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At least 19 recordsLinked to original sources
PubMed1978

Histopathology and histochemistry of the insects treated with chemosterilants VI: brain damage including reduced neurosecretion caused by chemosterilants in Periplaneta americana (L).

The brain is damaged and neurosecretion is reduced in the P. americana treated with chemosterilants thio-tepa and bis (dimethylamino) dithiazolium chloride. The damage includes, separation of neurolemma, vacuolisation and chromatolysis in the nuclei of neurons and extensive damage to fibres. Reduced neurosecretion, vacuolisation in the cytoplasm and karyolysis in the nucleus of neurosecretory cells, are also observed. These changes in the brain are of considerable importance to understand the mode of action of the chemosterilants.

Animals↗
PubMed1972

Chemosterilization of Culex pipiens fatigans Wiedemann by exposure of aquatic stages. 3. Induction of dominant lethal mutations in the F 1 generation by certain aziridines, phosphoramides, and s-triazines.

In insects it is known that the chemosterilant treatment induces dominant lethal mutations which bring about embryonic death. The possibility of delayed expression of the chemosterilant-induced dominant lethals in F(1) progeny of the tropical house mosquito, Culex pipiens fatigans Wiedemann has been investigated. The chemosterilants employed were 8 aziridinyl compounds, 3 phosphoramides, and 4 s-triazines. In general, all the chemosterilants tested were found to cause different degrees of mortality at different life stages of the F(1) progeny. In this respect the aziridinyl compounds were more effective than the phosphoramides and s-triazines. This effect of the chemosterilants may be useful in the sterile-male technique.

Animals↗
PubMed1973

Prospects of chemosterilant and genetic control of rodents.

This paper discusses some requirements of an ideal rodent chemosterilant, analyses the advantages of chemosterilants over other control methods, and compares the potential values of chemosterilants that affect females, males, and both sexes. Examples are given of specific situations where chemosterilants will be valuable in rodent control, together with suggested methods of applying them. The theory and practicability of using genetics in rodent control are also discussed. Neither the chemosterilant nor the genetic method is expected to become a panacea, but their eventual application will be a significant advance in rodent-control technology. Since both approaches are based on sound biological principles and are relatively safe, they should be helpful in regulating rodent populations in the future.

Animals↗
PubMed1976

Control and management of insect populations by chemosterilants.

Chemosterilants, i.e., chemical compounds that interfere with the reproduction potential of sexually reproducing organisms, can be used in three new approaches to insect control. In the sterile-insect release technique, the principal problem is to develop compounds and methods for their application that would not result in introducing harmful residues into the environment. Because of the unusual and often unique circumstances connected with releasing large numbers of sterilized insects, the residue problem and its cost-benefit aspects must be examined individually for each intended control or eradication program. In the direct application technique, chemosterilants must meet the same efficiency and safety standards required from approved insecticides. Combined insecticidal and sterilizing activity is characteristic for some compounds now being investigated. In the genetic technique, chemosterilants may be used for inducing heritable changes in the insect's genome under laboratory conditions, and such procedures would not present any residue problems. Only the first two chemosterilant techniques are approaching practical application, and their safety aspects require detailed evaluation and assessment.

Chemosterilants↗
PubMed2002

Dose-dependent response to an intratesticular injection of calcium chloride for induction of chemosterilization in adult albino rats.

