Haemodynamics in axillobifemoral bypass grafts

This thesis is based on four publications on the subject of graft configuration and haemodynamics in axillobifemoral bypass grafts: 1. A clinical evaluation of 17 patients with axillobifemoral bypass graft operations, performed for various indications. Two important observations were made: an asymmetrical blood flow distribution between the two distal branches, in favour of the ipsilateral branch, and turbulent flow at the site of the bifurcation, as observed with duplex scanning. These observations, described in chapter 2, led to the development of a new design for an axillobifemoral bypass graft. 2. The second publication is a report of the results of an in-vitro study, performed to analyse the haemodynamical properties of three currently used axillobifemoral bypass graft configurations (with contralateral branches at angles of 30°,90° and 150° ) and the newly designed axillobifemoral bypass graft. The pressure drops across the four different axillobifemoral bypass bifurcation configurations under sinusoidal flow of a Newtonian fluid were analysed at four different flow rates at three different systemic mean pressures. This invitro experiment is described in chapter 3. 3. The third publication reports on the haemodynamical in-vivo properties of two different axillobifemoral bypass graft configurations (one with a contralateral branch at an angle of 90° and one with a symmetrical bifurcation and flowsplitter). This in-vivo study was conducted, because the in-vitro study was performed with a sinusoidal pulsatile flow of a Newtonian fluid, which has a different impact on flow profi1es and flow disturbances than the in-vivo physiological pulsatile flow of a non-Newtonian fluid, namely blood. All pressure losses across the bifurcation, ipsilateral and contralateral, were measured at different flow rates. The results are discussed in chapter 4. 4. In order to evaluate the clinical relevance of these findings, an international multicenter prospective randomized trial was conducted. The patency rates and clinical behaviour of the two different axillobifemoral bypass grafts, differing only in configuration of the bifurcation (one with a contralateral branch at an angle of 90° and one with a flowsplitter), were analysed in this trial. In 19 centers in Germany, Belgium, France and the Netherlands 117 patients were randomized, 59 receiving a prosthesis with a flowsplitter and 58 a prosthesis with a 90° bifurcation. Analysis of the results after 3 years with a mean follow up of 12 months is discussed in chapter 5

The value of pre-operative ultrasound mapping of the greater saphenous vein prior to 'closed' in situ bypass operations

Objective: The aim of this study was to test pre-operative ultrasound mapping for the detection of duplications and narrow vein segments of the greater saphenous vein (GSV) used as bypass for occlusive arterial disease surgery. Patients and methods: In 44 patients pre-operative ultrasound findings of duplications and lumen assessment of the GSV were compared to the per-operative findings. Results: In nine patients (20%) the pre-operative ultrasound examination showed a duplication. Pre-operative ultrasound had missed a duplication in two cases but had instead shown a narrow segment in both. The pre-operative ultrasound assessment of lumen diameter showed a narrow lumen segment in 10 of the 44 patients. In one patient a per-operatively narrow lumen had not been seen on pre-operative ultrasound. Conclusion: Pre-operative ultrasound mapping of the GSV is a sensitive tool for detection of duplications and narrow vein segments. Since these anatomical variations provide important information for the vascular surgeon, before performing a 'closed' in situ bypass operation, pre-operative vein mapping should be considered when planning such a procedure

A prognostic model for amputation in critical lower limb ischemia

In a (negative) multicenter randomized trial on management for inoperable critical lower limb ischemia, comparing spinal cord stimulation and best medical treatment, a number of pre-defined factors were analyzed for prognostic value. We included a radiological arterial disease score, modified from the SVS/ISCVS runoff score. The purpose of this analysis was to evaluate clinical factors and commonly used circulatory measurements for prognostic modeling in patients with critical lower limb ischemia. We determined the incidence of amputation and its relation to various pre-defined risk factors. A total of 120 patients with critical limb ischemia were included in the study. The integrity of circulation in the affected limb was evaluated on five levels: suprainguinal, infrainguinal, popliteal, infrapopliteal and pedal. A total radiological arterial disease score was calculated from 1 (full integrity of circulation) to 20 (maximally compromised state). We used Cox regression analysis to quantify prognostic effects and differential treatment (predictive) effects. Major amputation occurred in 33% of the patients at 6 months and in 51% at 2 years. The presence of ischemic skin lesions and the radiological arterial disease score were independent prognostic factors for amputation. Patients with ulcerations or gangrene had a higher amputation risk (hazard ratio 2.38, p = 0.018 and 2.30, p = 0.036 respectively) as well as patients with a higher radiological arterial disease score (hazard ratio 1.17 per increment, p = 0.003). We did not observe significant interactions between prognostic factors and the effect of spinal cord stimulation. In conclusion, in patients with critical lower limb ischemia, the presence of ischemic skin lesions and the described radiological arterial disease score can be used to estimate amputation risk

