Heart ablation using a planar rectangular high intensity ultrasound transducer and MRI guidance

The aim of this study was to evaluate a flat rectangular (3 × 10 mm2) MRI compatible transducer operating at 5 MHz. The main task was to explore the feasibility of creating deep lesions in heart at a depth of at least 15 mm. The size of thermal necrosis in heart tissue was estimated as a function of power and time using a simulation model. The system was then tested in an excised lamb heart. In this study, we were able to create lesions of 15 mm deep with acoustic power of 6 W for an exposure of approximately 1 min. The contrast to noise ratio (CNR) between lesion and heart tissue was evaluated using fast spin echo (FSE). The CNR value was approximately 22 using T1 W FSE. Maximum CNR was achieved with repetition time (TR) between 300 and 800 ms. Using T2W FSE, the corresponding CNR was approximately 13 for the 14 in vivo experiments. The average lesion depth was 11.93 mm with a standard deviation of 0.62 mm. In vivo irradiation conditions were 6 W for 60 s. The size of the lesion in the other two dimensions was close to 3 × 10 mm2 (size of the transducer element)

The Distribution of Bar and Spiral Strengths in Disk Galaxies

The distribution of bar strengths in disk galaxies is a fundamental property of the galaxy population that has only begun to be explored. We have applied the bar/spiral separation method of Buta, Block, and Knapen to derive the distribution of maximum relative gravitational bar torques, Q_b, for 147 spiral galaxies in the statistically well-defined Ohio State University Bright Galaxy Survey (OSUBGS) sample. Our goal is to examine the properties of bars as independently as possible of their associated spirals. We find that the distribution of bar strength declines smoothly with increasing Q_b, with more than 40% of the sample having Q_b <= 0.1. In the context of recurrent bar formation, this suggests that strongly-barred states are relatively short-lived compared to weakly-barred or non-barred states. We do not find compelling evidence for a bimodal distribution of bar strengths. Instead, the distribution is fairly smooth in the range 0.0 <= Q_b < 0.8. Our analysis also provides a first look at spiral strengths Q_s in the OSU sample, based on the same torque indicator. We are able to verify a possible weak correlation between Q_s and Q_b, in the sense that galaxies with the strongest bars tend also to have strong spirals.Comment: Accepted for publication in the Astronomical Journal, August 2005 issue (LaTex, 23 pages + 11 figures, uses aastex.cls

Globular cluster systems in elliptical galaxies of Coma

Globular cluster systems of 17 elliptical galaxies have been studied in the Coma cluster of galaxies. Surface-brightness fluctuations have been used to determine total populations of globular clusters and specific frequency (S_N) has been evaluated for each individual galaxy. Enormous differences in S_N between similar galaxies are found. In particular, S_N results vary by an order of magnitude from galaxy to galaxy. Extreme cases are the following: a) at the lower end of the range, NGC 4673 has S_N = 1.0 +/- 0.4, a surprising value for an elliptical galaxy, but typical for spiral and irregular galaxies; b) at the upper extreme, MCG +5 -31 -063 has S_N = 13.0 +/- 4.2 and IC 4051 S_N = 12.7 +/- 3.2, and are more likely to belong to supergiant cD galaxies than to "normal" elliptical galaxies. Furthermore, NGC 4874, the central supergiant cD galaxy of the Coma cluster, also exhibits a relatively high specific frequency (S_N = 9.0 +/- 2.2). The other galaxies studied have S_N in the range [2, 7], the mean value being S_N = 5.1. No single scenario seems to account for the observed specific frequencies, so the history of each galaxy must be deduced individually by suitably combining the different models (in situ, mergers, and accretions). The possibility that Coma is formed by several subgroups is also considered. If only the galaxies of the main subgroup defined by Gurzadyan & Mazure (2001) are used, a trend in S_N arises in the sense of S_N being bigger in higher density regions. This result needs further confirmation.Comment: 43 pages including 12 .ps figures, accepted for publication in Ap

Cross-sectional associations between air pollution and chronic bronchitis: an ESCAPE meta-analysis across five cohorts

