bluuebunny/crossref_metadata_2025 huggingface dataset:
Population‐based outcomes after acute antenatal transfer
Authors: Fenton Alan C. , Ainsworth Sean B. , Sturgiss Stephen N.
Published: March 2003

Acute antenatal transfer to specialist centres is an accepted practice but few or no regular data are collected regarding the numbers of transfers performed or subsequent pregnancy outcome. We wished to determine the numbers, and the maternal and fetal outcomes following acute antenatal transfer between consultant obstetric units in the former Northern Region of the UK over a 12‐month period (1 January–31 December 99). This is a geographically defined population in terms of provision of perinatal services. All acute antenatal transfers were notified centrally. Data pertaining to each transfer were collected at the time of transfer. Subsequent maternal and fetal outcomes were determined from patient records and neonatal databases. The regional annual acute antenatal transfer rate was 3.7 per 1000 deliveries. Most were for fetal reasons, although transfer rates varied between hospitals. The decision to transfer was influenced by distance and availability of paediatric staff. Even units that have similar characteristics show considerable variation in their transfer rates. No adverse incidents occurred during transfer and no major changes in maternal management occurred following transfer. Twenty‐four per cent of women remained undelivered following transfer. Women with preterm labour in the absence of ruptured membranes were less likely to deliver than those transferred for other reasons and if they did deliver, their infants were also less likely to need intensive care. We believe audit of acute antenatal transfers should be routinely undertaken. Numbers of transfers might be reduced if delivery and the need for neonatal intensive care could be predicted with greater accuracy. The psychological and financial costs of transfer to women and healthcare providers need to be addressed.
Epidemiological characteristics of retinoblastoma in children attending the Mexican Social Security Institute in Mexico City, 1990–94
Authors: Amozorrutia‐Alegría Víctor , Bravo‐Ortiz Juan Carlos , Vázquez‐Viveros Josefina , Campos‐Campos Laura , Mejía‐Aranguré Manuel , Juárez‐Ocaña Servando , Martínez‐García María del Carmen , Fajardo‐Gutiérrez Arturo
Published: March 2003

The object of this study is to present descriptive epidemiological characteristics of retinoblastoma (Rb) in children aged 0–14 years, seen at the Mexican Social Security Institute hospitals in Mexico City (MC) from 1990 to 1994. This is a retrospective, observational hospital survey. Clinical records of 52 Rb cases were reviewed; 39 were patients who did not reside in MC (non‐residents), and 13 were MC residents. The study period was 1990–94. The male/female ratio (M/F) was 1.6. Average annual incidence (AAI) was estimated by age and sex (rates per 1 000 000). Annual average percentage change (AAPC) in incidence rates was estimated in children from 0 to 14 years. The AAI for MC residents was 3.2; the highest rate being for those <1 year olds (rate of 20.8); AAPC was 6.9% [95% CI –27.5, 57.4]; the highest incidence was for the south‐eastern region of MC residents (rate of 5.9); 13 cases (25%) were diagnosed at stage III or IV, and 11 cases (21.2%) were bilateral. Incidence of Rb is similar to that in developed countries and shows no increasing trend. Patients from communities outside MC are more frequently diagnosed at stages III and IV.
Intestinal mast cell response and mucosal defence against Strongyloides venezuelensis in interleukin‐3‐hyporesponsive mice
Authors: KOBAYASHI  , TSUCHIYA  , HARA  , NAKAHATA  , KUROKAWA  , ISHIWATA  , UCHIYAMA FUKUMI , NAWA
Published: March 2003

Recently several inbred strains of mice were found to be hyporesponsive to Interleukin (IL)‐3 because of a 5‐bp deletion in the intron 7 of the gene that encodes IL‐3 receptor α subunit (IL‐3Rα). Due to this mutation, mast cells were not generated in vitro from bone marrow cells of these mice under the presence of IL‐3. Intestinal mucosal mast cells, of which growth/differentiation is dependent on IL‐3, are important effector cells in immune‐mediated expulsion of intestinal nematodes, Strongyloides spp. In the present study, therefore, we examined intestinal mast cell response and mucosal defence against Strongyloides venezuelensis in IL‐3‐hyporesponsive C58/J and A/J mice. After subcutaneous inoculation with 10 000 infective larvae, C58/J and IL‐3‐responsive C57BL/6 mice showed identical kinetic patterns of daily faecal egg output and intestinal mast cell response. When these mice were infected with 3000 L3 and, five weeks later, they were challenged by intraduodenal implantation of 800 S. venezuelensis adult worms, the timing of logarithmic decline of faecal egg count as well as intestinal mastocytosis was delayed for two days in C58/J mice. Kinetics of intestinal mastocytosis and faecal egg excretion after a primary and challenge infection in A/J mice, another IL‐3‐hyporesponsive strain, were identical with those seen in C58/J mice. These results suggest that intestinal mast cell response and mucosal defence against S. venezuelensis of the mutant mice were almost completely compensated in vivo. Possible mechanisms of induction of intestinal mast cell response in IL‐3Rα‐defective mice are discussed.
Mesenteric lymph node T cells but not splenic T cells maintain their proliferative response to Concanavalin‐A following peroral infection with Toxoplasma gondii
Authors: NEYER LAURI ELLIS , KANG HOIL , REMINGTON JACK S. , SUZUKI YASUHIRO
Published: March 2003

