bluuebunny/crossref_metadata_2025 huggingface dataset:
Droughts and anti‐droughts: the low flow hydrology of Australian rivers
Authors: McMahon T. A. , Finlayson B. L.
Published: June 2003

1. Droughts are not easily defined other than by culturally driven judgements about the extent and nature of impact. Natural ecosystems are adapted to the magnitude and frequency of dry periods and these are instrumental in controlling the long term functioning of these systems.

2. In unregulated rivers, low flows are derived from water in long‐term storage in the catchment, commonly as shallow groundwater. Four types of low flow sequences are evident for representative rivers from each of the seven flow regime zones in Australia and an arid zone stream: perennial streams with low annual flow variability that have seasonal low flows but do not cease to flow; perennial streams with high annual variability that cease to flow in extreme years; ephemeral streams that regularly cease to flow in the dry season; and arid zone streams with long and erratic periods of no flow.

3. Although Australian rivers record runs of consecutive years of low flows longer than would be expected theoretically, the departures from the expected are not statistically significant. Trends and quasi‐cycles in sequences of low‐flow years are observed over decadal time scales.

4. Examples of the effects of river regulation on low flows in southern Australia indicate that, while in detail the impacts of regulation vary, in general regulation mitigates the severity of low flows.

5. It is our contention that the indigenous biota of Australian rivers are adapted to the naturally occurring low flow conditions and that, while there is considerable scientific interest in the effects of climate change on stream ecology, such studies have little practical relevance for the management of indigenous biota in unregulated rivers.

6. The changes brought about by the regulation of rivers are much more rapid and dramatic than those which might occur as a result of climate change and it is possible to develop management procedures to mitigate them. In regulated rivers, the real problem may be ‘anti‐droughts’– the removal of significant natural low‐flow events from the flow pattern.
Characterization of extrathymic CD8αβ T cells in the liver and intestine in TAP‐1 deficient mice
Authors: Tsukada Chika , Miyaji Chikako , Kawamura Hiroki , Miyakawa Ryoko , Yokoyama Hisashi , Ishimoto Yuiko , Miyazawa Shinobu , Watanabe Hisami , Abo Toru
Published: June 2003

TAP‐1 deficient (−/−) mice cannot transport MHC class I antigens onto the cell surface, which results in failure of the generation of CD8+ T cells in the thymus. In a series of recent studies, it has been proposed that extrathymic T cells are generated in the liver and at other extrathymic sites (e.g. the intestine). It was therefore investigated whether CD8+ extrathymic T cells require an interaction with MHC class I antigens for their differentiation in TAP‐1(−/−) mice. Although CD8+ thymically derived T cells were confirmed to be absent in the spleen as well as in the thymus, CD8αβ+ T cells were abundant in the livers and intestines of TAP‐1(−/−) mice. These CD8+ T cells expanded in the liver as a function of age and were mainly confined to a NK1·1−CD3int population which is known to be truly of extrathymic origin. Hepatic lymphocytes, which contained CD8+ T cells and which were isolated from TAP‐1(−/−) mice (H‐2b), responded to neither mutated MHC class I antigens (bm1) nor allogeneic MHC class I antigens (H‐2d) in in vitro mixed lymphocyte cultures. However, the results from repeated in vivo stimulations with alloantigens (H‐2d) were interesting. Allogeneic cytotoxicity was induced in liver lymphocytes in TAP‐1(−/−) mice, although the magnitude of cytotoxicity was lower than that of liver lymphocytes in immunized B6 mice. All allogeneic cytotoxicity disappeared with the elimination of CD8+ cells in TAP‐1(−/−) mice. These results suggest that the generation and function of CD8+ extrathymic T cells are independent of the existence of the MHC class I antigens of the mouse but have a limited allorecognition ability.
Evidence for the immunosuppressive role of nicotine on human dendritic cell functions
Authors: Nouri‐Shirazi Mahyar , Guinet Elisabeth
Published: June 2003

Nicotine alters a wide range of immunological functions, including innate and adaptive immune responses. To date, no studies have been reported showing the immunoregulatory effects of nicotine on dendritic cells (DCs), which are critical cells for initiation of cell‐mediated immunity against infection and neoplastic diseases. In this work, we report that, in a nicotinic environment, monocyte‐derived DCs manifest lower endocytic and phagocytic activities. Interestingly, although immature DCs undergo maturation in response to bacterial antigen lipopolysaccharide, they produce decreased levels of pro‐inflammatory cytokines, notably interleukin‐12, and reveal a reduced ability to stimulate antigen‐presenting cell‐dependent T‐cell responses. Importantly, the reduction in T‐cell responses is associated with a diminished ability of DCs to induce differentiation and expansion of type 1 T cells, as evidenced by a decreased frequency of interferon‐γ‐producing effector cells. These results strongly suggest that nicotine can exert its immunosuppressive effects on immune surveillance through functional impairment of the DC system.
Differential T‐cell activation by B7‐1 expression
Authors: Li Wei , Rosenzweig Anthony , Huber Brigitte T.
Published: June 2003

