bluuebunny/crossref_metadata_2025 huggingface dataset:
Characterization of B‐ and T‐cell responses and HLA‐DR4 binding motifs of the latex allergen Hev b 6.01 (prohevein) and its post‐transcriptionally formed proteins Hev b 6.02 and Hev b 6.03
Authors: Raulf‐Heimsoth M. , Rozynek P. , Brüning T. , Rihs H.‐P.
Published: June 2004

Background:  Multiple immunoglobulin E (IgE)‐binding proteins in natural rubber latex extracts have been identified. In the case of Hev b 6 a differentiation was made between the precursor protein prohevein (Hev b 6.01) and its two post‐transcriptionally formed proteins, the N‐terminal hevein (Hev b 6.02) and the C‐terminal domain (Hev b 6.03). All three components act as independent allergens. The aim of this study was a detailed analysis of the T‐cell responses and the IgE‐binding capacity of Hev b 6.01, Hev b 6.02 and Hev b 6.03 by using these allergens as recombinant maltose‐binding fusion (MBP) proteins and the usage of synthetic modified hevein peptides.

Methods:  Latex‐allergic health care workers (HCWs) suffering from rhinitis, conjunctivitis, contact urticaria and/or asthma with increased specific IgE‐antibodies to latex were tested for their IgE‐binding capacity and T‐cell reactivity (by proliferation response) to the recombinant MBP‐rHev b 6.01, MBP‐rHev b 6.02, MBP‐rHev b 6.03, to native Hev b 6.02, to modified hevein peptides and wheat germ agglutinin (WGA). For testing of the human leucocyte antigen (HLA) class II restriction of MBP‐rHev b 6.01 induced peripheral blood mononuclear cell (PBMC) responses, monoclonal antibodies against HLA‐DR, HLA‐DP or HLA‐DQ were added.

Results:  Seventeen of 18 (94%) serum samples from latex‐allergic HCWs had increased levels of specific IgE to MBP‐rHev b 6.01, 16 (89%) to MBP‐rHev b 6.02 and 13 (72%) to MBP‐rHev b 6.03. A significant difference existed between the specific IgE‐values of MBP‐rHev b 6.02 and MBP‐rHev b 6.03 (P < 0.01). Proliferation responses of PBMC of the same 18 latex‐allergic patients were positive for MBP‐rHev b 6.01 and MBP‐rHev b 6.03 in 83 and 67% of the tested PBMC suspension, whereas the proliferation responses induced with MBP‐rHev b 6.02 or native Hev b 6.02 were very low (5.6 and 22.2%). Sera from nine additional latex‐allergic patients showed specific IgE binding to the native Hev b 6.02, but none of these sera showed specific IgE binding to the modified Hev b 6.02‐peptides [whereby all eight cysteine residues were substituted by serine (C → S) or by alanine (C → A)]. Proliferation responses induced by the modified Hev b 6.02 peptides were not significantly different from that induced by Hev b 6.02. Potential HLA‐DR4Dw4(DRB1*0401)‐restricted T‐cell epitopes of Hev b 6.01 predicted by two computer algorithms were only found in the Hev b 6.03‐part of Hev b 6.01.

Conclusion:  In the Hev b 6.01 precursor the regions responsible for IgE binding and those for inducing the T‐cell proliferation responses are settled in different parts of the protein. The Hev b 6.02 domain is responsible for IgE binding and carries discontinuous B‐cell epitopes whereas Hev b 6.03 is a better inducer of a proliferation response and contains HLA‐DR4‐binding motifs.
Allergic inflammation induced by a Penicillium chrysogenum conidia‐associated allergen extract in a murine model
Authors: Schwab C. J. , Cooley J. D. , Jumper C. J. , Graham S. C. , Straus D. C.
Published: June 2004

Background:  Recent evidence has shown that viable conidia from the fungus Penicillium chrysogenum induce allergic effects in mice. The present study was conducted to determine the specific allergic dose response of C57BL/6 mice to the protease extract, Pen ch, isolated from viable P. chrysogenum conidia.

Methods:  Mice were treated with primary intraperitoneal (IP) injections of 10 or 100 μg of Pen ch adsorbed to alum, followed by weekly IP injections of 0.1, 1.0, or 10.0 μg Pen ch with alum for 4 weeks, and with 10.0 μg of Pen ch by intranasal (IN) inoculations the final 2 weeks before killing.

Results:  Intraperitoneal injections of 10 and 100 μg of Pen ch for 5 weeks followed by 2 weeks of IN instillation of 10 μg induced significant increases of total serum immunoglobulin (Ig)E and IgG1. Bronchoalveolar lavage cell counts revealed increased numbers of eosinophils and neutrophils. Histopathological examination of lungs detected perivascular inflammation by eosinophils and neutrophils and increased mucous production.

Conclusions:  The data presented in this study indicate that sensitization to protease allergens released by viable P. chrysogenum conidia in vivo induce a strong allergic inflammatory response in a murine model, which could have implications for people exposed to high levels of conidia of this organism.
Type I latex allergy in health care workers with latex‐induced contact urticaria syndrome: a follow‐up study
Authors: Nettis E. , Colanardi M. C. , Ferrannini A.
Published: June 2004

Background:  Latex allergy is an important occupational health issue among health care workers (HCWs). Secondary prevention in sensitized/allergic individuals involves avoiding exposure to NRL products.

Aims of the study:  The aim of this follow‐up study is to determine the long‐term health consequences in HCWs with type I latex allergy with latex‐related contact urticaria syndrome, of providing appropriate information and practical avoidance education.