The suppression of T cell responsiveness which occurs after infection with Toxoplasma gondii in mice has been widely studied using spleen cells. Because the natural route of infection with T. gondii is the peroral route, we examined the proliferative responses of mesenteric lymph node (MLN) cells, in addition to spleen cells, to Concanavalin‐A (Con‐A) in mice perorally infected with T. gondii. Proliferative responses of spleen cells were significantly suppressed seven and ten days after infection when compared with spleen cells from uninfected mice (62% and 91% reduction, respectively). In contrast, proliferative responses of MLN cells from these infected mice did not differ from those of normal MLN cells. Since IFN‐γ‐induced reactive nitrogen intermediate (RNI) production has been reported to play a major role in suppression of proliferative responses in spleen cells of infected mice, we compared production of IFN‐γ and RNI by spleen and MLN cells following infection. MLN cells produced as much IFN‐γ as did spleen cells, but produced 70% less nitrite (as a measure of RNI) after Con‐A stimulation. Proliferative responses of MLN cells were suppressed when co‐cultured with spleen cells from infected mice, and addition of an inhibitor of RNI to these co‐culture inhibited this suppression, suggesting that reduced RNI production by MLN cells contributes to their maintenance of higher proliferative responses. These results demonstrated a clear difference in activity of T cells in the MLN and spleen during the acute stage of the infection.
Intestinal and systemic humoral immunological events in the susceptible Balb/C mouse strain after oral administration of Echinococcus multilocularis eggs
Authors: PATER CLOTILDE , MÜLLER VOLKER , HARRAGA SAÏD , LIANCE MARTINE , GODOT VÉRONIQUE , CARBILLET JEAN‐PIERRE , MEILLET DOMINIQUE , RÖMIG THOMAS , VUITTON DOMINIQUE ANGÈLE
Published: March 2003

The aim of the study was to investigate the systemic and, for the first time, the intestinal humoral events in the susceptible Balb/C mouse strain after oral administration of Echinococcus multilocularis eggs. Thirty‐one mice were divided into three groups; W‐2 , W‐8 and control group. Each mouse of the W‐2 and W‐8 groups was orally infected with 1,500 E. multilocularis eggs, two weeks and eight weeks before sacrifice respectively. Control group mice received phosphate buffer saline. Measurement of anti‐E. multilocularis and non‐specific IgG, IgA and IgM, and of a transudation marker, albumin, were performed in serum and intestinal washings by a time‐resolved immunofluorometric assay. These results were complemented by microscopic examination of the intestinal mucosa. This infection model is well‐suited to the study of mucosal immunity during alveolar echinococcosis. It showed a major specific intestinal response in the early stage of the disease whereas the systemic response predominated later in the disease. Histopathological studies and calculation of the relative coefficient of excretion of Ig also confirmed that the presence of the parasite, even during a short period, was responsible for a local immunological and inflammatory response and for a change in mucosal permeability. Mucosal immunity could thus play a role in tolerance induction against E. multilocularis that could be a prerequisite for the subsequent development of the larvae in the liver, and for the occurrence of the parasitic disease, alveolar echinococcosis.
Inhibition of in vitro growth of Plasmodium falciparum field isolates mediated by human antibodies to Pf155/RESA and Pf332
Authors: WÅHLIN FLYG BIRGITTA , SIDDIQUE ABU BAKAR , PERLMANN PETER , ESPOSITO FULVIO , BERZINS KLAVS
Published: March 2003

The capacity of antibodies to interfere with Plasmodium falciparum growth in in vitro cultures is considered to reflect some of their potential protective effects in vivo. Almost all previous analyses of antibody mediated inhibition of parasite growth in vitro were performed with different laboratory strains of P. falciparum. This study was performed to investigate if the long‐term culturing of parasites has any effect on their susceptibility to such growth inhibition. The growth inhibitory effects of human antibodies to the vaccine candidate antigens Pf155/RESA and Pf332 on fresh field isolates from children in Burkina Faso were analysed and compared with their effect on an established laboratory strain of the parasite. Although there was variation in the inhibition titres between different isolates tested against one antibody preparation, the differences in inhibition capacity for the three different antibodies were highly significant. No correlation was found between serum levels of anti‐Pf155/RESA or ‐Pf332 antibodies and sensitivity of the corresponding parasite isolates to antibody mediated growth inhibition.
Antibody response in CD4‐depleted mice after immunization or during early infection with Echinococcus granulosus
Authors: BAZ ADRIANA , RICHIERI ANA , PUGLIA ALEJANDRA , NIETO ALBERTO , DEMATTEIS SYLVIA
Published: March 2003

