Effect of nutritional state on Hsp60 levels in the rotifer Brachionus plicatilis following toxicant exposure

The nutritional state of an organism can affect the results of toxicity testing. Here we exemplified this fact by examining the effect of nutritional deprivation on heat shock protein 60 (hsp60) production in the rotifer Brachionus plicatilis following exposure to two proven inducers of hsp60, a water-accommodated fraction of crude oil (WAF) and a dispersed oil preparation (DO). Both DO and WAF exposures of unfed rotifers resulted in significantly greater hsp60 levels than that of fed DO and WAF exposed rotifers at 8 h: 870 and 3100% of control, respectively. Results clearly demonstrate that a poor nutritional state potentiates stress protein induction upon exposure to water-soluble petroleum products. It is therefore critical to define the organismal nutritional status when reporting toxic responses.     

肤福牌皮肤消毒护肤喷雾剂的急性、亚急性毒性实验和刺激实验

目的：评价肤福牌皮肤消毒护肤喷雾剂的毒性和刺激性。方法：按照消毒技术规范（2002年版）进行急性和亚急性毒性实验、完整和破损皮肤刺激实验、急性眼刺激实验以及微核实验。结果：急性灌胃毒性实验结果显示,该产品对雌、雄小鼠的LD50〉5000mg／kg;对家兔多次完整皮肤、一次破损皮肤刺激实验,以及急性眼刺激实验均属无刺激性;500～5000mg／kg微核实验结果呈阴性;亚急性经口毒性实验,对雌、雄SD大鼠未观察到有害作用的剂量为1000mg／kg。结论：该产品属实际无毒级,无刺激性,安全性良好。     

Experimental studies on the effects of toxic Microcystis aeruginosa PCC7820 on the survival and reproduction of two freshwater rotifers Brachionus calyciflorus and Brachionus rubens

Blooms of Microcystis aeruginosa frequently occur in many eutrophic lakes in China, however, there is very little experimental study on the relationship between Microcystis and rotifers from Chinese waters. The effects of different concentrations of toxic M. aeruginosa PCC7820 on two common freshwater rotifers Brachionus calyciflorus and B. rubens were investigated in laboratory experiments. B. calyciflorus was able to utilize this strain of M. aeruginosa as a food source. However, M. aeruginosa suppressed the survival and reproduction of B. calyciflorus at the highest concentration (10⁶ cells/ml) probably due to the inadequate nutrition. B. rubens was inhibited by toxic M. aeruginosa PCC7820 and the inhibition increased with the increasing Microcystis concentration. Our study indicates that the two rotifers have different sensitivities to toxic M. aeruginosa and that toxic cyanobacteria may affect zooplankton community structure by differentially inhibiting the different zooplankton taxa.     

Acute toxicity of six metals to the Rotifer Brachionus calyciflorus,with comparisons to other freshwater organisms

There are several advantages to the use of planktonic rotifers as freshwater bioassay organisms, yet few studies report toxicological data for these taxa. The goal of the present study was to evaluate the 24-h acute toxicity responses of Brachionus calycifiorus to six heavy metals, and to compare metal tolerance of this species to published results for other aquatic organisms. Metal toxicity to B. calyciflorus, in decreasing order, was Hg > Cu > Cd > Zn > Fe > Mn. This order follows the theoretical ranking by affinity for anionic radicals based on Lewis acid-base classification. While not quite as sensitive as Daphnia magna, B. calyciflorus is potentially useful as a bioassay species because it is easy to culture and manipulate, and is widely distributed in alkaline waters of eastern North America.     

Ecological relevance and sensitivity depending on the exposure time for two biomarkers

Biomarkers are widely used to assess pesticide stress, but their ecological relevance and exposure time dependent sensitivity is still heavily debated. We studied both aspects in larvae of the damselfly Coenagrion puella, comparing the impact of low doses of atrazine, carbaryl, and endosulfan on two key biomarkers (acetylcholinesterase [AChE] activity and fluctuating asymmetry [FA]) and their relationship with life history traits (mortality, development time, growth rate, and body size). Larvae exposed to the pesticides had, in general, longer development times. Size, growth rate, and mortality were not affected by any of the pesticides. In the long-term exposure, AChE activity was diminished by atrazine treatments and stimulated by carbaryl treatments, and was not affected in the endosulfan treatments. FA decreased with increasing endosulfan concentrations and showed no reaction to atrazine or carbaryl. Overall, short-term exposure tended to overestimate the results of long-term exposure decreasing growth rates and enhancing inhibition of AChE activity in atrazine and carbaryl treatments. In line with its ecological relevance, relationship between biomarkers and life history traits showed that AChE inhibition was positively correlated with mortality, while FA was traded off with size. These results show that caution should be exerted when using these biomarkers to assess pesticide pollution in field situations.     

