100% of animals that received high-dose (30 × 106 cells) DLI. Only 1 of 56 animals receiving this dose succumbed to GVHD. This study directly supports the potential therapeutic strategy of prenatal tolerance induction to facilitate nontoxic postnatal cellular therapy and organ transplantation, and it has broad implications for the potential treatment of prenatally diagnosed genetic disorders.
Influence of plasma immunoglobulin level on antibody synthesis
Authors: Goldammer Andreas , Derfler Kurt , Herkner Kurt , Bradwell Arthur R. , Hörl Walter H. , Haas Martin
Published: October 2002

In previous experimental animal studies it has been demonstrated that antibody depletion is not followed by increased antibody synthesis. To assess whether these results are conferrable to antibody-depleted humans, we measured free light chains (flcs) as markers of current antibody synthesis in 8 patients treated with immunoadsorption (IA) therapy. Specific and bulk immunoglobulin levels were obtained simultaneously. The mean serum flc concentration increased to the preapheresis value within 1 day and remained unchanged thereafter. Total immunoglobulin G (IgG) and specific antibody concentrations increased to pretreatment values in 88% and 43% of the patients, respectively, and remained below the original values in the others. In conclusion, the lack of increased flc synthesis after IA confirms the absence of a feedback mechanism regulating antibody synthesis. The restoration of serum IgG levels after IA, therefore, does not result from increased antibody synthesis but is probably related to changes of catabolism and immunoglobulin backflow.
Vesicle-associated membrane protein 3 (VAMP-3) and VAMP-8 are present in human platelets and are required for granule secretion
Authors: Polgár János , Chung Sul-Hee , Reed Guy L.
Published: October 2002

Secretion of platelet granules is necessary for normal hemostasis. Platelet secretion requires soluble N-ethylmaleimide–sensitive factor attachment protein (SNAP) receptor (SNARE) complex formation between different members of the syntaxin, SNAP-25, and vesicle-associated membrane protein (VAMP) gene families. Using microcapillary reverse-phase high-performance liquid chromatography–nano-electrospray tandem mass spectrometry, we identified VAMP-3 and VAMP-8 as VAMP isoforms coimmunoprecipitated from platelets with syntaxin 4. Immunoblotting experiments confirmed the presence of VAMP-3 and VAMP-8 but not VAMP-1 or VAMP-2 in platelets. To examine the effect of VAMP proteins on platelet secretion, soluble recombinant (r) VAMP-2, rVAMP-3, and rVAMP-8 were incubated with streptolysin O–permeabilized platelets. Secretion of α granules (monitored by flow cytometric measurement of P-selectin) was blocked, and dense-granule secretion (assessed by release of carbon 14–serotonin) was almost completely inhibited by rVAMP-3, whereas rVAMP-8 inhibited secretion of dense granules but not α granules. In contrast, rVAMP-2, which formed SNARE complexes in vitro, had no effect on platelet exocytosis. We conclude that VAMP-3 and VAMP-8 form SNARE complexes with platelet syntaxin 4 and are required for platelet granule secretion.
Lentiviral vectors containing the human immunodeficiency virus type-1 central polypurine tract can efficiently transduce nondividing hepatocytes and antigen-presenting cells in vivo
Authors: VandenDriessche Thierry , Thorrez Lieven , Naldini Luigi , Follenzi Antonia , Moons Lieve , Berneman Zwi , Collen Desire , Chuah Marinee K. L.
Published: October 2002

