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PubMed1986

Management of acute childhood poisonings caused by selected insecticides and herbicides.

Most childhood exposures to insecticides and herbicides do not result in poisonings. Decontamination and observation are usually adequate treatments. The most frequent exposures involve carbamate and organophosphate insecticides. These compounds inhibit acetylcholinesterase, resulting in cholinergic signs that are reversible with atropine administration. Recent reports from poison control centers indicate that organophosphates have been associated with most of the serious childhood poisonings. Pralidoxime, a cholinesterase reactivator, must be administered along with atropine to patients with serious organophosphate poisoning, to reverse nicotinic receptor effects--in particular, respiratory paralysis. Although carbamates and organophosphates may cause clinically indistinguishable physical signs, pralidoxime therapy may be contraindicated for carbamate intoxications. In the event of a serious poisoning caused by a combination of organophosphate and carbamate insecticides, or by an unknown cholinergic agent, pralidoxime should not be withheld. Many organochlorine insecticides are restricted or are no longer available in the United States. CNS excitation and seizures, manifestations of organochlorine intoxication, can occur following ingestion or inappropriate application of the 1 per cent topical formulation of lindane used to treat scabies and lice. Treatment of such intoxication consists of decontamination measures and anticonvulsant administration. Pyrethrins are generally nontoxic in doses commonly ingested. Individuals with an allergic history may be at greatest risk for the most common adverse effects, contact dermatitis and hypersensitivity reactions. Of all insecticides or herbicides, paraquat is the most toxic. Any exposure to paraquat must be evaluated, even if several days have passed since the herbicide was ingested. Signs of pulmonary status deterioration usually portend a grave prognosis in paraquat poisoning. Despite in vitro toxicity similar to paraquat, diquat does not cause lung effects in human poisonings, and reported deaths have been from other causes. Poisoned patients who receive appropriate and timely treatment are virtually assured of complete recovery from most insecticide and herbicide poisonings. Deaths and long-term sequelae most often result from respiratory complications, which may occur as complications of the intoxication or from other constituents in the insecticide or herbicide formulation. Good supportive care with meticulous attention to, and anticipation of, respiratory complications is absolutely essential to prevent long-term sequelae or death from hypoxia.(ABSTRACT TRUNCATED AT 400 WORDS)

Absorption↗

PubMed2002

Analysis and implications of aircraft disinsectants.

Aircraft disinsection is required by various countries. In-flight spraying with a 2% phenothrin aerosol exposes passengers and crew directly. Residual spaying uses a permethrin emulsions in the absence of passengers and crew and results in dermal and oral exposures. Exposed passengers and crew often complain of, skin rashes, respiratory problems, tingling and numbness in fingertips and lips and burning eyes. A number of formulations were analyzed for their constituents using GLC-Mass. spec. Volatile organic compounds (VOCs) were found in all aerosol preparations including, ethyl benzene and xylene isomers along with phenothrin. Residual sprays contained, cis-, and trans-, permethrins, palmidrol, and occasionally naphthalene. Headspace analysis found methylene chloride and hexene derivatives but not the active ingredients. The known synergistic effects between organophosphates and pyrethrins, based on carboxyesterases inhibition, can be expected in the presence of Tricresylphosphates (TCPs), constituents found in jet engine oils and in some hydraulic fluids. During oil seal failure, the presence of TCP in the ventilation air could explain the increased sensitivity of some crew members and passengers to disinsectants.

Aerosols↗

PubMed1996

Cytogenetic effects of piperonyl butoxide and safrole in CHO-K1 cells.

