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A patient with pheochromocytoma presented striking electrocardiographic changes mimicking ischemic heart disease at one time and acute pulmonary embolism at other times. Diffuse left ventricular hypokinesia was demonstrated in the presence of normal coronary arteries. Following removal of the pheochromocytoma, the electrocardiographic abnormalities disappeared.  相似文献   
113.
屈强比对高强钢断裂韧性的影响   总被引:7,自引:0,他引:7  
通过控制组织形态,对化学尬发相同,屈强比不同的两种钢材进行三点弯曲CTOD试验,并利用三维有限元法分析裂纹法端的应力应变分布。结果表明,高屈强比的材料,由于裂纹尖端应力水平高,脆性启裂CTOD值δc明显低于低屈强比的材料;而对有延性裂纹扩展的CTOD临界值δu和δm,高屈强比的材料同于低屈强比双相钢,这是因为低屈强比材料内部存在微观组织非均质,有应变集中所致。  相似文献   
114.
Two digital methods are proposed for the solution of the time-domain approximation problem. Tho first method, based on a reeursivo algorithm for tho matrix pseudo-iriverso, determines the pulse transfer function of a discrete-timo system of a prescribed order providing the best fit in tho least squares sense at tho samplo points. Tho continuous-time system transfer function is then derived by using a simple transformation provided that tho sampling frequence oxeeeds tho Nyquist rate. Tho method is direct and computationally efficient. The second method is based on using an offieiont gradient search algorithm providing the best fit in the least pti sense at tho samplo points. A number of examples illustrato the methods  相似文献   
115.
The effects of ginsenoside-Rh1 and Rh2 in the induction of nitric oxide (NO) synthesis by IFN-gamma plus LPS were investigated using murine peritoneal macrophages. The NO production from rIFN gamma plus LPS-treated macrophages was markedly reduced by ginsenoside-Rh1 or Rh2 in a dose dependent manner, but had no inhibitory effects by ginsenoside-Rb1, Rc or Re. In addition, treatment of the cells with ginsenoside-Rh2 6 hr before the stimulation with IFN-gamma plus LPS showed more inhibitory effect than the treatment with ginsenoside-Rh2 6 hr after or simultaneously with the stimulation with IFN-gamma plus LPS in the NO production. Ginsenoside-Rh2 also effectively inhibited IFN-gamma induced NO production when the cells were treated with IFN-gamma 6 hr after the treatment with ginsenoside-Rh2. Our findings suggest that this phenomenon might be caused by inhibition of priming signal such as IFN-gamma for the synergistic induction of NO synthesis.  相似文献   
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This study shows markedly different isotype distributions of antibodies to asexual blood stages of Plasmodium falciparum and to merozoite surface protein 1 in clinically immune Senegalese adults depending on the study site. The relationships between immunoglobulin M (IgM) and IgG and between IgG3 and IgG1 antibodies differed in settings where transmission is perennial compared to settings where it is seasonal. This suggests a role for antibody class and/or subclass production and utilization in the regulation of protective immunity to such antigens.  相似文献   
118.
The anti-SRYD monoclonal antibody (mAbSRYD) raised against the IASRYDQL synthetic octapeptide, the 250-257 sequence of the Leishmania major surface glycoprotein gp63 recognizes both SRYD-containing peptides and the whole cognate major surface protein on intact parasites. Two SRYD-containing peptides, which antigenically and functionally mimic the RGDS sequence of fibronectin and efficiently inhibit parasite attachment to the macrophage receptors, were studied by two-dimensional transferred nuclear Overhauser effect experiments in the presence of mAbSRYD. The antibody-bound IASRYDQL octapeptide solution conformation was determined on the basis of 55 interproton-distance restraints, derived from NMR measurements. Eighteen structures which were first generated using an approach combining distance geometry and molecular dynamics, converge by energy minimization toward a folded structure with an average rmsd from the experimental data of less than 0.05 nm for the overall backbone and 0.025 nm for the SRYD motif. A distorted gamma-turn was found, stabilized by the backbone-backbone D255-NH to R253-CO hydrogen bond, while the R253 and D255 side chains are pointing in opposite directions. This latter antibody-bound structure is compared with that of the free octapeptide in dimethylsulfoxide solution, and with the crystal structure of the RYD fragment in OPG2 Fab, an antireceptor antibody that mimics the RGD cell adhesion site. On this basis, a mechanism for IASRYDQL-receptor interaction is discussed.  相似文献   
119.
Skeletal muscle biopsies from 18 children and 8 from their mothers were studied in mitochondrial myopathies. It is shown that by means of electron microscopy, histochemistry, and morphometry the correct diagnosis of mitochondrial insufficiency is quite possible.  相似文献   
120.
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