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P H De Rycke

Publications and source records attributed to P H De Rycke.

At least 19 recordsLinked to original sources
PubMed1997

Immunomodulation by hydatid cyst fluid toxin (Echinococcus granulosus).

Since the experimental infection by hydatid cysts (Echinococcus granulosus) in mice causes immunomodulation of the host, the effects of hydatid fluid (HF) and fractions of HF were compared in vitro and in vivo. Fractions of HF were obtained using ammonium sulphate precipitation, chloroform/methanol extraction and thin-layer chromatography (TLC). HF proved to be toxic to murine peritoneal macrophages in vitro, and when macrophages were incubated with the different fractions of HF, most toxicity was found in a single TLC-purified fraction with an adjuvant-like effect on the production of specific antibodies against bovine albumin and human red blood cells in mice. Treatment of mice with the toxin caused a drop in the percentage of peripheral blood lymphocytes. Flow-cytometric analysis showed that T-cells from toxin-treated mice had lower membrane-CD3, CD4 and CD8 density, and higher percentages of CD8+ splenocytes and CD4+ thymocytes expressing CD25. The toxin caused a down-regulation of CD4 and CD8 expression on thymocytes in vitro, that was dependent on the presence of macrophages. The results may attribute to these toxins a role in the host-parasite relationship of hydatidosis.

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PubMed1995

Changes in T-cell subpopulations in mice during prolonged experimental secondary infection with Echinococcus granulosus.

Balb/c mice were infected intraperitoneally with protoscoleces of Echinococcus granulosus. After 15 months of infection, and by means of flow cytometry, the expression of T-cell markers CD3, CD4, and CD8 on T cells from peripheral blood, spleen, and thymus was analyzed and compared with that of age-matched controls. Infected mice had higher percentages of CD3+, and CD4+ cells in peripheral blood, and higher percentages of CD8+ cells in the spleen, when compared with control mice. CD4+ and CD8+ cells in peripheral blood and CD8+ cells in thymus also showed higher percentages of expression of interleukin-2 receptor. The results infer a role for interleukin-2 in experimental secondary echinococcosis.

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PubMed1993

Dose-dependent effects of hydatid fluid toxins from Echinococcus granulosus on mouse peritoneal macrophages.

Hydatid fluid (HF) from hydatid cysts of the cestode Echinococcus granulosus inhibited the phagocytosis of bacteria and yeast cells by host macrophages in vitro. Different assays were used to study the dose-dependent effect of partially purified HF toxins on peritoneal macrophages (PM phi) of the mouse. Trypan blue exclusion, as well as measuring the specific release of lactate dehydrogenase activity and 51Cr release of 51Cr-labelled PM phi, showed that incubation with HF toxins lead to the lysis of the target cells. By measuring the effect of the toxins on the reduction of 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide by PM phi, and by experimental labelling using [3H]-uridine, a decrease in metabolic activity was seen. However, at non-lytic concentrations, the PM phi showed a peak of metabolic activity. The observations of the effects on macrophages by parasite-derived toxins may be related to a mechanism by which the parasite survives within an immunized host.

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PubMed1991

The immunohomeostatic role of hydatid cyst toxins (Echinococcus granulosus).

It is obvious that during the evolution of a host-parasite relationship, in which one animal is needing the other, while the latter is trying to expel or destroy the former, both partners tend to reach an equilibrium. In many cases they are still far off, but in hydatidosis (Echinococcus granulosus) it would appear that a lot has been achieved. As the near equilibrium is mainly related to the state of the immunological relationship, it is in fact a case of immunohomeostasis. The immunological reactions of the host involve both humoral and cellular phenomena. The nature of the humoral response varies greatly according to host species, parasite strain and several factors of the infection and analysis procedures. The cell-mediated defense mechanism involves various types of cells, but activated macrophages appear to be most important. With regards to the modes of immunoevasion, attention is paid to the barrier role of the laminated layer, the inactivation of complement and the interference with the activities of host immune cells. The role of toxic substances released by protoscoleces and cysts is especially emphasized. The toxins appear extremely vulnerable to host macrophages and play a very important role in the establishment of a hydatid cyst. However, they have only a local influence and do not jeopardize the development of concomitant immunity. Observations in experimental secondary echinococcosis led to the conclusion that the establishment of a hydatid cyst depends on the speed of the parasite's toxic effect versus the host immunological reaction. Survival of the parasite is based on the continued balancing effects of both.

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PubMed1990

Development of larval Echinococcus granulosus confronted with chicken heart tissue in vitro.

