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PubMed1986

[Trichinella spiralis as a teacher or the parasite-host relationship between a threadworm and an institute].

The present paper provides a review of activities of the National Institute of Public Health in the field of studies on Trichinella spiralis in man and animals. The development of a system of (immune) surveillance of infections due to Trichinella in pigs has been central since the early sixties. Both the fluorescent antibody technique introduced in 1967 and the enzyme-linked immunosorbent assay (ELISA) published in 1974 are examples of these efforts. The method was standardised and, specifically, the ELISA method was mechanized. Comparative studies were done as part of the activities of the EEC working party concerned with trichinosis. The two methods were officially accepted by the EEC. Studies in the slaughter-house as well as in the piggeries (so-called 'in process control') are possible on the basis of the ELISA technique, in which method interest is also being taken in the United States today. Conceivably, industry in Europe will also become interested in the principles of good manufacturing practice, in which certification of slaughtered animals, based on negative results of ELISA studies (without any further inspection in the slaughter-house) will be possible in theory. In addition to the object directly aimed at, i.e. improvement of the method of detection in pigs, designed to prevent human trichinosis, studies on the parasite Trichinella spiralis centered, among other things, on closer examination of the immune response and effector mechanisms in regard to this nematode infection, in which particularly studies on the role of so-called intestinal mast cells produced interesting new views on the subject of (immunological) regulation.

Academies and Institutes↗
PubMed2002

Role of STAT6 and mast cells in IL-4- and IL-13-induced alterations in murine intestinal epithelial cell function.

Gastrointestinal nematode infections generally invoke a type 2 cytokine response, characterized by the production of IL-4, IL-5, IL-9, and IL-13. Among these cytokines, IL-4 and IL-13 exhibit a functional overlap that can be explained by the sharing of a common receptor or receptor component (IL-4Ralpha). Binding of IL-4 by either the type 1 or 2 IL-4R, or of IL-13 by the type 2 IL-4R, initiates Jak-dependent tyrosine phosphorylation of the IL-4Ralpha-chain and the transcription factor, STAT6. In the present study, we investigated: 1) whether IL-13 has effects on intestinal epithelial cells similar to those observed with IL-4, and 2) whether the effects of IL-4 and IL-13 depend on STAT6 signaling and/or mast cells. BALB/c, STAT6(-/-), and mast cell-deficient W/W(v) mice or their +/+ littermates were treated with a long-lasting formulation of recombinant mouse IL-4 (IL-4C) or with IL-13 for seven days. Segments of jejunum were mounted in Ussing chambers to measure mucosal permeability; chloride secretion in response to PGE(2), histamine, 5-hydroxytryptamine, or acetylcholine; and Na(+)-linked glucose absorption. IL-4C and IL-13 increased mucosal permeability, decreased glucose absorption, and decreased chloride secretion in response to 5-hydroxytryptamine. These effects were dependent on STAT6 signaling. Responses to PGE(2) and histamine, which were dependent on mast cells and STAT6, were enhanced by IL-4C, but not by IL-13. The effects of IL-4 and IL-13 on intestinal epithelial cell function may play a critical role in host protection against gastrointestinal nematodes.

Animals↗
PubMed1996

The development of protective immunity against gastrointestinal nematode and lungworm infections after use of an ivermectin bolus in first-year grazing calves.

Interactions between treatment with an ivermectin bolus at turnout and immunity to bovine parasitic gastroenteritis and bronchitis were examined. Immunity related parameters, i.e. development of clinical disease, parasite development and stimulation of parasite specific antibodies were examined for two grazing seasons and compared with untreated second season cattle (immune control) and untreated parasite naive cattle (nonimmune control). With respect to gastrointestinal nematodes, clinical condition, body weight development, faecal egg counts and pepsinogen concentrations of the bolus treated animals were not significantly different from the respective values of untreated immune cattle, showing a considerable degree of resistance in both groups compared to the parasite naive cattle. With respect to lungworms, untreated immune cattle were protected against clinical disease, but two of eight animals shed larvae again. Bolus treated animals transiently showed mild clinical symptoms and six of seven animals shed low numbers of larvae again, whereas all parasite naive cattle shed high numbers of lungworm larvae and showed signs of disease during the whole grazing season. In spite of the effective treatment with an ivermectin bolus during the first year a considerable resistance to gastrointestinal nematode and lungworm infection was present in the second grazing season.