High-titer self-inactivating human immunodeficiency virus type-1 (HIV-1)–based vectors expressing the green fluorescent protein reporter gene that contained the central polypurine and termination tract and the woodchuck hepatitis virus posttranscriptional regulatory element were constructed. Transduction efficiency and biodistribution were determined, following systemic administration of these improved lentiviral vectors. In adult severe combined immunodeficiency (SCID) mice, efficient stable gene transfer was achieved in the liver (8.0% ± 6.0%) and spleen (24% ± 3%). Most transduced hepatocytes and nonhepatocytes were nondividing, thereby obviating the need to induce liver cell proliferation. In vivo gene transfer with this improved lentiviral vector was relatively safe since liver enzyme concentration in the plasma was only moderately and transiently elevated. In addition, nondividing major histocompatibility complex class II–positive splenic antigen-presenting cells (APCs) were efficiently transduced in SCID and normal mice. Furthermore, B cells were efficiently transduced, whereas T cells were refractory to lentiviral transduction in vivo. However, in neonatal recipients, lentiviral transduction was more widespread and included not only hepatocytes and splenic APCs but also cardiomyocytes. The present study suggests potential uses of improved lentiviral vectors for gene therapy of genetic blood disorders resulting from serum protein deficiencies, such as hemophilia, and hepatic disease. However, the use of liver-specific promoters may be warranted to circumvent inadvertent transgene expression in APCs. In addition, these improved lentiviral vectors could potentially be useful for genetic vaccination and treatment of perinatal cardiac disorders.
The t(14;18) defines a unique subset of diffuse large B-cell lymphoma with a germinal center B-cell gene expression profile
Authors: Huang James Z. , Sanger Warren G. , Greiner Timothy C. , Staudt Louis M. , Weisenburger Dennis D. , Pickering Diane L. , Lynch James C. , Armitage James O. , Warnke Roger A. , Alizadeh Ash A. , Lossos Izidore S. , Levy Ronald , Chan Wing C.
Published: October 2002

Recently we have identified subgroups of de novo primary diffuse large B-cell lymphoma (DLBCL) based on complementary DNA microarray-generated gene expression profiles. To correlate the gene expression profiles with cytogenetic abnormalities in these DLBCLs, we examined the occurrence of the t(14;18)(q32;q21) in the 2 distinctive subgroups of DLBCL: one with the germinal center B-cell gene expression signature and the other with the activated B cell–like gene expression signature. The t(14;18) was detected in 7 of 35 cases (20%). All 7 t(14;18)-positive cases had a germinal center B-cell gene expression profile, representing 35% of the cases in this subgroup, and 6 of these 7 cases had very similar gene expression profiles. The expression of bcl-2 and bcl-6 proteins was not significantly different between the t(14;18)-positive and -negative cases, whereas CD10 was detected only in the group with the germinal center B-cell expression profile, and CD10 was most frequently expressed in the t(14;18)-positive cases. This study supports the validity of subdividing DLBCL into 2 major subgroups by gene expression profiling, with the t(14;18) being an important event in the pathogenesis of a subset of DLBCL arising from germinal center B cells. CD10 protein expression is useful in identifying cases of DLBCL with a germinal center B-cell gene expression profile and is often expressed in cases with the t(14;18).
CD4+ and CD8+ anergic T cells induced by interleukin-10–treated human dendritic cells display antigen-specific suppressor activity
Authors: Steinbrink Kerstin , Graulich Edith , Kubsch Sebastian , Knop Jürgen , Enk Alexander H.
Published: October 2002

Interleukin-10 (IL-10)–treated dendritic cells (DCs) induce an alloantigen- or peptide-specific anergy in various CD4+ and CD8+ T-cell populations. In the present study, we analyzed whether these anergic T cells are able to regulate antigen-specific immunity. Coculture experiments revealed that alloantigen-specific anergic CD4+ and CD8+ T cells suppressed proliferation of syngeneic T cells in a dose-dependent manner. The same effect was observed when the hemagglutinin-specific CD4+T-cell clone HA1.7 or tyrosinase-specific CD8+ T cells were cocultured with anergic T cells of the same specificity. Anergic T cells did not induce an antigen-independent bystander inhibition. Suppression was dependent on cell-to-cell contact between anergic and responder T cells, required activation by antigen-loaded DCs, and was not mediated by supernatants of anergic T cells. Furthermore, anergic T cells displayed an increased extracellular and intracellular expression of cytotoxic T-lymphocye antigen (CTLA)–4 molecules, and blocking of the CTLA-4 pathway restored the T-cell proliferation up to 70%, indicating an important role of the CTLA-4 molecule in the suppressor activity of anergic T cells. Taken together, our experiments demonstrate that anergic T cells induced by IL-10–treated DCs are able to suppress activation and function of T cells in an antigen-specific manner. Induction of anergic T cells might be exploited therapeutically for suppression of cellular immune responses in allergic or autoimmune diseases with identified (auto) antigens.
The Stat5-RARα fusion protein represses transcription and differentiation through interaction with a corepressor complex
Authors: Maurer Alexander B. , Wichmann Christian , Gross Alexandra , Kunkel Hana , Heinzel Thorsten , Ruthardt Martin , Groner Bernd , Grez Manuel
Published: October 2002

