Spectroscopy of Bright QUEST RR Lyrae Stars: Velocity Substructures toward Virgo

Using a sample of 43 bright (V<16.1, distance <13 kpc) RR Lyrae stars (RRLS) from the QUEST survey with spectroscopic radial velocities and metallicities, we find that several separate halo substructures contribute to the Virgo overdensity (VOD). While there is little evidence for halo substructure in the spatial distribution of these stars, their distribution in radial velocity reveals two moving groups. These results are reinforced when the sample is combined with a sample of blue horizontal branch stars that were identified in the SDSS, and the combined sample provides evidence for one additional moving group. These groups correspond to peaks in the radial velocity distribution of a sample of F type main-sequence stars that was recently observed in the same directon by SEGUE, although in one case the RRLS and F star groups may not lie at the same distance. One of the new substructures has a very narrow range in metallicity, which is more consistent with it being the debris from a destroyed globular cluster than from a dwarf galaxy. A small concentration of stars have radial velocities that are similar to the Virgo Stellar Stream (VSS) that was identified previously in a fainter sample of RRLS. Our results suggest that this feature extends to distances as short as ~12 kpc from its previous detection at ~19 kpc. None of the new groups and only one star in the sample have velocities that are consistent with membership in the leading tidal stream from the Sagittarius Dwarf Spheroidal Galaxy, which some authors have suggested is the origin of the VOD.Comment: Accepted for publication in the A

Multidisciplinary pediatric trauma team training using high-fidelity trauma simulation

Abstract Background: Trauma resuscitations require a high level of team performance. This study evaluated the impact of a comprehensive effort to improve trauma care through multidisciplinary education and the use of simulation training to reinforce training and evaluate performance. Methods: For a 1-year period, expanded trauma education including monthly trauma simulation sessions using high-fidelity simulators was implemented. All members of the multidisciplinary trauma resuscitation team participated in education, including simulations. Each simulation session included 2 trauma scenarios that were videotaped for debriefing as well as subsequent analysis of team performance. Scored simulations were divided into early (initial 4 months) and late (final 4 months) for comparison. Results: For the first year of the program, 160 members of our multidisciplinary team participated in the simulation. In the early group, the mean percentage of appropriately completed tasks was 65%, whereas in the late group, this increased to 75% (P b .05). Improvements were also observed in initial assessment, airway management, management of pelvic fractures, and cervical spine care. Conclusions: Training of a multidisciplinary team in the care of pediatric trauma patients can be enhanced and evaluated through the use of high-fidelity simulation. Improvements in team performance using innovative technology can translate into more efficient care with fewer errors

Clinical clearance of the cervical spine in blunt trauma patients younger than 3 years: A multi-center study of the American association for the surgery of trauma

Background: Cervical spine clearance in the very young child is challenging. Radiographic imaging to diagnose cervical spine injuries (CSI) even in the absence of clinical findings is common, raising concerns about radiation exposure and imaging-related complications. We examined whether simple clinical criteria can be used to safely rule out CSI in patients younger than 3 years.Methods: The trauma registries from 22 level I or II trauma centers were reviewed for the 10-year period (January 1995 to January 2005). Blunt trauma patients younger than 3 years were identified. The measured outcome was CSI. Independent predictors of CSI were identified by univariate and multivariate analysis. A weighted score was calculated by assigning 1, 2, or 3 points to each independent predictor according to its magnitude of effect. The score was established on two thirds of the population and validated using the remaining one third.Results: Of 12,537 patients younger than 3 years, CSI was identified in 83 patients (0.66%), eight had spinal cord injury. Four independent predictors of CSI were identified: Glasgow Coma Score \u3c14, GCSEYE = 1, motor vehicle crash, and age 2 years or older. A score of \u3c2 had a negative predictive value of 99.93% in ruling out CSI. A total of 8,707 patients (69.5% of all patients) had a score of \u3c2 and were eligible for cervical spine clearance without imaging. There were no missed CSI in this study.Conclusions: CSI in patients younger than 3 years is uncommon. Four simple clinical predictors can be used in conjunction to the physical examination to substantially reduce the use of radiographic imaging in this patient population

Laparotomy versus peritoneal drainage for necrotizing enterocolitis and perforation