Recently, hepatocarcinogenicity in rats and mice was reported with regard to the methylenedioxyphenyl compound, piperonyl butoxide (PB), which is used as a synergist for pyrethrins and related insecticides. Induction of sister-chromatid exchanges (SCEs) and chromosomal aberrations (CAs) due to PB were investigated using CHO-K1 cells with or without rat liver S9 fraction (S9); at the same time, the effects of safrole (SF), a methylenedioxyphenyl compound and a weak hepatocarcinogen, were also examined. PB (0.25 and 0.3 mM) and SF (0.8 mM) caused a slight but significant increase in SCEs followed by a cell-cycle delay in the 3-h treatment without S9. In the presence of S9 (4.5%), the cytotoxicity of PB or SF was weakened greatly or slightly, the top dose capable of cell division was raised to 0.6 mM (2-fold) or 1 mM, respectively. PB with S9 induced SCE at doses of 0.4 and 0.5 mM, and caused endoreduplications (ERDs, 7%) at a dose of 0.6 mM, while SF caused a dose-related significant increase in SCE at all doses used (0.4-1 mM) with S9. Genotoxicity of the metabolites of PB or SF was cleared by changing the dose of S9 (1.5-9%) while holding the dose of each chemical constant. In the case of SF (0.6 mM), induction of SCE, ERD and cell-cycle delay intensified almost in a dose-effect relationship, and CAs and a high level of ERD (14%) were caused by a 9% dose of S9. The concentration of unchanged SF in the incubated medium was certainly in inverse proportion to the dose of S9. This strongly suggests that the metabolites of SF are genotoxic. In the case of PB (0.3 mM), no positive responses were produced in the cultures, even with a high level of S9, though the amount of unchanged PB left in the incubated medium was very slight. This indicates that the metabolites of PB may not be genotoxic. In conclusion, PB and SF are possible to somewhat induce SCE at high dose(s) in the absence of S9, and the genotoxic effects of SF are more intensified in the presence of S9 than in its absence, while PB is probably no genotoxic in the presence of sufficient metabolic activation.

Animals↗

PubMed1981

Treatment of scabies and pediculosis with lindane preparations: an evaluation.

Risks and benefits involved in the use of lindane preparations for the treatment of scabies and head louse infestations are evaluated. Although lindane per si is moderately toxic, capable of inducing neurotoxic and hemotoxic effects, there is little evidence that the preparations used in the treatment of scabies and pediculosis give rise to toxic symptoms when applied according to directions. Current evidence does not support the view that lindane is intrinsically carcinogenic, although very high doses have induced hepatomas in mice. It is concluded that the benefits obtained in the use of lindane as a scabicide and pediculicide outweigh risks involved in its use for these purposes. Comparison with other preparations available for the control of scabies and pediculosis indicate that lindane is probably the most effective scabicide, although it also shows the greatest toxic potential. Malathion and pyrethrin preparations seem equally effective against head lice. Suggestions for even safer use of lindane are discussed.

Animals↗

PubMed2000

Efficacy and safety of selamectin against fleas on dogs and cats presented as veterinary patients in Europe.

Two controlled and masked multi-centre studies were conducted to examine the efficacy of a novel topical avermectin, selamectin, against natural flea infestations on 418 dogs and 345 cats. Veterinary patients with viable flea infestations were enrolled in the studies, which were conducted in United Kingdom, France, Germany, and Italy. Animals were allocated randomly in a 2:1 ratio to one of two treatments: either selamectin alone at a minimum dosage of 6mgkg(-1) or fenthion at recommended dose rates. Concurrent use of an environmental spray (containing methoprene and either pyrethrins or permethrin) was permitted only for fenthion-treated animals. In-contact cats and dogs (animals living in the same home) received the same treatment as the first animal enrolled from the household, if recommended by the veterinarian. Study day 0 was defined as the day of first treatment. Animals were treated on days 0, 30, and 60, and flea comb counts and clinical evaluations were conducted on days 0, 14, 30, 60, and 90. Analysis of variance of ln(flea count+1) showed that values were significantly lower for selamectin alone compared with fenthion (with or without the concurrent use of an environmental spray) in dogs on days 30, 60, and 90 (P<0.05) and in cats on days 14, 30, 60, and 90 (P<0.01). For selamectin, the reductions in geometric mean flea counts on days 14, 30, 60, and 90, compared with day 0, were 92.5, 90.7, 98.1, and 99.1%, respectively, for dogs and 92.8, 92.7, 97.7, and 98.4%, respectively, for cats. Selamectin was shown to be safe and highly effective in the control of naturally acquired flea infestations on dogs and cats presented as veterinary patients in Europe.

