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At least 1,729 records · Page 96Linked to original sources
PubMed1983

Schistosoma mansoni: the effects of a subcurative dose of praziquantel on the ultrastructure of worms in vivo.

The in vivo effects of a subcutaneously-administered subcurative dose (200 mg/kg body weight of mouse) of praziquantel on the structure of Schistosoma mansoni was investigated. Worms were collected at varying times post-treatment and processed for both SEM and TEM examination. Praziquantel caused extensive structural changes to both male and female worms within 15 min of treatment although variations in the amount of drug-induced damaged was observed between male and female worms. In female worms although some tegumental vacuolation was observed within 15 min, the major structural change was an often extensive vacuolisation of the subtegumental tissues followed by varying degrees of structural disruption to the subtegumental and gastrodermal musculature. In male worms the initial effects were a vacuolisation of parts of the dorsal tegument and loss of tegumental cytoplasm due to the pinching off of evaginations of the outer surface. With increasing time post-treatment there was an increase in the amount of tegumental damage, particularly in male worms, with total disruption of parts of the outer surface occurring. Also in male worms there was an increase in the amounts of vacuolisation of the parenchymal tissues and in the degree of structural damage to the musculature. In those female worms where subtegumental damage was not extensive changes in the structure of the differentiating vitelline cells were noted.

Animals↗
PubMed1994

Eucalyptus: a sustainable self-delivery molluscicide?

Attention is drawn to the limitations of conventional methods of controlling important trematode infections such as schistosomosis and fasciolosis. Plant molluscicides could have a role in the future control of these infections. There are, however, major problems with most plant molluscicides in that their use is labour-intensive, in many cases relatively skilled workers are required, they must be applied regularly and arable land may be required for their cultivation. Thus, little progress is to be expected until plant species with sustainable self-delivery systems are identified. Eucalyptus is proposed as a likely candidate. The leaves of many species in this genus have molluscicidal properties and their intermittent fall could effect self-delivery if the trees were planted in appropriate places. Relatively little work has been carried out on this possibility and much more is necessary, especially field trials. Before field trials are started, more laboratory testing is also necessary to determine the LC50 values for different snail species and to study toxicity to non-target organisms.

Animals↗
PubMed1980

ABO aggulutinins from Biomphalari straminea snails.

Extracts from B. straminea spawn are active against A and B normal red cells. A1 and A2 subgroups may be differentiated with trypsin-, papain- and pronase-treated cells. 0 cells treated with papain, pronase and neuraminidase react weakly to the extracts.

ABO Blood-Group System↗
PubMed1994

Oxazole, pyrazole and piperidine derivatives having an o-hydroxyaryl moiety with anticipated molluscicidal activity.

The condensation reactions of hippuric acid and its furyl derivative with salicylaldehydes or that of salicylhippuric acid analogues with furaldehyde led to the corresponding oxazoles. These were subsequently treated with hydrazine hydrate, hydroxylamine or subjected to alkaline hydrolysis to yield new o-hydroxyaryl or salicyl containing derivatives. 5-Substituted salicylanilides were treated with piperidine and formaldehyde in a Mannich type reaction affording the corresponding 3-(N-piperidinomethyl) salicylanilides. It was noticed that the presence of an electron donating group in position 3 in the salicylanilide moiety decreases the molluscicidal activity.

Animals↗
PubMed2002

Synthesis, antimicrobial and molluscicidal activities of new benzimidazole derivatives.

A series of benzimidazole Schiff's bases, thiosemicarbazides were synthesized, azole ring systems as 1,3,4-triazole, 1,3,4-oxadiazole were prepared. 1-Methylbenzimidazole incorporated to substituted dithio-carbamate, thiophenol, diethylamine via acetamido group were synthesized. A series of pyrimidinobenzimidazoles, triazinobenz-imidazoles, and 2-(acetonylamino)-1-methylbenzimidazole were prepared. The antimicrobial and molluscicidal activities of some newly prepared compounds were carried out.

Animals↗
PubMed1997

The Closed Equilibrated Biological Aquatic System: general concept and aspects of botanical research.