BACKGROUND: This study aimed to assess associations of outdoor air pollution on prevalence of chronic bronchitis symptoms in adults in five cohort studies (Asthma-E3N, ECRHS, NSHD, SALIA, SAPALDIA) participating in the European Study of Cohorts for Air Pollution Effects (ESCAPE) project. METHODS: Annual average particulate matter (PM10, PM2.5, PMabsorbance, PMcoarse), NO2, nitrogen oxides (NOx) and road traffic measures modelled from ESCAPE measurement campaigns 2008-2011 were assigned to home address at most recent assessments (1998-2011). Symptoms examined were chronic bronchitis (cough and phlegm for &ge;3 months of the year for &ge;2 years), chronic cough (with/without phlegm) and chronic phlegm (with/without cough). Cohort-specific cross-sectional multivariable logistic regression analyses were conducted using common confounder sets (age, sex, smoking, interview season, education), followed by meta-analysis. RESULTS: 15 279 and 10 537 participants respectively were included in the main NO2 and PM analyses at assessments in 1998-2011. Overall, there were no statistically significant associations with any air pollutant or traffic exposure. Sensitivity analyses including in asthmatics only, females only or using back-extrapolated NO2 and PM10 for assessments in 1985-2002 (ECRHS, NSHD, SALIA, SAPALDIA) did not alter conclusions. In never-smokers, all associations were positive, but reached statistical significance only for chronic phlegm with PMcoarse OR 1.31 (1.05 to 1.64) per 5 &micro;g/m(3) increase and PM10 with similar effect size. Sensitivity analyses of older cohorts showed increased risk of chronic cough with PM2.5abs (black carbon) exposures. CONCLUSIONS: Results do not show consistent associations between chronic bronchitis symptoms and current traffic-related air pollution in adult European populations

Body silhouette, menstrual function at adolescence and breast cancer risk in the E3N cohort study

We analysed the relation between adult breast cancer risk and adiposity in ages 8–25, and among 90 509 women included in the E3N cohort study, and investigated the potential modification effect of certain factors. Participants completed a questionnaire that included a set of eight silhouettes corresponding to body shape at different ages. During the follow-up (mean=11.4 years), 3491 breast cancer cases were identified. Negative trends in risk of breast cancer with increasing body silhouettes at age 8 and at menarche were observed, irrespective of menopausal status, with relative risks of 0.73 (0.53–0.99) and 0.82 (0.66–1.02) for women who reported a silhouette equal or greater than the fifth silhouette at age 8 and at menarche, respectively. We observed no clear effect modification by age at menarche, delay between age at menarche, regular cycling, regularity of cycles in adult life or body mass index at baseline

Lifestyle, dietary factors and antibody levels to oral bacteria in cancer-free participants of a European cohort study

Background—Increasing evidence suggests that oral microbiota play a pivotal role in chronic diseases, in addition to the well-established role in periodontal disease. Moreover, recent studies suggest that oral bacteria may also be involved in carcinogenesis; periodontal disease has been linked several cancers. In this study, we examined whether lifestyle factors have an impact on antibody levels to oral bacteria. Methods—Data on demographic characteristics, lifestyle factors, and medical conditions were obtained at the time of blood sample collection. For the current analysis, we measured antibody levels to 25 oral bacteria in 395 cancer-free individuals using an immunoblot array. Combined total immunglobin G (IgG) levels were obtained by summing concentrations for all oral bacteria measured. Results—IgG antibody levels were substantially lower among current and former smokers (1697 and 1677 ng/mL, respectively) than never smokers (1960 ng/mL; p-trend = 0.01), but did not vary by other factors, including BMI, diabetes, physical activity, or by dietary factors, after adjusting for age, sex, education, country and smoking status. The highest levels of total IgG were found among individuals with low education (2419 ng/mL). Conclusions—Our findings on smoking are consistent with previous studies and support the notion that smokers have a compromised humoral immune response. Moreover, other major factors known to be associated with inflammatory markers, including obesity, were not associated with antibody levels to a large number of oral bacteria

Evolution of Galactic Discs: Multiple Patterns, Radial Migration and Disc Outskirts

