排序方式: 共有97条查询结果,搜索用时 234 毫秒
71.
72.
Ans Timmermans Melanie C. Melendrez Youry Se Ilin Chuang Nou Samon Nichapat Uthaimongkol Chonticha Klungthong Wudtichai Manasatienkij Butsaya Thaisomboonsuk Stuart D. Tyner Sareth Rith Viseth Srey Horm Richard G. Jarman Delia Bethell Nitima Chanarat Julie Pavlin Tippa Wongstitwilairoong Piyaporn Saingam But Sam El Mark M. Fukuda Sok Touch Ly Sovann Stefan Fernandez Philippe Buchy Lon Chanthap David Saunders 《PloS one》2016,11(3)
73.
74.
Ninety ejaculates from a total of 76 AI boars were extended in Beltsville Thawing Solution (BTS). Boar identity, breed, weight
of the ejaculate and sperm concentration were registered. Motility and acrosome integrity were assessed after storage at 16–18°C
for 6, 30, 54, 78, and 102 h. Storage time had a significant influence on both motility (p < 0.01) and acrosome integrity
(p < 0.001). The Least Square Means for percentage of motility showed a small decline from 79.8% after 6 h of storage to 78.4%
at 102 h. Motility at 78 and 102 h was significantly different from motility at 6 h (p < 0.05). The percentage of sperm cells
with normal acrosomes declined throughout the experiment. The Least Square Means for 6, 30, 54, 78, and 102 h of storage were
93.9%, 90.6%, 88.0%, 84.8%, and 78.2%, respectively. The decrease in acrosome integrity from one storage time to the next
was highly significant throughout the trial (p < 0.001). There was a significant influence of boar (p < 0.001) and sperm concentration
(p < 0.01) on motility, while acrosome integrity was affected only by boar (p < 0.001). Breed of the boars and weight of the
ejaculate did not influence the dependent variables. 相似文献
75.
76.
The nitrone 4 (4,5-dideoxy-4-hydroxylamino-3,4-O-isopropylidene-L-lyxofuranose) was synthesised from D-ribose and used as key intermediate for the preparation of fucosidase inhibitors. We describe two transformations of 4. Hydrolysis with aqueous sulfur dioxide gave the known potent nanomolar inhibitor 4-amino-4,5-dideoxy-L-lyxofuranose (3). 1,3-Dipolar cycloaddition with enol ethers led to the related 1,2,5,6-tetradeoxy-2,5-imino-L-altroheptonic ester 2a, acid 2b and the corresponding heptitol 2c. The new iminosugars have been evaluated for their inhibitory activity against α-L-fucosidase from bovine kidney. The alcohol 2c turned out to be a potent inhibitor in the same range as the amino-sugar 3 (K(i)=8 vs 10nM). 相似文献
77.
Ilana T. Balassiano Joaquim dos Santos-Filho Juliana M. Vital-Brazil Simone A. Nouér Claudia R. C. Souza Jon S. Brazier Eliane de O. Ferreira Regina M. C. P. Domingues 《Antonie van Leeuwenhoek》2011,99(2):249-255
Clostridium difficile is an important nosocomial enteric pathogen and is the etiological agent of pseudomembranous colites. Recently, the rates
of C. difficile infection (CDI) have increased worldwide, but in Brazil few data about this situation and the incidence of clonal types of
C. difficile exist. This study aimed to isolate and characterize C. difficile strains from samples obtained of a university hospital (HUCFF) in Rio de Janeiro city, Brazil. CDI was identified by ELISA
in 27.1% of HUCFF-in-patients enrolled in the study, and the bacterium was recovered from eight of these fecal samples. All
strains, except one, presented tcdA and tcdB genes and presented neither the cdtA and cdtB genes nor any significant deletions in the tcdC gene. All strains were sensitive to metronidazole, vancomycin and moxifloxacin, and resistant to clindamycin, ciprofloxacin
and levofloxacin. PCR-ribotyping and PFGE revealed four different clonal types among the isolates. The Brazilian PCR-ribotype
133 accounted for 50% of strains isolated, and PCR-ribotype 233 strains were obtained from 25% of the in-patients. The prevalence
and resurgence of the Brazilian PCR-ribotype 133 among the hospitalized patients of HUCFF was established, and cross-infection
of different patients associated to the same PCR-ribotypes was detected. Our results emphasize the importance of the diagnosis
and control of CDI in order to prevent the emergence of specific clones that can lead to C. difficile-associated outbreaks in Brazilian hospitals. 相似文献
78.