Animals↗

PubMed2002

Urban wastewater treatment by a nutrient film technique system with a valuable commercial plant species (Chrysanthemum cinerariaefolium Trev.).

Urban wastewater causes rapid eutrophication of natural waters and requires treatment before discharge. This is expensive and produces huge quantities of sludge. In the European Community, it will no longer be lawful to dispose of this sludge as landfill after 2005 (European Directive 91/271/CEE of May 21, 1991). Wastewater treatment by the Chrysanthemum cinerariaefolium plants in horizontal flow was investigated using the nutrient film technique (NFT), a widely used hydroponic system in the commercial greenhouse industry. After a 48 h plant treatment, the purification efficiency was 95%, 91%, and 99% with respect to suspended solids (SS), biochemical oxygen demand (BOD5), and chemical oxygen demand (COD), and the elimination of nutrients (total nitrogen and total phosphorus) varied between 40% and 80%. SS and thus indirectly BOD5 and COD were removed by filtration and adsorption; the solids trapped in the root systems were then decomposed and mineralized. The system with 25 plants purified 30 L of wastewater in 48 h. One-hundred people communities wastewater could be treated with a 6 m2 area of production. Pyrethrin contents and chlorophyll a fluorescence of plants grown on raw urban waters were not significantly different from those grown on a standard nutrient solution.

Adsorption↗

PubMed1998

Comparative efficacy of pyrethrum marc with albendazole against sheep gastrointestinal nematodes.

The efficacies of pyrethrum marc and of albendazole against experimental sheep gastrointestinal nematode infection were compared. Sheep was infected orally with 10,000 larvae (Haemonchus spp. (60.1%), Oesophagostomum spp. (13.9%), Trichostrongylus spp. (13.2%), Cooperia spp. (8.3%), Nematodirus spp. (3.5%), Strongyloides spp. (0.8%) and Ostertagia spp. (0.2%). Faecal egg count reduction in albendazole-treated sheep was 100% by day 4 following treatment, compared to 37.03%, 31.3%, 38.9% and 51.8% on days 4, 6, 8 and 10 in pyrethrum mare-treated sheep. These reductions were statistically significant on days 8 and 10 post-treatment (p < 0.05). The potential for using pyrethrins for helminth treatment is discussed.

Albendazole↗

PubMedDate not supplied

Pesticide storage and use patterns in Minnesota households with children.

As part of the National Human Exposure Assessment Survey (NHEXAS), residential pesticide storage and use patterns were evaluated in a population-based sample of Minnesota households with children aged 3-13. In-home interviews and inventories were conducted to identify pesticide products stored and used in and around 308 households. This statistically based sample represents more than 49,000 urban and rural households in the census tracts sampled. More than 850 unique products were identified using Environmental Protection Agency (EPA) registration numbers. Pesticide products were found in 97% and reported used in 88% of study households. Population-weighted mean values for pesticide storage and use were 6.0 and 3.1 products per household, respectively. The most common active ingredients found were diethyl toluamide (DEET) and related compounds, piperonyl butoxide, pyrethrins, dimethylamine 2-[2-methyl-4-chlorophenoxyl propionate (MCPA) and chlorpyrifos. Household socio-demographic characteristics explained little of the variability in pesticide storage and use patterns, and there were no significant differences in residential storage and use patterns between households located in urban versus non-urban census tracts. Although the prevalence of households with pesticide products was similar to recent national surveys, observed storage and use rates were almost twice those obtained in recent national studies, reflecting improved inventory techniques used by this study and/or increased rates of pesticide presence and use in study households.

Adolescent↗

PubMed1997

Head louse infestations: epidemiologic survey and treatment evaluation in Argentinian schoolchildren.

