Isolation and partial structural characterization of new Kunitz-type trypsin inhibitors from the pike cestode Triaenophorus nodulosus.

The inhibitors produced by the parasitic worms successfully protect them from the host's proteases and are supposed to underlie the host-parasite specificity. Our previous study has shown that the extracts from the pike tapeworm Triaenophorus nodulosus inhibit host proteinases and commercial trypsin. We aimed to isolate and identify the components responsible for trypsin inactivation. After a two-step separation the molecular masses were measured by SE-HPLC. The sample proved to contain four fractions represented by polypeptides (1-45 kDa) and low-molecular hydrophobic compounds. According to SDS-PAGE analysis, the major polypeptides in the fractions displaying the highest inhibition had masses of 14.4 kDa. The study culminated in partial N-terminal amino acid sequence analysis with a further search for homology. The research revealed two novel Kunitz-type proteins potentially responsible for the inhibitory capacity of the tapeworms against trypsin. Our findings extend the list of cestodes relying on Kunitz-type proteins in the host-parasite molecular cross-talk.

Characterization of Tapeworm Metabolites and Their Reported Biological Activities.

Parasitic helminths infect billions of people, livestock, and companion animals worldwide. Recently, they have been explored as a novel therapeutic modality to treat autoimmune diseases due to their potent immunoregulatory properties. While feeding in the gut/organs/tissues, the parasitic helminths actively release excretory-secretory products (ESP) to modify their environment and promote their survival. The ESP proteins of helminths have been widely studied. However, there are only limited studies characterizing the non-protein small molecule (SM) components of helminth ESP. In this study, using GC-MS and LC-MS, we have investigated the SM ESP of tapeworm Dipylidium caninum (isolated from dogs) which accidentally infects humans via ingestion of infected cat and dog fleas that harbor the larval stage of the parasite. From this D. caninum ESP, we have identified a total of 49 SM (35 polar metabolites and 14 fatty acids) belonging to 12 different chemotaxonomic groups including amino acids, amino sugars, amino acid lactams, organic acids, sugars, sugar alcohols, sugar phosphates, glycerophosphates, phosphate esters, disaccharides, fatty acids, and fatty acid derivatives. Succinic acid was the major small molecule present in the D. caninum ESP. Based on the literature and databases searches, we found that of 49 metabolites identified, only 12 possessed known bioactivities.

Effects of tapeworm infection on absorption and excretion of zinc and cadmium by experimental rats.

The main objective of this study was to determine how rat tapeworms affect the excretion of zinc and cadmium through rat feces. Male rats (Rattus norvegicus var. alba) were divided into four groups, and the experiment was conducted over a 6-week period. The control groups (00; 0T) were provided with a standard ST-1 rodent mixture and received 10.5 mg of Zn/week. Groups P0 and PT were fed a mixture supplemented with the hyperaccumulating plant Arabidopsis halleri at a dosage of 123 mg Zn/week and 2.46 mg Cd/week. Groups 0T and PT were infected with the rat tapeworm (Hymenolepis diminuta). Fecal samples were collected 24 h post exposure. Zinc and cadmium concentrations in rat feces were analyzed using inductively coupled plasma optical emission spectrometry. Tapeworm presence decreased the amount of metals excreted through the feces of the host throughout the entire experiment, with the exception of 1 week (control group). No statistically significant differences between zinc excretion rates in the control groups (00 and 0T) were detected at any time throughout the experiment. A statistically significant difference between zinc excretion rates (p < 0.05) in the exposed groups (P0 and PT) was detected in 2 of the 6 monitored weeks. Group PT excreted significantly less cadmium (p < 0.01) than group P0 did in three of the 6 weeks. Overall, our results indicate that tapeworms are able to influence the excretion of metals by their host. Tapeworms accumulate metals from intestinal contents. It is not clear whether tapeworms carry out this process before the host tissues absorb the metals from the intestines or the tapeworms accumulate metals excreted from the body of the host back to the intestines. Most likely, it is a combination of both phenomena.

