CONTROL OF INSECTICIDE EXPOSURE IN EMPLOYMENT—A Guide to Physicians for Dealing with Organic Phosphates

Increasingly larger amounts of the highly efficient and highly toxic organic phosphate insecticides, particularly parathion, tetraethyl pyrophosphate, and Systox (demeton), are being applied on California''s farms. These insecticides have become an economic necessity to agriculture. They can be used safely when rigid precautions are utilized and when medical supervision is provided for employees regularly working with these chemicals.The demand for the services of physicians prepared to supply this kind of industrial medical supervision is expected to increase in California.The basic procedures through which effective medical supervision can be provided are outlined.     

Utilizing the assassin bug, Pristhesancus plagipennis (Hemiptera: Reduviidae), as a biological control agent within an integrated pest management programme for Helicoverpa spp. (Lepidoptera: Noctuidae) and Creontiades spp. (Hemiptera: Miridae) in cotton

Helicoverpa spp. and mirids, Creontiades spp., have been difficult to control biologically in cotton due to their unpredictable temporal abundance combined with a cropping environment often made hostile by frequent usage of broad spectrum insecticides. To address this problem, a range of new generation insecticides registered for use in cotton were tested for compatibility with the assassin bug, Pristhesancus plagipennis (Walker), a potential biological control agent for Helicoverpa spp. and Creontiades spp. Indoxacarb, pyriproxifen, buprofezin, spinosad and fipronil were found to be of low to moderate toxicity on P. plagipennis whilst emamectin benzoate, abamectin, diafenthiuron, imidacloprid and omethaote were moderate to highly toxic. Inundative releases of P. plagipennis integrated with insecticides identified as being of low toxicity were then tested and compared with treatments of P. plagipennis and the compatible insecticides used alone, conventionally sprayed usage practice and an untreated control during two field experiments in cotton. The biological control provided by P. plagipennis nymphs when combined with compatible insecticides provided significant (P<0.001) reductions in Helicoverpa and Creontiades spp. on cotton and provided equivalent yields to conventionally sprayed cotton with half of the synthetic insecticide input. Despite this, the utilization of P. plagipennis in cotton as part of an integrated pest management programme remains unlikely due to high inundative release costs relative to other control technologies such as insecticides and transgenic (Bt) cotton varieties.     

基于信息化平台的临床科室精准管理探索

精准医学时代,临床科室的“精准管理”是应用高度结构化、自动化、精准化的信息管理平台进行科室的全面监管和预警,能够通过精准预测,精准监督,精准定位来提高预测准确性和预测能力,制定合理有效的计划目标,规范医疗诊疗行为,改进医疗服务流程,提高科研效率质量以及有针对性地进行人才培养和个性化教学管理,在医院的科室管理中具有较好的临床应用性及推广价值。     

Synergistic efficacy of botanical blends with and without synthetic insecticides against Aedes aegypti and Culex annulirostris mosquitoes.

Increasing insecticide resistance requires strategies to prolong the use of highly effective vector control compounds. The use of combinations of insecticides with other insecticides and phytochemicals is one such strategy that is suitable for mosquito control. In bioassays with Aedes aegypti and Culex annulirostris mosquitoes, binary mixtures of phytochemicals with or without synthetic insecticides produced promising results when each was applied at a LC25 dose. All mixtures resulted in 100% mortality against Cx. annulirostris larvae within 24 h rather than the expected mortality of 50%. All mixtures acted synergistically against Ae. aegypti larvae within the first 24 h except for one mixture that showed an additive effect. We conclude that mixtures are more effective than insecticides or phytochemicals alone and that they enable a reduced dose to be applied for vector control potentially leading to improved resistance management and reduced costs.     

