bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamical constraints and nuclear spin caused restrictions in collision systems
Authors: Gerlich D , Windisch F , Hlavenka P , Plašil R , Glosik J
Published: September 2006

This contribution summarizes a variety of results and ongoing activities, which contribute to our understanding of inelastic and reactive collisions involving hydrogen ions. In an overview of our present theoretical knowledge of various

collision systems (
m
+
n
≤5), it is emphasized that although the required potential energy surfaces are well characterized, no detailed treatments of the collision dynamics are available to date, especially at the low energies required for astrochemistry. Instead of treating state-to-state dynamics with state of the art methods, predictions are still based on: (i) simple thermodynamical arguments, (ii) crude reaction models such as H atom exchange or proton jump, or (iii) statistical considerations used for describing processes proceeding via long-lived or strongly interacting collision complexes. A central problem is to properly account for the consequences of the fact that H and D are fermions and bosons, respectively.

In the experimental and results sections, it is emphasized that although a variety of innovative techniques are available and have been used for measuring rate coefficients, cross-sections or state-to-state transition probabilities, the definitive experiments are still pending. In the centre of this contribution are our activities on various
m
+
n
=5 systems. We report a few selected additional results for collisions of hydrogen ions with
p
-H
2
,
o
-H
2
, HD, D
2
or well-defined mixtures of these neutrals. Most of the recent experiments are based on temperature variable multipole ion traps and their combination with pulsed gas inlets, molecular beams, laser probing or electron beams. Based on the state-specific model calculations, it is concluded that for completely understanding the gas phase formation and destruction of

in a trap, an
in situ
characterization of all the experimental parameters is required with unprecedented accuracy. Finally, the need to understand the hydrogen chemistry relevant for dense pre-stellar cores is discussed.
Models of in warm, diffuse, molecular gas in the Galactic centre
Authors: Le Petit Franck , Roueff Evelyne
Published: September 2006

Oka
et al
. (Oka
et al
. 2005
Astrophys. J
.
632
, 882–893) have recently observed a large column density of

in the Galactic centre. In one of the gaseous components, a column density of

in its metastable level (3,3) of approximately 4×10
14
 cm
−2
is measured. From the excitation of

, they deduce a density below 50 cm
−3
and a temperature approximately 270 K. In this paper, we report results for this region from a new version of our PDR code which includes the

excitation. Models show it is unlikely that the mean temperature of the gas could be above 100 K. We also show that there is a possibility to produce hot

in C-shocks.
Deuterated as a probe of isotope fractionation in star-forming regions
Authors: Roberts Helen , Millar T.J
Published: September 2006

Observations of molecular D/H ratios in the interstellar medium are used to probe the physical conditions, such as temperature, ionization fraction and the importance of gas–grain reactions.

In cold, dense regions, such as cores which are collapsing to form stars, the level of deuterium fractionation depends on the conversion of

into its deuterated isotopologues (H
2
D
+
, D
2
H
+
and

). The relative abundances of these molecules uniquely probe the centres of these cores where other, heavier, species have frozen onto dust grains.

We present models of the deuterium chemistry close to the centre of a pre-stellar core, in the last stage before the star forms, showing the dependence of the observable molecular D/H ratios on the physical parameters and rate coefficients that are assumed. We compare model predictions with the latest observations of these regions.
Deuterium enhancement in in pre-stellar cores
Authors: Vastel Charlotte , Phillips T.G , Caselli P , Ceccarelli C , Pagani L
Published: September 2006

Deuterium enhancement of monodeuterated species has been recognized for more than 30 years as a result of chemical fractionation that results from the difference in zero-point energies of deuterated and hydrogenated molecules. The key reaction is the deuteron exchange in the reaction between HD, the reservoir of deuterium in dark interstellar clouds, and the

molecular ion, leading to the production of H
2
D
+
molecule, and the low temperature in dark interstellar clouds favours this production. Furthermore, the presence of multiply deuterated species have incited our group to proceed further and consider the subsequent reaction of H
2
D
+
with HD, leading to D
2
H
+
, which can further react with HD to produce

. In pre-stellar cores, where CO was found to be depleted, this production should be increased as CO would normally destroy

. The first model including D
2
H
+
and

predicted that these molecules should be as abundant as H
2
D
+
. The first detection of the D
2
H
+
was made possible by the recent laboratory measurement for the frequency of the fundamental line of
para
-D
2
H
+
. Here, we present observations of H
2
D
+
and D
2
H
+
towards a sample of dark clouds and pre-stellar cores and show how the distribution of
ortho
-H
2
D
+
(1
1,0
–1
1,1
) can trace the deuterium factory in pre-stellar cores. We also present how future instrumentation will improve our knowledge concerning the deuterium enhancement of

.
in the electronic triplet state: current status
Authors: Alijah Alexander , Varandas António J.C
Published: September 2006

We review the theoretical work carried out on the tri-hydrogen ion in the electronic triplet state 1
3
E
′, which is split into
a

and 2
3
A
′ by vibronic interaction. We begin with an overview on analytical potential energy surfaces and calculations of rovibrational states by focusing on our own results, which are based on the most accurate potential energy surfaces available so far. This is followed by an examination of the selection rules and predictions of infrared transition frequencies. Finally, we discuss the Slonczewski resonance states supported by the upper sheet of the potential energy surface. Theoretical work reported here may be of interest for future experiments on the title ion.
Ion-pair formation in electron recombination with H
3
+
Authors: Larson Åsa , Roos Johanna , Orel Ann E
Published: September 2006

