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排序方式: 共有6132条查询结果,搜索用时 15 毫秒
61.
Li C Takahashi S Taneda S Furuta C Watanabe G Suzuki AK Taya K 《The Journal of reproduction and development》2007,53(3):673-678
In a previous study, we found that 3-methyl-4-nitrophenol (PNMC), a component of diesel exhaust particles and also a degradation product of the insecticide fenitrothion, exhibits reproductive toxicity in the adult male Japanese quail. The present study investigated the toxicity of PNMC in the female Japanese quail and its ability to influence reproduction in immature females. The quail (21-day-old) were injected intramuscularly (im) with PNMC at doses 0.1, 1 or 10 mg/kg body weight daily for 3 days. There was no significant difference in body growth between the PNMC-administered and control birds. However, the weights of the oviducts were significantly lower in the PNMC-treated birds at all doses. Furthermore, the plasma concentrations of luteinizing hormone (LH) and estradiol-17 beta were significantly decreased with 1 and 10 mg/kg of PNMC. These findings suggest that PNMC might influence the hypothalamo-pituitary-gonadal axis with decreasing in secretion of GnRH, LH and ovarian steroid hormones and subsequently disturb growth of the reproductive organs of immature female quail. This study indicates that PNMC induces reproductive toxicity at the central level and disrupts reproductive function in the immature female quail. 相似文献
62.
Jaroenporn S Nagaoka K Ohta R Watanabe G Taya K 《The Journal of reproduction and development》2007,53(4):887-893
Prolactin (PRL) has been proposed to directly stimulate corticosterone release. However, the role of PRL on adrenocortical function in male HAA rats has not been fully clarified. The aim of this study was to investigate the effect of PRL on the secretion of corticosterone and progesterone using an in vitro cell culture system in male rats. Administration of PRL (10(-7) and 10(-6) M) resulted in dose-dependent increases in corticosterone and progesterone release. Cotreatment with PRL produced an increase in the stimulatory effects of ACTH-induced corticosterone and progesterone secretion. However, the PRL-induced corticosterone and progesterone releases were significantly reduced by treatment with AG490, a specific Janus kinase 2 (Jak2) inhibitor. In addition, administration of AG490 blunted the significant inhibition of ACTH-induced corticosterone and progesterone secretion by PRL. These results demonstrated that PRL could act directly on the adrenal gland to drive corticosterone and progesterone secretion in male rats. Additionally, the results emphasize that PRL stimulation of adrenal steroid release may be mediated through Jak2 activity. 相似文献
63.
Assessment of fertility and reproductive toxicity in adult female mice after long-term exposure to Pueraria mirifica herb 总被引:1,自引:0,他引:1
Jaroenporn S Malaivijitnond S Wattanasirmkit K Watanabe G Taya K Cherdshewasart W 《The Journal of reproduction and development》2007,53(5):995-1005
The present study investigated the effects of long-term administration of Pueraria mirifica (PM) at non-toxic doses on the ovarian function and fertility of adult female mice based on evaluation of hematological and biochemical parameters. Female mice were divided into 4 groups (36 mice/group). Groups 1-3 were orally treated with a dose of 0 (PM-0), 10 (PM-10) or 100 mg/kg BW/day PM (PM-100), and group 4 was subcutaneously injected with 200 mug/kg BW/day of synthetic estrogen diethylstilbestrol (DES). The treatment schedule was separated into treatment and post-treatment periods. The duration of each period was 8 weeks. The PM-10 mice exhibited regular estrous cycles, while the PM-100 and DES treatments induced prolonged estrous cycles. Although no changes were observed in the uterus and ovary weights of the mice after the PM-100 and DES treatments, hyperplasia of the uterine endothelium and a decrease in the number of growing ovarian follicles were detected. The changes in the ovarian histologies of the PM-100 and DES mice were related to reductions in the levels of LH and FSH, which subsequently caused a decrease in mating efficiency. Once the PM mice were able to copulate, they were capable of successfully becoming pregnant and mothering offspring. No abnormalities were observed in the external morphologies and reproductive organ weights of the 50-day-old offspring. In conclusion, our results suggest that long-term exposure to 100 mg/kg BW of PM has adverse effects on the mating efficiency and reproduction of adult female mice and that administration of 10 mg/kg BW of PM does not induce any changes in the hypothalamic-pituitary-ovarian-uterine axis. 相似文献
64.