水痘带状疱疹病毒Oka株的培养特性和温度敏感性研究

目的  研究水痘带状疱疹病毒（varicella-herpes zoster virus,VZV）Oka株的培养特性及对温度的敏感性。方法  对VZV Oka株感染的2BS细胞进行培养,当2BS细胞的致细胞病变效应（cytopathic effect,CPE）达到10%时,开始收集0、3、6、9、12、18、24、36 h的病毒悬液并检测病毒滴度,观察病毒生长曲线。从VZV培养的第1天起,每天检测病毒蛋白浓度,连续检测7 d,观察病毒蛋白浓度变化。将3、12、24、36 h收集的病毒悬液分别于4 ℃和25 ℃放置0、3、6、9、12、24 h,并检测病毒滴度。结果  在2BS细胞的CPE达到10%后0~12 h和12~24 h,病毒生长分别进入对数期和平台期,随后进入衰亡期。在VZV培养过程中,病毒蛋白在经历2 d的初始期后,于2~6 d进入对数期,随后进入平台期。不同生长时期的病毒置于4 ℃的滴度下降幅度和速度都小于置于25 ℃。结论  VZV Oka株具有一般病毒的培养特性,并受温度影响较大。     

丙戊酸钠对幼鼠代谢的影响及肝毒性的试验探讨

目的：通过观察丙戊酸钠（VPA）作用后的Wistar幼鼠的肝功能、瘦素、胰岛素的变化分析对其影响因素。方法：选用SPF级3周龄雄性Wistar大鼠36只,平均体重48g。并随机分为两组（每组23只）,空白对照组：经口灌胃等量蒸馏水：VPA组：经口灌胃VPA300mg／（kg·d）,每周2次;3个月后检测体重变化、瘦素、胰岛素、血清A1月、血清AST、血清GST、肝MDA、肝GSH以及肝GST。结果：与空白对照组比较,VPA组AST、肝GST、瘦素、胰岛素显著升高（P〈0．01）,体重显著增加（P〈0．05）,肝GSH含量显著降低（P〈0．01）,而血清ASL、血清GST、肝MDA则均无统计学意义（P〉0．05）。结论：长期应用VPA会造成肝毒性及心血管系统潜在危险。     

血浆制备温度和时间对冷沉淀质量的影响

目的 探讨不同血浆制备温度和时间对冷沉淀质量的影响.方法 将新鲜冰冻血浆分成三个温度组通过虹吸法制备冷沉淀,比较融化时间和冷沉淀中FⅧ活性、Fg的含量.结果 2℃、4℃和6℃的融化时间分别为（96.3±5.9） min、（89.6±4.3） min、（81.2±2.7） min.温度越高,所需的融化时间越短.冷沉淀中FⅧ活性分别为（95.36±4.8）IU、（91.21±3.3）IU、（89.8±3.1）IU;冰冻血浆在2℃条件下融化所得冷沉淀中的FⅧ活性最高,与其他两组比较差异具有统计学意义（t=6.94,P=0.009,t =8.96,P=0.004）,但4℃和6℃条件下融化所得冷沉淀中FⅧ活性差异无统计学意义（t=0.669,P=0.19）.冷沉淀中Fg含量分别为（258.6±12.6）mg、（253.3±8.2）mg、（255.9±9.7） mg;不同血浆融化温度对Fg的含量没有显著影响,三组间两两比较差异无统计学意义（t=0.321,P=0.37;t =0.270,P=0.56;=0.424,P=0.29）.结论 2℃条件下血浆融化所制备的冷沉淀中FⅧ活性最高,但是所需时间也最长;6℃条件下融化血浆所制备的冷沉淀FⅧ活性较低,但是符合质量要求,而且所需时间最短,冷沉淀中Fg含量三个温度组之间没有区别.血站可以采用6 ℃融化冰冻新鲜血浆来制备冷沉淀.     