T‐cell receptor‐mediated T‐cell activation requires cosimulation signal, which can be provided by B7‐1 molecule. Our previous study demonstrated that the coexpression of a covalent peptide/major histocompatibility complex class II molecule complex and costimulatory molecule B7‐1 by recombinant adenovirus leads to synergy in peptide‐specific T‐cell activation. However, the viral antigen‐specific T‐cell activation is not enhanced by B7‐1 expressed by the adenovirus. To verify the differential T cell activation by B7‐1 and investigate its underlying mechanisms, we constructed an adenovirus coexpressing a covalent complex of hen egg lysozyme peptide/I‐Ak (HEL46–61/I‐Ak) and B7‐1 in the present study. In vivo studies revealed that HEL46–61‐specific T‐cell response, but not viral antigen‐specific T‐cell response, was enhanced by B7‐1 expression mediated by the adenovirus, suggesting that exogenous B7‐1 expression may regulate T‐cell response to these two different antigens through distinct mechanisms. Furthermore, our results revealed that antigen‐presenting cells were unsusceptible to adenovirus infection in vivo. Based on these findings, the possible mechanism of differential B7‐1 costimulation on peptide‐specific and viral antigen‐specific T‐cell activation is discussed.
Protein kinase C is involved in 2B4 (CD244)‐mediated cytotoxicity and AP‐1 activation in natural killer cells
Authors: Chuang Samuel S. , Lee Jae‐Kyung , Mathew Porunelloor A.
Published: June 2003

2B4 (CD244) is a member of the CD2 subset of the immunoglobulin superfamily and functions as a triggering molecule on natural killer (NK) cells. Previously, we have found that 2B4‐mediated activation of NK cells involves complex interactions involving LAT, Ras, Raf, ERK and p38 and that cytolytic function and cytokine production may be regulated by distinct pathways. Here we assessed the role of protein kinase C (PKC) in 2B4‐mediated cytotoxicity of YT cells, a human NK cell line. Our data indicate that PKC‐δ is activated upon stimulation with monoclonal antibody against 2B4. Treatment with the PKC inhibitor, bisindolylmaleimide I (Gö6850), of YT cells or YT cells depleted of Ca2+‐dependent isoforms of PKC prior to 2B4 stimulation, resulted in inhibition of natural cytotoxicity and redirected antibody‐dependent cellular cytotoxicity. However, inhibition of PKC failed to block 2B4 stimulation of interferon‐γ secretion as opposed to pretreatment with LY294002, a phosphoinositide 3‐kinase inhibitor. We also examined the effect of phorbol 12‐myristate 13‐acetate (PMA) induction on 2B4 gene transcription. PMA induction resulted in a more than two‐fold increase of 2B4 transcription. However, when we introduced a three‐base substitution mutation to disrupt the activator protein‐1 binding site at (−106 to −100) in the 2B4 promoter, we found complete loss of transcriptional activity, including the two‐fold increase due to PMA induction of PKC. The present study indicated that PKC may play an important role in 2B4 signalling and activator protein‐1 activation.
The role of interferon‐γ, nitric oxide and lipopolysaccharide in intestinal graft‐versus‐host disease developing in F1‐hybrid mice
Authors: Ellison Cynthia A. , Natuik Shannon A. , Mcintosh Alan R. , Scully Sheila A. , Danilenko Dimitry M. , Gartner John G.
Published: June 2003

(C57BL/6 × DBA/2)F1‐hybrid mice injected with lymphoid cells from wild‐type, C57BL/6 donors develop acute, lethal graft‐versus‐host disease (GVHD) in which the intestine is a major target. In its destructive phase intestinal GVHD is characterized by apoptosis of intestinal crypt epithelial cells and the development of endotoxaemia. Injection of as little as 10 μg endotoxin is lethal in mice with acute GVHD, and associated with the release of large amounts of tumour necrosis factor‐α (TNF‐α) into the serum. To explore the role of interferon‐γ (IFN‐γ) in the pathogenesis of intestinal GVHD we used IFN‐γ gene knockout (gko) mice as donors. Recipients of grafts from these donors did not develop intestinal GVHD and, unlike recipients of wild‐type grafts, did not die when injected with lipopolysaccharide (LPS). We also found that injection 10 μg LPS into recipients of wild‐type grafts induced apoptosis of intestinal epithelial crypt cells and was associated with a burst of nitric oxide production in the intestine. Administration of Nωnitro l‐arginine methyl ester blocked this response. In contrast, LPS did not induce either intestinal epithelial cell apoptosis or increased nitric oxide production in recipients of IFN‐γ gko grafts. These findings indicate that donor‐derived IFN‐γ is instrumental for the development of intestinal GVHD. In a previous study we showed that recipients of IFN‐γ gko grafts develop high levels of LPS‐induced TNF‐α release. When our current data are viewed in the context of this observation, they suggest that intestinal epithelial cell apoptosis in the parent→F1‐hybrid model of acute GVHD is mediated primarily by nitric oxide rather than TNF‐α, and that this depends on donor‐derived IFN‐γ.
Dendritic cell maturation enhances CD8+ T‐cell responses to exogenous antigen via a proteasome‐independent mechanism of major histocompatibility complex class I loading
Authors: Robson Neil C. , Beacock‐Sharp Helen , Donachie Anne M. , Mowat Allan McI.
Published: June 2003

Immune stimulating complexes (ISCOMS) containing the saponin adjuvant Quil A are vaccine adjuvants that induce a wide range of immune responses in vivo, including strong class I major histocompatibility complex (MHC) ‐restricted cytotoxic T‐lymphocyte activity. However, the antigen‐presenting cell responsible for the induction of these responses has not been characterized. Here we have investigated the role of dendritic cells (DC) in the priming of antigen‐specific CD8+ T cells in vitro by ISCOMS containing ovalbumin. Resting bone marrow DC pulsed with ovalbumin ISCOMS efficiently prime resting CD8+ T cells through a mechanism that is transporter associated with antigen processing (TAP) dependent, but independent of CD40 ligation and CD4+ T‐cell help. Lipopolysaccharide‐induced maturation of DC markedly enhances their ability to prime CD8+ T cells through a mechanism which is also independent of CD4+ T‐cell help, but is dependent on CD40 ligation. Furthermore, DC maturation revealed a TAP‐independent mechanism of CD8+ T‐cell priming. Our results also show that class I MHC‐restricted presentation of ovalbumin in ISCOMS by DC is sensitive to chloroquine and brefeldin A but insensitive to lactacystin. We suggest that DC may be the principal antigen‐presenting cells responsible for the priming of CD8+ T cells by ISCOMS in vivo and that targeting these vectors to activated DC may enhance their presentation via a novel pathway of class I antigen processing.
Apolipoprotein E modulates immune activation by acting on the antigen‐presenting cell
Authors: Tenger Charlotta , Zhou Xinghua
Published: June 2003

