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Objective To determine the synergists action of piperonyl butoxide (PBO) and S,S,S-tributyl phosphorotrithioate (DEF) on toxicity of carbamate insecticides against Blattella germanica in Tehran city. Methods In the current study, German cockroach strains were collected from several hospitals and dormitories in Tehran. At the beginning, different concentrations of bendiocarb and carbaryl (insecticides belong to carbamate group) were determined by surface contact on a susceptible strain. Then, the level of susceptibility and type of resistance mechanisms in the collected strains from contaminated sites to the aforementioned insecticides were studied by using PBO and DEF synergists with different insecticide ratios to synergist (1:0, 1:1, 1:2, 1:3). Results The DEF synergist along with bendiocarb and carbaryl completely eliminated the resistance in all strains but PBO did not completely eliminate the resistance in the strains of Mofid, Alvand, Valiasr hospitals and Shariati dormitory. Generally, the impact of DEF was observed in the removing resistance more than PBO. Conclusions In most of these strains, resistance to bendiocarb and carbaryl is completely eliminated by DEF, showing a very high role of estraze enzymes in resistance to bendiocarb and carbaryl. But in most strains PBO does not remove the resistance because other mechanisms, such as reduced cuticle penetration and insensitivity to the acetylcholine esterase enzyme, may be involved.
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OBJECTIVE@#To determine the synergists action of piperonyl butoxide (PBO) and S,S,S-tributyl phosphorotrithioate (DEF) on toxicity of carbamate insecticides against Blattella germanica in Tehran city.@*METHODS@#In the current study, German cockroach strains were collected from several hospitals and dormitories in Tehran. At the beginning, different concentrations of bendiocarb and carbaryl (insecticides belong to carbamate group) were determined by surface contact on a susceptible strain. Then, the level of susceptibility and type of resistance mechanisms in the collected strains from contaminated sites to the aforementioned insecticides were studied by using PBO and DEF synergists with different insecticide ratios to synergist (1:0, 1:1, 1:2, 1:3).@*RESULTS@#The DEF synergist along with bendiocarb and carbaryl completely eliminated the resistance in all strains but PBO did not completely eliminate the resistance in the strains of Mofid, Alvand, Valiasr hospitals and Shariati dormitory. Generally, the impact of DEF was observed in the removing resistance more than PBO.@*CONCLUSIONS@#In most of these strains, resistance to bendiocarb and carbaryl is completely eliminated by DEF, showing a very high role of estraze enzymes in resistance to bendiocarb and carbaryl. But in most strains PBO does not remove the resistance because other mechanisms, such as reduced cuticle penetration and insensitivity to the acetylcholine esterase enzyme, may be involved.
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Objective: To investigate what kind of mosquito sample is necessary for the determination of insecticide susceptibility in malaria vectors. Methods:Larvae and pupae of Anopheles gambiae s.l. (An. gambiae) mosquitoes were collected from the breeding sites in Littoral and Oueme departments. The Centers for Disease Control and Prevention (CDC) susceptibility tests were conducted on unfed male and female mosquitoes aged 2-5 days old. CDC susceptibility tests were also conducted on unfed, blood fed and gravid female mosquitoes aged 2-5 days old. These susceptibility tests were also conducted on unfed and blood fed female mosquitoes aged 2-5 days old and 20 days old. CDC biochemical assay using synergist was also carried out to detect any increase in the activity of enzyme typically involved in insecticide metabolism. Results:Female An. gambiae Ladji and Sekandji populations were more susceptible than the males when they were unfed and aged 2-5 days old. The mortality rates of blood fed female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when females were unfed. In addition, the mortality rates of gravid female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when they were unfed. The mortality rate obtained when female An. gambiae Sekandji populations were unfed and aged 20 days old was higher than the one obtained when these populations were unfed and aged 2-5 days old. The results obtained after effects of synergist penicillin in beeswax on F1 progeny of An. gambiae Ladji populations resistant to permethrin showed that mono-oxygenases were involved in permethrin resistant F1 progeny from Ladji. Conclusions: The resistance is a hereditary and dynamic phenomenon which can be due to metabolic mechanisms like overproduction of detoxifying enzymes activity. Many factors influence vector susceptibility to insecticide. Among these factors, there are mosquito sex, mosquito age, its physiological status. Therefore, it is useful to respect the World Health Organization criteria in the assessment of insecticide susceptibility tests in malaria vectors. Otherwise, susceptibility testing is conducted using unfed female mosquitoes aged 3-5 days old. Tests should also be carried out at (25±2) °C and (80±10)% relative humidity.