The process of resonant ion-pair formation following electron collisions with

is studied. The relevant diabatic potential energy surfaces and the electronic couplings between these surfaces are calculated. The reaction is then described using a time-dependent approach with wave packets propagating on the coupled potentials. In order to describe the reaction, it is found necessary to include at least two dimensions in the model. The effects of the Rydberg states on the cross-section for this process are discussed.
The role of asymptotic vibrational states in
Authors: Tennyson Jonathan , Barletta Paolo , Munro James J , Silva Bruno C
Published: September 2006

Calculations are discussed which characterize all the vibrational bound states of the

and D
2
H
+
molecular ions using a realistic
ab initio
potential energy surface. Graphical analysis and calculation of rotational constants show that both ions support a series of atom–diatom-like long-range states: asymptotic vibrational states. The role of these states in the

system and other molecules is discussed. The vibrational calculations are extended above dissociation where the resulting (Feshbach) resonances are shown to be too short-lived to be of importance for the

photodissociation spectrum.
The biological and physical stability and resilience of a selection of Scottish soils to stresses
Authors: Kuan H. L. , Hallett P. D. , Griffiths B. S. , Gregory A. S. , Watts C. W. , Whitmore A. P.
Published: September 2006

The ability of soil to resist and recover from anthropogenic and environmental stresses defines stability and resilience, respectively; an understanding of this ability is critical to sustainable land‐use. In this study of 26 soils from across Scotland, we examine the influence of soil properties and antecedent conditions on physical and biological resilience to stress. The sites studied covered a wide range of soil types and land management, including serpentine soil from the Shetland Islands, a catena on the Highland Boundary Fault, and young aeolian sandy soils on the east coast. Biological resilience was measured as CO2 evolution from soil with added plant residues after either a transient (heat) or a persistent (copper) stress. Measures of physical resilience were: (i) compression and expansion indices following rapid uniaxial compression (to 50 kPa) and relaxation; and (ii) void ratio changes due to an overburden stress and subsequent cycles of wetting and drying. Evolution of CO2 from soil with added plant residues after heat or copper stress ranged from 23% to >100% that of the unperturbed soil, while the air‐filled void ratio after the overburden stress ranged from 70% to >100% that of the unperturbed soil. Soils were grouped into quartiles based on their resistance to and recovery after each of the four prescribed stresses. Soil organic carbon (SOC) content correlated strongly with resilience after biological and physical stresses, particularly resistance to Cu stress (r= 0.72) and recovery from compression (r= 0.67), whereas there were no strong correlations between resilience following heat and any of the measured soil characteristics, although both land use and soil class were helpful in separating the responses. Resistance to compression was negatively correlated with SOC (r=−0.63).
Effects of artificial ultraviolet‐B radiation on growth and fatty acid composition of duckweed (Lemna minor)
Authors: YOUNG D. L. W. , WIEGAND M. D. , LOADMAN N. L. , COLLINS S. A. , BALLEVONA A. J. , HUEBNER J. D.
Published: September 2006

1. Duckweed (Lemna minor), collected either in summer or early fall was exposed under laboratory conditions to control (photosynthetically active and UV‐A radiation) or experimental (control plus UV‐B radiation) conditions.

2. Growth and survival were determined by counting the number of green, and brown/white fronds following 1–5 or 11 days of irradiation. Growth of duckweed was impaired by exposure to UV‐B radiation in the fall experiment but not in the summer.

3. Fatty acid compositions were analysed following 5 or 11 days of irradiation and a recovery period of 0, 5, 29 or 40 h. Concentrations of the major fatty acids, palmitic, linoleic (LA) and α‐linolenic (ALA) acids were similar in the summer and fall duckweed collections, but the summer samples had higher concentrations of the desaturation products of LA and ALA.

4. UV‐B exposure had small, but significant, and contrasting effects on duckweed fatty acid concentrations. In the summer experiment, duckweed exposed to UV‐B had slightly lower concentrations of major fatty acids than control duckweed, while the reverse was true in the fall experiments.

5. These minor effects of UV‐B on concentrations of LA and ALA would be unlikely to have a major impact on the supply of these essential fatty acids from duckweed to freshwater food webs.
Carbon pathways to zooplankton: insights from the combined use of stable isotope and fatty acid biomarkers
Authors: PERGA MARIE‐ELODIE , KAINZ MARTIN , MATTHEWS BLAKE , MAZUMDER ASIT
Published: September 2006

1. Numerous studies have quantified the relative contribution of terrestrial‐ and phytoplankton‐derived carbon sources to zooplankton secondary production in lakes. However, few investigated the pathways along which allochthonous and autochthonous carbon (C) was actually conveyed to consumers.

2. We suggest that the combined use of fatty acid and stable isotope biomarkers could solve this issue. We conducted a field study on two oligotrophic lakes, in which primary production increased significantly between 2002 and 2004. We used modelling to estimate the contribution of terrestrial‐ and phytoplankton‐derived C to particulate organic C (POC) and zooplankton production from their δ13C values in 2002 and 2004.