BACKGROUND: Our aim was to demonstrate that the treatment of individual cases is effective, but not sufficient, to control endemic Pediculus capitis, and that eradication of the epidemiologic school focus may lower significantly the prevalence of infestation. Statistical data on the degree of infestation relating to socio-economic and cultural variables were also updated. Therapeutic effects and educational impact were evaluated. METHODS: An educational and motivational program was designed for pupils, parents, and teachers: 326 children and 15 adults were subjected to clinical and parasitologic evaluation. The recorded parameters included the age, sex, hair style and length, presence of other dermatologic diseases, degree of infestation, clinical remission, parasitologic remission, dwelling type and features, need to share a bed with co-dwellers, availability of home tap water supply, level of family income, and periodic medical controls. The entire population received treatment with neutral shampoo and rinsing cream containing 1% permethrin. Exclusion criteria were the presence of acute scalp inflammation and a history of pyrethrin and/or pyrethroid sensitivity. Statistical analysis was performed as required on data expressed as frequencies, percentages, means, and standard deviations by chi-square and Fisher exact tests. RESULTS: The overall infestation prevalence rate was 81.5%, the highest values corresponding to children from 6 to 11 years of age, with a slight predominance in males (55.4% vs. 44.6%). A significantly greater rate of clinical remission was observed in subjects enjoying home tap water supplies (p < 0.01). CONCLUSIONS: The model of research plus action adopted allows the following conclusions to be drawn: (i) individual and isolated treatments for pediculosis are useful, but will not by themselves allow for the epidemiologic control of this parasitosis; (ii) massive, complete, and simultaneous treatments lead to a significant decrease in infestation prevalence; (iii) educational measures tending to foster collective awareness enable greater epidemiologic surveillance to be achieved; (iv) careful inspection of the entire scalp is essential with the use of a powerful light source and lenses with high magnification, as the parasite has no predilection for any given area; (iv) socio-economic and cultural conditions are not relevant for infestation, although a good home tap water supply is essential for treatment.

Adolescent↗

PubMed2001

Chrysanthemyl diphosphate synthase: isolation of the gene and characterization of the recombinant non-head-to-tail monoterpene synthase from Chrysanthemum cinerariaefolium.

Chrysanthemyl diphosphate synthase (CPPase) catalyzes the condensation of two molecules of dimethylallyl diphosphate to produce chrysanthemyl diphosphate (CPP), a monoterpene with a non-head-to-tail or irregular c1'-2-3 linkage between isoprenoid units. Irregular monoterpenes are common in Chrysanthemum cinerariaefolium and related members of the Asteraceae family. In C. cinerariaefolium, CPP is an intermediate in the biosynthesis of the pyrethrin ester insecticides. CPPase was purified from immature chrysanthemum flowers, and the N terminus of the protein was sequenced. A C. cinerariaefolium lambda cDNA library was screened by using degenerate oligonucleotide probes based on the amino acid sequence to identify a CPPase clone that encoded a 45-kDa preprotein. The first 50 aa of the ORF constitute a putative plastidial targeting sequence. Recombinant CPPase bearing an N-terminal polyhistidine affinity tag in place of the targeting sequence was purified to homogeneity from an overproducing Escherichia coli strain by Ni(2+) chromatography. Incubation of recombinant CPPase with dimethylallyl diphosphate produced CPP. The diphosphate ester was hydrolyzed by alkaline phosphatase, and the resulting monoterpene alcohol was analyzed by GC/MS to confirm its structure. The amino acid sequence of CPPase aligns closely with that of the chain elongation prenyltransferase farnesyl diphosphate synthase rather than squalene synthase or phytoene synthase, which catalyze c1'-2-3 cyclopropanation reactions similar to the CPPase reaction.

Amino Acid Sequence↗

PubMed2001

Use of laminar cup liners for the preparation of fatty samples for pesticide analysis.