Efficacy of simulated barrier treatments against laboratory colonies of Pharaoh ant

Five selected insecticides were applied to four substrates and evaluated in laboratory studies for repellency and toxicity against the Pharaoh ant, Monomorium pharaonis (L.). We tested both repellent and nonrepellent formulations on outdoor (concrete and mulch) and indoor (ceramic and vinyl) substrates. Repellency was evaluated using a behavioral bioassay in which colonies were given a choice to leave the treated zone and move into empty nests provided in the untreated zone. We used a novel experimental design whereby ants walked on a Slinky coil suspended from a metal support frame, thus permitting a long foraging distance with a minimum use of space and resources. Cypermethrin, a repellent pyrethroid insecticide, resulted in colony budding, although the response was delayed. Toxicity of insecticides was evaluated as worker, queen, and brood mortality. The most effective treatment was fipronil, which provided 100% reduction in pretreatment activity by 2 d posttreatment on both concrete and mulch. Chlorfenapyr was highly effective on both outdoor and indoor substrates. Significant substrate effects were observed with insecticides applied to nonabsorbent substrates (ceramic tile), which performed better than insecticides applied to absorbent substrates (vinyl tile). Other highly absorbent materials (mulch and concrete), however, did not reduce insecticide efficacy. This is because ants relocated nests into and/or under these attractive nesting materials, thus increasing their exposure to toxic insecticide residues. Our results demonstrate efficacy of nonrepellent liquid insecticides as indoor treatments for the control of Pharaoh ants and possibly as exterior perimeter treatments.     

Can microbial-based insecticides replace chemical pesticides in agricultural production?

Extensive use of chemical insecticides to control insect pests in agriculture has improved yields and production of high-quality food products. However, chemical insecticides have been shown to be harmful also to beneficial insects and many other organisms like vertebrates. Thus, there is a need to replace those chemical insecticides by other control methods in order to protect the environment. Insect pest pathogens, like bacteria, viruses or fungi, are interesting alternatives for production of microbial-based insecticides to replace the use of chemical products in agriculture. Organic farming, which does not use chemical pesticides for pest control, relies on integrated pest management techniques and in the use of microbial-based insecticides for pest control. Microbial-based insecticides require precise formulation and extensive monitoring of insect pests, since they are highly specific for certain insect pests and in general are more effective for larval young instars. Here, we analyse the possibility of using microbial-based insecticides to replace chemical pesticides in agricultural production.     

Susceptibility to insecticides of Glyptapanteles militaris (Hymenoptera: Braconidae), a Parasitoid of Pseudaletia unipuncta (Lepidoptera: Noctuidae)

The susceptibility of cocoons and adults of Glyptapanteles militaris (Walsh) were studied. One organophosphate insecticide (trichlorfon), one organochlorine insecticide (endosulfan), one pyrethroid (deltamethrin) and a commercial formulation of Bacillus thuringiensis subsp. Kurstaki were selected for testing. All the tests were carried out with fresh solutions of commercial insecticides applied on host larvae at the recommended concentration. One- and 6-day-old cocoons were sprayed with the insecticide solutions by means of a Potter Tower and held for adult emergence. Adults were exposed to residues of insecticides inside plastic vials. The B. thuringiensis formulation had no harmful effect on the cocoons nor on the adults. Trichlorfon and endosulfan were highly toxic to all the tested stages. Deltamethrin was highly toxic to adults but relatively safe when applied on parasitoid cocoons. Based on these results, field applications of deltamethrin would be least disruptive of tested insecticides to populations of G. militaris.     

Hematological Disorders Following Exposure to Insecticides

The medical literature dealing with hematological disorders following exposure to insecticides (chiefly chlorinated hydrocarbons and organic phosphorus compounds) is briefly reviewed. The development of blood dyscrasias as a consequence of exposure to insecticides is considered unlikely. Reported cases are few in number and often involve persons with little contact with these materials. It is often impossible to prove (or to disprove) a cause-and-effect relation in the individual case. Pointers which may be of assistance in evaluating this relationship are described. Purpura as a result of allergic vascular changes after exposure to insecticides is also discussed.     

