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PubMed1984

Nature of N-nitrosodimethylamine demethylase in hepatic microsomes of rats.

The nature of enzymes involved in demethylation of N-nitrosodimethylamine (NDMA) was investigated in hepatic microsomes of rats. Compared to the other cytochrome P-450-dependent enzymes. NDMA demethylase had anomalous properties as reported in the literature. However, kinetic analysis suggested a qualitative change in NDMA demethylase induced by phenobarbital (PB) and 3-methylcholanthrene (MC) pretreatment. The inhibition of demethylase by alpha-naphthoflavone in MC-treated microsomes also suggested that cytochrome P-450 species induced by MC are active in demethylating NDMA. The enhancement of NDMA demethylase activity by metyrapone in PB-treated microsomes was greater than in non-treated ones, and was not observed in MC-treated ones. The result is almost the same as in acetanilide hydroxylation, depending on cytochrome P-450. Pyrazole, tranylcypromine, and aminoacetonitrile, which are selective inhibitors of NDMA demethylation, interacted with cytochrome P-450 species to produce type-II spectra, and typical type-II compounds (aniline, imidazole, and nicotinamide) were inhibitors of the NDMA demethylation. Tranylcypromine irreversibly inhibited microsomal monoamine oxidase [EC 1.4.3.4], but not NDMA demethylase. Semicarbazide (a copper- and pyridoxal-containing amine oxidase [EC 1.4.3.6] inhibitor) had no effect on demethylation. From these results it is concluded that NDMA demethylation depends only on cytochrome P-450-dependent monooxygenases.

Aminoacetonitrile↗
PubMed1983

Mechanism of formation of mercapturic acids from aromatic aldehydes in vivo.

Male adult Wistar rats dosed i.p. with o-substituted benzaldehydes (o-F, o-Cl, and o-Br = V, VI, and VII) excreted mercapturic acids in urine. These acids were identified as N-acetyl-S-(ortho-substituted benzyl)cysteines (I, II, III). The total mercapturic acid excretion as % dose (2.0 mmol/kg, n = 4) was 1.2 +/- 0.4, 6.8 +/- 0.9, and 10.4 +/- 2.0 for V, VI, and VII. p-Cl-benzaldehyde administered in the same dose showed a non-significant urinary thioether excretion. The aim of the investigation was to prove in vivo a postulated metabolic pathway of substituted benzaldehydes via sulphate esters to mercapturic acids. After a single administration of the sodium salts of o- and p-Cl-benzylsulfuric acid a significant increase in mercapturic acid excretion of 21.2 +/- 1.8% and 14.5 +/- 1.2% of dose (2.0 mmol/kg, n = 4) was found. By pretreatment with pyrazole the mercapturic acid excretion increased after administration of o-Cl-benzyl alcohol (IX) whereas a significant decrease was found after administration of o-Cl-benzaldehyde (VI). After simultaneous administration of ethanol with IX and VI an increase in mercapturic acid excretion was observed. After previous administration of pentachlorophenol a significant decrease in urinary mercapturic acid excretion for IX and VI was found. These findings are in accordance with a metabolic pathway of substituted benzaldehydes via benzyl alcohols, subsequently sulphate esters to the corresponding benzylmercapturic acids.

Acetylcysteine↗
PubMed1986

Studies on the metabolic activation of diethanolnitrosamine in animal-mediated and in vitro assays using Escherichia coli K-12 343/113 as an indicator.

