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排序方式: 共有167条查询结果,搜索用时 15 毫秒
1.
Cell culture-based influenza vaccine manufacturing is of growing importance. Depending on virus strains, differences in infection dynamics, virus-induced apoptosis, cell lysis and virus yields are observed. Comparatively little is known concerning details of virus–host cell interaction on a cellular level and virus spreading in a population of cells in bioreactors. In this study, the infection of MDCK cells with different influenza A virus strains in lab-scale microcarrier culture was investigated by flow cytometry. Together with the infection status of cells, virus-induced apoptosis was monitored. A mathematical model has been formulated to describe changes in the concentration of uninfected and infected adherent cells, dynamics of virus particle release (infectious virions, hemagglutinin content), and the time course of the percentage composition of the cell population. 相似文献
2.
Histidine-rich protein genes and their transcripts in Plasmodium falciparum and P. lophurae 总被引:2,自引:0,他引:2
M Wallach D F Cully L O Haas W Trager G A Cross 《Molecular and biochemical parasitology》1984,12(1):85-94
The presence of histidine-rich protein (HRP) related genes and gene products in Plasmodium falciparum was demonstrated using a synthetic pentahistidine-encoding oligonucleotide and a cloned HRP cDNA probe prepared from the avian parasite P. lophurae. In Northern blotting experiments, two knobby clones of P. falciparum were found to contain a 3500 nucleotide RNA species that hybridized with the oligonucleotide and HRP cDNA probes. As this component had the expected size for an mRNA encoding an 80-90 kDa protein and was absent from two knobless clones of P. falciparum, we concluded that it represented a 'knob protein' mRNA. Using the restriction enzyme EcoRI, three identical cross-hydribizing HRP gene fragments were found in the DNA of both knobby and knobless clones of P. falciparum. These fragments differed in size from those present in P. lophurae. These results suggest that the absence of knob protein mRNA in knobless clones is not due to loss of the corresponding gene(s). 相似文献
3.
Thomas Bakken Seong Wook Kang Sunantha Kosonsiriluk Takehito Kuwayama Yupaporn Chaiseha Mohamed E. El Halawani 《Acta histochemica》2014
In the turkey, exogenous serotonin (5-hydroxytryptamine, 5-HT) increases prolactin (PRL) secretion by acting through the dopaminergic (DAergic) system. In the present study, infusion of the 5-HT2C receptor agonist, (R)(−)-DOI hydrochloride (DOI), into the third ventricle stimulates PRL secretion, whereas the 5-HT1A receptor agonist, (+/−)-8-OH-DPAT hydrobromide (DPAT), inhibits PRL secretion. Using the immediate-early gene, c-fos, as an indicator of neuronal activity, in situ hybridization histochemistry showed preferential c-fos co-localization within tyrosine hydroxylase immunoreactive neurons (the rate limiting enzyme in DA synthesis) in the areas of the nucleus preopticus medialis (POM) and the nucleus premammillaris (PMM), in response to DPAT and DOI, respectively. To clarify the involvement of 5-HT1A and 5-HT2C receptors in PRL regulation, their mRNA expression was determined on hypothalamic tissue sections from birds in different reproductive stages. A significant difference in 5-HT1A receptor was observed, with the POM of hypoprolactinemic short day and photorefractory birds showing the highest expression. 5-HT2C receptors mRNA did not change during the reproductive cycle. The data presented support the notion that DA neurons in the PMM and POM mediate the stimulatory and inhibitory effects of 5-HT, respectively, on PRL secretion and the 5-HTergic system can both stimulate and inhibit PRL secretion. 相似文献
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Gordana Leposavić Milica Perišić Nanut Ivan Pilipović Duško Kosec Nevena Arsenović-Ranin Zorica Stojić-Vukanić Jasmina Djikić Mirjana Nacka-Aleksić 《Immunobiology》2014
This study explores the role of ovarian hormones in the phenotypic shaping of peripheral T-cell pool over the reproductive lifespan of rats. For this purpose, 2-month-old prepubertally ovariectomised (Ox) rats, showing oestrogen and progesterone deficiency, and 11-month-old Ox rats, exhibiting only progesterone deficiency, were examined for thymus output, and cellularity and composition of major TCRαβ+ peripheral blood lymphocyte (PBL) and splenocyte subsets. Although ovariectomy increased thymic output in both 2- and 11-month-old rats, the count of both CD4+ and CD8+ PBLs and splenocytes increased only in the former. In the blood and spleen of 11-month-old Ox rats only the count of CD8+ cells increased. Although ovariectomy affected the total CD4+ count in none of the examined compartments from the 11-month-old rats, it increased CD4+FoxP3+ PBL and splenocyte relative proportions over those in the age-matched controls. The age-related differences in the cellularity and the major subset composition in Ox rats were linked to the differences in the ovarian steroid hormone levels registered in 2- and 11-month-old rats. The administration of progesterone to Ox rats during the seven days before the sacrificing confirmed contribution of this hormone deficiency to the ovariectomy-induced changes in the TCRαβ+ PBL and splenocyte pool from 11-month-old rats. The expansion of the CD8+ splenocyte subset in the 11-month-old Ox rats reflected increases in cellularity of memory and, particularly, naïve cells. This was due to greater thymic output of CD8+ cells and homeostatic proliferation than apoptosis in 11-month-old Ox rats when compared with age-matched sham-Ox control rats. The homeostatic changes within CD8+ splenocyte pool from 11-month-old Ox rats, most likely, reflected the enhanced splenic IL-7 and TGF-β mRNA expression. Overall, in adult female rats, circulating oestrogen and progesterone provide maintenance of T-cell counts, a diversity of T-cell repertoire, and the main T-cell subset composition in the periphery. Progesterone deficiency affects mainly the CD8+ lymphocyte compartment through increasing thymic CD8+ cell export and upsetting homeostatic regulation within the CD8+ splenocyte pool. These alterations were reversible through progesterone supplementation. 相似文献
6.