Influence of temperature and storage time after light exposure on the quinine monohydrochloride chemical actinometric system.

The ICH guideline on photostability has proposed quinine monohydrochloride chemical actinometric system as a standard method for measuring light exposure during photostability testing. A change in the absorption at 400 nm of quinine monohydrochloride after light exposure corresponds to a defined dose of light. The present work investigated the effect of temperature, light exposure level and the dark reactions following light exposure on the change of absorbance obtained. The change in the absorbance was linear with respect to time, the rate increased threefold in the temperature range of 25-52 degrees C, and the calculated activation energy was 30 kJ/mol as calculated by the Arrhenius equation. For the dark reactions the change in absorbance was non-linear with respect to time. The rate of the dark reactions was smaller than during light exposure and dependent on the light exposure level prior to the dark reactions. The calculated activation energy of the dark reactions was 18 kJ/mol when calculated by the Arrhenius equation on the initial reaction rates. The different activation energy of the light reaction and the dark reactions indicated different degradation patterns of the two reactions. The present study shows that the absorbance change of quinine monohydrochloride chemical actinometric system is dependent on temperature during light exposure and on storage time and storage temperature after light exposure. The method proposed in the ICH guideline should therefore be optimized in terms of definition of temperature and limitations in storage time after light exposure.     

Monitoring biodegradation of creosote in soils using radiolabels,toxicity tests,and chemical analysis

Microbial acclimation to, and mineralization of polycyclic aromatic hydrocarbons (PAHs), was studied using four uncontaminated soils (designated HS, HC, GP, MS) spiked with creosote and ¹⁴C‐phenanthrene. The effects of nutrient amendments (nitrogen and phosphorus), temperature (10°C and 22°C), and moisture content (50 or 85% of water‐holding capacity, WHC) on mineralization were monitored by measuring evolution of ¹⁴CO₂ in microcosms. Acclimation and mineralization occurred more rapidly at 22°C than at 10°C and were enhanced by the P amendment, at 50% of WHC for GP soil and 85% of WHC for HC and MS soils. These conditions were applied to microcosms containing 1500 g soil and monitored for biodegradation of total petroleum hydrocarbons (TPHs) and PAHs using chemical analysis and six soil toxicity tests. Although 40% ¹⁴C was recovered as CO₂ within 35–45 days in the smaller microcosms, analytical and toxicity test data indicated that bioremediation in the larger microcosms was not successful after 130 days. The soil depth and high moisture content may have restricted oxygen diffusion into the soil, which was not stirred during the experiment. Variations in toxicity and contaminant concentrations were observed but were considered a consequence of the sampling protocol and insufficient mixing during spiking, which may have produced pockets of “hot” soil. The mineralization experiment was useful for confirming that indigenous soil microorganisms could degrade PAHs, but was not indicative of the success of the bioremediation protocol on a larger scale. © 2000 John Wiley & Sons, Inc. Environ Toxicol 15: 99–106, 2000     

Aquatic toxicology of cypermethrin. I. Acute toxicity to some freshwater fish and invertebrates in laboratory tests

Cypermethrin is a synthetic pyrethroid. Its acute toxicity to ten freshwater invertebrates (Daphnia magna, Asellus aquaticus, Gammarus pulex, Cloeon dipterum, Gyrinus natator, Chironomus thummi, Aedes aegypti Cheoborus crystallinus, Corixa punctata, and Piona carnea) was determined in the laboratory using 24-h static water tests. The 24-h EC₅₀ values (based on reduced motility) ranged from 0.02 μg·l^?1for A. aquaticus and P. carnea to 2 μg·l^?1 for D. magna, and for seven of the species the EC₅₀ values were < 0.1 fig μg·l^?1 The 24-h LC₅₀values for G. natator, C. thummi, and C. punctata were > 5 μg·l^?1 For the seven more susceptible species the 24-h LC₅₀values ranged from 2 μg·l^?1 to 0.05 μg·l^?1The acute toxicity of cypermethrin to some species of fish (Cyprinus carpio. Scardinius erythrophthalmus, Salmo gairdneri, Salmo trutta and Tilapia nilotica) was determined using 96-h continuous-flow tests. The 96-h LC₅₀ values obtained were within the range 0.4–2.2 μg·l^?1.The solubility of cypermethrin within the range of test temperatures (15–25°C was estimated to be in the range 5–10 μg·l^?1.     

