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71.
72.
Synthetic human beta-globin 5'HS2 constructs function as locus control regions only in multicopy transgene concatamers. 总被引:16,自引:2,他引:14
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Transgenes linked to the beta-globin locus control region (LCR) are transcribed in a copy-dependent manner that is independent of the integration site. It has previously been shown that the LCR 5'HS2 region does not require its NF-E2 dimer binding site for LCR activity. In this paper we analyse synthetic 5'HS2 core constructs containing point mutations in the other factor binding sites 3' of the NF-E2 dimer site. The results show that 5'HS2 core is a partially active LCR that functions in a concatamer of at least two copies but not when present as a single copy in transgenic mice and that no single binding site within 5'HS2 is required for position-independent expression. In addition, the H-BP factor is identical to upstream stimulatory factor (USF) and full enhancement levels by 5'HS2 core in MEL cells require a combination of all the factor binding sites. We suggest that 5'HS2 cores in a concatamer interact with each other to establish an area of open chromatin and that this process may be the basis of LCR function. 相似文献
73.
Ian P. Thompson Mark J. Bailey Richard J. Ellis Kevin J. Purdy 《FEMS microbiology letters》1993,102(2):75-84
Abstract The cellular fatty acid composition of six bacterial species isolated from the seeds and leaves of sugar beet ( Beta vulgaris ) and from soil were analysed. The quantitative data from the fatty acid methyl ester (FAME) profiles were highly reproducible. Numerical analysis of Xanthomonas maltophilia . FAME profiles sub-grouped strains according to when they were isolated in the growing season. The analytical method used was sensitive enough to differentiate strains of Klebsiella terrigena isolated from either soil or leaves. The results from this study confirm reports that analyses of bacterial FAME composition were rapid to perform, specific and allowed differentiation of strains within the same species. 相似文献
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75.
A R Gamble J A Bell J E Ronan D Pearson I O Ellis 《BMJ (Clinical research ed.)》1993,306(6873):295-298
OBJECTIVES--To determine whether variations in the expression of tumour related antigens can predict the origin of tumours. DESIGN--Immunohistological study of tumour marker expression in primary adenocarcinomas and respective metastatic deposits. Antibodies to the following tumour markers were used: polymorphic epithelial mucin (NCRC-11 and SM3), carcinoembryonic antigen, carcinoembryonic antigen with non-specific antigen co-specificity, CA125, CA19.9, prostate specific antigens, and thyroglobulin. SETTING--Histopathology department of teaching hospital. SUBJECTS--100 pathology sections of metastatic adenocarcinoma and their related primary tumours. MAIN OUTCOME MEASURES--Concordance of reactivity between primary and metastatic tumours. Reactivity profiles of tumour sites. RESULTS--The correct primary site of origin was predicted in 70% (33/47) of tumours in men and 54% (27/43) tumours in women with antibodies SM3, 288, CA19.9, CA125, and PSA (men only). Specificities ranged from 68% for breast tumour to 98% for prostate tumour. CONCLUSION--Use of tumour markers in patients presenting with metastatic adenocarcinoma of unknown origin can help localise the probable primary sites and reduce the need for extensive and expensive imaging techniques. 相似文献
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J. K. French B. F. Williams H. H. Hart S. Wyatt J. E. Poole C. Ingram C. J. Ellis M. G. Williams H. D. White 《BMJ (Clinical research ed.)》1996,312(7047):1637-1641
OBJECTIVES--To determine the proportion of patients presenting with acute myocardial infarction who are eligible for thrombolytic therapy. DESIGN--Cohort follow up study. SETTING--The four coronary care units in Auckland, New Zealand. SUBJECTS--All 3014 patients presenting to the units with suspected myocardial infarction in 1993. MAIN OUTCOME MEASURES--Eligibility for reperfusion with thrombolytic therapy (presentation within 12 hours of the onset of ischaemic chest pain with ST elevation > or = 2 mm in leads V1-V3, ST elevation > or = 1 mm in any other two contiguous leads, or new left bundle branch block); proportions of (a) patients eligible for reperfusion and (b) patients with contraindications to thrombolysis; death (including causes); definite myocardial infarction. RESULTS--948 patients had definite myocardial infarction, 124 probable myocardial infarction, and nine ST elevation but no infarction; 1274 patients had unstable angina and 659 chest pain of other causes. Of patients with definite or probable myocardial infarction, 576 (53.3%) were eligible for reperfusion, 39 had definite contraindications to thrombolysis (risk of bleeding). Hence 49.7% of patients (537/1081) were eligible for thrombolysis and 43.5% (470) received this treatment. Hospital mortality among patients eligible for reperfusion was 11.7% (55/470 cases) among those who received thrombolysis and 17.0% (18/106) among those who did not. CONCLUSIONS--On current criteria about half of patients admitted to coronary care units with definite or probable myocardial infarction are eligible for thrombolytic therapy. Few eligible patients have definite contraindications to thrombolytic therapy. Mortality for all community admissions for myocardial infarction remains high. 相似文献
78.