Residue analyses have been developed for hundreds of pesticides and their metabolites in foods. Normally, the fat is extracted with a non-polar solvent, followed by a re-extraction of the analytes into a polar solvent, removal of the remaining fat by several clean-up steps and finally determination by gas chromatography (GC). Over the last 3 years, experience has been gained in the use of laminar cup liners for GC injectors. The geometry of the laminar cup liner allows the injection of sample extracts with a residual fat content of tip to 5%. The cup prevents fatty compounds entering the capillary GC column. Using this approach, several residue methods can be simplified without losing precision or recovery. The preparation of the samples, such as cows milk, human milk, avocado and cosmetics can be reduced to one solvent extraction step with petroleum ether and one single cleanup step with an Extrelut column. No further clean up with Florisil or GPC is then necessary. The proposed method using a laminar cup and GC/ECD has been tested for the analysis of organochlorine and organophosphorous pesticides, PCBs, nitro-musk fragrances, together with pyrethroids and pyrethrins in the above matrices. Polycyclic musk substitutes were analysed by GC/MS.

Animals↗

PubMed2000

Biotechnological production of plant-based insecticides.

The demand for natural and nonpersistent insecticides is increasing day by day. Plant cell cultures could be an alternative to conventional methods of production of insecticides from field-grown plants. In vitro cultured plant cells produce a wide array of insecticides as a part of their secondary metabolism. Their ability to synthesize key enzymes and the manipulation of these could lead to the enhanced production of many insecticides of industrial importance. The development of a high-yielding hairy root culture system for thiophenes, nicotine, and phytoecdysones is of considerable interest. In this article, the current literature on various factors that influence the growth, production, and secretion of six insecticidal compounds, namely, pyrethrins, azadirachtin, thiophenes, nicotine, rotenoids, and phytoecdysones which have been prospects for the scale-up of cell cultures, genetic engineering to obtain transgenic plants, and metabolically engineered plants for increased production of bio-molecules, has been discussed. Environmental safety clearance and the future prospects of application of biomolecules for plant-derived insecticides are presented.

Biotechnology↗

PubMed1994

Evaluation of chronic neurological sequelae after acute pesticide exposure using SPECT brain scans.

A case in which SPECT brain imaging was used in the diagnosis and treatment of chronic effects from acute acetylcholinesterase inhibitor poisoning is presented. The patient was exposed to an insecticide mixture containing phosphorothiate, pyrethrin, piperonyl butoxide, and petroleum distillates, which produced symptoms consistent with acute acetylcholinesterase inhibitor poisoning as well as an upper respiratory tract irritant. Delayed sequelae of gross neurologic symptoms followed, that is, coarse tremor, intermittent hemiballistic movements of the right arm and leg, flaccid muscular tone, fasciculations of muscle groups, muscle cramps, and sensory disturbances. A brain single-photon emission computerized tomography (SPECT) scan was performed 34 mo postexposure, revealing significantly decreased blood flow to the left temporal lobe and to the right and left basal ganglia. The patient's paresthesias were treated with phenytoin, which resulted in worsening of her movement disorder. A trial of amantadine and selegiline (Deprenyl) resulted in a dramatic reduction in dysfunctional movements and ataxia. Post amantadine and selegiline therapy, brain SPECT images revealed significantly improved blood flow with minimally decreased blood flow to the right and left basal ganglia. The use of SPECT scan techniques helped to elucidate objective chronic central nervous system effects subsequent to an acute insecticide exposure and also assisted in the evaluation of the effectiveness of therapeutic intervention.

Adult↗

PubMed1989

Monitoring for insecticide resistance in field-collected strains of the German cockroach (Dictyoptera: Blattellidae).

Forty-five field-collected strains of German cockroaches, Blattella germanica were tested for resistance to 12 different insecticides by the time-mortality response method in comparison with a known susceptible strain. Only low to moderate resistance to diazinon, chlorpyrifos, and acephate was detected. Resistance to malathion was widespread; about half of the strains tested showed high resistance. High resistance to the carbamates propoxur and bendiocarb also occurred. High resistance was uncommon with propoxur, but about 35 strains were highly resistant to bendiocarb. High resistance to pyrethrins was observed in about of the strains tested. Resistance to the pyrethroids allethrin, permethrin, phenothrin, fenvalerate, and cyfluthrin was detected in some of the strains examined. All of the strains tested were susceptible to one or more of the insecticides used. These results indicate that, although resistance is a serious problem in this species, satisfactory control should be possible by selection of an appropriate insecticide.