The Effect of Parasite Infection on Stable Isotope Turnover Rates of δ15N, δ13C and δ34S in Multiple Tissues of Eurasian Perch Perca fluviatilis.

Stable isotope analysis of commercially and ecologically important fish can improve understanding of life-history and trophic ecology. However, accurate interpretation of stable isotope values requires knowledge of tissue-specific isotopic turnover that will help to describe differences in the isotopic composition of tissues and diet. We performed a diet-switch experiment using captive-reared parasite-free Eurasian perch (Perca fluviatilis) and wild caught specimens of the same species, infected with the pike tapeworm Triaenophorus nodulosus living in host liver tissue. We hypothesize that metabolic processes related to infection status play a major role in isotopic turnover and examined the influence of parasite infection on isotopic turn-over rate of carbon (δ13C), nitrogen (δ15N) and sulphur (δ34S) in liver, blood and muscle. The δ15N and δ13C turnovers were fastest in liver tissues, followed by blood and muscle. In infected fish, liver and blood δ15N and δ13C turnover rates were similar. However, in infected fish, liver and blood δ13C turnover was faster than that of δ15N. Moreover, in infected subjects, liver δ15N and δ13C turnover rates were three to five times faster than in livers of uninfected subjects (isotopic half-life of ca.3-4 days compared to 16 and 10 days, respectively). Blood δ34S turnover rate were about twice faster in non-infected individuals implying that parasite infection could retard the turnover rate of δ34S and sulphur containing amino acids. Slower turnover rate of essential amino acid could probably decrease individual immune function. These indicate potential hidden costs of chronic and persistent infections that may have accumulated adverse effects and might eventually impair life-history fitness. For the first time, we were able to shift the isotope values of parasites encapsulated in the liver by changing the dietary source of the host. We also report variability in isotopic turnover rates between tissues, elements and between infected and parasite-free individuals. These results contribute to our understanding of data obtained from field and commercial hatcheries; and strongly improve the applicability of the stable isotope method in understanding life-history and trophic ecology of fish populations.

Comparative transcriptomics of stickleback immune gene responses upon infection by two helminth parasites, Diplostomum pseudospathaceum and Schistocephalus solidus.

Immune systems of vertebrates are much more diverse than previously thought, in particular at the base of the vertebrate clade. RNA-seq was used to describe in detail the transcriptomic response of stickleback hosts to infection by two helminth parasites, the trematode Diplostomum pseudospathaceum (2 genotypes plus a genotype mix) and the cestode Schistocephalus solidus. Based on a global transcription profiling, we present immune genes that are active during chronic or multiple repeated infection. We found that the transcription profiles of D. pseudospathaceum genotypes were as divergent as those of the two parasite species. When comparing the host immune response, only 5 immune genes were consistently upregulated upon infection by both species. These genes indicated a role for enhanced toll like receptor (TLR) activity (CTSK, CYP27B1) and an associated positive regulation of macrophages (CYP27B1, THBS1) for general helminth defense. We interpret the largely differentiated gene expression response among parasite species as general redundancy of the vertebrate immune system, which was also visible in genotype-specific responses among the different D. pseudospathaceum infections. The present study provides the first evidence that IL4-mediated activation of T-helper lymphocyte cells is also important in anti-helminthic immune responses of teleost fish.

Effect of Intestinal Tapeworm Clestobothrium crassiceps on Concentrations of Toxic Elements and Selenium in European Hake Merluccius merluccius from the Gulf of Lion (Northwestern Mediterranean Sea).