3. According to the isotope model, phytoplankton‐derived C accounted for a major part of the POC pool in both lakes and supported more Daphnia sp. production in 2004 than in 2002. Fatty acid data revealed that increased contribution of algal‐C to Daphnia production, although common between both lakes, was achieved through C pathways that were different. In one lake, Daphnia grazed more intensively on phytoplankton, whereas in the other there was greater grazing on bacteria. In the latter case, the increased primary production resulted in greater release of algal‐derived dissolved organic C (DOC), which may have supported extra bacterial and eventually Daphnia, production.

4. This is the first study illustrating that the combination of fatty acid and stable isotope biomarkers could further our understanding of the factors controlling the relative magnitude of food webs pathways conveying organic matter to zooplankton.
End of the line? Tramtrack and cell fate determination in Drosophila
Authors: Badenhorst Paul , Harrison Stephen , Travers Andrew
Published: September 2006

Cell differentiation reflects the balance of two opposing influences, pathways which confer specialized properties on specific cells or groups of cells, and antagonising mechanisms which modulate responsiveness to such differentiative cues. It appears that the zinc finger protein Tramtrack (Ttk) fulfils the latter function in the CNS and PNS of Drosophila. Ttk seems to be able to inhibit neural development by down‐regulating competence to respond to neuralising signals. We speculate, however, that restriction of neural competence is merely one example of a more general ability of Ttk to influence differentiation and that, given its widespread expression profile, Ttk might be implicated in a number of differentiative events.
Analysis of the cell cycle in the budding yeast Candida albicans by positioning of chromosomes by fluorescence in situ hybridization (FISH) with repetitive sequences
Authors: Chibana Hiroji , Tanaka Kenji , Yanagida Mitsuhiro
Published: September 2006

In the budding yeasts, including Saccharomyces cerevisiae, in which individual chromosomes cannot be visualized by microscopy, the mitotic phases in the cell cycle have not been correlated with the chromosome behaviour. We used various repetitive sequences, namely, rDNA, telomeric sequences and RPSs, which are localized in limited regions in almost all chromosomes, as probes for fluorescence in situ hybridization (FISH) to analyse the cell cycle phases in a pathogenic yeast Candida albicans. The positioning of the FISH signals was analysed quantitatively in relation to the length of spindle microtubules in the nuclear domain.

Results: RPSs were randomly distributed in the interphase nucleus, and they formed aggregates with the development of the spindle. DNA synthesis was complete before RPSs came closest to the spindle. As the spindle elongated, they were scattered along the spindle and then separated into two clusters at the spindle poles at the end of anaphase. rDNA was localized in the nucleolar domain, and telomere signals were randomly distributed throughout mitosis.

Conclusion: By estimating quantitatively the proportions of mitotic cells with particular configurations of both microtubules and chromosomes in a population of rapidly proliferating cells, we were able to define various stages in the progression of mitosis. The S phase and pro‐to‐prometaphase were overlapping and the G2 phase was lacking. Unexpectedly, the pole‐to‐pole elongation of the spindle (anaphase B) was predominating and was followed by movement of chromosomes to the poles (anaphase A).
Inhibition of agrin‐mediated acetylcholine receptor clustering by utrophin C‐terminal peptides
Authors: Namba Tsunehisa , Scheller Richard H. , Hirokawa Nobutaka
Published: September 2006

Background: Agrin is an extracellular matrix protein that is required for neuromuscular synaptogenesis and is particularly important in the clustering of acetylcholine receptors at post‐synaptic sites. Little is known about the signal transduction pathway of agrin‐mediated receptor clustering, although cytoskeletal elements and a dystrophin associated glycoprotein complex (DGC) have been implicated. Because agrin binds to α‐dystroglycan, a member of the DGC, and the DGC is linked to actin through utrophin at postsynaptic sites, it has been suggested that binding of utrophin to the DGC plays a central role in agrin mediated receptor clustering.

Results: To test this hypothesis, we expressed at high levels the DGC binding domains of utrophin in cultured myotubes using recombinant Semliki Forest Virus. Myotubes expressing the utrophin and dystrophin DGC binding domain formed significantly fewer acetylcholine receptor clusters in response to agrin than myotubes expressing other proteins.

Conclusions: These results suggest involvement of the DGC and utrophin in the signal transduction pathway of agrin‐mediated acetylcholine receptor cluster formation or stabilization.
Proteinase inhibitors and helminth parasite infection
Authors: KNOX D. P.
Published: September 2006

The concept that parasites may utilize proteinase inhibitors to survive within the host has been with us for 100 years. Given that we now know that proteinases are involved in key areas of the host anti‐parasite immune response including antigen presentation, effector cell function and tissue dissolution and remodelling, it is somewhat surprising that the proteinase inhibitors of parasite origin have not generally been the subject of intense research effort. There is now substantial evidence to show that nematode parasites utilize these inhibitors to protect themselves from degradation by host proteinases, to facilitate feeding and to manipulate the host response to the parasite. The diversity of the parasite‐derived inhibitors is also being revealed and they target the four major proteinase classes, namely serine, cysteine, aspartic and metallo‐proteinases. This review summarizes the information available on nematode‐derived proteinase inhibitors and what is known of their putative functions. Their potential as targets for immunological control is also addressed.
Wolbachia surface protein (WSP) inhibits apoptosis in human neutrophils
Authors: BAZZOCCHI C. , COMAZZI S. , SANTONI R. , BANDI C. , GENCHI C. , MORTARINO M.
Published: September 2006