Animals↗

PubMed1990

Insecticide toxicity, synergism and resistance in the German cockroach (Dictyoptera: Blattellidae)

The toxicity of synergism of and resistance to insecticides in four strains of German cockroach, Blattella germanica (L.), were investigated. Toxicity of nine insecticides by topical application to the susceptible strain varied greater than 2,000-fold, with deltamethrin (LD50 = 0.004 micrograms per cockroach) and malathion (LD50 = 8.4 micrograms per cockroach) being the most and least toxic, respectively. Resistance to pyrethrins (9.5-fold) in the Kenly strain was unaffected by the synergists piperonyl butoxide (PBO) or S,S,S-tributylphosphorotrithioate (DEF), suggesting that the metabolism is not involved in this case. Malathion resistance in the Rutgers strain was suppressible with PBO, implicating oxidative metabolism as a resistance mechanism. The Ectiban-R strain was resistant to all the pyrethroids tested, and cypermethrin resistance was not suppressible with PBO or DEF. These findings support results of previous studies that indicated this train has a kdr-like mechanism. Bendiocarb resistance in both the Kenly and Rutgers strains was partially suppressed by either PBO or DEF, suggesting that oxidative and hydrolytic metabolism are involved in the resistance. Trends between the effects of the synergists on the susceptible versus resistant strains are discussed.

Animals↗

PubMed1991

Comparative toxicity of seven insecticides to immature stages of Musca domestica (Diptera: Muscidae) and two of its important biological control agents, Muscidifurax raptor and Spalangia cameroni (Hymenoptera: Pteromalidae).

The toxicity of seven insecticides was evaluated against unparasitized Musca domestica L. pupae and pupae parasitized by Muscidifurax raptor Girault & Sanders or Spalangia cameroni Perkins, two important biological control agents. Only pyrethrins + piperonyl butoxide (Pyrenone) was less toxic to M. raptor compared with house flies. Conversely, all of the insecticides except crotoxyphos were less toxic to S. cameroni compared with house flies. A plateau in the tetrachlorvinphos bioassay line for S. cameroni suggested that this colony had approximately 45% resistant individuals. The selectivity observed between immature stages of house flies and M. raptor or S. cameroni is different from that reported against adult stages of these same species, suggesting that selectivity of an insecticide varies considerably between different life stages.

Animals↗

PubMed1991

Control of American cockroaches (Dictyoptera: Blattidae) in sewers.

Baits, dusts, and aqueous sprays were applied to sewer shafts to control American cockroaches, Periplaneta americana (L). Boric acid and hydramethylnon baits failed to provide consistent control because of problems with mold on the baits and because large populations of cockroaches depleted the bait. Bendiocarb, boric acid powder, and a powder mixture of silica gel + synergized pyrethrins provided excellent control for at least 1 mo, but cockroaches reinfested treated shafts within 3-6 mo. Treatments made in the fall when adult cockroach populations were lowest (about 26%) provided best results. Aqueous sprays of wettable powder chlorpyrifos and microencapsulated diazinon provided outstanding control for at least 9 mo. Microencapsulated and emulsifiable concentrate chlorpyrifos sprays provided greater than 94% reductions for a year.

Animals↗

PubMed1987

Laboratory evaluation of cyromazine against insecticide-resistant field strains of Musca domestica.

A screening programme was undertaken to examine the possibility of cross resistance occurring between cyromazine and conventional insecticides. The responses of nine strains of Musca domestica to treatment with cyromazine, trichlorphon, methomyl and pyrethrins with piperonyl butoxide were measured. No tolerance to cyromazine was found, neither was there a direct correlation between larval responses to cyromazine and adult responses to other insecticides. Cyromazine is a potent larvicide against M. domestica and the results of these tests show that it has good potential for the control of houseflies with high levels of resistance to other insecticides.

Animals↗