Animals↗
PubMedDate not supplied

[Phospholipid and fatty acid content of the blood of sheep infected with the nematode Dictyocaulus filaria].

The results of analysis of phospholipids (PL) and fatty acid content in the blood of sheep infected with the nematodes Dictyocaulus filaria are displayed. A significant increase of lysophosphatidylcholine and arachidonic acid as well as a decrease of docozagexaenic acid in PL of infected sheep have been recorded. That points out to structural and functional disorders of cellular membranes during the infection. These disorder could be used as a metabolic criterion to estimate the relationships within the host-parasite system examined.

Animals↗
PubMed1995

Immunoprinting reveals different genetic bases for (auto)immuno diseases.

The genetic basis of complex (auto)immune diseases has been studied for an ovine nematode infection, human rheumatoid arthritis (RA), early onset pauciarticular arthritis (EOPA) and multiple sclerosis (MS). Immunoprinting combines the powerful simplicity of polymerase chain reaction (PCR)-based amplification of discrete, highly informative microsatellite loci with the principle of genetic associations. This approach has allowed us to define novel genetic risk factors in adult RA patient categories whereas EOPA forms in juveniles display other prominent genetic contributions. Differentially regulated tumor necrosis factor (TNF) expression may lead to a better understanding of the causal pathogenesis of EOPA while T cell receptor (TCR) gene polymorphisms appear crucial for RA manifestations in certain patient groups. Statistically significant marker associations have still to be defined for MS in larger panels of patient and control cohorts. The clinical course of the disease will probably have to be taken into account when associations with lymphokine levels are evaluated. In essence a convoluted myriad of negative and a few positive disease association data have been generated efficiently by immunoprinting. As expected, the interrelationships are truly complicated between the polymorphic genetic instances predisposing to autoimmune disease. Nevertheless, risk factors may be defined on an individualized basis by indirect gene diagnosis revealing predispositions and providing a more solid basis for differential diagnosis and treatment.

Adult↗
PubMed2004

Histology and ultrastructure of the gut epithelium of the neotenic cave salamander, Proteus anguinus (Amphibia, Caudata).

Histological, histochemical, and ultrastructural features of the gut of the European endemic cave salamander Proteus anguinus were studied. The gut is a relatively undifferentiated muscular tube lined with a simple columnar epithelium containing numerous goblet cells. The mucosa and underlying lamina propria/submucosa are elevated into a number of high longitudinal folds projecting into the lumen. The enterocytes are covered apically with uniform microvilli. Irregularity in the arrangement of microvilli was observed. Occasionally, irregular protrusions of the cytoplasm appear between groups of microvilli. Pinocytotic activity occurs at the bases of the intermicrovillous space. Mitochondria are numerous in the apical cytoplasm and basally beneath the nuclei. The supranuclear cytoplasm contains most of the cell organelles. The lateral plasma membranes of adjacent cells interdigitate and are joined by junctional complexes. The periodic acid-Schiff (PAS) reaction, indicating neutral mucosubstances, is positive only in the apical brush border of enterocytes and in goblet cells. The goblet cells also stained with Alcian blue (AB), at pH 2.5, thus revealing the presence of carboxylated glycosaminoglycans. Compact aggregations of AB- and PAS-negative cells are situated directly below the epithelium. Mitotic figures are present in individual clusters of cells. The fine structure of cells in these clusters indicated that these cells could be responsible for renewal of intestinal epithelium. Numerous endocrine-like cells could also be seen. The closely packed smooth muscle cells and amorphous extracellular material with collagen fibrils constitute a net-like structure under the basal lamina that is very closely associated with the epithelium. There are numerous acidophilic granular cells between epithelial cells, in the lamina propria/submucosa, and between cells aggregations. They seem to be associated with nematode infections and possibly constitute a humoral defense mechanism.

Animals↗
PubMed1981

The in-vitro interaction of eosinophils, neutrophils, macrophages and mast cells with nematode surfaces in the presence of complement or antibodies.