ОБМЕН СООБЩЕНИЯМИ В МИКС-СЕТЯХ

Рассмотрена идея Д.Чаума организации анонимной микс-сети с пересылкой сообщений через каскад миксов (передаточных узлов) и последовательным шифрованием всех промежуточных результатов. Описаны задачи, решаемые миксами в ходе обеспечения анонимности связи, обговариваются проблемы ее безопасности

Chemical composition and quality loss during technological treatment in coho salmon (Oncorhynchus kisutch)

Coho salmon (Oncorhynchus kisutch) supports an important farming production in parallel with capture delivery, giving rise to products of great economic importance in many countries. This review covers the research carried out during the last decades related to its employment as a food product. In a first part, studies carried out concerning the chemical constituent composition and nutritional value are reviewed; a special attention is accorded to the wild/ farmed fish comparison and to the effect of diet on lipid composition variations. In agreement to the great lability of chemical constituents of aquatic foods, the second part of the manuscript provides a revision of coho salmon research related to the chemical component changes produced during technological processing and their effects on nutritional and sensory losses; in this case, a special attention is accorded to studies employing advanced technological strategies focused to partially inhibit the development of the different damage pathways.support provided by the Universidad de Chile (Chile)- Consejo Superior de Investigaciones Científicas (CSIC, Spain) research program through the following projects: Project 2003 CL 0013, Project 2004 CL 0038 and Project 2006 CL 0034. 43Peer reviewe

Galactose inhibition of the constitutive transport of hexoses in Saccharomyces cerevisiae

The relationship between the pathways of glucose and galactose utilization in Saccharomyces cerevisiae has been studied. Galactose (which is transported and phosphorylated by inducible systems) is a strong inhibitor of the utilization of glucose, fructose and mannose (which have the same constitutive transport and phosphorylation systems). Conversely, all these three hexoses inhibit the utilization of galactose, though with poor efficiency. These cross-inhibitions only occur in yeast adapted to galactose or in galactose-constitutive mutants. The efficiency of galactose as inhibitor is even greater than the efficiencies of each of the other three hexoses to inhibit the utilization of each other. Phosphorylation is not involved in the inhibition and transport of sugars is the affected step. The cross-inhibitions between galactose and either glucose, fructose or mannose do not implicate utilization of one hexose at the expense of the other, as it occurs in the mutual interactions between the latter three sugars. it seems that, by growing the yeast in galactose, a protein component is synthesized, or alternatively modified, that once bound to either galactose or any one of the other three hexoses (glucose, fructose or mannose), cross-interacts respectively with the constitutive or the inducible transport systems, impairing their function.This work was supported by a grant (PB87-0206) from the DGICYT, Promoción General del Conocimiento.Peer Reviewe

