No effect of exogenous melatonin on development of cryopreserved metaphase II oocytes in mouse

Background

This study was conducted to investigate effect of exogenous melatonin on the development of mouse mature oocytes after cryopreservation.

Results

First, mouse metaphase II (MII) oocytes were vitrified in the open-pulled straws (OPS). After warming, they were cultured for 1 h in M₂ medium containing melatonin at different concentrations (0, 10⁻⁹, 10⁻⁷, 10⁻⁵, 10⁻³ mol/L). Then the oocytes were used to detect reactive oxygen species (ROS) and glutathione (GSH) levels (fluorescence microscopy), and the developmental potential after parthenogenetic activation. The experimental results showed that the ROS level and cleavage rate in 10⁻³ mol/L melatonin group was significantly lower than that in melatonin-free group (control). The GSH levels and blastocyst rates in all melatonin-treated groups were similar to that in control. Based on the above results, we detected the expression of gene Hsp90aa1, Hsf1, Hspa1b, Nrf2 and Bcl-x1 with qRT-PCR in oocytes treated with 10⁻⁷, or 10⁻³ mol/L melatonin and untreated control. After warming and culture for 1 h, the oocytes showed higher Hsp90aa1 expression in 10⁻⁷ mol/L melatonin-treated group than in the control (P < 0.05); the Hsf1, Hsp90aa1 and Bcl-x1 expression were significantly decreased in 10⁻³ mol/L melatonin-treated group when compared to the control. Based on the above results and previous research, we detected the development of vitrified-warmed oocytes treated with either 10⁻⁷ or 0 mol/L melatonin by in vitro fertilization. No difference was observed between them.

Conclusions

Our results indicate that the supplementation of melatonin (10⁻⁹ to 10⁻³ mol/L) in culture medium and incubation for 1 h did not improve the subsequent developmental potential of vitrified-warmed mouse MII oocytes, even if there were alteration in gene expression.     

Subcutaneous administration of paclitaxel in dogs with cancer: A preliminary study

Intravenous paclitaxel has been underused in dogs due to severe and acute hypersensitivity reactions. Subcutaneous (SC) administration of paclitaxel and its safety are unknown. In this preliminary study, SC administration of paclitaxel was evaluated for hypersensitivity reactions and toxicity in 21 dogs with advanced cancer. Dogs received 1 to 5 paclitaxel doses, ranging from 85 to 170 mg/m², SC every 14 or 21 days. A total of 40 paclitaxel doses were administered and none of the 21 dogs developed systemic or acute local hypersensitivity reactions. Severe skin lesions at the injection site developed in 2 dogs after the 4th injection at the same location. Grade 4 neutropenia was observed in 50% of the dogs 5 days after the first treatment at 115 mg/m² (n = 14). Two animals developed Grade 5 diarrhea and died likely due to hemodynamic failure or sepsis. Paclitaxel can be administered SC in dogs with no hypersensitivity reaction.     

右美托咪定抑制NOX4缓解急性应激致大鼠肾损伤

本研究拟探索右美托咪定（dexmedetomidine,DEX）对大鼠急性应激致肾损伤的保护作用,并从氧化应激的角度探索DEX对大鼠肾的保护通路。本研究使用了急性束缚应激模型,其中,大鼠被迫游泳15 min,并束缚3 h。本试验采用生化检测、组织病理学切片观察以评估肾功能,然后测定了氧化应激以及氧化应激的相关通路蛋白。旷场试验证实成功建立了急性应激模型。急性应激引起的肾损伤增加了NOX4,降低了Nrf2/HO-1/NQO1表达水平。DEX可降低NOX4表达,同时升高Nrf2/HO-1/NQO1的表达水平。DEX治疗组与急性应激组相比的肾生化结果明显恢复正常,病理切片观察损伤显著降低。试验结果表明,DEX治疗急性应激可影响NOX4/Nrf2/HO-1/NQO1信号通路,并抑制氧化应激。因此,DEX对急性应激引起的肾损伤具有保护作用,并在应激综合征中具有潜在的临床应用。     