This study concerned the minimum and optimum effective doses of calcium chloride needed for induction of chemosterilization in male albino rats, 30 days after a single intratesticular injection of calcium chloride (CaCl2.2H2O) solution at 2.5, 5, 10 or 20 mg per 100 g body weight per testis. There was a significant diminution in the relative wet weight of the sex organs (p<0.01), epididymal sperm count (p<0.001), plasma concentration of testosterone (p<0.01), testicular activities of delta5,3beta-hydroxy steroid dehydrogenase (delta5,3beta-HSD), 17beta-hydroxy steroid dehydrogenase (17beta-HSD) (p<0.01), glutathione S-transferase (GST) (p<0.01), superoxide dismutase (SOD) (p<0.01), and peroxidase (p<0.01), significant elevations in testicular content of malondialdehyde (MDA) and conjugated dienes (p<0.01), along with derangement of seminiferous tubular architecture and degeneration of the Leydig cells in the testis and elevations in the concentrations in the plasma of LH and FSH (p<0.01), commencing at a dose of 5 mg, with the greatest effects at a dose of 20 mg. No significant alterations in these factors occurred at the dose of 2.5 mg in comparison to the control that received only the vehicle. There was no significant alteration in the plasma concentrations of prolactin (p>0.05), corticosterone (p>0.05) or fasting blood glucose or in the rectal temperature (p>0.05) at any of the doses relative to the control group, suggesting that this chemosterilizing procedure did not exert any chronic stress on the experimental animals. From these observations, it may be suggested that 5 mg should be considered as the minimum dose, and 10 mg or 20 mg as the optimum dose, whereas 2.5 mg was ineffective for induction of chemosterilization. There would seem to be little point in using more than 20 mg of calcium chloride for this purpose. Intratesticular injection of calcium chloride at an effective dose may be considered as an alternative to surgical castration.

3-Hydroxysteroid Dehydrogenases↗
PubMed1971

Chemosterilant action of anthramycin: a proposed mechanism.

The activity of anthramycin and structurally related analogs as chemosterilants of the housefly, Musca domestica L., correlates closely with the action of these compounds as inhibitors of Escherichia coli RNA polymerase. Since inhibition of RNA polymerase by anthramycin reflects binding of this antibiotic to the DNA primer required for enzyme activity, we propose that the interaction of anthramycin with DNA may also account for its action as a chemosterilant.

Animals↗
PubMed1993

Use of an oestrogen, androgen or gestagen as a potential chemosterilant for control of rat and mouse populations.

Three synthetic steroids were evaluated as potential chemosterilants for rodent control. Ethinyl oestradiol, methyl testosterone or Org 5933, a synthetic gestagen, were incorporated into paraffin blocks containing cereal grains and offered to laboratory rats and mice in addition to their standard laboratory diet. Ethinyl oestradiol (50 mg kg-1 paraffin block) was highly unpalatable to female rats, and the amount of steroid ingested was not sufficient to interfere with their oestrous cycles or inhibit ovulation. Methyl testosterone (5000 mg kg-1 paraffin block), although not as palatable as untreated blocks, was effective in inducing almost immediate infertility in female rats and mice at an ingested dose of about 35 micrograms g-1 body weight day-1. This infertility persisted throughout the duration of treatment, and lasted for several weeks after the cessation of treatment. Male rats became infertile after 3 months of treatment owing to suppression of spermatogenesis. Female rats developed a specific aversion to methyl testosterone when they were pregnant or lactating; it was therefore not possible to masculinize the brains of their female offspring. In mice, the androgen treatment induced high levels of aggression in the females so that they fought with males and with one another. One female died of her wounds. Org 5933 (4 mg kg-1 paraffin block) was highly palatable to female rats and mice, and at doses of about 420 ng g-1 body weight day-1 was effective in inhibiting ovulation in rats within 3 to 4 days after the start of treatment. This infertility persisted throughout the duration of treatment, and the animals conceived within 5 days of cessation of treatment. A dose of about 930 ng g-1 body weight day-1 was not completely effective in inhibiting ovulation in mice, but females that became pregnant during treatment gave birth to dead young. When the gestagen was given to female rats and mice in the last few days of pregnancy, the duration of gestation was significantly prolonged, and most young were born dead; some of the females also died in labour. The gestagen did not appear to inhibit lactogenesis, since the few animals that gave birth to live young reared them normally for the first 5 days of life. These results show that either methyl testosterone or Org 5933 in paraffin blocks could perhaps be used as a chemosterilant for the control of rat and mouse populations.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1964

THE TOXICOLOGY OF CHEMOSTERILANTS.