The adherence in vitro of leucocytes to the surface of various stages in the life cycle of T. spiralis and N. brasiliensis in the presence of serum was examined. Considerable differences were observed in the behaviour of mast cells, eosinophils, neutrophils and macrophages in this interaction. Mast cells adhered for a short time, did not flatten onto the surface and did not degranulate. Adherence ceased after 4-6 hr. Eosinophils adhered within minutes to the surface or worms, flattened and degranulated; only their cytoplasmic remnants could be seen on the worms' surface after 24 hr in culture. In contrast, only a small area of the cytoplasmic membrane of neutrophils flattened on the surface of the worms and adherence ceased after 2-24 hr. The NBT conversion reaction showed a positive deposit at the interface between neutrophils and parasites during neutrophil adherence. This deposit remained as "foot prints" on the surface of the nematodes following neutrophil detachment. This positive NBT reaction occurred only with neutrophils and not with eosinophils, mast cells or macrophages. Macrophages adhered permanently to the surface of these worms, they did not flatten and retained their integrity. Under the light microscope the cytoplasmic inclusions appeared to decrease in size during culture. Electron microscopy revealed the presence of fewer granules and an increased number of vacuoles in later cultures of macrophages. These findings are discussed in relationship to the immunopathology of nematode infection in vivo.

Animals↗
PubMed2006

The proteome of mouse mucosal mast cell homologues: the role of transforming growth factor beta1.

Mast cells migrate to the mucosal epithelium during intestinal nematode infections in mice, where they express abundant mucosal mast cell-specific proteases, mouse mast cell protease-1 and -2 (MCPT1 and MCPT2). Expression of these proteases is strictly controlled by transforming growth factor-beta1 (TGF-beta1) in the epithelium. In vitro homologues of mucosal mast cells are generated by culturing bone marrow-derived mast cells (BMMC) in the presence of TGF-beta1. We examined the proteome of BMMC cultured either in the presence of TGF-beta1 (n = 5) or of a neutralising anti-TGF-beta1 antibody (n = 5). Cell extracts were examined by 2-DE, and changes in expression levels of protein spots were determined by densitometry. Spots of interest were identified by tryptic peptide mapping. In addition to the up-regulation of MCPT1 and MCPT2, which accounted for approximately 40% of all soluble protein in the TGF-beta1 treated cells, MCPT7 was modestly up-regulated by TGF-beta1, and calnexin was up-regulated fivefold. A 7.6-fold down-regulation of galectin-1 was verified by Western blotting and FACS analysis. Galectin-1 is located on the cell surface where it mediates cellular adhesion to basement membranes. Regulation of its expression by TGF-beta1 may be of relevance to mast cell adhesion within the epithelium.

Animals↗
PubMed2005

Autoimmune ovarian disease in day 3-thymectomized mice: the neonatal time window, antigen specificity of disease suppression, and genetic control.

Discovery of the CD4+CD25+ T cells has stemmed from investigation of the AOD in the d3tx mice. Besides CD4+CD25+ T cell depletion, d3tx disease induction requires effector T cell activation prompted by lymphopenia. This is supported by other neonatal AOD models in which T cell-mediated injury has been found to be triggered by immune complex or Ag immunization. In addition, there is growing evidence that support a state of neonatal propensity to autoimmunity, which depends on concomitant endogenous antigenic stimulation, concomitant nematode infection, resistance to CD4+CD25+ T cell regulation, and participation of the neonatal innate system. The suppression of d3tx disease by polyclonal CD4+CD25+ T cells appears to be dependent on endogenous Ag and the persistence of regulatory T cells. Thus, suppression of AOD occurs in the ovarian LN, and AOD emerges upon ablation of the input regulatory T cells; and in AIP, the hormone-induced expression of prostate Ag in the CD4+CD25+ T cell donors rapidly enhances the capacity to suppress disease over Ag negative donors. Finally, genetic analysis of AOD and its component phenotypes has uncovered seven Aod loci. As the general themes that emerged, significant epistatic interactions among the loci play a role in controlling disease susceptibility, the majority of the Aod loci are linked to susceptibility loci of other autoimmune diseases, and the genetic intervals encompass candidate genes that are differentially expressed between CD4+CD25+ T cells and other T cells. The candidate genes include Pdcd1, TNFR superfamily genes, H2, Il2, Tgfb, Nalp5 or Mater, an oocyte autoAg that reacts with autoantibody in sera of d3tx mice.