短花针茅荒漠草原物种间关系的多度不对称性对载畜率的响应

目前物种的相对多度与种间关系的内部联系如何影响物种共存仍不清楚。为探讨植物群落物种间关系强度的多度不对称性及其对载畜率的响应,本研究以内蒙古短花针茅(Stipa breviflora)荒漠草原植物群落为对象,分析了对照、轻度、中度及重度放牧下群落物种的多度及其频率。结果表明：随载畜率的增大,物种数呈现出降低的趋势。不同载畜率下同分布指数CO均存在明显的多度依赖性;常见种(如短花针茅、无芒隐子草(Cleistogenes songorica)及刺穗藜(Chenopodum aristatum))对其他物种的作用强度普遍较强。不同载畜率下短花针茅对无芒隐子草及刺穗藜的作用强度均高于其二者对短花针茅的强度,表现出种间强度的不对称性。此外,放牧使得短花针茅对无芒隐子草的作用强度呈现出增大的趋势,使得无芒隐子草对短花针茅的作用强度呈现出降低的趋势。因此,物种间存在多度的不对称性,而放牧进一步造成其物种间作用强度的变化。     

森林工程装备底盘研究综述

随着我国林业的发展和劳动力日益紧张,森林工程作业机械化的重要性更加凸显。在我国山地、丘陵地区,森林工程装备底盘的性能决定了森林工程装备能否"上山入林",影响森林工程机械化的进程。本文对近些年国内外装备底盘上的研究成果进行介绍,包括具有较强越野能力的装备底盘以及有助于改善底盘性能的关键机构(悬架、转向、车轮),分析各自的优缺点,基于我国典型林区立地条件的基础上提出适合我国山地、丘陵地区作业的森林工程装备底盘的性能要求。     

平潭主岛陆相区域景观格局动态变化分析

运用景观生态学的理论和方法,以平潭综合实验区主岛陆相区域为研究对象,利用1996年、2002年、2008年3个时相遥感影像为主要数据源,分析了与防护林关系密切的土地利用类型的景观格局指数,以期为平潭防护林乃至区域生态建设提供参考依据。结果表明:研究区景观格局呈现进一步破碎的趋势,与平潭经济社会发展的趋势一致;建筑用地、农用地等与林地关系密切的土地利用方式各项景观格局指数变化较强烈。最后从维护海岛生态安全的角度提出了4点建议。     

内廊式建筑热压诱导通风模式的研究

指出了基于热压通风原理的被动式诱导通风是一种有效的绿色建筑节能策略,分析了常规热压通风应用模式及存在的问题,在此基础上,针对内廊式建筑的特征及气候适用性,提出了一种具有生态效能的热压诱导自然通风模式,探讨了该通风模式的工作原理、应用特性,并说明了其节能设计上的可行性.此结果为深入研究和应用热压自然通风新技术提供一定的思路.     

浅谈移动通信宏基站的环保管理

通过理论计算的方式,对移动通信宏基站所使用的设备是否需要进行环保管理进行了说明.同时,利用绍兴地区电磁环境监测现状监测数据,计算了移动通信宏基站正常运行时所产生的电磁辐射量,并根据现状监测结果,对照相关电磁辐射防护标准,探讨了移动宏通信基站在正常工况下是否可以满足现有的国家标准.     

西伯利亚白刺优良无性系嫩枝扦插技术试验

采用自动喷雾扦插育苗设备,对双岗01、双岗02、双岗03、双岗04四个白刺优良无性系用正交设计进行嫩枝扦插试验,结果表明:白刺无性系间生根率及生根数有极显著差异,对主根长没有影响;植物调节剂的种类及浓度和处理时间对生根率有显著影响,但对生根数及主根长没有影响。其中双岗04的生根效果最好,其最佳生根组合为250 mg.kg-1的生根粉处理2 h。