Local temperature-sensitive mechanisms are important mediators of limb tissue hyperemia in the heat-stressed human at rest and during small muscle mass exercise.

Limb tissue and systemic blood flow increases with heat stress, but the underlying mechanisms remain poorly understood. Here, we tested the hypothesis that heat stress-induced increases in limb tissue perfusion are primarily mediated by local temperature-sensitive mechanisms. Leg and systemic temperatures and hemodynamics were measured at rest and during incremental single-legged knee extensor exercise in 15 males exposed to 1 h of either systemic passive heat-stress with simultaneous cooling of a single leg (n=8) or isolated leg heating or cooling (n=7). Systemic heat-stress increased core, skin and heated leg blood (Tb) temperatures, cardiac output and heated leg blood flow (LBF, 0.6 ± 0.1 l.min(-1); P0.05). Increased heated leg deep tissue BF was closely related to Tb (R(2) = 0.50; P0.05), despite unchanged systemic temperatures and hemodynamics. During incremental exercise, heated LBF was consistently maintained ~ 0.6 l.min(-1) higher than that in the cooled leg (P<0.01), with LBF and vascular conductance in both legs showing a strong correlation with their respective local Tb (R(2) = 0.85 and 0.95, P<0.05). We conclude that local temperature-sensitive mechanisms are important mediators in limb tissue perfusion regulation both at rest and during small-muscle mass exercise in hyperthermic humans.The invasive study was partially funded by Gatorade Sports Science Institute, PepsiCo

Contained rupture of an aortic arch aneurysm in a patient with syphilitic aortitis. A case report

Syphilitic aortitis is a rare complication of tertiary syphilis, which can lead to aortic aneurysm formation, aortic valvular insufficiency, and ostial coronary stenosis. Syphilis has re-emerged worldwide over recent decades and vascular surgeons should be aware of its cardiovascular manifestations. Atypical clinical presentation, such as hemoptysis and a computed tomography angiography pattern of a thicker aneurysmal wall with ulcer-like aneurysm projections, should raise suspicion of syphilitic aortic aneurysm. An early diagnosis and appropriate surgical and medical therapies significantly contribute to successful treatment and favorable prognosis. Herein is reported the case of an 82-year-old male patient, positive for syphilis infection, with impending aortic arch aneurysm rupture treated with a hybrid arch repair. After 7 months, the patient was brought to the emergency room in cardiac arrest. Unsuccessful cardiopulmonary resuscitation maneuvers were performed, and an autopsy showed cardiac tamponade due to rupture of the ascending aorta

The relevance of hydroxyapatite and spongious titanium coatings in fixation of cementless stems. An experimental comparative study in rat femur employing histological and microangiographic techniques.

Pure titanium rods plasma-spray coated with hydroxyapatite (HA) or porous titanium (Ti) of controlled roughness were implanted bilaterally in the distal femur of Sprague-Dawley rats to compare the extent of bone growth on the two types of coating. The relevance of other factors, like mechanical stability and biological adaptation of the bone to the insertion of a foreign body implant, were investigated in femora which were over-reamed (absence of primary fit) or reamed without insertion of the rod. Continuous tetracycline labeling for the first 30 days and for the last 2 weeks in the 90-day group was performed; histological/histometric, fluorescence and microangiographic studies were carried out on serial sections of the implanted and control femora. In the group of stable implants, HA-coated rods showed 90% integration versus 53% with Ti-coated implants (P < 0.001); in over-reamed implants neither surface bone growth nor endosteal fixation occurred, and both types of rods were surrounded by a thick layer of connective tissue. The study documented early adhesion of osteoblasts and direct deposition of bone matrix on the substrate, while on spongious titanium osteogenesis was observed only in proximity to the surface. Remodeling of the reactive, primary bone to mature, lamellar bone took the form of a capsule surrounding the implants and radial bridges connecting the latter to the endosteal surface. The number, height and thickness of these bridges appeared to be the factors determining implant stability, rather than the extent of the bony capsule on the perimeter of the implant. Integration was a function not only of mechanical conditions and surface geometry, but also of the biological response of the whole bone to changes in the vascularization pattern. The reported phenomena can be seen more easily in experimental models involving small rodents because of their fast bone turnover and revascularization, but it is expected that they take place, even at a lower speed, in clinical situations like cementless stems of total hip replacement

