Fasting reduces the incidence of vincristine‐associated adverse events in dogs

Fasting has been shown to decrease chemotherapy‐associated adverse events (AEs), in part through insulin‐like growth factor (IGF‐1) reduction, and may induce a protective effect on normal cells during chemotherapy treatment in mice and people. The purpose of this study was to evaluate the effect of fasting on constitutional, bone marrow and gastrointestinal (GI) AEs, and serum glucose, IGF‐1 and insulin levels in dogs receiving vincristine. The study was a prospective, crossover clinical trial in tumour‐bearing dogs. Dogs were randomized to be fasted for 24 to 28 hours prior to and 6 hours following their first or second vincristine treatment, and fed normally for the alternate dose. A significant reduction in nausea, anorexia, lethargy and serum insulin was observed when dogs were fasted; however, no significant differences were found in other GI symptoms, neutrophil count, serum glucose or IGF‐1. Fasting prior to vincristine therapy is a safe and effective treatment modality that helped mitigate constitutional and GI AEs in tumour‐bearing dogs.     

Metal Uptake in Plants and Health Risk Assessments in Metal‐Contaminated Smelter Soils

Metal pollution is an important concern because of its potential to affect human health. Metals such as lead and cadmium can enter soil via the food chain and exceed normal limits, producing harmful effects. In this study, six common garden and residential plant species were grown in soils from Spelter, WV, USA, contaminated with a variety of metals including lead (Pb), zinc (Zn), cadmium (Cd), and copper (Cu). Plant species included radish, carrot, chicory, spinach, lettuce, and clover. Metal concentrations in plant tissues were compared with metal concentration in soil by a multi‐step chemical extraction. The largest accumulation of Pb (126 mg kg⁻¹) and Zn (1493 mg kg⁻¹) was seen in radish roots, with Cd (40 mg kg⁻¹) having the largest accumulation in carrot roots. Comparisons of plant availability with soil chemical extractions indicated that the combined soluble and exchangeable fractions could estimate available Zn and Cd for all six plant species. For Pb and Cu, however, the comparisons indicate that these two elements were not readily available in Spelter soils. A health risk assessment was carried out for residents at Spelter on the basis of edible tissue concentrations and publicly available consumption data. Uptake of Cd by carrot roots was about five times more than the regulatory limits for men, eight times more for women, and 12 times more for children. On the basis of the results, carrot and lettuce grown in these soils have the potential to cause toxicological problems in men, women, and young children resulting from Cd and Zn accumulation. Copyright © 2013 John Wiley & Sons, Ltd.     

镉诱导的茶苗茎尖核酸代谢与细胞超微结构变化研究

试验研究茶苗经不同浓度Cd2 培养液培养12d结果表明,0 .0 5mmol/ L浓度Cd2 对茶苗相对生长量无明显影响,Cd2 浓度≥0 10mmol/ L时随处理浓度增加和时间延长,茶苗生长受抑程度逐渐加大。培养12d时0 0 5mmol/ L浓度Cd2 处理茶苗细胞内核糖体数量和核酸含量均高于对照,超过此浓度的处理其核糖体大量消亡,核酸含量显著降低,其中DNA含量变幅小于RNA。0 0 0～0 10mmol/ L浓度Cd2 处理RNase活性随浓度增加而升高,>0 2 5mmol/ L浓度Cd2 处理RNase活性则随浓度增加而降低。电镜观察结果表明轻度Cd2 毒害表现为核仁解体,染色质凝聚,核膜间隙扩大,核染色质进入核膜间隙,严重者出现核变形收缩,核膜破裂,核染色质扩散降解最终核解体     

水稻锰毒与铁素营养关系的研究

通过水培试验，研究了水稻锰毒与铁素营养关系，并探讨了过量锰对一些生理指标的影响。试验结果表明：地上部是生长介质中过量锰对水稻危害的主要部位；过量的锰增加铁在水稻根系的沉积，减少铁的吸收，改变体内铁的分布，降低铁的活性，诱发水稻缺铁胁迫；过量锰缺铁胁迫的水稻正常代谢受阻，叶片叶绿素、蛋白质含量减少，过氧化氢酶活性降低，而过氧化物酶活性增加     

土壤提取液中汽油的毒性研究

本文利用发光细菌法研究了土壤水提取液中2种汽油(90#和93#)的生物毒性。提取液中90#和93#汽油分别在63.2~90.1mg/L和62.7~91.1 mg/L范围内有较高的生物毒性,并随浓度的升高而增强,90#和93#汽油的土壤水提液EC50值分别为83.5 mg/L和83.7 mg/L,在土壤中的临界值为2308 mg/kg和3678 mg/kg。这些结果为发光细菌毒性测定方法在石油产品污染土壤生物毒性评价中应用提供了可能性。     