Methods:  Seventeen HCWs with latex‐induced contact urticaria syndrome, as ascertained by the glove use test, were investigated. Initial and follow‐up visits included: a detailed questionnaire, skin prick test (SPT) with glove eluates and with commercial latex extract, SPT with common inhalant and food extracts, serum specific immunoglobulin (Ig)E to latex and some foods and the glove use test.

Results:  On re‐examination, 11 (64.7%) subjects showed positive SPTs to extemporaneous extract and 10 (58.8%) patients showed a positive SPT to commercial extract. Of the nine patients with detectable levels of serum latex specific IgE at first evaluation, four (44.4%) became negative and four were assigned to at least one class lower. Only one (11.1%) employee had higher radioallergosorbent test values than those at the latex allergy diagnosis. At follow‐up, the 17 individuals had positive latex challenge results, although the duration of exposure causing a reaction increased.

Conclusion:  Our study shows that preventive measures are sufficient to induce a reduction of sensitization. Continued avoidance is needed to prevent re‐sensitization or adverse reactions on re‐exposure.
Efficacy and tolerability of anti‐immunoglobulin E therapy with omalizumab in patients with concomitant allergic asthma and persistent allergic rhinitis: SOLAR
Authors: Vignola A. M. , Humbert M. , Bousquet J. , Boulet L‐P. , Hedgecock S. , Blogg M. , Fox H. , Surrey K.
Published: June 2004

Background:  Anti‐IgE therapy could be particularly beneficial for patients with concomitant disease as it targets a common factor in both diseases. The aim of this study was to evaluate the efficacy and safety of omalizumab in patients with concomitant moderate‐to‐severe asthma and persistent allergic rhinitis.

Methods:  This multicentre, randomized, double‐blind, parallel‐group, placebo‐controlled trial evaluated the safety and efficacy of omalizumab. A total of 405 patients (12–74 years) with a stable treatment (≥ 400 μg budesonide Turbuhaler®) and ≥ 2 unscheduled medical visits for asthma during the past year or ≥ 3 during the past 2 years were enrolled. Patients received omalizumab (≥ 0.016 mg/kg/IgE [IU/ml] per 4 weeks) or placebo for 28 weeks.

Results:  Fewer patients treated with omalizumab experienced asthma exacerbations (20.6%) than placebo‐treated patients (30.1%), P = 0.02. A clinically significant (≥ 1.0 point) improvement in both Asthma Quality of Life Questionnaire and Rhinitis Quality of Life Questionnaire occurred in 57.7% of omalizumab patients compared with 40.6% of placebo patients (P < 0.001). Omalizumab reduced Wasserfallen symptom scores for asthma (P = 0.023), rhinitis (P < 0.001) and the composite asthma/rhinitis scores (P < 0.001) compared with placebo. Serious adverse events were observed in 1.4% of omalizumab‐treated patients and 1.5% of placebo‐treated patients.

Conclusion:  Omalizumab is well tolerated and effective in preventing asthma exacerbations and improving quality of life in patients with concomitant asthma and persistent allergic rhinitis.
α‐Conotoxins as tools for the elucidation of structure and function of neuronal nicotinic acetylcholine receptor subtypes
Authors: Nicke Annette , Wonnacott Susan , Lewis Richard J.
Published: June 2004

Cone snails comprise ≈ 500 species of venomous molluscs, which have evolved the ability to generate multiple toxins with varied and often exquisite selectivity. One class, the α‐conotoxins, is proving to be a powerful tool for the differentiation of nicotinic acetylcholine receptors (nAChRs). These comprise a large family of complex subtypes, whose significance in physiological functions and pathological conditions is increasingly becoming apparent. After a short introduction into the structure and diversity of nAChRs, this overview summarizes the identification and characterization of α‐conotoxins with selectivity for neuronal nAChR subtypes and provides examples of their use in defining the compositions and function of neuronal nAChR subtypes in native vertebrate tissues.
Kinetics of the inhibition of neutrophil proteinases by recombinant elafin and pre‐elafin (trappin‐2) expressed in Pichia pastoris
Authors: Zani Marie‐Louise , Nobar Shila M. , Lacour Sandrine A. , Lemoine Soazig , Boudier Christian , Bieth Joseph G. , Moreau Thierry
Published: June 2004

Elafin and its precursor, trappin‐2 or pre‐elafin, are specific endogenous inhibitors of human neutrophil elastase and proteinase 3 but not of cathepsin G. Both inhibitors belong, together with secretory leukocyte protease inhibitor, to the chelonianin family of canonical protease inhibitors of serine proteases. A cDNA coding either elafin or its precursor, trappin‐2, was fused in frame with yeast α‐factor cDNA and expressed in the Pichia pastoris yeast expression system. Full‐length elafin or full‐length trappin‐2 were secreted into the culture medium with high yield, indicating correct processing of the fusion proteins by the yeast KEX2 signal peptidase. Both recombinant inhibitors were purified to homogeneity from concentrated culture medium by one‐step cationic exchange chromatography and characterized by N‐terminal amino acid sequencing, Western blot and kinetic studies. Both recombinant elafin and trappin‐2 were found to be fast‐acting inhibitors of pancreatic elastase, neutrophil elastase and proteinase 3 with kass values of 2–4 × 106 m−1·s−1, while dissociation rate constants kdiss were found to be in the 10−4 s−1 range, indicating low reversibility of the complexes. The equilibrium dissociation constant Ki for the interaction of both recombinant inhibitors with their target enzymes was either directly measured for pancreatic elastase or calculated from kass and kdiss values for neutrophil elastase and proteinase 3. Ki values were found to be in the 10−10 molar range and virtually identical for both inhibitors. Based on the kinetic parameters determined here, it may be concluded that both recombinant elafin and trappin‐2 may act as potent anti‐inflammatory molecules and may be of therapeutic potential in the treatment of various inflammatory lung diseases.
Modulation of nitric oxide‐mediated metal release from metallothionein by the redox state of glutathione in vitro
Authors: Khatai Leila , Goessler Walter , Lorencova Helena , Zangger Klaus
Published: June 2004