The mutagenic activity of diethanolnitrosamine (NDELA), a carcinogenic compound which leads to inconsistent results in standard in vitro procedures was tested in vitro and in animal-mediated assays with the indicator strain Escherichia coli (E. coli) K-12 343/113. This strain allows the simultaneous detection of forward and back mutations arising in several genes of the E. coli chromosome. In animal-mediated assays in which mice were used as hosts for i.v. injected E. coli indicator cells, s.c. application of NDELA induced a dose dependent increase of galactose fermenting mutants in cells recovered from the livers of animals exposed for 3 h to the mutagen. Comparison with results obtained with diethylnitrosamine (DENA) in the same test system revealed that the two compounds apparently cause different types of mutagenic lesions. Induction of arg+ mutations by DENA and several other aliphatic nitrosamines is mainly due to base pair substitutions, whereas NDELA is rather mutagenic in the galRs system. This latter system is, in addition, sensitive to frameshifts and deletions. These differences in mutagenic specificity suggest that NDELA and DENA, although structurally closely related, are activated via different molecular mechanisms. In fact, evidence is accumulating that alcohol dehydrogenase (ADH) could be involved in the activation of NDELA. On the other hand, the effective mutagenesis of NDELA obtained in vitro with E. coli upon addition of rat liver microsomal fraction would not be expected if ADH is involved in the activation since the S-9 Mix used in the present experiments was devoid of cofactors (NAD, NADP), necessary to accomplish oxidation by ADH. Therefore, further in vivo studies were performed, in which pyrazole, a potent blocker of ADH, was administered prior (1 and 24 h) to the injection of the mutagen. The observation that a dose dependent increase of mutants in the liver (and to a lower extent in the spleens) of treated animals takes place under conditions in which ADH activity is blocked, whereas several microsomal enzymes are stimulated, indicated that besides oxidation of NDELA by ADH other metabolic activation pathways are involved. Apparently enzymes contained in the liver homogenate, possibly NADPH dependent enzymes of the microsomal ethanol oxidizing system, play an important role in the formation of mutagenic metabolites of NDELA.

Animals↗
PubMed1981

Antifungal properties of some pyrazolyl-alkyl-sulfides. Electron microscopic evidence in two dermatophytes and Candida albicans.

Four 5-amino-4-alkylthio-pyrazoles were synthesized and their antifungal activity was evaluated in vitro in Trichophyton mentagrophytes, Microsporum cookei and Candida albicans. The compounds slightly influenced the growth kinetics of the yeast, but at concentrations ranging from 20 to 40 micrograms/ml completely prevented the mycelial growth of the two dermatophytes cultivated on Sabouraud's agar medium. An electron microscopic study, undertaken by using the most active compound, showed that in C. albicans mitochondria were the only cell targets affected whereas in the dermatophytes cell wall, plasmalemma and the main cytoplasmic organelles were damaged in various degrees. Since the most remarkable alterations were connected with membrane abnormalities, the cytological changes observed were tentatively interpreted as a consequence of the compound intrusion into the lipid bilayer of the membranes, since the drug is lipophilic in nature.

Antifungal Agents↗
PubMed1976

Mepiprazole, a new psychotropic drug: effects on uptake and retention of monoamines in rat brain synaptosomes.

The influence of mepiprazole (EMD 16,923), a new pyrazol-ylalkyl-piperazine derivative, on the uptake of 3H-norepinephrine (NE), 3H-dopamine (DA), and 3H-serotonin (5-HT) into rat brain synaptosomes from cerebral cortex, corpus striatum, and hypothalamus was investigated in comparison with several psychotropic drugs, including oxypertine, d-amphetamine, imipramine, desipramine, chlorimipramine, amitriptyline, and chlorpromazine in vitro. Mepiprazole was a relatively weak inhibitor of monoamine uptake and exhibited its strongest action on the hypothalamic 5-HT uptake, being almost equipotent with desipramine (IC50 = 0.9 MUM). Furthermore, the influence of the drugs on the retention of 3H-amines previously taken up by whole rat brain synaptosomes was studied. Unlike the tricyclic antidepressants, mepiprazole as well as oxypertine and d-amphetamine markedly increased the efflux of radioactivity during a 20-min incubation at 37 degrees C at low concentrations (10(-6) to 10(-5) M), whereas at 10(-4) M all drugs greatly enhanced the efflux. The ability of mepiprazole to increase 5-HT concentration at the receptor level by a combination of neuronal uptake inhibition and release is discussed in relationship to the central actions of the drug.

Animals↗
PubMed1976

Regulation of enzymes of ethanol metabolism in yeast (Rhodotorula gracilis).

The three enzymes of ethanol metabolism alcohol dehydrogenase, aldehyde dehydrogenase and acetyl-CoA synthetase in the obligate aerobic yeast Rhodotorula gracilis are repressed by glucose and induced by C2 metabolic fuels with a regulatory pattern indicating a correlation in the control mechanisms. To try an identification of the molecular signals involved in the transmission of the inducing stimulus, experiments were carried out by blocking with 2 mM pyrazole the ethanol acetaldehyde metabolic step. Results indicate that ethanol is not specifically required as a molecular signal for induction.

Acetaldehyde↗
PubMed1990

FPL 62064, a topically active 5-lipoxygenase/cyclooxygenase inhibitor.

