Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Echinococcus multilocularis”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 253 records · Page 14Linked to original sources
PubMed2004

Long-term in vitro cultivation of Echinococcus multilocularis metacestodes under axenic conditions.

We report here on the development of an in vitro system for the long-term cultivation of Echinococcus multilocularis larvae under axenic conditions. In the absence of feeder cells from the host, long-term survival of the parasite depended strictly on low oxygen conditions and the presence of reducing agents in the medium. Host serum supported survival of the parasite but the growth of metacestode vesicles and differentiation towards the protoscolex stage only occurred in the presence of culture medium that was preconditioned by hepatoma cells or several other immortal cell lines. On the basis of this in vitro system, future analyses on the identification of host-derived growth factors for E. multilocularis will be greatly facilitated.

Animals↗
PubMed1989

Echinococcus multilocularis: inhibition of murine neutrophil and macrophage chemotaxis.

Resident peritoneal neutrophils and macrophages from mice infected with 50 +/- 5 cysts of Echinococcus multilocularis were collected at 2, 4, 6, 8, 10, and 16 weeks postinfection. Their ability to respond and migrate to purified parasite larval antigens or endotoxin-activated mouse serum (EAMS) in comparison to normal peritoneal cells from uninfected mice was tested in vitro using Boyden chambers. Early in the infection, both cell types responded to the specific and nonspecific chemoattractants as the control group. However, at 8 and 10 weeks postinfection, the neutrophils and macrophages lost their response to parasite antigens but retained their ability to migrate to EAMS. Toward the 12th and 16th week postinfection, both cell types lost their ability to migrate to the specific as well as the nonspecific factors. The data presented suggest that the cellular mechanisms of recognition and chemotaxis in mice infected with alveolar hydatid cysts are impaired.

Animals↗
PubMed1990

Chemotherapy of experimental Echinococcus multilocularis in jirds.

A total of 50 jirds (Meriones unguiculatus) were infected by intraperitoneal implantation of 0.20 g metacestode tissue of Echinococcus multilocularis. The feed of 4 groups of 10 animals each was treated for 35 days with 500 ppm albendazole, flubendazole, mebendazole or praziquantel; 1 group of 10 jirds served as unmedicated controls. At autopsy 2 weeks after the end of medication, the transplants had increased in size and weight, reaching a total weight of 78.11 g in the control group, 21.60 g in the albendazole-treated group, 3.63 g in the flubendazole-treated group, 7.00 g in the mebendazole-treated group and 68.91 g in the praziquantel-treated group. The percentage in reduction of parasitic tissue weight as compared with control values was 72%, 95%, 91% and 12%, respectively. The calculated daily drug intake was approximately 48 mg/kg body weight. Drug-related side effects were not observed.

Albendazole↗
PubMed1980

[Experimental Echinococcus multilocularis infections of the maternal mouse and their significance for the offspring].

Experimental infection of mother mice by intraperitoneal injection of Echinococcus multilocularis cyst material does not result in the transfer of protective immunity to the offspring. In the contrary, if infected via the same route, filial mice show a lower antibody titer, when examined 36, 78 and 120 days p.i. and a higher worm burden (average: 1455 mg) in comparison with control mice born of non-infected mothers (average parasite weight: 844 mg). The question is discussed, whether these observations are due to the suppressive action of transferred antibodies or whether the offspring become immunologically tolerant by the transfer of parasite antigen.

Age Factors↗
PubMed1996

Molecular cloning, expression and characterization of a recombinant glutathione S-transferase from Echinococcus multilocularis.

We report the identification and characterization of the first cestode glutathione S-transferase (GST) cDNA sequence. A fragment of an Echinococcus multilocularis glutathione S-transferase cDNA was isolated by the polymerase chain reaction. Subsequently, a Lambda zap cDNA library prepared from mRNA from protoscolices of E. multilocularis was screened with this PCR fragment. A complete cDNA clone was isolated and the nucleotide sequence determined. Analysis of the E. multilocularis GST-deduced amino acid sequence indicates that it is clearly related to the mammalian mu-class GSTs. The E. multilocularis GST cDNA was expressed in Escherichia coli, using a protocol designed to produce the native enzyme rather than a fusion protein. The 25.5-kDa enzyme subunit was purified to homogeneity using glutathione-sepharose chromatography. Gel filtration demonstrated that this GST is enzymatically active as a homodimer. The recombinant enzyme had conjugating activity with organic hydroperoxides and with members of the trans,trans-2,4 alkadienal and trans-2-alkenal series, which are secondary products of lipid peroxidation.

