Mode of Action of Antitrematodal Agents

Bennett, James L.; Thompson, David P.

doi:10.1007/978-1-4684-1233-8_21

Cited by 10 publications

(5 citation statements)

References 79 publications

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“…In one patient where living worms were shown to be affected by treatment with TCZ, US demonstrated that it took 4 days until most parasites ceased to move completely. This interval is consistent with the time taken for the transformation of TCZ to its pharmacologically active metabolites and their subsequent absorbtion by the parasite ( Bennett et al . 1986 ).…”

Section: Discussionsupporting

confidence: 86%

Fascioliasis: sonographic abnormalities of the biliary tract and evolution after treatment with triclabendazole

Richter

Freise

Mull

et al. 1999

Tropical Med Int Health

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SummaryDiagnosis of infection with the liver fluke Fasciola hepatica is usually difficult. Ultrasonography (US) might be a useful diagnostic alternative, and we assessed the value of sequential US in the diagnosis and monitoring of fascioliasis in 76 patients at baseline and for 60 days after treatment with triclabendazole. At baseline, biliary abnormalities were observed in 52 patients. Crescent-shaped parasites were seen in 11 patients; in 2 cases parasites were spontaneously moving and in 4 patients parasites were motionless. Postprandial examination revealed parasites adhering to the gallbladder wall in a further 5 cases. In 3 further cases, gallbladder contents were mobile but did not sediment downwards after patients changed position. Non-specific abnormalities were: impaired gallbladder contractility (n ϭ 23), gallbladder tenderness (n ϭ 19), debris (n ϭ 6), calculi (n ϭ 5), wall thickening (n ϭ 2) and bile duct dilatation (n ϭ 12). During day 1-7, Fasciola-like crescents in the gallbladder or passing through the bile duct were detected in another 15 patients, impaired gallbladder contractility in 16, gallbladder tenderness in 16, and bile duct dilatation in an additional 28 patients. Thirty-two patients with these US abnormalities experienced colic-like abdominal pain accompanied by increased alkaline phosphatase in 25 cases. During day 30-60, abnormalities regressed completely in 45 patients; 2/6 triclabendazole failures were evident by detection of living parasites. Biliary tract abnormalities are frequently observed by US, but the detection-rate of Fasciola hepatica is disappointingly low despite the parasite's relatively large size. US findings must therefore be interpreted together with other clinical measurements. The visualization of parasites being expelled through the dilated common bile duct allowed the causal interpretation of post-therapeutic abdominal pain and increase of liver enzymes. When triclabendazole is given on suspicion, visualization of worm expulsion and bile duct dilatation by US may be used to confirm diagnosis.

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Section: Discussionsupporting

confidence: 86%

Fascioliasis: sonographic abnormalities of the biliary tract and evolution after treatment with triclabendazole

Richter

Freise

Mull

et al. 1999

Tropical Med Int Health

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“…The benzimidazoles (BZ) are broad-spectrum anthelmintics first recognized over 25 years ago by Brown, Matzuk, lives, Peterson, Harris, Sarett, Egerton, Yakstis, Campbell & Cuckler (1961) and now available in many different forms. Their mode of anthelmintic action appears to be generally similar and involves a number of potential targets including microtubule assembly, fumarate reductase and glucose transport (reviewed by Van den Bossche, 1986;Bennett & Thompson, 1986;Rew & Fetterer, 1986). There is good evidence that BZ can affect microtubule production in helminths; however, Van den Bossche (1986) stressed that it is not possible to determine whether the action of these drugs on microtubules or on energy-producing systems represents their primary anthelmintic mode of action.…”

Section: Anthelmintic Drugs Benzimidazolesmentioning

confidence: 99%

“…Of the currently available anthelmintic drugs that exert significant effects at the parasite surface praziquantel (PZ) has claimed a substantial position in centre stage. The proposed targets for PZ, a broad-spectrum and highly efficacious anthelmintic, are thought to be the parasite musculature and tegument (Gonnert & Andrews, 1977;Rew, 1978;Harder, Andrews & Thomas, 1987a, b;Fetterer, Pax, Thompson, Bricker & Bennett, 1980;Andrews, Thomas, Pohlke & Seubert, 1983;Andrews, 1985;Bennett & Thompson, 1986). Digeneans and cestodes exposed to PZ develop an almost instantaneous tetanic contraction of the musculature and a concurrent and rapid vacuolization of the tegument; in schistosomes the latter event occurs within 30 sec of exposure to therapeutic levels of PZ in vitro and within 15 min in vivo.…”

Section: Praziquantelmentioning

confidence: 99%

The interactions between drugs and the parasite surface

Chappell

1988

Parasitology

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SUMMARYThe interrelationships between drugs and parasite surfaces are considered under the headings of (a) effects on membrane transport, (b) drug uptake mechanisms and (c) effects on surface morphology and function: praziquantel is discussed under a separate heading. The range of chemotherapeutic compounds that cause permeability changes and concomitant morphological disruption is discussed in terms of mode of drug action. Interpretation of the available data renders it difficult to identify the primary mode of action in the drugs considered. Drug uptake mechanisms are known for relatively few compounds; drug resistance as a function of drug acquisition is discussed. The role of the parasite surface as a specific drug target is argued.

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“…Anthelmintics exert their chemotherapeutic effect by interfering with some biochemical or physiological process(es) essential for the survival of the parasite in the host [ 1 ]. Several substituted benzimidazoles [ 2 , 3 ] and benzothiazoles [ 2 , 3 , 4 , 5 ] have been identified as potent anthelmintic drugs.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and in vitro Evaluation of New Benzothiazole Derivatives as Schistosomicidal Agents

et al. 2007

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A series of benzothiazol-2-yl-dithiocarbamates 3a-d along with their copper complexes 4a-c were synthesized via the reaction of suitable alkyl, aralkyl or heteroaryl halides with the sodium salt of benzothiazol-2-yl-dithiocarbamic acid, followed by complexation with copper sulphate. N-(4-Acetyl-5-aryl-4,5-dihydro-1,3,4-thiadiazol-2-yl)-N-benzothiazol-2-yl-acetamides 7a-c were synthesized by cyclization of the appropriate thiosemicarbazones 6a-c in acetic anhydride. Selected compounds were screened for in vitro schistosomicidal activity against Schistosoma mansoni at three different dosage levels (10, 50 and 100 μg/ mL). Three of these products, 4a-c, showed schistosomicidal activity similar to praziquantel, with 100% worm mortality at 10 μg/mL. These compounds would constitute a new class of potent schistosomicidal agents.

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Mode of Action of Antitrematodal Agents

Cited by 10 publications

References 79 publications

Fascioliasis: sonographic abnormalities of the biliary tract and evolution after treatment with triclabendazole

Fascioliasis: sonographic abnormalities of the biliary tract and evolution after treatment with triclabendazole

The interactions between drugs and the parasite surface

Synthesis and in vitro Evaluation of New Benzothiazole Derivatives as Schistosomicidal Agents

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