In vivo diffusion tensor MRI of the human heart: Reproducibility of breath‐hold and navigator‐based approaches

The aim of this study was to implement a quantitative in vivo cardiac diffusion tensor imaging (DTI) technique that was robust, reproducible, and feasible to perform in patients with cardiovascular disease. A stimulated‐echo single‐shot echo‐planar imaging (EPI) sequence with zonal excitation and parallel imaging was implemented, together with a novel modification of the prospective navigator (NAV) technique combined with a biofeedback mechanism. Ten volunteers were scanned on two different days, each time with both multiple breath‐hold (MBH) and NAV multislice protocols. Fractional anisotropy (FA), mean diffusivity (MD), and helix angle (HA) fiber maps were created. Comparison of initial and repeat scans showed good reproducibility for both MBH and NAV techniques for FA (P > 0.22), MD (P > 0.15), and HA (P > 0.28). Comparison of MBH and NAV FA (FA_MBHday1 = 0.60 ± 0.04, FA_NAVday1 = 0.60 ± 0.03, P = 0.57) and MD (MD_MBHday1 = 0.8 ± 0.2 × 10^?3 mm²/s, MD_NAVday1 = 0.9 ± 0.2 × 10^?3 mm²/s, P = 0.07) values showed no significant differences, while HA values (HA_MBHday1Endo = 22 ± 10°, HA_{MBHday1Mid‐Endo} = 20 ± 6°, HA_{MBHday1Mid‐Epi} = ?1 ± 6°, HA_MBHday1Epi = ?17 ± 6°, HA_NAVday1Endo = 7 ± 7°, HA_{NAVday1Mid‐Endo} = 13 ± 8°, HA_{NAVday1Mid‐Epi} = ?2 ± 7°, HA_NAVday1Epi = ?14 ± 6°) were significantly different. The scan duration was 20% longer with the NAV approach. Currently, the MBH approach is the more robust in normal volunteers. While the NAV technique still requires resolution of some bulk motion sensitivity issues, these preliminary experiments show its potential for in vivo clinical cardiac diffusion tensor imaging and for delivering high‐resolution in vivo 3D DTI tractography of the heart. Magn Reson Med 70:454–465, 2013. © 2012 Wiley Periodicals, Inc.     

The synergistic effects of insecticidal essential oils and piperonyl butoxide on biotransformational enzyme activities in Aedes aegypti (Diptera: Culicidae)

The biochemical mechanisms underlying the increased toxicity of several plant essential oils (thymol, eugenol, pulegone, terpineol, and citronellal) against fourth instar of Aedes aegypti L. when exposed simultaneously with piperonyl butoxide (PBO) were examined. Whole body biotransformational enzyme activities including cytochrome P450-mediated oxidation (ethoxyresorufin O-dethylase [EROD]), glutathione S-transferase (GST), and beta-esterase activity were measured in control, essential oil-exposed only (single chemical), and essential oil + PBO (10 mg/liter) exposed larvae. At high concentrations, thymol, eugenol, pulegone, and citronellal alone reduced EROD activity by 5-25% 16 h postexposure. Terpineol at 10 mg/liter increased EROD activity by 5 +/- 1.8% over controls. The essential oils alone reduced GST activity by 3-20% but PBO exposure alone did not significantly affect the activity of any of the measured enzymes. All essential oils in combination with PBO reduced EROD activity by 58-76% and reduced GST activity by 3-85% at 16 h postexposure. This study indicates a synergistic interaction between essential oils and PBO in inhibiting the cytochrome P450 and GST detoxification enzymes in Ae. aegypti.     

Real-time MRI guided atrial septal puncture and balloon septostomy in swine.

Cardiac perforation during atrial septal puncture (ASP) might be avoided by improved image guidance. X-ray fluoroscopy (XRF), which guides ASP, visualizes tissue poorly and does not convey depth information. Ultrasound is limited by device shadows and constrained imaging windows. Alternatively, real-time MRI (rtMRI) provides excellent tissue contrast in any orientation and may enable ASP and balloon atrial septostomy (BAS) in swine. Custom MRI catheters incorporated "active" (receiver antenna) and "passive" (iron or gadolinium) elements. Wholly rtMRI-guided transfemoral ASP and BAS were performed in 10 swine in a 1.5T interventional suite. Hemodynamic results were measured with catheters and velocity encoded MRI. Successful ASP was performed in all 10 animals. Necropsy confirmed septostomy confined within the fossa ovalis in all. BAS was successful in 9/10 animals. Antenna failure in a re-used needle led to inadvertent vena cava tear prior to BAS in 1 animal. ASP in the same animal was easily performed using a new needle. rtMRI illustrated clear device-tissue-lumen relationships in multiple orientations, and facilitated simple ASP and BAS. The mean procedure time was 19 +/- 10 minutes. Septostomy achieved a mean left to right shunt ratio of 1.3:1 in these healthy animals. Interactive rtMRI permits rapid transcatheter ASP and BAS in swine. Further technical development may enable novel applications.     

