John Radcliffe Hospital

About: John Radcliffe Hospital is a healthcare organization based out in Oxford, Oxfordshire, United Kingdom. It is known for research contribution in the topics: Population & Antigen. The organization has 14491 authors who have published 23670 publications receiving 1459015 citations.

Aortic dilation in bicuspid aortic valve disease: Flow pattern is a major contributor and differs with valve fusion type

Abstract: Background—Ascending aortic dilation is important in bicuspid aortic valve (BAV) disease, with increased risk of aortic dissection. We used cardiovascular MR to understand the pathophysiology better by examining the links between 3-dimensional flow abnormalities, aortic function, and aortic dilation. Methods and Results—A total of 142 subjects underwent cardiovascular MR (mean age, 40 years; 95 with BAV, 47 healthy volunteers). Patients with BAV had predominantly abnormal right-handed helical flow in the ascending aorta, larger ascending aortas (18.3±3.3 versus 15.2±2.2 mm/m 2 ; P<0.001), and higher rotational (helical) flow (31.7±15.8 versus 2.9±3.9 mm 2 /s; P<0.001), systolic flow angle (23.1°±12.5° versus 7.0°±4.6°; P<0.001), and systolic wall shear stress (0.85±0.28 versus 0.59±0.17 N/m 2 ; P<0.001) compared with healthy volunteers. BAV with right-handed flow and right- non coronary cusp fusion (n=31) showed more severe flow abnormalities (rotational flow, 38.5±16.5 versus 27.8±12.4 mm 2 /s; P<0.001; systolic flow angle, 29.4°±10.9° versus 19.4°±11.4°; P<0.001; in-plane wall shear stress, 0.64±0.23 versus 0.47±0.22 N/m 2 ; P<0.001) and larger aortas (19.5±3.4 versus 17.5±3.1 mm/m 2 ; P<0.05) than right-left cusp fusion (n=55). Patients with BAV with normal flow patterns had similar aortic dimensions and wall shear stress to healthy volunteers and younger patients with BAV showed abnormal flow patterns but no aortic dilation, both further supporting the importance of flow pattern in the pathogenesis of aortic dilation. Aortic function measures (distensibility, aortic strain, and pulse wave velocity) were similar across all groups. Conclusions—Flow abnormalities may be a major contributor to aortic dilation in BAV. Fusion type affects the severity of flow abnormalities and may allow better risk prediction and selection of patients for earlier surgical intervention. (Circ Cardiovasc Imaging. 2013;6:499-507.)

Ancient bone DNA amplified

Abstract: Reports the successful extraction and amplification of DNA from human bones between 300 and 5500 years of age. Genetic information can be recovered from ancient skeletal material if contamination by modern DNA is avoided. Describes experimental technique and results on a range of bone samples.

Rapid detection of active and latent tuberculosis infection in HIV-positive individuals by enumeration of Mycobacterium tuberculosis-specific T cells.

Abstract: Objectives: An accurate test for Mycobacterium tuberculosis infection is urgently needed. The tuberculin skin test (TST) lacks sensitivity particularly in HIV-infected individuals and has poor specificity because of antigenic cross-reactivity with Bacillus Calmette-Guerin (BCG) vaccination. ESAT-6 and CFP-10 are antigens expressed in M. tuberculosis but not in Mycobacterium bovis BCG and most environmental mycobacteria. We investigated whether T cells specific for these antigens could serve as accurate markers of M. tuberculosis infection in an area of high tuberculosis and HIV prevalence. Methods: Using the rapid ex-vivo enzyme-linked immunospot (ELISPOT) assay for IFN-gamma we enumerated T cells specific for ESAT-6 CFP-10 and purified protein derivative (PPD) in blood samples from 50 Zambian tuberculosis patients 75 healthy Zambian adults and 40 healthy UK residents. TSTs were performed in 49 healthy Zambian adults. Results: All (100%; n=11) and 90% (n=39) of HIV-negative and HIV-positive tuberculosis patients respectively had detectable ESAT-6- or CFP-10-specific T cells. The ESAT-6/CFP-10-based ELISPOT assay was positive in 37 out of 54 HIV-negative healthy Zambians suggesting a 69% prevalence of latent M. tuberculosis infection. Fewer HIV-positive Zambians possessed ESAT-6/CFP-10-specific T cells but the impact of HIV infection was less on this assay than on the PPD-based ELISPOT or TST. Conclusion: The ESAT-6/CFP-10-based ELISPOT assay detects active tuberculosis in HIV-positive individuals with high sensitivity. It is more specific and possibly more sensitive than PPD-based methods of detecting latent M. tuberculosis infection and may potentially improve the targeting of isoniazid preventative therapy to HIV-positive individuals with latent tuberculosis infection. (author’s)