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41.
Polybrominated diphenyl ethers (PBDEs) are widely used as additive flame-retardants and have been detected in human blood,
adipose tissue, and breast milk. Developmental and long-term exposures to these chemicals may pose a human health risk, especially
to children. We have previously demonstrated that polychlorinated biphenyls (PCBs), which are structurally similar to PBDEs
and cause neurotoxicity, perturb intracellular signaling events including calcium homeostasis and protein kinase C translocation,
which are critical for neuronal function and development of the nervous system. The objective of the present study was to
test whether environmentally relevant PBDE congeners 47 and 99 are also capable of disrupting Ca2 + homeostasis. Calcium buffering was determined by measuring 45Ca2 + -uptake by microsomes and mitochondria, isolated from adult male rat brain (frontal cortex, cerebellum, hippocampus, and hypothalamus).
Results show that PBDEs 47 and 99 inhibit both microsomal and mitochondrial 45Ca2 + -uptake in a concentration-dependent manner. The effect of these congeners on 45Ca2 + -uptake is similar in all four brain regions though the hypothalamus seems to be slightly more sensitive. Among the two preparations,
the congeners inhibited 45Ca2 + -uptake in mitochondria to a greater extent than in microsomes. These results indicate that PBDE 47 and PBDE 99 congeners
perturb calcium signaling in rat brain in a manner similar to PCB congeners, suggesting a common mode of action of these persistent
organic pollutants.
The research described in this article has been reviewed by the National Health and Environmental Effects Research Laboratory
of the US Environmental Protection Agency, and approved for publication. Approval does not signify that the contents necessarily
reflect the views and policies of the Agency nor does mention of trade names or commercial products constitute endorsement
or recommendation for use.
These results will be presented at the 21th Biennial Meeting of International Society for Neurochemistry and American Society
for Neurochemistry in Cancun, Mexico (August 19–24, 2007).
Special issue article in honor of Dr. Frode Fonnum. 相似文献
42.
采用猪瘟病毒野毒珠(CSFV39)感染猪肾传代细胞系PK-15,经连续传79代,建立了稳定的病毒持续感染细胞模型,获得CSFV39-PK15细胞株。用免疫荧光、RT-PCR检测、透射电镜跟踪观察了CSFV39-PK15细胞株连续传代中病毒在细胞内的存在情况。结果表明第9,29,79代细胞仍有猪瘟病毒存在,表现出病毒持续感染的基本特征。这为深入研究猪瘟病毒持续感染机理奠定了基础。 相似文献
43.
Yuanxin Zhu Bridget Carragher David J. Kriegman Ronald A. Milligan Clinton S. Potter 《Journal of structural biology》2001,135(3):302-312
Since the foundation for the three-dimensional image reconstruction of helical objects from electron micrographs was laid more than 30 years ago, there have been sustained developments in specimen preparation, data acquisition, image analysis, and interpretation of results. However, the boxing of filaments in large numbers of images--one of the critical steps toward the reconstruction at high resolution--is still constrained by manual processing even though interactive interfaces have been built to aid the tedious and sometimes inaccurate boxing process. This article describes an accurate approach for automated detection of filamentous structures in low-contrast images acquired in defocus pairs using cryoelectron microscopy. The performance of the approach has been evaluated across various magnifications and at a series of defocus values using tobacco mosaic virus (TMV) preserved in vitreous ice as a test specimen. By integrating the proposed approach into our automated data acquisition and reconstruction system, we are now able to generate a three-dimensional map of TMV to approximately 10-A resolution within 24 h of inserting the specimen grid into the microscope. 相似文献
44.
45.
Marcus Baynes-Rock 《Anthrozo?s》2017,30(1):5-18
In this paper I review the literature on the evolutionary origins of phobias and describe the current state of research on the neurobiology and developmental origins of ophidiophobia—fear of snakes. In doing so I compare experimental evidence related to evolutionary explanations for snake fears and phobias which are outlined in Seligman’s Preparedness Theory and Isbell’s Snake Detection Theory. These theories have been tested extensively using a variety of experimental paradigms aimed at determining the “innateness” of snake fears, the neural pathways involved in fear responses to snakes, and the perceptual biases associated with snake stimuli. However, in the vast majority of these experiments, the stimuli presented are photographs of snakes rather than the real thing. I argue that this point of methodology, while ironically supportive of the findings, is based on some assumptions about cognition and consciousness which run counter to neuroscience. In understanding human responses to snakes, we need to understand better the interplay between cognition and consciousness and how these represent a pluralism of mind in which perception is much more than we think. 相似文献
46.
《Current biology : CB》2021,31(22):5093-5101.e5
Download : Download video (12MB) 相似文献
47.
《Biomarkers》2013,18(8):692-705
Greenlandic Inuit have high body burden of persistent organic pollutants (POPs). We analyzed the combined effect of the actual lipophilic serum POP mixture on estrogen-, androgen- and aryl hydrocarbon-receptor functions as effect biomarkers, and the associations between the effect biomarkers and serum POPs, and lifestyle characteristics. The serum POPs were extracted from 232 Inuit from Ittoqqortoormiit, Narsaq and Qeqertarsuaq. The POP-related receptor transactivities correlated negatively to the POP levels and were associated to the lifestyle characteristics. The POP-related receptor transactivities can be used as effect biomarkers. The serum POPs have hormone disruptive potentials. 相似文献
48.
49.
50.
This study examined the effects of attention on forming perceptual units by proximity grouping and by uniform connectedness
(UC). In Experiment 1 a row of three global letters defined by either proximity or UC was presented at the center of the visual
field. Participants were asked to identify the letter in the middle of stimulus arrays while ignoring the flankers. The stimulus
onset asynchrony (SOA) between stimulus arrays and masks varied between 180 and 500 ms. We found that responses to targets
defined by proximity grouping were slower than to those defined by UC at median SOAs but there were no differences at short
or long SOAs. Incongruent flankers slowed responses to targets and this flanker compatibility effect was larger for UC than
for proximity-defined flankers. Experiment 2 examined the effects of spatial precueing on discrimination responses to proximity-
and UC-defined targets. The advantage for targets defined by UC over targets defined by proximity grouping was greater at
uncued relative to cued locations. The results suggest that the advantage for UC over proximity grouping in forming perceptual
units is contingent on the stimuli not being fully attended, and that paying attention to the stimuli differentially benefits
proximity grouping. 相似文献