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Receptor-mediated assembly of blood proteases on vascular cells maintains the hemostatic balance and initiates intracellular signal transduction. Effector cell protease receptor-1 (EPR-1) is an approximately 62-kDa vascular cell membrane receptor for the clotting protease factor Xa, participating in thrombin formation and lymphocyte activation. Here, recombinant EPR-1 fragments were engineered in the frame of intercellular adhesion molecule-1, transfected in mammalian cells, and analyzed for antibody recognition and ligand binding. Chimeric transfectants containing the EPR-1 sequence Met1-Arg60 bound the immunosuppressive anti-EPR-1 monoclonal antibody (mAb) 2E1. In contrast, transfected cells expressing the EPR-1 sequence Pro120-Ala154 were recognized by the functionally inhibitory anti-EPR-1 mAbs 9D4 and B6, bound 125I-factor Xa in a reaction quantitatively indistinguishable from that of wild-type EPR-1 transfectants, and promoted factor Xa concentration-dependent prothrombin activation in the absence of exogenous factor V/Va. Chimeric transfectants expressing the COOH terminus end of the EPR-1 extracellular domain (Ala157-Glu221) did not bind anti-EPR-1 mAbs and did not associate with factor Xa. Mutagenesis of Asn131 or Lys133 in the EPR-1 ligand recognition domain abolished factor Xa binding by 80 +/- 5.5 and 96 +/- 4%, respectively, while mutation of Lys126, Gly128, Asn129, and Asn134 was without effect. A synthetic peptide duplicating the EPR-1 sequence S123PGKPGNQNSKNEPP137 dose dependently inhibited factor V/Va-independent thrombin generation of resting endothelium (IC50 approximately 1 microM), while the adjacent EPR-1 sequence P136PKK-RERERSSHCYP150 was ineffective. These findings demonstrate that EPR-1 contains two spatially distinct functional domains implicated in lymphocyte activation (Met1-Arg60) or factor Xa binding and prothrombin activation (Pro120-Ala154). These interacting sequences may provide a novel potential target for inhibition of factor Xa-dependent vascular cell responses. 相似文献
13.
We have studied the inhibitory action of long- and short-chain fatty acids on hepatic glucose utilization in hepatocytes isolated from fasted rats. The rates of hepatic glucose phosphorylation and glycolysis were determined from the tritiated products of [2-3H] and [6-3H]glucose metabolism, respectively. The difference between these was taken as an estimate of the 'cycling' between glucose and glucose-6-phosphate. In the presence of 40 mM glucose this cycling was estimated at 0.68 mumol/min/g wet wt. Glucose phosphorylation was unaffected during palmitate and hexanoate oxidation to ketone bodies but glycolysis was inhibited. The rate of glucose cycling was increased during this phase to 1.25 mumol/min/g. Following the complete metabolism of the fatty acids, glycolysis was reinstated and cycling rates returned to control levels. Hepatic glucose cycling appears to be an important component of the glucose/fatty acid cycle. 相似文献
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The Stein paradigm was used to examine the circumstances under which verbal elaborations enhance memory in young and older adults. Subjects studied target adjectives that were embedded in one of three sentence contexts that varied in elaboration of the subject-adjective relationship: (1) nonelaborated base sentences; (2) base sentences with semantically consistent, but arbitrary verbal, elaborations; and (3) base sentences with explanatory verbal elaborations that clarified the significance of the subject-adjective relationship. The presence of the elaborations was varied at encoding and retrieval, and cued recall of the target adjectives was tested with incidental and intentional learning procedures. In Experiments 1A and 1B, explanatory elaborations at encoding and retrieval yielded the largest memorial facilitation for both young and older adults, and the benefit was comparable for the incidental and intentional learning measures. In Experiment 2, age-related differences in recall were minimal with explanatory elaborations at encoding and retrieval, but larger age differences occurred in the nonelaborated comparison conditions. In Experiment 3, explanatory elaborations present at encoding but not at retrieval enhanced recall when the original Stein stimuli were used, but not with the present stimuli. The implications of these results with regard to the mnemonic efficacy of verbal elaborations for young and older adults are discussed. 相似文献
16.