Background: Perforated necrotizing enterocolitis is a major cause of morbidity and mortality in premature infants, and the optimal treatment is uncertain. We designed this multicenter randomized trial to compare outcomes of primary peritoneal drainage with laparotomy and bowel resection in preterm infants with perforated necrotizing enterocolitis.Methods: We randomly assigned 117 preterm infants (delivered before 34 weeks of gestation) with birth weights less than 1500 g and perforated necrotizing enterocolitis at 15 pediatric centers to undergo primary peritoneal drainage or laparotomy with bowel resection. Postoperative care was standardized. The primary outcome was survival at 90 days postoperatively. Secondary outcomes included dependence on parenteral nutrition 90 days postoperatively and length of hospital stay.Results: At 90 days postoperatively, 19 of 55 infants assigned to primary peritoneal drainage had died (34.5 percent), as compared with 22 of 62 infants assigned to laparotomy (35.5 percent, P=0.92). The percentages of infants who depended on total parenteral nutrition were 17 of 36 (47.2 percent) in the peritoneal-drainage group and 16 of 40 (40.0 percent) in the laparotomy group (P=0.53). The mean (+/-SD) length of hospitalization for the 76 infants who were alive 90 days after operation was similar in the primary peritoneal-drainage and laparotomy groups (126+/-58 days and 116+/-56 days, respectively; P=0.43). Subgroup analyses stratified according to the presence or absence of radiographic evidence of extensive necrotizing enterocolitis (pneumatosis intestinalis), gestational age of less than 25 weeks, and serum pH less than 7.30 at presentation showed no significant advantage of either treatment in any group.Conclusions: The type of operation performed for perforated necrotizing enterocolitis does not influence survival or other clinically important early outcomes in preterm infants. (ClinicalTrials.gov number, NCT00252681.)

A Cross-sectional Study of the Association Between Chronic Hepatitis C Virus Infection and Subclinical Coronary Atherosclerosis Among Participants in the Multicenter AIDS Cohort Study

BackgroundHepatitis C virus (HCV) infection may increase the risk of cardiovascular disease (CVD). We evaluated the association of chronic HCV infection and coronary atherosclerosis among participants in the Multicenter AIDS Cohort Study.MethodsWe assessed 994 men with or without human immunodeficiency virus (HIV) infection (87 of whom had chronic HCV infection) for coronary plaque, using noncontrast coronary computed tomography (CT); 755 also underwent CT angiography. We then evaluated the associations of chronic HCV infection and HIV infection with measures of plaque prevalence, extent, and stenosis.ResultsAfter adjustment for demographic characteristics, HIV serostatus, behaviors, and CVD risk factors, chronic HCV infection was significantly associated with a higher prevalence of coronary artery calcium (prevalence ratio, 1.29; 95% confidence interval [CI], 1.02-1.63), any plaque (prevalence ratio, 1.26; 95% CI, 1.09-1.45), and noncalcified plaque (prevalence ratio, 1.42; 95% CI, 1.16-1.75). Chronic HCV infection and HIV infection were independently associated with the prevalence of any plaque and of noncalcified plaque, but there was no evidence of a synergistic effect due to HIV/HCV coinfection. The prevalences of coronary artery calcium, any plaque, noncalcified plaque, a mixture of noncalcified and calcified plaque, and calcified plaque were significantly higher among men with an HCV RNA load of ≥2 × 10(6) IU/mL, compared with findings among men without chronic HCV infection.ConclusionsChronic HCV infection is associated with subclinical CVD, suggesting that vigilant assessments of cardiovascular risk are warranted for HCV-infected individuals. Future research should determine whether HCV infection duration or HCV treatment influence coronary plaque development

A Cross-sectional Study of the Association Between Chronic Hepatitis C Virus Infection and Subclinical Coronary Atherosclerosis Among Participants in the Multicenter AIDS Cohort Study