Apolipoprotein E (ApoE) is synthesized by a variety of cells including macrophages. These cells activate T lymphocytes by antigen presentation, while the T‐cell cytokine, interferon‐γ, inhibits macrophage ApoE expression. ApoE inhibits T‐cell proliferation in culture but its role in immune responses has been unclear. The ApoE‐deficient (E0) mouse permits an evaluation of the immunological role of ApoE. We have analysed T‐cell responses to an exogenous antigen (ovalbumin) and polyclonal mitogen (concanavalin A) in E0 and ApoE+/+ mice. Macrophages of E0 mice stimulated T‐cell activation more effectively as antigen‐presenting cells than macrophages from ApoE+/+ mice. Both proliferation and interferon‐γ secretion were enhanced in T cells activated in the context of antigen‐presenting cells from E0 mice. Since the macrophage–T‐cell interaction depends on interactions between cell surface molecules, we assessed the expression of such molecules after in vivo stimulation with interferon‐γ. This treatment caused an increased expression of the co‐stimulatory surface proteins CD40 and CD80, and also of the major histocompatibility complex class II molecules I‐Ab on macrophages of E0 mice compared with ApoE+/+. Our data suggest that ApoE inhibits T‐cell activation by reducing the density of immune stimulatory proteins on antigen‐presenting cells.
Efficient antigen presentation of soluble, but not particulate, antigen in the absence of Wiskott–Aldrich syndrome protein
Authors: Westerberg Lisa , Wallin Robert P. A. , Greicius Gediminas , Ljunggren Hans‐Gustaf , Severinson Eva
Published: June 2003

B cells and dendritic cells, lacking functional Wiskott–Aldrich syndrome protein (WASP), have aberrant formation of membrane protrusions. We hypothesized that protrusions may play a role in antigen presentation, and consequently, that impaired antigen presentation may be an underlying factor of the immune deficiency in patients with Wiskott–Aldrich syndrome. In this paper, we investigated the antigen presentation capacity of B cells and dendritic cells from WASP knockout mice, using soluble and particulate antigen, to CD4+ T cells from T‐cell receptor transgenic DO11.10 mice. As antigen we used soluble ovalbumin (OVA), a peptide thereof (amino acids 323–339) or bacteria expressing OVA. We found that WASP‐deficient B cells and dendritic cells efficiently processed and presented soluble OVA protein as well as its peptide in vitro, inducing proliferation and cytokine production from CD4+ T cells. Antigen presentation of soluble protein was efficient also in vivo, because immunization of WASP‐deficient mice with OVA elicited proliferation of transferred, fluorescent‐labelled, CD4+ T cells. Although we could detect uptake of bacteria in dendritic cells, processing and presentation of bacterial‐expressed OVA was impaired in WASP‐deficient dendritic cells. In conclusion, our data suggest that WASP is not needed for processing and presentation of soluble antigen, but that efficient presentation of particulate antigen require WASP.
Anti‐human immunodeficiency virus‐gag CD8+ memory T cells generated in vitro from Listeria‐immunized mice
Authors: Rayevskaya Marina , Kushnir Natasha , Frankel Fred R.
Published: June 2003

The goal of vaccination is the generation of immune memory, an immune state that permits rapid and intense recall responses to a pathogen. Considerable effort is being made to understand the nature of memory T cells. We report here that by extending the length of in vitro culture following a single restimulation with specific peptide, preparations of highly enriched, highly active antigen‐specific CD8+ memory T cells could be obtained. These cultures were begun with splenocytes from mice primed by infection either with an attenuated strain of Listeria monocytogenes or vaccinia virus, both expressing the human immunodeficiency virus‐1‐gag gene. In the cultures, antigen‐specific cytotoxic T lymphocyte (CTL) activity reached a maximum at about 9 days and thereafter fell to negligible values. Concomitant with the fall of CTL activity, however, we observed enrichment for a subset of CD11ahigh antigen‐specific gag‐tetramerpos CD8+ T cells. The cells showed little or no 4‐hr CTL activity, but had high delayed (18‐hr) CTL activity, and very high cytolytic activity after restimulation. They rapidly expressed interferon‐γ production. Their growth and survival after sorting was completely dependent on interleukin‐2 or ‐15. As few as 5000 of the fluorescence‐activated cell sorting‐purified cells protected recipients against challenge 3 months after transfer. In response to the challenge, the cells repopulated lymphoid and non‐lymphoid organs and showed a sizeable increase in number. The cells therefore demonstrate high protective activity for long periods of time. These cultured cells are thus a potential source of enriched natural memory T cells for reperfusion studies and in which the mechanisms that underlie the generation, differentiation and persistence of memory can be examined.
Oestradiol regulation of antigen presentation by uterine stromal cells: role of transforming growth factor‐β production by epithelial cells in mediating antigen‐presenting cell function
Authors: Wira Charles R. , Rossoll Richard M.
Published: June 2003