Polymorphonuclear cells (PMNs) are essential for the innate immune response against invading bacteria. At the same time, modulation of PMNs’ apoptosis or cell death by bacteria has emerged as a mechanism of pathogenesis. Wolbachia bacteria are Gram‐negative endosymbionts of filarial nematodes and arthropods, phylogenetically related to the genera Anaplasma, Ehrlichia and Neorickettsia (family Anaplasmataceae). Although several pathogens are known to interfere with apoptosis, there is only limited information on specific proteins that modulate this phenomenon. This is the first evidence for the anti‐apoptotic activity of a surface protein of Wolbachia from filarial nematode parasites (the Wolbachia surface protein, WSP). The inhibition of apoptosis was demonstrated on purified human PMNs in vitro by different methods. TUNEL assay showed that the percentage of dead cells was reduced after stimulation with WSP; Annexin V‐FITC binding assay confirmed that cell death was due mainly to apoptosis and not to necrosis. Reduced caspase‐3 activity in stimulated cells also confirmed an inhibition of the apoptotic process.
The Protective Effect against E. coli of O and K Antibodies of Different Immunoglobulin Classes
Authors: KAIJSER B. , HOLMGREN J. , HANSON L. A.
Published: September 2006

The protective effect of antiserum to E. coli bacteria was studied in intraperitoneally infected mice. It was found that protection was obtained with O and K antibodies. There was no indication that H antibodies could prevent infection. 19S (IgM) and 78 (IgG) antibodies showed about the same protection against infection.
Use of Lightly Haptenated Phage to Detect High‐Affinity Antibody
Authors: KOSKIMIES SAIJA , MÄKELÄ O. , SEPPÄLÄ I. J. T.
Published: September 2006

We coupled bacteriophage T4 with standard (0.16%) or low (0.005%) concentrations of NIP‐azide. The low concentration produced haptenated phage (type B) that was inactivated by the IgG anti‐NIP of some rabbits but not by that of other rabbits similarly immunized. The most active IgG fraction at an anti‐NIP concentration of 100 μg/ml inactivated the type B phage with a titre of 2400, while the same anti‐NIP concentration of the least active IgG fraction from another rabbit had a titre of 0.3. With the standard haptenated phage titres only varied within a 20‐fold range. IgM fractions of a few rabbits tested did not appear to exhibit a great variation with the type B phage. The IgG fractions with high titres against the type B phage bound more NIP‐hapten at low (∼ 10−10 M) hapten concentrations than those with a low titre, but this superiority was greatly reduced by an increase of hapten concentration to 10−8 M. The same phenomenon could be demonstrated by an inhibition technique, lnactivation of type B phage appeared to detect exclusively antibodies with association constants considerably higher than 108. Its affinity threshold seems to be higher than the threshold of two other methods employed, haemagglutination of haptenated erythrocytes and inactivation of the standard haptenated phage.
Antigenic and Immunological Characteristics of Tryptic and Chymotryptic Subfragments from the Cγ3 Homology Region of Human Immunoglobulin G
Authors: TURNER M. W. , KOMVOPOULOS ATHENA , BENNICH H. , NATVIG J. B.
Published: September 2006

Subfragments of the pFc fragment (equivalent to the Cγ3 homology region) of human IgG have been obtained by tryptic and chymotryptic digestion. Tryptic digestion for 4 or 8 hours removed N‐terminal peptides of 5 and 7 amino acid residues respectively. Chymotryptic digestion appeared to remove an N‐terminal pentapeptide and also approximately 14 residues from the C‐terminus. However, chymotryptic cleavage in the presence of trypsin inhibi tor removed the C‐terminal peptide and only 2 N‐terminal residues. Haemag‐glutination‐inhibition tests for Gm activity indicated that both of the tryptic fragments retained Gm(a), (x), (b°), and ‘non a’ activities. In contrast, the chymotryptic fragments lacked Gm(a), (x), and ‘non a’ activities, but retained Gm (b°) activity. These results support our earlier hypothesis that certain C‐terminal amino acids of the 7‐chain are essential for the serological expres sion of Gm(a) and ‘non a’ markers.
Formation of Hybrid IgM Subunits
Authors: HARBOE M. , SOLHEIM B. G.
Published: September 2006

A mixture of rabbit IgM anti‐human A1 red cell antibody and a human 125I‐labelled monoclonal IgM was reduced with mercaptoethanot and exposed to oxygen under conditions in which most of the half subunits coalesced to IgM subunits with reformation of interchain disulphide bonds. Hybrid molecules were demonstrated in the mixture by precipitin tests with autoradiography and by binding of 125l to human A1 red cells. By careful selection of IgM antibodies with high energy in each binding site, such hybrids may be useful ‘IgM coats’ for haemagglutination inhibition tests attempting to define sub‐class‐specific and genetically determined antigens on IgM.
When Allogeneic Mouse Spleen Cells Are Mixed in Vitro the T‐Cells Secrete a Product Which Guides the Maturation of B‐Cells
Authors: BRITTON S.
Published: September 2006

