A genetic risk score based on direct associations with coronary heart disease improves coronary heart disease risk prediction in the Atherosclerosis Risk in Communities (ARIC), but not in the Rotterdam and Framingham Offspring, Studies

ObjectiveMultiple studies have identified single-nucleotide polymorphisms (SNPs) that are associated with coronary heart disease (CHD). We examined whether SNPs selected based on predefined criteria will improve CHD risk prediction when added to traditional risk factors (TRFs).MethodsSNPs were selected from the literature based on association with CHD, lack of association with a known CHD risk factor, and successful replication. A genetic risk score (GRS) was constructed based on these SNPs. Cox proportional hazards model was used to calculate CHD risk based on the Atherosclerosis Risk in Communities (ARIC) and Framingham CHD risk scores with and without the GRS.ResultsThe GRS was associated with risk for CHD (hazard ratio [HR] = 1.10; 95% confidence interval [CI]: 1.07–1.13). Addition of the GRS to the ARIC risk score significantly improved discrimination, reclassification, and calibration beyond that afforded by TRFs alone in non-Hispanic whites in the ARIC study. The area under the receiver operating characteristic curve (AUC) increased from 0.742 to 0.749 (Δ = 0.007; 95% CI, 0.004–0.013), and the net reclassification index (NRI) was 6.3%. Although the risk estimates for CHD in the Framingham Offspring (HR = 1.12; 95% CI: 1.10–1.14) and Rotterdam (HR = 1.08; 95% CI: 1.02–1.14) Studies were significantly improved by adding the GRS to TRFs, improvements in AUC and NRI were modest.ConclusionAddition of a GRS based on direct associations with CHD to TRFs significantly improved discrimination and reclassification in white participants of the ARIC Study, with no significant improvement in the Rotterdam and Framingham Offspring Studies.     

Staphylococcal pathogenicity island interference with helper phage reproduction is a paradigm of molecular parasitism

Staphylococcal pathogenicity islands (SaPIs) carry superantigen and resistance genes and are extremely widespread in Staphylococcus aureus and in other Gram-positive bacteria. SaPIs represent a major source of intrageneric horizontal gene transfer and a stealth conduit for intergeneric gene transfer; they are phage satellites that exploit the life cycle of their temperate helper phages with elegant precision to enable their rapid replication and promiscuous spread. SaPIs also interfere with helper phage reproduction, blocking plaque formation, sharply reducing burst size and enhancing the survival of host cells following phage infection. Here, we show that SaPIs use several different strategies for phage interference, presumably the result of convergent evolution. One strategy, not described previously in the bacteriophage microcosm, involves a SaPI-encoded protein that directly and specifically interferes with phage DNA packaging by blocking the phage terminase small subunit. Another strategy involves interference with phage reproduction by diversion of the vast majority of virion proteins to the formation of SaPI-specific small infectious particles. Several SaPIs use both of these strategies, and at least one uses neither but possesses a third. Our studies illuminate a key feature of the evolutionary strategy of these mobile genetic elements, in addition to their carriage of important genes—interference with helper phage reproduction, which could ensure their transferability and long-term persistence.     

Age and distraction are determinants of performance on a novel visual search task in aged Beagle dogs

Aging has been shown to disrupt performance on tasks that require intact visual search and discrimination abilities in human studies. The goal of the present study was to determine if canines show age-related decline in their ability to perform a novel simultaneous visual search task. Three groups of canines were included: a young group (N = 10; 3 to 4.5 years), an old group (N = 10; 8 to 9.5 years), and a senior group (N = 8; 11 to 15.3 years). Subjects were first tested for their ability to learn a simple two-choice discrimination task, followed by the visual search task. Attentional demands in the task were manipulated by varying the number of distracter items; dogs received an equal number of trials with either zero, one, two, or three distracters. Performance on the two-choice discrimination task varied with age, with senior canines making significantly more errors than the young. Performance accuracy on the visual search task also varied with age; senior animals were significantly impaired compared to both the young and old, and old canines were intermediate in performance between young and senior. Accuracy decreased significantly with added distracters in all age groups. These results suggest that aging impairs the ability of canines to discriminate between task-relevant and -irrelevant stimuli. This is likely to be derived from impairments in cognitive domains such as visual memory and learning and selective attention.     