We have previously shown that oestradiol treatment of ovariectomized rats for 3 days inhibits antigen presentation by uterine stromal cells at a time when oestradiol increases the numbers of antigen‐presenting cells (APC) in the uterine stroma. In the present study, we found that oestradiol treatment for 1 day is sufficient to inhibit antigen presentation by stromal cells. To define the mechanism(s) of this inhibition, we examined the effect of cytokines and found that exogenous transforming growth factor‐β (TGF‐β) inhibits antigen presentation when stromal cells from saline‐ but not oestradiol‐treated animals are incubated with ovalbumin (OVA)‐specific T cells and OVA. In contrast, antigen presentation by uterine epithelial cells was not affected by TGF‐β. In other studies, the acute inhibitory effect of oestradiol (1 day) on stromal antigen presentation is fully reversed when anti‐TGF‐β antibody is added to the culture media. When given for 3 days, oestradiol inhibition of antigen presentation is partially reversed by anti‐TGF‐β antibody at a time when antibodies to tumour necrosis factor‐α and interleukin‐10 have no effect. To determine whether uterine epithelial cells produce TGF‐β, epithelial cells were grown to confluence on transwell inserts. Our findings indicate that uterine epithelial cells produce biologically active TGF‐β which is preferentially released basolaterally in the direction of underlying stromal cells. When oestradiol is given to ovariectomized rats 1 day before sacrifice, TGF‐β production by epithelial cells increases within 24 hr in culture, relative to saline controls. Taken together, these results suggest that oestradiol inhibition of stromal cell antigen presentation is mediated through the stimulatory effect of oestradiol on TGF‐β production by epithelial cells.
Appearance of the LAT protein at an early stage of B‐cell development and its possible role
Authors: Oya Kazuyuki , Wang Jiyang , Watanabe Yumi , Koga Ritsuko , Watanabe Takeshi
Published: June 2003

The linker protein LAT is expressed mainly in T and natural killer (NK) cells. LAT‐deficient mice have an arrest of intrathymic T‐cell development at the CD4+ CD8+ stage and lack mature T cells in the periphery. However, no gross abnormality in development and function of the B and NK cells has been described. Here we report that LAT is expressed in mouse progenitor B (pro‐B) and precursor B (pre‐B) cells, but not in immature or mature B cells. LAT in pre‐B cells becomes tyrosine phosphorylated upon cross‐linking of the pre‐B‐cell receptor (pre‐BCR) by anti‐µ antibody. Incubation of 1xN/2b (mouse pre‐B‐cell line) cells or bone marrow cells from µMT/µMT mice, which lack B cells after the small pre‐B‐cell stage, with anti‐Igβ antibody resulted in the downregulation of LAT expression. Transgenic mice which expressed LAT protein in B‐lineage cells showed an increased proportion of pro‐ and large pre‐B cells in the bone marrow and a remarkable reduction in the numbers of mature B cells in peripheral lymphoid tissues. Collectively, the present results indicate that LAT is expressed in the cells at the early stages of B‐lineage development, but is absent in immature and mature B cells. LAT may play a crucial role in the negative regulation of B‐cell development at the transition from pre‐B to mature B‐cell stages, and signal(s) via the pre‐BCR may extinguish LAT expression, thus allowing pre‐B‐cell differentiation towards the mature B‐cell stage.
Effects of cyclosporin A and a rapamycin derivative (SAR943) on chronic allergic inflammation in sensitized rats
Authors: Eynott Paul R. , Salmon Michael , Huang Tung‐Jung , Oates Timothy , Nicklin Paul L. , Chung K. Fan
Published: June 2003

Immunomodulators such as cyclosporin A (CsA) and SAR943 (32‐deoxorapamycin) inhibit single allergen‐induced allergic inflammation such as eosinophilic and lymphocytic infiltration and mRNA expression for interleukin (IL)‐4 and IL‐5. We examined the effects of CsA and SAR943, administered orally, on asthmatic responses in a rat model of chronic allergic inflammation. Sensitized Brown‐Norway (BN) rats were exposed to ovalbumin (OVA) aerosol every third day on six occasions. CsA (5 mg/kg/day), SAR943 (2·5 mg/kg/day) or vehicle (Neoral™) was administered orally, once a day, from days 10 to 21 (a total of 12 doses). We measured eosinophilic and T‐cell inflammation in the airways, proliferation of airway cells by incorporation of bromodeoxyuridine (BrdU) and bronchial responsiveness to acetylcholine. CsA had no effects, while SAR943 inhibited airway smooth muscle (ASM, P < 0·05) and epithelial cell (P < 0·01) BrdU incorporation, and the number of CD4+ T cells (P < 0·05), without effects on BHR. ASM thickness was not significantly increased following chronic allergen exposure. Therefore, CsA and SAR943 have no effect on chronic eosinophilic inflammation, while SAR943, but not CsA, had a small effect on the proliferation of ASM and epithelium.
Induction of interleukin‐12 production in mouse macrophages by berberine, a benzodioxoloquinolizine alkaloid, deviates CD4+ T cells from a Th2 to a Th1 response
Authors: Kim Tae S. , Kang Bok Y. , Cho Daeho , Kim Seung H.
Published: June 2003

In this study we investigated whether berberine‐mediated induction of interleukin‐12 (IL‐12) production in antigen‐presenting cells could regulate a cytokine profile of antigen‐primed CD4+ T helper (Th) cells. Pretreatment with berberine induced IL‐12 production in both macrophages and dendritic cells, and significantly increased the levels of IL‐12 production in lipopolysaccharide‐stimulated macrophages and in CD40 ligand‐stimulated dendritic cells. Importantly, berberine pretreatment of macrophages increased their ability to induce interferon‐γ (IFN‐γ) and reduced their ability to induce IL‐4 in antigen‐primed CD4+ T cells. Berberine did not influence the macrophage cell surface expression of the class II major histocompatibility complex molecule, the co‐stimulatory molecules CD80 and CD86, and intracellular adhesion molecule‐1. Addition of neutralizing anti‐IL‐12p40 monoclonal antibody to cultures of berberine‐pretreated macrophages and CD4+ T cells restored IL‐4 production in antigen‐primed CD4+ T cells. The in vivo administration of berberine resulted in the enhanced induction of IL‐12 production by macrophages when stimulated in vitro with lipopolysaccharide or heat‐killed Listeria monocytogenes, leading to the inhibition of the Th type 2 cytokine profile (decreased IL‐4 and increased IFN‐γ production) in antigen‐primed CD4+ T cells. These findings may point to a possible therapeutic use of berberine or medicinal plants containing berberine in the Th type 2 cell‐mediated immune diseases such as allergic diseases.
Effects of functional Toll‐like receptor‐4 mutations on the immune response to human and experimental sepsis
Authors: Feterowski Carolin , Emmanuilidis Klaus , Miethke Thomas , Gerauer Klaus , Rump Martina , Ulm Kurt , Holzmann Bernhard , Weighardt Heike
Published: June 2003