Allogeneic mouse spleen cells of strong hlstocompatibility difference mixed in vitro at equal proportions are unable to make a primary antibody response against thymus‐dependent as well as thymus‐independent antigens. This non‐responsiveness is not due to mutual cytotoxicity, because the reactivity of the cell partners can be recovered if the mixtures are transferred to irradiated hosts isoimmune to one of the cell partners. Responsiveness of allogeneic cell mixtures depends on the proportions at which the allogeneic cells are mixed, the strength of histocompatibility differences, the functional state of the ad mixed cells, the timing of the admixture, and the T/B cell ratio of the ad mixed cells. Supernatants from cultured allogeneic spleen cell mixtures can restore responsiveness of otherwise non‐responsive B‐spleen cells. The results suggest that interaction between cultured allogeneic T‐cells leads to rapid formation of soluble material which, depending on concentration, can either initiate or inhibit the maturation of B‐cells into antibody‐secreting cells in the presence of specific antigen.
Lymphocyte Populations and Cellular Immune Reactions in Juvenile Rheumatoid Arthritis
Authors: HØYERAAL H. M. , FRØLAND S. S. , WISLØFF F.
Published: September 2006

Ten patients with juvenile rheumatoid arthritis and age‐ and sex‐matched healthy controls were investigated in pairs. The patients were found to have both normal proportions and normal absolute numbers of T lymphocytes, B lymphocytes, and the Fc‐receptor‐bearing lymphoid cells in peripheral blood. No abnormality of mitogen‐induced lymphocyte transformation was observed. Lymphocyte‐mediated cytotoxicity induced by phytohemagglutinin (PHA) or anti‐target cell antibodies was also found to be normal. As in an earlier study, impaired delayed hyper‐sensitivity by skin testing was observed in the patient group, thus indicating a dissociation between in vivo and in vitro parameters of lymphoid cell function.
Antibodies Against Nicotinic Acetylcholine Receptor and Skeletal Muscle in Human and Experimental Myasthenia Gravis
Authors: AARLI J. A. , MATTSSON C. , HEILBRONN E.
Published: September 2006

Using rocket immunoelectrophoresis and indirect haemagglutination tests, antibodies to nicotinic acetylcholine receptor (n‐AChR) from Torpedo marmorata were detected in sera from rabbits with experimental myasthenia but not in sera from patients with myasthenia gravis or in rabbit antisera to a partly purified skeletal muscle antigen. Antibodies to this muscle antigen were demonstrated in sera from patients with myasthenia gravis but not in sera from rabbits with experimental myasthenia. The results indicate that there is no immunological cross‐reaction between the muscle antigen and n‐AChR from Torpedo marmorata, and little or no cross‐reactivity between these n‐AChR antibodies and possible muscle n‐AChR antibodies in myasthenia gravis patients.
The Immunoglobulin Receptors on B Cells Bind Antigen, Focus Activation Signals to Them and Initiate Antigen‐Presentation
Authors: MÖLLER G. , ALARCÓN‐RIQUELME M. , CLINCHY B. , GONTIJO C. M. , HÖIDÉN I.
Published: September 2006

We do not agree with the analysis of Langman and Cohn on the function of Ig receptors. We have reviewed the available literature regarding anti‐Ig activation of B cells and found it contradictory and unconvincing. We have presented experimental evidence on the inability of Ig receptors on B cells to mediate activation or tolerogenic signals. We suggest that the Ig receptors serve to focus antigen to specific B cells so the B cells can be activated by TI antigens or helper T cells. The Ig molecules also bind foreign antigen and thereby initiate internalization and antigen processing. The processed peptides are exported to the membrane, where they associate with MHC class II antigens, thus transforming B cells into efficient antigen‐presenting cells.
Allorecognition of HLA DR2 and DR5 Molecules by V‐Beta‐8‐Positive T‐Cell Clones
Authors: WILSON K. E. , BALL E. , STASNY P. , CAPRA J. D.
Published: September 2006

V‐beta‐8‐positive T cells were isolated from human peripheral blood lymphocytes using a monoclonal antibody specific for the Vβ8 family. Alloreactive T‐cell lines were generated by stimulation with mononuclear cells from individuals homozygous for HLA DRI‐DR9. Cloned Vβ8‐positive T cells were then assayed for alloreactivity based on a proliferative assay using irradiated B‐cell lines. Vβ8‐positive T‐cell clones alloreactive to DR2 and DR5 molecules were chosen for further study based on the association of these MHC antigens with autoimmune disease. DNA sequence analysis confirmed the use of the Vβ8 gene family as well as providing information on the use of the V, D, J and N segments in these alloreactive T‐cell clones.
Lymphocyte‐Selective Cytostatic and Immunosuppressive Effects of Mycophenolic Acid in Vitro: Role of Deoxyguanosine Nucleotide Depletion
Authors: EUGUI E. M. , ALMQUIST S. J. , MULLER C. D. , ALLISON A. C.
Published: September 2006