FLP 62064 [N-(4-methoxyphenyl)-1-phenyl-1H-pyrazole-3-amine] is a dual inhibitor of prostaglandin synthetase and 5-lipoxygenase. The compound had anti-inflammatory activity in vivo in a number of models. It inhibited peritoneal inflammation induced by immune-complex when given locally. When applied to the skin, FPL 62064 inhibited UV irradiation-induced erythema and PGE2 formation in the guinea pig and also oedema formation and eicosanoid production in the mouse ear produced by arachidonic acid. Co-injected with arachidonic acid in rabbit skin, FPL 62064 inhibited oedema and eicosanoid formation.

Administration, Cutaneous↗
PubMed1995

Extracellular ascorbate stabilization as a result of transplasma electron transfer in Saccharomyces cerevisiae.

The presence of yeast cells in the incubation medium prevents the oxidation of ascrobate catalyzed by copper ions. Ethanol increases ascorbate retention. Pyrazole, an alcohol dehydrogenase inhibitor, prevents ascorbate stabilization by cells. Chelation of copper ions does not account for stabilization, since oxidation rates with broken or boiled cells or conditioned media are similar to control rates in the absence of cells. Protoplast integrity is needed to reach optimal values of stabilization. Chloroquine, a known inhibitor of plasma membrane redox systems, inhibits the ascorbate stabilization, the inhibition being partially reversed by coenzyme Q6. Chloroquine does not inhibit ferricyanide reduction. Growth of yeast in iron-deficient media to increase ferric ion reductase activity also increases the stabilization. In conclusion, extracellular ascorbate stabilization by yeast cells can reflect a coenzyme Q dependent transplasmalemma electron transfer which uses NADH as electron donor. Iron deficiency increases the ascorbate stabilization but the transmembrane ferricyanide reduction system can act independently of ascorbate stabilization.

Ascorbic Acid↗
PubMed1996

Effects of the cannabinoid CB1 receptor antagonist SR141716A on the behavior of pigeons and rats.

SR141716A (Sanofi Recherche), a pyrazole derivative with high affinity for rat and human CB1 cannabinoid receptors, has recently been reported to reverse biochemical, physiological and behavioral effects induced by cannabinoid agonists. The present experiments characterized the activity of SR141716A (SR) in behavioral procedures designed to assess its antagonistic and intrinsic effects on unconditioned behavior and on complex learned behaviors. Six adult male pigeons were trained to discriminate injections of 0.56 mg/kg delta 9-tetrahydrocannabinol (delta 9-THC) from vehicle under a two-key, fixed-ratio schedule of food reinforcement. SR (IM) produced a nearly complete blockade of THC-appropriate responding occasioned by the training dose without inducing significant changes in session response rates, but also produced partial substitution for delta 9-THC when administered alone. In another group of pigeons trained under a multiple schedule of signaled and unsignaled fixed consecutive number (FCN) responding, SR had little effect on accuracy, but delta 9-THC produced dose-related decreases in accuracy under both schedule components. SR was also evaluated in acoustic startle procedures in rats. SR produced little effect either on startle amplitude or prepulse inhibition of acoustic startle. In contrast, the potent cannabinomimetic CP-55, 940 produced large decreases in startle responses elicited by 120 dB [A] broad-band noise. These decreases were completely reversed by SR (10 mg/kg, IP). In concurrent measures, SR blocked the hypothermic effect CP-55,940. These results suggest that SR is an effective antagonist of the psychoactive effects of cannabinoids.

Animals↗
PubMed1990

Effect of ribonucleotide reductase inhibitors on the growth of human colon carcinoma HT-29 cells in culture.