Genetically determined responsiveness to microbial stimuli such as lipopolysaccharide (LPS) may affect the pathophysiology of human sepsis. The D299G mutation in human Toll‐like receptor‐4 (TLR4) impairs LPS signalling in homozygous and heterozygous individuals. To investigate whether the presence of the TLR4(D299G) mutation may correlate with the development or outcome of sepsis following major visceral surgery the presence of TLR4(D299G) mutation was analysed in 307 Caucasian patients (154 without and 153 with sepsis). Sepsis was caused in 84% of patients by polymicrobial infection. The presence of the mutant TLR4 did not significantly correlate with development or outcome of sepsis. Serum levels of tumour necrosis factor, interleukin (IL)‐10, and IL‐6 at sepsis onset did not significantly differ between patients carrying wild‐type and mutant TLR4. Moreover, studies in a murine model of polymicrobial septic peritonitis demonstrated that TLR4‐deficiency did neither influence the systemic cytokine response nor the development of organ injury. The results suggest that the signalling capacity of TLR4 as affected by loss‐of‐function mutations does not influence human or experimental sepsis caused by polymicrobial infection. Thus, in polymicrobial infection, other innate immune receptors may compensate for TLR4 defects.
Immature dendritic cells possess a sugar‐sensitive receptor for human mannan‐binding lectin
Authors: Downing Ian , Koch Claus , Kilpatrick David C.
Published: June 2003

Mannan‐binding lectin (MBL) is a collectin synthesized by the liver and secreted into the bloodstream. It has a receptor for microbial structures in its C‐type lectin domain and a separate receptor(s) located within its collagen‐like region for autologous phagocytic cells. Here we demonstrate that human peripheral blood adherent cells (monocytes) and monocyte‐derived dendritic cells are a source of MBL, and that a novel calcium‐dependent and sugar‐specific MBL receptor is up‐regulated in immature (CD1a‐positive) dendritic cells. These findings suggest a previously unsuspected autologous function for MBL, perhaps a regulatory role within the immune system.
Limited role of charge matching in the interaction of human immunoglobulin A with the immunoglobulin A Fc receptor (FcαRI) CD89
Authors: Pleass Richard J. , Dehal Prabhjyot K. , Lewis Melanie J. , Woof Jenny M.
Published: June 2003

Human immunoglobulin A (IgA) mediates protective effector mechanisms through interaction with specific cellular Fc receptors (FcαRI). Two IgA Fc interdomain loops (Leu257–Leu258 in the CH2 domain and Pro440–Phe443 in the CH3 domain) have previously been identified as critical for binding to FcαRI. On the receptor, the interaction site for IgA has been localized to the EC1 domain. The essential FcαRI residues involved are Tyr35, Tyr81 and Arg82, with contributions also from Arg52 and to a lesser extent from His85 and Tyr86. The basic nature of the side chains of some of the receptor residues implicated in ligand binding suggested that charge matching might play some role in the interaction. To address this possibility, we have generated five IgA1 mutants with point substitutions in acidic residues lying close to the putative interaction site and assessed their abilities to bind FcαRI on human neutrophils. Mutants E254A, E254L and E437A displayed affinities for FcαRI comparable to that of wild‐type IgA1, while mutants D255A and D255V had only slightly reduced affinities for the receptor. Therefore, electrostatic interactions appear unlikely to play a significant role in the IgA–FcαRI interaction. Moreover, the lack of effect of mutations in residues adjacent to those previously implicated in binding, reaffirms the importance of the interdomain loops in FcαRI binding.
Differential regulation of interleukin‐12 p40 and p35 induction via Erk mitogen‐activated protein kinase‐dependent and ‐independent mechanisms and the implications for bioactive IL‐12 and IL‐23 responses
Authors: Goodridge Helen S. , Harnett William , Liew Foo Y. , Harnett Margaret M.
Published: June 2003

Bioactive interleukin (IL)‐12 is a 70 000‐molecular weight (MW) heterodimeric cytokine comprising p40 and p35 chains. However, p40 can also form homodimers that antagonize bioactive IL‐12 or heterodimerize with p19 to form IL‐23, which exhibits overlapping yet distinct functions to that of IL‐12. We now define distinct signalling mechanisms that regulate lipopolysaccharide (LPS)‐mediated induction of IL‐12 p40 and p35 in macrophages and which may therefore provide therapeutic targets for precise and specific fine‐tuning of cytokine responses. Thus, whilst LPS‐induced p38 mitogen‐activated protein kinase (MAPkinase) activation is required for the induction of both p40 and p35 subunits, Erk MAPkinase signalling mediates negative feedback regulation of p40, but not p35, production. Such Erk MAPkinase activation is downstream of calcium influx and targets LPS‐induced IL‐12 p40 transcription by suppressing the synthesis of the transcription factor, interferon regulatory factor‐1 (IRF‐1). In contrast, negative regulation of the p35 subunit of IL‐12 occurs via a calcium‐dependent, but Erk‐independent, mechanism, which is likely to involve nuclear factor (NF)‐κB signalling. Finally, the importance of both Erk and p38 MAPkinases in differentially regulating IL‐12 p40 and p35 production is underscored by each being targeted by ES‐62, a product secreted by parasitic filarial nematodes to polarize the immune system towards an anti‐inflammatory phenotype conducive to their survival.
Information systems evaluation as an organizational institution – experience from a case study
Authors: Serafeimidis Vassilis , Smithson Steve
Published: June 2003