Metallothioneins (MTs) release bound metals when exposed to nitric oxide. At inflammatory sites, both metallothionein and inducible nitric oxide synthase (iNOS) are induced by the same factors and the zinc released from metallothionein by NO suppresses both the induction and activity of iNOS. In a search for a possible modulatory mechanism of this coexpression of counteracting proteins, we investigated the role of the glutathione redox state in vitro because the oxidation state of thiols is involved in the metal binding in Cd‐S or Zn‐S clusters found in metallothioneins, and NO also binds to reduced glutathione via S‐nitrosation. Using a variety of techniques, we found that NO and also ONOO–‐mediated metal release from purified MTs is suppressed by reduced glutathione (GSH), but not by oxidized glutathione. Considering the millimolar concentrations of GSH present in mammalian cells, the metal release from MTs by NO should play no role in living systems. Therefore, the fact that it has been observed in vivo points to a hitherto unknown mechanism or additional compound(s) being involved in this physiologically relevant reaction and as long as this additional factor is not found experimental results on the MT–NO interaction should be treated with caution. Contrary to the peroxynitrite‐induced activation of guanylyl cyclase, where GSH is needed, we found that the metal release from metallothionein by peroxynitrite is not enhanced, but also suppressed by reduced glutathione. In addition, we show that zinc, the major natural metal ligand in mammalian MTs and suppressor of iNOS, is released more readily under the influence of NO than cadmium, but in contrast to the MT isoform 1, the amount of metal released from the β‐domain of MT‐2 is comparable to that from the α‐domain.
Chromatin dynamics at DNA replication, transcription and repair
Authors: Ehrenhofer‐Murray Ann E.
Published: June 2004

During DNA replication, transcription and DNA repair in eukaryotes, the cellular machineries performing these tasks need to gain access to the DNA that is packaged into chromatin in the nucleus. Chromatin is a dynamic structure that modulates the access of regulatory factors to the genetic material. A precise coordination and organization of events in opening and closing of the chromatin is crucial to ensure that the correct spatial and temporal epigenetic code is maintained within the eukaryotic genome. This review will summarize the current knowledge of how chromatin remodeling and histone modifying complexes cooperate to break and remake chromatin during nuclear processes on the DNA template.
Membrane distribution of epidermal growth factor receptors in cells expressing different gangliosides
Authors: Zurita Adolfo R. , Crespo Pilar M. , Koritschoner Nicolás P. , Daniotti José L.
Published: June 2004

Gangliosides have been found to reside in glycosphingolipid‐enriched microdomains (GEM) of the plasma membrane and to be involved in the regulation of epidermal growth factor receptor (EGFr or ErbB1) activity. To gain further insight into the mechanisms involved in EGFr modulation by gangliosides, we investigated the distribution of EGFr family members in the plasma membrane of CHO‐K1 cells, which were genetically modified to express different ganglioside molecules or depleted of glycolipids. Our data demonstrate that at least four different sets of endogenously expressed gangliosides, including GD3, did not have a significant effect on EGFr distribution in the plasma membrane. In addition, using confocal microscopy analysis we clearly demonstrated that the EGFr co‐localizes only to a minor extent with GD3. We also explored the endogenous expression, in wild‐type CHO‐K1 cells, of the orphan receptor ErbB2 (which is the preferred heteroassociation partner of all other ErbB proteins) and the effect of GD3 expression on its membrane distribution. Our results showed that CHO‐K1 cells endogenously express ErbB2 and that expression of the GD3 affected, to some extent, the membrane distribution of endogenous ErbB2. Finally, our findings support the notion that most EGFr are excluded from GEM, while an important fraction of ErbB2 is found to be associated with these microdomains in membranes from CHO‐K1 cells.
Expression of the pyrG gene determines the pool sizes of CTP and dCTP in Lactococcus lactis
Authors: Jørgensen Casper M. , Hammer Karin , Jensen Peter R. , Martinussen Jan
Published: June 2004

The pyrG gene from Lactococcus lactis encodes CTP synthase (EC 6.4.3.2), an enzyme converting UTP to CTP. A series of strains were constructed with different levels of pyrG expression by insertion of synthetic constitutive promoters with different strengths in front of pyrG. These strains expressed pyrG levels in a range from 3 to 665% relative to the wild‐type expression level. Decreasing the level of CTP synthase to 43% had no effect on the growth rate, showing that the capacity of CTP synthase in the cell is in excess in a wild‐type strain. We then studied how pyrG expression affected the intracellular pool sizes of nucleotides and the correlation between pyrG expression and nucleotide pool sizes was quantified using metabolic control analysis in terms of inherent control coefficients. At the wild‐type expression level, CTP synthase had full control of the CTP concentration with a concentration control coefficient close to one and a negative concentration control coefficient of −0.28 for the UTP concentration. Additionally, a concentration control coefficient of 0.49 was calculated for the dCTP concentration. Implications for the homeostasis of nucleotide pools are discussed.
The effect of HAMP domains on class IIIb adenylyl cyclases from Mycobacterium tuberculosis
Authors: Linder Jürgen U. , Hammer Arne , Schultz Joachim E.
Published: June 2004

