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排序方式: 共有64条查询结果,搜索用时 15 毫秒
1.
EA Dukhanina TI Lukyanova EA Romanova V Guerriero NV Gnuchev GP Georgiev DV Yashin LP Sashchenko 《Cell cycle (Georgetown, Tex.)》2015,14(22):3635-3643
PGRP-S (Tag7) is an innate immunity protein involved in the antimicrobial defense systems, both in insects and in mammals. We have previously shown that Tag7 specifically interacts with several proteins, including Hsp70 and the calcium binding protein S100A4 (Mts1), providing a number of novel cellular functions. Here we show that Tag7–Mts1 complex causes chemotactic migration of lymphocytes, with NK cells being a preferred target. Cells of either innate immunity (neutrophils and monocytes) or acquired immunity (CD4+ and CD8+ lymphocytes) can produce this complex, which confirms the close connection between components of the 2 branches of immune response. 相似文献
2.
Plasminogen activator and collagenase production by cultured capillary endothelial cells 总被引:33,自引:17,他引:16 下载免费PDF全文
Cultured bovine capillary endothelial (BCE) cells produce low levels of collagenolytic activity and significant amounts of the serine protease plasminogen activator (PA). When grown in the presence of nanomolar quantities of the tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA), BCE cells produced 5-15 times more collagenolytic activity and 2-10 times more PA than untreated cells. The enhanced production of these enzymes was dependent on the dose of TPA used, with maximal response at 10(-7) to 10(-8) M. Phorbol didecanoate (PDD), an analog of TPA which is an active tumor promoter, also increased protease production. 4-O-methyl-TPA and 4α-PDD, two analogs of TPA which are inactive as tumor promoters, had no effect on protease production. Increased PA and collagenase activities were detected within 7.5 and 19 h, respectively, after the addition of TPA. The TPA-stimulated BCE cells synthesized a urokinase-type PA and a typical vertebrate collagenase. BCE cells were compared with bovine aortic endothelial (BAE) cells and bovine embryonic skin (BES) fibroblasts with respect to their production of protease in response to TPA. Under normal growth conditions, low levels of collagenolyic activity were detected in the culture fluids from BCE, BAE, and BES cells. BCE cells produced 5-13 times the basal levels of collagenolytic activity in response to TPA, whereas BAE cells and BES fibroblasts showed a minimal response to TPA. Both BCE and BAE cells exhibited relatively high basal levels of PA, the production of which was stimulated approximately threefold by the addition of TPA. The observation that BCE cells and not BAE cells produced high levels of both PA and collagenase activities in response to TPA demonstrates a significant difference between these two types of endothelial cells and suggests that the enhanced detectable activities are a property unique to bovine capillary and microvessel and endothelial cells. 相似文献
3.
Separation of dissociated thyroid follicular and parfollicular cells: association of serotonin binding protein with parafollicular cells 下载免费PDF全文
Parafollicular cells (PC) of the sheep thyroid gland are neural crest derivatives that synthesize and release the biogenic amine serotonin (5-HT) as well as the hormone calcitonin. The thyroid also contains a highly specific serotonin-binding protein (SBP). Separation of dissociated thyroid cells was done to study the cellular localization of SBP and to develop a means of isolating PC for study. Various methods were used to obtain an enriched and purified population of PC. Minced thyroid glands were enzymatically dissociated and the cells were layered on a Ficoll linear density gradient. Fractions obtained from the gradient were examined for cell number, viability, 5-HT concentration, SBP activity, and morphology by electron microscopy. One of the fractions was found to be enriched in PC. High levels of 5-HT and SBP were also found in this fraction, whereas these levels were low where the majority of cells were found. This PC-rich fraction, however, contained numerous follicular cells (FC); therefore, additional approaches to cell separation were used. FC can be stimulated in vitro with thyroid stimulating hormone (TSH) to become intensely phagocytic. When stimulated cells were incubated in the presence of silica microspheres, the FC engulfed the microspheres, which were toxic to them. PC did not become phagocytic and were unharmed by the microspheres. Suspended cells, after incubation with microspheres, were centrifuged on a discontinuous gradient, and a PC-rich fraction was obtained. Silica, however, interfered with analysis of SBP. Another method to take advantage of the phagocytic potential of FC was therefore used. TSH-stimulated cell suspensions were passed through a column of sepharose to which thyroglobulin had been coupled. Stimulated FC apparently adhered to the beads and were retained by the columns. Fractions eluting from the columns were greatly enriched with PC. These fractions contained high levels of 5-HT and SBP, and considerably reduced FC contamination was found by quantitative electron microscopy. It is concluded that SBP is localized to PC in the sheep thyroid. The idea that these cells resemble serotonergic neurons in their mechanisms of 5-HT storage is supported. 相似文献
4.