The effects of ribonucleotide reductase inhibitors on the growth of the human colon carcinoma cell line HT-29 were examined. Inhibitors were chosen for these studies that were specifically directed at each of the subunits of ribonucleotide reductase. The concentrations of drugs required to inhibit the growth of HT-29 cells by 50% (IC50) for hydroxyurea, 2,3-dihydro-lH-pyrazole-[2,3a]imidazole (IMPY), and 4-methyl-5-amino-l-formyl-isoquinoline thiosemicarbazone (MAIQ) were 206, 996, and 3.2 microM, respectively. Although the IC50 for deoxyadenosine alone was greater than 2,000 microM, in the presence of 5 microM erythro-9-(2-hydroxy-3-nonyl)adenine (EHNA), which protects deoxyadenosine from deamination by adenosine deaminase, it was reduced to 112 microM. The IC50 for deoxyguanosine was 1,060 microM. The addition of 8-aminoguanosine to protect deoxyguanosine from phosphorolysis by purine nucleoside phosphorylase did not increase the toxicity of deoxyguanosine in HT-29 cells. The combination of MAIQ or IMPY and deoxyadenosine/EHNA gave strong synergistic inhibition of HT-29 cell growth. The results of these studies indicate that ribonucleotide reductase inhibitors effectively block the growth of human colon carcinoma HT-29 cells and that combinations of inhibitors directed at the individual subunits of reductase result in synergistic inhibition of HT-29 cell growth in culture.

Adenine↗
PubMed2005

Synthesis, analgesic, and anti-inflammatory activities of [6-(3,5-dimethyl-4-chloropyrazole-1-yl)-3(2H)-pyridazinon-2-yl]acetamides.

A series of structurally diverse amide derivatives of [6-(3,5-dimethyl-4-chloro-pyrazole-1-yl)-3(2H)-pyridazinone-2-yl]acetic acid were prepared and tested for their in vivo analgesic and anti-inflammatory activity by using p-benzoquinone-induced writhing test and carrageenan-induced hind paw edema model, respectively. The analgesic and anti-inflammatory activity of the compounds, 7c, 7d and 7k were found to be equipotent to aspirin (as an analgesic) and indometacin (as an anti-inflammatory drug), respectively. The other amide derivatives generally resulted in lower activity on comparision with reference compounds.

Acetamides↗
PubMedDate not supplied

Oral bioavailability and pharmacokinetics of DRF-4367, a new COX-2 inhibitor in rats.

The pharmacokinetic characterization of DRF-4367 (a new diaryl pyrazole derivative), a potent selective COX-2 inhibitor was performed in Wistar rats. In the first study, a single dose of 2, 5, 10, 30 or 100 mg/kg DRF-4367 was given orally to rats for investigating the dose proportionality and/or linearity in the pharmacokinetics. In the second study, a single intravenous bolus dose of DRF-4367 was given at a dose of 10 mg/kg to calculate the absolute oral bioavailability, clearance and volume of distribution parameters. Blood samples were drawn at predetermined intervals up to 24 h post-dose. The concentrations of DRF-4367 in various plasma samples were determined by a validated HPLC method. Plasma concentration versus time data was generated following oral and i.v dosing and subjected to a noncompartmental pharmacokinetic analysis. Following oral administration, maximum concentrations of DRF-4367 were achieved at about 3 h and were unchanged with incremental doses. Both Cmax and AUC0-infinity appeared to increases less than proportional to the administered oral doses. While the doses increased in the ratio of 1.0 : 2.5 : 5.0 : 15.0 : 50.0, the mean AUC0-infinity and Cmax increased in the ratios of 1.0 : 2.8 : 4.5 : 8.6 : 14.5 and 1 : 2.4 : 4.1 : 6.2 : 8.3, respectively. Following i.v. administration, the concentration of DRF4367 declined in a monoexponential fashion with terminal elimination half-life of 5.7 h. The systemic clearance and volume of distribution of DRF-4367 in rats were 0.36 L/h/Kg and 2.2 L/Kg respectively after i.v administration. Elimination half-life was unchanged with route of administration and with increase in oral doses. Absolute oral bioavailability of DRF-4367 in the efficacy dose range was 70-80%.

Administration, Oral↗
PubMed1998

ER-34122, a novel dual 5-lipoxygenase/cyclooxygenase inhibitor with potent anti-inflammatory activity in an arachidonic acid-induced ear inflammation model.