Membrane Dialysis Extraction (MDE): A Novel Approach for Extracting Toxicologically Relevant Hydrophobic Organic Compounds from Soils and Sediments for Assessment in Biotests

Goal, Scope and Background   Organic solvents are routinely used to extract toxicants from polluted soils and sediments prior to chemical analysis or bioassay. Conventional extraction methods often require the use of heated organic solvents, in some cases under high pressure. These conditions can result in loss of volatile compounds from the sample and the degradation of thermally labile target analytes. Moreover, extracts of soils and sediments also frequently contain substantial quantities of organic macromolecules which can act as sorbing phases for target analytes and in doing so interfere with both chemical analysis and bioassays. Membrane dialysis extraction (MDE) is described as a simple, passive extraction method for selectively extracting toxicologically relevant hydrophobic organic compounds (HOCs) from polluted soils and sediments and anaylzed for its applicability in ecotoxicological investigations. Methods   Toxicologically relevant hydrophobic organic compounds were extracted from wet and dry sediments by sealing replicate samples in individual lengths of pre-cleaned low-density polyethylene (LD-PE) tubing and then dialysing in n-hexane. The efficacy of the MDE method for use in ecotoxicological investigations was assessed by testing the concentrated extracts in the neutral red assay for acute cytotoxicity, in the EROD assay for the presence of dioxin-like compounds and in the Danio rerio fish egg assay for embryotoxic and teratogenic effects. Conditions of the sediment sample (with or without water content), dialysis membrane length and duration of dialysis were analyzed with respect to their impact on three endpoints. Results of the MDE investigations were compared to data obtained in samples prepared using conventional Soxhlet extraction. Results and Discussion   The membrane dialysis extraction was found to be at least as efficient as Soxhlet methodology to extract toxicologically relevant HOCs from sediment samples. In most cases, MDE-derived extracts showed a higher toxicological potential than the Soxhlet extracts. Lack of any significant effects in any MDE controls indicated these differences were not caused by contamination of the LD-PE membrane used. The elevated toxicological potential of MDE extracts is most likely the result of enhanced bioavailability of toxic compounds in consequence of lower amounts of organic macromolecules (i.e. sorbing phases) in the MDE extracts. This effect is probably the result of a size-selective restriction by the LD-PE membrane. Conclusion   Membrane dialysis extraction was found to be a simple, efficient and cost-effective method for the extraction of sediment samples. MDE can be used to extract toxicologically relevant hydrophobic organic compounds from both wet and dry sediments without the risk of loosing volatile and thermally labile target analytes. The size-selectivity of the LD-PE membrane also appears to have the capacity to increase the bioavailablity of potential target analytes in the resulting extracts by retaining much of the organic macromolecules present in the sample. Thus, results suggest that MDE may be particularly useful for the extraction of toxicologically relevant hydrophobic organic compounds from soils and sediments for bioassays and other ecotoxicological investigations. Recommendation and Perspective   Further validation of MDE has been initiated and the applicability of the methodology to other sample types will be investigated. Of particular interest is the potential application of MDE to recover hydrophobic target analytes from biological samples such as muscle, other soft tissues and blood.     

Aluminum inhibits apoplastic flow of high–molecular weight solutes in root apices of Zea mays L.

Using an aluminum (Al)‐sensitive maize cultivar, we investigated the influence of Al on the apoplastic solute bypass flow and its relationship with Al‐induced (1 h, 50 μM) callose formation and root growth. We selected the fluorescent probes 8‐hydroxypyrene‐1,3,6‐trisulfonic acid, trisodium salt (MW 524) (HPTS) and dextran‐Texas Red (TR) conjugates (MW 3,000, 10,000, and 40,000) to monitor their apoplastic transport. Confocal laser–scanning microscopy (CLSM) analysis and spectrofluorometric quantification showed Al‐induced callose formation in peripheral root cells within 1 h. Pretreatment of plants with the callose synthesis inhibitor 2‐deoxy‐D‐glucose (DDG) reduced the callose formation by half. Uptake experiments with both HPTS and dextrans showed uniform dye distribution in control root apices. After Al treatment for 1 or 2 h, which inhibited root growth by 32% or 50%, respectively, the dyes accumulated in the epidermal and outer cortical cell layers, especially in the 1–2 mm apical root zone. Al treatment reduced the export of the dyes out of the apical 1 cm treatment zone. This was due to strong sorption of HPTS but not of dextrans by Al‐loaded cell walls. Aluminum treatment reduced loading into the xylem sap particularly of higher–molecular weight dextrans. Pretreatment of roots with DDG and presence of 50 mM mannitol during the Al treatment partially forestalled the inhibitory effect of Al on the dye transport, but only slightly reduced the Al‐induced growth inhibition. Exudation experiments revealed that xylem water flow remained unaffected by the Al treatment of the root tips. The results with dextran suggest that Al binding in cell walls of the root apex inhibits apoplastic bypass flow of higher–molecular weight solutes, which might contribute to Al‐induced inhibition of root growth.     