Animals↗
PubMed1992

Adhesive knob formation by conidia of the nematophagous fungus Drechmeria coniospora.

We studied conidiogenesis and adhesive knob formation (maturation) by newly developed conidia of the nematophagous fungus Drechmeria coniospora. Upon conidiogenesis on infected nematodes or during saprophytic growth of the fungus in axenic cultures compact clusters of conidia developed. Less than 10% of such clustered conidia matured; mature conidia were invariably located on the periphery of the clusters. The kinetics and rate of maturation of conidia were studied in in vitro systems and in soil. In both cases adhesive knobs were formed; the rate at which knobs were formed appeared to be determined by the age of the conidia, the temperature and the soil moisture. In addition, knob formation was suppressed at increasing conidial densities. Under favorable conditions, however, over 90% of the conidia matured within a period of 3 days. The rate of knob formation was neither influenced by the presence of nematodes nor by that of exogenous nutrients, which suggests that maturation is an autonomous process. Electron-microscopical analysis indicated that budding of the conidia at the initial stage of maturation occurred simultaneously with the deposition of the sticky, adhesive layer around the wall of the developing knob. The ecological significance of the time- and spatially separated maturation of conidia after conidiogenesis is discussed with respect to survival of the conidia.

Adhesiveness↗
PubMed1979

A preliminary investigation into the control of trichostrongylosis in calves in Kenya.

A series of 3 grazing experiments was carried out to collect data relevant for designing techniques to prevent trichostrongylosis in dairy calves in Kenya. In the first experiment 1 week in/5 weeks out rotation was compared with set stocking. The results indicated that rotation is not an effective control measure. In the second experiment the effects of daily removal of faeces from the field were investigated. This practice also had a limited effect in controlling nematode infection in calves. The third experiment concentrated on the influence of nutrition level. It was shown that feeding level does affect the growth rate but its effect on the course of the egg output was not clear-cut. The results also indicated that the dry season greatly reduces herbage infestation.

Animal Feed↗
PubMed2004

The influence of parasitism on the pharmacokinetics of moxidectin in lambs.

Most pharmacokinetic studies on anthelmintic drugs have been performed on non-parasitized animals. However, it seems likely that the parasite burden could influence the deposition of such drugs. The pharmacokinetics of moxidectin administered orally and by subcutaneous injection was compared in lambs exposed to nematode infection and in parasite naive lambs. Plasma samples were analyzed for moxidectin over 40 days post-treatment. The main pharmacokinetic parameters calculated demonstrated a significant change in drug deposition in infected lambs when compared to controls. The area under the plasma concentration-time curve was decreased 54% and 46% by infection in the subcutaneous and oral groups, respectively. There was also a major decrease in the mean residence time in parasitized lambs. In parallel, the clearance of the drug was increased by infection. Thus, parasite infection dramatically influences the disposition of moxidectin in lambs. These results may contribute to determining a therapeutic strategy adapted to heavily infested animals.

Animals↗
PubMed2005

Imidacloprid plus moxidectin topical solution for the prevention of heartworm disease (Dirofiloria immitis) in dogs.

