Effect of 3 organophosphates on the reproduction of Culex quinquefasciatus Say 1823

A 63-year-old woman was in hospital for persistent backache. Four months prior to admission she had been pointed out as having hypertension for the first time. On admission, she had anemia (hemoglobin 7.0 g/dl) with reticulocytosis, and a blood smear showed fragmented erythrocytes. A bone marrow aspirate disclosed erythroid hyperplasia and invasion of cancer cells. The chest roentgenogram showed a coin-lesion of the right lung and left pleural effusion. A diagnosis of microangiopathic hemolytic anemia (MAHA) associated with carcinomatosis was made, but the primary site of the cancer was unknown. Respiratory failure developed and the patient died a month later. Surprisingly, the autopsy revealed a malignant pheochromocytoma arising from the right adrenal gland with massive metastases to the lungs, liver, lymph nodes and systemic bones, and also disseminated intravascular coagulation (DIC). The DIC would probably account for the MAHA in this case. To our knowledge, this is the first reported case of malignant pheochromocytoma accompanied by MAHA.     

Effect of cypermethrin on some reproductive factors in Culex (C) quinquefasciatus Say 1823

An experiment was carried otu with a Culex quinquefasciatus strain with resistance genes called "Quibú", and with a susceptible strain provided by the WHO; they were pressured with different lethal doses of cypermetrine. Time-mortality regression lines of the 2 strains were estimated following WHO methodology and the "Quibú" strain showed tolerance to the insecticide. TL30 and TL70 were selected to test their effect on fecundity, fertility, sexual index, and egg eclosion time. A significant reduction in fecundity and fertility was observed in the "Quibú" strain after it was pressured, no effect was detected on the sexual index and egg eclosion time in this strain.     

Variation in organophosphate and carbamate insecticide resistance in relation to esterase activity in Culex (c.) quinquefasciatus Say, 1823 (Diptera: Culicidae)

We determined the existence of the resistance mechanism by means of the esterase enzymes in a Culex (C) quinquefasciatus stock established in the laboratory. Bioassays were performed with insecticides such as malathion and temephos (organophosphoric) and propoxur (carbomate); two cycles were completed during one year. Resistance to malathion was higher. The presence of esterase enzymes in this stock was determined by using synergits and starch gel and paper filter electrophoresis techniques.     

Seasonal variations of female aggressiveness and population dynamics of Culex quinquefasciatus Say 1823 in Abidjan (Republic of C?te d'Ivoire)

Seasonal variations of Culex quinquefasciatus aggressiveness were studied in Abidjan where this mosquito is very harmful. Abidjan is crossed from East to West by the Ebrié lagoon, which is a vast expanse of brackish water (about 566 km2). In the North of this expanse of water lay continental plateaux and in the South lay low-plateaux. The city is composed of 10 districts, most of which are situated on the continental plateaux. Culex quinquefasciatus adult populations were caught monthly in 1989 on human bait traps in Abidjan 10 districts, one study place was located in each district. Captures took place outside the houses, in the dusk and during the first part of night, that is to say between 4 p.m. and 1 a.m. In Abidjan, Culex quinquefasciatus population density varies considerably within the city area. In the areas where the species is numerous, a high percentage of it seems to be developing all year through from breeding places which are, in most cases, permanent. Besides, the aggressiveness seasonal cycle which was registered in the above mentioned areas is particularly diversified.     

The association of resistance to organophosphate, carbamate and pyrethroid insecticides with the mechanisms of resistance observed in Culex quinquefasciatus strains from Ciudad de La Habana province

The mechanisms of resistance in Culex quinquefasciatus from 6 municipalities of Havana City were studied in order to determine their genetic frequency. Increased esterases and altered acetylcholinesterase are still being the major resistance mechanisms in Havana City. The mechanisms of esterases is of high frequency, followed by altered acetylcholinestenase. Resistance to cholorpirifos was found for the first time in Culex quinquefasciatus, while resistance of malathion and carbamate propoxur is maintained, and deterioration to pyrethroid susceptibility is being detected. The synergistic effect of S.S.S. trubutyl phosphotritiade (DEF) and piperonil butoxide (PB) was analysed, and it was proven that esterases enzymes and multifunction oxidases are involved in the resistance to pyrethroids. By electrophoresis in polyerylamide gel, it was determined that the combination of esterases that seems to be associated with the resistance to perythroids is B1-A6-B6, which appeared with the greatest percentage. Valves of genetic frequency in the 6 municipalities were found to be high, for both esterase genes and acetylcholinesterase genes (Ache).     