The transcription factor Stat5 mediates the cellular response to activation of multiple cytokine receptors involved in the regulation of proliferation and differentiation of hematopoietic cells. Recently, the human Stat5 gene was found to be translocated to the RARα gene in a patient with acute promyelocytic leukemia indicating that Stat5 might also play a role in cellular transformation. We investigated the mechanism by which Stat5 might exert this function and studied the biochemical and cellular functions of fusion proteins comprising Stat5 and RARα. The expression of Stat5-RARα causes the transcriptional repression of gene transcription, a process that requires the coiled-coil domain of Stat5 (amino acid positions 133-333). Oligomerization of this domain in the Stat5-RARα fusion protein leads to stable binding of the corepressor SMRT independent of all-trans retinoic acid (ATRA) stimulation and is accompanied by an impaired response to differentiation signals in hematopoietic cells. This inhibitory effect on myeloid differentiation cannot be overcome by simultaneous coexpression of RARα. We conclude that Stat5 is capable of interacting with a corepressor complex that alters the pattern of corepressor binding to RARα and its dissociation in response to ATRA stimulation, leading to enhanced repressor activity and a block of hematopoietic differentiation.
Intrathymic and extrathymic development of human plasmacytoid dendritic cell precursors in vivo
Authors: Weijer Kees , Uittenbogaart Christel H. , Voordouw Arie , Couwenberg Franka , Seppen Jurgen , Blom Bianca , Vyth-Dreese Florry A. , Spits Hergen
Published: October 2002

The development of plasmacytoid dendritic cells (pDC2) from human CD34+ stem cells in vivo was studied in RAG-2−/− interleukin (IL)-2Rγ−/− mice that lack functional T and B cells and natural killer cells. CD34+ cells isolated from fetal liver or thymus were labeled with 5- and 6-carboxyfluorescein diacetate succinimidyl ester (CFSE) and were injected into a human thymus grafted subcutaneously in the RAG-2−/− IL-2Rγ−/− mice. One to 4 weeks later the CFSE label was found not only in T cells but also in CD123+/high CD4+CD45RA+ pDC2, indicating that the CD34+ cells can develop into pDC2 within a thymus. In addition to pDC2, CFSE-labeled dendritic cells with a mature phenotype, determined by the cell surface markers CD11c, CD83, and CD80, were found in the injected human thymus graft. pDC2 was not found in the periphery of mice carrying a human thymic graft, indicating that the intrathymic pDC2 failed to emigrate from the thymus. We also demonstrate that pDC2 can develop outside the thymus because relatively high percentages of pDC2 were found in the periphery after the intravenous injection of CD34+CD38−fetal liver cells in RAG-2−/− IL-2Rγ−/−mice without a human thymus graft. These data indicate that the thymus and the peripheral pDC2 develop independently of each other.
Identification of a myeloid intrathymic pathway of dendritic cell development marked by expression of the granulocyte macrophage–colony-stimulating factor receptor
Authors: de Yébenes Virginia G. , Carrasco Yolanda R. , Ramiro Almudena R. , Toribio Marı́a L.
Published: October 2002

In this study, the finding that a significant proportion of all dendritic cells (DCs) resident in vivo in the human postnatal thymus displayed a myeloid-related phenotype prompted us to re-examine the developmental origin of thymic DCs, a cell type hitherto considered to represent a homogeneous lymphoid-derived population. We show here that these novel intrathymic DCs are truly myeloid, as they arise from CD34+ early thymic progenitors through CD34lointermediates which have lost the capacity to generate T cells, but display myelomonocytic differentiation potential. We also demonstrate that phenotypically and functionally equivalent myeloid precursors devoid of T-cell potential do exist in vivo in the postnatal thymus. Moreover, although interleukin 7 (IL-7) supports the generation of such myeloid intermediates, we show that their developmental branching from the main intrathymic T-cell pathway is linked to the up-regulation of the myelomonocytic granulocyte macrophage–colony-stimulating factor (GM-CSF) receptor, to the down-regulation of the IL-7 receptor and to the lack of pre–T-cell receptor α (pTα) gene transcriptional activation. Taken together, these data challenge the current view that the thymus is colonized by a lymphoid-restricted progenitor and provide evidence that a more immature precursor population with lymphoid and myelomonocytic potential is actually seeding the human postnatal thymus.
Caspase-catalyzed cleavage and activation of Mst1 correlates with eosinophil but not neutrophil apoptosis
Authors: De Souza Patricia M. , Kankaanranta Hannu , Michael Ashour , Barnes Peter J. , Giembycz Mark A. , Lindsay Mark A.
Published: October 2002