Sterilization of males can in certain circumstances be more efficient than killing as a method for control of insects and perhaps other pests. A number of chemicals (chemosterilants) show promise of producing sexual sterility in insects without some of the practical limitations of radiation. The most important compounds are alkylating agents. These have little immediate pharmacological action, but are notable for their selective action against haematopoietic and some other proliferating tissues. A number of alkylating agents have been shown to be mutagens in insects, bacteria, fungi, and higher plants; carcinogens in mammals; and teratogens in insects, birds, and mammals. Some produce sexual sterility, possibly in mammals as well as in insects, at doses too low to produce the other effects. Some have an established reputation as drugs for palliative treatment of leukaemia and other neoplasms.The development of insect sterilization as a vector control technique has been handicapped in part by lack of scientific information on the acute and long-term hazards that might be associated with the use of chemosterilants. In this paper the author brings together the available knowledge on the toxicology of the alkylating agents.

Alkylating Agents↗
PubMed1973

Dispersal and survival in the field of chemosterilized, irradiated, and cytoplasmically incompatible male Culex pipiens fatigans.

Comparative field studies were made on the dispersal and survival of chemosterilized, irradiated, and cytoplasmically incompatible (D3 strain) male Culex pipiens fatigans. There was no significant difference in dispersal patterns and daily survival rates between laboratory colony males and wild males, and between chemosterilized or irradiated males and untreated males. Although there was no difference in dispersal between adults of the D3 strain and the laboratory colony of the Delhi strain, the former had a lower daily survival rate.

Animals↗
PubMed1969

Chemosterilization of Culex pipiens fatigans Wiedemann by exposure of aquatic stages. I. Sterilization potential of certain aziridinyl compounds.

The sterile-male technique has been considered to be a promising tool for the control of mosquito populations. Many chemosterilants are known to sterilize insects effectively in the same way as ionizing radiations. The sterilizing activity of 8 alkylating aziridinyl compounds has been assessed on the tropical house-mosquito, Culex pipiens fatigans Wiedemann. The chemosterilants employed for larval and pupal treatments were apholate, metepa, tepa and 5 diaziridinyl alkoxyphosphine oxides. In general, metepa was least toxic to the various life stages of C. p. fatigans during the treatment. Apholate was toxic only in pupal treatments while tepa was less toxic in pupal treatments and more toxic in larval treatments. Diaziridinyl compounds were moderately toxic in both larval and pupal treatments. The tepa and apholate treatments caused certain structural and moulting abnormalities in pupae and adults and also induced abnormalities in eggs and larvae.Among the polyaziridinyl compounds, non-toxic doses of apholate could produce about 100% sterility with larval treatment. Tepa was inferior to apholate, and metepa was least effective in larval treatment. Among the diaziridinyl compounds, the methyl ester was most promising. For pupal treatment, tepa was more effective than apholate and metepa at non-toxic doses, inducing almost complete sterility. The propyl and isopropyl esters of the diaziridinyl compounds also induced very high sterility in pupal treatments.

Animals↗
PubMed1982

[Acaricidal, chemosterilant and insecticidal activity of triazine derivatives].

A large number of 1-aryl-3,3-dialkyl triazenes and 1,2-diphenyl triazenes variously substituted in the 3 position with OH and alkyl groups were prepared and studied for acaricide activity against Panonychus ulmi and chemosterilizing and insecticidal activity against Musca domestica. The results highlighted the marked chemosterilizing activity of 1-(2-methoxyphenyl)-3,3-di-n-propyltriazene and the interesting acaricidal activity of 1-(4-benzoylphenyl)-3,3-dimethyltriazene. The examination of such a large number of compounds for insecticidal activity allowed interesting conclusions to be drawn regarding structure/activity relationships.

Acari↗
PubMed1975

Analysis of insect chemosterilants.

Background information concerning the concept of insect chemosterilization and analytical methods for determining trace levels of 19 P- and/or S- containing chemicals of current interest are presented. GC retention times of the compounds on 6 different columns and their p-values in 11 solvent systems are tabulated. The utility of the flame photometric detector for determining subnanogram levels of the sterilants in biological substrates is illustrated.

Animals↗