The aims of this work were to investigate the existence of T‐independent antigens in Echinococcus granulosus protoscoleces and to evaluate the relative contribution of T‐independent stimulation to the overall antibody response in early infection. Mice depleted of CD4+‐cells were immunized with protoscolex somatic antigens (PSA) or infected with E. granulosus protoscoleces (PSC). Results showed that the response of CD4‐depleted immunized mice had the expected characteristics of a T‐independent stimulation and that such T‐independent stimulation was important mainly during primary response. During infection absence of CD4+‐cells affected mainly the secretion of all IgG subclasses with the exception of IgG3 and IgM. To carry out a preliminary isolation of PSC T‐independent antigens we prepared a carbohydrate enriched fraction from protoscolex antigens, using a monoclonal antibody specific for the carbohydrate moiety Galα(1,4)Gal highly expressed in PSC. This fraction was mitogenic for naive mouse splenocytes and was recognized by a high percentage of the specific antibodies secreted by CD4‐depleted immunized or infected mice. In summary, these results suggest that E. granulosus protoscoleces contain immunogenic T‐independent antigens. Primary antibody responses to protoscolex somatic antigens and the production of IgM and IgG3 in early infection would be mainly stimulated by a T‐independent mechanism.
TNF‐α, nitric oxide and IFN‐γ are all critical for development of necrosis in the small intestine and early mortality in genetically susceptible mice infected perorally with Toxoplasma gondii
Authors: LIESENFELD OLIVER , KANG HOIL , PARK DANIEL , NGUYEN THU A. , PARKHE CHANDAN V. , WATANABE HISAMI , ABO TORU , SHER ALAN , REMINGTON JACK S. , SUZUKI YASUHIRO
Published: March 2003

We previously reported that genetic susceptibility of mice to peroral infection with T. gondii is associated with CD4+ T cell‐dependent, interferon (IFN)‐γ‐mediated necrosis of their small intestine. We examined the role of tumour necrosis factor (TNF)‐α and nitric oxide (NO), in addition to IFN‐γ. At 7 days after infection, a marked increase in CD4+ T cells was observed in lamina propria mononuclear cells (LPC) of the small intestine as compared with normal mice, and significantly greater amounts of mRNA for IFN‐γ, TNF‐α, and inducible NO synthase (iNOS) were detected in LPC of the small intestine of infected than uninfected animals. Treatment of infected mice with anti‐TNF‐α monoclonal antibody (mAb) or the iNOS inhibitor, aminoguanidine, prevented necrosis and prolonged time to death. Infected iNOS‐targeted mutant mice did not develop the disease whereas infected, control mice did. Treatment with anti‐TNF‐α mAb did not affect the expression of IFN‐γ in the LPC but inhibited expression of iNOS in the infected mice, indicating the role of TNF‐α in the induction of iNOS. These results suggest that NO induced by a combination of IFN‐γ and TNF‐α through activation of iNOS is a critical mediator of intestinal pathology and contributes to early mortality in genetically susceptible mice.
Specificity in signal transduction among glycosylphosphatidylinositols of Plasmodium falciparum, Trypanosoma brucei, Trypanosoma cruzi and Leishmania spp.
Authors: Tachado Souvenir D. , Mazhari‐Tabrizi Ramin , Schofield Louis
Published: March 2003

Glycosylphosphatidylinositols (GPIs) and related glycoconjugates of parasite origin have been shown to regulate both the innate and acquired immune systems of the host. This is achieved through the activation of novel GPI‐dependent signalling pathways in macrophages, lymphocytes and other cell types. Parasite GPIs impart at least two distinct signals to host cells through the structurally distinct inositolphosphoglycan (IPG) and fatty acid domains. Binding of IPG to as yet uncharacterized cell surface receptor(s) leads to activation of src‐family protein tyrosine kinases: depending upon structure, GPI‐derived fatty acids can either activate or antagonize protein kinase C, and may enter the sphingo‐myelinase pathway. The degree of fatty acid saturation may also contribute to signalling activity. Thus, variation in structure of parasite GPIs imparts different properties of signal transduction upon this class of glycolipid. The divergent activities of GPIs from various protozoal taxa reflect global aspects of the host/parasite relationship, suggesting that GPI signalling is a central determinant of disease in malaria, leishmaniasis and both American and African trypanosomiases.
Anti‐schistosome antibody responses in children coinfected with malaria
Authors: Mutapi  , Ndhlovu  , Hagan  , Woolhouse
Published: March 2003

People residing in schistosome endemic areas are often infected with other parasites. The interaction of the parasites in the host has important implications in the development of acquired immunity to schistosomiasis, and schistosome immuno‐epidemiology. An analysis of specific anti‐schistosome egg responses in children coinfected with schistosomiasis and malaria shows that malaria positive children produce significantly more anti‐schistosome IgE and IgG3 than schistosome infected children who are negative for malaria.
A calreticulin‐like molecule from the human hookworm Necator americanus interacts with C1q and the cytoplasmic signalling domains of some integrins
Authors: Kasper Grit , Brown Alan , Eberl Matthias , Vallar Laurent , Kieffer Nelly , Berry Colin , Girdwood Karen , Eggleton Paul , Quinnell Rupert , Pritchard David I.
Published: March 2003

Calreticulin was recently identified as a hookworm Necator americanus allergen, implying secretion, and contact with cells of the immune system, or significant worm attrition in the tissues of the host. As human calreticulin has been shown to bind to and neutralize the haemolytic activity of the complement component C1q, and to be putatively involved in integrin‐mediated intracellular signalling events in platelets, it was of interest to determine whether a calreticulin from a successful nematode parasite of humans, with known immune modulatory and antihaemostatic properties, exhibited a capacity to interfere with complement activation and to interact with integrin domains associated with cell signalling in platelets and other leucocytes. We can now report that recombinant calreticulin failed to demonstrate significant calcium binding capacity, which is a hallmark of calreticulins in general and may indicate inappropriate folding following expression in a prokaryote. Nevertheless, recombinant calreticulin retained sufficient molecular architecture to bind to, and inhibit the haemolytic capacity of, human C1q. Furthermore, recombinant calreticulin reacted in surface plasmon resonance analysis (SPR) with peptides corresponding to cytoplasmic signalling domains of the integrins αIIb and α5, in a calcium independent manner. SPR was also used to ratify the specificity of a polyclonal antibody to hookworm calreticulin, which was then used to assess the stage specificity of expression of the native molecule (in comparison with reverse transcriptase‐polymerase chain reaction), to indicate its apparent secretion, and to purify native calreticulin from worm extracts by affinity chromatography. This development will allow the functional tests described above to be repeated for native calreticulin, to ascertain its role in the host–parasite relationship.
Transforming growth factor‐β suppresses interferon‐γ‐induced toxoplasmastatic activity in murine macrophages by inhibition of tumour necrosis factor‐α production
Authors: Langermans J.A.M. , Nibbering P.H. , Van Vuren‐Van Der Hulst M.E.B. , Van Furth R.
Published: March 2003

