Infección de endoprótesis tras angioplastia ilíaca: ¿es necesaria una profilaxis antibiótica? / Endoprosthesis infection after iliac angioplasty: Is antibiotic prophylaxis necessary?

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Improved design of proton source and low energy beam transport line for European Spallation Source.

The design update of the European Spallation Source (ESS) accelerator is almost complete and the construction of the prototype of the microwave discharge ion source able to provide a proton beam current larger than 70 mA to the 3.6 MeV Radio Frequency Quadrupole (RFQ) started. The source named PS-ESS (Proton Source for ESS) was designed with a flexible magnetic system and an extraction system able to merge conservative solutions with significant advances. The ESS injector has taken advantage of recent theoretical updates and new plasma diagnostics tools developed at INFN-LNS (Laboratori Nazionali del Sud, Istituto Nazionale di Fisica Nucleare). The design strategy considers the PS-ESS and the low energy beam transport line as a whole, where the proton beam behaves like an almost neutralized non-thermalized plasma. Innovative solutions have been used as hereinafter described. Thermo-mechanical optimization has been performed to withstand the chopped beam and the misaligned focused beam over the RFQ input collimator; the results are reported here.

Determination of the mechanical properties of normal and calcified human mitral chordae tendineae.

The aim of the present research is to determine the influence of the calcification of human mitral valves on the mechanical properties of their marginal chordae tendineae. The study was performed on marginal chords obtained from thirteen human mitral valves, explanted at surgery, including six non-calcified, four moderately calcified and three strongly calcified valves. The mechanical response of the chords from the non-calcified and moderately calcified valves was determined by means of quasi-static tensile tests (the poor condition of the strongly calcified valves prevented them from being mechanically characterised). The material parameters that were obtained and analysed (the Young's modulus, the secant modulus, the proportional limit stress, the ultimate strength, the strain at fracture and the density of energy stored up to maximum load) revealed noticeable differences in mechanical behaviour between the two groups of mitral chordae tendineae. Large scatter was obtained in all cases, nevertheless, considering the mean values, it was observed that the normal chords are between three and seven times stiffer or more resistant than the moderately calcified ones. On the contrary, the results obtained for the strain at fracture showed a rather different picture as, in this case, no significant differences were observed between the two families of chords. A scanning electron microscopy study was conducted in order to find out the relevant features of the calcium deposits present in the calcified chordae tendineae. In addition, the general aspects appreciated in the stress vs. strain curves were correlated with the collagen morphological evidences determined microscopically. Finally, the calcium content present in the three groups of chords was quantitatively determined through atomic absorption spectroscopy; then, the relation between the mechanical properties of normal and moderately calcified chords as a function of its calcium content was obtained. This analysis confirmed the existence of a strong correlation between calcium content and stiffness or resistance whereas the influence on the ductility seems to be negligible.

Type IV collagen-initiated signals provide survival and growth cues required for liver metastasis.

The liver is a major site of metastasis for human malignancies, yet the factors that regulate tumor cell survival and growth in this organ remain elusive. Previously, we reported that M-27(IGF-IR) murine lung carcinoma cells with ectopic insulin-like growth factor-1 (IGF-I) receptor overexpression acquired a site-specific, liver-metastasizing potential. Gene expression profiling and subsequent RNA and protein analyses revealed that this was associated with major changes to the expression of extracellular matrix (ECM) protein-encoding genes including type III, IV and XVIII collagen genes, and these changes were also observed in the respective tumors in vivo. Because type IV collagen was the most prominently altered ECM protein in this model, we further analyzed its functional relevance to liver metastasis. M-27 cells stably overexpressing type IV collagen α1 and α2 chains were generated and their growth and metastatic properties investigated. We found that these cells acquired a site-selective growth advantage in the liver and this was associated with cell rescue from anoikis in a collagen IV/α2 integrin/FAK-dependent manner and increased responsiveness to IGF-I. Conversely, collagen IV or focal adhesion kinase (FAK) silencing by small-interfering RNA in highly metastatic tumor cells enhanced anoikis and decreased liver metastases formation. Moreover, analysis of human surgical specimens revealed uniformly high collagen IV expression in 65/65 hepatic metastases analyzed, regardless of tissue of origin, whereas it was variable and generally low in 50/50 primary colorectal carcinoma specimens examined. The results suggest that collagen IV-conveyed signals are essential cues for liver metastasis in diverse tumor types and identify mediators of collagen IV signaling as potential therapeutic targets in the management of hepatic metastases.