Amino Acid Sequence↗
PubMed1992

Comparison of Montana and Alaska isolates of Echinococcus multilocularis in gerbils with observations on the cyst growth, hook characteristics, and host response.

To assess its biological distinctness, an isolate of Echinococcus multilocularis from Montana was compared with an isolate from Alaska in gerbils (Meriones unguiculatus) by means of intraperitoneal inoculations with protoscoleces. The cysts formed by the Montana isolate were entire, hyaline, and translucent, whereas those produced by the Alaska isolate were granular, yellowish, and opaque. Vesicles of the Montana isolate were larger, produced protoscoleces more slowly but in greater numbers, and required a longer period to develop surfacial germ cell protrusions, which were of smaller size. Also delayed was invasion of the laminate layer by granulocytes and macrophages, and a longer time was required for the appearance of pulmonary metastases. The 2 isolates differed also in characteristics of rostellar hooks, those from the Montana isolate being fewer and larger, often with accessory hooks.

Alaska↗
PubMed1992

Experimental evaluation of mink and Apodemus speciosus in the Echinococcus multilocularis life-cycle in Hokkaido, Japan.

The epizootiological status of mink (Mustela vison) as definitive hosts and Apodemus speciosus as intermediate hosts in the transmission of Echinococcus multilocularis in Hokkaido, Japan, were evaluated by orally inoculating mink with protoscoleces, and A. speciosus with eggs of the cestode, respectively. No tapeworms were recovered from the alimentary tract of the mink, and no hydatid cysts were recovered from the viscera of the egg-inoculated A. speciosus. We conclude that mink and A. speciosus cannot serve as definitive hosts and intermediate hosts of E. multilocularis, respectively, in Hokkaido.

Animals↗
PubMed1983

Proliferation and metastases formation of larval Echinococcus multilocularis. I. Animal model, macroscopical and histological findings.

Using surgical techniques, 70 Meriones unguiculatus were infected by implantation of 0.15-0.20 g of larval Echinococcus multilocularis tissue into the subcutis of the neck region. In 64 of 65 animals necropsied, the transplants had increased in size and weight and reached an average weight of 4.1 g at the end of the experiment 12 weeks post infection (p.i.). Metastatic Echinococcus lesions developed in the regional lymph nodes and in the lungs; in 18 animals the parasite proliferated into the thoracic cavity. Of 41 animals examined 10 and 12 weeks p.i., 88% had multiple or single metastatic lung lesions, the first being observed 6 weeks p.i. Typical cysts and protrusions ("buds") of the germinal layer were detected in samples of parasite tissue before and after transplantation to experimental animals, as well as in lymph nodes and lungs in which metastases had developed. Similar structures were found in liver sections of two patients with alveolar echinococcosis. It is concluded that the spread of the parasite from the subcutis of the neck region to the draining lymph nodes and the lungs had taken place via the lymph and blood system. The possible role of the "buds" in metastases formation is discussed.

Animals↗
PubMed1989

Application of a recombinant Echinococcus multilocularis antigen in an enzyme-linked immunosorbent assay for immunodiagnosis of human alveolar echinococcosis.

A highly antigenic polypeptide fragment of the recombinant Echinococcus multilocularis antigen II/3 was produced in Escherichia coli and purified for application in enzyme-linked immunosorbent assay (ELISA). The antigen II/3-encoding 1.0 kb DNA sequence was reduced by sonication into smaller DNA fragments which were subsequently cloned into lambda gt11. Three clones could be isolated from the sublibrary, all synthesizing a recombinant antigen as a stable beta-galactosidase fusion protein. In a further step, the 0.6-kb insert from one positive clone was subcloned into the plasmid pAR 3038, which directed efficient synthesis of the antigen fused to only 11 amino acids from the N-terminus of the phage T7 major capsid protein. The plasmid-encoded antigen (antigen II/3-10) was purified from a bacterial cell extract and then tested in an ELISA. Using sera from 88 patients with an E. multilocularis-infection, a high diagnostic sensitivity of 90% was demonstrated. Investigation of sera from 220 patients with various helminthic infections showed a specificity of 99%, suggesting the suitability of the antigen II/3-10 as an immunodiagnostic tool.