We have examined the role of caspase-mediated cleavage of the Ste20-like kinases, mammalian sterile 20-like 1 and 2 (Mst1/Mst2), in the mechanism of human eosinophil and neutrophil apoptosis. Initial measurements of kinase activity, using myelin basic protein (MBP) as a substrate in “in-gel” renaturation assays, showed that constitutive eosinophil and neutrophil apoptosis were associated temporally with the activation of a 36-kd MBP kinase (p36 MBPK) and a 34-kd MBP kinase (p34 MBPK), respectively. A constitutively active 63-kd MBP kinase (p63 MBPK) was also detected in freshly prepared eosinophils but not neutrophils, whose activity was transiently augmented during spontaneous apoptosis. Immunoblotting studies demonstrated the expression of Mst1 and Mst2 in eosinophils but not neutrophils whereas immunoprecipitation studies identified the p63 MBPK activity as being Mst1 and Mst2 and showed that the p36 MBPK activity represented the N-terminal catalytic fragment of Mst1. A role for the p36 MBPK in eosinophil cell death was supported by studies showing increased activation upon exposure to the proapoptotic Fas/CD95-activating antibody, CH-11, and attenuation in the presence of the survival-promoting cytokine, interleukin-5. Furthermore, spontaneous and Fas-induced activation of p36 MBPK was inhibited by catalase and the general caspase inhibitor, z-Asp-CH2-DCB, at concentrations that suppressed eosinophil apoptosis. These studies therefore implicate a role for caspase- and H2O2-mediated cleavage of the Mst1 and the subsequent release of the 36-kd catalytic fragment in the mechanism of eosinophil apoptosis. In contrast, neutrophil apoptosis occurs independently of Mst1 and Mst2 but instead is correlated with the activation of an as-yet-unidentified 34-kd MBPK.
Air pollution and hospital admissions for respiratory conditions in Rome, Italy
Authors: Fusco D. , Forastiere F. , Michelozzi P. , Spadea T. , Ostro B. , Arcà M. , Perucci C.A.
Published: October 2002

Most of the evidence regarding the association between particulate air pollution and emergency room visits or hospital admissions for respiratory conditions and asthma comes from the USA. European time-series analyses have suggested that gaseous air pollutants are important determinants of acute hospitalization for respiratory conditions, at least as important as particulate mass. The association between daily mean levels of suspended particles and gaseous pollutants (sulphur dioxide, nitrogen dioxide, carbon monoxide, ozone) was examined. The daily emergency hospital admissions for respiratory conditions in the metropolitan area of Rome during 1995–1997 were also recorded.

Daily counts of hospital admissions for total respiratory conditions (43 admissions·day−1), acute respiratory infections including pneumonia (18·day−1), chronic obstructive pulmonary disease (COPD) (13·day−1), and asthma (4.5·day−1) among residents of all ages and among children (0–14 yrs) were analysed. The generalized additive models included spline smooth functions of the day of study, mean temperature, mean humidity, influenza epidemics, and indicator variables for day of the week and holidays.

Total respiratory admissions were significantly associated with same-day level of NO2(2.5% increase per interquartile range (IQR) change, 22.3 µg·m−3) and CO (2.8% increase per IQR, 1.5 mg·m−3). No effect was found for particulate matter and SO2, whereas O3was associated with admissions only among children (lag 1, 5.5% increase per IQR, 23.9 µg·m3). The effect of NO2was stronger on acute respiratory infections (lag 0, 4.0% increase) and on asthma among children (lag 1, 10.7% increase). The admissions for all ages for asthma and COPD were associated only with same-day level of CO (5.5% and 4.3% increase, respectively). Multipollutant models confirmed the role of CO on all respiratory admissions, including asthma and COPD, and that of NO2on acute respiratory infections. Among children, O3remained a strong indicator of acute respiratory infections.

