Effect of anthelmintics

Saz, H.J. (1971) Anaerobic phosphorylation in Ascaris mitochondria and the effects of anthelmintics. Comparative Biochemistry and Physiology 39B, 627-637. 

Pampori, N. A., Singh, G. Srivastava, V. M. L. (1984a). Cotugnia digonopora carbohydrate metabolism and effect of anthelmintics on immature worms. Journal of Helminthology, 58 39-47. 

Pook J F, Power M L, Sangster N C et al 2002 Evaluation of tests for anthelmintic resistance in cyathostomes. Veterinary Parasitology 106 331-343 Prichard R K, Hennessy D R, Steel J W 1978 Prolonged administration a new concept for increasing the spectrum of effectiveness of anthelmintics. Veterinary Parasitoiogy 4 309-315... 

A. El-Makawy, H. A. Radwan, 1. S. Ghaly and A. A. El-Raouf, Geno-toxical, teratological and biochemical effects of anthelmintic drug oxfendazole Maximum Residue Limit (MRL) in male and female mice, Nutr. Reprod. Dev., 2006, 46, 139-156. 

In 1971, levamisole, an anthelmintic compound widely used in catde and swine, was shown to improve the effects of an experimental Brucella abortus vaccine in mice. Since that time, the veterinarians and physicians have explored the effects of levamisole in such diverse areas as arthritis, lupus erythematosis, cancer therapy, respiratory diseases, Newcastle disease, foot-and-mouth disease, mastitis, and vaccine potentiation. Although the exact mechanism of action has as yet not been deterrnined there is substantial evidence that, under defined circumstances, levamisole can augment the animal s natural immune response (9). New immunostimulants include Staph Ijysate acemannon, NLAB-31. 

Over the last several years, substantial progress in the discovery and development of anthelmintic dmgs has been made. Effective agents are available for most human gastrointestinal infections (Table 1) however, dmgs that are effective in treating the extraintestinal complications of many helminthic infections are still needed. 

Figure 21.11A illustrates representative vesicle-attached recordings from a sensitive isolate (SENS), a pyrantel-resistant isolate (PYRR) and a levamisole-resistant isolate (LEVR) produced by 30 pM levamisole. There are differences in mean P-open values of receptors between sensitive and resistant isolates that would produce, on average, a reduction in the effect of the anthelmintic. However, one of the puzzling, but very consistent, observations is that there is a big range in the P-open values observed in different patches under the same experimental conditions in the same isolate (Fig. 21.1 IB). For example, the P-open values of the sensitive isolate were observed to vary between 0.090 and 0.003 at -50 mV with 30 pM levamisole, a 30-fold difference between the biggest and the smallest P-open...

Our working hypothesis is that subunit stoichiometry or changes in the structure of individual receptor subunits give rise to the different conductance subtypes and that phosphorylation by the different kinase enzymes has major effects on the P-open values of the receptor. Should the hypothesis hold, then alterations in the phosphorylation state of the receptor by the different kinase enzymes may (as stated earlier) be important in the development of anthelmintic resistance. 

This dual activity against both nematode and arthropod parasites of animals was an unexpected bonus from a screen for anthelmintic agents. The reason for this broad activity lies in their mode of action. They act by interfering with y-aminobutyric acid (GABA) mediated neurotransmission. When treated with avermectin, the nematode Ascaris suum becomes paralyzed although it retains normal muscle tone (17). Picrotoxin, an antagonist of GABA, can reverse the effect of avermectin on neurotransmission vitro. 

Del Estal J.L., A.I. Alvarez, C. Villaverde, and J.G. Prieto (1993). Comparative effects of anionic, natural bile acid surfactants and mixed micelles on the intestinal absorption of the anthelmintic albendazole. International Journal of Pharmaceutics 91 105-109. 

Jensen J., P.H. Krogh, and L.E. Sverdmp (2003). Effects of the antimicrobial agents tiamuhn, olanquindox and metronidazole and the anthelmintic ivermectin on the soil invertebrate species Folsomia fimetaria (Collembola) and Enchytraeus crypticus (Ench3draeidae). Chemosphere 50 437-443. 

To investigate the effect of changes at the C26 position of MFA on anthelmintic activity, several of C26-dialkyl and spiroalkyl analogs were prepared [47]. The analogs were synthesized in four steps starting with cathecol 66 [Fig. (19)], which was prepared from MFA in 80% yield by stirring in formic acid for 16 h. 

To investigate the effect on anthelmintic activity by changing the substituent pattern at C24/C25, we synthesized a number of analogs [Fig. (22)] [50],... 

Stitt, A.W and Fairweather, I. (1992) Spermatogenesis in Fasciola hepatica an ultrastructrual comparison of the effects of the anthelmintic, triclabendazole ( Fasinex ) and the microtubule inhibitor, tubulozole. Invertebrate Reproduction and Development 22, 139-150. 

Chubb, J.M., Bennett, J.L., Akera, T. and Brody, T.M. (1978) Effects of praziquantel, a new anthelmintic, on electromechanical properties of isolated rat atria. Journal of Pharmacology and Experimental Therapeutics 207, 284-293. 

Some of the common anthelmintics used to kill the basic types of worms in humans are listed in Table 35-5. These agents are often very effective a single oral dose is usually sufficient to selectively destroy the parasite. Brief descriptions of the basic pharmacologic effects and possible adverse effects of the primary anthelmintic agents are presented below. Several authors have also extensively reviewed the pharmacologic treatment of helminthic infections.36,41,52,58,66... 

Mebendazole is a synthetic benzimidazole (compare with albendazole) that has a wide spectrum of anthelmintic activity and a low incidence of adverse effects. 

Southernwood is mainly employed in menstrual obstruction, frequently in combination with Mugwort and Pennyroyal. Wineglass doses are taken of the infusion of 1 ounce of the herb to 1 pint of boiling water. The powdered herb is sometimes given in teaspoonful or smaller doses to children suffering from worms, but such agents as Tansy and Wormwood are perhaps more effective as anthelmintics. 

Stoltzfus RJ, Kvalsvig JD, Chwaya HM, Montresor A, Albonico M, Tielsch JM, Savioli L, Pollitt E (2001) Effects of iron supplementation and anthelmintic treatment on motor and language development of preschool children in Zanzibar Double blind, placebo controlled study. BMJ, 323(7326) 1389-1393. 

---