The genes Rv1318c, Rv1319c, Rv1320c and Rv3645 of Mycobacterium tuberculosis are predicted to code for four out of 15 adenylyl cyclases in this pathogen. The proteins consist of a membrane anchor, a HAMP region and a class IIIb adenylyl cyclase catalytic domain. Expression and purification of the isolated catalytic domains yielded adenylyl cyclase activity for all four recombinant proteins. Expression of the HAMP region fused to the catalytic domain increased activity in Rv3645 21‐fold and slightly reduced activity in Rv1319c by 70%, demonstrating isoform‐specific effects of the HAMP domains. Point mutations were generated to remove predicted hydrophobic protein surfaces in the HAMP domains. The mutations further stimulated activity in Rv3645 eight‐fold, whereas the effect on Rv1319c was marginal. Thus HAMP domains can act directly as modulators of adenylyl cyclase activity. The modulatory properties of the HAMP domains were confirmed by swapping them between Rv1319c and Rv3645. The data indicate that in the mycobacterial adenylyl cyclases the HAMP domains do not display a uniform regulatory input but instead each form a distinct signaling unit with its adjoining catalytic domain.
Genomic organization, tissue distribution and deletion mutation of human pyridoxine 5′‐phosphate oxidase
Authors: Kang Jeong Han , Hong Mi‐Lim , Kim Dae Won , Park Jinseu , Kang Tae‐Cheon , Won Moo Ho , Baek Nam‐In , Moon Byung Jo , Choi Soo Young , Kwon Oh‐Shin
Published: June 2004

We used a combined computer and biochemical approach to characterize human pyridoxine 5′‐phosphate oxidase (PNPO). The humanPNPOgene is composed of seven exons and six introns, and spans approximately 8 kb. All exon/intron junctions contain the gt/ag consensus splicing site. The absence of TATA‐like sequences, the presence of Sp1‐binding sites and more importantly, the presence of CpG islands in the regulatory region of thePNPOgene are characteristic features of housekeeping genes. Northern blot analyses showed two species of poly(A)+RNA of ≈ 2.4 and ≈ 3.4 kb at identical intensity, whereas Western blot analysis showed that no protein isoform exists in any of the tissues examined. PCR‐based analysis led to the idea that two messages are transcribed from a single copy gene, and that the size difference is due to differential usage of the polyadenylation signal. The major sites ofPNPOexpression are liver, skeletal muscle and kidneys while a very weak signal was detected in lung. The mRNA master dot‐blot for multiple human tissues provided a complete map of the tissue distribution not only for PNPO but also for pyridoxal kinase and pyridoxal phosphatase. The data indicate that mRNA expression of all three enzymes essential for vitamin B6metabolism is ubiquitous but is highly regulated at the level of transcription in a tissue‐specific manner. In addition, human brain PNPO cDNA was expressed inEscherichia coli, and the roles of both the N‐ and C‐terminal regions were studied by creating sequential truncation mutants. Our results showed that deletion of the N‐terminal 56 residues affects neither the binding of coenzyme nor catalytic activity.
Amino acid biosynthesis and metabolic flux profiling of Pichia pastoris
Authors: Solà Aina , Maaheimo Hannu , Ylönen Katri , Ferrer Pau , Szyperski Thomas
Published: June 2004

Amino acid biosynthesis and central carbon metabolism of Pichia pastoris were studied using biosynthetically directed fractional 13C labeling. Cells were grown aerobically in a chemostat culture fed at two dilution rates (0.05 h−1, 0.16 h−1) with glycerol as the sole carbon source. For investigation of amino acid biosynthesis and comparison with glycerol cultivations, cells were also grown at 0.16 h−1 on glucose. Our results show that, firstly, amino acids are synthesized as in Saccharomyces cerevisiae. Secondly, biosynthesis of mitochondrial pyruvate via the malic enzyme is not registered for any of the three cultivations. Thirdly, transfer of oxaloacetate across the mitochondrial membrane appears bidirectional, with a smaller fraction of cytosolic oxaloacetate stemming from the mitochondrial pool at the higher dilution rate of 0.16 h−1 (for glucose or glycerol cultivation) when compared to the glycerol cultivation at 0.05 h−1. Fourthly, the fraction of anaplerotic synthesis of oxaloacetate increases from 33% to 48% when increasing the dilution rate for glycerol supply, while 38% is detected when glucose is fed. Finally, the cultivation on glucose also allowed qualitative comparison with the flux ratio profile previously published for Pichia stipitis and S. cerevisiae grown on glucose in a chemostat culture at a dilution rate of 0.1 h−1. This provided a first indication that regulation of central carbon metabolism in P. pastoris and S. cerevisiae might be more similar to each other than to P. stipitis.
Growth‐associated protein of 43 kDa (GAP‐43) is cleaved nonprocessively by the 20S proteasome
Authors: Denny John B.
Published: June 2004