Psychological autopsy study of suicide in three rural and semi-rural districts of Sri Lanka

BACKGROUND: Knowledge concerning the epidemiology of suicide in Sri Lanka is limited despite its suicide rates being amongst the highest in the world. AIM: To examine the characteristics of a large sample of Sri Lankan suicides to inform approaches to prevention. METHOD: Psychological autopsy study of suicides occurring in three rural districts of Sri Lanka during August-October 1997. RESULTS: Interviews were conducted with contacts of 372 (74%) of the 499 suicides that occurred over the study period. Males accounted for 79% of the deaths. Twenty-one percent of male and 57% of female suicides were aged <25 years of age. Pesticide self-poisoning accounted for 259 (70%) of the deaths. Almost two-thirds (62%) of the deaths occurred in hospital and 95 (26%) had made previous suicidal gestures. 138 (37%) were moderately or severely depressed and 144 (49%) of male suicides, but only 2 (2.5%) of the females, were alcohol dependent. Illegally brewed alcohol (kasippu) was the main product used by two thirds (62%) of problem drinkers. There was a family history of suicide in 20% of cases. CONCLUSION: Pesticide self-poisoning accounts for over two thirds of suicides in rural Sri Lanka. Suicide prevention efforts in Sri Lanka should focus on restricting access to pesticides, improving the medical management of pesticide poisoning, reducing alcohol misuse-particularly targeting the supply of illegal alcohol-and improving the identification and aftercare of people who self-harm.     

Interventional cardiovascular procedures guided by real-time MR imaging: an interactive interface using multiple slices, adaptive projection modes and live 3D renderings

PURPOSE: To develop and test a novel interactive real-time MRI environment that facilitates image-guided cardiovascular interventions. MATERIALS AND METHODS: Color highlighting of device-mounted receiver coils, accelerated imaging of multiple slices, adaptive projection modes, live three-dimensional (3D) renderings and other interactive features were utilized to enhance navigation of devices and targeting of tissue. RESULTS: Images are shown from several catheter-based interventional procedures performed in swine that benefit from this custom interventional MRI interface. These include endograft repair of aortic aneurysm, balloon septostomy of the cardiac interatrial septum, angioplasty and stenting, and endomyocardial cell injection, all using active catheters containing MRI receiver coils. CONCLUSION: Interactive features not available on standard clinical scanners enhance real-time MRI for guiding cardiovascular interventional procedures.     

Prevalence,Trends and Associated Socio-Economic Factors of Obesity in South Asia

AimWorldwide obesity levels have increased unprecedentedly over the past couple of decades. Although the prevalence, trends and associated socio-economic factors of the condition have been extensively reported in Western populations, less is known regarding South Asian populations.MethodsA review of articles using Medline with combinations of the MeSH terms: ‘Obesity’, ‘Overweight’ and ‘Abdominal Obesity’ limiting to epidemiology and South Asian countries.ResultsDespite methodological heterogeneity and variation according to country, area of residence and gender, the most recent nationally representative and large regional data demonstrates that without any doubt there is a epidemic of obesity, overweight and abdominal obesity in South Asian countries. Prevalence estimates of overweight and obesity (based on Asian cut-offs: overweight ≥ 23 kg/m², obesity ≥ 25 kg/m²) ranged from 3.5% in rural Bangladesh to over 65% in the Maldives. Abdominal obesity was more prevalent than general obesity in both sexes in this ethnic group. Countries with the lowest prevalence had the highest upward trend of obesity. Socio-economic factors associated with greater obesity in the region included female gender, middle age, urban residence, higher educational and economic status.ConclusionSouth Asia is significantly affected by the obesity epidemic. Collaborative public health interventions to reverse these trends need to be mindful of many socio-economic constraints in order to provide long-term solutions.Key Words: Obesity, Socio-economic factors, Prevalence, Trend, South Asia