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Cyclophosphamide as a potential chemosterilant for harmful snails.

Cyclophosphamide induced changes in the ovotestis of the snail Lymnaea acuminata, the vector of the giant liverflukes Fasciola hepatica and Fasciola gigantica were studied in order to explore potential of the drug as a chemosterilant for snails. The drug caused a dose dependent reduction in the levels of DNA, RNA and proteins and the activity of the enzyme alkaline phosphatase. It increased the activity of acid phosphatase and the levels of total free amino acids in the ovotestis. While the animals showed nearly total recovery in RNA and DNA levels 7 days after termination of drug treatment, changes produced in protein, amino acid levels and phosphatase activity did not show any recovery. It appears that cyclophosphamide, while affecting its primary targets i.e. DNA and RNA, irreversibly inhibits protein synthesis through other cellular enzymes as well.

Acid Phosphatase↗

INSECT CHEMOSTERILANTS WITH LOW TOXICITY FOR MAMMALS.

Hexamethylphosphoramide and hexamethylmelamine are effective as male house fly chemosterilants. Both compounds are structurally similar to the two highly active sterilants tepa and tretamine, but they differ from the aziridinyl compounds in their low toxicity for mammals and in their lack of alkylating properties. This discovery of nonalkylating male sterilants of low toxicity should substantially increase the scope and practicality of the sterilemale control method.

Amides↗

Pigeon control by chemosterilization: population model from laboratory results.

Reproductivity of pigeons is inhibited with mestranol incorporated in a synthetic grit; continual erosion releases daily doses. Young squabs may be permanently sterilized when fed crop milk by treated birds. A theoretical model of pigeon population dynamics using laboratory-obtained data shows the advantages of chemosterilization over killing as a means of pigeon control.

Animals↗

Duration of sterility induced in males of the tropical house mosquito, Culex pipiens fatigans Wiedemann, by the chemosterilants apholate and tepa.

Various alkylating and non-alkylating agents are known to induce sterility in Culex pipiens fatigans, but the duration of the sterilizing effect they produce had not so far been studied for this species. The authors therefore investigated the duration of sterility induced by the alkylating chemosterilants apholate and tepa in C. p. fatigans, second-instar larvae being exposed to 10 ppm apholate or pupae to 3570 ppm tepa. They found that, in experiments in which treated males were mated once only, both apholate and tepa induced sterility lasting at least 48 days. However, in experiments in which males were mated once weekly for 6 weeks apholate-treated males showed a slight recovery from the early sterilizing effect. On the other hand, tepa was found to be very effective in inducing lasting sterility throughout the 6 successive matings. The probable reasons for the recovery from sterility of apholate-treated males and the more lasting sterility of tepa-treated males are discussed.

Alkylating Agents↗

Chemosterilization of Culex pipiens fatigans Wiedemann by exposure of aquatic stages. 2. Sterilization potential of certain phosphoramides and s-triazines.

Many aziridinyl compounds are known to induce high sterility in Culex pipiens fatigans Wiedemann, but as the practical application of these chemosterilants is quite hazardous, compounds such as phosphoramides and s-triazines have been tried against this species. These compounds are relatively less reactive, thermally more stable and less toxic to mammals. The phosphoramides included hempa, N,N,N',N'-tetramethyl-P-piperidino-phosphonic diamide (ENT-51007) and a compound, ENT-60210, whose structure is not known to the authors. The s-triazines employed were hemel, 2,4-diamino-6-morpholino-s-triazine hydrochloride (ENT-51143), 2-amino-4,6-bis (dimethylamino)-s-triazine hydrochloride (ENT-51146), and a compound ENT-60433, whose structure is not known to the authors.The triazines were more toxic than the phosphoramides in both larval and pupal treatments. Among the phosphoramides, hempa and ENT-51007 were quite promising for larval treatment and resulted in 80% and 83% control of reproduction respectively at non-toxic doses. Hempa at a toxic dose induced complete sterility. ENT-60210 was least toxic and least effective. Among the triazines, hexa-substituted hemel was better than tetra-substituted ENT-51146 and cyclic-substituted ENT-51143 in inducing sterility. ENT-51143 was most toxic and least effective. For larval treatment, hempa was better than hemel in inducing sterility while for pupal treatment the latter was better than hempa. Both the compounds produced more sterility in treated females than in treated males. Oviposition was significantly lowered in treated females.

Amides↗

[Cytogenetic activity of the harmful insect chemosterilant, dimatif, on mouse bone marrow cells].

The new insects' chemosterilant, dimatyph, (diethylene-imide amidothiophosphorous acid) induced a significant increase of chromosomal aberrations in the mouse bone marrow cells after a single per os treatment in doses of 100.0, 10.0, 1.0, 0.1 mg/kg. An extremely high mutagenic activity of dimatyph (maximal cytogenetic effect 33.6%, minimal effective dose 1.0 mg/kg) does not permit a widespread use of this substance as a pesticide.

Animals↗

A chemosterilized antigen-extracted autodigested alloimplant for bone banks.

Limited chemical extraction of hydrophobic glycopeptides and subtotal autodigestion of the donor's cells and plasma membranes in undemineralized cortical bone in vitro reduces the putative quantity of haptenic substances absorbed by the recipient. Iodoacetic acid and sodium azide or other sulfhydryl group enzyme inhibitors added to the buffer solutions during in vitro autodigestion and estraction of intracellular alloantigens protects the bone matrix morphogenetic property against enzymatic degradation. The delayed hypersensitivity reaction induced by aseptically collected freeze-dried bone and the destruction of the bone morphogenetic property caused by radiation-sterilization is avoidable by sequential chemodigestion and chemosterilization of bone that preserves the maximum morphogenetic potential while transferring a minimum quantity of alloantigen.