Purified, nonubiquitinated growth‐associated protein of 43 kDa (GAP‐43) was attacked by purified reticulocyte 20S proteasome but not by the 26S proteasome. Cleavage yielded 12 N‐terminally labelled GAP‐43 fragments that could be resolved by SDS/PAGE. Inhibitor experiments suggested that proteasome β1 activity yielded the resolved bands and that proteasomeβ5 activity generated nonresolvable fragments. Processive degradation, yielding only nonresolvable fragments, therefore did not occur. Most of the resolved fragments co‐migrated with fragments formed in the reticulocyte lysate translation mixture used for GAP‐43 synthesis, which suggested that the fragments were also produced in the translation mixture by the endogenous reticulocyte lysate proteasome. Consistent with this idea, the addition of proteasome inhibitors to translation mixtures blocked fragment production. Ubiquitinated GAP‐43 appeared to be the source of the fragments in the presence of ATP, and nonubiquitinated GAP‐43 the source in the absence of ATP. The results therefore suggest that the lack of processing seen with the 20S proteasome is not an artefact arising from the way in which the 20S proteasome was purified. In one purification protocol, the GAP‐43 fragments formed in translation mixtures co‐purified with full‐length GAP‐43. These fragments were digested to nonresolvable products upon addition of purified 20S proteasome. Addition of calmodulin or G‐actin blocked the consumption of both full‐length GAP‐43 and the co‐purified GAP‐43 fragments. This showed that the resolved fragments can re‐enter the proteasome and be cleaved to nonresolvable products, indicating that the lack of processivity is not a result of their resistance to further proteasome attack. The difficult step therefore appears to be the transfer of the large fragments within the proteasome from the β1 to the β5 activity for further attack.
NMR solution structure of Cn12, a novel peptide from the Mexican scorpion Centruroides noxius with a typical β‐toxin sequence but with α‐like physiological activity
Authors: del Río‐Portilla Federico , Hernández‐Marín Elizabeth , Pimienta Genaro , Coronas Fredy V. , Zamudio Fernando Z. , Rodríguez de la Vega Ricardo C. , Wanke Enzo , Possani Lourival D.
Published: June 2004

Cn12 isolated from the venom of the scorpion Centruroides noxius has 67 amino‐acid residues, closely packed with four disulfide bridges. Its primary structure and disulfide bridges were determined. Cn12 is not lethal to mammals and arthropods in vivo at doses up to 100 μg per animal. Its 3D structure was determined by proton NMR using 850 distance constraints, 36 φ angles derived from 36 coupling constants obtained by two different methods, and 22 hydrogen bonds. The overall structure has a two and half turn α‐helix (residues 24–32), three strands of antiparallel β‐sheet (residues 2–4, 37–40 and 45–48), and a type II turn (residues 41–44). The amino‐acid sequence of Cn12 resembles the β scorpion toxin class, although patch‐clamp experiments showed the induction of supplementary slow inactivation of Na+ channels in F‐11 cells (mouse neuroblastoma N18TG‐2 × rat DRG2), which means that it behaves more like an α scorpion toxin. This behaviour prompted us to analyse Na+ channel binding sites using information from 112 Na+ channel gene clones available in the literature, focusing on the extracytoplasmic loops of the S5–S6 transmembrane segments of domain I and the S3–S4 segments of domain IV, sites considered to be responsible for binding α scorpion toxins.
Specific Localization of Macrophages in Pregnant Bovine Caruncles
Authors: Miyoshi M , Sawamukai Y
Published: June 2004

Contents

The objective of this study was to evaluate the distribution and phagocytotic function of macrophages in bovine caruncles during pregnancy. Pregnant Holstein caruncles obtained at a slaughterhouse and by Caesarean section just before the onset of parturition were used. Macrophages in these caruncles were observed immunohistochemically and histochemically. Macrophages were present in the parenchyma of caruncles throughout pregnancy. The macrophages were irregular in shape, and exhibited thin, long processes along the main and intermediate septa of caruncles. Macrophages increased as the gestation period progressed. Acid phosphatase activity of the macrophages appeared at 5–6 months of gestation and remained until the end of gestation period. In particular, macrophages showed strong acid phosphatase activity at the peripheral region of the caruncles just facing the chorionic villi. In addition, they were conglomerated in the hyperplastic prominences of caruncles. These results indicate that caruncle macrophages maintain the appropriate size and shape of each caruncle during pregnancy.
In vitro Capacitation and Acrosome Reaction of Dog Spermatozoa can be Feasibly Attained in a Defined Medium Without Glucose
Authors: Albarracín JL , Mogas T , Palomo MJ , Peña A , Rigau T , Rodríguez‐Gil JE
Published: June 2004

Contents

Incubation of dog spermatozoa in a medium without glucose and in the presence of lactate and pyruvate (l‐CCM) for 4 h at 38.5°C in a 5% CO2 atmosphere induced in vitro capacitation of these cells. This was verified after the combined specific capacitation‐like changes in percentages of viability and altered acrosomes, motility characteristics, sperm location of reactivity against Pisum sativum, Arachis hypogaea and Helix pomatia lectins and the tyrosine phosphorylation pattern. Furthermore, a feasible acrosome reaction (AR) was induced when spermatozoa incubated in l‐CCM for 4 h were further co‐incubated for 1 h with canine oocytes. This was demonstrated by AR‐like changes in percentages of viability, altered acrosomes, motility characteristics and sperm location of reactivity against P. sativum, A. hypogaea and H. pomatia lectins. All these results clearly indicate that in vitro capacitation, and subsequent AR, can be feasibly achieved without the presence of sugars. This ability can be related to the specific characteristics of energy‐metabolism regulation reported in dog spermatozoa.
Effect of Exogenous Progesterone on Post‐thaw Capacitation and Acrosome Reaction of Bovine Spermatozoa
Authors: Lukoseviciute K , Zilinskas H , Januskauskas A
Published: June 2004