OBJECTIVE AND DESIGN: To investigate the effect of ER-34122, a novel pyrazole derivative, on 5-lipoxygenase (LOX) and cyclooxygenase (COX) metabolite production in vitro, ex vivo and in vivo. MATERIAL: In vitro, lysate of rat basophilic leukemia cells, the microsome fraction of sheep seminal vesicles, human polymorphonuclear leukocytes, human synovial cells, and human monocytes. Ex vivo and in vivo, male Balb/c mice or SD rats. TREATMENT: In ex vivo study, ER-34122 (0.03-1 mg/kg) was orally administered 1 h before withdrawal of blood samples. In carrageenin-induced paw edema, ER-34122 (3-100 mg/kg) and indomethacin (1-10mg/kg) were orally administered 1 h before carrageenin injection. In arachidonic acid-induced ear inflammation, ER-34122 (0.3-10mg/kg), zileuton (10-100mg/kg) and indomethacin (0.3-3mg/kg) were orally administered 1 h before arachidonic acid application. METHODS: 5-Hydroxyeicosatetraenoic acid and other eicosanoids were determined by using an HPLC method and enzyme immunoassay, respectively. Rat hind paw edema and mouse ear edema were assessed by measuring paw volume and ear thickness, respectively. Myeloperoxidase (MPO) activity and eicosanoid content of the ear tissue were also determined. RESULTS: ER-34122 inhibited both LOX and COX product generation in vitro, and ex vivo. ER-34122 and indomethacin inhibited carrageenin-induced paw edema formation. In the arachidonic acid-induced ear inflammation, ER-34122 inhibited inflammatory responses (edema formation and MPO accumulation) as well as eicosanoids (LTB4, LTC4 and PGE2) generation. A representative LOX inhibitor, zileuton, also inhibited these inflammatory responses, while a COX inhibitor, indomethacin, did not suppress them though it completely inhibited PGE2 generation. CONCLUSIONS: The anti-inflammatory characteristics of ER-34122 are considered to be superior to those of COX inhibitors such as indomethacin, because in addition to its inhibitory activity on the COX pathway, ER-34122 inhibits LOX products generation, as revealed by the inhibition of edema formation or polymorphonuclear leukocyte infiltration in the arachidonic acid-induced ear inflammation model.

Animals↗
PubMed2004

Preliminary in vivo pharmacokinetic and pharmacodynamic evaluation of a novel calcineurin-independent inhibitor of NFAT.

A-285222 (A-285) is a bis-trifluoromethyl-pyrazole (BTP), a novel class of immunosuppressive agents that inhibit NFAT activity in vitro in human and non-human primate cells through a calcineurin-independent mechanism. In this preliminary study, we treated cynomolgus monkeys with different doses of A-285 for several days. Blood was collected from all animals at different times during the study. From these samples, plasma concentrations of A-285 were measured by liquid chromatography/mass spectrometry (LC/MS), and intracellular T-cell production of the cytokines IL-2, IFN-gamma, and TNF-alpha was quantified by flow cytometry using a mitogen-stimulated whole blood assay. Marked inhibition of cytokine production occurred after administration of the first dose of A-285, and this effect was comparable to that of cyclosporine. While neurological toxic side effects were seen when the plasma concentration of A-285 exceeded 4 microg/ml, at lower plasma levels the drug was well tolerated over 2 weeks and its pharmacodynamic effects were sustained throughout this time.

Administration, Oral↗
PubMed1995

2-Butoxyethanol autoprotection is due to resiliance of newly formed erythrocytes to hemolysis.

Pretreatment with a low dose of a toxic chemical protecting the animals from a subsequently administered lethal dose of the same chemical is called autoprotection. Autoprotection by model hepatotoxicants has been recently shown to be due to augmentation of cell division and tissue repair as well as an inherent resiliance of newly divided cells. The present studies were designed to investigate if an autoprotection model could be established in an extrahepatic tissue. The second objective was to test the hypothesis that inherent resiliance of newly divided cells is a major contributing mechanism for autoprotection. Female Sprague-Dawley rats (200-250 g) received a single administration of a moderately toxic but nonlethal dose (500 mg/kg, p.o.) 7 days prior to the administration of an LD90 dose (1500 mg/kg, p.o.) of the same compound. All rats receiving the initial protective dose are able to survive the lethal dose of butoxyethanol, in contrast to the death of those receiving the lethal dose alone. Following the administration of butoxyethanol, the hematocrit decreased from the normal 45% to 18% and by day 7, recovered to normal levels. Following the lethal challenge, hematocrit decreased to 13% in the naive rats, while decreasing only to 27% in rats receiving the protective dose, permitting animal survival. Administration of pyrazole to inhibit metabolism of butoxyethanol to butoxyacetic acid abolished autoprotection.(ABSTRACT TRUNCATED AT 250 WORDS)

Aldehyde Dehydrogenase↗
PubMed1998

In vitro studies of human alcohol dehydrogenase inhibition in the process of methanol and ethylene glycol oxidation.