The Closed Equilibrated Biological Aquatic System (CEBAS) consists of four subcomponents which form a closed (artificial) aquatic ecosystem initially designed to study the long-term influence of space conditions on several successive generations of aquatic organisms. Teleost fishes and water snails in the zoological component produce CO2 ammonium ions and waste compounds which can be utilized after ammonium is oxidised in a microbial component by the botanical component consisting of a rootless, aquatic higher plant species which eliminates ions, i.e. nitrate, and produces oxygen for animal respiration. An electronic component serves as a data-acquisition and regulation device for temperature and oxygen-dependent illumination of the plant chamber. A comprehensive interdisciplinary research programme, focused around the CEBAS, is especially well developed in the field of zoology. It covers a ground laboratory and preparations for two scheduled space flight projects, as well as aspects of combined animal-plant food production modules for human nutrition in bioregenerative space life-support systems and for terrestrial production sites. In the botanical research programme, morphological investigations on Ceratophyllum demersum L. performed with light and electron microscopy have demonstrated a gas lacuna system which, in addition to starch grains in the plastids, might regulate the buoyancy of the plant and/or serve as a 'gas skeleton'. Also, a remarkable symmetry in the arrangement of tissues was observed in stems and older leaves. The photosynthetic capacities of Ceratophyllum in the CEBAS-MINI MODULE proved to be more than sufficient for life support, and experiments on nitrate uptake into the plants showed their capacity to utilize ions from the water.

Animals↗
PubMed2000

SCID mice show a similar susceptibility to Angiostrongylus cantonensis as do wild-type mice of the C.B-17 strain.

C.B-17-SCID/SCID (SCID) mice infected with Angiostrongylus cantonensis yielded a high percentage of worm recovery and did not show any body weight loss until day 24 postinfection. Unexpectedly, C.B-17-+/+(+/+) mice also produced a similar worm burden containing well-developed worms. This is probably attributable to the observation that +/+ mice failed to induce eosinophilia in cerebrospinal fluid (CSF) despite their production of antigen-specific IgA and IgGI; +/+ mice have defective bone-marrow eosinopoiesis, which in turn results in reduced blood and CSF eosinophilia. Interleukin 5 (IL-5) production in +/+ mice is similar to that in BALB/c and C57BL/6 mice. However, bone-marrow eosinopoiesis in response to IL-5 is markedly suppressed in +/+ mice. This is probably associated with impaired expression of common beta-chain mRNA in bone-marrow cells of +/+ mice, which leads to the failure of bone-marrow eosinopoiesis. Hence, +/+ mice may serve as a useful model for the elucidation of eosinophil production in the mouse and for determination of the relationship between parasite infection and the eosinophil.

Angiostrongylus cantonensis↗
PubMed1997

Assessment of the viability of Schistosoma mansoni schistosomula by comparative uptake of various vital dyes.

Of various vital dyes used to assess schistosomula viability, toluidine blue enabled differential counting of the schistosomula on microscope slides but not in culture wells, whereas methylene blue could be added directly to the schistosomula suspension in culture wells of microtiter plates. Toluidine blue uptake by dead parasites was very fast. It mostly also partially stained damaged but not dead organisms. Its main disadvantage was rapid, nonspecific staining of live schistosomula, requiring prompt counting of a preparation and additional reliance on motility for assessment of viability. Methylene blue staining of dead worms was slower, but it did not stain the live worms until about 1 h after dye application, enabling its addition to a series of preparations for consecutive counting. It did not always stain flattened, dead schistosomula or it stained them an uncontrasting pale blue. This dye remarkably induced movement in seemingly inert and probably damaged worms, thus enabling determination of viability even following poor staining or a lack of staining.

Animals↗
PubMed1999

Host-parasite relationships between Echinostoma caproni and RAG-2-deficient mice.

The RAG-2-deficient mouse, a strain of genetically altered mice lacking B- and T-lymphocytes, was used as a host for Echinostoma caproni. In all, 12 male RAG mice were exposed to 25 cysts each, and 12 served as uninfected controls. Mice were necropsied at 2 and 3 weeks postinfection (p.i.). The mean number+/-SE (9.7+/-2.4) of worms recovered from infected mice at 2 weeks p.i. was not significantly different from that recovered at 3 weeks p.i. (6.5+/-2.2). The intestinal circumference of infected RAG mice was significantly greater than that of the controls at 2 and 3 weeks p.i. A significant goblet cell hyperplasia occurred at 2 weeks p.i., but the response was not effective in eliminating worms from the RAG mice. The effect of a high cyst burden was examined by exposure of 8 RAG and 8 ICR mice to 100 cysts each. The body length and area and the oral sucker area of worms grown in RAG mice were significantly greater than those of worms grown in ICR mice. Worm recovery at up to 3 months p.i. was examined in RAG mice exposed to 25 cysts and necropsied every 2 weeks p.i. The mean worm recovery recorded at 2 weeks p.i. was significantly greater than that noted at 12 weeks p.i., at which time worm rejection from the RAG mouse host first occurred. The RAG mouse is a useful host for studies on E. caproni in a murine host that lacks B- and T-lymphocytes.

Animals↗