Susceptibility of pest Nezara viridula (Heteroptera: Pentatomidae) and parasitoid Trichopoda pennipes (Diptera: Tachinidae) to selected insecticides

Susceptibility of the southern green stink bug, Nezara viridula (L.) (Heteroptera: Pentatomidae), and its endoparasitoid Trichopoda pennipes (F.) (Diptera: Tachinidae) to acetamiprid, cyfluthrin, dicrotophos, indoxacarb, oxamyl, and thiamethoxam was compared in residual and oral toxicity tests. In the residual toxicity test, cyfluthrin, dicrotophos, and oxamyl were highly toxic to N. viridula. Thiamethoxam was moderately toxic to these insects. Each of the four insecticides was highly toxic to T. pennipes after prolonged tarsal contact with dried residues of these chemicals. In the oral toxicity test, where N. viridula fed on food covered with insecticide residues, none of the insecticides were toxic to adults of this stink bug, but acetamiprid, dicrotophos, and thiamethoxam were moderately toxic to the nymphs. In the oral toxicity test, where N. viridula fed on a gel-food containing insecticides, cyfluthrin, dicrotophos, oxamyl, and thiamethoxam were highly toxic to this stink bug. In an oral toxicity test using contaminated sugar water, all of the insecticides were highly toxic to T. pennipes. Because insecticides were as toxic, or more toxic, to T. pennipes than to N. viridula, it is extremely important to conserve this parasitoid by applying these insecticides for control of southern green stink bugs only when the pest reaches economic threshold.     

大型医院医疗设备采购流程精细化管理的探讨

医疗设备采购工作由于环节众多,过程复杂,且工作性质的特殊性、敏感性关系,很多的审批、监督环节无法省略,对工作速度造成了严重影响。该文探讨了一种基于项目团队模式的医疗设备采购管理新模式。打破了采购工作各相关部门的职能壁垒,按精细化管理的原则,构建了一个跨部门的医疗设备采购工作职能团队,快速、准确、高效地完成大型医院医疗设备购置工作,提高医疗设备采购工作的效率和质量,以充分发掘采购工作的效益。     

An investigation of the toxicity of insecticides to birds' eggs using the egg-injection technique

Twenty-five insecticides have been tested for their toxicity to hen embryos at various concentrations, using an egg-injection technique. Of the two major groups, the organophosphorus compounds are much more toxic than the organochlorine. Most organophosphorus compounds lower the hatch rate and cause teratogenic effects at 100 ppm. Most organochlorines do not harm the embryo at high dosages (up to 500 ppm), with notable exceptions to this among the cyclodienes. However, starvation of the hatched chicks suggests that the majority of organochlorine compounds can kill at this stage, though fed chicks survive. The solvent used affected toxicity; in general, insecticides are more toxic to the embryo when dissolved in corn oil than when dissolved in acetone. If these findings can be applied to wild birds, it can be assumed that the vast majority of insecticides are harmless to birds' eggs. They are either not toxic in the concentrations so far found in this country, or else unlikely to pass through the mother bird to the egg.     

德国医院临床运行模式浅析及其启示

德国奥格斯堡中心医院是一所综合性公立性医院,患者就诊能享受几乎全免费医疗服务,其眼科的运行方式,能够代表德国医疗体系的特点。医务人员具有高度的责任感,主动营造良好的医患沟通氛围。临床诊治严格遵循欧洲最新的眼科诊疗指南,询证医学证据。

     

Efficacy of several insecticides alone and with horticultural mineral oils on light brown apple moth (Lepidoptera: Tortricidae) eggs