Carbon monoxide and photochemical pollutants (nitrogen dioxide, ozone) appear to be determinants of acute respiratory conditions in Rome. Since carbon monoxide and nitrogen dioxide are good indicators of combustion products from traffic related sources, the detected effect may be due to unmeasured fine and ultrafine particles.
The sleep apnoea/hypopnoea syndrome depresses waking vagal tone independent of sympathetic activation
Authors: Hilton M.F. , Chappell M.J. , Bartlett W.A. , Malhotra A. , Beattie J.M. , Cayton R.M.
Published: October 2002

The modest daytime hypertension and sympathetic upregulation associated with the sleep apnoea/hypopnoea syndrome (SAHS), does not explain the relatively large increased risk of cardiac morbidity and mortality in the SAHS patients population. Therefore, efferent vagal and sympathetic activity was evaluated during wakefulness in SAHS subjects and matched healthy controls, in order to determine if vagal downregulation may play a role in the aetiology of cardiac disease in the SAHS.

The awake autonomic nervous system function of 15 male subjects, with mild-to-moderate SAHS was compared to that of 14 healthy controls matched for age, body mass index, gender and blood pressure. All subjects were free from comorbidity. Vagal activity was estimated from measurements of heart rate variability high frequency power (HF) and sympathetic activity was measured from urine catecholamine excretion.

The %HF power was significantly (p<0.03) reduced in SAHS patients (10±1.6 (mean±sem)) as compared to controls (17±3). In addition, HF power correlated with the apnoea/hypopnoea index in the SAHS subjects (R=−0.592, p=0.02). There was no statistically significant difference in the daytime excretion of nonadrenaline between control (242±30 nmol·collection−1) and SAHS (316±46 nmol·collection−1) subjects (p=0.38).

In these sleep apnoea/hypopnoea syndrome patients there was limited evidence of increased waking levels of urine catecholamines. The principal component altering waking autonomic nervous system function, in the sleep apnoea/hypopnoea syndrome subjects, was a reduced daytime efferent vagal tone.
Vitamin E attenuates the injurious effects of bioactive phospholipids on human ciliated epitheliumin vitro
Authors: Feldman C. , Anderson R. , Theron A.J. , Steel H.C. , van Rensburg C.E.J. , Cole P.J. , Wilson R.
Published: October 2002

Bioactive phospholipids (PL), particularly lysophosphatidylcholine (LPC), are being increasingly implicated in the pathogenesis of various acute and chronic inflammatory disorders, particularly those of the airways, while there is emerging evidence that vitamin E may function as a natural antagonist of these lipid mediators of inflammation. The aims of this study were to document the effects of vitamin E on the inhibition of ciliary beating and damage to structural integrity of human ciliated epithelium induced by the PL, platelet-activating factor (PAF), lyso-PAF and LPCin vitroin relation to the anti-oxidative and membrane-stabilizing properties of the vitamin.

Ciliary beat frequency was measured by a phototransistor technique, and damage to structural integrity assessed by a visual-scoring index, while superoxide production by polymorphonuclear leukocytes and membrane-stabilizing potential were measured using lucigenin-enhanced chemiluminescence and haemolytic procedures, respectively.

All three PL caused inhibition of ciliary beating and structural damage to human ciliated epithelium by membrane-directed cytotoxic mechanisms, which were potentiated by human polymorphonuclear leukocytes due to induction of oxidant-mediated injury. Both direct and phagocyte-inflicted epithelial injury was attenuated by vitamin E. In haemolytic and chemiluminescence assays, vitamin E neutralized both the membrane-destabilizing and pro-oxidative actions of all three PL, while spectrophotometric analysis of mixtures of vitamin E with PAF, lyso-PAF and LPC revealed alterations in peak intensity, as well as peak shifts, indicative of physicochemical interactions between the vitamin and the PL.

Vitamin E status may be a determinant of susceptibility to phospholipid-mediated airway inflammation and damage.
Effect of airway opening manoeuvres on thoraco-abdominal asynchrony in anaesthetized children
Authors: Reber A. , Bobbià S.A. , Hammer J. , Frei F.J.
Published: October 2002

Thoraco-abdominal asynchrony is frequently encountered during inhalation anaesthesia in children with adenotonsillar hypertrophy causing an upper airway obstruction. The study goal was to evaluate the impact of different airway opening manoeuvres on thoraco-abdominal asynchrony as a measure of airway obstruction.

Thirty anaesthetized children (aged 2–8 yrs; sevoflurane 3% in 50% oxygen/nitrous oxide) were studied prior to elective adenotonsillectomy using respiratory inductance plethysmography to record ribcage and abdominal wave forms as a basis for calculation of the phase angle. Five airway situations were compared: 1) baseline (unsupported mandible); 2) chin lift; 3) chin lift combined with continuous positive airway pressure of 10 cmH2O; 4) jaw thrust; and 5) jaw thrust combined with continuous positive airway pressure of 10 cmH2O.

