Imperial College London

Dr Jonathan Underwood

Faculty of MedicineDepartment of Infectious Disease

Honorary Clinical Research Fellow
 
 
 
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Contact

 

+44 (0)20 3312 1466jonathan.underwood Website CV

 
 
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Location

 

Winston Churchill WingSt Mary's Campus

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Summary

 

Publications

Publication Type
Year
to

40 results found

Underwood J, Cole JH, Sharp D, Winston A, Leech R, Majoie C, Caan M, De Francesco D, van Zoest R, Geurtsen G, Schmand B, Wit F, Reiss P, Sabin Cet al., 2016, Brain MRI changes associated with poorer cognitive function despite suppressive antiretroviral therapy, 22nd Annual Conference of the British HIV Association (BHIVA), Publisher: Wiley, Pages: 6-6, ISSN: 1464-2662

Conference paper

Scott J, Underwood J, Garvey LJ, Mora-Peris B, Winston Aet al., 2016, A comparison of two post-processing analysis methods to quantify cerebral metabolites measured via proton magnetic resonance spectroscopy in HIV disease., British Journal of Radiology, Vol: 89, ISSN: 1748-880X

OBJECTIVE: Non-invasive biomarkers to monitor cerebral function in treated human immunodeficiency virus (HIV) disease are required. Cerebral metabolite ratios (CMRs) measured by proton-MR spectroscopy ((1)H-MRS) are a potential biomarker. Here, we compare two post-processing software packages to quantify CMRs. METHODS: Cerebral (1)H-MRS data from 11 HIV-positive subjects before and after antiretroviral therapy intensification with maraviroc were quantified using a java-based version of the MR user interface package (jMRUI) and the totally automatic robust quantitation in nuclear MR (TARQUIN). (1)H-MRS data included N-acetylaspartate (NAA), creatine (Cr), choline (Cho) and myo-inositol (mI) from three cerebral locations. Differences in quantification and clinical associations of CMRs measured by the two packages were evaluated. RESULTS: Mean CMRs were generally lower when measured by TARQUIN than by jMRUI (NAA/Cr, Cho/Cr, mI/Cr ratios of 1.78, 0.83, 0.81 for jMRUI, and 1.27, 0.25, 0.81 for TARQUIN). Longitudinal changes were observed in CMRs in the basal ganglia voxel although these changes were not statistically significant [+7.1% (p = 0.18), +0.0% (p = 0.91) and -6.6% (p = 0.61) and +14.8% (p = 0.18), +17.9% (p = 0.07) and +34.8% (p = 0.17) for NAA/Cr, Cho/Cr and mI/Cr ratios measured by TARQUIN and jMRUI, respectively]. Plasma maraviroc concentration was associated with a decrease in mI/Cr ratio measured via TARQUIN (p = 0.049). CONCLUSION: Although CMRs differed when quantified by jMRUI vs TARQUIN, these differences were consistently observed across three cerebral locations, and clinical associations were evident by both methods. ADVANCES IN KNOWLEDGE: TARQUIN and jMRUI are viable options to use in the post-processing of cerebral MRS data acquired in HIV disease.

Journal article

Winston A, Underwood J, 2016, Plasma Biomarkers of HIV-associated Cognitive Disease., EBioMedicine, Vol: 3, Pages: 12-13

Journal article

Underwood J, 2015, Cognitive deficits persist in the combination antiretroviral era: Preliminary results from the Co-morBidity in Relation to AIDS (COBRA) collaboration London cohort, 12th International Symposium on the Neurobiology and Neuroendocrinology of Aging, Publisher: Elsevier, Pages: 104-104, ISSN: 1873-6815

Background: HIV is a neurotropic virus that if left untreated leads to a frank dementia in a significant proportion of patients. Modern combination antiretroviral therapy (cART) has transformed HIV into a chronic disease with life expectancy approaching normal. The more severe forms of HIV associated neurocognitive dysfunction (HAND) are now rarely seen but there have been many reports of more subtle cognitive deficits occurring in up to 50% of patients in the modern era. Unfortunately many previous studies have had heterogeneous patient groups or lacked appropriate controls making extrapolation to well treated patients, common in current practice, difficult. This study set out to investigate the true prevalence of cognitive dysfunction and the mechanisms underlying it in an older group of HIV positive individuals on effect cART.Methods: To date 46 participants (33 HIV-positive patients and 13 HIV-negative controls) have been recruited into the London cohort of the COBRA observational study. All participants were aged over 50 (mean age 61 ± 7.7 years) and were predominantly male (87%). All HIV positive patients were on fully suppressive stable cART > 12 months. The two groups were well matched in terms of age, gender, sexual orientation, ethnicity and educational attainment. Subjects underwent a full cognitive battery in addition to MRI scanning with a 64-direction diffusion protocol. Mean FA (fractional anisotropy) for the major white matter tracts was calculated using a white matter skeleton created from the centre of tracts common to the group and standard atlases.Results: Poorer performance on trail making tests A and B (p = 0.007 and < 0.001 respectively), the Stroop test (p = 0.006), grooved peg board test (p = 0.004) and the Wisconsin card sort test (p = 0.002) were observed in the HIV-positive group compared to the control group. After adjusting for age the mean white matter skeleton FA was highly significantly correlated (p < 0.01) with all

Conference paper

Winston A, Underwood J, 2015, Emerging concepts on the use of antiretroviral therapy in older adults living with HIV infection, CURRENT OPINION IN INFECTIOUS DISEASES, Vol: 28, Pages: 17-22, ISSN: 0951-7375

Journal article

Underwood J, Robertson KR, Winston A, 2015, Could antiretroviral neurotoxicity play a role in the pathogenesis of cognitive impairment in treated HIV disease?, AIDS, Vol: 29, Pages: 253-261, ISSN: 0269-9370

Journal article

Underwood J, 2014, Bone, joint and soft tissue infections, Oxford Handbook of Tropical Medicine, Editors: Brent, Davidson, Seale, Publisher: Oxford University Press, ISBN: 9780199692569

The new edition of this unique handbook continues to provide an accessible and comprehensive, signs-and-symptoms based source of information on medical problems commonly seen in the tropics.

Book chapter

Underwood J, 2013, RECURRENT UTI IN NON-PREGNANT WOMEN Don't forget the embalming fluid for treating recurrent infections ..., BMJ-BRITISH MEDICAL JOURNAL, Vol: 346, ISSN: 1756-1833

Journal article

Underwood J, Klein JL, Newsholme W, 2011, Escherichia coli bacteraemia: how preventable is it?, Journal of Hospital Infection, Vol: 79, Pages: 364-365, ISSN: 0195-6701

Summary Mandatory bacteraemia reporting was extended to include Escherichia coli from June 2011. The purpose of this study was to investigate whether the success seen in reducing meticillin-resistant Staphylococcus aureus infection rates could be duplicated with E. coli. All cases of E. coli bacteraemia occurring at our Trust in 2010 were reviewed. There were 216 episodes of E. coli bacteraemia, of which 63% were community-acquired. Only 19% had a potentially preventable cause identified, the majority (71%) of whom had urinary catheter-associated bacteraemia. These data must be kept in mind should targets to reduce E. coli bacteraemia be set in the future.

Journal article

Cowie MR, Komajda M, Murray-Thomas T, Underwood J, Ticho Bet al., 2006, Prevalence and impact of worsening renal function in patients hospitalized with decompensated heart failure: results of the prospective outcomes study in heart failure (POSH), EUROPEAN HEART JOURNAL, Vol: 27, Pages: 1216-1222, ISSN: 0195-668X

Journal article

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