Activation of macrophages plays an important role in the host resistance against intracellular pathogens. Various mechanisms are employed to control the activation processes and limit tissue damage by factors produced by activated macrophages. One of these mechanisms is the production of macrophage‐deactivating cytokines, such as tumour growth factor (TGF)‐β. The present study concerns the effects of TGF‐β on interferon (IFN)‐γ‐induced activation of murine macrophages with respect to induction of toxoplasmastatic activity, and production of tumour necrosis factor (TNF)‐α, prostaglandin E2 (PGE2) and reactive nitrogen intermediates (RNI). IFN‐γ activation of macrophages resulted in inhibition of T.  gondii proliferation [mean fold increase (FI) = 1·8, control mean FI = 7·0]; polymyxin B had no effect on this activation. The IFN‐γ‐induced toxoplasmastatic activity of macrophages was inhibited by TGF‐β (mean FI = 6·3), which was also found for the IFN‐γ‐induced production of TNF‐α, RNI and PGE2 by macrophages. We found that PGE2, which has macrophage deactivating properties, was not involved in the inhibition of macrophage activation by TGF‐β. The deactivating activities of TGF‐β on the IFN‐γ‐induced toxoplasmastatic activity and production of RNI are mediated by inhibition of production of TNF‐α. Addition of exogenous TNF‐α during the incubation of macrophages with IFN‐γ and TGF‐β abrogated the deactivating activity of TGF‐β. In sum, the results demonstrate that inhibition of TNF‐α production is a key factor in the TGF‐β‐induced suppression of macrophage activation with respect to toxoplasmastatic activity and RNI production.
Leishmania donovani‐induced macrophages cyclooxygenase‐2 and prostaglandin E2 synthesis
Authors: Matte Claudine , Maion Grazia , Mourad Walid , Olivier Martin
Published: March 2003

Prostaglandin E2 (PGE2) secretion during Leishmania infection has been reported. However, the signalling mechanisms mediating this response are not well understood. Since cyclooxygenase‐2 (COX‐2) and cytosolic phospholipase A2 (cPLA2) are involved in PGE2 synthesis in response to various stimuli, the implication of these enzymes was evaluated in Leishmania‐infected phorbol myristate acetate‐differentiated U937 human monocytic cell line. Time‐course experiments showed that PGE2 synthesis increased significantly in parallel with COX‐2 expression when cells were incubated in the presence of Leishmania donovani promastigotes or lipopolysaccharides (LPS). Increase in cPLA2 mRNA expression was only detected when cells were stimulated with LPS. Indomethacin, genistein, and H7, which are antagonists of COX‐2, protein tyrosine kinase (PTK) and protein kinase C (PKC), respectively, inhibited PGE2 production induced by L. donovani and LPS. However, only H7 inhibited COX‐2 mRNA synthesis, and there was a significant correlation between PGE2 inhibition and reduced COX‐2 expression. Collectively, our results indicate that infection of U937 by L. donovani leads to the generation of PGE2 in part through a PKC‐dependent signalling pathway involving COX‐2 expression. They further reveal that PTK‐dependent events are necessary for Leishmania‐induced PGE2 generation, but not for COX‐2 expression. A better understanding of the mechanisms by which Leishmania can induce PGE2 production could provide insight into the pathophysiology of leishmaniasis and may help to improve therapeutic approaches.
Antibody responses in onchocerciasis as a function of age and infection intensity
Authors: Faulkner Helen , Gardon Jacques , Kamgno Joseph , Enyong Peter , Boussinesq Michel , Bradley Janette E.
Published: March 2003

Onchocerciasis is caused by the filarial nematode Onchocerca volvulus and is a major public health problem in West and Central Africa. With only partial and long‐term treatment currently available, there is a need to develop a suitable vaccine. We analysed the antibody response to infective L3 larvae because this stage is thought to be associated with host protective immunity. In addition, we have related our findings to the age, gender and current infection intensity of our participants: variables that may significantly influence antibody production. Interestingly, whilst 90% of our study group were seropositive for adult specific immunoglobulin (Ig)E, only 23% produced L3 specific IgE. This is in contrast to IgG4 where seropositivity was comparable at 96% and 92%, respectively. Furthermore, IgG levels were significantly affected by age and the intensity of infection but unaffected by host gender. This finding is independent for the IgG subclass (IgG1, IgG2, IgG3 and IgG4) and its specificity (L3 versus adult antigen). In summary, we show that L3 larvae induce little specific IgE and the antibody response shows a different isotype balance than that against adult antigens. Both host and parasite variables can influence antibody production in this disease.
Temporal distribution of distinct mast cell phenotypes during intestinal schistosomiasis in mice
Authors: De Jonge Frederik , Van Nassauw Luc , Van Meir Frans , Miller Hugh R. P. , Van Marck Eric , Timmermans Jean‐Pierre
Published: March 2003