Munir S Hillyer P Le Nouën C Buchholz UJ Rabin RL Collins PL Bukreyev A 《PLoS pathogens》2011,7(4):e1001336
We recently demonstrated that the respiratory syncytial virus (RSV) NS1 protein, an antagonist of host type I interferon (IFN-I) production and signaling, has a suppressive effect on the maturation of human dendritic cells (DC) that was only partly dependent on released IFN-I. Here we investigated whether NS1 affects the ability of DC to activate CD8+ and CD4+ T cells. Human DC were infected with RSV deletion mutants lacking the NS1 and/or NS2 genes and assayed for the ability to activate autologous T cells in vitro, which were analyzed by multi-color flow cytometry. Deletion of the NS1, but not NS2, protein resulted in three major effects: (i) an increased activation and proliferation of CD8+ T cells that express CD103, a tissue homing integrin that directs CD8+ T cells to mucosal epithelial cells of the respiratory tract and triggers cytolytic activity; (ii) an increased activation and proliferation of Th17 cells, which have recently been shown to have anti-viral effects and also indirectly attract neutrophils; and (iii) decreased activation of IL-4-producing CD4+ T cells--which are associated with enhanced RSV disease--and reduced proliferation of total CD4+ T cells. Except for total CD4+ T cell proliferation, none of the T cell effects appeared to be due to increased IFN-I signaling. In the infected DC, deletion of the NS1 and NS2 genes strongly up-regulated the expression of cytokines and other molecules involved in DC maturation. This was partly IFN-I-independent, and thus might account for the T cell effects. Taken together, these data demonstrate that the NS1 protein suppresses proliferation and activation of two of the protective cell populations (CD103+ CD8+ T cells and Th17 cells), and promotes proliferation and activation of Th2 cells that can enhance RSV disease. 相似文献
79.
80.
Alpha2A-adrenoceptors strengthen working memory networks by inhibiting cAMP-HCN channel signaling in prefrontal cortex 总被引:5,自引:0,他引:5
Wang M Ramos BP Paspalas CD Shu Y Simen A Duque A Vijayraghavan S Brennan A Dudley A Nou E Mazer JA McCormick DA Arnsten AF 《Cell》2007,129(2):397-410
Spatial working memory (WM; i.e., "scratchpad" memory) is constantly updated to guide behavior based on representational knowledge of spatial position. It is maintained by spatially tuned, recurrent excitation within networks of prefrontal cortical (PFC) neurons, evident during delay periods in WM tasks. Stimulation of postsynaptic alpha2A adrenoceptors (alpha2A-ARs) is critical for WM. We report that alpha2A-AR stimulation strengthens WM through inhibition of cAMP, closing Hyperpolarization-activated Cyclic Nucleotide-gated (HCN) channels and strengthening the functional connectivity of PFC networks. Ultrastructurally, HCN channels and alpha2A-ARs were colocalized in dendritic spines in PFC. In electrophysiological studies, either alpha2A-AR stimulation, cAMP inhibition or HCN channel blockade enhanced spatially tuned delay-related firing of PFC neurons. Conversely, delay-related network firing collapsed under conditions of excessive cAMP. In behavioral studies, either blockade or knockdown of HCN1 channels in PFC improved WM performance. These data reveal a powerful mechanism for rapidly altering the strength of WM networks in PFC. 相似文献