A topically applied formulation containing 10% imidacloprid+2.5% moxidectin (Advocate/Advantage multi) has been developed for monthly application to dogs for the prevention of canine heartworm (HW) disease caused by Dirofilaria immitis; and for the treatment and control of flea infestations, mite infestations, and intestinal nematode infections. The efficacy of this formulation to prevent canine HW disease was confirmed at three study locations which included the use of 88 purpose-bred beagles 6-8 months of age. Two of these studies also evaluated the effects of post-treatment water exposure or shampooing on product performance. Each dog was infected with 50 third-stage D. immitis larvae on test days -30 to -45. Dogs were blocked according to gender and body weight on test day -1. Topically applied test articles were administered once on test day 0 as follows: 10% imidacloprid+2.5% moxidectin (52 dogs); 2.5% moxidectin mono solution (eight dogs); 10% imidacloprid mono solution (16 dogs); and placebo solution (12 dogs). Treatment dosages were applied to provide a minimum of 10 mg/kg imidacloprid and/or 2.5 mg/kg moxidectin. Subgroups of dogs were exposed to water to simulate swimming/rain exposure at designated post-treatment intervals. Additional dogs were shampooed at 90 min, 4 h, or 24 h post-treatment. All dogs were necropsied 110-119 days post-treatment for recovery of adult D. immitis. No adult D. immitis were recovered at necropsy from any of the dogs receiving 10% imidacloprid+2.5% moxidectin or 2.5% moxidectin mono solution, demonstrating 100% efficacy for prevention of D. immitis infection. A total of 701 adult D. immitis were recovered at necropsy from dogs receiving 10% imidacloprid mono solution or placebo (range of 11-40 D. immitis/dog). The efficacy of 10% imidacloprid+2.5% moxidectin treatment for the prevention of HW disease was not decreased when dogs were shampooed as early as 90 min post-treatment, or when dogs immersed in water 5 times post-treatment at weekly intervals.

Administration, Topical↗
PubMed1996

Inhibition of glutathione synthesis of Ascaris suum by buthionine sulfoximine.

We investigated the effect of DL-buthionine-S,R-sulfoximine (BSO), a selective glutathione (GSH)-depleting agent, on the GSH synthesis of Ascaris suum. The GSH concentrations of the reproductive and muscle tissues of A. suum were determined to be 8.5 +/- 0.3 and 14.3 +/- 1.3 (n = 3) nmol/mg protein, respectively. After treatment of the parasites with 10 microM BSO for 24 h, the GSH content of the reproductive tissue of A. suum was totally depleted as compared with that of untreated controls. However, the GSH levels of the muscle tissue were reduced to only 50% after treatment of the worms for 24 h with 10 microM BSO. Exogenous GSH had no significant effect on the GSH level of the parasites when the worms were incubated for 4 h in RPMI 1640 medium supplemented with 1 mM GSH. In the presence of exogenous GSH, BSO was less effective in depleting the GSH levels of the parasites, which may indicate that the parasites can replenish their GSH levels. GSH depletion, which has been discussed as being therapeutically effective when normal and tumor cells or parasites have markedly different requirements for GSH, may have applications in the development of drugs against nematode infections.

Animals↗
PubMed1996

Effect of haloallylamines on polyamine oxidase activity and spermine levels in Ascaris suum.

In parasitic nematodes the rate-limiting step in the polyamine interconversion pathway is catalysed by polyamine oxidase. MDL 72527, the specific inhibitor of mammalian polyamine oxidase, had no effect on the Ascaris suum enzyme, whereas its activity was inhibited in a time-dependent manner by the haloallylamine MDL 72145, originally designed as a specific inhibitor of monoamine oxidase A and B. The dissociation constant (Ki) was found to be 0.9 microM and the enzyme half-life under saturation conditions (t50) was determined to be 0.8 min. Incubation of A. suum in vitro in the presence of 50 microM MDL 72145 for 6 h resulted in a decrease in polyamine oxidase activity to about 20% of the control value, and spermine concentrations simultaneously increased about 200%. Both results suggest that MDL 72145 might be a chemical lead compound for the design of new chemotherapeutic agents against nematode infections.

Allylamine↗
PubMed2005

Isolation and characterization of a serine protease from the nematophagous fungus, Lecanicillium psalliotae, displaying nematicidal activity.

Lecanicillium psalliotae produced an extracellular protease (Ver112) which was purified to apparent homogeneity giving a single band on SDS-PAGE with a molecular mass of 32 kDa. The optimum activity of Ver112 was at pH 10 and 70 degrees C (over 5 min). The purified protease degraded a broad range of substrates including casein, gelatin, and nematode cuticle with 81% of a nematode (Panagrellus redivivus) being degraded after treating with Ver112 for 12 h. The protease was highly sensitive to PMSF (1 mM) indicating it to be a serine protease. The N-terminal amino acid residues of Ver112 shared a high degree of similarity with other cuticle-degrading proteases from nematophagous fungi which suggests a role in nematode infection.

Amino Acid Sequence↗