Lene Tandle Lyngstad Bente Silnes Tandberg Hanne Storm Birgitte Lenes Ekeberg Atle Moen 《Early human development》2014
Background
Skin-to-skin contact reduces pain response in preterm infants subjected to minor painful procedures, such as heel lance. Diaper change is a procedure performed several times daily in hospitalized preterm infants. Routine care giving tasks such as diaper change may be stressful for the infant.Aims
The purpose of this study was to investigate whether diaper change induces stress and if skin-to-skin contact could reduce such stress, measured by changes in skin conductance.Study design
This was a randomized crossover pilot study in 19 preterm infants with gestational age between 28 and 34 weeks. The diaper change procedure was done twice in each infant, once during skin-to-skin contact, and once in incubator or bed with the mother present.Outcome measures
During diaper change heart rate (HR), peripheral oxygen saturation (SpO2), and changes in skin conductance (SC) peaks per sec, using the Skin Conductance Algesimeter (SCA), were registered.Results
The mean SC peaks/sec increased/decreased significantly under/after change of diapers which thereby underpins that this is a stressful procedure for the preterm infant.Skin-to-skin contact (SSC) entails significantly lower stress levels (p < 0.05) compared to diaper changed in an incubator/bed measured by the SCA.Conclusions
Diaper change is a stressful procedure for preterm infants and may be ameliorated by skin-to-skin contact. 相似文献7.
淫羊藿甙、菟丝子提取物对雄激素部分缺乏大鼠生殖保护作用的比较研究 总被引:12,自引:0,他引:12
目的 探讨淫羊藿甙、菟丝子提取物对雄激素部分缺乏大鼠的生殖保护作用.方法 以环磷酰胺造成生殖系统受损、雄激素部分缺乏大鼠模型,灌胃淫羊藿甙和菟丝子提取物7 d后,检测血清睾酮、黄体生成素(LH)、卵泡刺激素(FSH)含量;以HE染色和原位末端标记法(TUNEL)检测,光镜下观察睾丸组织、阴茎海绵体平滑肌细胞变化情况.结果 ①血清睾酮水平:淫羊藿甙组明显高于空白组和模型组,但低于睾酮组(P<0.05);菟丝子提取物组高于模型组,低于睾酮组(P<0.05),但与空白组间无统计学差异.②血清LH、FSH水平各组间均未见明显统计学差异.③阴茎海绵体平滑肌细胞的凋亡率:睾酮组和淫羊藿甙组明显低于模型组(P<0.05);菟丝子组与模型组则未见明显统计学差异.结论 淫羊藿甙、菟丝子提取物对雄激素部分缺乏大鼠均具有生殖保护作用,但淫羊藿甙作用效果强于菟丝子提取物. 相似文献
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10.
A recombinant Semliki Forest virus (SFV) RNA construct, SFV1-mCB(2) RNA, was employed for the high-level expression of the murine CB(2) (mCB(2)) cannabinoid receptor in baby hamster kidney cells. Biosynthetic radiolabel incorporation studies in concert with urea-sodium dodecylsulfate-polyacrylamide gel electrophoresis (urea-SDS-PAGE) and western immunoblotting revealed that two major proteins of approximately 26 and 40kDa were produced by the construct. The 40kDa product, but not the 26kDa product, was glycosylated as determined by 2-deoxy-D-glucose incorporation and peptide-N-glycosidase F digestion analysis. Assessment of [3H]CP55940 ([3H]-(-)-cis-3-[2-hydroxy-4-(1,1-dimethylheptyl)phenyl]-trans-4-(3-hydroxypropyl)cyclohexanol) binding data for membranes of cells transfected with SFV1-mCB(2) RNA indicated a K(d) of 0.35+/-0.04nM and a B(max) of 24.4+/-2.7pmol/mg. A rank order of binding affinities for cannabinoids, which paralleled that reported for native mCB(2) receptors, was observed. The CB(2) receptor-specific antagonist SR144528 (N-[(1S)-endo-1,3,3-trimethyl bicyclo[2.2.1]heptan-2-yl]-5-(4-chloro-3-methylphenyl)-1-(4-methylbenzyl)-pyrazole-3-carboxamide) blocked binding of [3H]CP55940, while the CB(1) receptor-specific antagonist SR141716A [N-(piperidin-1-yl)-5-(4-chlorophenyl)-1-(2,4-dichlorophenyl)-4-methyl-1H-pyrazole-3-carboxamide hydrochloride] had a minimal effect. These results indicate that the recombinant receptor expressed from SFV1-mCB(2) RNA exhibits properties, including ligand binding features, that are consistent with those for the native mCB(2) receptor. However, the presence of both 26 and 40kDa receptor species is consistent with alternative translation from two AUG start sites using the SFV1-mCB(2) RNA expression system. 相似文献