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排序方式: 共有143条查询结果,搜索用时 328 毫秒
41.
TOR SKRBY EDWARD D. H
GESTTT KARL-ERIK ANDERSSON 《Acta physiologica (Oxford, England)》1985,123(4):445-456
The influence of extracellular Ca2+ and nifedipine on contractile responses to 10 μM noradrenaline (NA) was investigated in isolated rat and cat middle cerebral (RCA, CCA) and mesenteric (RMA, CMA) arteries. In the CCA (containing predominantly α2-adrenoceptors), the NA-induced contractions developed considerably more slowly than in the RCA, RMA (containing mainly α1-adrenoceptors) and CMA (sensitive to both at,- and α2-adrenoceptor selective antagonists). The tonic component of the NA-induced contraction in the four types of artery was substantially suppressed after only short periods in Ca2+-free solution. In each type of artery, excluding the CCA, the contractile response to 124 mM K+ was more sensitive to Ca2+ deprivation than that to NA. This suggests that NA, besides mobilizing extracellular Ca2+, can also release Ca2+ from an intracellular pool in the RCA, RMA and CMA, but not in the CCA. Thus, α1-adrenoceptor-mediated contractions in the RCA and RMA seem to depend on both Ca2+ influx and intracellular Ca2+ release, whereas α2-adrenoceptor-mediated contractile responses in the CCA appear to rely almost entirely on Ca2+ influx. Both the maximum response and the tonic component of the NA-induced contraction were significantly more sensitive to nifedipine in the CCA than in the RCA. In comparison with the NA-induced contractions in these arteries, those in the RMA and CMA were relatively resistant to nifedipine. In the CCA exposed to NA in Ca2+-free medium, nifedipine almost abolished the contraction induced by re-addition of Ca2+, whereas in the other types of artery, Ca2+ re-application evoked a significant contraction also in the presence of the drug. The differential effects of nifedipine presumably reflect differences between the arteries, not only in the relative contribution of Ca2+ influx and intracellular Ca2+ release to the contractile activation, but also in the nifedipine sensitivity of the Ca2+ entry pathways utilized by NA. It is concluded that the mechanisms through which NA induces contraction seem to be related both to the subtype of α-adrenoceptor stimulated by NA and to the type of vessel studied. 相似文献
42.
TT病毒核酸的检测 总被引:1,自引:0,他引:1
目的初步测定献血员、慢性乙型肝炎、慢性丙型肝炎及慢性非甲~戊型,非庚型肝炎患者中TT病毒的感染情况,分析不同TT病毒感染者血清中TT病毒开放读码框架2区部分基因序列。方法以套式聚合酶链反应测定TT病毒核酸,取献血员(TX2)、慢性乙型肝炎(TX3)、慢性丙型肝炎(TX4)及慢性非甲~戊型,非庚型肝炎患者(TX1)各1例TT病毒PCR阳性产物,以双脱氧核苷酸链终止法测定核苷酸序列。结果检测20例献血员、29例慢性乙型肝炎、31例慢性丙型肝炎及32份慢性非甲~戊型,非庚型肝炎标本,TT病毒核酸阳性者分别占5.0%(1/20)、6.9%(2/29)、29.0%(9/31)和34.4%(11/32)。与N22克隆相比,TX1、TX2、TX3与TX4在核苷酸水平的同源性分别为95.41%、98.47%、97.45%和97.96%。结论本组献血员、慢性乙型肝炎、慢性丙型肝炎及慢性非甲~戊型,非庚型肝炎患者中均存在TT病毒感染者。从本组不同TT病毒感染者血清中分离出4株TT病毒序列,其开放读码框架2区部分基因序列高度保守 相似文献
43.