Three children had complete upper airway obstruction at baseline and were excluded from the study. With chin lift, thoraco-abdominal asynchrony improved in three patients, worsened in three patients and was unchanged in 21 patients. Additional continuous positive airway pressure during chin lift did not markedly reduce thoraco-abdominal asynchrony (phase angle 89±43°, p=0.33). Jaw thrust resulted in a significant decrease of the phase angle (from 106±53° at baseline to 65±49°, p<0.01); when combined with continuous positive airway pressure, no further effect on thoraco-abdominal asynchrony was found (72±44°).

In anaesthetized children with adenotonsillar hypertrophy, airway opening manoeuvres have distinct effects on thoraco-abdominal asynchrony. Delivery of continuous positive airway pressure and jaw thrust can be the first airway opening manoeuvres to improve breathing patterns. Chin lift without additional continuous positive airway pressure should be used with caution in these patients because it may convert partial into almost complete airway obstruction.
Attenuation by oralN-acetylcysteine of bleomycin-induced lung injury in rats
Authors: Cortijo J. , Cerdá-Nicolás M. , Serrano A. , Bioque G. , Estrela J.M. , Santangelo F. , Esteras A. , Llombart-Bosch A. , Morcillo E.J.
Published: October 2002

Antioxidant therapy may be useful in diseases with impaired oxidant-antioxidant balance such as pulmonary fibrosis. This study examines the effect ofN-acetylcysteine (NAC) on bleomycin-induced lung fibrosis in rats.

NAC (3 mmol·kg−1; oral) was given daily from 1 week prior to a single intratracheal instillation of bleomycin (2.5 U·kg−1) or saline, until 14 days postinstillation.

NAC partially decreased the augmented collagen deposition in bleomycin-exposed rats (hydroxyproline content was 4,354±386 and 3,416±326 µg·lung−1in vehicle-treated and NAC-treated rats, respectively; p<0.05). The histological assessment using a semiquantitative score showed less collagen deposition and inflammatory cells in NAC-treated rats compared to those receiving bleomycin alone. NAC failed to inhibit the bleomycin-induced increases in lung wet weight and in cell counts and protein levels of bronchoalveolar lavage fluid, but significantly increased total glutathione and taurine levels in bronchoalveolar lavage fluid.

These results indicate that oralN-acetylcysteine improves the pulmonary antioxidant protection and may be useful in reducing lung damage produced by bleomycin.
The German cystic fibrosis quality assurance project: clinical features in children and adults
Authors: Wiedemann B. , Steinkamp G. , Sens B. , Stern M.
Published: October 2002

Cystic fibrosis (CF) is a complex disease which requires interdisciplinary care in specialized CF centres. In Germany, 97 paediatric and adult outpatient clinics agreed to report clinical data of their patients to a newly established registry, the Cystic Fibrosis Quality Assurance (CFQA) project. This article characterizes the design of the CFQA and the health status of the patients enrolled by the end of 1997.

Data from 4,306 patients reported to the CFQA project were analysed. Nutritional status and lung function of the patients were examined as well as the use of specific therapeutic interventions.

Mean age of all 4,182 patients alive by the end of 1997 was 15.7 yrs (maximum, 58 yrs), and 35.8% of patients were >18.0 yrs of age. One-third of the CF population were treated in the nine largest centres (each caring for >100 patients). Abnormal nutritional status (weight-for-height >90% of predicted or body mass index <19.0 kg·m2, respectively) was observed in 26.8% of children and adolescents and in 38.3% of adults. Lung function was abnormal (forced expiratory volume in one second <80% predicted) in the majority of adults (83.9%) and in 42.5% of the younger patients. The mortality rate was 1.4 of 100 patients in 1997. No clear association of clinical status with centre size was observed.

The clinical features of patients treated in German cystic fibrosis centres were generally comparable to those reported from other countries, although improvements are certainly warranted. The Cystic Fibrosis Quality Assurance project represents an important tool for future progress in the quality of cystic fibrosis care.
The effects of an anti-CD4 monoclonal antibody, keliximab, on peripheral blood CD4+ T-cells in asthma
Authors: Kon O.M. , Sihra B.S. , Loh L.C. , Barkans J. , Compton C.H. , Barnes N.C. , Larché M. , Kay A.B.
Published: October 2002

CD4+ T-cells are likely to be involved as a source of pro-inflammatory cytokines in asthma. This study assessed the effects of an infusion of keliximab (IDEC CE9.1), an anti-CD4+ monoclonal antibody, on peripheral blood CD4+ T-cells in corticosteroid-dependent asthmatics.