Mastocytosis is a common feature of helminth infection in most host species. We examined the temporal distribution and phenotype of mast cells during intestinal schistosomiasis in mice, using antibodies directed against histamine, a general mast cell marker, against mouse mast cell protease‐1 (MMCP‐1), a mucosal mast cell (MMC) marker, and against tryptase, a predominantly connective tissue mast cell (CTMC) marker. Ileal paraffin and/or cryosections of control, 8‐ and 15‐week‐infected mice were quantitatively analysed. In the intestinal wall of non‐ and unisexual infected mice, a few dispersed mast cells were detected. In infected mice, a transient increase of mast cells in the mucosa and a gradual increase in the outer muscle layer were observed. MMCP‐1 expressing MMCs were predominantly present in the mucosa during the acute phase [8 weeks postinfection (p.i.)], while tryptase and histamine immunoreactivity demonstrated that two subsets of CTMCs were predominantly present in the outer muscle layer at 15 weeks p.i. (chronic phase). In conclusion, these results reveal that, in mice, both MMCs and CTMCs are involved in the inflammatory response during schistosomiasis. The recruitment of each mast cell population is time‐dependent and occurs at different locations. These data suggest that mastocytosis is associated with motility‐related gastrointestinal symptoms and egg excretion.
Toxocara canis antigens stimulate the production of nitric oxide and prostaglandin E2 by rat alveolar macrophages
Authors: Espinoza Elsa , Muro Antonio , Martín Manuel‐Mario Sánchez , Casanueva Patricia , Pérez‐Arellano José Luis
Published: March 2003

The effect of four Toxocara canis antigens on nitric oxide (NO) and prostaglandin E2 (PGE2) synthesis was studied in vitro using rat alveolar macrophages. Somatic and excretory/secretory T. canis antigens prepared from adult worms and LII larvae were incubated with rat alveolar macrophages obtained by bronchoalveolar lavage at concentrations of 0·1–50 µg/ml. Both excretory/secretory adult antigen (ESA) and somatic LII antigen (SLII) stimulate the release of nitrites by alveolar macrophages. This effect was specific (inhibited by l‐NAME and l‐canavanine) and dose‐dependent; 30 µg and 10 µg being the most effective concentrations of ESA and SLII, respectively. Western blot and reverse transcriptase‐polymerase chain reaction analyses revealed that ESA antigen stimulates the production of NO at transcriptional level. T. canis ESA also stimulated macrophages to produce PGE2 at transcriptional level. The addition of l‐canavanine decreased the release of PGE2 significantly, which suggests that NO mediates the production of this prostaglandin. These results indicate that T. canis can stimulate the release of vasodilatory mediators by macrophages of the host.
Mechanisms of apoptosis in murine fibroblasts by two intracellular protozoan parasites,Toxoplasma gondiiandNeospora caninum
Authors: Nishikawa Yoshifumi , Makala Levi , Otsuka Haruki , Mikami Takeshi , Nagasawa Hideyuki
Published: March 2003

Studies to clarify the mechanisms of apoptosis in host cells, A31 (BALB/3T3 clone A31 fibroblasts), caused by two intracellular protozoan parasites,Toxoplasma gondiiandNeospora caninum, were carried out in anin vitrosystem. The viability ofN. caninum‐infected cells was significantly reduced following treatment with mouse interferon (IFN)‐γ. By contrast, mouse IFN‐γ treatment had no significant effect on the induction of apoptosis inT. gondii‐infected cells. Apoptosis ofN. caninum‐infected and mouse IFN‐γ‐treated cells was shown to be associated with increased DNA fragmentation, and increased caspase‐3 and ‐8 activity, and the administration of caspase‐3 and ‐8 inhibitors inhibited cell death. FasL expression was clearly induced byN. caninum‐infection and IFN‐γ treatment compared to theT. gondii‐infected cells and the uninfected control with or without IFN‐γ treatment. The reduction in host‐cell viability was prevented with the addition of antimouse FasL monoclonal antibody (mAb). Moreover, TUNEL analyses indicated that apoptosis was induced by the treatment with Fas mAb in bothT. gondiiandN. caninum‐infected cells. These results suggest that the Fas/FasL pathway may play a crucial role in the induction of apoptosis inN. caninum‐ andT. gondii‐infected cells mediated by IFN‐γ.
Diminished immunopathology in Schistosoma mansoni infection following intranasal administration of cholera toxin B‐immunodominant peptide conjugate correlates with enhanced transforming growth factor‐β production by CD4 T cells
Authors: Hernandez Hector J. , Rutitzky Laura I. , Lebens Mike , Holmgren Jan , Stadecker Miguel J.
Published: March 2003