Outcomes of preoperative Angiotensin-converting enzyme inhibitor therapy in patients undergoing isolated coronary artery bypass grafting

The association between preoperative use of angiotensin-converting enzyme (ACE) inhibitors and outcomes after coronary artery bypass grafting (CABG) remain controversial. Our aim was to study in-hospital outcomes after isolated CABG in patients on preoperative ACE inhibitors. A retrospective analysis of 8,889 patients who underwent isolated CABG from 2000 through 2011 was conducted. The primary outcome of interest was the incidence of major adverse events (MAEs) defined as a composite of mortality, postoperative renal dysfunction, myocardial infarction, stroke, and atrial fibrillation during index hospitalization. The secondary outcome was the incidence of individual outcomes included in MAEs. Logistic regression analyses were performed. Of 8,889 patients, 3,983 (45%) were on preoperative ACE inhibitors and 4,906 (55%) were not. Overall incidence of MAEs was 38.1% (n = 1,518) in the ACE inhibitor group compared to 33.6% (n = 1,649) in the no-ACE inhibitor group. Preoperative use of ACE inhibitors was independently associated with MAEs (odds ratio 1.13, 95% confidence interval 1.03 to 1.24), most of which was driven by a statistically significant increase in postoperative renal dysfunction (odds ratio 1.18, 95% confidence interval 1.03 to 1.36) and atrial fibrillation (odds ratio 1.15, 95% confidence interval 1.05 to 1.27). In-hospital mortality, postoperative myocardial infarction, and stroke were not significantly associated with preoperative ACE inhibitor use. Analyses performed after excluding patients with low ejection fractions yielded similar results. In conclusion, preoperative ACE inhibitor use was associated with an increased risk of MAEs after CABG, in particular postoperative renal dysfunction and atrial fibrillation.     

A 137‐kb deletion within the Potocki–Shaffer syndrome interval on chromosome 11p11.2 associated with developmental delay and hypotonia

Potocki–Shaffer syndrome (PSS) is a rare disorder caused by haploinsufficiency of genes located on the proximal short arm of chromosome 11 (11p11.2p12). Classic features include biparietal foramina, multiple exostoses, profound hypotonia, dysmorphic features, and developmental delay/intellectual disability. Fewer than 40 individuals with PSS have been reported, with variable clinical presentations due in part to disparity in deletion sizes. We report on a boy who presented for initial evaluation at age 13 months because of a history of developmental delay, hypotonia, subtle dysmorphic features, and neurobehavioral abnormalities. SNP microarray analysis identified a 137 kb deletion at 11p11.2, which maps within the classically defined PSS interval. This deletion results in haploinsufficiency for all or portions of six OMIM genes: SLC35C1, CRY2, MAPK8IP1, PEX16, GYLTL1B, and PHF21A. Recently, translocations interrupting PHF21A have been associated with intellectual disability and craniofacial anomalies similar to those seen in PSS. The identification of this small deletion in a child with developmental delay and hypotonia provides further evidence for the genetic basis of developmental disability and identifies a critical region sufficient to cause hypotonia in this syndrome. Additionally, this case illustrates the utility of high resolution genomic approaches in correlating clinical phenotypes with specific genes in contiguous gene deletion syndromes. © 2012 Wiley Periodicals, Inc.     

ApoA-I Induction as a Potential Cardioprotective Strategy: Rationale for the SUSTAIN and ASSURE Studies

Background  

Considerable interest has focused on the development of therapies that target the functionality of high-density lipoproteins (HDL). Upregulation of endogenous synthesis of the major protein on HDL particles, apolipoprotein A-I (apoA-I), represents a novel approach to generation of new HDL particles. The Study of Quantitative Serial Trends in Lipids with Apolipoprotein A-I Stimulation (SUSTAIN, NCT01423188) study aims to evaluate the lipid efficacy, safety and tolerability of an apoA-I inducer (RVX-208). The ApoA-I Synthesis Stimulation and Intravascular Ultrasound for Coronary Atheroma Regression Evaluation (ASSURE, NCT01067820) study aims to evaluate the effect of RVX-208 on plaque burden.