Structural and rheological properties of chitosan semi-interpenetrated networks.

The local structure and the viscoelastic properties of semi-interpenetrated biopolymer networks based on cross-linked chitosan and poly(ethylene oxide) (PEO) were investigated by Small Angle Neutron Scattering and rheological measurements. The specific viscosity and the entanglement concentration of chitosan were first determined, respectively, by capillary viscosimetry and steady-state shear rheology experiments performed at different polymer concentrations. Mechanical spectroscopy was then used to study the gelation process of chitosan/PEO semi-interpenetrated networks. By fitting the frequency dependence of the elastic and loss moduli with extended relations of relaxation shear modulus around the sol-gel transition, it was shown that the addition of PEO chains had a significant effect on the viscoelastic properties of aqueous chitosan networks but no effect on the gelation time. The improvement of mechanical properties was in accordance with the correlation length decrease deduced from Small Angle Neutron Scattering experiments.

Surgical treatment of arterial ischemia associated with the use of the angioseal vascular closure device.

BACKGROUND: Despite the theoretical effectiveness of the Angio-Seal closure device to control bleeding after arterial puncture it can increase the risk of ischemia. OBJECTIVES: To describe arterial lesions caused by the device, surgical techniques needed to repair those lesions and surgical outcome in patients who underwent surgery for arterial ischemia after heart catheterization. PATIENTS AND METHODS: Seven patients underwent surgery over a period of 12 months at our institution. Five patients underwent emergency surgery and two a delayed procedure. The cause of ischemia was dissection of an atheroma plaque at the puncture site in four cases, dissection of the superficial femoral artery in one case, thrombosis of the common femoral artery in one case, and plication of the posterior arterial wall in one case. Arterial repair in these patients required the insertion of a vascular graft in three cases, endarterectomy plus angioplasty in two cases, endarterectomy plus graft interposition plus thrombectomy of the superficial femoral artery in one case and endarterectomy plus femoropopliteal bypass in one case. RESULTS: Treatment was successful in all patients. Mean follow up was 7.6 months (range 5-11 months). During the study period one patient died due to cardiopathy. No patients had to be re-operated and no limb losses were recorded. All the patients were asymptomatic from a vascular point of view with normal active lives for their age. CONCLUSIONS: Surgical repair is effective, although, generally, it is not restricted to a simple thrombectomy, requiring the use of different arterial repair techniques.

Endovascular repair of a ruptured giant popliteal artery aneurysm.

An 88-year-old woman with hypertension, chronic vein insufficiency, and repeated cellulites in the right lower extremity was admitted to our hospital with a new episode of right leg inflammation and edema associated with fever and leukocytosis. Due to unilateral enlargement of the leg and D-simer levels of 1000 microg/mL, a concomitant deep venous thrombosis was suspected and ultrasonography was performed. Color duplex-scanning found normal flow in the right deep leg veins but revealed an 11-cm-diameter popliteal artery aneurysm. A computed tomography scan confirmed the diagnosis and revealed a large perianeurysmal hematoma, and angiography provided evidence of perianeurysmal bleeding. The patient was unfit for open surgery, so an endovascular approach under local anesthesia was elected. The aneurysm was successfully excluded with an endograft, and 15 months after surgery, the patient is alive and had an uneventful postoperative course.

Endoluminal repair of a pseudoaneurysm in a patient with cryopreserved arterial allograft of the iliac vessel.

Prosthetic infection is one of the most serious complications of vascular surgery, and its treatment remains a surgical challenge. Good results have been reported using in situ replacement with arterial allografts, but late degeneration of the graft itself may necessitate further repair. We report a case of rupture and pseudoaneurysm formation of an iliac artery homograft urgently treated by endoluminal grafting with complete and immediate exclusion of the sac without complications. At 6-month follow-up angio-computed tomography showed patency of the vascular stent graft without leak evidence. Two years and 6 months after the procedure, the patient is well and alive.