In Schistosoma mansoni infection, CD4 T cells specific for parasite egg antigens mediate perioval granuloma formation in the liver and intestines. Mice of the CBA strain develop a severe form of disease and a significant proportion of their CD4 T cell response is directed against the major egg antigen Sm‐p40 and its immunodominant T cell epitope peptide 234–246. Here, we show that intranasal (i.n.) treatment of infected CBA mice with a fusion protein of the cholera toxin B subunit (CTB) with peptide 234–246 (CTB::pep) results in significant down‐modulation of hepatic granulomatous inflammation and fibrosis. Moreover, egg antigen‐stimulated dispersed hepatic granuloma cells, as well as mesenteric lymph node CD4 T cells from the CTB::pep‐treated mice, produced significantly more transforming growth factor (TGF)‐β than that produced by treated or untreated controls. The data demonstrate that i.n. administration of a single immunodominant peptide conjugated to CTB can lead to down‐regulation of the hepatic immunopathology associated with schistosomiasis, and that this down‐regulation is, at least in part, mediated by TGF‐β.
Aggregation in the haematophagous bug Triatoma infestans: a novel assembling factor
Authors: FIGUEIRAS A. N. LORENZO , LAZZARI C. R.
Published: March 2003

Abstract. The response of Triatoma infestans (Klug) to odours left behind by walking insects was analysed. The insects aggregated on papers marked with putative chemical footprints in the absence of other assembling chemical signals. Contact of the receptor insect with the treated surface was necessary to elicit the response because the signal was not able to attract insects, only to arrest them on marked surfaces. These requirements contrast with other chemical aggregation signals of triatomines that attract the insect and involve olfactory responses. By washing the cuticle of the insects with hexane and impregnating papers with the extract, a response was evoked in test insects similar to that elicited by papers on which insects had walked. The biological role of this novel aggregation factor is discussed in relation to other assembling signals of different origin.
Plant acids modulate chemosensory responses in Manduca sexta larvae
Authors: BERNAYS E. A. , GLENDINNING J. I. , CHAPMAN R. F.
Published: March 2003

Abstract.The effects of three plant acids on the gustatory response of Manduca sexta larvae were examined. Two different categories of response were recorded in the styloconic sensilla of different individuals in the presence of salt: the gustatory response to salt was reduced especially at the lower pHs; the deterrent cell fired particularly at the lower pHs. In some individuals neither response was seen except at the lowest pHs. Additional experiments indicated that the effect was due to pH and not to specific effects of any of the acids. Ascorbic acid was tested with the nutrient carbohydrates glucose and inositol, and was found consistently to reduce the gustatory responses to these compounds. The data indicate that plant acids at natural concentrations could influence food acceptability.
Responses of olfactory receptor neurones to behaviourally important odours in gregarious and solitarious desert locust,Schistocerca gregaria
Authors: Ochieng′ Samuel A. , Hansson BilL. S.
Published: March 2003

Abstract.Recordings from antennal olfactory receptor neurones in young adult Schistocerca gregaria Forskål (Orthoptera: Acrididae) showed that behaviourally important odours are detected by receptor neurones present in morphologically identifiable sensillum types. Both nymph‐ and adult‐produced aggregation pheromones activate receptor neurones housed in sensilla basiconica. The receptor neurones in this sensillum type in solitary‐reared locusts display a higher sensitivity to aggregation pheromones and to some other behaviourally relevant odours than the same type of neurones in gregarious locusts. Receptor neurones present in sensilla coeloconica respond to green leaf odours, organic acids, and nymphal odours but are inhibited by mature adult‐produced aggregation pheromones. Receptor neurones housed in sensilla trichodea respond to a possible sex pheromone. No phase differences were found in the response of coeloconic‐ or trichoid‐associated receptor neurones.
Semiochemical and physical stimuli involved in host recognition by Telenomus podisi (Hymenoptera: Scelionidae) toward Euschistus heros (Heteroptera: Pentatomidae)
Authors: Borges M. , Costa M. L. M. , Sujii E. R. , Cavalcanti M. das G. , Redígolo G. F. , Resck I. S. , Vilela E. F.
Published: March 2003

The egg parasitoid, Telenomus podisi, was shown to recognize its host, Euschistus heros, through both chemical and physical cues. These were determined in short‐range bioassays. The cues comprised fertile and infertile host eggs, egg extracts, crude extracts of adult males and females and successive dilutions of the synthetic racemic mixture of methyl 2,6,10‐trimethyltridecanoate, a male‐produced pheromone of E. heros.

Some of the treatments used induced a selection process in T. podisi, through host recognition behaviour, indicating a consistent response of this species to E. heros. The possibility that some of these compounds could be exploited as long‐range kairomones, by T. podisi, is discussed.

Using GC analysis, an unidentified compound (Rt 24.8 min), possibly from the egg adhesive material, was detected from E. heros egg extracts. Its retention time compared to the methyl 2,6,10‐trimethyltridecanoate showed a lower volatility, suggesting that the egg adhesive may act as a short‐range kairomone.