The capacity for heavy metal bioaccumulation by some fish parasites has been demonstrated, and their contribution to decreasing metal concentrations in tissues of parasitized fish has been hypothesized. The present study evaluated the effect of the cestode Clestobothrium crassiceps on the accumulation of trace elements in 30 European hake, Merluccius merluccius, in Spain (half of them infested by C. crassiceps). Tissue samples from all M. merluccius and specimens of C. crassiceps from the infected hakes were collected and stored until element analysis by inductively coupled plasma mass spectrometry (ICP-MS). Arsenic, mercury, and selenium were generally present in lower levels in the cestode than in all hake tissues. The mean value of the muscular Se:Hg molar ratio in the infested subsample was higher than that in hakes without cestodes. Values indicate that the edible part of infested hakes presents a lower amount of Cd and Pb in relation to noninfested hakes.

Consistent isotopic differences between Schistocephalus spp. parasites and their stickleback hosts.

Parasite-host systems show markedly variable patterns in isotopic fractionation: parasites can be either depleted or enriched in ¹5N and ¹³C as compared to their hosts. However, it remains unknown whether isotopic fractionation patterns are similar in comparable parasite-host systems from markedly different ecosystems. Results of this study show that large-sized Schistocephalus spp. endoparasites are consistently depleted in ¹5N (by on average -2.13 to -2.20 ‰) as compared to their nine-spined stickleback Pungitius pungitius and three-spined stickleback Gasterosteus aculeatus hosts. The differences between parasites and host for both δ¹5N and δ¹³C were consistent in both study systems despite marked biogeographical differences between the study localities. Although the stable isotope values in general were strongly correlated between the hosts and their parasites, Schistocephalus specimens occupying the same nine-spined stickleback host showed sometimes substantial individual variation in δ¹³C. This might be due to selective use of different carbon sources, or different metabolic or feeding rates. Further studies on selective feeding, physiology and metabolism of parasites are needed to better understand the role of parasites in the structure and functioning of aquatic food webs.

In vitro ovicidal and cestocidal effects of toxins from Bacillus thuringiensis on the canine and human parasite Dipylidium caninum.

Bacillus thuringiensis is a gram-positive soil-dwelling bacterium that is commonly used as a biological pesticide. This bacterium may also be used for biological control of helminth parasites in domestic animals. In this study, we evaluated the possible ovicidal and cestocidal effects of a total protein extract of B. thuringiensis native strains on the zoonotic cestode parasite of dogs, Dipylidium caninum (D. caninum). Dose and time response curves were determined by coincubating B. thuringiensis proteins at concentration ranging from 100 to 1000 µ g/mL along with 4000 egg capsules of D. caninum. Egg viability was evaluated using the trypan blue exclusion test. The lethal concentration of toxins on eggs was 600 µ g/ml, and the best incubation time to produce this effect was 3 h. In the adult stage, the motility and the thickness of the tegument were used as indicators of damage. The motility was inhibited by 100% after 8 hours of culture compared to the control group, while the thickness of the cestode was reduced by 34%. Conclusively, proteins of the strain GP526 of B. thuringiensis directly act upon D. caninum showing ovicidal and cestocidal effects. Thus, B. thuringiensis is proposed as a potential biological control agent against this zoonosis.

The genomes of four tapeworm species reveal adaptations to parasitism.

Tapeworms (Cestoda) cause neglected diseases that can be fatal and are difficult to treat, owing to inefficient drugs. Here we present an analysis of tapeworm genome sequences using the human-infective species Echinococcus multilocularis, E. granulosus, Taenia solium and the laboratory model Hymenolepis microstoma as examples. The 115- to 141-megabase genomes offer insights into the evolution of parasitism. Synteny is maintained with distantly related blood flukes but we find extreme losses of genes and pathways that are ubiquitous in other animals, including 34 homeobox families and several determinants of stem cell fate. Tapeworms have specialized detoxification pathways, metabolism that is finely tuned to rely on nutrients scavenged from their hosts, and species-specific expansions of non-canonical heat shock proteins and families of known antigens. We identify new potential drug targets, including some on which existing pharmaceuticals may act. The genomes provide a rich resource to underpin the development of urgently needed treatments and control.