Abstract.  Information systems evaluation has strong social and organizational dimensions while existing research focuses primarily on the formal and positivistic characteristics. We investigate the organizational roles of the key stakeholders within the particular evaluation context (orientation). We focus on four evaluation orientations: control, sense‐making, learning and exploratory. Experience from a case study is used to analyse these concepts and relations. The case organization attempted to move from a state of an ad‐hoc evaluation practice to a more business‐driven one. New tools, processes, roles and responsibilities were developed during the attempt. We examine the behavioural and organizational integration aspects of evaluation during that journey.
An institutional perspective on developing and implementing intranet‐ and internet‐based information systems
Authors: Butler Tom
Published: June 2003

Abstract.  This paper adopts a constructivist, case‐based research strategy to examine the development and implementation of intranet‐ and internet‐based information systems (IS) in a single organization. Institutional theory is used to describe, explain and understand the commitments of social actors in the development of web‐based IS. The findings illustrate that: (1) social and organizational problems similar to those that beset ‘traditional’ IS development arise in the development and implementation of web‐based IS; (2) ‘top‐down’ development and implementation strategies give rise to more conflict and change management problems than ‘bottom‐up’ approaches; and (3) fostering high levels of commitment to organizational imperatives is key to the successful development and implementation of web‐based IS.
Pentacapsula neurophila sp.n. (Multivalvulida) from the central nervous system of striped trumpeter, Latris lineata (Forster)
Authors: Grossel G W , Dykova I , Handlinger J , Munday B L
Published: June 2003

Striped trumpeter, Latris lineata, are being experimentally cultured by the Tasmanian Aquaculture and Fisheries Institute at Taroona, Tasmania. Fish surviving over 30 days post‐hatching have frequently developed nervous aberrations associated with a severe granulomatous meningoencephalomyelitis. The myxozoan parasite Pentacapsula neurophila sp.n. was revealed as the parasite causing the disease in the striped trumpeter juveniles. Measurements made of isolated spores indicated that the organism was distinct from all previously described Pentacapsula species. This is the first report of a marine myxozoan parasite of the genus Pentacapsula in Australian waters.
Blood pressure independent association of microalbuminuria and left ventricular hypertrophy in hypertensive men
Authors: Dell'omo G. , Giorgi D. , Di Bello V. , Mariani M. , Pedrinelli R.
Published: June 2003

Abstract.  Dell'Omo G, Giorgi D, Di Bello V, Mariani M, Pedrinelli R (Università di Pisa, Pisa, Italy). Blood pressure independent association of microalbuminuria and left ventricular hypertrophy in hypertensive men. J Intern Med 2003; 254:–.

Background.  Rather unique amongst the prognostic predictors, microalbuminuria (MA, albuminuria: 15–200 μg min−1) is associated with several cardiovascular risk factors including left ventricular hypertrophy (LVH). The relationship, usually assumed to reflect an increased blood pressure (BP) load on the heart and the kidney, may, however, represent more than a haemodynamic correlate.

Methods.  To evaluate this possibility, we related MA to left ventricular mass index (LVMI) and other functional and structural echocardiographic parameters, office and 24‐h BP, weight, lipids and smoking status in 330 never treated nondiabetic hypertensive men.

Results.  The risk of MA increased linearly by ascending quartiles of LVMI and was 2.3‐fold higher in the presence of LVH after adjustment for age, left atrial size, mean fractional shortening. Systolic BP, either office or 24 h, and smoking status were the only additional independent predictors in multivariate logistic regression models. The BP‐adjusted risk of MA was about twofold higher in patients with LVH, either concentric or eccentric, and neutral in those with concentric remodelling compared with normal geometry.

Conclusions.  The association between elevated LVMI and MA independent of several other potential confounders, systolic BP in particular, is consistent with the existence of cardiac albuminuric factors, possibly of hormonal nature, which are to be identified more precisely. The extent to which LVH explains the predictive power of MA for morbid events independent of the BP load remains unknown.
Raloxifene, conjugated oestrogen and endothelial function in postmenopausal women
Authors: Duschek E. J. J. , Stehouwer C. D. A. , De Valk‐De Roo G. W. , Schalkwijk C. G. , Lambert J. , Netelenbos C.
Published: June 2003

Abstract.  Duschek EJJ, Stehouwer CDA, de Valk‐de Roo GW, Schalkwijk CG, Lambert J, Netelenbos C (VU University Medical Center, Amsterdam; Sophia Hospital, Zwolle; The Netherlands). Raloxifene, conjugated oestrogen and endothelial function in postmenopausal women. J Intern Med 2003; 254: 85–94.

Objectives.  To study the long‐term effects of raloxifene, a potential designer oestrogen, and oestrogen monotherapy on endothelial function in healthy postmenopausal women.

Design.  A 2‐year double‐blind, randomized and placebo‐controlled study in an Academic Medical Center. Fifty‐six hysterectomized but otherwise healthy postmenopausal women randomly received raloxifene hydrochloride 60 mg day−1 (n = 15) or 150 mg day−1 (n = 13), conjugated equine oestrogen (CEE) 0.625 mg day−1 (n = 15), or placebo (n = 13).