Three cohorts of patients (termed C0.5: n=6, C1.5: n=5, and C3.0: n=5) received a single infusion of 0.5, 1.5 or 3.0 mg·kg−1, respectively, with a fourth receiving placebo (Cpl: n=6), and were followed-up for 4 weeks. By flow cytometry in peripheral blood, pre- and postinfusion assessment was made of: a) CD4 and CD8 counts and mean fluorescence; b) CD25, human leukocyte antigen-DR (HLA-DR), CD45RO and CD45RA expression on CD4+ T-cells; and c) interferon (IFN)-γ, interleukin (IL)-4 and IL-5 expression in CD4+ T-cells. Keliximab'sin vitroeffects on allergen-specific peripheral blood mononuclear cells (PBMC) proliferation in atopic asthmatics were also evaluated.

There was a significant increase in lung function (peak expiratory flow rate) in the C3.0group. Following infusion in C0.5, C1.5and C3.0but not Cpl: 1) the CD4, but not CD8 count was significantly decreased; 2) there was total loss of Leu3a staining; 3) there were significant reductions in the mean fluorescence of OKT4 binding; and 4) there were significant reductions in the numbers of CD25, HLA-DR, CD45RO and CD45RA/CD4+ cells. There were no changes in CD4+ cell expression of IFN-γ, IL-4 or IL-5. Keliximab caused a significant reduction in T-cell proliferation as compared to a control monoclonal antibody.

Keliximab, as an anti-CD4 monoclonal antibody, leads to a transient reduction in the number of CD4+ T-cells and modulation of CD4+ receptor expression in severe asthmatics. The effects of keliximab may be mediated through a decrease in CD4+ surface expression and T-lymphocyte numbers, in addition to a reduction in allergen-induced proliferation.
Fluticasone and salmeterol downregulatein vitro, fibroblast proliferation and ICAM-1 or H-CAM expression
Authors: Silvestri M. , Fregonese L. , Sabatini F. , Dasic G. , Rossi G.A.
Published: October 2002

β2-adrenoreceptor agonists have pharmacological properties that may suggest an inhibitory effect on various aspects of the inflammatory and repair processes that characterize asthma.

Since fibroblasts express β2-adrenoreceptors, the effects of different concentrations (0.1–100 nM) of fluticasone propionate (FP), salmeterol (S) and their combination (FP+S) on lung fibroblast proliferation and adhesion molecule expression were evaluated.

Stimulation of human foetal lung fibroblasts with a fibrogenic cytokine, basic fibroblast growth factor (bFGF), resulted in a [methyl-3H] thymidine ([3H]TdR) uptake, four-fold higher than that of control cultures (p=0.0001) and was significantly inhibited by S, at all the concentrations tested (0.1–100 nM; p<0.05). No changes in bFGF-induced cell proliferation were observed in the presence of FP (0.1–100 nM; p>0.05, all comparisons). In addition, the association FP+S did not improve the inhibitory activity of S alone (p>0.05, each comparison). An upregulation of intercellular adhesion molecule-1 (ICAM-1) expression was induced by tumour necrosis factor-α (TNF-α) (p=0.0004), but not by interleukin-4 (IL-4) (p>0.05), while none of the two cytokines were able to increase hyaluronic-cellular adhesion molecule (H-CAM) expression by lung fibroblasts (p>0.05). A significant downregulation of ICAM-1 or H-CAM expression was demonstrated in the presence of FP or S, at all concentrations tested (0.1–100 nM; p<0.01, each comparison). Interestingly, S (10 nM and 100 nM) was able to enhance the inhibitory activity of FP on ICAM-1 expression (p<0.01), but not on H-CAM expression (p>0.1).

These results show that in human foetal lung fibroblasts, fluticasone propionate and salmeterol are effective in modulatingin vitro, different lung fibroblast biological functions that are likely to be involved in airway remodelling.
Host immune response toChlamydia pneumoniaeheat shock protein 60 is associated with asthma
Authors: Huittinen T. , Hahn D. , Anttila T. , Wahlström E. , Saikku P. , Leinonen M.
Published: October 2002

Chlamydia pneumoniaeinfection has been associated with asthma. It has also been suggested that heat shock protein 60 (Hsp60) belonging to a class of highly conserved proteins may play a role in the pathogenesis of chlamydial infections. The purpose was to study whether the host immune response toC. pneumoniaeHsp60 is associated with asthma and decreased pulmonary function.

