Growth of two peat-forming mosses in subarctic mires: species interactions and effects of simulated climate change

In patches of co-occurring species in natural plant communities, there is a finely poised balance between species in the ways in which they respond to prevailing moisture and temperature regimes. However, environmental change scenarios, in which temperature, moisture and ultraviolet-B radiation are suggested to increase, may favour one of the species. The imbalance is likely to occur at the levels of interactions between patches of the different species and at the shoot level when neighbouring shoots belong to different species. We increased temperature and UV-B in a two-way factorial experiment and increased water supply independently in two subarctic mire communities dominated by the mosses Sphagnum fuscum and Dicranum elongatum. The effects of simulated increase in UV-B were studied using two separate radiation systems, i.e. a square wave system and a modulated system. When precipitation was enhanced, both species showed an increase in growth but this was not sustained beyond 5 mm per day. S. fuscum showed a 50 greater response to enhanced precipitation than did D. elongatum, as would be expected from their habitat preferences. Under ambient temperature, S. fuscum grew 67 faster than D. elongatum and this relative difference in response was maintained after one year under a temperature enhancement. The response by species over the winter period was moderated by their neighbours. S. fuscum growth was enhanced when it grew next to D. elongatum whereas D. elongatum grew better with neighbours of its own species. Increased temperature and UV-B radiation did not affect the interaction between the species. Although a balance was maintained between the two species over the short duration of the experiment, potential was shown for an imbalance to occur over longer periods and particularly if winter warming and precipitation are greater than those in summer. During the peak growing season 20 increased UV-B over ambient had a negative effect on S. fuscum under increased temperature but there were no overall seasonal effects on either species, irrespective of method of UV supplementation

UVB-induced inflammation gives increased d-dopachrome tautomerase activity in blister fluid which correlates with macrophage migration inhibitory factor.

UVB light was used to induce an experimental inflammation in normal human skin in order to investigate its correlation with the activity of the newly described enzyme d-dopachrome tautomerase (DDT) in the fluid of experimental blisters. Macrophage migration inhibitory factor (MIF) activity was determined as a closely related marker of inflammation. DDT and MIF activities were demonstrated in blister fluids in all 10 healthy subjects. All but one of these subjects showed increased activity of DDT and MIF after three minimal erythemal doses (MED) of UVB. The mean activity of DDT increased approximately twofold and the mean activity of MIF also increased twofold after UVB in our experimental model. We found a strong correlation between DDT and MIF activities. The presence of DDT in epidermis and its increase at UV irradiation was confirmed by immunohistochemical studies. In this study, DDT is for the first time demonstrated in the skin. It is also the first time DDT can be related to inflammation, and its covariation with MIF strengthens this observation

In situ bending of thoracic stent grafts: Clinical application of a novel technique to improve conformance to the aortic arch

PurposeA straight thoracic stent graft often complies poorly with the curvature of the aortic arch. We have previously reported an in vitro model of a modified stent graft that can be bent in situ after deployment to improve conformance to the aortic arch. We now report the first clinical experience with this technique in three consecutive patients.MethodsBetween September 2007 and August 2008, three patients were treated for different pathologies of the aortic arch with a modified thoracic stent graft that was fitted with a sliding self-locking knot and a detachable Bowden cable. Transfemoral traction on the Bowden cable enables controlled shortening of the proximal part of the stent graft at the inner curve after deployment. The stent graft is thereby directed to allow for better apposition to the aortic wall.ResultsThe modified thoracic stent grafts were correctly orientated and deployed in all patients. Transfemoral traction on the Bowden cable successfully bent all stent grafts and improved vessel wall apposition without a residual gap on the inner curve. The Bowden cable was successfully released and withdrawn in all patients.ConclusionIn situ bending of thoracic stent grafts with a sliding self-locking knot is feasible and improves proximal apposition of the device at the inner curve of the aortic arch. More data and longer follow-up are required to confirm the applicability of this technique

Chimney grafts preserve visceral flow and allow safe stenting of juxtarenal aortic occlusion