Studies on some metacestodes immunohistochemical response in mice as a model for human cysticercosis: I. Role of Th1 and Th2 cytokines in experimental liver granuloma of Mesocestoides corti infected mice.

Intraperitoneal infection of female BALB/C mice with the Mesocestoides corti larvae leading to an intense inflammatory response associated with symptoms started to appear between 4-5 weeks post-infection. The hepatic changes in the process of granuloma formation after intraperitoneal infection with the tetrathiredia of M. corti were analyzed. Histopathological changes were observed after five days of infection. As a result of this parasitic infection, an extensive inflammatory response took place with infiltrating cells first tracking the migratory pathway surrounding the parasites. The pathology associated with these processes was very destructive for the liver parenchyma. As the infection progressed, neutrophils, macrophages, fibroblasts, mast cells and lymphocytes were recruited in the tissue. These immune cells started to surround the parasites, leading to the formation of granuloma around them. Both Th1 and Th2 cytokines interact with each other to regulate and modulate the hepatic granuloma formation in infected mice.

Nutritional status and gene expression along the somatotropic axis in roach (Rutilus rutilus) infected with the tapeworm Ligula intestinalis.

The tapeworm Ligula intestinalis inhibits gametogenesis of its fish host, the roach (Rutilus rutilus). We investigated whether L. intestinalis infection makes significant demands on nutritional resources and consequently manipulates the endocrine somatotropic axis of roach. Two groups of naturally infected and uninfected roach were studied: a field group (natural feeding) and a laboratory group (ad libitum food supply). In females, no significant impact of parasitization on storage substrates (glycogen, lipids, and protein) was detected, whereas in males, either lipid content of the liver (field group) or lipid of the muscle and glycogen of the liver (laboratory group) were slightly decreased. Except for the females of the field group, higher mRNA expression of growth hormone (gh) in the pituitary of infected fish was observed. Furthermore, the expression of hypophyseal somatolactin α and ß (slα, slß) was up-regulated in infected females of the field and laboratory group, respectively. In liver and muscle, mRNA expression of insulin-like growth factors (igf1, igf2) and igf receptor (igfr) remained either unchanged or were up-regulated with infection. Parasitization showed inconsistent effects on gh receptor 1 (ghr1) expression in liver and muscle, whereas ghr2 mRNA was mostly not influenced by infection. In general, the expression profile of genes involved in the somatotropic axis as well as the content of storage substances in infected roach did not resemble that of food-deprived fish either under natural or ad libitum feeding. In conclusion, the present study does not indicate starvation of L. intestinalis infected roach, and it is suggested that the inhibition of reproduction attenuated the nutritional demand of parasitization.

Schistocephalus solidus infections increase gonadotropins and gonadotropin releasing hormone (GnRH3) mRNA levels in the three-spined stickleback, Gasterosteus aculeatus.

Parasites often impair the reproduction of their hosts, one well known case being the cestode Schistocephalus solidus which is a common parasite in three-spined sticklebacks, Gasterosteus aculeatus. One of the possible ways that this could be exerted is by suppression on the brain-pituitary-gonadal (BPG) axis. In this study, mRNA levels of FSH-ß and LH-ß and of GnRH2 (cGnRH II) and GnRH3 (sGnRH) were measured via Q-PCR in infected and uninfected fish sampled from the field a few weeks before the onset of breeding. The pituitary mRNA levels of both FSH-ß and LH-ß were higher in infected males than in uninfected males. Also in females, FSH-ß mRNA levels were higher in infected individuals than in others, whereas there was no significant difference found in LH-ß expression. Brain mRNA levels of GnRH3 were higher in infected fish than in uninfected fish in both sexes, but no difference was found in GnRH2 mRNA levels. Thus, infection by S. solidus was able to alter the expressions not only of gonadotropins (GtHs), but also of GnRH which has not been observed previously. However, the effects are opposite to what should be expected if the parasite suppressed reproduction via actions on the brain-pituitary level. The gonads are perhaps more likely to be impaired by the parasites in other ways, and changed feedbacks on the BPG axis could then lead to the increases in GtHs and GnRH.