The aim of the research was to identify efficacious and less environmentally harmful treatments than the standard chlorpyrifos sprays used for the control light brown apple moth, Epiphyas postvittana (Walker) (Lepidoptera: Tortricidae), eggs on nursery stock. A series of dip experiments showed a range of responses when comparing the efficacy of insecticides on egg hatch of E. postvittana. The insecticides that compared most favorably with chlorpyrifos were lamda-cyhalothrin and gamma-cyhalothrin, and thiacloprid. Indoxacarb, novaluron, and spinosad caused significant mortality only when combined with All Seasons mineral oil. All Seasons, showed ovicidal properties when evaluated alone and demonstrated adjuvant properties when combined with the above-mentioned insecticides, except gamma-cyhalothrin and thiacloprid. Several other horticultural mineral oils performed similarly, except the efficacy of spinosad varied with the oil product used, suggesting that the oil type selected is important for some insecticide and oil combinations. Several insecticides evaluated in this study are likely candidates for further work to develop treatments against E. postvittana eggs on nursery plants. Mineral oils are ovicidal and combinations with insecticides are likely to be advantageous.     

Transfer of ingested insecticides among cockroaches: effects of active ingredient, bait formulation, and assay procedures.

Foraging cockroaches ingest insecticide baits, translocate them, and can cause mortality in untreated cockroaches that contact the foragers or ingest their excretions. Translocation of eight ingested baits by adult male Blattella germanica (L.) was examined in relation to the type of the active ingredient, formulation, and foraging area. Ingested boric acid, chlorpyrifos, fipronil, and hydramethylnon that were excreted by adults in small dishes killed 100% of first instars within 10 d and >50% of second instars within 14 d. Residues from these ingested baits were also highly effective on nymphs in larger arenas and killed 16-100% of the adults. However, when the baits and dead cockroaches were removed from the large arenas and replaced with new cockroaches, only residues of the slow-acting hydramethylnon killed most of the nymphs and adults, whereas residues of fast acting insecticides (chlorpyrifos and fipronil) killed fewer nymphs and adults. Excretions from cockroaches that ingested abamectin baits failed to cause significant mortality in cockroaches that contacted the residues. These results suggest that hydramethylnon is highly effective in these assays because cockroaches that feed on the bait have ample time to return to their shelter and defecate insecticide-laden feces. The relatively high concentration of hydramethylnon in the bait (2.15%) and its apparent stability in the digestive tract and feces probably contribute to the efficacy of hydramethylnon. To control for differences among baits in inert ingredients and the amount of active ingredient, we compared 1% chlorpyrifos with 1% hydramethylnon in identical baits. Again, hydramethylnon residues provided greater secondary kill, but the results highlighted the importance of the inert ingredients. We conclude that, in the absence of cannibalism and necrophagy, translocation of baits and secondary kill are most effective with slow acting insecticides in palatable baits that can traverse the digestive tract and be deposited within and around the cockroach aggregation.     

The clinical psychologist; his role in private medical practice

The independent diagnosis and treatment of mental and nervous disorders according to California law constitutes practicing medicine. By this yardstick, an increasing number of clinical psychologists are entering the private practice of medicine. The medical profession has not provided through its leadership the opportunity for clinical psychologists to utilize their skills in a legitimate and supervised way in the treatment of private patients, nor has the medical profession taken sufficient interest in modern methods of treating patients with psychogenic disorders. If the psychiatric team is a feasible and practical approach to spreading the base of psychiatric treatment in hospitals and clinics, it should be applicable to private practice settings too. In the team setting, the psychologist can render great assistance to the physician in the diagnosis and treatment of patients with psychogenic disorders without compromising the principle that the primary responsibility for the patient is the physician's. By virtue of his training and experience, it is the psychiatrist who is best qualified to supervise the work of the psychologist; and until such time as the medical profession is better acquainted with psychotherapeutic techniques, the employment of psychologist assistants should be (according to good medical practice) left to the psychiatrist. The need for some regulation of the use of the title "psychologist" is increasing in order to protect the public from quacks who pose as psychologists. However, any law which is directed toward elimination of the quack should specifically define psychotherapy and contain provisions for its use under adequate medical supervision. The medical profession is obligated to take its traditional role in providing the best possible treatment for patients who are in need of it, and psychotherapy is an inherent part of treatment.     