Physical cues appeared to be an important component in the host selection process by T. podisi. The parasitoid discriminated infertile eggs which are differently shaped and smaller than fertile eggs.
Effects of dietary precursors to biogenic amines on the behavioural response from groups of caged worker honey bees (Apis mellifera) to the alarm pheromone component isopentyl acetate
Authors: Harris Jeffrey W. , Woodring Joseph
Published: March 2003

The sound or ‘buzzing response’ from groups of fifteen worker honey bees, Apis mellifera L., to the presentation of isopentyl acetate, an alarm pheromone component, was recorded through a microphone connected via a digital–analogue converter into a computer. The effects of ingested biogenic amine precursors 5‐hydroxytryptophan, L‐DOPA and tryptophan were tested on three variables measurable from the sound traces: onset of the buzzing response after presentation of the pheromone stimulus, the duration of the buzzing event, and the maximal sound frequency produced during the buzzing event. Bees fed high doses of 5‐hydroxytrytophan were found to react significantly more slowly and with a significantly lower maximum frequency than bees that were only fed sucrose controls. Bees fed DOPA were no different from controls for any of the variables measured, and bees fed tryptophan were so hyperactive that reliable responses to the presentation of alarm pheromone could not be made. Finally, the brains of worker bees fed these different precursors were examined for content of various neurochemicals. Bees fed 5‐hydroxytryptophan were found to have dose‐dependent elevations of both 5‐hydroxytryptophan and serotonin within their brains. Bees fed tryptophan were found to have dose‐dependent elevations of tryptophan and kynurenine in the brain but no change in brain serotonin. Bees fed DOPA had dose‐dependent increases in DOPA and dopamine levels within their brains. These results suggest that the hyperactive condition results from kynurenine metabolism, and the reduced response to alarm pheromone is related to serotonin metabolism.
Factors affecting behavioural responses to visual stimuli in the tomato fruit fly, Neoceratitis cyanescens
Authors: Brevault T. , Quilici S.
Published: March 2003

Responses of Neoceratitis cyanescens (Bezzi) (Diptera: Tephritidae) females to visual stimuli were studied in a laboratory flight chamber. A bright orange sphere was used to investigate the effects of age, mating status and time of day on their responses. In no‐choice assays, four parameters were considered: mean time before leaving the release vial, percentage of flies that visited the sphere, mean number of flights and mean time before landing on the sphere. Naive mated females first became strongly responsive to the orange sphere 6 days post‐adult emergence (> 40%). The percentage of females that visited the sphere increased significantly with egg load. There were no significant differences in behavioural responses between virgin and mated mature females. In a choice situation between a yellow and an orange sphere, starved females displayed a greater propensity than well‐fed females to land on the yellow sphere. Mature females were more responsive to the orange sphere when tested in the afternoon than earlier in the day. In a no‐choice situation, females visited the yellow sphere as often as the orange sphere. However, the mean delay before landing was significantly greater for the yellow sphere. The results emphasize the importance of physiological condition on responses of N. cyanescens females to host‐simulating visual stimuli.
Expression of a costly, plastic secondary sexual trait is correlated with age and condition in a damselfly with two male morphs
Authors: Hooper Rowan E. , Tsubaki Yoshitaka , Siva‐Jothy Michael T.
Published: March 2003

Males of the damselfly Mnais costalis Selys (Odonata: Calopterygidae) are morphologically and behaviourally polymorphic, typically existing as clear‐winged non‐territorial ‘sneaks’ and orange‐winged territorial ‘fighters’. The amount of orange pigment in the wing, as measured with a chromameter, varied between individuals, and decreased as the reproductive season progressed. Young individuals maintained in the laboratory on high or low nutrient diets differed in the amount of pigment that developed in the wing. Males in the high nutrient group developed darker wings faster than those in the low nutrient group. Young adults of both sexes and morphs were fed 14C‐radiolabelled tryptophan or tyrosine (precursors of the pigments ommochrome and melanin, respectively). Ommochrome was restricted to the pseudopterostigma of the males of both morphs and was not present in females. The presence of tyrosine in the wing cells of orange males, but not of clear males, indicated that the orange pigment is at least partly constituted from melanin. These data show that at least some pigment levels must be maintained continuously in the wings of orange males, and that maintenance is costly as it is compromised at low nutrient levels.
The biosynthesis of Juvenile Hormone, its degradation and titres in females of the true armyworm: a comparison of migratory and non‐migratory populations
Authors: McNeil Jeremy N. , Miller David , Laforge MarlÈne , Cusson Michel
Published: March 2003

In a previous study [McNeil et al. (1996)
Archives of Insect Biochemistry and Physiology, 32, 575–584], patterns of sexual maturation and Juvenile Hormone (JH) biosynthesis were compared in virgin females from migratory (North American) and non‐migratory (Azorean) populations of the true armyworm moth, Pseudaletia unipuncta Haworth (Lepidoptera: Noctuidae). Sexual maturation occurred at a significantly earlier age after emergence in the non‐migrant population, and the rates of biosynthesis of JH in vitro suggested that lower titres of JH may be required to initiate the onset of calling behaviour (pheromone emission) and ovarian development in Azorean females. To examine the physiological differences in the reproductive biology of migratory and non‐migratory populations in greater detail, the haemolymph titres of JH and JH esterase activity were compared in virgin females as a function of age. In addition, the effects of mating on JH biosynthesis in vitro, JH titres, JH esterase activity and egg production were measured in the two populations. As expected, JH titres rose more rapidly after emergence in Azorean females than in their North American counterparts but, contrary to our prediction, the maximum levels were also higher in the non‐migrant population. Activity of JH esterase was much higher in Azorean females on the day of emergence. However, by the second day both populations had similar activity levels (about 17 nmol JH/min/ml) and exhibited a similar age‐related decline in subsequent days.

Mating did not affect the rate of JH biosynthesis in vitro but resulted in a significant increase in the titres of JH in the haemolymph of both populations. The maximum titre (a five‐fold increase) occurred within 24 h of mating in Azorean females. In North American individuals the increase was greater (seven‐fold) but did not occur until 48 h after mating. No difference in the activity of JH esterase was observed between mated and virgin North American females. By contrast, while there was an age‐related decline in the activity of JH esterase in mated Azorean females, as seen in both North American groups, activity levels in virgin females remained constant with age. In all females, mating resulted in a significant increase in egg production within 24 h.

