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Biomedical subjects

O Vanparijs

Publications and source records attributed to O Vanparijs.

At least 37 records · Page 2Linked to original sources
PubMed1988

In vivo action of the anticoccidial diclazuril (Clinacox) on the developmental stages of Eimeria tenella: an ultrastructural evaluation.

A single 5-mg/kg oral dose of diclazuril affected both the asexual and sexual development of Eimeria tenella in experimentally inoculated chickens. In second-generation schizonts, early growth and nuclear divisions progressed normally, but a marked inhibition of merozoite formation was observed. Exogenesis of merozoites was largely prevented, whereas production of micronemes, amylopectin granules, and dense bodies and the formation of rhoptries, conoid, and pellicle continued. All these subcellular organelles accumulated, together with differentiated nuclei, within the main cytoplasmic mass. In the end, complete necrosis of the schizonts occurred. In macrogamonts, dilation of the rough endoplasmic reticulum around type II wall-forming bodies, fusion of type II wall-forming body contents, disturbance of the normal parallel arrangement of rough endoplasmic reticulum, and disruption of row formation of amylopectin granules became evident. In the microgamonts, normal evagination of microgametes was prevented; the flagellar complex formed within the main cytoplasmic mass and the differentiated nuclei remained present within the parasite body. The macro- and microgamonts also ended up in a stage of complete necrosis. These data indicate that diclazuril treatment primarily affects the normal differentiation of the respective endogenous stages during parasite development. This leads to complete degeneration of schizonts and gamonts indicating the lethal effect of this new anticoccidial compound.

Animals↗
PubMed1988

Action of the anticoccidial clazuril on the endogenous stages of Eimeria labbeana and E columbarum in experimentally infected pigeons.

Racing pigeons were artificially infected with a mixed inoculum of Eimeria labbeana (85 per cent) and E columbarum (15 per cent) and treated orally with 2.5 mg clazuril either on day 1, 2, 3, 4, 5, 6 or 7 after infection. The impact of the treatment on the different developmental stages was evaluated by oocyst output and by histological examination of the duodenum and jejunum. The life cycle always became completely interrupted, but maximal effects were noted when treatment was given on day 4, 5 or 6 after infection. Treatment during patency completely interrupted oocyst excretion within three days after dosing. Degenerative changes in schizonts and gametocytes were always observed. The histology revealed a reduced number and abnormal structure of developing merozoites; a ballooned aspect and presence of numerous small vacuoles in the microgametocytes; the absence of typical wall-forming bodies in macrogametocytes and a complete absence of oocysts. It is concluded that clazuril has a coccidiocidal effect on the asexual and sexual developmental stages of both Eimeria species, resulting in a complete interruption of the life cycle.

Acetonitriles↗
PubMed1988

Flukicidal action of closantel against immature and mature Fasciola hepatica in experimentally infected rats and sheep.

The relative importance of peak level- and residual level-related flukicidal activity of closantel against immature and mature Fasciola hepatica was evaluated in a comparative efficacy trial using two animal species with a different plasma elimination pattern, that is, the rat and the sheep with an elimination half-life of less than one week and of two to three weeks, respectively. The rats were dosed orally with closantel at 20 mg kg-1 at two, four, six, eight and 10 weeks; the sheep at 10 mg kg-1 at eight, 10 and 12 weeks after artificial infection. Necropsy was performed either one week after treatment or 12 weeks after infection. Efficacy rates and the length of the recovered flukes were evaluated. It was demonstrated that the flukicidal effect of closantel is directly related to its peak plasma levels and less to its residual plasma concentrations. In the rat, a high efficacy (P less than 0.001) could be demonstrated against immature stages of four weeks or older. The two-week immature stages were less markedly affected. No significant differences in efficacy and size of the flukes were noted between the animals autopsied one week after treatment and those autopsied 12 weeks after infection. In the sheep, the efficacy against six-week and eight-week-old immature stages varied between 70.3 and 76.8 per cent and between 92.8 and 96.5 per cent, respectively. As in the rats, no marked differences in efficacy were noted between the animals autopsied one week after treatment and those autopsied 12 weeks after infection.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Chemotherapy of experimental echinococcosis in mice.

Mebendazole and flubendazole, administered in food at 500 ppm for 14 consecutive days, had a marked effect on one-year-old hydatid cysts of Echinococcus granulosus in mice infected with protoscolices of human origin. In both treated groups most of the cysts were collapsed compared with none in the controls. A small number of apparently viable cysts was observed in both mebendazole and flubendazole treated mice. Histological examination of collapsed cysts revealed necrosis and limited inflammatory infiltration, but in one intact cyst a normal germinal layer was present. The body weight decrease of the treated mice, as the cysts collapsed, was interpreted as an excellent indicator of drug efficacy. Drug-related side effects were not observed.

Animals↗
PubMed1985

Anthelmintic efficacy of flubendazole paste against nematodes and cestodes in dogs and cats.