Phospholipid composition of Culex quinquefasciatus and Culex tritaeniorhynchus cells in logarithmic and stationary growth phases

Culex quinquefasciatus and Culex tritaeniorhynchus cells were grown in spinner culture and harvested in logarithmic and stationary phases of growth. The phospholipids were extracted from the cells, and the fatty acid profiles of the phospholipid classes were determined and compared. The major components were phosphatidylcholine and phosphatidylethanolamine, constituting greater than or equal to 80% of the phospholipid. The fatty acid profiles of lysophosphatidylcholine, phosphatidylinositol, and cardiolipin showed changes with aging of the Culex cells and between the species. In the lysophosphatidylcholine fraction, there was an increase in saturation of the fatty acids of the C. quinquefasciatus cells, and chain lengthening occurred in both species from the logarithmic to stationary phases of growth. In the phosphatidylinositiol fraction, both Culex species showed a decrease in monoenes and an increase in polyenes, while only the C. tritaeniorhynchus cells showed an increase in fatty acid chain length with aging. The C. quinquefasciatus cells had an increase in polyenes with aging in the cardiolipin fraction. Differences in the percentage composition of the fatty acids were shown in all the phospholipid fractions between the Culex species in the logarithmic phase of growth and all except the phosphatidylinositiol and cardiolipin fractions in the stationary phase.     

Light-induced structural changes in cytochrome c oxidase: implication for the mechanism of electron and proton gating

We have investigated electrogenic events and absorbance changes following pulsed illumination of partly reduced cytochrome c oxidase in the absence of dioxygen and carbon monoxide (Hallén et al. (1993) FEBS Lett. 318, 134-138). In both types of experiment similar kinetics were observed; a rapid (tau < 0.5 micros) change was followed by relaxations with time constants of approx. 7 micros and 80 micros. Both the time constant and the activation energy of the 80 micros component were, within the experimental error, the same as those of one of the steps in the reduction of dioxygen by reduced cytochrome c oxidase. The absorbance changes showed a rapid haem reduction, followed by reoxidation. They were affected by CN(-) and N(-)3, ligands which bind in the binuclear centre of cytochrome c oxidase; the absorbance changes were quenched by CN(-) and in the presence of N(-)3, the amplitude of the 7 micros component increased whereas that of the 80 micros decreased. Based on these findings, a model is proposed which involves electron transfer from Cu(+)B to Fe(3+)A3, as a response to structural changes upon pulsed illumination. The same structural changes are also suggested to take place in the oxygen reduction. These changes may play an important role in the gating of electrons as well as protons, an obligatory feature of a redox-linked proton pump.     

WinCC工控组态软件在S7程序仿真调试中的应用

介绍了西门子公司的工控组态软件WinCC.该软件与PLCSIM仿真软件配合使用,可以实现S7-300与工控组态软件WinCC之间虚拟通讯,模拟控制过程.     

轧制带材的屈曲理论及其在冷轧机板形控制中的应用

本文首次应用薄板稳定理论求解了轧制带材各种复杂模态的在线屈曲临界域和瓢曲浪形成路径，成为正确的板形力学判据，它是在板形控制系统中建立控制目标设定模的理论基础，并在宝钢２０３０ｍｍ冷轧机中得以成功应用。     

Class restriction of cephalosporin use to control total cephalosporin resistance in nosocomial Klebsiella

CONTEXT: Resistance to most or all cephalosporin antibiotics in Klebsiella species has developed in many European and North American hospitals during the past 2 decades. OBJECTIVE: To determine if restriction of use of the cephalosporin class of antibiotics would reduce the incidence of patient infection or colonization by cephalosporin-resistant Klebsiella. DESIGN: A before-after comparative 2-year trial. SETTING: A 500-bed, university-affiliated community hospital in Queens, NY. PATIENTS: All adult medical and surgical hospital inpatients. INTERVENTION: A new antibiotic guideline excluded the use of cephalosporins except for pediatric infection, single-dose surgical prophylaxis, acute bacterial meningitis, spontaneous bacterial peritonitis, and outpatient gonococcal infection. All other cephalosporin use required prior approval by the infectious disease section. MAIN OUTCOME MEASURE: Incidence of patient infection or colonization by ceftazidime-resistant Klebsiella during 1995 (control period) compared with 1996 (intervention period). RESULTS: An 80.1% reduction in hospital-wide cephalosporin use occurred in 1996 compared with 1995. This was accompanied by a 44.0% reduction in the incidence of ceftazidime-resistant Klebsiella infection and colonization throughout the medical center (P<.01), a 70.9% reduction within all intensive care units (P<.001), and an 87.5% reduction within the surgical intensive care unit (P<.001). A concomitant 68.7% increase in the incidence of imipenem-resistant Pseudomonas aeruginosa occurred throughout the medical center (P<.01). All such isolates except one were susceptible to other antibiotics. CONCLUSION: Extensive cephalosporin class restriction significantly reduced nosocomial, plasmid-mediated, cephalosporin-resistant Klebsiella infection and colonization. This occurred at the price of increased imipenem resistance in P aeruginosa, which remained susceptible to other agents. Thus, an overall reduction in multiply-resistant pathogens was achieved within 1 year.     