Vesiculated protoscoleces (VP) were produced by culturing freshly collected protoscoleces from Echinococcus granulosus horse liver hydatids in RPMI 1640 monophasic medium at 37 degrees C for 18 days. Half of the VP were used as such, the other half used after killing them by freeze-thawing. Nine-day-old chicken heart fragments (CHF) were cultured in MEM at 37 degrees C for 72 h. Subsequently, CHF were put together with live and dead VP, respectively, for up to 53 days, on a semisolid medium consisting of agar, Ringer's and MEM. Time-dependent histological observations revealed that dead VP were surrounded by CHF cells. Dead VP tissue was eventually internalized and disintegrated in about 1 week. Live VP penetrated into the CHF tissue and further developed into small hydatid cysts, located within the boundaries of the experimental 'host' tissue. The amorphous-looking contact region PAP-stained positively only with anti-E. granulosus serum and not with anti-CHF serum; it was considered identical to the normal laminated layer. The invasion of VP in CHF tissue proved to be different from a tumour or a bacterial invasion: it was concluded that the confrontation of VP and CHF had resulted in an 'in vitro cohabitation' rather than in an 'in vitro infection'.

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PubMed1990

Hymenolepis diminuta: intestinal mast cell and eosinophil response of the mouse to infection.

It has been demonstrated that the rejection of Hymenolepis diminuta by the mouse is characterized by a humoral response in serum and intestinal lavage. Now the response is also shown to be accompanied by a mast cell and eosinophil response in the lamina propria of the intestine. The mast cell response is, in time and place, correlated with the rejection process of H. diminuta. With regard to the number of eosinophils in the lamina propria, a significant response was only found in the second half of the intestine. The eosinophil peroxidase (EPO) concentration in the intestinal lumen is correlated with the rejection of the parasite and illustrates the involvement of eosinophils in the rejection process. The course of the EPO response is identical to the mast cell response. This, together with other results, suggests that, as to other "systemic" worm infections, a mast cell-eosinophil response may be, at least in part, responsible for the rejection of H. diminuta from the intestinal lumen.

Animals↗
PubMed1990

Hydatidosis in Belgium: analysis of larval Echinococcus granulosus by SDS-PAGE and western blotting.

Echinococcosis/hydatidosis is characterized by the existence of various strains of the parasite Echinococcus granulosus. In order to study the degree of variability in Belgium, protoscoleces (PS) were isolated from infected intermediate hosts (horse, cattle, pig, goat and man). Homogenate supernatants of these PS were compared by SDS-polyacrylamide gel electrophoresis and western blotting: 15 to 26 predominantly silver staining bands (depending on the source of the parasites), were selected to study existing homologies among these possible strains. Antisera raised against PS homogenates of horse, cattle, pig and goat origin, were used to compare antigenicity by western blotting. The results indicate a closer similarity between E. granulosus of horse, goat and pig origin whereas E. granulosus derived from cattle showed less homology with any of the former. Results are discussed against the background of the occurrence of E. granulosus in Belgium.

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PubMed1989

Hymenolepis murissylvatici: humoral response in intestinal lavages of the mouse.

Hymenolepis murissylvatici elicits a humoral response in serum and in the intestine of the mouse from which it is immunologically rejected. In serum, significant differences were recorded 3 days after reinfection, while in intestinal lavages it takes place from day 9 after reinfection. In serum the response is largely the result of IgG and IgM antibodies whereas in the intestine, IgA is the most abundant antibody. Although specific IgE could not be demonstrated in serum, it was present in intestinal lavages, although rather late (i.e. day 14 after reinfection). Treatment of young worms in vitro both with immune serum or intestinal lavages had no apparent effect on their viability. Immune serum produced a complement independent precipitation on the surface of the worms in vitro. This reaction did not affect viability or infectivity of the parasite, as demonstrated by the successful implantation of treated worms in recipient mice. The above-mentioned results, together with the knowledge that the Hymenolepis model has no tissue stages and causes no tissue damage, make it probable that further study of this model will reveal some specific intestinal immunological reactions.

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PubMed1988

Changes in naloxone and haloperidol effects during the development of captivity-induced jumping stereotypy in bank voles.

Captivity-induced stereotypies in bank voles (Clethrionomys glareolus) were inhibited at the age of 1, 2, 4, 6, 8 and 10 months by 0.2 mg/kg haloperidol s.c., while 35 mg/kg naloxone s.c. only inhibited them at the age of 4-6 months. Other activities were not significantly inhibited. The change in the naloxone effect was not due to desensitization as animals treated only at 6 or 8 months reacted similarly. It is suggested that the expression of such stereotypies is influenced by endogeneous brain opioid peptides during an early stage of their development, but that thereafter only motoric automatisms remain, essentially under dopaminergic control.

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PubMed1988

Hymenolepis muris-sylvaticae and H. microstoma: immunological cross-reaction in mice.

