Copy number variation alters local and global mutational tolerance.

Copy number variants (CNVs), duplications and deletions of genomic sequences, contribute to evolutionary adaptation but can also confer deleterious effects and cause disease. Whereas the effects of amplifying individual genes or whole chromosomes (i.e., aneuploidy) have been studied extensively, much less is known about the genetic and functional effects of CNVs of differing sizes and structures. Here, we investigated Saccharomyces cerevisiae (yeast) strains that acquired adaptive CNVs of variable structures and copy numbers following experimental evolution in glutamine-limited chemostats. Although beneficial in the selective environment, CNVs result in decreased fitness compared with the euploid ancestor in rich media. We used transposon mutagenesis to investigate mutational tolerance and genome-wide genetic interactions in CNV strains. We find that CNVs increase mutational target size, confer increased mutational tolerance in amplified essential genes, and result in novel genetic interactions with unlinked genes. We validated a novel genetic interaction between different CNVs and BMH1 that was common to multiple strains. We also analyzed global gene expression and found that transcriptional dosage compensation does not affect most genes amplified by CNVs, although gene-specific transcriptional dosage compensation does occur for ∼12% of amplified genes. Furthermore, we find that CNV strains do not show previously described transcriptional signatures of aneuploidy. Our study reveals the extent to which local and global mutational tolerance is modified by CNVs with implications for genome evolution and CNV-associated diseases, such as cancer.

The Impact of Three Alternate Nicotine-Delivery Products on Combusted Cigarette Use: A Randomized Controlled Trial.

INTRODUCTION: Smoking cessation is a critical public health goal. This study examined the ability of e-cigarettes and very low nicotine cigarettes (VLNCs) to serve as cigarette substitutes and whether a substitution was supported by steady-state nicotine from a nicotine patch. AIMS AND METHODS: This mixed design experiment with study product (between-subjects) and patch (within-subjects) factors recruited adults smoking cigarettes daily and not motivated to quit (N = 160). Participants were randomized to 4 weeks of: (1) VLNCs; (2) e-cigarettes; or (3) no product. During two switch weeks, one with an active nicotine patch and one with a placebo patch (in a double-blind and counterbalanced fashion), participants were told to not smoke their usual cigarettes. RESULTS: During the switch weeks, participants in the VLNC (M = 2.88, SD = .65) and e-cigarette (M = 3.20, SD = .63) groups smoked fewer of their own cigarettes per day than did no product group participants who continued to smoke their own cigarettes (M = 5.48, SD = .63); the VLNC and e-cigarette groups did not differ. There was no main effect of patch on mean usual brand cigarettes smoked per day (P = .09), nor was there a product × patch interaction (P = .51). There was a product × age interaction (P = .03); smokers aged 60-74 smoked more of their own cigarettes if they were randomized to no product group. CONCLUSIONS: VLNCs and e-cigarettes appear to reduce usual brand cigarettes smoked per day to a similar degree, regardless of patch condition. Behavioral factors, in addition to nicotine dependence, play an important role in sustaining smoking behavior and need to be addressed in smoking cessation treatment. IMPLICATIONS: This study found that behavioral substitutes for cigarettes, whether or not they delivered nicotine, reduced the number of usual brand cigarettes smoked. Specifically, both e-cigarettes delivering nicotine and VLNCs equally reduce usual brand cigarettes smoked among adults who smoke daily and do not want to quit.

A Multicomponent Fall Prevention Strategy Reduces Falls at an Academic Medical Center.