Animals↗

Cytogenetic and other effects of the chemosterilants tepa, metepa, apholate an hempa in insects (a review).

A review of the literature revealed that the chemosterilants tepa (tris(1-aziridinyl)phosphine oxide), metepa (tris(2-methyl-1-aziridinyl) phosphineoxide), apholate (2,2,4,4,6,6-hexakis(1-aziridinyl)-2,2,4,4,6,6-hexahydro-1,3,5,2,4,6-triazatriphosphorine), and hempa (hexamethylmelamine) affected both reproductive and somatic tissues in over 65 species of insects. The effects were cytological, physiological, and genetic and varied from slight to severe. In some cases the deleterious effects may have been species-specific, but in general, they appeared to be dose-dependent. More than 150 publications are cited.

Animals↗

Larvicidal and chemosterilant activity of the acetone fraction of petroleum ether extract from Argemone mexicana L seed.

The acetone fraction of the petroleum ether extract of seeds from Argemone mexicana L. exhibited larvicidal and growth inhibiting activity against the second instar larvae of Aedes aegypti (Linn). This activity occurred at higher concentrations (200, 100, 50 and 25 ppm). Chemosterilant activity, including reduction in blood meal utilization (27.70%), reduction in fecundity (19.00%), formation of larval-pupal intermediates, formation of pupal-adult intermediates, adult mortality and sterility of first generation eggs (100%), occurred at low concentration (10 ppm).

Acetone↗

Chemosterilant (apholate)-induced ultrastructural changes during oogenesis in Aedes aegypti.

The effect of chemosterilant, apholate, on-oogenesis has been studied in Aedes aegypti. Treatment of larvae to 20 ppm of the chemical induced ultrastural changes in the presumptive and primary follicles of the adult ovary. These changes comprised condensation of chromatin, disruption of nuclear envelope and extensive degeneration as evidenced by numerous myelin figures and residual bodies. In some primary follicles, where cellular degeneration was restricted to epithelial cells, no arrest in development was observed. However, in comparison with controls, these follicles also were retarded. Larval treatment with 30 ppm apholate completely supressed ovariolar development. High incidence of autophagy was observed in tissues at both dose levels.

Aedes↗

Biochemical and electrophoretical studies of the effect of some chemosterilants on theenzymes of aedes aegypti (L.) larvae.

In vivo effect of standard and prospective chemosterilants on some enzymes is reported. Colorimetric and histochemical findings indicate that alkaline phosphatase is inhibited by shikonin, hempa, tepa and shikonin angelate. Cholinesterase is inhibited by all the compounds while diphenol oxidase is not inhibited. These findings have been discussed in the light of the earlier observations.

Journal Article↗

Chemosterilization of Dermacentor variabilis Say (Acari: Ixodidae). I. Effects of metepa on the cytology and fertility of males treated as unfed adults.

The effects of metepa on the cytology and fertility of male Dermacentor variabilis treated as unfed adults are determined. Evidence of cellular damage is found in testicular areas where actively dividing cells and some enlarging spermatocytes are found. The amount of cellular damage correlates positively to the concentration of the chemosterilant and results in decreases numbers of spermatids. In crosses of treated males to untreated females, resulting egg masses hatch normally; however, the percentage of females producing egg masses that hatch is reduced.

Animals↗

Larvicidal and chemosterilant activity of Annona squamosa alkaloids against Anopheles stephensi.

Alkaloids isolated from Annona squamosa have shown larvicidal growth-regulating and chemosterilant activities against Anopheles stephensi at concentrations of 50 to 200 ppm. Adults exposed as larvae to different treatments showed reduced fecundity and fertility in females. Mortality in the larvae, pupae and adults produced about a 52-92% decrease in the laboratory experiment. The total developmental period was slightly reduced from the control. Treatment with the alkaloids had a significant effect on the mortality, emergence and reproductive physiology of An. stephensi.

Alkaloids↗

Efficacy of lufenuron as chemosterilant against Ceratitis capitata in field trials.

Two field trials in citrus orchards in Turis (Valencia, Spain) and Denia (Alicante, Spain) were performed in order to test the sterilant effect of the insect growth regulator lufenuron against wild medfly Ceratitis capitata (Wiedemann) populations. Two application methods for lufenuron were tested: spraying, in spots, an emulsion of lufenuron in a protein bait, and hanging delta traps that contained a proteinaceous gel with lufenuron (solid bait). The sterilant effect was measured as medfly population reduction, reduction of fruit damage in treated fields, and the number of eggs hatching in punctured fruits. In order to assess the efficacy of lufenuron treatments, we recorded results obtained from two different zones in both trial fields: an outer zone, close to untreated fields, and an inner zone, in the centre of lufenuron treated fields. We observed a minimum sterilant effect in the outer zone and a maximum sterilant effect in the inner one. The maximum sterilant effect was in the inner zone, where a reduction of medfly population of 80.4% in the sprayed field and a reduction of 77.6% in the solid bait field was observed. In addition, the greater the distance from the untreated zones of the treated orchard (inwards), the lower the fruit damage and medfly population level. In this inner zone, fruit punctured by medfly developed significantly fewer larvae (38.8%) than punctured fruits from the outer zone (68.6%). In addition, we recorded the decline in the activity of the lufenuron treatments with time. Lufenuron activity persisted in field for at least 2 weeks with spray applications, and for 3 months with bait gels.

Animals↗