Endovascular Treatment of Aortic Arch Aneurysms

AbstractIntroductionThe aim of this study was to review our clinical experience with endovascular treatment of aortic arch aneurysms using different commercially available grafts (Gore, Talent, Endomed, Cook).MethodsFrom 1999 to 2004, 97 patients received endovascular treatment for diseases of the thoracic aorta. In 30 cases (26 males, 4 females) the aortic arch was involved.The left subclavian artery was overstented (Ishimaru zone ‘2’) in 18 cases (60%). Only in the first three cases had the subclavian artery been revascularized. The left common and subclavian arteries were covered (zone ‘1’) in 6 (20%) cases—all had the carotid artery reconstructed, either simultaneously (five cases) or as a staged procedure (one case). Finally, the whole aortic arch was over-stented (zone ‘0’) in 6 (20%) cases, with simultaneous (five cases) or staged (one case) grafting of the supra-aortic vessels from the ascending aorta.ResultsPerioperative mortality was 2/30 (7%), due to graft migration (zone ‘2’) and intra-operative stroke (zone ‘0’), respectively. One minor stroke was observed. No cases of paraplegia were recorded. Three type I endoleaks were observed. Two resolved at 6 months follow-up; one zone ‘0’ graft is still being followed. There was one surgical conversion for endograft failure 2 weeks after implantation. Thus, the technical success rate was 87% (26/30) cases. The mean follow-up time was 23±17 months. No new onset endoleaks or aneurysm-related deaths were recorded.ConclusionsCurrently available grafts may be deployed in the aortic arch in most instances. De-branching of the aortic arch with surgical revascularization for zone ‘0’ and ‘1’ seems to be adequate to obtain a satisfactory proximal landing zone

O-17 Hyperfine Spectroscopy Reveals Hydration Structure of Nitroxide Radicals in Aqueous Solutions

The hydrationstructureof nitroxideradicalsin aqueoussolutionsis elucidatedby advanced17Ohyperfine(hf) spectroscopywith supportof quantumchemicalcalculationsand MD simulations.A piperidineand a pyrrolidine-basednitroxideradical are comparedand show clear differencesin the preferreddirectionalityof H-bondformation.We demonstratethat thesescenariosare best representedin17O hf spectra,wherein-planecoordinationovers-type H-bondingleads tolittle spin densitytransferon the water oxygenand smallhf couplings,whereasp-type perpendicularcoordinationgeneratesmuch larger hf couplings.Quantitativeanaly-sis of the spectrabased on MD simulationsand DFTpredictedhf parametersis consistentwith a distributionof close solvatingwater molecules,in which direction-ality is influencedby subtle steric effects of the ring andthe methyl group substituents

Quantum error correction with molecular spin qudits

Thanks to the large number of levels which can be coherently manipulated, molecular spin systems constitute a very promising platform for quantum computing. Indeed, they can embed quantum error correction within single molecular objects, thus greatly simplifying its actual realization in the short term. We consider a recent proposal, which exploits a spin qudit to encode the protected unit, and is tailored to fight pure dephasing. Here we compare the implementation of this code on different molecules, in which the qudit is provided by either an electronic or a nuclear spin (S, I &gt; 1), coupled to a spin-1/2 electronic ancilla for error detection. By thorough numerical simulations we show that a significant gain in the effective phase memory time can be achieved. This is further enhanced by exploiting pulse-shaping techniques to reduce the leakage and/or the impact of decoherence during correction. Moreover, we simulate the implementation of single-qubit operations on the encoded states