Dynamics of hepatic stellate cells, collagen types I and III synthesis and gene expression of selected cytokines during hepatic fibrogenesis following Mesocestoides vogae (Cestoda) infection in mice.

In the present study, the relationship between progression of Mesocestoides vogae infection in the liver of mice, the accumulation rate of collagen types I and III, gene expression of fibrogenic factors and cytokines was examined within 6weeks p.i. Due to asexual multiplication, the total number of larvae in the liver increased considerably and 63.4% were found in collagen capsules on day 42 p.i. Intense staining for both collagens was recorded in the activated hepatic stellate cells (HSCs) throughout the period of this study in the inflammatory lesions. With progressing infection, cellular expression of both collagens was confined to the flat cells, myofibroblasts, which were scattered among collagen fibres in parenchymal lesions and capsules. Collagen-positive areas mirrored immunostaining of alpha-smooth muscle actin (alpha-SMA) in HSCs and myofibroblasts. Gene expression of both collagens increased rapidly within 14days p.i. and their expression pattern resembled that for pro-fibrotic cytokine transforming growth factor (TGF)-beta1 and alpha-SMA protein. IL-10 cytokine expression was up-regulated following day 14 p.i. and that of IL-13 was up-regulated early p.i., then transcription elevated gradually mirroring the activity of other pro-fibrotic markers. In contrast, transcription activity of TNF-alpha and IFN-gamma was elevated shortly after infection, followed by the partial down-regulation of gene expression, indicating the lack of larval killing, enhanced granulomatous inflammation and the perpetuation of hepatic fibrosis. Histomorphometric analysis of the parenchymal fibrous lesions, surface areas of larvae surrounded with the inflammatory infiltrates and surface areas of developing or mature larva-containing granulomas, correlated with the proportion of free and encapsulated larvae, immunostaining and gene expression patterns of collagens and pro-fibrotic markers. At a later stage of infection (day 28 p.i. onwards) collagen I-positive areas occupied a greater surface area and formed mature larval capsules and scars in the liver. In contrast, collagen III was less abundant and was localised mainly in the fibrous lesions in damaged parenchyma, suggesting their specific up-regulation as the part of host-protecting and tissue-healing responses.

Influence of parasitism on trace element contents in tissues of red fox (Vulpes vulpes) and its parasites Mesocestoides spp. (Cestoda) and Toxascaris leonina (Nematoda).

Bioaccumulation of cadmium, chromium, copper, manganese, nickel, lead, and zinc in 56 foxes (Vulpes vulpes) and their parasites Mesocestoides spp. (Cestoda) and Toxascaris leonina (Nematoda) was studied. The levels of heavy metals were determined in the livers and kidneys of the animals depending on parasitism in the following ranges: Pb, 0.029-3.556; Cd, 0.055-9.967; Cr, 0.001-0.304; Cu, 4.15-41.15; Mn, 1.81-19.94; Ni: 0.037-0.831; Zn, 52.0-212.9 microg/g dry weight (dw). Cd in parasites (0.038-3.678 microg/g dw) were comparable with those in the livers of the host and lower than in the kidneys (0.095-6.032 microg/g dw). Contents of Pb, Cr, Cu, Mn, Ni, and Zn in cestodes were predominantly higher than those in the kidney and liver of the host. Median lead levels in Mesocestoides spp. (45.6 microg/g dw) were 52-fold higher than in the kidney and liver of the red fox (Vulpes vulpes) infected by both parasites and median Pb values in T. leonina (8.98 microg/g dw) were 8-fold higher than in the tissues of the parasitized red fox. Bioaccumulation factors of copper, zinc, nickel, and manganese are lower than those of lead and mostly range from 1.9 to 24 for Mesocestoides spp. and from 1.5 to 6 for nematode T. leonina depending on the tissue of host and element. A significant decrease in the content of Pb was found in the kidney of animals infected by T. leonina (0.260 microg/g dw) as well as those infected by Mesocestoides spp. (0.457 microg/g dw) in comparison with the lead content (0.878 microg/g dw) in the kidneys of the nonparasitized red fox. Regardless of a bioaccumulation of copper and manganese in the parasites, a significant increase of the concentrations of Mn and Cu was observed in the host's livers infected predominantly by Mesocestoides spp.