Background. Hepatitis C virus (HCV) infection may increase the risk of cardiovascular disease (CVD). We evaluated the association of chronic HCV infection and coronary atherosclerosis among participants in the Multicenter AIDS Cohort Study. Methods. We assessed 994 men with or without human immunodeficiency virus (HIV) infection (87 of whom had chronic HCV infection) for coronary plaque, using noncontrast coronary computed tomography (CT); 755 also underwent CT angiography. We then evaluated the associations of chronic HCV infection and HIV infection with measures of plaque prevalence, extent, and stenosis. Results. After adjustment for demographic characteristics, HIV serostatus, behaviors, and CVD risk factors, chronic HCV infection was significantly associated with a higher prevalence of coronary artery calcium (prevalence ratio, 1.29; 95% confidence interval [CI], 1.02–1.63), any plaque (prevalence ratio, 1.26; 95% CI, 1.09–1.45), and noncalcified plaque (prevalence ratio, 1.42; 95% CI, 1.16–1.75). Chronic HCV infection and HIV infection were independently associated with the prevalence of any plaque and of noncalcified plaque, but there was no evidence of a synergistic effect due to HIV/HCV coinfection. The prevalences of coronary artery calcium, any plaque, noncalcified plaque, a mixture of noncalcified and calcified plaque, and calcified plaque were significantly higher among men with an HCV RNA load of ≥2 × 10(6) IU/mL, compared with findings among men without chronic HCV infection. Conclusions. Chronic HCV infection is associated with subclinical CVD, suggesting that vigilant assessments of cardiovascular risk are warranted for HCV-infected individuals. Future research should determine whether HCV infection duration or HCV treatment influence coronary plaque development

Occult RV systolic dysfunction detected by CMR derived RV circumferential strain in patients with pectus excavatum

<div><p>Aims</p><p>To investigate the right ventricular (RV) strain in pectus excavatum (PE) patients using cardiac magnetic resonance tissue tracking (CMR TT).</p><p>Materials and methods</p><p>Fifty consecutive pectus excavatum patients, 10 to 32 years of age (mean age 15 ± 4 years), underwent routine cardiac magnetic resonance imaging (CMR) including standard measures of chest geometry and cardiac size and function. The control group consisted of 20 healthy patients with a mean age of 17 ± 5 years. RV longitudinal and circumferential strain magnitude was assessed by a dedicated RV tissue tracking software.</p><p>Results</p><p>Fifty patients with images of sufficient quality were included in the analysis. The mean right and left ventricular ejection fractions were 55 ± 5% and 59 ± 4%. The RV global longitudinal strain was -21.88 ± 4.63%. The RV circumferential strain at base, mid-cavity and apex were -13.66 ± 3.09%, -11.31 ± 2.79%, -20.73 ± 3.45%, respectively. There was no statistically significant decrease in right ventricular or left ventricular ejection fraction between patients and controls (p > 0.05 for each). There was no significant difference in RV global longitudinal strain between two groups (-21.88 ± 4.63 versus -21.99 ± 3.58; <i>p</i> = 0.93). However, there was significant decrease in mid-cavity circumferential strain magnitude in pectus patients compared with controls (-11.31 ± 2.79 versus -16.19 ± 2.86; <i>p</i> < 0.001). PE patients had a significantly higher basal circumferential strain (-13.66 ± 3.09% versus -9.76 ± 1.79; <i>p</i> < 0.001) as well as apical circumferential strain (-20.73 ± 3.45% versus -12.07 ± 3.38) than control group.</p><p>Conclusion</p><p>Mid-cavity circumferential strain but not longitudinal strain is reduced in pectus excavatum patients. Basal circumferential strain as well as apical circumferential strain were increased as compensatory mechanism for reduced mid-cavity circumferential strain. Further studies are needed to establish clinical significance of this finding.</p></div

Chest index.

<p>Chest index.</p

Relationship between pectus severity index and right ventricular ejection fraction, myocardial strain.

<p>Relationship between pectus severity index and right ventricular ejection fraction, myocardial strain.</p

Pectus index and CMR tissue tracking.

<p>(A) The Haller Index (HI) is a ratio of the transverse diameter of the chest (line a) to the distance between the posterior aspect of the sternum and the anterior portion of the vertebra (line b): HI = a/b. The correction index (CI) measures the depression of the sternum relative to the anterior chest: CI = [(c-b)/c] x 100. (B) Right ventricular longitudinal strain. (C) and (D) Mid-cavity circumferential strain and peak value was recorded. The yellow colored contours show the tracking of the ventricle.</p