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排序方式: 共有1031条查询结果,搜索用时 15 毫秒
1.
Ouédraogo Dieu-Donné Tiendrébéogo Wendlassida Joelle Stéphanie Kaboré Fulgence Ntsiba Honoré 《Clinical rheumatology》2020,39(7):2069-2075
Clinical Rheumatology - Since December 2019, the pandemic caused by coronavirus disease 2019 (COVID-19) raises a real public health problem. COVID-19 appeared in Wuhan (Hubei province) in China.... 相似文献
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Ludwig Wilkens Joelle Tchinda Dagmar Burkhardt Hans Heinrich Kreipe 《Pathobiology》2002,70(4):204-208
OBJECTIVE: Comparative genomic hybridization (CGH) has been established as an informative technique in genetic analysis. However, differences in the ratio of hybridization intensities were reported for particular chromosomes, which may affect CGH results. The aim of this study was to define these differences in more detail. For this purpose, CGH results of 70 samples of bone marrow cells (BMC) with normal karyotype in conventional cytogenetics (CC) were evaluated using seven different reference DNAs and two different DNA labeling systems. METHODS AND RESULTS: CGH using fluorochrome-conjugated nucleotides for DNA labeling indicated signal deviations in 21/70 BMC samples. Deviations affected chromosomes 1 (n = 21), 2 (n = 11), 4 (n = 11), 5 (n = 9), 6 (n = 7), 7 (n = 2), 8 (n = 2), 12 (n = 5), 13 (n = 15), 14 (n = 1), 16 (n = 17), 17 (n = 11), 19 (n = 21), 20 (n = 12), and/or 22 (n = 17). None of the imbalances were confirmed by fluorescence in situ hybridization (FISH). Using digoxigenin and biotin-conjugated nucleotides in exemplary cases (n = 5) led to the disappearance of the signal deviations. Repeated CGH experiments using seven different reference DNAs showed remarkable variations in the signal deviations. CONCLUSION: Hybridization differences depend not only on the hapten or fluorochrome-labeled nucleotides used for DNA labeling, but also on the reference DNA chosen. Therefore, close control of CGH experiments is mandatory, and additional techniques such as FISH should be performed to confirm the results obtained by CGH. 相似文献
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Using the polyamine toxin philanthotoxin, which selectively blocks calcium-permeable AMPA receptors, we show that synaptic transmission onto single hippocampal interneurons occurs by afferent-specific activation of philanthotoxin-sensitive and -insensitive AMPA receptors. Calcium-permeable AMPA receptors are found exclusively at synapses from mossy fibers. In contrast, synaptic responses evoked by stimulation of CA3 pyramidal neurons are mediated by calcium-impermeable AMPA receptors. Both pathways converge onto single interneurons and can be discriminated with Group II mGluR agonists. Thus, single interneurons target AMPA receptors of different subunit composition to specific postsynaptic sites, providing a mechanism to increase the synapse-specific computational properties of hippocampal interneurons. 相似文献
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We have investigated the density of peptides required to elicit different biological responses in cytotoxic T lymphocytes (CTL), including trogocytosis (i.e., the phenomenon whereby the lymphocytes actively capture fragments of plasma membrane from those cells with which they establish an immune synapse). We have used two separate mouse models of CTL recognising defined peptides presented by MHC class I molecules. In both systems, triggering of cytotoxicity and capture of membrane components reached saturation with low densities of ligand. On the other hand, down-modulation of cell-surface levels of TCR, induction of IFN-gamma production and detection of peptide captured required much higher ligand densities. Interestingly, fratricide (i.e., killing between CTL sharing the same specificity), a mechanism proposed to account for CTL exhaustion, was detected only at antigen concentrations still well above that second threshold leading to full blown activation. Taken together, our results show that the different thresholds that govern the elicitation of different CTL functions correlate with different proportions of antigen among the target cell components being captured via trogocytosis. 相似文献
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Summary The methyl ester of amphotericin B (100 µg/ml) enhanced the infectivity of SV40 virus DNA for CV-1 cells up to 300-fold. Amphotericin B methyl ester may prove useful for augmenting cellular penetration of macromolecules and for probing biological mechanisms.With 2 Figures 相似文献
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Following preliminary experiments to determine suitable methods for studying mycoplasma survival, suspensions of Mycoplasma gallisepticum (four strains), Mycoplasma synoviae (two strains) or Mycoplasma iowae (two strains) were seeded onto replicate samples of cotton, rubber, straw, shavings, timber, food, feathers and human hair. The organisms were also seeded onto human skin, ear and nasal mucosa. All samples were cultured for viability after 4, 8, 12 and 24 h, and then daily up to 6 days. The identity of recovered mycoplasmas was confirmed by indirect immunofluorescence. All three Mycoplasma species survived for the longest time on feathers with M. gallisepticum surviving between 2 and 4 days and M. synoviae 2 to 3 days. The type strain of M. iowae remained viable for 5 days on feathers, while the field strain was still viable at the end of the 6-day experiment. This strain also survived for at least 6 days on human hair and several other materials. M. gallisepticum survived on human hair up to 3 days and one recent field isolate also survived in the nose for 24 h. Survival times of the organisms were generally less on other materials although M. gallisepticum could be isolated from straw, cotton and rubber samples after 2 days. 相似文献
8.
Clarke GN; Bourne H; Hill P; Johnston WI; Speirs A; McBain JC; Baker HW 《Human reproduction (Oxford, England)》1997,12(4):722-726
Donor insemination (DI) using cryopreserved semen commenced at The Royal
Women's Hospital in 1976. Over the next 15 years we performed 5953
treatment cycles to achieve 816 pregnancies (13.7% per cycle) and 706 live
births. In-vitro fertilization (IVF) using donor spermatozoa commenced in
1986. Over the next 5 years we performed 303 treatment cycles for 185
couples. Including subsequent transfer of cryopreserved embryos, a total of
33% of couples achieved a successful pregnancy by IVF. Statistical analysis
indicated that, for DI pregnancies, the most important semen variable was
the percentage post-thaw motility, whilst for normal fertilization in IVF
it was the pre-freeze motility. These results may be explained by the
compensatory effects of post-thaw processing of spermatozoa for IVF, but
not for DI in our clinic.
相似文献
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Maarten Milders Stephen Bell Angus Lorimer Tom MacEwan Alison McBain 《Geriatric nursing (New York, N.Y.)》2013
Cognitive stimulation (CS) is a psychological intervention for people with dementia aimed at maintaining cognitive functioning. CS provided by caregivers would allow long-term maintenance without greatly increasing demands on health services, but raises questions concerning treatment fidelity and acceptability, which were investigated in this study. Caregivers of home-living people with dementia were trained to provide CS activities to their relative with dementia. Recordings of intervention sessions and analysis of training manuals suggested adequate delivery of the intervention. Dyads continued with the activities after caregiver training had stopped. In addition, presentation of the activities without supervision from a health care professional had no detrimental effect on well-being in the caregiver or the person with dementia. The majority of caregivers indicated that, even though they experienced some burden from doing the activities with their relative, they themselves had also benefited from the intervention and intended to continue with some of the activities. 相似文献