IL-4(-/-) mice with lethal Mesocestoides corti infections--reduced Th2 cytokines and alternatively activated macrophages.

Protection against Mesocestoides corti, a cestode that invades vital organs, is dependent on the production of IL-4, as IL-4(-/-) mice were found to have higher parasite burdens when compared with wild-type mice. The goal of this study was to investigate the role of IL-4 in immunity to M. corti, focusing on the immunological profile and on potential mediators of pathology. IL-4(-/-) mice infected with M. corti showed 100% mortality by 32 days, whereas wild-type mice survived for approximately 1 year. Parasite burdens were significantly increased in the liver, peritoneal, and thoracic cavities of IL-4(-/-) mice, associated with impaired recruitment of inflammatory cells and a reduction in monocytes and macrophages. IL-5 production by splenocytes and expression in liver tissue was decreased in infected IL-4(-/-) mice compared with wild-type mice. In contrast, IL-4(-/-) mice produced increased amounts of IFNgamma and TNFalpha. Alternatively activated macrophages were a major feature of liver granulomas in wild-type mice evidenced by Arginase I expression, while livers from infected IL-4(-/-) mice showed impaired alternative macrophage activation without increased classical macrophage activation. Thus, lethality during M. corti infection of IL-4(-/-) mice is associated with decreased Th2 cytokines, increased Th1 cytokines and impairment of alternatively activated macrophages.

Influence of parasitism on the use of small terrestrial rodents in environmental pollution monitoring.

Bioaccumulation of cadmium, chromium, copper, manganese, nickel, lead and zinc in small terrestrial rodents - voles and their cestode parasite Paranoplocephala dentata was studied. Contents of Pb, Mn, Ni and Zn in the parasite were found to be higher than in the kidney and liver of the parasitized animals. Lead level in the cestode was 37 fold higher than in the liver of the infected rodents. Bioaccumulation factors of zinc, nickel and manganese in the cestode are mostly in the range from 2 to 4.5. Considering the different contents of manganese and zinc in livers of non-parasitized and parasitized rodents, kidney tissue was found to be more reliable than liver as an indicator of environmental pollution by manganese and zinc; the kidneys of parasitized animals showed no significant change in the concentrations of those elements that are accumulated in the cestode.

Expression of gonadotropin subunits in roach (Rutilus rutilus, Cyprinidae) infected with plerocercoids of the tapeworm Ligula intestinalis (Cestoda).

Plerocercoids of the tapeworm Ligula intestinalis (Cestoda: Bothriocephalidea) have been reported to inhibit gametogenesis of their intermediate fish hosts. However, mechanistic studies are rare and the proximate cues leading to impaired reproduction still remain unknown. In the present study we investigated the effects of infection by L. intestinalis on reproductive parameters of roach (Rutilus rutilus, Cyprinidae), a common fish host of this parasite. Field studies on roach demonstrated that in both genders infection prevented gonad development. As revealed by quantitative PCR, infection was accompanied by essentially lower pituitary expression of follicle-stimulating hormone beta-subunit (FSHbeta) and luteinizing hormone beta-subunit (LHbeta) mRNA compared with uninfected roach, providing clear evidence for gonadotropin-insufficiency as the cause of arrested gametogenesis. Under controlled laboratory conditions infected roach showed lower mRNA levels of FSHbeta but not of LHbeta, despite histology revealing similar gonad stages as in uninfected conspecifics. These findings indicate the involvement of FSH rather than LH in mediating effects of infection early during gonad development in roach. Moreover, the impact of L. intestinalis on reproductive parameters of roach appeared to be independent of the parasite burden. Together, these data provide valuable information on the role of FSH and LH as mediators of parasite-induced sterilization in a vertebrate and implicate the selective inhibition of host reproduction by L. intestinalis as a natural source of endocrine disruption in fish.