Main outcome measures.  Endothelial function as estimated from brachial artery flow‐mediated, endothelium‐dependent vasodilation and nitroglycerine‐induced endothelium‐independent vasodilation, and plasma levels of the endothelium‐derived regulatory proteins, von Willebrand factor (vWF) and endothelin (ET).

Results.  Raloxifene 60 mg did not significantly affect endothelial function. As compared with placebo, at 6 months of therapy, raloxifene 150 mg and CEE were associated with a mean increase in vWF of 25.5% point (95% CI 3.6–47.3) and 26.6% point (95% CI 6.9–46.3), respectively. At 24 months of therapy, raloxifene 150 mg was associated with a mean decrease in ET of 0.96 pg mL−1 (95% CI −1.57 to −0.36). Raloxifene nor CEE significantly affected endothelium‐dependent and/or ‐independent vasodilation.

Conclusions.  Our results suggest that long‐term therapy with raloxifene or oral CEE does not affect endothelium‐dependent vasodilation in healthy postmenopausal women. Raloxifene 150 mg day−1 might have both positive and negative effects on endothelium. The clinical significance of these findings remains to be investigated.
Effects of low‐dose warfarin and aspirin versus no treatment on stroke in a medium‐risk patient population with atrial fibrillation
Authors: Edvardsson N. , Juul‐Möller S. , Ömblus R. , Pehrsson K.
Published: June 2003

Abstract. Edvardsson N, Juul‐Möller S, Ömblus R, Pehrsson K (Sahlgrenska University Hospital, Malmö University Hospital, Bristol‐Myers Squibb Bromma; and Karolinska University Hospital; Stockholm, Sweden). Effects of low‐dose warfarin and aspirin versus no treatment on stroke in a medium‐risk patient population with atrial fibrillation. J Intern Med 2003; 254: 95–101.

Objectives. To assess the optimal stroke prevention treatment for patients with atrial fibrillation (AF) and a low–medium risk (≤4%) of stroke.

Design. A total of 668 patients with persistent or permanent AF, without an indication for full dose and with adequate rate control on sotalol, were randomized to warfarin 1.25 mg + aspirin 75 mg daily (W/A, 334 patients) or no anticoagulation (C, 334 patients). The mean follow‐up period was 33 months. The protocol intended to verify a 37% relative risk reduction provided a 4% stroke incidence in the C group.

Results. The stroke incidence was less in the W/A group, although the reduction was not statistically significant (W/A 9.6% versus C 12.3%). Four haemorrhagic strokes were identified, two in each group. Secondary end‐points were transient ischaemic attacks (TIA) (W/A 3.3% versus C 4.5%), all cause mortality (W/A 9.3% versus C 10.8%), cardiovascular morbidity (W/A 17.7% versus C 22.2%) and the combination of stroke + TIA (W/A 11.7% versus C 16.5%). Bleedings were documented in 19 versus four patients (W/A 5.7% versus C 1.2%) (P = 0.003), although none fatal. Sinus rhythm (SR) was recorded occasionally in 68 patients (W/A 9.6% versus C 10.8%). The stroke incidence tended to be higher in those with SR than without, 16.2% versus 10.4%.

Conclusions. Our results were inconclusive, but consistent with a small beneficial effect of W/A for reduction of stroke and major vascular events in AF patients at moderate risk. The low‐dose regiment produced, however, a significantly increased risk of bleedings. Documented SR occasionally recorded may represent a subpopulation that warrants full dose warfarin.
Sleep and endocrinology
Authors: Steiger A.
Published: June 2003

Steiger A (Max Planck Institute of Psychiatry, Munich, Germany). Sleep and endocrinology (Minisymposium). J Intern Med 2003; 254: 13–22.

A bidirectional interaction between sleep electroencephalogram and endocrine activity is well established in various species including humans. Various hormones (peptides and steroids) participate in sleep regulation. A keyrole was shown for the reciprocal interaction between sleep‐promoting growth hormone‐releasing hormone (GHRH) and sleep‐impairing corticotropin‐releasing hormone (CRH). Changes in the GHRH : CRH ratio result in changes of sleep‐endocrine activity. It is thought that the change of this ratio in favour of CRH contributes to aberrances of sleep during ageing and depression (shallow sleep, blunted GH and elevated cortisol). Besides GHRH, ghrelin and galanin enhance slow wave sleep. Somatostatin is another sleep‐impairing factor. Neuropeptide Y acts as a CRH antagonist and induces sleep onset. There are hints that CRH promotes rapid eye movement sleep (REMS). In animals prolactin enhances REMS. In humans vasocactive intestinal polypeptide (VIP) appears to play a role in the temporal organization of sleep as, after VIP, the non‐REMS–REMS cycle decelerated. Cortisol appears to enhance REMS. Finally, gonadal hormones participate in sleep regulation. Oestrogen replacement therapy and CRH‐1 receptor antagonism in depression are beneficial clinical applications of sleep‐endocrine research.
Insomnia, metabolic rate and sleep restoration
Authors: Bonnet M. H. , Arand D. L.
Published: June 2003

Bonnet MH, Arand DL (Wright State University, Kettering Medical Center, and Wallace Kettering Neuroscience Institute, Dayton, OH, USA). Insomnia, metabolic rate and sleep restoration (Minisymposium). J Intern Med 2003; 254:–.