The Azores is a volcanic archipelago, so these non‐migratory populations were probably founded by immigrants originating from migratory continental populations. It is clear from our results that the change from a life history that includes migration to a non‐migratory one involved more than just a temporal shift in the timing of the production of JH. Furthermore, the interpopulation differences in titres of JH and mating‐induced changes reported here cannot be fully explained by the observed differences in the patterns of activity of JH esterase and JH biosynthesis in vitro.
Diapausing pupae of the flesh fly Sarcophaga crassipalpis (Diptera: Sarcophagidae) are more resistant to inoculative freezing than non‐diapausing pupae
Authors: Kelty Jonathan D. , Jr Richard E. Lee
Published: March 2003

The resistance of diapausing (overwintering) and non‐diapausing (summer) Sarcophaga crassipalpis (Diptera: Sarcophagidae) pupae to inoculative freezing was examined. Although both types of pupae resisted inoculative freezing after 24‐h submergence in water, diapausing pupae were overall significantly more resistant than non‐diapausing pupae. Exposing the thin pupal cuticle by removing the ends of the puparial case eliminated the capacity of both pupal types to resist inoculative freezing, indicating that resistance to inoculative freezing resides with the puparium. Pupae submerged in surfactant solution were significantly less resistant to inoculative freezing than those submerged in water. Furthermore, the puparial water content of pupae submerged in surfactant solution was significantly greater than that of puparia from pupae submerged in water. Surfactant may have promoted inoculative freezing by facilitating the spread of water over the surface of and into the puparium, thereby creating bridges between external ice and pupal body fluids. Extracting puparial surface lipids with chloroform/methanol (2 : 1, v:v) decreased the resistance of non‐diapausing pupae to inoculative freezing but did not significantly affect that of diapausing pupae. This finding indicates that the puparium of diapausing pupae contains protection against inoculative freezing separate from its surface lipids. This barrier may be important in protecting the freezing‐intolerant overwintering pupae against inoculative freezing within their soil hibernaculum.
Habituation of sexual response in male Heliothis moths
Authors: Daly Kevin C. , FigUeredo Aurelio JosÉ
Published: March 2003

It has been generally hypothesized that habituation mediates the effects of pheromone‐based disruption strategies used in the management of moth pests. The current study demonstrates that pheromone‐mediated sexual response in the tobacco budworm moth, Heliothis virescens (F.) (Lepidoptera: Noctuidae), can in fact be modulated by conditions consistent with the production of habituation. An ethogram was used to measure response strength in a wind tunnel experiment where male moths were allowed to respond freely to one of two different blends of female pheromone in 16 trials over 4 days. Post‐test measures were collected to investigate stimulus specificity and long‐term effects. In conditions appropriate to the formation of habituation, habituation will develop and disrupt male sexual response to female sex pheromone. Males repeatedly exposed to plumes of synthetic pheromone blends display a habituated response lasting up to 96 h. Habituation rate and spontaneous recovery of response strength are greater with less intense stimuli. Additionally, males habituated to one blend express no habituation of sexual response when exposed to a different blend. This indicates a high degree of stimulus specificity, which could facilitate outbreeding, and that moths attend to the configuration of the pheromone blend, not simply to its elements.
A taste receptor neurone dedicated to the perception of pyrrolizidine alkaloids in the medial galeal sensillum of two polyphagous arctiid caterpillars
Authors: Bernays E. A. , Chapman R. F. , Hartmann T.
Published: March 2003

It is shown that pyrrolizidine alkaloids are phagostimulants for the caterpillars of two polyphagous arctiid caterpillars, Estigmene acrea and Grammia geneura. The caterpillars will also eat dry glass‐fibre discs containing only pyrrolizidine alkaloid − an example of pharmacophagy. The tip‐recording technique is used to demonstrate that each species has a neurone in the medial galeal styloconic taste sensillum responding to pyrrolizidine alkaloids, although the species differ in their sensitivities. This neurone responds to at least four different pyrrolizidine alkaloids and their N‐oxides, and experiments indicate that it is dedicated to perception of these compounds. The sensory response is phasic–tonic and during the tonic phase remains unchanged for at least 500 ms, resembling the type of response often seen in neurones that are sensitive to plant secondary compounds producing deterrent effects.
In vitro effect of formaldehyde on Douglas fir pollen
Authors: Shirazi A. M. , Muir P. S.
Published: March 2003

Formaldehyde (HCHO) concentrations of up to 479 mmol m–3 have been reported in urban fogwater, yet little is known about the phytotoxicity of HCHO at such concentrations. We report that formaldehyde at target concentrations of 300, 600, 900 and 1200mmol m–3 reduced germination of Douglas fir [Pseudotsuga menziesii (Mirbel) Franco.] pollen in vitro. Formaldehyde concentrations and pH in media containing pollen decreased over 25 h. These effects were not seen with heat‐killed pollen nor with media lacking pollen, which may suggest uptake or detoxification by live pollen. Stress was indicated by ion leakage from pollen, which increased within 20 h in all HCHO treatments. Reduced pollen viability was indicated by TTC staining of pollen, which decreased after HCHO treatment.