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JR Eshleman PS Donover SJ Littman SE Swinler GM Li JD Lutterbaugh JK Willson P Modrich WD Sedwick SD Markowitz ML Veigl 《Canadian Metallurgical Quarterly》1998,16(9):1125-1130
We describe a novel mutator phenotype in the Vaco411 colon cancer cell line which increases the spontaneous mutation rate 10-100-fold over background. This mutator results primarily in transversion base substitutions which are found infrequently in repair competent cells. Of the four possible types of transversions, only three were principally recovered. Spontaneous mutations recovered also included transitions and large deletions, but very few frameshifts were recovered. When compared to known mismatch repair defective colon cancer mutators, the distribution of mutations in Vaco411 is significantly different. Consistent with this difference, Vaco411 extracts are proficient in assays of mismatch repair. The Vaco411 mutator appears to be novel, and is not an obvious human homologue of any of the previously characterized bacterial or yeast transversion phenotypes. Several hypotheses by which this mutator may produce transversions are presented. 相似文献
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This study examined the relationships between social and demographic characteristics (ie, gender, race, year in school, desired residency choice, and socioeconomic background), motivations for entering the profession of podiatric medicine (extrinsic and intrinsic rewards), and negative attitudes toward treating elderly patients. The study used ordinary least squares multiple regression models to analyze data from a random, national sample of 448 podiatric medical students. In particular, the ordinary least squares models were developed to determine the independent effect of intrinsic and extrinsic rewards on negative attitudes toward treating elderly patients. Consistent with the study hypotheses, after adjusting for social and demographic characteristics, the study found extrinsic rewards to have strong positive relationships with negative attitudes toward treating elderly patients, and intrinsic rewards to have strong negative relationships with negative attitudes toward treating elderly patients. The authors discussed the implications of the findings for podiatric physicians and educators training podiatric medical students. 相似文献
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Robbins Steven B.; May Therese M.; Corazzini John G. 《Canadian Metallurgical Quarterly》1985,32(4):641
Used a national sample of 205 university and college counseling center staff members to obtain ratings of Ss' perceptions of changes in client presenting problems, changes in agency expectations with regard to 9 service-related tasks, and their comfort and skill in performing these tasks. Ratings were obtained from past and present time perspectives to aid in assessing perceived changes in these areas. Results indicate that Ss perceived client problems to be changing from more informational/educational to more serious emotional/behavioral problem areas. At the same time, staff members across all experience levels reported an increased pressure to perform in 7 of the 9 tasks listed. Staff members generally rated themselves as able to meet current service demands. Implications for counseling training programs indicate that an emphasis on acquiring traditional therapy and assessment skills may become increasingly important and that opportunities for specialty training should be expanded. (9 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
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MJ Pettinari GJ Vazquez N Krüger PS Vary A Steinbüchel BS Méndez 《Canadian Metallurgical Quarterly》1998,49(6):737-742
A Bacillus megaterium genomic fragment, which encoded an activator homologous to sigma 54 regulators and which was capable of activating Escherichia coli ato genes in trans, was detected in a gene library of B. megaterium screened for beta-ketothiolase activity. The fragment presented only one complete open reading frame (ORF1), which encoded a protein of 398 amino acids. The recombinant plasmid complemented mutations in the Escherichia coli atoC regulatory gene. The constitutive expression of the E. coli ato operon mediated by ORF1 could be useful for the synthesis of polyhydroxyalkanoates with different flexibility properties by recombinant E. coli strains. 相似文献