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<p><b>OBJECTIVE</b>To investigate what kind of mosquito sample is necessary for the determination of insecticide susceptibility in malaria vectors.</p><p><b>METHODS</b>Larvae and pupae of Anopheles gambiae s.l. (An. gambiae) mosquitoes were collected from the breeding sites in Littoral and Oueme departments. The Centers for Disease Control and Prevention (CDC) susceptibility tests were conducted on unfed male and female mosquitoes aged 2-5 days old. CDC susceptibility tests were also conducted on unfed, blood fed and gravid female mosquitoes aged 2-5 days old. These susceptibility tests were also conducted on unfed and blood fed female mosquitoes aged 2-5 days old and 20 days old. CDC biochemical assay using synergist was also carried out to detect any increase in the activity of enzyme typically involved in insecticide metabolism.</p><p><b>RESULTS</b>Female An. gambiae Ladji and Sekandji populations were more susceptible than the males when they were unfed and aged 2-5 days old. The mortality rates of blood fed female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when females were unfed. In addition, the mortality rates of gravid female An. gambiae Ladji and Sekandji populations aged 2-5 days old were lower than those obtained when they were unfed. The mortality rate obtained when female An. gambiae Sekandji populations were unfed and aged 20 days old was higher than the one obtained when these populations were unfed and aged 2-5 days old. The results obtained after effects of synergist penicillin in beeswax on F1 progeny of An. gambiae Ladji populations resistant to permethrin showed that mono-oxygenases were involved in permethrin resistant F1 progeny from Ladji.</p><p><b>CONCLUSIONS</b>The resistance is a hereditary and dynamic phenomenon which can be due to metabolic mechanisms like overproduction of detoxifying enzymes activity. Many factors influence vector susceptibility to insecticide. Among these factors, there are mosquito sex, mosquito age, its physiological status. Therefore, it is useful to respect the World Health Organization criteria in the assessment of insecticide susceptibility tests in malaria vectors. Otherwise, susceptibility testing is conducted using unfed female mosquitoes aged 3-5 days old. Tests should also be carried out at (25±2) °C and (80±10)% relative humidity.</p>
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Objective To prepare the Fe3O4 loaded polymer microspheres(Fe3O4/PLGA),and to investigate the influence of Fe3O4/PLGA combined with high-intensity focused ultrasound (HIFU) on rabbits bearing breast tumor.Methods Double emulsion method were utilized to prepare the Fe3O4/PLGA.14 days after implantation of VX2 tumor in breast,32 rabbits were randomly divided into four equal groups.In group Ⅱ,Ⅲ,and Ⅳ,the rabbits received a percutaneous injection of 0.5 ml saline,PLGA,and Fe3O4/PLGA microcapsules solution into breast tumor at 3,6,9,12 dots,about 3 mm around the tumor respectively,and massaged for 1 min before receiving HIFU ablation,while HIFU group received HIFU ablation only.HIFU ablation parameters were the same:ablated-dot mode,acoustic power 150 W,exposure duration 5 s.After HIFU ablation,the volume of coagulative necrosis was calculated,HE staining,TEM and immunohistochemical examination of PCNA were performed to detect the structure changes of the targeted tissue caused by HIFU ablation.Results The volume of coagulative necrosis caused by HIFU ablation was substantially larger and the positive index of PCNA was lower in the necrotic region after the injection of Fe3O4/PLGA microcapsules compared to the group without injection agents,the group of saline and the group of pure PLGA microspheres under the same irritation(P ＜0.05).Pathological examination demonstrated the targeted tissue was destroyed severely,Fe3O4 nanoparticles were seen depositing in residual tumor cells under TEM.Conclusions The self-made Fe3O4/PLGA microspheres can effectively enhanced the biomedical effect of HIFU surgery on rabbits bearing VX2 breast tumor.