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Opisthobranch molluscs of the family Onchidiacea have been reported to employ a chemical deterrent as a protection against predators. A single lipid-soluble compound, onchidal, has been isolated from the defensive secretion of Onchidella binneyi. The structure of onchidal was determined from spectral data and from chemical degradation studies. 相似文献
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Intranasal infection of mice by Vesicular Stomatitis Virus (VSV) often leads to breakdown of the blood-brain barrier (BBB). The role of Interleukin 12 (IL-12) and nitric oxide synthase (NOS) was examined here. Wild-type (WT), NOS-1 knockout (KO), and NOS-3 KO mice were infected with VSV and treated with either IL-12 or medium. IL-12 treatment of uninfected hosts did not result in pathology. In contrast with WT and NOS-1 KO mice, where extensive gross and ultrastructural correlation of BBB breakdown were evident following infection, in NOS-3 KO mice, integrity of the BBB was observed. Thus NOS-3 activity in astrocytes, endothelial cells, or ependymal cells may play an essential role in regulating the BBB. 相似文献
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Alicia L. Carriquiry William P. Ireland Wolfgang Kliemann Etsuro Uemura 《Bulletin of mathematical biology》1991,53(4):579-589
A mathematical model (Kliemann, W. 1987.Bull. math. Biol.
49, 135–152.) that predicts the quantitative branching pattern of dendritic tree was evaluated using the apical and basal dendrites
of rat hippocampal neurons. The Wald statistics for χ2-test was developed for the branching pattern of dendritic trees and for the distribution of the maximal order of the tree.
Using this statistic, we obtained a reasonable, but not excellent, fit of the mathematical model for the dendritic data. The
model's predictability of branching patterns was greatly enhanced by replacing one of the assumptions used for the original
model “splitting of branches for all dendritic orders is stochastically independent”, with a new assumption “branches are
more likely to split in areas where there is already a high density of branches”. The modified model delivered an excellent
fit for basal dendrites and for the apical dendrites of hippocampal neurons from young rats (30–34 days postpartum). This
indicates that for these cells the development of dendritic patterns is the result of a purely random and a systematic component,
where the latter one depends on the density of dendritic branches in the brain area considered. For apical dendrites there
is a trend towards decreasing pattern predictability with increasing age. This appears to reflect the late arrival of afferents
and subsequent synaptogenesis proximal on the apical dendritic tree of hippocampal neurons. 相似文献
630.
C. M. Ireland H. T. A. Cheung A. J. Ryan G. M. Holder 《Chemico-biological interactions》1982,40(3):305-318
The metabolism of the weak carcinogen 7-methylbenz[c]acridine (7MBAC) was examined in rat liver microsomes from 3-methylcholanthrene(MC)-induced animals by the use of mixed 14C- and 2H-labelled substrate. The three metabolites identified by spectroscopic and chromatographic examination were 7-OHMBAC and two dihydrodiols. The dihydrodiols were assigned structures consistent with attack on the 8,9- and 5,6- or K-region of the aromatic system. 相似文献