Mycophenolic acid (MPA), an inhibitor of inosine monophosphate dehydrogenase, in nanomolar concentrations blocks proliferative responses of cultured human, mouse and rat T lymphocytes and B lymphocytes to mitogens or in mixed lymphocyte reactions. The inhibitory effect of MPA on lymphocyte proliferation is reversed by addition to culture media of deoxyguanosine or guanosine but not by addition of deoxyadenosine or adenosine. The findings suggest that the principal mechanism of action of low concentrations of MPA is depletion of deoxyguanosine triphosphate which is required for DNA synthesis. In immunosuppressive doses, MPA does not affect the formation of IL‐1 by LPS‐activated human peripheral blood monocytes. Unlike cyclosporin A and FK‐506, MPA does not inhibit the formation of IL‐2 and the expression of the IL‐2 receptor in mitogen‐activated human T lymphocytes. MPA suppresses mixed lymphocyte reactions when added 3 days after their initiation. These findings suggest that MPA does not inhibit early responses of T and B lymphocytes lo mitogenic or antigenic stimulation but blocks the cells at the time of DNA synthesis. The cytostatic effect of MPA is more potent on lymphocytes than on other cell types, such as fibroblasts and endothelial cells. MPA also inhibits antibody formation by polyclonally activated human B lymphocytes. MPA is an immunosuppressive agent reversibly inhibiting proliferation of T and B lymphocytes and antibody formation, with a profile of activity different from that of other immunosuppressive drugs. Human T and B lymphocytic and promonocytic cell lines are highly sensitive to the antiproliferative effects of MPA, whereas the erythroid precursor cell line K562 is less susceptible. The effect of MPA on cells of the monocyte‐macrophage lineage could exert long‐acting anti‐inflammatory activity. MPA or analogues may have therapeutic utility in diseases such as rheumatoid arthritis, for prevention of allograft rejection and in lymphocytic or monocytic leukaemias and lymphomas.
Lymphocyte‐Selective Antiproliferative and Immunosuppressive Effects of Mycophenolic Acid in Mice
Authors: EUGUI E. M. , MIRKOVICH A. , ALLISON A. C.
Published: September 2006

Mycophenolic acid (MPA), administered orally to mice, inhibits the formation of antibodies to sheep erythmcytes. MPA also suppresses, in a dose‐related manner, the generation of cytotoxic T‐lymphocytes against allogeneic cells in mice and prevents the elimination of allogeneic cells. However, short‐term treatment of T lymphocytes with therapeutically attainable doses of MPA does not inhibit the effector phase of cytotoxicity. Doses of MPA sufficient to prevent allograft rejection in mice inhibit the incorporation of labelled thymidine into DNA in the lymph nodes and spleen of mice but not in the germinal cells of the testis or in the basal epithelial cells of the Jejunum; they do not produce neutropenia, anaemia or thrombocytopenia. These observations show that MPA has lymphocyte‐selective anti‐proliferative effects in vivo and can inhibit both cell‐mediated and humoral immune responses without major side effects. Reasons why MPA has advantages over currently used and recently identified immunosuppressive drugs are discussed. The experimental system described provides a convenient in vivo assay for the capacity of drugs to inhibit allograft rejection.
A Monoclonal Antibody to the Mycobacterial 65kDa Heat Shock Protein (ML 30) Binds to Cells in Normal and Arthritic Joints of Rats
Authors: KLEINAU S. , SÖDERSTRÖM K. , KIESSLING R. , KLARESKOG L.
Published: September 2006

A monoclonal antibody reactive with the mycobacterial 65 kDa heal shock protein (ML 30) was investigated for reactivity with biopsies from normal rat joints and with inflamed joints due to adjuvant arthritis (AA) or collagen induced arthrilis (CIA).

Immunohistochemical stainings with the ant‐hsp 65 antibody on paralVm sections from normal rat joints revealed a weak but exclusive staining of cells within the synovial lining. Also normal chondrocytes and bone marrow cells showed oceasioniil staining.

In biopsies from inflamed joints obtained from rats suffering from AA or CIA. an intense staining with ML 30 was seen with in the Ciirtilage‐pannus junction as well as sites of bone erosion. An increased staining, compared with the normal, was also seen in chondroeytes of the eroded cartilage and in some bone marrow cells. No staining with ML 30 was seen in biopsies from inflammatory lesions due to delayed type hyperscnsitivity reactions in the skin of rats. Reactivity of ML 30 was also seen in a Western blot assay performed on lysates from inflamed synovia from rats with CIA, preferentially with a component slightly below 60 kDa in molecular weight.

The demonstration of epitopes cross‐reactive with hsp 65 of mycobacteria in normal and. in higher quantity, in arthritic rat joints, suggests, together with our preliminary biochemical findings, that a recently identified mammalian counterpart to bacterial hsp 65 is both preferentially expressed in normal joints and subject to increased expression in arthritis of different aetiologies.
Expression of CD40 and CD43 during Activation of Human B Lymphocytes
Authors: BJÖRCK P. , AXELSSON B. , PAULIE S.
Published: September 2006

CD40 and CD43 arc two cell‐surface glycoproteins that appear to be functionally involved in the growth stimulation of human B cells. Whereas CD40 is structurally similar to the NGF receptor and is present on all resting B cells. CD43 displays no homology to other known proteins and is expressed only on a subpopulation of these cells. To further understand the extra‐ and intracellular signals regulating these molecules and in which stage of activation they may play a role, we used various activation strategies and studied their expression on tonsillar B cells. As expected, activation of protein kinase C by TPA increased both CD40 and CD43. In contrast, a rise in intracellular Ca2+, e.g. by ionomycin, did not influence the expression of these antigens. However, in the presence of TPA, ionomycin further up‐regulated CD43 but not CD40. Anti‐IgM behaved similarly to ionomycin suggesting that the effect of this reagent was due primarily to its ability to increase intracellular Ca2+. Of three interleukins(lL‐2. IL‐4 and IL‐6) only IL‐4 had a significant effect when used alone in that it up‐regulated CD40 but not CD43. However, in Ihe presence of anti‐IgM, both IL‐2 and IL‐4 synergistically up‐regulated the two antigens. Complementation of antigen receptor stimulation with TPA or IL‐4 increased CD4U during the first 24 h. whereas up‐regulation of CD43 did not occur until 24 to 4S h after stimulation. With regard both to up‐regulation in response to different stimuli and to kinetics, CD40 expression paralleled that of the early activation antigen CD23, whereas CD43 was induced in parallel with the transferrin receptor (CD71). Taken together, our results suggests that the expression of CD40 and CD43 is regulated by different intracellular signals and that CD40 may be important during early activation, whereas CD43 may have its major function during later stages of B‐cell differentiation. These assumptions are in line with the observations that CD4U antibodies can directly activate resting B cells and that CD43 are retained on plasma cells.
Immune Response to Prolonged Intestinal Exposure to Antigen
Authors: KANTELE A.
Published: September 2006