Animals↗
PubMed1978

Cellular changes in the lymphoreticular tissues of C57L/J mice infected with Echinococcus multilocularis cysts.

The pathology of the spleen, lymph nodes and thymus of C57L/J mice, infected intraperitoneally with 20 and 100 cysts of Echinococcus multilocularis is described at 2, 4, 8 and 12 weeks postinfection (p.i.). For the first 8 weeks, growth of the larval cyst mass (LCM) was slow and blastogenesis in T-dependent areas of both spleen and lymph nodes was moderate whereas in B-cell compartments it was intense. A rapid growth of the LCM between 8 and 12 weeks p.i., 15-20 times greater than for the first 8 weeks, was associated with depletion of lymphocytes in thymus dependent area (TDA) of both spleen and lymph nodes, gross expansion of the red pulp with extramedullary haemopoiesis, partial atrophy of spleen follicles, but not those of the lymph node, and involution of the thymus. At 12 weeks p.i. the TDA had mainly plasma cells and histiocytes among occasional lymphocytes and blast cells; germinal centre activity and plasmacytosis persisted in B-cell areas. Morphological aspects of these changes are discussed in relation to the invasiveness and proliferation of the LCM during the course of infection.

Animals↗
PubMed1991

Echinococcus multilocularis antigens modify accessory cell function of macrophages.

Peritoneal macrophages and splenic lymphocytes were collected from BALB/c mice, normal or previously infected with Echinococcus multilocularis. In an accessory cell function assay, peritoneal macrophages, in increasing numbers, were added to cultures of splenic lymphocytes. Cultures were stimulated by concanavalin A (Con A) or E. multilocularis culture supernatant (EMSN). Post-infection macrophages, unlike normal macrophages, suppressed Con A- and EMSN-driven lymphocyte transformation. Modification of accessory cells could also be repeatedly induced in vivo by EMSN or a single FPLC fraction of EMSN. Lymphocytes were made more sensitive to accessory cell signals following incubation with EMSN.

Animals↗
PubMed1989

Comparison of albendazole, mebendazole and praziquantel chemotherapy of Echinococcus multilocularis in a gerbil model.

The efficacy of albendazole (50 mg/kg/d), mebendazole (50 mg/kg/d) and praziquantel (500 mg/kg/d) against established intraperitoneal infections of Echinococcus multilocularis in gerbils was compared by monitoring parasite weight and making ultrastructural observations on treated and untreated material. Praziquantel was the most active protoscolicidal agent, reducing protoscolex viability to less than 2%, although it did not inhibit cyst growth. Albendazole was the most effective agent in reducing cyst growth and was, when compared with other regimes significantly more effective than mebendazole (p less than 0.05), praziquantel (p less than 0.01) or untreated controls (p less than 0.01).

Albendazole↗
PubMed2003

Effect of mouse strain variations and cortisone treatment on the establishment and growth of primary Echinococcus multilocularis hydatid cysts.

The main purpose of this study was to determine the effects of cortisone on the number and size of primary Echinococcus multilocularis cysts developing in a moderately resistant strain of mice, i.e., C3H/HeJ. Computerized image analysis was used to measure the surface area occupied by hydatid cysts 10 wk after inoculation of the mice with E. multilocularis eggs. Our second objective was to compare the infectivity of primary E. multilocularis hydatid cysts in C57BL/6J-Ay/a (lethal yellow) mice with that in C57BL/6J-a/a (non-agouti black) mice. The data obtained show no difference between the C3H/HeJ and C57BL/6J-a/a strains of mice; yet, the image analysis method was able to detect a slight increase in the total cyst size within the Ay/a mutant of the C57BL/6J strain. Treatment of C3H/HeJ mice with cortisone drastically increased both the number of cysts and the average size of each cyst when the treatment occurred early in the infection.

Animals↗
PubMed2002

Culture of Echinococcus multilocularis metacestodes: an alternative to animal use.