Contents

The aim of this work was to study the effect of progesterone (P4) on capacitation and acrosome reaction (AR) of post‐thaw bovine spermatozoain vitro. Spermatozoa were incubated (0–180 min) in capacitation medium supplemented with 0, 0.1, 1.0 and 10.0 μg/ml of P4. At different time intervals aliquots were taken to determine sperm plasma membrane lipid destabilization, or capacitation (AR induced by lysophosphatidylcholine) in spermatozoa. The second experiment aimed to study the effects of P4, as potential inducer of AR in heparin‐capacitated spermatozoa. The acrosomal status and viability of spermatozoa were evaluated under an epifluorescence microscope using Ethidium homodimer/peanut agglutinin fluorescein isothiocyanate staining method. Plasma membrane scrambling in spermatozoa was assessed by a flow cytometer, using merocyanine staining. The results show that P4 at the concentrations used had no negative effects on sperm viability. Progesterone significantly enhanced sperm capacitation (p < 0.001), but had no effect on plasma membrane lipid stability (p > 0.05) and did not significantly increase the AR of heparin‐capacitated spermatozoa (p > 0.05). Progesterone displayed its effects in a dose‐dependent manner with a maximum effect of 10 μg/ml P4 at 180 min of incubation. The results demonstrate that in cryopreserved bovine semen, P4 acts as capacitating, but not as an AR‐inducing agent.
Influence of CRH and ACTH Administration on Endocrine Profile and Ovulation in Sows
Authors: Lang A , Kaeoket K , Kindahl H , Madej A , Einarsson S
Published: June 2004

Contents

Grouping of sows is a stressful event until the ranking is established. The purpose of this study was to simulate stress by repeated administration of porcine corticotropin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH)/tetracosactide and to study its influence on endocrine profile and ovulation. Four multiparous sows were used and blood was collected every 2 h from the onset of pro‐oestrus until 12 h after ovulation. The first oestrus after weaning was used to check ovulation and acclimatize the sows to their environment. The second oestrus after weaning was used as control. At their third oestrus CRH (0.6 μg/kg) and at their fourth oestrus ACTH (5 μg/kg) were given every 4 h from onset of oestrus until ovulation. The total ‘area under the curve’ of cortisol was twofold larger in two of four sows during the CRH treatment period, and two‐ to fourfold larger (p ≤ 0.05) during the ACTH treatment period, compared with the corresponding control period. In three sows, there was no clear effect of either CRH or ACTH on the levels of oestradiol 17β, luteinizing hormone (LH) or on the timing of ovulation. One sow was different in all hormonal patterns and also in the timing of ovulation. In all four sows, ACTH treatment lowered the baseline level of prostaglandin F2α‐metabolite. Therefore, we conclude that stage of the oestrous cycle seems to be of importance when investigating the influence of exogenous administration of CRH/ACTH on hormonal pattern and ovulation time in the sow.
Fanconi's syndrome and subsequent progressive renal failure caused by a Chinese herb containing aristolochic acid
Authors: LEE SANGHO , LEE TAEWON , LEE BYUNGCHEOL , CHOI HYUCKJAI , YANG MUNHO , IHM CHUN‐GYOO , KIM MYUNGJAE
Published: June 2004

SUMMARY:  Chinese herb nephropathy contains a variety of clinical features of progressive renal failure (indicated by studies conducted in Belgium) to the variant type of Fanconi's syndrome. Fanconi's syndrome has mostly been reported in Asian countries, and is characterized by proximal tubular dysfunction and slower progression to end‐stage renal disease (ESRD); it also often revealed a reversible clinical course. We describe a 43‐year‐old woman who presented with polyuria and polydipsia caused by Fanconi's syndrome. The cause of Fanconi's syndrome was not identified because the patient denied the intake of the Chinese herbal mixture at first. Fanconi's syndrome seemed to be reversible in its early stage, but it rapidly progressed to renal failure after 3 months, despite the interruption of Chinese mixture use. A renal biopsy revealed typical findings of aristolochic acid‐induced nephropathy. Aristolochic acids were also detected in the Chinese herbs that were consumed. This case highlights the variety of the clinical spectrum of aristolochic acid induced nephropathy (AAN). We emphasize that AAN should be suspected in all patients with Fanconi's syndrome, even if patients deny the intake of any Chinese herbal preparation.
α‐Smooth muscle actin immunoreactivity may change in nature in interlobular fibrosis of the pancreas in patients with congenital biliary dilatation
Authors: Matsubara Kenro , Suda Koichi , Suzuki Fujihiko , Kumasaka Toshio , Shiotsu Hidetoshi , Miyano Takeshi
Published: June 2004

Pancreatic fibrosis in patients with congenital biliary dilatation (CBD) or choledochal cyst was studied to determine why biliary pancreatitis seldom progresses to chronic pancreatitis/more progressive state. Pancreatic collagenization in eight patients (three adults with pancreatoduodenectomy and five children with biopsy of the pancreas performed when excising the cyst) with CBD was evaluated histopathologically and immunohistochemically. Interlobular and periductal fibrosis with both collagen Type I and Type III immunoreactivities was found in six out of eight cases and in all four cases in which the pancreatic duct was included, respectively. The interlobular area was seldom immunoreactive for α‐smooth muscle actin (α‐SMA), a marker for myofibroblasts, but was usually positive for CD34, a human progenitor cell antigen. In contrast, the periductal area was usually immunoreactive for α‐SMA, but usually negative for CD34 and immunopositive for bcl‐2, indicating a continuously progressive state of fibrosis, in which ‘pre‐existing’α‐SMA immunoreactivity in the interlobular area may change in nature and lead to CD34‐positive fibrosis or apoptosis. In conclusion, biliary pancreatitis is not likely to evolve into chronic pancreatitis/more progressive state because ‘pre‐existing’α‐SMA immunoreactivity in the interlobular area may change in nature.
The metacommunity concept: a framework for multi‐scale community ecology
Authors: Leibold M. A. , Holyoak M. , Mouquet N. , Amarasekare P. , Chase J. M. , Hoopes M. F. , Holt R. D. , Shurin J. B. , Law R. , Tilman D. , Loreau M. , Gonzalez A.
Published: June 2004