Supervivencia a largo plazo de los injertos grasos / Long-term survival with fat grafting

Presentamos varios casos de pérdida de volumen de diferentes etiologías y en distintas regiones corporales y faciales tratadas mediante injertos de tejido graso autólogo según la técnica de lipoestructura. En ningún caso se realizó sobrecorrección del defecto en ningún caso. La evolución con un seguimiento máximo de 7 años y mínimo de 1 año no mostró disminución del volumen obtenido en el acto quirúrgico en la gran mayoría de los casos. Debido a los resultados obtenidos creemos que el injerto de grasa autólogo es el método de elección para restaurar volúmenes con fines estéticos o reconstructivos (AU)

Volume loss in several facial and body areas was treated by means of autologous fatty tissue grafts with lipostructure technique. There were no cases of overcorrection. The patients’ course, with a maximum follow-up of 7 years and a minimum of 1 year did not evidence any loss of the surgically restored tissue volume in the majority of cases. The above results suggest that autologous fat grafts are the method of choice to restore volume for both cosmetic and reconstructive purposes (AU)

Diclofenac-Na gel is effective in reducing the pain and inflammation associated with exposure to ultraviolet light - results of two clinical studies.

The potential of a diclofenac-Na Emulgel (diclofenac gel) to alleviate the pain and associated symptoms caused by sunburn has been evaluated versus vehicle. Sunburn was induced on the buttock skin of healthy adult male subjects by irradiation with UVA + UVB rays. Investigational products were applied 6 and 10 h after irradiation, and efficacy was assessed on the basis of spontaneous and provoked pain, erythema, oedema, skin colour and temperature. The minimal efficacious concentration evaluated in an extension (0.1 vs. 0.25% diclofenac gel) of a previous concentration-finding study (1, 0.5 and 0.25% diclofenac gel) was 0.1% and was efficacious in alleviating pain (spontaneous and provoked) as well as reducing erythema, oedema and skin temperature. In a single- versus 2-application comparison study, a single application of 0.1% gel was sufficient to alleviate the pain and accompanying symptoms of sunburn with an onset of action 2 h after application. A second application of gel 4 h after the first maintained the analgesia and reduction of other symptoms for a period of up to 48 h after irradiation.

Longitudinal prospective study on quality of life and psychological distress before and one year after liver transplantation.

BACKGROUND: The impact of liver disease and medical complications on quality of life (QOL) and psychological distress before and after liver transplantation (LT) is a matter of growing interest. METHODS: In a longitudinal prospective study, perceived QOL (LEIPAD Quality of Life test) and psychological distress (Brief Symptom Inventory, BSI) were assessed in 25 cirrhotic patients when they were listed for LT and 1, 3, 6 and 12 months after LT. Patients were also evaluated for medical complications and blood levels of immunosuppressive agents. RESULTS: Overall QOL and psychological distress improved significantly and rapidly in most domains from the first month and up to a year after LT. Medical complications and immunosuppressive agents did not correlate with any changes in QOL and psychological distress after LT. When patients were divided according to liver disease etiology: 1. HCV patients listed for LT had worse QOL levels than the group of patients as a whole or the alcoholic liver disease (ALD) patients; 2. HCV patients reported a significant improvement in QOL only 6 and 12 months after LT, and still suffered more psychological distress 12 months after surgery; 3. in ALD patients, overall QOL and psychological distress improved significantly at all follow-up points after LT; 4. HCV patients reported a worse QOL and greater psychological distress 1 and 3 months after LT than the group as a whole or the ALD patients (p < 0.05). CONCLUSIONS: Liver transplantation improves QOL and psychological distress in most recipients, but not in the early stages after LT in patients transplanted for HCV cirrhosis.

Shared and specific susceptibility loci for schizophrenia and bipolar disorder: a dense genome scan in Eastern Quebec families.

The goal of this study was to identify susceptibility loci shared by schizophrenia (SZ) and bipolar disorder (BP), or specific to each. To this end, we performed a dense genome scan in a first sample of 21 multigenerational families of Eastern Quebec affected by SZ, BP or both (N=480 family members). This probably constitutes the first genome scan of SZ and BP that used the same ascertainment, statistical and molecular methods for the concurrent study of the two disorders. We genotyped 607 microsatellite markers of which 350 were spaced by 10 cM and 257 others were follow-up markers in positive regions at the 10 cM scan. Lander and Kruglyak thresholds were conservatively adjusted for multiple testings. We maximized the lod scores (mod score) over eight combinations (2 phenotype severity levels x 2 models of transmission x 2 analyses, affected/unaffected vs affected-only). We observed five genomewide significant linkages with mod score >4.0: three for BP (15q11.1, 16p12.3, 18q12-q21) and two for the shared phenotype, that is, the common locus (CL) phenotype (15q26,18q12-q21). Nine mod scores exceeded the suggestive threshold of 2.6: three for BP (3q21, 10p13, 12q23), three for SZ (6p22, 13q13, 18q21) and three for the CL phenotype (2q12.3, 13q14, 16p13). Mod scores >1.9 might represent confirmatory linkages of formerly reported genomewide significant findings such as our finding in 6p22.3 for SZ. Several regions appeared to be shared by SZ and BP. One linkage signal (15q26) appeared novel, whereas others overlapped formerly reported susceptibility regions. Despite the methodological limitations we raised, our data support the following trends: (i) results from several genome scans of SZ and BP in different populations tend to converge in specific genomic regions and (ii) some of these susceptibility regions may be shared by SZ and BP, whereas others may be specific to each. The present results support the relevance of investigating concurrently SZ and BP within the same study and have implications for the modelling of genetic effects.