Effects of diesel exhaust particles on the male reproductive system in strains of mice with different aryl hydrocarbon receptor responsiveness 总被引:1,自引:0,他引:1
Izawa H Kohara M Watanabe G Taya K Sagai M 《The Journal of reproduction and development》2007,53(6):1191-1197
Diesel exhaust particles (DEPs) contain polycyclic aromatic hydrocarbons (PAH) that bind to aryl hydrocarbon receptors (AhRs) and decrease sperm production. Since it is not clear if AhR mediates DEP toxicity, we investigated the effect of DEPs in four strains of mice that have different AhR responsiveness. We treated BALB/c, C57BL/6, ICR and DBA/2 mice with DEP suspensions and compared their toxicity in each strain. In both the vehicle- and DEP-treated groups, ethoxyresorufin-O-deethylase (EROD) activity, as an indirect index of AhR activity, was increased in the order of BALB/c > C57BL/6 > ICR > DBA/2. Only BALB/c and C57BL/6 mice had significantly lower daily sperm production (DSP) than vehicle-treated mice. All strains exhibited increased sperm abnormalities. In particular, the C57BL/6, ICR and DBA/2 mice exhibited significantly increased abnormalities. A significant correlation was found between EROD activity and DSP or incidence of morphologically abnormal sperm. These data suggest that DEP toxicity may affect the male reproductive system in an AhR-dependent manner. 相似文献
65.
稻粉虱Aleurocybotus indicus David et Subramaniam, 属半翅目粉虱科, 以刺吸式口器为害水稻叶片而导致产量损失, 是我国闽?赣?浙等稻区的一种偶发性水稻害虫, 近20多年已鲜有报道, 但2019年-2021年在中国水稻研究所富阳试验农场稻田暴发?本文描述了稻粉虱的为害症状和形态特征, 并配以原色照片; 克隆得到了稻粉虱线粒体DNA COⅠ基因片段, 发现其与烟粉虱Bemisia tabaci序列一致性最高(85.80%); 田间调查表明, 富阳试验农场及周边稻田稻粉虱均有不同程度的发生, 但前者发生量明显较高(每个分蘖最高可达251头), 推测可能与农场温室内的稻粉虱越冬虫源有关; 利用稻苗浸渍法评估了不同作用机制的7种杀虫剂对稻粉虱的毒力, 发现双丙环虫酯?氯虫苯甲酰胺?氟啶虫胺腈?氟啶虫酰胺和溴氰虫酰胺对稻粉虱成虫均有较好的杀虫活性, 其中前4种药剂推荐中剂量处理后72 h的校正死亡率均可达100%, 其LC50分别为3.028?3.769?6.405 mg/L和7.894 mg/L?本研究可为我国稻粉虱的识别诊断和化学防治提供重要依据? 相似文献
66.
A dynamic mathematical model of the steam-cooled cyclone separator in a 440 t/h CFB boiler has been established.Based on the mathematical model,simulation model of the cyclone separator is created with the advanced continuous simulation language(ACSL).The validity of this model has been verified by the simulation experiments and analysis.This model can provide a theoretical guidance for operation and optimal design of the cyclone separator. 相似文献
67.
The electrocardiogram (ECG) signal is a recording of the electrical activity on the body surface generated by the heart frequency of which is weak and low. Many researchers devote themselves to get more perfect ECG in many ways. This article introduces the characterize of an ECG signal , then discusses the requirements for the sampling circuit of an ECG. Since there are some shortcoming in common design means, the authors give an effective circuit. The system is composed of a low-cost , low-power and high-performance MCU C8051F020 , amplifier AD620 , right-leg drive circuit ,communication circuit and power management circuit. Then software design is given which is used to sampling and filtering ECG signal. Levkov filter arithmetic and smooth filter arithmetics are used in this design. In the end , the authors advance a distributing and networking ECG monitor system. 相似文献
68.
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70.
基于DEM的水文模型在沮河流域的应用 总被引:2,自引:0,他引:2
基于DEM的流域水文模型是近年来水文模型的热点,而干旱半干旱地区的水文模型一直是水文研究的一个难题。分析了干旱地区的降雨产流特性,建立了符合该产流特性的数字高程模型和陕北模型相结合的水文模型,并将其应用到沮河流域桃曲坡水库的洪水预报中,计算结果证明该水文模型在干旱地区是切实可行的。 相似文献