The metacommunity concept is an important way to think about linkages between different spatial scales in ecology. Here we review current understanding about this concept. We first investigate issues related to its definition as a set of local communities that are linked by dispersal of multiple potentially interacting species. We then identify four paradigms for metacommunities: the patch‐dynamic view, the species‐sorting view, the mass effects view and the neutral view, that each emphasizes different processes of potential importance in metacommunities. These have somewhat distinct intellectual histories and we discuss elements related to their potential future synthesis. We then use this framework to discuss why the concept is useful in modifying existing ecological thinking and illustrate this with a number of both theoretical and empirical examples. As ecologists strive to understand increasingly complex mechanisms and strive to work across multiple scales of spatio‐temporal organization, concepts like the metacommunity can provide important insights that frequently contrast with those that would be obtained with more conventional approaches based on local communities alone.
Energetic determinants of abundance in winter landbird communities
Authors: Meehan Timothy D. , Jetz Walter , Brown James H.
Published: June 2004

There is increasing evidence that individual energetics constrain macroecological patterns. Here we model total abundance within winter landbird communities as a function of (1) energy supply, as measured by ecosystem net primary productivity, and (2) energy use of individuals, as influenced by body mass and ambient temperature. Using data from the North American Christmas Bird Count, we find that total abundance increases with productivity to the 0.61 power, and decreases with body mass and environmental temperature as predicted by metabolic theory when individuals are below their thermoneutral zone. We note a negative relationship between ambient temperature and average body mass, and suggest that this community‐level pattern, reminiscent of Bergmann's Rule, is related to a tendency for small species to be less‐abundant or absent from cold locations. Results from this study emphasize the importance of individual‐level metabolism for understanding large‐scale ecological patterns.
Complex structural effects of two hemispheric climatic oscillators on the regional spatio‐temporal expansion of a threatened bird
Authors: Almaraz Pablo , Amat Juan A.
Published: June 2004

Links between climatic conditions in the eastern equatorial Pacific and extratropical ecological processes remain unexplored. The analysis of a 20‐year time series of spatial and numeric dynamics of a threatened Mediterranean bird suggests, however, that such couplings can be remarkably complex. By providing a new ecological time‐series modelling approach, we were able to dissect the joint effects of the El Niño/Southern Oscillation (ENSO), the North Atlantic Oscillation (NAO), regional weather, population density and stochastic variability on the expansion dynamics of the White‐headed duck (Oxyura leococephala) in Spain. Our results suggest that the spatial and numeric dynamics of ducks between peak brood emergence and wintering were simultaneously affected by different climatic phenomena during different phases of their global cycles, involving time lags in the numeric dynamics. Strikingly, our results point to both the NAO and the ENSO as potentially major factors simultaneously forcing ecological processes in the Northern Hemisphere, and suggest a new pathway for non‐additive effects of climate in ecology.
Polylysogeny and prophage induction by secondary infection in Vibrio cholerae
Authors: Espeland Eric M. , Lipp Erin K. , Huq Anwar , Colwell Rita R.
Published: June 2004

Strains of Vibrio cholerae O1, biotypes El Tor and classical, were infected with a known temperate phage (ΦP15) and monitored over a 15‐day period for prophage induction. Over the course of the experiment two morphologically and three genomically distinct virus‐like particles were observed from the phage‐infected El Tor strain by transmission electron microscopy and field inversion gel electrophoresis, respectively, whereas only one phage, ΦP15, was observed from the infected classical strain. In the uninfected El Tor culture one prophage was spontaneously induced after 6 days. No induction in either strain was observed after treatment with mitomycin C. Data indicate that El Tor biotypes of V. cholerae may be polylysogenic and that secondary infection can promote multiple prophage induction. These traits may be important in the transfer of genetic material among V. cholerae by providing an environmentally relevant route for multiple prophage propagation and transmission.
Mini‐Tn7 transposons for site‐specific tagging of bacteria with fluorescent proteins
Authors: Lambertsen Lotte , Sternberg Claus , Molin Søren
Published: June 2004

The mini‐Tn7 transposon system is a convenient tool for site‐specific tagging of bacteria in which the tagging DNA is inserted at a unique and neutral chromosomal site. We have expanded the panel of mini‐Tn7 delivery plasmids expressing different fluorescent proteins (stable and unstable) from the Escherichia coli lac derived promoter, PA1/04/03, or from the growth‐rate‐dependent Escherichia coli promoter PrrnB P1. The mini‐Tn7 transposons were inserted and tested in the soil bacterium, Pseudomonas putida KT2440. Successful and site‐specific tagging was verified by Southern blots as well as by PCR. Furthermore, the effect of fluorescent protein expression on the cellular growth rate was tested by growth competition assays.
Top‐down impact of bacterivorous nematodes on the bacterial community structure: a microcosm study
Authors: De Mesel Ilse , Derycke Sofie , Moens Tom , Van der Gucht Katleen , Vincx Magda , Swings Jean
Published: June 2004