Small dogs and cats, naturally infected with nematodes and cestodes, were used in a critical test under laboratory conditions to determine the palatability and efficacy of flubendazole as a past formulation. Subsequently, a control test in dogs was conducted under field conditions. A 4.4% past formulation was given at a dosage of 22 mg/kg of body weight once a day for 2 or 3 consecutive days. In a critical test in dogs, the efficacy against Toxocara canis was 97.4% after a 2-day administration and 100% after 3 days. Toxascaris leonina seemed to be the most susceptible worm species, since either 2 or 3 treatments were 100% active. The efficacy against Uncinaria stenocephala was 97.5% after 2 treatments; the same dose level for 3 days improved the efficacy to 100%. The efficacy was 100% for the removal of Trichuris vulpis after a daily dosage for 2 days and 96.7% after 3 days. One of 2 dogs infected with Taenia pisiformis was cleared of the infection after a 2-day treatment, and 3 of 4 dogs were cleared after a 3-day regimen. All cats were cleared of Toxocara cati after 2 or 3 days of treatment. One of 2 cats infected with Hydatigera taeniaeformis was cleared of the infection after a 2-day treatment; a 3-day treatment in 7 cats was 100% effective. The results in the laboratory test in dogs were confirmed under field conditions by a control test, based on the reduction of eggs per gram of feces count after treatment. The paste formulation was well accepted by all dogs and cats without any side effects.

Administration, Oral↗
PubMed1982

Treatment of Trichuris suis infections in pigs with flubendazole.

A severe outbreak of Trichuris suis infection in piglets is described. Fifteen per cent of the animals died and the morbidity, characterised by weight loss and diarrhoea, was over 50 per cent. The severity of symptoms observed in naturally infected pigs was related to the number of whipworms. A chemotherapeutic trial was worked out with flubendazole mixed in food for naturally infected and artificially infected piglets. Flubendazole at 30 ppm for five consecutive days controlled the infection in the pigs. Immature T suis in artificially infected pigs were also controlled at the same dose administered for 10 consecutive days.

Administration, Oral↗
PubMed1978

Oxatomide protects Trichinella spiralis infected mice from lethal anaphylaxis.

Infection with Trichinella spiralis in mice was accompanied by allergic sensitization as evidenced by anaphylactic death after intravenous injection of the antigen. Pre-treatment of the animals with oxatomide, a new orally active anti-allergic drug, resulted in significant protection of the animals; the lowest effective dose of the compound was 1.25 mg/kg orally. In contrast to cyproheptadine, oxatomide offered little protection against serotonin toxicity in mice. The present data suggest that, in this model of systemic hypersensitivity, the anti-anaphylactic effect of oxatomide can be attributed mainly to inhibition of release of allergic mediators.

Anaphylaxis↗
PubMed1978

Scanning electron microscopic observations of Cysticercus fasciolaris (=Taenia taeniaeformis) after treatment of mice with mebendazole.

The time-related topographical changes in mature cysticerci of Taenia taeniaformis induced after medication of infected mice with 250 ppm of mebendazole are described. The changes included the gradual disappearance of microtriches and progressive degeneration of the tegment resulting in an irregular surface with grooves, holes, and craterlike structures. Host cells adhered to the altered areas and the number of these cells increased when more severe changes became apparent. Finally the necrotized cysticerci, which lost their tegument completely, were almost entirely covered with adhesive host cells. A difference in the time sequence of the reported changes occurred between the scolex, the pseudoproglottids, and the bladder. This difference in susceptibility towards the drug between the three parts of the parasite in relation to the morphology of their microtrichous covering is discussed.

Animals↗
PubMed1977

[Toxocariasis in calves. Recent diagnosis and treatment (author's transl)].

Toxocara vitulorum, a parasite of suckling calves, was again diagnosed in Belgium in imported cattle of French origin. The infectious larvae are present in the milk and colostrum; they do not undergo further migration in the tissues of calves. This form of transmammary migration is not specific of T. vitulorum, but was also reported in S. ransomi in pigs. Treatment with levamisole at a dosage of 5 mg/kg results in complete disappearance of the worms. In addition to the cycles, the elements of a specific parasitological diagnosis are also described.

Animals↗
PubMed1975

Morphological changes in cysticerci of Taenia taeniaeformis after mebendazole treatment.

The progressive micromorphological changes in Taenia taeniaeformis cysticerci, induced by a single parenteral treatment of the infected mice with mebendazole, are described. The time-related alterations concerned the tegument and tegumental cells and were successively: disappearance of microtubules, accumulation of secretory substances in the Golgi areas, decrease in number to complete loss of microtriches, "ballooning" of all tegumental cells with subsequent burst, vacuolization and degeneration of the tegument, and finally necrosis of the pseudoproglottids. Similar but less pronounced injuries were seen in the scolices, although microtubules disappeared as early as in the pseudoproglottids. Microtubules from the host tissues remained intact. The meaning of the apparent primary interference of mebendazole with the microtubular system in relation to the subsequently observed death of the cysticercoids is discussed.

Animals↗