Risks of Boron Toxicity in Canola and Lupin by Forms of Boron Application in Acid Sands of South-Western Australia

Boron (B) deficiency frequently occurs on soils that are low in organic carbon (C) (<1.0% organic C), pH (soil pH_Ca <5.0), and clay content (<5% clay). Acid sands with these soil properties are common in south-western Australia (SWA). Moreover, hot calcium chloride (CaCl₂) extractable B levels are commonly marginal in the acid sands of SWA. This study examined the effects of soluble and slow release soil-applied B fertilizer and foliar B sprays on crops most likely to respond to B fertilizer on these soils, canola (oil-seed rape, Brassica napus L.) and lupin (Lupinus angustifolius L.).

At 25 sites over three years, canola was grown with (0.34 kg ha-¹) or without B applied as borax [sodium tetraborate decahydrate (Na₂B₄O₇·10H₂O) 11% B], and this was followed by nine experiments with B rates [0, 0.55, 1.1 kg ha^?1, applied as borax or calcium borate (ulexite, NaCaB₅O₆(OH)₆·5(H₂O), 13% B] and foliar sprays (0.1% solution of solubor, 23% B) in 2000–2001. A further five sites of B rates and sources experiments were carried out with lupin in 2000–2001. Finally, foliar B sprays (5% B w/v as a phenolic complex) at flowering were tested on seven sites in farmers’ canola crops for seed yield increases. No seed yield increases to soil-applied B were found while foliar B application at flowering increased canola seed yield in only one season across seven locations. By contrast, borax fertilizer drilled with the seed at sowing decreased canola seed yield in nine of 34-farm sites, and decreased lupin yield in two of five trials. Toxicity from drilled boron fertilizer decreased yield could be explained by decreases in plant density (by 22–40%) to values lower than required for optimum seed yield. Seedling emergence was decreased by borax applied at sowing but less so by calcium borate. Foliar B spray application never reduced seed yield due to toxicity effects.

Boron fertilizer drilled with the seed increased the B concentration in plant dry matter at early to mid-flowering. Boron application decreased the oil concentration of grain of canola at four sites. The oil yield of canola was significantly decreased at seven sites.

Notwithstanding the marginal B levels on acid sands of the SWA region, care needs to be taken on use of borax fertilizer as toxicity was induced in canola and lupin; with 0.34 to 1 kg B ha^?1(3-10 kg borax ha^?1) at sowing depressing seed yield, mostly by decreasing plant density. Rather than making general recommendation for B fertilizer application based on 0.01M CaCl₂ soil extractable B, soil and plant analysis should be used to diagnose B deficiency and B fertilizer use limited to calcium borate or foliar borax rather than soil-applied borax on low B sands.     

杀毙灵对三种鱼苗急性毒性试验的初步探讨

在室内常温、静水条件下 ,采用换水生物试验法 ,以杀毙灵对巴西鲷、建鲤、白鲢三种鱼苗进行急性毒性试验。结果表明 :杀毙灵对巴西鲷、建鲤、白鲢的安全浓度 ( m L/m3)分别为 0 .0 0 2 6、0 .0 0 36、0 .0 0 4 4。96h鱼苗对杀毙灵的耐受能力为 :白鲢 >建鲤 >巴西鲷。     

农化措施降低污染土壤中锌对作物毒害性的研究

在锌污染蔬菜基地进行有机肥、钙镁磷肥、石灰等农化措施修复土壤生产能力的田间小区试验研究,结果表明:3种农化措施处理锌污染土壤后,能明显提高土壤上种植的冬春季、秋冬季蔬菜作物的产量,适当的农化措施联合处理可达到当地常规产量水平,与对照相比,生姜季增产15 38%～23 08%,莴苣季增产35 9%～82 5%;农化措施对夏秋高温季节种植的花生等对锌极敏感作物有延缓死亡、提高存活率的作用,但还不能达到作物正常生长、收获产量的目标。农化措施处理锌污染土壤,明显降低作物中锌含量,锌含量与作物产量呈反相关趋势。研究中发现,钙镁磷肥、石灰处理土壤后明显降低土壤有效锌含量,但有机肥施用后并不降低土壤有效锌含量,而作物锌含量却明显降低。