Analysis of pharmacokinetic data using parametric models. III. Hypothesis tests and confidence intervals

This is the third in a series of tutorial articles discussing the analysis of pharmacokinetic data using parametric models. In this article the concern is how to test hypotheses about, and assign confidence intervals to, the values of the parameters of such models. The basic approach to both tasks involves determining the goodness of fit of the model to the data for alternative values of the parameters and using the change in goodness of fit to assess the plausibility of the alternative values. The goodness of fit is measured by the value of a (least-squares-type) objective function. An approximation to the dependence of the latter on the parameter values yields an estimate of the familiar asymptotic covariance matrix of the estimates. The latter can also be used to test hypotheses about, and assign confidence intervals to, functions of parameters.Work supported in part by grants GM26676 and GM26691.     

Effects of subchronic exposures to concentrated ambient particles (CAPs) in mice. III. Acute and chronic effects of CAPs on heart rate, heart-rate fluctuation, and body temperature

Normal mice (C57) and mice prone to develop atherosclerosis (ApoE-/-) were implanted with electrocardiograph (EKG), core body temperature, and motion transmitters were exposed daily for 6 h to Tuxedo, NY, concentrated ambient particles (CAPs) for 5 day/wk during the spring and summer of 2003. The series of 5-min EKG monitoring and body-temperature measurements were obtained for each animal in the CAPs and filtered air sham exposure groups. Our hypothesis was that chronic exposure could cause cumulative health effects. We used our recently developed nonparametric method to estimate the daily time periods that mean heart rates (HR), body temperature, and physical activity differed significantly between the CAPs and sham exposed group. CAPs exposure most affected heart rate between 1:30 a.m. and 4:30 a.m. With the response variables being the average heart rate, body temperature, and physical activity, we adopted a two-stage modeling approach to obtain the estimates of chronic and acute effects on the changes of these three response variables. In the first stage, a time-varying model estimated daily crude effects. In the second stage, the true means of the estimated crude effects were modeled with a polynominal function of time for chronic effects, a linear term of daily CAPs exposure concentrations for acute effects, and a random component for unknown noise. A Bayesian framework combined these two stages. There were significant decreasing patterns of HR, body temperature, and physical activity for the ApoE-/- mice over the 5 mo of CAPs exposure, with smaller and nonsignificant changes for the C57 mice. The chronic effect changes of the three response variables for ApoE-/- mice were maximal in the last few weeks. There was also a significant relationship between CAPs exposure concentration and short-term changes of heart rate in ApoE-/- mice during exposure. Response variables were also defined for examining fluctuations of 5-min heart rates within long (i.e., 3-6 h) and short time periods (i.e., approximately 15 min). The results for the ApoE-/- mice showed that heart-rate fluctuation within the longer periods increased to 1.35-fold by the end of exposure experiment, while the heart-rate fluctuation within 15 min decreased to 0.7-fold.     

Toxicological characterisation of sludge from sewage treatment plants using toxicity identification evaluation protocols based on in vitro toxicity tests.

The ecotoxicological characterisation of complex mixtures, such as sludge from sewage treatment plants, is complex. Toxicity identification evaluation (TIE) protocols, developed by the United States Environmental Protection Agency (US EPA); to identify toxic pollutants in complex effluents, are useful tools in this context; to solve the difficulties in assessing unknown organic pollutants by analytical methods, the usefulness of bioassays to detect the relevant (toxic) organic compounds present in complex samples, and the possibilities of in vitro cytotoxicity tests as screening tools, offers a profitable combination. The sludge obtained from a sewage treatment plant was extracted by acetonitrile using a microwave extractor and fractionated in an HPLC system. The toxicity of every fraction was assayed using a RTG-2 cytotoxicty test, based on the fibroblastic RTG-2 fish cell line (ATCC, CCL N. 55). At exponential growth, three endpoints, beta-galactosidase activity, culture viability assayed by the neutral red assay (NR) and inhibition of growth rate using the FRAME KB protein assay (KBP), were used. By plotting the toxicity of each fraction vs elution time, the corresponding "toxicograms" were built. The UV and fluorescence chromatograms are compared to the three toxicograms (one for each toxicity endpoint).