排序方式: 共有38条查询结果,搜索用时 15 毫秒
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Popović ZB Mowrey KA Zhang Y Zhuang S Tabata T Wallick DW Grimm RA Thomas JD Mazgalev TN 《American journal of physiology. Heart and circulatory physiology》2002,283(6):H2706-H2713
Atrial fibrillation (AF) is characterized by short and irregular ventricular cycle lengths (VCL). While the beneficial effects of heart rate slowing (i.e., the prolongation of VCL) in AF are well recognized, little is known about the impact of irregularity. In 10 anesthetized dogs, R-R intervals, left ventricular (LV) pressure, and aortic flow were collected for >500 beats during fast AF and when the average VCL was prolonged to 75%, 100%, and 125% of the intrinsic sinus cycle length by selective atrioventricular (AV) nodal vagal stimulation. We used the ratio of the preceding and prepreceding R-R intervals (RR(p)/RR(pp)) as an index of cycle length irregularity and assessed its effects on the maximum LV power, the minimum of the first derivative of LV pressure, and the time constant of relaxation by using nonlinear fitting with monoexponential functions. During prolongation of VCL, there was a pronounced decrease in curvature with the formation of a plateau, indicating a lesser dependence on RR(p)/RR(pp). We conclude that prolongation of the VCL during AF reduces the sensitivity of the LV performance parameters to irregularity. 相似文献
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Sakaguchi T Kitagawa K Ando T Murakami Y Morita Y Yamamura A Yokoyama K Tamiya E 《Biosensors & bioelectronics》2003,19(2):115-121
A biochemical oxygen demand (BOD) sensing system based on bacterial luminescence from recombinant Escherichia coli containing lux A-E genes from Vibrio fischeri has been developed. It was possible to use frozen cells of luminescent recombinants of E. coli as the bacterial reagents for measurement. Steady bioluminescence was observed during the incubation time between 90 and 150 min in the presence of a sole carbon source such as glucose, acetate, L-glutamate and BOD standard solution (GGA solution). This disposable bacterial reagent was applied to measure and detect organic pollution due to biodegradable substances in various wastewaters. The obtained values of this study showed a similar correlation with that of the conventional method for BOD determination (BOD5). Bacterial luminescence that was visualized with an imaging system using a charge coupled device (CCD) camera and a photomulti-counter demonstrated that this method could also be used for multi-sample detection of organic pollution due to biodegradable substances by using a microtiter plate. These results suggested for successful achievement of high-though-put detection of BOD in practical. 相似文献
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We studied the relationship between number of diapausing eggs produced by the spider mite Panonychus mori and the subsequent population trend for a period of 3 years. Panonychus mori showed a single population density peak on its host plant moonseed, Cocculus trilobus. The position and height of this peak were correlated with the density of diapausing eggs around the moonseed leaf buds produced
the winter before. In 1994 the density of diapausing eggs measured in February was 4.3/bud, which was 6–14 times higher than
the density of diapausing eggs for the same period in 1995 (0.3/bud) and 1996 (0.7/bud). The subsequent population density
peak in 1994 occurred in mid June and was about 2.5 times higher than the peaks in 1995 and 1996, which both occurred early
September. Thus, the present study showed a positive correlation between the density of diapausing eggs on the host plant
and the start and the extend of the population increase the next growing season. Predators associated with the spider mite
population were phytoseiid mites, especially Amblyseius eharai was well synchronized with the spider mite density in 1994. Field observations revealed that P. mori produced diapausing eggs in response to short photoperiod in early October each year, which corresponded with the timing
predicted by the critical photoperiod around 13 h at 18°C, as assessed in laboratory trials. Diapause ended by early April
when egg hatchability attained about 50% and eggs took 9 days to hatch at 25°C and a 16L:8D photoperiod. Hatching in early
April was twice faster than in late February. 相似文献
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Tomotsugu?AriteEmail author Hiromu?Kameoka Junko?Kyozuka 《Journal of Plant Growth Regulation》2012,31(2):165-172
Strigolactones are recently identified plant hormones that inhibit shoot branching. Pleiotropic defects in strigolactone-deficient
or -insensitive mutants indicate that strigolactones control various aspects of plant growth and development. However, our
understanding of the hormonal function of strigolactones in plants is very limited. In this study we demonstrate that rice
dwarf mutants that are strigolactone-deficient or -insensitive exhibit a short crown root phenotype. Exogenous application of GR24,
a synthetic strigolactone analog, complemented the crown root defect in strigolactone-deficient mutants but not in strigolactone-insensitive
mutants. These observations imply that strigolactones positively regulate the length of crown roots. Histological observations
revealed that the meristematic zone is shorter in dwarf mutants than in wild type, suggesting that strigolactones may exert their effect on roots via the control of cell division.
We also show that crown roots of wild type, but not dwarf mutants, become longer under phosphate starvation. 相似文献
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Joji Ishida Manabu Onishi Kazuhiko Kurozumi Tomotsugu Ichikawa Kentaro Fujii Yosuke Shimazu Tetsuo Oka Isao Date 《Translational oncology》2014,7(2):292-302.e1
Glioblastoma is known to secrete high levels of vascular endothelial growth factor (VEGF), and clinical studies with bevacizumab, a monoclonal antibody to VEGF, have demonstrated convincing therapeutic benefits in glioblastoma patients. However, its induction of invasive proliferation has also been reported. We examined the effects of treatment with cilengitide, an integrin inhibitor, on bevacizumab-induced invasive changes in glioma. U87ΔEGFR cells were stereotactically injected into the brain of nude mice or rats. Five days after tumor implantation, cilengitide and bevacizumab were administered intraperitoneally three times a week. At 18 days after tumor implantation, the brains were removed and observed histopathologically. Next, the bevacizumab and cilengitide combination group was compared to the bevacizumab monotherapy group using microarray analysis. Bevacizumab treatment led to increased cell invasion in spite of decreased angiogenesis. When the rats were treated with a combination of bevacizumab and cilengitide, the depth of tumor invasion was significantly less than with only bevacizumab. Pathway analysis demonstrated the inhibition of invasion-associated genes such as the integrin-mediated cell adhesion pathway in the combination group. This study showed that the combination of bevacizumab with cilengitide exerted its anti-invasive effect. The elucidation of this mechanism might contribute to the treatment of bevacizumab-refractory glioma. 相似文献