Isaac Okyere Juliet Afrah Obeng Samuel Ayitey Jouke Rients Van der Zee Herman Meeus 《Journal of fish biology》2021,99(2):411-417
Aside from ornamental uses, there is growing interest in using killifishes for a multiplicity of purposes including baitfish and mosquito biocontrol. This experiment explored the spawning habits and embryonic development of the banded lampeye, Aplocheilichthys spilauchen in ex situ freshwater (0.04‰) and brackish water (5.01‰) to ascertain the captive breeding prospects for mosquito control in areas where they occur. Significantly higher number of eggs were laid in the brackish water than the freshwater (X2 = 1613.0, P < 0.05), and black mop was the most preferred spawning substrate, followed by green, blue and white mops. Microscopic monitoring of embryos revealed that cleavage occurred within the first 30 min after fertilization, organogenesis commenced on average in the 25th hour and hatching in approximately 230 h. Although freshwater eggs were relatively bigger than brackish water eggs and certain embryonic developmental stages occurred faster in the freshwater than brackish water, these differences were overall not significant and had no effects on the development and hatching. The observed outcome that A. spilauchen can be optimally propagated with black mops in brackish water offers a significant step in its use for the mosquito biocontrol programme, as well as other potential uses not yet explored. 相似文献
5.
In a three-hour bioassay, we tested the palatability and feeding preferences of Uresiphita maorialis (kōwhai moth) for Sophora tetraptera, Sophora microphylla and Sophora prostrata. Palatability tests showed no differences among the Sophora species. Feeding preferences, on the other hand, showed that S. tetraptera and S. microphylla leaves are preferred over S. prostrata leaves. Our results support our field observations in Wellington city parks and gardens showing that S. tetraptera and S. microphylla plants frequently have higher densities of larvae than S. prostrata. 相似文献
6.
Jolanda?HM?van Bilsen Josée?PA?Wagenaar-Hilbers Maarten?JF?van der Cammen Mariska?EA?van Dijk Willem?van Eden Marca?HM?WaubenEmail author 《Arthritis research & therapy》2002,4(4):R2
We have recently found that matrix metalloproteinases (MMPs) are targets for T-cell and B-cell reactivity in experimental
arthritis. In the present article, we investigate whether modulation of MMP-specific T-cell responses could influence the
course of adjuvant arthritis (AA). Lewis rats were treated nasally with MMP peptides prior to or after AA induction. Administration
of the MMP-10 or the MMP-16 peptide prior to AA induction reduced the arthritic symptoms. In contrast, administration of the
MMP-10 peptide after AA induction aggravated the arthritic symptoms. The present study shows the possible usefulness of MMP
peptides for immunotherapy. However, a clear understanding of proper timing of peptide administration is crucial for the development
of such therapies. 相似文献
7.
Effects of medium viscosity on kinetic parameters of poly(U) hydrolysis catalyzed by RNase from Bac. intermedius 7P (binase) were studied in solutions of sucrose (4-50 wt. %) and glycerol (35-62 wt. %) in Tris--sodium acetate buffer (pH 7.5) at 25 degreesC. The rate constant of reaction kcat was practically unchanged over a wide range of viscosities (1-15 cP for sucrose and 2.5-3 cP for glycerol). In glycerol solutions, kcat slightly increased with viscosity increase from 4 to 10 cP. Addition of NaCl to the buffer medium resulted in an inhibitory effect of Na+ on kcat, prevented by 50% sucrose or 60% glycerol. It is concluded that binase-catalyzed poly(U) cleavage occurs through a "tense"-substrate mechanism, similarly to reactions catalyzed by alpha-chymotrypsin, trypsin, and laccase. 相似文献
8.