An enzyme immunoassay was used to measure immunoglobulin-(Ig)A and IgG antibodies against recombinantC. pneumoniaeHsp60 and human Hsp60 in a study group consisting of 24 cases of recently symptomatic asthma and 62 nonasthmatic controls.

A strong (r=0.50) and significant (p<0.001) correlation was observed betweenC. pneumoniaeand human Hsp60 IgA antibodies, but onlyC. pneumoniaeHsp60 IgA antibodies were significantly associated with asthma (p=0.02). Pulmonary function, as measured by forced expiratory volume in one second, also inversely correlated (r=−0.23, p=0.04) with the quantity ofC. pneumoniaeHsp60 IgA antibodies, suggesting an association with the severity of pulmonary obstruction.

By showing an association ofChlamydia pneumoniaeheat shock protein 60 immunoglobulin A antibodies with asthma, the results support the hypothesis of an association betweenChlamydia pneumoniaeinfection and asthma and support the need for further investigations on the role of heat shock protein 60 in the pathogenesis of asthma.
Nasal potential difference measurements in patients with atypical cystic fibrosis
Authors: Wilschanski M. , Famini H. , Strauss-Liviatan N. , Rivlin J. , Blau H. , Bibi H. , Bentur L. , Yahav Y. , Springer H. , Kramer M.R. , Klar A. , Ilani A. , Kerem B. , Kerem E.
Published: October 2002

The diagnosis of cystic fibrosis (CF) is based on characteristic clinical and laboratory findings. However, a subgroup of patients present with an atypical phenotype that comprises partial CF phenotype, borderline sweat tests and one or even no common cystic fibrosis transmembrane conductance regulator (CFTR) mutations. The aim of this study was to evaluate the role of nasal potential difference (PD) measurements in the diagnosis of CF patients with an atypical presentation and in a population of patients suspected to have CF.

Nasal PD was measured in 162 patients from four different groups: patients with classical CF (n=31), atypical phenotype (n=11), controls (n=50), and patients with questionable CF (n=70). The parameter, or combination of nasal PD parameters was calculated in order to best discriminate all CF patients (including atypical CF) from the non-CF group.

The patients with atypical CF disease had intermediate values of PD measurements between the CF and non-CF groups. The best discriminate model that assigned all atypical CF patients as CF used: e(response to chloride-free and isoproterenol/response to amiloride)with a cut-off >0.70 to predict a CF diagnosis. When this model was applied to the group of 70 patients with questionable CF, 24 patients had abnormal PD similar to the atypical CF group. These patients had higher levels of sweat chloride concentration and increased rate of CFTR mutations.

Nasal potential difference is useful in diagnosis of patients with atypical cystic fibrosis. Taking into account both the sodium and chloride transport elements of the potential difference allows for better differentiation between atypical cystic fibrosis and noncystic fibrosis patients. This calculation may assist in the diagnostic work-up of patients whose diagnosis is questionable.
Molecular physiology of oxygen-sensitive potassium channels
Authors: Patel A.J. , Honoré E.
Published: October 2002

Physiological adaptation to acute hypoxia involves oxygen-sensing by a variety of specialized cells including carotid body type I cells, pulmonary neuroepithelial body cells, pulmonary artery myocytes and foetal adrenomedullary chromaffin cells.

Hypoxia induces depolarization by closing a specific set of potassium channels and triggers cellular responses. Molecular biology strategies have recently allowed the identification of the K+channel subunits expressed in these specialized cells.

Several voltage-gated K+channel subunits comprising six transmembrane segments and a single pore domain (Kv1.2, Kv1.5, Kv2.1, Kv3.1, Kv3.3, Kv4.2 and Kv9.3) are reversibly blocked by hypoxia when expressed in heterologous expression systems. Additionally, the background K+channel subunit TASK-1, which comprises four transmembrane segments and two pore domains, is also involved in both oxygen- and acid-sensing in peripheral chemoreceptors.

Progress is currently being made to identify the oxygen sensors. Regulatory β subunits may play an important role in the modulation of Kv channel subunits by oxygen.