The influence of bacterivorous nematodes (Diplolaimelloides meyli, Diplolaimelloides oschei, Diplolaimella dievengatensis, Panagrolaimus paetzoldi) on the development of a bacterial community growing on decaying cordgrass detritus was studied in laboratory microcosm experiments. Cordgrass leaves were incubated on a sediment surface with a natural bacterial mixture containing bacteria from sediment, cordgrass detritus and habitat water. The four nematode species were applied separately to the microcosms; controls remained without nematodes. Samples were taken seven times over a 65‐day period. The bacterial community structure was analysed by means of DGGE of the 16S rRNA genes. Multi Dimensional Scaling showed grouping of the samples per treatment. Analysis of Similarities indicated that the differences between treatments were significantly larger than differences within treatments. Our results suggest that nematodes can have a significant structuring top‐down influence on the ‘pool’ of bacteria growing on the detritus, even at low densities. Dissimilarities were similar between all treatments. Differences in bacterial community composition within the treatments with monhysterids (D. meyli, D. oschei and D. dievengatensis) can be explained by species‐specific food preferences.Panagrolaimus paetzoldion the other hand feeds unselectively, and thus affects the bacterial community differently. A top‐down effect of the nematodes on the diversity of the bacterial community was only evident under high grazing pressure, i.e. in the presence ofP. paetzoldi.
Bacterial diversity in deep Mediterranean sediments: relationship with the active bacterial fraction and substrate availability
Authors: Luna G. M. , Dell’Anno A. , Giuliano L. , Danovaro R.
Published: June 2004

We investigated vertical distribution and depth‐related patterns (from 670 to 2570 metres) of bacterial diversity in sediment samples collected along a transect in the warm deep Mediterranean sea. Analyses of bacterial diversity were compared with the abundance of benthic bacteria, their metabolically active fraction and the substrates potentially available for their growth. The number of active bacteria was dependent upon the availability of organic substrate in the sediment deriving from phytopigment inputs from the photic layer. The T‐RFLP analysis revealed that the surface layers of all sediments analysed were dominated by the same ribotypes, but clear shifts in bacterial community structure were observed in deeper sediment layers. High values of bacterial diversity (expressed as D, H’) and evenness (as J) were observed at all stations (a total of 61 ribotypes was identified), and as a result of the large fraction of rare ribotypes (c. 35%), the overall bacterial diversity in the deep sea region investigated was among the highest reported so far in literature. Biodiversity parameters did not display any relationship with water depth, but ribotype richness was related with the number and percentage of active bacteria, suggesting a coupling between organic inputs stimulating bacterial growth and deep‐sea bacterial diversity.
Corporate Lobbying on Accounting Standards: Methods, Timing and Perceived Effectiveness
Authors: Georgiou George
Published: June 2004

There is a long‐standing concern in the literature about the potential importance of non‐observable forms of lobbying that may be used by corporate managers to influence accounting standard setting bodies. To date, however, no study has documented their nature or their volume. This study provides such evidence in the context of the U.K.'s Accounting Standards Board (ASB) standard setting process for the period 1991–96. It also provides evidence with respect to the timing at which lobbying activity takes place and its perceived effectiveness by corporate managers. The findings suggest that companies use a variety of lobbying methods, including appeals to their auditors and private meetings with ASB members and staff. Importantly, however, the use of these methods is significantly associated with the use of comment letters; companies which submit comment letters are much more likely to use other methods than companies which do not. Other findings suggest that more companies lobby during the stages of the ASB process at which public consultation takes place (e.g., exposure period of a discussion paper) than at the earlier stages of the process (e.g., agenda formation) which are considered in the literature as the stages at which lobbying can be most effective. With respect to the perceived effectiveness of lobbying, companies which lobbied the ASB considered lobbying to be more effective than companies which did not.
Shifting International Competitiveness: An Analysis of Market Share in Manufacturing Industries in Japan, Korea, Taiwan and the USA*
Authors: James William E. , Movshuk Oleksandr
Published: June 2004

In the present study we conduct constant market share analysis of the imports and apparent consumption of the manufacturing industries of four major economies‐Korea, Japan, Taiwan and the USA. Additionally, the current study disaggregates import penetration in manufacturing, including sectors with relatively high technological requirements. Statistical tests of the significance of changes in import penetration in manufacturing industries are also conducted. The real growth of exports and apparent consumption in the two largest OECD markets is decomposed into: (i) the commodity composition effect; and (ii) the competitiveness effect. Finally, we examine the significance of trade policy for changes in import penetration in Japan and the USA.
Wage Reforms in China During the 1990s
Authors: Yueh Linda Y.
Published: June 2004

In urban areas of China, economic reforms were intensely implemented after 1984. We focus on two primary aspects of the reforms in the 1990s, those pertaining to the labor market and to wages. Based on original interviews and two unique household data sets, we investigate the effects of the reforms. Our first finding is that the components of annual income have changed, reflecting fewer subsidies and more diverse sources of income (such as self‐employment), over the period from 1995 to 1999. By 1999, the wage structure reflects less seniority‐based pay, allows for more discretion in rewarding non‐productive characteristics (gender and Communist Party membership, for example) and also permits more productivity‐related pay (as evidenced by increased returns to human capital).
Price Common Volatility or Volume Common Volatility? Evidence from Taiwan's Exchange Rate and Stock Markets
Authors: Chen Shyh‐Wei , Shen Chung‐Hua
Published: June 2004

This paper investigates the common volatility structure of stock and exchange rate markets of Taiwan. The two markets are often linked together and we are interested in knowing whether price or volume is a good proxy to pursue this issue. We claim that Taiwanese government interventions distort the timing of conventional price volatility clustering in the two markets. The unrestricted trading volumes reveal more information regarding the market than price. We find that common volatility does exist in the stock and exchange markets and this fact is uncovered more easily by using trading volume than by using prices.