Interest in the use of low-copy nuclear genes for phylogenetic analyses of
plants has grown rapidly, because highly repetitive genes such as those
commonly used are limited in number. Furthermore, because low- copy genes
are subject to different evolutionary processes than are plastid genes or
highly repetitive nuclear markers, they provide a valuable source of
independent phylogenetic evidence. The gene for granule-bound starch
synthase (GBSSI or waxy) exists in a single copy in nearly all plants
examined so far. Our study of GBSSI had three parts: (1) Amino acid
sequences were compared across a broad taxonomic range, including grasses,
four dicotyledons, and the microbial homologs of GBSSI. Inferred structural
information was used to aid in the alignment of these very divergent
sequences. The informed alignments highlight amino acids that are conserved
across all sequences, and demonstrate that structural motifs can be highly
conserved in spite of marked divergence in amino acid sequence. (2)
Maximum-likelihood (ML) analyses were used to examine exon sequence
evolution throughout grasses. Differences in probabilities among
substitution types and marked among-site rate variation contributed to the
observed pattern of variation. Of the parameters examined in our set of
likelihood models, the inclusion of among-site rate variation following a
gamma distribution caused the greatest improvement in likelihood score. (3)
We performed cladistic parsimony analyses of GBSSI sequences throughout
grasses, within tribes, and within genera to examine the phylogenetic
utility of the gene. Introns provide useful information among very closely
related species, but quickly become difficult to align among more divergent
taxa. Exons are variable enough to provide extensive resolution within the
family, but with low bootstrap support. The combined results of amino acid
sequence comparisons, maximum-likelihood analyses, and phylogenetic studies
underscore factors that might affect phylogenetic reconstruction. In this
case, accommodation of the variable rate of evolution among sites might be
the first step in maximizing the phylogenetic utility of GBSSI.
相似文献
9.
Although studies have examined religious differences in fertility in sub-Saharan Africa, it is argued in this paper that using women-only sample data may be conceptually problematic in patriarchal African societies where the influence of husbands on their wives' reproductive preferences is paramount. The present study contributes to this discourse by examining the relationship between religion and fertility behaviour using matched-couple data from Ghana. Guided by the 'religious values' and 'characteristics' hypotheses, the results indicate significant religious differences in fertility. Compared with Traditionalists, Christians and Muslims have lower fertility, albeit these differences diminish significantly after controlling for socioeconomic variables. The impact of wife's religious denomination on marital fertility is attenuated after controlling for husband's religious affiliation. Also, fertility was found to be higher if couples belong to the same faith compared with those of different faiths. 相似文献
10.
Bindi Dangi Marcus Obeng Julie M. Nauroth Mah Teymourlouei Micah Needham Krishna Raman Linda M. Arterburn 《The Journal of biological chemistry》2009,284(22):14744-14759
Enzymatically oxygenated derivatives of the ω-3 fatty acids
cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) and
cis-5,8,11,14,17-eicosapentaenoic acid, known as resolvins, have
potent inflammation resolution activity (Serhan, C. N., Clish, C. B., Brannon,
J., Colgan, S. P., Chiang, N., and Gronert, K. (2000) J. Exp. Med.
192, 1197–1204; Hong, S., Gronert, K., Devchand, P. R., Moussignac, R.,
and Serhan, C. N. (2003) J. Biol. Chem. 278,
14677–14687). Our objective was to determine whether similar derivatives
are enzymatically synthesized from other C-22 fatty acids and whether these
molecules possess inflammation resolution properties. The reaction of DHA,
DPAn-3, and DPAn-6 with 5-, 12-, and 15-lipoxygenases produced oxylipins,
which were identified and characterized by liquid chromatography coupled with
tandem mass-spectrometry. DPAn-6 and DPAn-3 proved to be good substrates for
15-lipoxygenase. 15-Lipoxygenase proved to be the most efficient enzyme of the
three tested for conversion of long chain polyunsaturated fatty acids to
corresponding oxylipins. Since DPAn-6 is a major component of Martek
DHA-S™ oil, we focused our attention on reaction products obtained from
the DPAn-6 and 15-lipoxygenase reaction. (17S)-hydroxy-DPAn-6 and
(10,17S)-dihydroxy-DPAn-6 were the main products of this reaction.