This article reviews the use of an in vitro culture model for the maintenance and proliferation of Echinococcus multilocularis metacestodes and the formation of protoscoleces. This model has been used to identify and characterize parasite molecules involved in host-parasite interactions, and is a suitable tool to perform in vitro drug-screening assays. The development of a simple and easy-to-handle assay to determine the effects of drugs on parasite viability, without the need for time-consuming animal experimentation, has opened the way for larger-scale in vitro drug screening.

Animal Testing Alternatives↗
PubMed2000

Dose dependency of prednisolone tertiary-butylacetate (PTBA) treatment on the establishment and site predilection of Echinococcus multilocularis in an alternative definitive host model using Mongolian gerbil (Meriones unguiculatus).

Mongolian gerbils (Meriones unguiculatus) were orally inoculated with 10,000 protoscoleces of Echinococcus multilocularis per head after being divided into five groups (A E). Each group was dosed with prednisolone tertiary-butylacetate (PTBA) as follows: A, 0 mg; B, 0.5 mg; C, 2 mg; D, 5 mg; and E, 10 mg/head. All animals were injected subcutaneously with control solvent or PTBA every other day from 6 days pre- to 6 days post-infection. Autopsy was performed at 7 days post-infection. Doses of PTBA and the number of worms recovered showed a positive correlation (r = 0.929, P < 0.0001). In groups A, B and C, the predilection site of the worms in the small intestine could not be determined, while in group D the worms were found more in the anterior part. In group E, the predilection site was the anterior part, followed by the middle and the posterior parts of the small intestine (Fisher's test: P < 0.01). The number of worms recovered from the anterior and the middle part of the small intestine also correlated positively with PTBA dose (anterior part: r = 0.930, P < 0.0001, middle part: r = 0.917, P < 0.0001). All groups of the PTBA-treated animals showed significant loss of weight compared to the nontreated animals (P < 0.01).

Animals↗
PubMed1989

H and 13C n.m.r. studies of serum from normal and Echinococcus multilocularis infected jirds.

The major components of the 13C and high field region of the 1H nuclear magnetic resonance (n.m.r.) spectra of normal and Echinococcus multilocularis infected jirds were identified and compared. Substantial depletion of the glucose and fatty acid chains from lower density lipoproteins was detected in sera from infected animals. In addition, this proliferating metacestode markedly changed the appearance of the spectral region recently assigned to N-acetyl protons of carbohydrate side chains of N-acetylated glycoproteins.

Animals↗
PubMed2006

Characterisation of EmMPK1, an ERK-like MAP kinase from Echinococcus multilocularis which is activated in response to human epidermal growth factor.

Mitogen-activated protein (MAP) kinases are key regulators of cellular signalling systems that mediate responses to a wide variety of extracellular stimuli and should also play a central role in developmental mechanisms of parasitic helminths. Until now, however, no MAP kinase orthologue has been characterised in a member of this parasite group. Here, we report the identification and characterisation of such a molecule, EmMPK1, from the human parasitic cestode Echinococcus multilocularis. Using a degenerative PCR approach, we isolated and completely sequenced the 1.2kb cDNA for EmMPK1 which displays significant homologies to known MAP kinases of different phylogenetic origin. EmMPK1 contains all amino acid residues which are characteristic for MAP kinases, including a conserved TEY motif which identifies the protein as a member of the ERK subfamily of MAP kinases. The corresponding gene, emmpk1 (6.9 kb), was characterised and contained 10 introns. Southern blot hybridisation studies showed that emmpk1 is present as single copy locus in E. multilocularis. Using RT-PCR analyses we demonstrated that emmpk1 is expressed in form of three different transcripts which derive from alternative splice acceptor site utilisation at intron 9. Using EmMPK1-specific antibodies in Western blot studies and immunohistochemistry, we detected the Echinococcus protein and its phosphorylated form in the larval stages metacestode and protoscolex during in vitro cultivation and during an infection of the intermediate host. EmMPK1, immunoprecipitated from Echinococcus lysate, was able to phosphorylate myelin basic protein in activity assays, indicating that it is a functionally active MAP kinase. Finally, we also show that phosphorylation of EmMPK1 is specifically induced in vitro-cultivated E. multilocularis metacestode vesicles in response to exogenous host serum and upon addition of human epidermal growth factor. These data indicate that the E. multilocularis metacestode is able to sense epidermal growth factor from the host which results in an activation of the parasite's MAP kinase cascade.

Alternative Splicing↗