[Dynamics of physiological parameters in the nestling of black-backed gull Larus marinus experimentally infested by the cestode Microsomacanthus ductilus (Cestoda: Hymenolepididae)].

The effect of the invasion with the cestode Microsomacanthus ductilus on physiological and biochemical processes in black-backed gull Larus marinus was examined. Experimental invasion of the gull nestling by the cestodes has been performed. Dynamics of the protein, lipid, and carbohydrate metabolism in the time history of the invasion was observed, in comparison with noninfested nestling. Increasing of the content of alpha-globulins and decreasing of the content of protein and albumin in the blood plasma of experimentally infested birds were registered to 4th day after invasion. To 7th day after invasion the level of general lipids and phospholipids decreases, while the content of gamma-globulins and modified form of albumin increases. To 10th day after invasion symptoms of intoxication were observed, but some parameters proved to be reverted to normal condition. So, it can be assumed, that the most intensive reorganization of the metabolism in infested birds takes place in the period between 4th and 7th days after infestation. Possible causes of the observed phenomena are discussed.

Suppressive activity of epinastine hydrochloride on eosinophil activation in vitro.

The influence of a histamine H1 receptor antagonist, epinastine hydrochloride (EP), on eosinophil functions was examined in vitro and in vivo. The first set of experiments was undertaken to examine whether EP could suppress eosinophilia and IgE hyperproduction induced by Mesocestoides cortii infection in BALB/c mice. The number of peripheral blood eosinophils and levels of IgE were examined 21 days after infection. Oral administration of EP at a daily dose of 0.3 mg/kg, which is the recommended human therapeutic dose, for 21 days was not able to suppress either peripheral blood eosinophilia or IgE hyperproduction, which was observed in mice infected with M. cortii. The second part of the experiment was designed to examine the influence of EP on eosinophil activation induced by stem cell factor (SCF) stimulation in vitro. Eosinophils were obtained from M. cortii-infected mice and stimulated with SCF in the presence of different concentrations of EP for 24 h. The addition of EP into cell cultures suppressed eosinophil activation induced by SCF stimulation as assessed by measuring the contents of acronym for Regulated upon Activation, Normal T cell Expressed and presumably Secreted (RANTES), macrophage inflammatory protein-1beta (MIP-1beta) and leukotriene C4 (LTC4) levels in culture supernatants. The minimum concentration of EP which caused significant suppression of factor productions was 25 ng/ml, which is similar to the concentration in plasma after oral administration of the therapeutic dose in humans. These results may suggest that EP exerts inhibitory effects on eosinophil activation and results in favorable modification of the clinical status of allergic patients.

Heavy metal accumulation in small terrestrial rodents infected by cestodes or nematodes.

The aim of the present study was to assess whether there is a difference in accumulation of heavy metal ions (Cd, Cr, Cu, Mn, Ni, Pb and Zn) in hosts (small mammals) infected by cestode parasites when compared to those without cestode infection. The abundance of gastrointestinal parasites and bioaccumulation of heavy metals in host livers and kidneys were measured. Contents of heavy metals in hosts were determined by ICP OES method. The hosts with cestode infection (Paranoplocephala sp.) had lower contents of heavy metals in their livers and kidneys compared to hosts with nematode infection (Mastophorus muris). The content of Pb, Cd, Cr, Cu and Ni was higher in kidneys than in livers, in both (cestode and nematode infected) rodents while the content of Mn was higher in livers. Content of Zn was similar. The content of heavy metals in host was decreasing with the increasing abundance of cestodes (Paranoplocephalo sp.). Species-response models to particular heavy metals are presented.