Studies on the resistance to various insecticides of a house fly strain (Diptera: Muscidae) selected with azamethiphos.

A colony of azamethiphos-resistant house flies, Musca domestica (L.), was obtained from Denmark and further selected in the laboratory with azamethiphos for four generations. LD50s for various insecticides were determined and compared with those of a susceptible house fly strain. The selected flies showed cross-resistance to all insecticides evaluated. The flies were highly resistant to most organophosphorus, carbamate, and chlorinated hydrocarbon insecticides except prothiophos, p,p'-DDT, and the pyrethroids. We conclude that the main mechanisms responsible for resistance are presumed to be factors other than acetylcholinesterase sensitivity and nerve sensitivity due to knockdown resistance.     

Models for the structure and function of the Bacillus thuringiensis delta-endotoxins determined by compilational analysis

The protein delta-endotoxins of Bacillus thuringiensis are a commercially and environmentally important class of highly specific insecticides. From an alignment of their sequences, certain structural and functional domains can be inferred which may shed light on the mode of action of these toxins.     

Programmed Instruction: New Bottle for Rediscovered Wine

Programmed instruction is attracting attention at all educational levels. While this approach is new, the educational principles it incorporates are well established: instructional goals are defined in advance, the content is meticulously organized, active student participation is demanded, immediate feedback is provided to students, and each instructional unit is subjected to testing and revision. With its established effectiveness as a vehicle for introducing new topics, and for providing remedial and supplementary instruction, it can free the medical teacher to devote his time to matters which are more deserving of his attention, such as identifying and responding to individual student needs, exploring complex concepts, and working directly with students to provide a model and critical supervision. A more important potential contribution of programming may be that it has reminded us of sound educational precepts which deserve our attention in all forms of instruction.     

A Unique Teaching Experience: Medical Student Care of Northern Isolated Native Communities

To explore the benefits that students may derive from assuming responsibility for the medical care of people in isolated communities under a minimum of supervision, two volunteer third-year medical students spent the summer of 1964 caring for 1600 Indians and Metis at Wabasca, Alberta. They worked closely with the local public health nurse and a Catholic nursing sister who maintained a small hospital. Considerable experience was gained in preventive medicine and in the diagnosis and management of a wide variety of illnesses, using basic clinical skills and minimal laboratory facilities. The pressure of responsibility was particularly beneficial. It provided a potent impetus to learn and perfect skills in clinical medicine and basic therapeutics. Visits by an interested clinician every two to three weeks provided the optimum combination of responsibility and supervision. The existence of some local health organization was considered helpful.     

Modelling pest population resurgence due to recolonization of fields following an insecticide application

1. To investigate the effect of insect recolonization on the insecticide-induced resurgence of crop pests, a modified Lotka–Volterra predator–prey model was partitioned into two areas, 'sprayed' and 'unsprayed'.
2. The unsprayed area provided a source of insects to recolonize the sprayed area, resulting in a change in pest dynamics in both areas following an insecticide application.
3. Model sensitivity to insecticide selectivity and rates of predation, insect dispersal and pest population increase were examined.
4. Resurgence risk in the sprayed area increased with increasing pest dispersal rate, but decreased with increasing predator dispersal rate.
5. Pest resurgence could also occur in the unsprayed area, especially when prey dispersal rates were low. The extent of resurgence in the unsprayed area could in some circumstances be worse than in the sprayed area itself.
6. The more efficient and longer-lived the predators, the greater the level of pest resurgence in both areas following insecticide use.
7. More selective insecticides, killing the pest, but not the predator, reduced resurgence provided that the average life-span of the predators was reasonably long. Even highly selective insecticides could cause resurgence of the pest in the unsprayed area.
8. When the prey carrying capacity of the unsprayed area was increased relative to that of the sprayed area, resurgent effects in the unsprayed area were reduced, but could still be significant under some circumstances.