The influence of prolonged intestinal antigen exposure on the immune response in humans was investigated. Two groups of volunteers were vaccinated orally with live Salmonella typhi Ty 2la given in enteric‐coated capsules three (group 3 × E) or six (group 6 × E) at 2‐diiy intervals. The immune response was followed for I month by enumerating the antibody‐secreting cells (ASC) in the peripheral blood. Soon after vaccination specific ASC were observed in the blood of all volunteers. In group 3 × E, the response peaked on day 5 or 7 and had faded away by day 14. In group 6 × E. by contrast, there was no clear single peak of the response, and the ASC numbers were high in several consecutive measurements. On day 14. considerable numbers of ASC were still detected in all cases: the responses had mostly faded away by day 22. These results show that prolonged exposure to antigen in the intestine induces a prolonged response of specific ASC in peripheral blood. This is an important prerequisite for the application of the ASC assay to study mucosal infections, in which the actual time of onset is often unknown. In addition, the findings suggest that the ASC assay might offer new possibilities for assessing the persistence of microbial antigens in infections.
A Rapid Microtitration Plate Assay for Non‐Specific Esterase
Authors: SONNE O. , PEDERSEN K. , KUDAHL K. , FISKER S.
Published: September 2006

A simple and convenient colorimetric assay for the quantification of non‐specific esterase is described. The assay takes advantage of the microtitration plate format, and the high capacity of repetitive dispensers and the microplate reader for this format. The assay is well suited for the quantification changes in the esterase activity in homogeneous cell populations like monocytes maturing into macrophages.
Significant reduction in blood loss in patients undergoing minimal extracorporeal circulation
Authors: Gerritsen W. B. , Van Boven W. J. , Wesselink R. M. , Smelt M. , Morshuis W. J. , Van Dongen H. P. , Haas F. J. , Aarts L. P.
Published: September 2006

summary Several recent studies have shown differences in blood loss and allogeneic transfusion requirements between on‐pump and off‐pump coronary artery bypass grafting (CABG). Recently a new concept, the mini‐extracorporeal circulation, was introduced to minimize the side effects of extracorporeal circulation. Therefore, there are no data comparing the three techniques with special emphasis to blood loss and transfusion requirements. Two hundred and eighty‐five patients undergoing first‐time coronary artery bypass grafting were retrospectively matched for number of grafts, age and sex. Ninety‐five patients underwent surgery with the off‐pump CABG (OPCAB) technique, 97 patients using conventional CABG with cold cardioplegia (CCABG) and 93 patients with the mini‐extracorporeal circuit with warm blood cardioplegia (MCABG). Blood loss for the CCABG group with a mean loss of 819 ± 557 mL and the OPCAB group with a mean loss of 870 ± 768 mL was significant different compared to the MCABG group with a mean loss of 679 ± 290 mL. The use of units red blood cell units was significantly higher for CCABG group and OPCAB group compared to the MCABG group. On the day of operation the use of platelet concentrate was significantly higher for the CCABG group compared to MCABG group. As a consequence of improvements of several components of the mini heart lung machine, significantly less blood products are needed in MCABG patients. The expected reduced need for transfusion when the pump was completely avoided could not be confirmed in this single retrospective cohort study.
Transfusion‐related acute lung injury in the paediatric patient: two case reports and a review of the literature
Authors: Church G. D. , Price C , Sanchez R , Looney M. R.
Published: September 2006

summary Transfusion‐related acute lung injury (TRALI) is increasingly recognized as a major complication of transfusion therapy; it was the leading cause of transfusion‐related fatalities in the United States in 2003. Most cases of TRALI that have been reported are in adult patients. We present two cases of TRALI that occurred in children and review the existing literature of paediatric TRALI. The paediatric TRALI case reports highlight two laboratory findings that can help in the diagnosis of TRALI: transient leucopenia and an elevated pulmonary oedema fluid/plasma protein ratio. These two simple diagnostic tests can help rule out other diagnoses and add confidence to the clinical diagnosis of TRALI. Finally, our first case also highlights the potential danger of directed maternal blood donations, which may increase the risk of paediatric TRALI.
Establishment of an HPA‐1‐ to ‐16‐typed platelet donor registry in China
Authors: Feng M. L. , Liu D. Z. , Shen W. , Wang J. L. , Guo Z. H. , Zhang X. , Du K. M. , Qian K. C. , Zhao T. M.
Published: September 2006