The liver is the major organ responsible for methanol and ethylene glycol oxidation, and alcohol dehydrogenase (alcohol: NAD+ oxidoreductase, EC 1.1.1.1.) is the main enzyme involved. In the present study, alcohol dehydrogenase (ADH) activity was measured spectrophotometrically in vitro at physiological pH 7.4 and 37 degrees C using human enzyme hepatic fraction. The percentage of residual activity was calculated for four inhibitors at concentrations of 10(-3), 10(-4), and 10(-5) M (pyrazole, 4-methylpyrazole, cimetidine, theophylline) and methylene blue at concentrations 10(-4) and 10(-5) M. Our results have shown that the best inhibitor, cimetidine, decreased oxidation of 0.1 M and 0.05 M methanol to 24 and 29% respectively at a drug concentration of 1 mM. Reaction with 0.1 M ethylene glycol as the ADH substrate was blocked by the same substances and 4-methylpyrazole was found to be a highly effective inhibitor.

Alcohol Dehydrogenase↗
PubMed2000

Effects of 2-arachidonylglycerol, an endogenous cannabinoid, on neuronal activity in rat hippocampal slices.

The monoacylglycerol 2-arachidonylglycerol is an endogenous ligand of cannabinoid receptors. We examined whether 2-arachidonylglycerol can influence excessive neuronal activity by investigating stimulation-induced population spikes and epileptiform activity in rat hippocampal slices. For this purpose, the effects of 2-arachidonylglycerol were compared with those of the synthetic cannabinoid agonist WIN 55,212-2. At concentrations of 10-50 microM, 2-arachidonylglycerol attenuated the amplitude of the orthodromic population spike and the slope of the field excitatory postsynaptic potential (field EPSP). However, the effect of the synthetic cannabinoid WIN 55,212-2 (R(+)-[2,3-dihydro-5-methyl-3-[(morpholinyl)methyl]pyrrolol[ 1,2,3-de]-1,4-benzoxazinyl]-(1-naphthalenyl)methanone; 0.1 microM and 1 microM) was significantly higher than that of the endogenous ligand. At a concentration of 1 microM, WIN 55,212-2 completely suppressed the field EPSP. However, none of the investigated compounds did affect the presynaptic fiber spike of the afferents. The CB1 receptor antagonist SR 141716 (N-piperidino-5-(4-chlorophenyl)-1-(2,4-dichlorphenyl)-4-methyl-3- pyrazole-carboxamide) blocked the inhibition evoked by the cannabinoids. Both 2-arachidonylglycerol (30 microM) and WIN 55,212-2 (100 nM) shifted the input-output curve of the postsynaptic spike and the field EPSP to the right and increased the magnitude of paired-pulse facilitation, indicating a presynaptic mechanism of action. 2-Arachidonylglycerol and WIN 55,212-2 attenuated the frequency of spontaneously occurring epileptiform burst discharges in CA3 elicited by omission of Mg2+ and elevation of K+ to 8 mM. The antiepileptiform effect of these cannabinoids was blocked by SR 141716. In conclusion, 2-arachidonylglycerol seems to limit neuronal excitability via cannabinoid receptors of the CB1 type. By acting predominantly at a presynaptic site, it is capable of reducing excitatory neurotransmission, a mechanism which might be involved in the prevention of excessive excitability leading to epileptiform activity.

Analgesics↗
PubMed1997

Impacts on nontarget insects of a new insecticide compound used against the desert locust [Schistocerca gregaria (Forskål 1775)].

In 1994, the effects of fipronil, a new insecticide compound of the phenyl-pyrazol chemical group, was tested against desert locusts during a field experiment in Mauritania. The impacts of these spray treatments on nontarget Coleoptera and Hymenoptera were also studied. In relation to organophosphorous insecticides usually used against grasshoppers and locusts, fipronil appeared more effective and persistent. Similar results were obtained for nontarget Carabidae and Tenebrionidae which were almost totally eliminated from the treated plot. The effects on Hymenoptera varied according the family; Scelionidae and Sphecidae seemed to be more affected than Apoidea. Positive and negative aspects of fipronil treatments are discussed. Appearing as one of the most convenient insecticides to successfully prevent locust outbreaks, at a very early stage of invasion under Saharan conditions, fipronil simultaneously induces heavy mortality in some nontarget insect groups.

Africa, Northern↗