Methicillin-resistant Staphylococcus aureus and its relationship to antimicrobial use: possible implications for control

The control of methicillin-resistant Staphylococcus aureus (MRSA) is still an unresolved issue in numerous healthcare institutions worldwide. Guidelines for the control of MRSA in hospitals focus on measures to control cross-transmission and prevent colonization, but rarely specifically mention the control of antimicrobial use. We reviewed the different types of evidence for a causal relationship between MRSA and antimicrobial use by classifying them in four categories: consistent associations, dose-effect relationships, concomitant variations, and arguments to support a plausible biological model to explain this relationship. Although the relative participation of cross-transmission and antimicrobial selection pressure in the level of MRSA observed in a healthcare setting remains to be determined, we found lines of evidence to support the existence of a relationship between MRSA and antimicrobial use in each of the four categories. This review points out the relative lack of studies specifically designed to investigate this aspect of MRSA epidemiology and the need to implement such studies quickly. In the meantime, the results presented here should encourage the implementation of antimicrobial-use improvement programs in hospitals in addition to existing infection control measures, which are still a priority in countries with high MRSA prevalence.     

环境和职业健康安全管理体系中的管理方案和运行控制的关系

对环境和职业健康安全管理体系中的管理方案和运行控制的关系的简单论述。     

高炉炉缸耐火材料抗渣侵蚀性及挂渣性

 对高炉炉缸用炭砖及刚玉砖的抗渣侵蚀性及挂渣性进行了研究。在1 500 ℃高温条件下进行试验,探究现场高炉渣对炭砖及刚玉砖的侵蚀机理,通过SEM-EDS及XRD等手段分析侵蚀界面的微观组织结构和物相组成,并提出炭砖及刚玉砖挂渣理论。试验结果表明,高炉渣与刚玉砖在侵蚀界面发生反应,反应生成的镁铝尖晶石及刚玉砖中的Al2O3、SiC等高熔点物质阻碍高炉渣对刚玉砖的进一步侵蚀;高炉渣在炭砖表面未生成高熔点物质,炭砖因与高炉渣黏结点少而导致高炉渣对炭砖黏结强度差,从而形成炭砖表面渣皮周期性脱落。     

Cloning of the ribosomal protein L41 gene of Phaffia rhodozyma and its use a drug resistance marker for transformation

The ribosomal protein L41 gene of Phaffia rhodozyma was cloned and used as a dominant selectable marker for cycloheximide resistance in the transformation of P. rhodozyma. Electrotransformation with a plasmid containing a ribosomal DNA fragment as a targeting signal typically yielded 800 to 1,200 transformants/microgram of DNA with an integrated copy number of about seven per haploid genome.     

Ways to correct disorders of the adaptation mechanism in patients with chronic calculous cholecystitis and concomitant atherosclerosis

Patients with chronic calculous cholecystitis presenting with atherosclerotic affliction of the heart reveal impairement of the mechanism of adaptation. A trigger mechanism in the activation of the hypophysial-adrenal system is, on the hand, a stressful impact on the frontal lobe of hypophysis and as a consequence of this a pain pang on the adrenal cortex accompanied by tissue hypoxia; on the other hand, disorders in the intrahepatic circulation of bile, enzymic disfunction of hepatocytes result, in their turn, in hypercholesterinemia which promotes augmentation of hydrocortisone levels. A quercetin-pectin complex has been proposed combined with SKN-type enterosorbent to correct the above disorders.     

A cognate tRNA specific conformational change in glutaminyl-tRNA synthetase and its implication for specificity

The placement of tissue expanders under the pectoralis major muscle has become a common procedure in breast reconstruction after mastectomy. Little information is available regarding the changes caused by tissue expansion on human skeletal muscle. In this study, we report the light and electron microscopic changes observed in 20 expanded pectoralis major muscles from 12 patients undergoing two-stage breast reconstruction procedures. Standard 400-cc round Radovan tissue expanders were placed, eight bilaterally and four unilaterally. Three biopsies were taken from each muscle at different locations during both the first stage (pre-expansion) and 23 weeks later at the second stage (postexpansion). The operative procedures and expansion protocol were the same in all reconstructions. No postoperative radiation therapy was added. The histologic changes were reported in a blind fashion by one pathologist. Light microscopy did not show significant pathologic changes. All but one of the pre-expansion specimens examined by electron microscope were reported as normal, whereas all of the postexpansion biopsies were grossly altered. Focal muscle fiber degeneration with glycogen deposits and mild interstitial fibrosis was noted. In addition, some fibers showed disorganization of the myofilaments in the sarcomeres. The above ultrastructural changes are significant morphologic alterations, which may be the result of muscle hypoxia. Whether these changes indicate permanent or transient transformation is yet unclear. Patient follow-up did not reveal any functional muscular deficit. We conclude that there is definite evidence to suggest significant muscular structural damage after routine subpectoral expansion for breast reconstruction.