A primary infection with Hymenolepis microstoma strongly protects against cross-infection with H. muris-sylvaticae and also against secondary infection with H. microstoma in NMRI mice, resulting in an accelerated loss of worms and a weight reduction of the remaining worms. A primary infection with H. muris-sylvaticae causes an accelerated rejection of secondary infection with H. muris-sylvaticae but it has no effect on cross-infection with H. microstoma, neither with regard to worm recovery nor with regard to worm biomass. Determinations by enzyme-linked immunosorbent assay of antibody concentrations in the mouse sera revealed that: (1) the antibody response evoked by H. microstoma infection is much greater than by H. muris-sylvaticae infection; (2) a cross-infection with H. muris-sylvaticae boosts the antibody response evoked by H. microstoma infection; (3) H. microstoma antigen can be used to measure antibody concentration against both H. microstoma and H. muris-sylvaticae; and (4) although H. muris-sylvaticae is rejected faster in a cross-infection (i.e., after a primary H. microstoma infection) than in a secondary infection (i.e., after a primary H. muris-sylvaticae infection), antibodies evoked by the primary H. microstoma infection show little cross-reaction with H. muris-sylvaticae antigen. This suggests that it is doubtful whether serum antibodies are the direct effectors in worm rejection.

Animals↗
PubMed1987

The effect of interference in catecholamine biosynthesis on captivity-induced jumping stereotypy in bank voles (Clethrionomys glareolus).

The level of the captivity-induced jumping stereotypy in bank voles was significantly decreased by 150 and 200 mg/kg alpha-methyl-para-tyrosine and increased by 200 mg/kg L-DOPA while 20 and 40 mg/kg fusaric acid had no effect. None of the other movements were affected by these drugs (as measured by a general activity meter), except for a nonsignificant decrease after treatment with fusaric acid. These results suggest that cerebral dopaminergic neuronal systems and not noradrenergic neuronal systems are involved in the expression of that stereotypy in bank voles.

Animals↗
PubMed1986

Immunological aspects in the rejection process of Hymenolepis muris-sylvaticae from CFLP and NMRI mice.

When mice were treated with 1.25 mg cortisone acetate thrice weekly, recovery of Hymenolepis muris-sylvaticae was significantly higher than in untreated controls, both in oral infections with six cysticercoids and surgical transplantations of one 7-day or 8-day-old worm. Cortisone treatment also resulted in the worms being located more anteriorly in the small intestine. Evidence of an immunological response against the tapeworm in the intestine is given by: an accelerated rejection of a secondary oral cysticercoid infection and a significant difference of the dry weights of the worms recovered on day 10 in CFLP mice; an accelerated rejection of a secondary surgical infection on days 4 and 6 in CFLP mice and on days 3 and 4 in NMRI mice; an accelerated rejection of a secondary surgical infection given 3 and 6 months after the primary immunizing infection in SWISS-albino mice.

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PubMed1984

Hymenolepis muris-sylvaticae in laboratory rodents.

The establishment, growth, survival and distribution of Hymenolepis muris-sylvaticae in different laboratory animals (Wistar rats, golden hamsters, CFLP and NMRI mice) after oral infection and surgical transplantation were determined. Worms that establish in CFLP and NMRI mice grow exponentially but are rejected at different times p.i. depending on the strain of mice and mode of infection. Only in golden hamsters will H. muris-sylvaticae develop to a mature worm; in rats there is no growth at all. Worms of all sizes are found in the posterior half of the small intestine in rats and both strains of mice; in hamsters the worms are recovered more anteriorly.

Animals↗
PubMed1978

Serial passages of larval Echinococcus granulosus from equine origin in mice. III. Infections with sterile daughter cysts.

Daughter cysts 0.2-3.0 mm in diameter from secondary Echinococcus granulosus cysts, collected from mice one year after experimental infection, were transferred to fresh mice. The metacestodes developed into larger cysts showing fertility and daughter cyst formation at autopsy 9-14 months post infection. The average total growth of all cysts per mouse expressed in log weight (mg) amounted to 0.25 +/- 0.03 per month. Thus, for the maintenance of the parasite in mice, daughter cysts can be used as successfully as protoscolices and small 'latent' cysts.

Animals↗
PubMed1978

Serial passages of larval Echinococcus granulosus from equine origin in mice. II. Infections with sterile cysts.

Sterile secondary E. granulosus cysts less than or equal to 1 mm in diameter, collected from mice 6-13 months after experimental infection were transferred to helminth-free mice. They developed into larger cysts showing fertility and daughter cyst formation at autopsy 9--14 months p.i. Average growth of the largest cyst per mouse, expressed in log volume (microliter), amounted to 0.30 +/- 0.03 per month; average growth of all cysts per mouse, expressed in log weight (mg) amounted to 0.27 +/- 0.02 per month. An inversed ratio was found between total parasite weight and number of cysts injected. The practical importance of these observations is discussed.

Animals↗
PubMed1978

Serial passages of larval Echinococcus granulosus from equine origin in mice. I. Infection with protoscolices.

Starting with protoscolices from Echinococcus granulosus cysts of equine origin it was possible to isolate and maintain several "strains" of the parasite in mice through successive transfers of protoscolices. The most advanced strain is now in its 7th generation. Several criteria to evaluate the results are presented and discussed. It is concluded that serial echinococcosis of E. granulosus through passages with protoscolices is a practical method to maintain different strains for fundamental and applied comparative studies.

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