Apoptosis is a phenomenon previously associated exclusively with metazoan organisms. We show here that procyclic insect form Trypanosoma brucei rhodesiense, a protozoan parasite, when treated in vitro with concanavalin A displayed several features normally associated with apoptosis in metazoan cells. Lectin treatment induced cleavage of nuclear DNA into oligonucleosomal fragments, suggesting activation of an endogenous nuclease in the parasite. Treated trypanosomes, although agglutinated and non-motile, exhibited fluorescence after treatment with the vital stain fluorescein diacetate and retained (3)H-uridine indicating that their cell membranes remained intact during the period of DNA fragmentation. Electron micrographs showed characteristic morphology of cells undergoing apoptosis, including surface membrane vesiculation and migration of chromatin to the periphery of the nuclear membrane while mitochondria remained intact. These results suggest that treatment with concanavalin A triggers a cell death mechanism in T. b. rhodesiense similar to the process of apoptosis described in metazoa. 相似文献
79.
80.
Alterations in Phosphatidylcholine Metabolism of Stretch-Injured Cultured Rat Astrocytes 总被引:1,自引:1,他引:0
Robert G. Lamb Courtney C. Harper Jerry S. McKinney Beverly A. Rzigalinski Earl F. Ellis 《Journal of neurochemistry》1997,68(5):1904-1910
Abstract: The primary objective of this study was to determine the influence of stretch-induced cell injury on the metabolism of cellular phosphatidylcholine (PC). Neonatal rat astrocytes were grown to confluency in Silastic-bottomed tissue culture wells in medium that was usually supplemented with 10 µM unlabeled arachidonate. Cell injury was produced by stretching (5–10 mm) the Silastic membrane with a 50-ms pulse of compressed air. Stretch-induced cell injury increased the incorporation of [3H]choline into PC in an incubation time- and stretch magnitude-dependent manner. PC biosynthesis was increased three- to fourfold between 1.5 and 4.5 h after injury and returned to control levels by 24 h postinjury. Stretch-induced cell injury also increased the activity of several enzymes involved in the hydrolysis [phospholipase A2 (EC 3.1.1.4) and C (PLC; EC 3.1.4.3)] and biosynthesis [phosphocholine cytidylyltransferase (PCT; EC 2.7.7.15)] of PC. Stretch-induced increases in PC biosynthesis and PCT activity correlated well (r = 0.983) and were significantly reduced by pretrating (1 h) the cells with an iron chelator (deferoxamine) or scavengers of reactive oxygen species such as superoxide dismutase and catalase. The stretch-dependent increase in PC biosynthesis was also reduced by antioxidants (vitamin E, vitamin E succinate, vitamin E phosphate, melatonin, and n-acetylcysteine). Arachidonate-enriched cells were more susceptible to stretch-induced injury because lactate dehydrogenase release and PC biosynthesis were significantly less in non-arachidonate-enriched cells. In summary, the data suggest that stretch-induced cell injury is (a) a result of an increase in the cellular level of hydroxyl radicals produced by an iron-catalyzed Haber-Weiss reaction, (b) due in part to the interaction of oxyradicals with the polyunsaturated fatty acids of cellular phospholipids such as PC, and (c) reversible as long as the cell's membrane repair functions (PC hydrolysis and biosynthesis) are sufficient to repair injured membranes. These results suggest that stretch-induced cell injury in vitro may mimic in part experimental traumatic brain injury in vivo because alterations in cellular PC biosynthesis and PLC activity are similar in both models. Therefore, this in vitro model of stretch-induced injury may supplement or be a reasonable alternative to some in vivo models of brain injury for determining the mechanisms by which traumatic cell injury results in cell dysfunction. 相似文献