Is having sex with other men a risk factor for transfusion-transmissible infections in male blood donors in Western countries?: a systematic review

Background : Although increased prevalence of transfusion transmissible infections (TTI) among “men who have sex with men” (MSM) has been well documented, the exclusion of MSM as blood donors is contested. The aim of this systematic review is to find studies that describe the risk of TTI in MSM blood donors. Methods : We searched MEDLINE, Embase, The Cochrane Central Register of Controlled Trials, Cinahl, and Web of Science, and used GRADE for determining evidence quality. We included studies comparing MSM and non-MSM blood donors (or people eligible to give blood), living in areas most relevant for our Blood Service. Results : Out of 18 987 articles, 14 observational studies were included. Two studies directly compared MSM with non-MSM donors showing that MSM donors have a statistically significant higher risk of HIV-1 infections. In one of these studies it was shown that this was related to recent (< 12 months) MSM contact. In two additional studies no evidence was shown in favour of a certain deferral period for MSM. Ten studies, applying permanent deferral for MSM, compared infected versus non-infected donors. One study found that MSM is a statistically significant risk factor for HIV-1 infection in blood donors. For other TTI such as HBV or HCV, an increased risk of infection could not be demonstrated, because the precision of the results was affected by the low numbers of donors with MSM as risk factor, or because of risk of bias in the included studies. All studies included low level evidence, because of risk of bias and imprecision of the results. Conclusions : High-quality studies investigating the risk of TTI in MSM who donate blood are scarce. The available evidence suggests a link between MSM blood donors and HIV-1 infection, but is too limited to be able to unambiguously/clearly recommend a certain deferral policy

Imaging cerebrovascular health using 7T MRI

Magnetic resonance imaging is a valuable clinical tool for the visualization of intracranial vasculature. Without exposing patients to ionizing radiation or intravenous contrasts, it can provide multi-modal structural information about the shape, structure, and function of the various vessels involved in stroke and dementia. However, imaging methods are limited by the achieved contrasts and resolutions, as well as the required scan times. Ultra-high field 7T MRI offers increased signal-to-noise ratio and desirable changes in relaxation parameters, therefore promising substantial improvements to existing neurovascular MRI approaches such as MR angiography (MRA) and MR vessel wall imaging (VWI). However, 7T MRI also introduces increased specific absorption rates and reduced homogeneity and extent of the transmit B1 field. Because of the latter, the first research chapter in this thesis (Chapter 3) studies the possibility to increase the extent of this 7T B1+ field into the feeding arteries in the neck using parallel transmission (pTx). The second research chapter (Chapter 4) aims to improve the accelerated acquisition of high-resolution MRA using compressed sensing reconstruction. This facilitates the visualization of the small intracranial arteries which are involved in lacunar infarcts and vascular dementia, which can be achieved within clinical scan times. The final parts of this thesis (Chapters 5-7) focus on a specific intracranial VWI sequence called DANTE-SPACE. A simulation framework for the sequence is first presented in Chapter 5. This framework includes various additional processes such as (pulsatile) tissue motion and B1+ variations to accurately represent the intra- and extra-vascular contrast mechanisms. The simulations are then used for the optimization and comparison of the T2-weighted DANTE-SPACE sequence at 3T, 7T without pTx, and 7T with pTx. The optimizations aim to maximize the contrast between both the blood within and the cerebrospinal fluid surrounding intracranial vessel walls, and the comparison between different field strengths provides a first quantitative indication of the added value of ultra- high field MRI for the DANTE-SPACE sequence

Seed produced anti ETEC antibodies for oral passive immunisation of piglets against post weaning diarrhoea

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