What ethical concerns regarding the application of new antidementia compounds are pertinent to the best interests of patients with Alzheimer's disease and their caregivers? Based on collected preliminary anecdotal accounts, these concerns are important and should be considered carefully by clinicians, researchers, and families. 相似文献
17.
A review of robust design methods for multiple responses 总被引:1,自引:0,他引:1
Terrence E. Murphy Kwok-Leung Tsui Janet K. Allen 《Research in Engineering Design》2005,16(3):118-132
Problems in engineering design often involve determining design variable settings to optimize individual product performance
for multiple criteria, which are often in conflict. We review mathematically rigorous techniques from the statistical literature
for finding a vector x of design variable settings, which produces an optimal compromise solution among a group of prioritized response variables.
The best compromise solution is typically gained by optimizing an objective function, which incorporates the prioritized demands
of multiple responses. Since most multi-response objective functions are constructed by combining the functions used to optimize
univariate responses, a review of the prominent univariate approaches is presented first. A multivariate approach from the
engineering literature called the compromise Decision Support Problem is also reviewed. Finally a table comparing the relative
merits of the different multivariate approaches summarizes the article in a concise and user-friendly fashion. 相似文献
18.
In this paper we present a scale model for fitting an ideal shape to an object. The measurements of the object are taken corresponding to a fixed coordinate system at a set of well-defined locations on the surface of the object. We propose an algorithm to estimate the model parameters and hypothesis tests to make statistical inferences about several possible special cases of the general model. The model is tested with an example that analyzes data on the feet of people in Hong Kong. 相似文献
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20.
Y Xu DC Gaudette JD Boynton A Frankel XJ Fang A Sharma J Hurteau G Casey A Goodbody A Mellors 《Canadian Metallurgical Quarterly》1995,1(10):1223-1232
Ascites from ovarian cancer patients contain potent growth-promoting activity toward human ovarian cancer cells both in vitro and in vivo. This activity is associated with rapid increases in cytosolic free calcium ([Ca2+]i) as a consequence of phosphoinositide hydrolysis. In this study, we describe the purification, characterization, and identification of an ovarian cancer activating factor (OCAF) from ascites of ovarian cancer patients. We have isolated OCAF by a combination of solvent extraction, silica gel chromatography, and TLC. Mass spectral analysis, phospholipase sensitivity, and gas chromatographic behavior of purified OCAF indicate that OCAF is composed of various species of lysophosphatidic acid (LPA), including LPAs with polyunsaturated fatty acyl chains (linoleic, arachidonic, and docosahexaenoic acids). However, OCAF is more potent than sn-1 palmitoyl, oleoyl, or stearoyl LPA in increasing [Ca2+]i in ovarian cancer cells. The ability of OCAF to alter [Ca2+]i is sensitive to the effects of lipoxidase, whereas the activity of sn-1 oleoyl, stearoyl, or palmitoyl LPA is not, suggesting that polyunsaturated bonds in the fatty acyl chain of OCAF may account for its increased ability to activate ovarian cancer cells. Furthermore, a sn-2 linoleoyl LPA generated by phospholipase A1 treatment of synthetic phosphatidic acid is much more active than are sn-1 palmitoyl, stearoyl, or oleoyl LPA in increasing [Ca2+]i in ovarian cancer cells. Taken together, these data suggest that the ability of OCAF to increase cellular calcium may reside in the structure and/or location of the fatty acyl chain of LPA. Purified OCAF, at concentrations similar to those present in ascites from ovarian cancer patients, was sufficient to induce proliferation of ovarian cancer cells, as indicated by thymidine incorporation, reduction of 3-(4,5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide, or colony formation. However, even at optimal concentrations of OCAF, proliferation was lower than that induced by FCS or ascites from ovarian cancer patients, indicating that, although OCAF may be a major regulator of ovarian cancer cells in vivo, it is not the sole mediator present in ascites, and it likely functions in concert with other growth factor activities. 相似文献