Abstract
AdultHymenolepis diminuta, H. microstoma, H. nana, Echinococcus multilocularis, andTaenia (Hydatigera)taeniaeformis have been exposed in vitro in media containing 0.1 to 100 μg praziquantel/ml. Already after 5 min characteristic tegumental lesions, that were restricted to the growth zone of the neck region, were recognized using both scanning and transmission electron microscopy. Within the tegument numerous vacuoles were formed that released their contents to the exterior and finally caused destruction of the tegument. Proglottides of the central or posterior strobilar portions were never damaged.
Larvae ofT. taeniaeformis (cysticerci) andE. multilocularis (alveolar cysts) were studied employing the same methods both after in vitro exposure to and after in vivo treatment of their hosts with praziquantel. Strobilocerci ofT. taeniaeformis developed identical tegumental lesions after contact with praziquantel whether incubated in vitro or treated in vivo. The wall of the bladder containing the larva remained unaffected. Evaginated protoscolices ofE. multilocularis were damaged by in vitro contact with praziquantel while invaginated protoscolices remained intact. After in vivo exposure there were some fully developed evaginated and damaged protoscolices whereas all invaginated protoscolices and the cyst wall with its germinative layer were unaffected.
Zusammenfassung
AdulteHymenolepis diminuta, H. microstoma, H. nana, Echinococcus multilocularis undTaenia (Hydatigera)taeniaeformis wurden in vitro in Medien inkubiert, die 0,1–100 μg Praziquantel/ml enthielten. Mit Hilfe der Scanning-und der Transmissionselektronenmikroskopie konnten charakteristische Schäden des Teguments ausschließlich im Bereich der Sprossungszone schon nach 5 min nachgewiesen werden. Es entstanden hier zahlreiche Vakuolen, die ihren Inhalt nach außen abgaben und so schließlich das Tegument zerstörten. Proglottiden der mittleren und hinteren Strobilaabschnitte wurden niemals derartig geschädigt.
Larven vonT. taeniaeformis (Strobilocercen) undE. multilocularis (alveoläre Cysten) wurden mit den gleichen Methoden in vitro sowie nach in vivo-Behandlung in ihren Wirten untersucht. Es zeigte sich, daß der Strobilocercus vonT. taeniaeformis sowohl nach Inkubation in vitro wie nach in vivo-Behandlung mit Praziquantel gleichartige charakteristische Schäden aufwies, die umhüllende Blasenwand allerdings niemals. BeiE. multilocularis ergab sich, daß bereits evaginierte Protoscolices in vitro geschädigt wurden, nicht dagegen die invaginierten Protoscolices.
In vivo wurden einige voll entwickelte evaginierte und geschädigte Protoscolices gefunden, während die invaginierten und die Brutkapsel mit dem Keimepithel offenbar intakt blieben.
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Abbreviations
- B:
-
Bubbles
- BL:
-
Basement layer
- CM:
-
Circular musculature
- LM:
-
Longitudinal musculature
- M:
-
Microtriches
- MI:
-
Mitochondria
- P:
-
Proglottis
- R:
-
Rostellum
- S:
-
Sucker
- SC:
-
Scolex
- SEM:
-
Scanning electron microscopy
- TD:
-
Tegumentary disks
- TEM:
-
Transmission electron microscopy
- TG:
-
Tegument
- TGC:
-
Tegumental cell
- V:
-
Vacuoles
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Becker, B., Mehlhorn, H., Andrews, P. et al. Ultrastructural investigations on the effect of praziquantel on the tegument of five species of cestodes. Z. Parasitenkd. 64, 257–269 (1981). https://doi.org/10.1007/BF00927373
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DOI: https://doi.org/10.1007/BF00927373