Conservative management of residual and recurrent lesions after carotid endarterectomy: Long-term results

AbstractPurpose: To document the natural history of residual and recurrent carotid stenoses that are initially treated without surgery, and to identify risk factors for recurrent stenosis. Methods: Review of data from a prospective carotid database with clinical and duplex follow-up. Analysis of rate of restenosis and rate of late reoperation by life table. Risk factor analysis by χ2 and LEE-DESU statistics. Results: Three hundred forty-eight patients were available for follow-up, with 12 residual lesions (3.7%) and 22 recurrent lesions (6.6%). Rate of recurrent stenosis by life table analysis was 8.7% and 13% at 3 and 5 years. Restenosis was associated with smoking (p = 0.04) and contralateral progression. Only 21% of patients were underwent an operation within 5 years (p = 0.007) of restenosis developing, but eventually 10 of 22 patients required reoperation at long-term follow-up, eight for symptoms and two for progressive proximal stenoses. The late stroke rate was increased in patients who had residual or recurrent lesions compared with those who had normal duplex study results (18% vs 6%; p = 0.16) and was related to the ipsilateral artery. Conclusions: Recurrent lesions that remain asymptomatic can be managed without operation with likelihood of success in the near term (5 years). However, these patients are at increased risk of late stroke, and almost half will eventually require operation. Therefore, in good-risk patients operation for asymptomatic restenoses should be considered. (J Vasc Surg 1997;26:963-72.

Stringent response of Escherichia coli: revisiting the bibliome using literature mining

Understanding the mechanisms responsible for cellular responses depends on the systematic collection and analysis of information on the main biological concepts involved. Indeed, the identification of biologically relevant concepts in free text, namely genes, tRNAs, mRNAs, gene products and small molecules, is crucial to capture the structure and functioning of different responses. Results In this work, we review literature reports on the study of the stringent response in Escherichia coli. Rather than undertaking the development of a highly specialised literature mining approach, we investigate the suitability of concept recognition and statistical analysis of concept occurrence as means to highlight the concepts that are most likely to be biologically engaged during this response. The co-occurrence analysis of core concepts in this stringent response, i.e. the (p)ppGpp nucleotides with gene products was also inspected and suggest that besides the enzymes RelA and SpoT that control the basal levels of (p)ppGpp nucleotides, many other proteins have a key role in this response. Functional enrichment analysis revealed that basic cellular processes such as metabolism, transcriptional and translational regulation are central, but other stress-associated responses might be elicited during the stringent response. In addition, the identification of less annotated concepts revealed that some (p)ppGpp-induced functional activities are still overlooked in most reviews. Conclusions In this paper we applied a literature mining approach that offers a more comprehensive analysis of the stringent response in E. coli. The compilation of relevant biological entities to this stress response and the assessment of their functional roles provided a more systematic understanding of this cellular response. Overlooked regulatory entities, such as transcriptional regulators, were found to play a role in this stress response. Moreover, the involvement of other stress-associated concepts demonstrates the complexity of this cellular response