Studies have shown occasional evidence of increased physiological activity in patients with primary insomnia. We hypothesized that metabolic rate, as measured by overall oxygen use (), might be a more general index of increased physiological activity. An initial experiment found elevated both at night and during the day in patients with primary insomnia as compared with matched normal sleepers. A second experiment found significant but more modest increases in in patients with Sleep State Misperception Insomnia [who complain of poor sleep but who had normal sleep by electroencephalographic (EEG) criteria]. In a third experiment, normal young adults were given caffeine 400 mg three times per day (TID) for 1 week as a means of increasing and possibly producing other symptoms of insomnia. Participants developed many symptoms consistent with those seen in patients with primary insomnia (poor sleep, increased latency on the Multiple Sleep Latency Test, increasing fatigue despite physiological activation, and increased anxiety on the Minnesota Multiphasic Personality Inventory (MMPI)). In a final experiment, physiological arousal was again produced by caffeine to determine if sleep with elevated arousal would be less restorative. All subjects (Ss) slept for 3.5 h after being given 400 mg of caffeine. During 41 h of sleep deprivation that followed, there was no significant condition difference for the Multiple Sleep Latency Test or mood measures. The results provided only weak support for the idea that sleep is less restorative after physiological arousal.
Metabolic disturbances in obesity versus sleep apnoea: the importance of visceral obesity and insulin resistance
Authors: Vgontzas A. N. , Bixler E. O. , Chrousos G. P.
Published: June 2003

Abstract.  Vgontzas AN, Bixler EO, Chrousos GP (Penn State College of Medicine, Hershey, PA; National Institutes of Health, Bethesda, MD, USA). Metabolic disturbances in obesity versus sleep apnoea: the importance of visceral obesity and insulin resistance (Minisymposium). J Intern Med 2003; 254:–.

Obstructive sleep apnoea (OSA) is a very prevalent disorder particularly amongst middle‐aged, obese men, although its existence in women as well as in lean individuals is increasingly recognized. Despite the early recognition of the strong association between OSA and obesity, and OSA and cardiovascular problems, sleep apnoea has been treated as a ‘local abnormality’ of the respiratory track rather than as a ‘systemic illness’. In 1997, we first reported that the pro‐inflammatory cytokines interleukin (IL)‐6 and tumour necrosis factor‐α (TNFα) were elevated in patients with disorders of excessive daytime sleepiness (EDS) and proposed that these cytokines were mediators of daytime sleepiness. Also, we reported a positive correlation between IL‐6 or TNFα plasma levels and the body mass index (BMI). In subsequent studies, we showed that IL‐6, TNFα, leptin and insulin levels were elevated in sleep apnoea independently of obesity and that visceral fat, was the primary parameter linked with sleep apnoea. The association of OSA with insulin resistance and diabetes type 2 has been confirmed since then in several epidemiological and clinical studies. Furthermore, our findings that women with polycystic ovary syndrome (PCOS, a condition associated with hyperandrogenism and insulin resistance) were much more likely than controls to have sleep disordered breathing (SDB) and daytime sleepiness support the pathogenetic role of insulin resistance in OSA. Other findings that support the view that sleep apnoea and sleepiness may be manifestations of a serious metabolic disorder, namely the Metabolic or Visceral Obesity Syndrome, include: obesity without sleep apnoea is associated with daytime sleepiness; PCOS and diabetes type 2 are independently associated with EDS after controlling for SDB, obesity and age; and increased prevalence of sleep apnoea in postmenopausal women, with hormonal replacement therapy associated with a significantly reduced risk for OSA.

In conclusion, accumulating evidence provides support to our model of the bi‐directional, feedforward, pernicious association between sleep apnoea, sleepiness, inflammation and insulin resistance, all promoting atherosclerosis and cardiovascular disease.
Sleep as restitution: an introduction
Authors: Åkerstedt T. , Nilsson P. M.
Published: June 2003

Abstract. 

Åkerstedt T, Nilsson PM (Karolinska Institutet, Stockholm, University Hospital, Malmö, Sweden). Sleep as restitution: an introduction (Minisymposium). J Intern Med 2003; 254: 6–12.

This paper summarizes a symposium that has shown that sleep is a state of altered metabolism, and that disturbances and curtailments of sleep have far‐reaching effects on endocrinology, immunology and metabolism, changes that may be linked to disease. As yet, the entire causal chain is weak but there are indications that, in particular, the risk of type 2 diabetes and cardiovascular disease may result from disturbed sleep. It is hypothesized that both insulin resistance and chronic low‐grade inflammation may be involved.
Hydrophobic residues within the predicted N‐terminal amphiphilic α‐helix of a plant mitochondrial targeting presequence play a major role in in vivo import
Authors: Duby Geoffrey , Oufattole Mohammed , Boutry Marc
Published: June 2003

A deletion and mutagenesis study was performed on the mitochondrial presequence of the β‐subunit of the F1‐ATP synthase from Nicotiana plumbaginifolia linked to the green fluorescent protein (GFP). The various constructs were tested in vivo by transient expression in tobacco protoplasts. GFP distribution in transformed cells was analysed in situ by confocal microscopy, and in vitro in subcellular fractions by Western blotting. Despite its being highly conserved in different species, deletion of the C‐terminal region (residues 48–54) of the presequence did not affect mitochondrial import. Deletion of the conserved residues 40–47 and the less conserved intermediate region (residues 18–39) resulted in 60% reduction in GFP import, whereas mutation of conserved residues within these regions had little effect. Further shortening of the presequence progressively reduced import, with the construct retaining the predicted N‐terminal amphiphilic α‐helix (residues 1–12) being unable to mediate mitochondrial import. However, point mutation showed that this last region plays an important role through its basic residues and amphiphilicity, but also through its hydrophobic residues. Replacing Arg4 and Arg5 by alanine residues and shifting the Arg5 and Leu6 (in order to disturb amphiphilicity) resulted in reduction of the presequence import efficiency. The most dramatic effects were seen with single or double mutations of the four Leu residues (positions 5, 6, 10 and 11), which resulted in marked reduction or abolition of GFP import, respectively. We conclude that the N‐terminal helical structure of the presequence is necessary but not sufficient for efficient mitochondrial import, and that its hydrophobic residues play an essential role in in vivo mitochondrial targeting.