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51.
DL Newton S Walbridge SM Mikulski W Ardelt K Shogen SJ Ackerman SM Rybak RJ Youle 《Canadian Metallurgical Quarterly》1994,14(2):538-544
Purkinje cell toxicity is one of the characteristic features of the Gordon phenomenon, a syndrome manifested by ataxia, muscular rigidity, paralysis, and tremor that may lead to death (Gordon, 1933). Two members of the RNase superfamily found in humans, EDN (eosinophil-derived neurotoxin) and ECP (eosinophil cationic protein), cause the Gordon phenomenon when injected intraventricularly into guinea pigs or rabbits. We have found that another member of the RNase superfamily, an antitumor protein called onconase, isolated from Rana pipiens oocytes and early embryos, will also cause the Gordon phenomenon when injected into the cerebrospinal fluid of guinea pigs at a dose similar to that of EDN (LD50, 3-4 micrograms). Neurologic abnormalities of onconase-treated animals were indistinguishable from those of EDN-treated animals, and histology showed dramatic Purkinje cell loss in the brains of onconase-treated animals. The neurotoxic activity of onconase correlates with ribonuclease activity. Onconase modified by iodoacetic acid to eliminate 70% and 98% of the ribonuclease activity of the native enzyme displays a similar decrease in ability to cause the Gordon phenomenon. In contrast, the homologous bovine pancreatic RNase A injected intraventricularly at a dose 5000 times greater than the LD50 dose of EDN or onconase is not toxic and does not cause the Gordon phenomenon. A comparison of the RNase activities of EDN, onconase, and bovine pancreatic RNase A using three pancreatic RNA substrates demonstrates that onconase is orders of magnitude less active enzymatically than EDN and RNase A. Thus, another member of the RNase superfamily in addition to EDN and ECP can cause the Gordon phenomenon.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
52.
Hart D. Novosel D. Calero F. Udren E. LiFeng Yang 《Power Delivery, IEEE Transactions on》1996,11(3):1274-1284
This paper describes the testing of a new power system numerical relaying concept. The new technique is applied to distance relaying to offer improved reliability and security of the relay, and improve the speed of relay operation. To validate the algorithm's performance, the scheme was analyzed under a variety of test conditions and compared with conventional relay concepts. This paper presents the results of the testing and shows that the new relaying scheme operated with a high level of security and dependability for all of the test cases. The tests show improvements that the new scheme can offer in comparison to the conventional schemes 相似文献
53.
If the previous restorative therapy or dental caries has resulted in substantial loss of tooth structure, the abutment teeth for fixed prosthodontic restorations require a core reconstruction or a post and core. Small dentin defects can be restored with bonded cores; more extensive dentin defects that are often accompanied by previous endodontic treatment generally require additional support for the core material. A direct procedure with a bonded post is a viable treatment method. The decision to use either light-conducting all-ceramic zirconium or titanium as a post material depends on the aesthetic requirements present. The indications for a cast post and core as an indirect procedure for prosthodontic reconstructions appear to be decreasing. The learning objective of this article is to review the past and current post and core materials and techniques. Indications for core reconstruction with vital teeth and posts and cores for pulpless teeth are discussed. 相似文献
54.
Insulin-like growth factor I activates the invasion suppressor function of E-cadherin in MCF-7 human mammary carcinoma cells in vitro 总被引:1,自引:0,他引:1
ME Bracke BM Vyncke EA Bruyneel SJ Vermeulen GK De Bruyne NA Van Larebeke K Vleminckx FM Van Roy MM Mareel 《Canadian Metallurgical Quarterly》1993,68(2):282-289
The calcium-dependent cell-cell adhesion molecule E-cadherin has been shown to counteract invasion of epithelial neoplastic cells. Using three monoclonal antibodies, we have demonstrated the presence of E-cadherin at the surface of human MCF-7/6 mammary carcinoma cells by indirect immunofluorescence coupled to flow cytometry and by immunocytochemistry. Nevertheless, MCF-7/6 cells failed to aggregate in a medium containing 1.25 mM CaCl2, and they were invasive after confrontation with embryonic chick heart fragments in organ culture. Treatment of MCF-7/6 cells with 0.5 microgram ml-1 insulin-like growth factor I (IGF-I) led to homotypic aggregation within 5 to 10 min and inhibited invasion in vitro during at least 8 days. The effect of IGF-I on cellular aggregation was insensitive to cycloheximide. However, monoclonal antibodies that interfered with the function of either the IGF-I receptor (alpha IR3) or E-cadherin (HECD-1, MB2) blocked the effect of IGF-I on aggregation. The effects of IGF-I on aggregation and on invasion could be mimicked by 1 microgram ml-1 insulin, but not by 0.5 microgram ml-1 IGF-II. The insulin effects were presumably not mediated by the IGF-I receptor, since they could not be blocked by an antibody against this receptor (alpha IR3). Our results indicate that IGF-I activates the invasion suppressor role of E-cadherin in MCF-7/6 cells. 相似文献
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Male Swiss-Webster mice were rendered tolerant to morphine by subcutaneous implantation of a morphine pellet, each containing 75 mg morphine base, for 3 days. Mice implanted with placebo pellets served as controls. A high degree of tolerance to the analgesic effect of morphine developed as evidenced by decreased analgesic response to various doses of morphine. A selective kappa-opiate agonist, U-50,488H (8, 16 and 32 mg/kg, i.p.) produced dose-dependent analgesic and hypothermic effects in mice implanted with placebo pellets. A significant decrease in the analgesic and hypothermic effects of U-50,488H was observed in morphine tolerant mice as compared to placebo-treated mice. Mice were rendered tolerant to U-50,488H by injecting the drug (25 mg/kg, i.p.) twice daily for 4 days. Vehicle injected mice served as controls. Tolerance to the analgesic and hypothermic effects of U-50,488H in mice injected chronically with the drug was evidenced by the decreases in the intensity of these responses when compared to those observed in vehicle injected controls. Morphine produced a dose-dependent analgesic and hypothermic effects in mice injected chronically with vehicle but the intensity of these effects was significantly lower in mice injected chronically with U-50,488H. These results indicate that a substantial tolerance to analgesic and hypothermic effects of U-50,488H develops in morphine tolerant mice. The effect of chronic injections of U-50,488H on the binding of [3H]ethylketocyclazocine (EKC) and [3H]D-Ala2,MePhe4,Gly-ol5-enkephalin (DAMGO) to whole brain and spinal cord kappa- and mu-opiate receptors was determined.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
59.
The authors propose a behavioral decision theory relevant to the maintenance of desirable identities. The theory, termed deviance regulation theory (DRT), predicts that actions translate into meaningful identities to the extent that they cause the individual to deviate from reference group norms. This straightforward proposition is used to predict the patterning of behavior across a wide array of social contexts. The authors present evidence that predictions generalize across Eastern and Western cultures and to both personal and collective identities. Finally, they show how DRT alters current theoretical assumptions about social motives and social and cultural influence, and they illustrate how it can help explain the structure of both informal and formal social forces. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
60.
Tuberculous meningitis remains an important illness that can be difficult to diagnose in a timely fashion and carries significant morbidity. We present a retrospective review of the cases of tuberculous meningitis diagnosed and treated at a single institution. Fifty-eight cases were identified and stratified according to stage of disease at presentation. Four patients (7%) died; three (5%) developed severe neurological sequelae. Poor outcomes were largely confined to cases presenting in an advanced stage and at the extremes of age. Corticosteroids were administered to 56 patients and may have contributed to the comparatively good outcome in these cases. 相似文献