ObjectiveChimney grafts have proven useful for urgent endovascular repair of juxtarenal aortic aneurysms. Stenting of juxtarenal aortic occlusive disease is not routinely advocated due to the risk of visceral artery obstruction. We report on the potential applicability of chimney grafts in 10 patients with juxtarenal aortic stenosis or occlusion. To our best knowledge, chimney grafts have not been applied previously in this challenging setting.MethodsTen high-risk female patients (mean age, 68 years) with severe stenosis or occlusion of the aorta at the level of the visceral arteries were offered stenting. “Chimney” stents or stent grafts (20-40 mm long) were implanted from a brachial approach into visceral arteries that needed to be covered by the aortic stent. The chimney stents were then temporarily obstructed by balloon catheters to prevent visceral embolization until the aortic stent or stent graft was deployed.ResultsAll procedures were technically successful, and patency was obtained in all visceral arteries and the aorta without distal embolization. One patient died after 9 days of acute heart failure. The nine surviving patients presented no complications, and all stented vessels remained patent at up to 6 years. Another patient died after 5.5 years due to lung cancer. All three patients with renal impairment have improved renal function, and a reduction in antihypertensive medication has been possible.ConclusionsChimney grafts may allow stenting of juxtarenal aortic occlusive disease by protecting the patency of visceral arteries. Further evaluation with more patients and longer follow-up is required

Intra-aneurysm sac pressure measurements after endovascular aneurysm repair: differences between shrinking, unchanged, and expanding aneurysms with and without endoleaks

AbstractObjectiveOur objective was to study intra-aneurysm pressure after endovascular aneurysm repair (EVAR) in shrinking, unchanged, and expanding abdominal aortic aneurysms (AAAs) with and without endoleaks.MethodsDirect intra-aneurysm sac pressure measurement (DISP) by percutaneous translumbar puncture of the AAA under fluoroscopic guidance was performed 46 times during the follow-up of 37 patients (30 men; median age, 73 years [range, 58-82 years]; AAA diameter: median, 60 mm [range, 48-84 mm]). Three patients were included in two different groups because DISP was performed more than once with different indications. Tip-pressure sensors mounted on 0.014-inch guidewires were used for simultaneous measurement of systemic and AAA sac pressures. Mean pressure index (MPI) was calculated as the percentage of mean intra-aneurysm pressure relative to the simultaneous mean intra-aortic pressure.ResultsMedian MPI was 19% in shrinking (11 patients), 30% in unchanged (10 patients), and 59% in expanding (9 patients) aneurysms without endoleaks. Pulse pressure was also higher in expanding (10 mm Hg) compared with shrinking (2 mm Hg; P < .0001) AAAs. Four of the nine patients with expanding AAAs underwent five repeated DISPs later in the follow-up, and MPIs were consistently elevated. Seven of the 10 patients with unchanged AAAs without endoleaks underwent further computed tomography follow-up after DISP; 2 expanded (MPI, 47%-63%), 4 shrank (MPI, 21%-30%), and 1 remained unchanged (MPI, 14%). Type II endoleaks (6 patients, 7 DISPs) were associated with wide range of MPI (22%-92%). Successful endoleak embolization (n = 4) resulted in pressure reduction.ConclusionsIntra-aneurysm sac pressure measurement is an important adjunctive for EVAR evaluation, possibly allowing early detection of failures. High pressure is associated with AAA expansion and low pressure with shrinkage. Type II endoleaks can be responsible for AAA pressurization, and successful embolization appears to result in pressure reduction

Spatial impairment following right hemisphere transient ischaemic attacks in patients without carotid artery stenosis

Neuropsychological testing was performed on: 10 right-handed patients who had had 1-4 right hemisphere transient ischaemic attacks (TIAs), 10 normal controls, 10 house painters with long-term exposure to organic solvents, and 10 patients with liver cirrhosis. The subjects in each group were matched for age and education. No TIA patient had significant internal carotid artery stenosis, and CT was normal except in one patient, although magnetic resonance imaging (MRI) performed 3 years after the testing was abnormal in 4/8 cases. No patient reported additional distinct TIAs during the period between neuropsychological testing and MRI. The TIA patients showed lateralized signs of spatial impairment, whereas the cirrhotics and also (but to a lesser degree) the house painters showed signs of diffuse cerebral dysfunction. The study shows that hemispheric TIAs in patients without significant internal carotid artery stenosis may result in persistent focal cognitive impairment. This can be demonstrated with sensitive neuropsychological instruments even when MRI is normal

Revascularization options for left subclavian salvage during TEVAR.

This article reviews the solutions for the revascularization of the left subclavian artery during thoracic endovascular aortic repair (TEVAR). Open surgical revascularization has been the predominant technique used but recent developments may lead to an increasing role of the endovascular revascularization. The different open and endovascular technical options are discussed and the results summarized