We investigate the evolution of galactic disks in N-body Tree-SPH simulations. We find that disks, initially truncated at three scale-lengths, can triple their radial extent, solely driven by secular evolution. Both Type I (single exponential) and Type II (down-turning) observed disk surface-brightness profiles can be explained by our findings. We relate these results to the strong angular momentum outward transfer, resulting from torques and radial migration associated with multiple patterns, such as central bars and spiral waves of different multiplicity. We show that even for stars ending up on cold orbits, the changes in angular momentum exhibit complex structure as a function of radius, unlike the expected effect of transient spirals alone. Focussing on one of our models, we find evidence for non-linear coupling among m=1, 2, 3 and 4 density waves, where m is the pattern multiplicity. We suggest that the naturally occurring larger resonance widths at galactic radii beyond four scale-lengths may have profound consequences on the formation and location of breaks in disk density profiles, provided spirals are present at such large distances. We also consider the effect of gas inflow and show that when in-plane smooth gas accretion of ~5 M_sun/yr is included, the outer disks become more unstable, leading to a strong increase in the stellar velocity dispersion. This, in turn, causes the formation of a Type III (up-turning) profile in the old stellar population. We propose that observations of Type III surface brightness profiles, combined with an up-turn in the stellar velocity dispersions beyond the disk break, could be a signature of ongoing gas-accretion. The results of this study suggest that disk outskirts comprised of stars migrated from the inner disk would have relatively large radial velocity dispersions, and significant thickness when seen edge-on. [Abridged]Comment: Replaced with accepted version. New Fig. 5 added, Section 10 decreased in size, old Fig. 17 removed. Conclusions remain the same. High-resolution version can be found at http://www.ivanminchev.co

Predicting Diabetes: Clinical, Biological, and Genetic Approaches: Data from the Epidemiological Study on the Insulin Resistance Syndrome (DESIR)

OBJECTIVE—To provide a simple clinical diabetes risk score and to identify characteristics that predict later diabetes using variables available in the clinic setting as well as biological variables and polymorphisms

Intragenic ATM Methylation in Peripheral Blood DNA as a Biomarker of Breast Cancer Risk

Few studies have evaluated the association between DNA methylation in white blood cells (WBC) and the risk of breast cancer. The evaluation of WBC DNA methylation as a biomarker of cancer risk is of particular importance as peripheral blood is often available in prospective cohorts and easier to obtain than tumor or normal tissues. Here, we used prediagnostic blood samples from three studies to analyze WBC DNA methylation of two ATM intragenic loci (ATMmvp2a and ATMmvp2b) and genome-wide DNA methylation in long interspersed nuclear element-1 (LINE1) repetitive elements. Samples were from a case-control study derived from a cohort of high-risk breast cancer families (KConFab) and nested case-control studies in two prospective cohorts: Breakthrough Generations Study (BGS) and European Prospective Investigation into Cancer and Nutrition (EPIC). Bisulfite pyrosequencing was used to quantify methylation from 640 incident cases of invasive breast cancer and 741 controls. Quintile analyses for ATMmvp2a showed an increased risk of breast cancer limited to women in the highest quintile [OR, 1.89; 95% confidence interval (CI), 1.36-2.64; P = 1.64 x 10(-4)]. We found no significant differences in estimates across studies or in analyses stratified by family history or menopausal status. However, a more consistent association was observed in younger than in older women and individually significant in KConFab and BGS, but not EPIC. We observed no differences in LINE1 or ATMmvp2b methylation between cases and controls. Together, our findings indicate that WBC DNA methylation levels at ATM could be a marker of breast cancer risk and further support the pursuit of epigenome-wide association studies of peripheral blood DNA methylation. Cancer Res; 72(9); 2304-13. (C) 2012 AACR

A multi-stage genome-wide association study of bladder cancer identifies multiple susceptibility loci.

We conducted a multi-stage, genome-wide association study of bladder cancer with a primary scan of 591,637 SNPs in 3,532 affected individuals (cases) and 5,120 controls of European descent from five studies followed by a replication strategy, which included 8,382 cases and 48,275 controls from 16 studies. In a combined analysis, we identified three new regions associated with bladder cancer on chromosomes 22q13.1, 19q12 and 2q37.1: rs1014971, (P = 8 × 10⁻¹²) maps to a non-genic region of chromosome 22q13.1, rs8102137 (P = 2 × 10⁻¹¹) on 19q12 maps to CCNE1 and rs11892031 (P = 1 × 10⁻⁷) maps to the UGT1A cluster on 2q37.1. We confirmed four previously identified genome-wide associations on chromosomes 3q28, 4p16.3, 8q24.21 and 8q24.3, validated previous candidate associations for the GSTM1 deletion (P = 4 × 10⁻¹¹) and a tag SNP for NAT2 acetylation status (P = 4 × 10⁻¹¹), and found interactions with smoking in both regions. Our findings on common variants associated with bladder cancer risk should provide new insights into the mechanisms of carcinogenesis