These compounds were purified by preparatory high performance liquid
chromatography techniques and further characterized by NMR, UV
spectrophotometry, and tandem mass spectrometry. We tested both compounds in
two animal models of acute inflammation and demonstrated that both compounds
are potent anti-inflammatory agents that are active on local intravenous as
well as oral administration. These oxygenated DPAn-6 compounds can thus be
categorized as a new class of DPAn-6-derived resolvins.Enzymatically formed oxygenation products of C-20 and C-22 long chain
polyunsaturated fatty acids
(LC-PUFAs),4 have
important biological roles in inflammation, allergies, and blood clotting and
are thus believed to have therapeutic potential in several chronic immune
diseases
(1–10)
Several biologically important products of
cis-5,8,11,14-eicosatetraenoic acid/arachidonic acid (ARA),
cis-5,8,11,14,17-eicosapentaenoic acid (EPA), and
cis-4,7,10,13,16,19-docosahexaenoic acid (DHA) have been described
(4,
11,
12). Proinflammatory
oxylipins, such as leukotrienes and some prostaglandins, are derived from ARA,
an ω-6 fatty acid. Interestingly, the same fatty acid also serves as a
precursor to anti-inflammatory or proresolution molecules like lipoxins
(13,
14). Stable analogues of
lipoxins are being developed as drugs for asthma and other inflammatory airway
diseases (15,
16). Oxylipins derived from
ω-3 fatty acids, such as DHA and EPA, known as resolvins, are primarily
anti-inflammatory in nature
(17). EPA acts as a precursor
to the E-series resolvins that have shown potential in the treatment of
colitis, arthritis, and periodontitis
(18–20).
The resolvins of the D-series derived from DHA are useful as neuroprotective
agents. 10,17-Dihydroxy-4,7,11,13,15,19-docosahexaenoic acid (10,17-HDHA) or
neuroprotectin D1 is a resolvin that is formed endogenously in the human brain
and eye and is believed to exert its protective effect against cell
injury-induced oxidative stress
(21–23).The main enzymes responsible for the production of these oxygenated LC-PUFA
products are primarily lipoxygenases and, in addition, cyclo-oxygenases and
cytochromes P450. These enzymes produce oxylipins via transcellular activity,
often involving multiple cell types
(24). This activity mainly
results in mono-, di-, and tri-hydroxylation products of fatty acids that have
varying potencies, depending on the exact structure of the compound.
Lipoxygenases are non-heme, iron-containing dioxygenases that catalyze the
regioselective and enantioselective oxidation of polyunsaturated fatty acids
containing one or more cis,cis-1,4-pentadienoic moieties to give the
corresponding hydroperoxy derivatives
(25,
26). We thus considered that,
in addition to DHA and EPA, other C-22 PUFAs containing such methylene
interrupted double bonds may also be substrates for lipoxygenases and that
resulting products may have anti-inflammatory activity similar to DHA-derived
resolvins. DPAn-6 (cis-4,7,10,13,16-docosapentaenoic acid) is present
in algal oils, and recent studies have demonstrated that this fatty acid has
anti-inflammatory activities in vitro and, in conjunction with DHA,
also has anti-inflammatory activity in
vivo.5 Also, it
has been suggested that a combination of DHA and DPAn-6 could be a beneficial
natural therapy in neuroinflammatory conditions like Alzheimer disease.
Specifically, in a 3×Tg-AD mouse model of Alzheimer disease, DPAn-6 was
shown to reduce levels of early stage phospho-Tau epitopes, which in turn
correlated with a reduction in phosphorylated c-Jun N-terminal kinase, a
putative Tau kinase (27).
Although the precise mechanism of action of DPAn-6 in these inflammatory
milieus is not known, it suggests a possible role for oxylipin products of
DPAn-6 in resolution of inflammation. Also, another LC-PUFA, DPAn-3
(cis-7,10,13,16,19-docosapentaenoic acid) usually present along with
DHA and EPA in marine oils is known to be a potent inhibitor of platelet
aggregation
(28–30).
In addition, this LC-PUFA has a potent inhibitory effect on angiogenesis
through the suppression of VEGFR-2 (vascular endothelial-cell growth factor
receptor 2) expression. Angiogenesis is known to contribute to tumor growth,
inflammation, and microangiopathy, again pointing to the possibility that
anti-inflammatory activity of DPAn-3 might be mediated through resolvin-like
products as in the case of DHA and EPA
(31).The purpose of this research was to determine whether oxylipins are formed
from the C-22 LC-PUFAs, DPAn-6 and DPAn-3, by lipoxygenase activity; to
compare them to products formed from DHA; to chemically characterize products;
to purify key oxylipin products from the DPAn-6/15-lipoxygenase reaction; and
to test whether these compounds have resolvin-like anti-inflammatory activity.
This research also sets the stage for preparation and isolation of a wide
range of other C-22 oxylipins that could be evaluated as potential
anti-inflammatory compounds. 相似文献