summary In order to determine gene frequencies of human platelet antigen (HPA) and establish a panel of accredited HPA‐1a, ‐2a, ‐4a, ‐5a and ‐6a‐negative donors as well as an HPA‐typed platelet donor registry, a total of 1000 Chinese donors of Han nationality (500 from north China and 500 from south China) were typed for HPA‐1 through ‐16 using a DNA‐based polymerase chain reaction with sequence‐specific primers genotyping method. The gene frequencies of HPA‐1b, ‐2b, ‐3b, ‐4b, ‐5b, ‐6bw, ‐10bw and ‐15b were 0·0060, 0·0485, 0·4055, 0·0045, 0·0140, 0·0135, 0·0005 and 0·4680, respectively. The HPA‐7bw, ‐8bw, ‐9bw, ‐11bw, ‐12bw, ‐13bw, ‐14bw and ‐16bw alleles were not found. The HPA‐2b and ‐5b homozygous donors were detected at low frequencies. The HPA mismatch probabilities potentially leading to alloimmunization in random platelet transfusion vary with a region from 0·1% to 37% depending on the distribution patterns of common and less common alleles in each system. This study provides a useful HPA‐typed plateletpheresis donor registry in China and could improve platelet antibody detection and HPA‐matched platelet transfusion in alloimmune thrombocytopenic patients.
Secularism, Criticism, and Religious Studies Pedagogy
Authors: Britt Brian
Published: September 2006

Abstract.  Secularization, the idea that religion would gradually diminish over time, was once widely assumed to be true by scholars of religion, but the unexpected resurgence of religious traditions has called it into question. Related debates on the distinction between religion and the secular have destabilized religious studies further. What does the crisis of secularization and secularism mean for the religious studies classroom? This essay proposes a model of religious criticism in the wake of secularism. No longer simply claiming a “view from nowhere,” students and instructors can (by observing standards of evidence, reason, and self‐disclosure) combine criticism with learning. Drawn from aesthetic and ethical traditions of criticism, religious criticism can be practiced by “teaching the conflicts” and through the pedagogical models of Freire and hooks.
Geographical variation, sex and age in Great Bittern Botaurus stellaris using coloration and morphometrics
Authors: DMITRENOK MARINA , PUGLISI LUCA , DEMONGIN LAURENT , GILBERT GILLIAN , POLAK MARCIN , BRETAGNOLLE VINCENT
Published: September 2006

Biometrics, plumage and bare‐part colour of 87 Great Bitterns Botaurus stellaris from the UK, France, Italy, Poland and Belarus, of known sex (sexed by behaviour, DNA or dissection), were analysed to provide reliable sexing and ageing criteria for this little‐known species, and to investigate geographical variation in biometrics. Four parameters were analysed: bill length, tarsus, wing length and body weight. We found little (though significant) geographical variation across Europe, but this was not clinal and we cannot exclude variation in measurement technique among observers. Males were significantly larger than females for all biometric parameters: a discriminant function based on these parameters was able to sex correctly all individuals. Body weight varied with season, especially for males. During the breeding period, lore colour was also a reliable sex‐criterion. Ageing proved more difficult and required a combination of iris colour (which darkens with age) and flight‐feather moult. From this, the largest sample size of known‐age Great Bitterns, we conclude that most previously published criteria for age determination of this species were wrong.
The influence of habitat management on the breeding success of the Great Bittern Botaurus stellaris in Britain
Authors: GILBERT GILLIAN , TYLER GLEN A. , DUNN CHRISTOPHER J. , RATCLIFFE NORMAN , SMITH KEN W.
Published: September 2006

Great Bitterns Botaurus stellaris have experienced a population decline in the UK, such that in 1997 the total number of breeding males was just 11. This study aimed to identify factors affecting productivity, and how management could be used to manipulate this. An intensive study of Great Bittern breeding success was conducted between 1997 and 2001. The date that males established their booming territories was closely correlated with when females started nesting. Wetter sites with greater fish densities had males that established their booming territories earlier in the season. However, only the date that males started booming determined when females started nesting. The mean clutch size of Great Bitterns was four and the only cause of nest failure was predation. Of eight nests suspected to be second attempts the mean interval between these first and second attempts was 12.25 ± 0.88 (sd) days (range 8–15). The fate of radiotagged chicks followed to fledging revealed that the overall probability of a chick surviving to fledge was 39.1%. Daily losses of Great Bittern chicks due to starvation/exposure accounted for 76.25% and predation 21.25%. The youngest chicks in poor condition were most likely to die, particularly in periods of high rainfall. A simulated renesting model allowed estimation of Great Bittern productivity as 1.24 chicks per female and 1.52 nesting attempts per female. Habitat management, or lack of water control that resulted in sites being drier in spring, delayed nesting, although statistically there was no difference in productivity compared with wetter sites.
The effect of breeding status on the timing of moult in Mute Swans Cygnus olor
Authors: MCCLEERY R. H. , PERRINS C. M. , WHEELER D. , GROVES S.
Published: September 2006

It is well known that in breeding Mute Swans Cygnus olor males initiate moult 4–6 weeks after their mate, and that in non‐breeding flocks males and females moult at about the same time. Here we show that mated pairs that have lost their young moult at the same time, implying that the male is able to avoid the delay in moult at very short notice.
Youth transitions and going to university: the perceptions of students attending a geography summer school access programme
Authors: Hopkins Peter E
Published: September 2006

This paper contributes to understandings of youth transitions in childhood and youth geographies through the use of a participatory diagramming exercise with students studying geography in a summer school access programme at a Scottish university. In particular, the paper explores young people's perceptions about adult/child binaries and their hopes and fears in applying to university. The discussion highlights the extended nature of youth transitions: the usefulness of participatory diagramming as a research method and teaching technique for this group; and the consequences that the increasing interest in childhood and youth geographies might have on teaching and learning in human geography.