A prognostic model for amputation in critical lower limb ischemia

In a (negative) multicenter randomized trial on management for inoperable critical lower limb ischemia, comparing spinal cord stimulation and best medical treatment, a number of pre-defined factors were analyzed for prognostic value. We included a radiological arterial disease score, modified from the SVS/ISCVS runoff score. The purpose of this analysis was to evaluate clinical factors and commonly used circulatory measurements for prognostic modeling in patients with critical lower limb ischemia. We determined the incidence of amputation and its relation to various pre-defined risk factors. A total of 120 patients with critical limb ischemia were included in the study. The integrity of circulation in the affected limb was evaluated on five levels: suprainguinal,infrainguinal, popliteal, infrapopliteal and pedal. A total radiological arterial disease score was calculated from 1 ( full integrity of circulation) to 20 (maximally compromised state). We used Cox regression analysis to quantify prognostic effects and differential treatment (predictive) effects. Major amputation occurred in 33% of the patients at 6 months and in 51% at 2 years. The presence of ischemic skin lesions and the radiological arterial disease score were independent prognostic factors for amputation. Patients with ulcerations or gangrene had a higher amputation risk (hazard ratio 2.38, p = 0.018 and 2.30, p = 0.036 respectively) as well as patients with a higher radiological arterial disease score (hazard ratio 1.17 per increment, p = 0.003). We did not observe significant interactions between prognostic factors and the effect of spinal cord stimulation. In conclusion, in patients with critical lower limb ischemia, the presence of ischemic skin lesions and the described radiological arterial disease score can be used to estimate amputation risk

Feasibility study of a home-based sensory training system (STS) device for type 1 complex regional pain syndrome in England: Lessons learnt

IntroductionSensory discrimination training has demonstrated improvements in two-point discrimination and pain reduction in people with chronic pain. We tested the feasibility and acceptability of a novel Sensory Training System (STS) device in the homes of people with Type 1 Complex Regional Pain Syndrome (CRPS).MethodsParticipants meeting CRPS diagnostic criteria were invited to use the STS for a minimum of 30 minutes per day for 30 days. Device usage data were captured by the STS. Assessments at baseline and after 30 days were: two-point discrimination ability, pain intensity and interference, sensitivity and emotions towards CRPS limb. Qualitative interviews were conducted at the end of the study to capture participants’ feedback on the device.ResultsA total of 10 participants (female n = 7) completed the study. Participants’ mean age was 56.4 years (range: 24–78 years), and mean disease duration was 9.37 years (range: 4.25–26.5). Eight had lower limb CRPS. The mean STS device use was 27.3 ± 3.4 days and mean daily usage of training games was 00:27:11 ± 00:07:52 (hh:mm:ss). No patterns or trends were evident between device usage and outcome data.ConclusionThis feasibility study of a home-based STS for people with CRPS revealed key areas for improvement in the device’s hardware and software and outlined the challenges of development and testing during the COVID-19 pandemic, while also capturing valuable usability insights from participant feedback. Key recommendations include early and ongoing collaboration with users, securing sufficient funding, ensuring correct device setup by participants, conducting interim analysis, and using online tools to enhance participant experience and data collection

Brain age as a biomarker for pathological versus healthy ageing – a REMEMBER study

Objectives: This study aimed to evaluate the potential clinical value of a new brain age prediction model as a single interpretable variable representing the condition of our brain. Among many clinical use cases, brain age could be a novel outcome measure to assess the preventive effect of life-style interventions. Methods: The REMEMBER study population (N = 742) consisted of cognitively healthy (HC,N = 91), subjective cognitive decline (SCD,N = 65), mild cognitive impairment (MCI,N = 319) and AD dementia (ADD,N = 267) subjects. Automated brain volumetry of global, cortical, and subcortical brain structures computed by the CE-labeled and FDA-cleared software icobrain dm (dementia) was retrospectively extracted from T1-weighted MRI sequences that were acquired during clinical routine at participating memory clinics from the Belgian Dementia Council. The volumetric features, along with sex, were combined into a weighted sum using a linear model, and were used to predict ‘brain age’ and ‘brain predicted age difference’ (BPAD = brain age–chronological age) for every subject. Results: MCI and ADD patients showed an increased brain age compared to their chronological age. Overall, brain age outperformed BPAD and chronological age in terms of classification accuracy across the AD spectrum. There was a weak-to-moderate correlation between total MMSE score and both brain age (r = -0.38,p < .001) and BPAD (r = -0.26,p < .001). Noticeable trends, but no significant correlations, were found between BPAD and incidence of conversion from MCI to ADD, nor between BPAD and conversion time from MCI to ADD. BPAD was increased in heavy alcohol drinkers compared to non-/sporadic (p = .014) and moderate (p = .040) drinkers. Conclusions: Brain age and associated BPAD have the potential to serve as indicators for, and to evaluate the impact of lifestyle modifications or interventions on, brain health