BACKGROUND: While the reduction in fall rates has not kept pace with the reduction of other hospital-acquired conditions, patient safety research and quality improvement (QI) initiatives at the system and hospital levels have achieved positive results and provide insights into potentially effective risk reduction strategies. An academic medical center developed a QI-based multicomponent strategy for fall prevention and pilot tested it for six months in three high-risk units-the Neuroscience Acute Care Unit, the Myelosuppression/Stem Cell Transplant Unit, and the Acute Care for the Elderly Unit-before implementing and evaluating the strategy hospitalwide. METHODS: The multicomponent fall strategy was evaluated using a pre-post study design. The main outcome measures were falls and falls with harm measured in events per 1,000 patient-days. Fall rates were monitored and compared for three classes of falls: (1) accidental, (2) anticipated physiologic, and (3) unanticipated physiologic. RESULTS: Statistical process control charts showed that the pilot units had achieved significant reductions in falls with harm during the last five months of data collection. Wald test and segmented regression analyses revealed significant improvements in pooled postintervention fall rates, stratified by fall type. The hospitalwide implementation of the program resulted in a 47% overall reduction in falls in the postintervention period. CONCLUSION: A fall prevention strategy that targeted the spectrum of risk factors produced measurable improvement in fall rates and rates of patient harm. Hospitals must continue developing, rigorously testing, and sharing their results and experiences in implementing and sustaining multicomponent fall prevention strategies.

Complex Genomic Rearrangements following Selection in a Glutamine-Limited Medium over Hundreds of Generations.

Large-scale genomic changes, including copy number variations (CNVs), are frequently observed in long-term evolution experiments (LTEEs). We have previously reported the detection of recurrent CNVs in Saccharomyces cerevisiae populations adapting to glutamine-limited conditions over hundreds of generations. Here, we present the whole-genome sequencing (WGS) assemblies of 7 LTEE strains and their ancestor.

Fragment-based discovery of mexiletine derivatives as orally bioavailable inhibitors of urokinase-type plasminogen activator.

Fragment-based lead discovery has been applied to urokinase-type plasminogen activator (uPA). The (R)-enantiomer of the orally active drug mexiletine 5 (a fragment hit from X-ray crystallographic screening) was the chemical starting point. Structure-aided design led to elaborated inhibitors that retained the key interactions of (R)-5 while gaining extra potency by simultaneously occupying neighboring regions of the active site. Subsequent optimization led to 15, a potent, selective, and orally bioavailable inhibitor of uPA.

The impact of a brief interclerkship about substance abuse on medical students' skills.

PURPOSE: To examine the immediate and delayed impact of an intensive one- or two-day interclerkship on substance abuse (SA) for third-year medical students. The program is a response to the problem of inadequacy of substance abuse education in the standard curriculum. METHOD: Each year since 1997-98 all third-year students at the University of Massachusetts Medical School have participated in a one- or two-day SA interclerkship to enhance their knowledge and competence with SA assessment and brief intervention. Students' knowledge, attitudes, and confidence were assessed immediately before and after the interclerkship. In addition, during 1998-99, each student's clinical skills in SA assessment and intervention were evaluated at the completion of the student's six-week psychiatry clerkship using objective standardized clinical examinations (OSCEs) with two simulated patients, one with and one without active SA issues. Students who took the psychiatry clerkship in the first half of the year had not yet participated in the interclerkship. Students' pooled performances before and after the interclerkship were compared. RESULTS: Students' attitudes toward and knowledge about SA disorders and their confidence about SA assessment and intervention all showed significant positive changes immediately after the interclerkship. The OSCE performance data demonstrated a significant sustained improvement in clinical skills in SA assessment and intervention as measured up to six months following the interclerkship. CONCLUSION: These data suggest that brief intensive training in SA during the clinical years of medical school can have a positive and lasting impact on students' clinical performances.

Fragment-based discovery of the pyrazol-4-yl urea (AT9283), a multitargeted kinase inhibitor with potent aurora kinase activity.

Here, we describe the identification of a clinical candidate via structure-based optimization of a ligand efficient pyrazole-benzimidazole fragment. Aurora kinases play a key role in the regulation of mitosis and in recent years have become attractive targets for the treatment of cancer. X-ray crystallographic structures were generated using a novel soakable form of Aurora A and were used to drive the optimization toward potent (IC(50) approximately 3 nM) dual Aurora A/Aurora B inhibitors. These compounds inhibited growth and survival of HCT116 cells and produced the polyploid cellular phenotype typically associated with Aurora B kinase inhibition. Optimization of cellular activity and physicochemical properties ultimately led to the identification of compound 16 (AT9283). In addition to Aurora A and Aurora B, compound 16 was also found to inhibit a number of other kinases including JAK2 and Abl (T315I). This compound demonstrated in vivo efficacy in mouse xenograft models and is currently under evaluation in phase I clinical trials.