Connelly RJ; Hayden MS; Scholler JK; Tsu TT; Dupont B; Ledbetter JA; Kanner SB 《International immunology》1998,10(12):1863-1872
The combination of anti-CD2 mAb 9.6 and 9-1, specific for distinct
epitopes, induces proliferation of resting human T cells. The mitogenic
activity of this mAb mixture depends upon accessory cells and the 9-1 mAb
Fc domain. To further study the functional properties of these mAb, their
variable regions were cloned and expressed as monospecific single- chain Fv
(scFv) proteins fused to the human IgG1 Fc domain (scFvIg). A novel
bispecific scFvIg was constructed by cloning the two monospecific scFv
binding sites in tandem, with the 9.6 scFv placed N-terminal to the 9-1
scFvIg. Monospecific scFvIg binding to CD2 was comparable to that of the
corresponding parental mAb, while the bispecific scFvIg exhibited binding
activity similar to that of the 9-1 scFvIg. The combination of 9.6 scFvIg
and 9-1 mAb was mitogenic, whereas mixtures including the 9-1 scFvIg were
non-stimulatory, confirming the unique properties of the 9-1 IgG3 Fc.
Without the IgG3 tail, the bispecific 9.6/9-1 scFvIg was directly mitogenic
and was a more potent mitogen than the mAb mixture, but was accessory cell
dependent. Unlike the combination of mAb, the bispecific reagent did not
directly mobilize calcium in T cells. In comparison to the mAb mixture,
bispecific 9.6/9- 1 scFvIg-mediated stimulation of a mixed lymphocyte
reaction was significantly more resistant to inhibition of the CD28
co-stimulatory pathway by the inhibitor CTLA-4-Ig. These results show that
expression of the 9.6 and 9-1 binding sites together on a bispecific scFvIg
increased the mitogenic properties of the mAb and altered the degree of
accessory cell signals required for T cell activation.
相似文献
44.
Abstract – This paper reports on the presence of low numbers of Streptococcus mutans among the oral streptococci present in human dental plaque in a Sri Lanka (Ceylon) population, where the caries activity is low and a low sucrose intake is combined with the presence of heavy plaque deposits. Plaque samples of unknown age were collected from 10 individuals in a tea estate, and another 10 samples were collected from dental students 19 days following interruption of oral hygiene. Of 670 such strains of oral streptococci studied, none showed typical "frosted glass" colony morphology on Mitis Salivarius agar. However, when subjected to physiological tests 14 of them were classified as S. mutans. 相似文献
45.
炎症在启动和维持心房颤动中的地位——对研究资料的系统回顾 总被引:1,自引:0,他引:1
近年的研究显示,炎症在启动、维持心房颤动(房颤)中起非常重要的作用.美国Issac等对1995~2007年间以英文发表的有关房颤与炎症关系方面的文章,以及药物,如他汀类、血管紧张素转化酶抑制剂(ACEI)及糖皮质激素在治疗房颤中的作用方面的文章进行了系统回顾(J Am Coll Cardiol,2007, 50:2021-2028). 相似文献
46.
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49.
A prospective randomized trial of the surgical blood order equation for ordering red cells for total hip arthroplasty patients 总被引:1,自引:0,他引:1
GA Nuttall ; PJ Santrach ; WC Oliver Jr ; MH Ereth ; TT Horlocker ; ME Cabanela ; RT Trousdale ; S Bryant ; TW Currie 《Transfusion》1998,38(9):828-833
BACKGROUND: The majority of crossmatched blood is for surgical patients, and most of it is never transfused. An alternative system for ordering red cell (RBC) units, called the surgical blood order equation (SBOE), which incorporates specific patient variables for surgical patients, has been developed. STUDY DESIGN AND METHODS: A prospective double-blind randomized trial compared the SBOE with the maximal surgical blood order schedule (MSBOS) system for ordering allogeneic RBC units in 60 patients undergoing total hip arthroplasty. Autologous RBCs were available for none of the patients. RESULTS: There were no differences in patient demographic, surgical, or laboratory variables at any time. The median number (range) of allogeneic RBC units ordered was 2 (2-3) for the MSBOS and 0 (0-3) for the SBOE (p<0.0001). The SBOE ordered the correct number of RBC units for 58 percent of patients, while the MSBOS did so for 7 percent (p<0.0001). The SBOE had a lower crossmatch-to-transfusion ratio than the MSBOS (0.83 vs. 4.12). Costs were also lower with the SBOE. CONCLUSION: Incorporation of patient factors in the use of the SBOE system resulted in increased efficiency of blood-ordering practices for total hip arthroplasty. 相似文献
50.