Rotational magnetic particles microrheology: the Maxwellian case.

An experimental method based on the rotational dynamics of a magnetic probe is reported to measure the local viscoelasticity of soft materials on microscopic scales. The technique is based on the alignment of dipolar chains of submicrometer magnetic particles in the direction of an applied magnetic field. On one hand, light scattering is used to detect the chains' oscillations over a 0.001-100 Hz frequency range when submitted to an oscillating magnetic field and leads to global microrheological measurements. On the other hand, the chains' rotation toward a permanent magnetic field is observed with a microscope, allowing a local determination of viscoelastic properties on the scale of the chains of particles. We demonstrate the accuracy of both assays with a micellar Maxwellian solution and validate theoretical predictions.

Dynamic viscoelastic properties of silica alkoxide during the sol-gel transition.

The viscoelastic properties of silica alkoxide gel during the sol-gel transition (SGT) are analysed using an extended shear relaxation modulus expression with a functional form based on a product of power law and Debye-Maxwell relaxation kernels. The dynamic properties are probed by small-amplitude oscillatory shear measurements in three viscoelastic domains (pre-SGT, SGT, post-SGT). Using analytical expressions for the storage G'(omega) and loss G''(omega) moduli in these three domains, it is shown that the divergence of the mean characteristic relaxation time in the pre-SGT domain can be successfully described by a percolation with bond fluctuation dynamics. It is also shown that the equilibrium shear modulus in the post-SGT domain can be successfully described by a percolation model based on an analogy with an electrical network. The amplitude and the critical exponent of the power law relaxation at the gelation time first introduced by Winter and Chambon are estimated in the pre- and post-SGT domains.

Flow birefringence, stress optical rule and rheology of four micellar solutions with the same low shear viscosity.

The flow birefringence and the rheological properties of four viscoelastic solutions having nearly the same zero shear viscosity and subjected to shear flows are investigated in the linear and non-linear domains. The surfactant used for the samples is the cetyltrimethylammonium chloride in water at the concentration of 100 mmol/l with an organic salt, the sodium salicylate. The low shear viscosity curve versus the salt concentration is non-monotonic and has two maxima separated by a minimum forming four domains in which the salt concentration is chosen. For the two solutions belonging to the inner branch, i.e. between the two maxima, a simple Maxwellian behaviour is observed and shear banding occurs as confirmed by the flow birefringence pictures. Contrary to the results of P. Fisher (1996) where the unstable flow regime is restricted to the first decreasing part of the low shear viscosity curve of a cetylpyridinium chloride solution, we show that shear banding exits in a wider domain of the salt concentration.

Local rheological probes for complex fluids: application to Laponite suspensions.

We present an experimental method allowing a direct measurement of the local rheological behavior of complex fluids. A magnetic probe is inserted into the bulk of the fluid and submitted to a controlled magnetic force or torque, which induces a mechanical perturbation of the fluid. The geometry of the perturbation can be varied using two kinds of probes: a magnetic bead submitted to a homogeneous magnetic force in one direction, and a magnetic needle that can turn inside the material under the effect of an applied magnetic torque. Two complex viscoelastic fluids are investigated. First, a surfactant solution, which has a linear mechanical behavior in the range of the applied stresses, is used to test and validate the experimental methodology. We then use the local probes to investigate a Laponite colloidal suspension, which exhibits nonlinear behavior such as thixotropy, shear thinning, and aging. In this latter fluid, we find an exponential growth of the rheological relaxation time versus the system age, a power-law dependence of the fluid viscosity on the applied stress, and a dynamical yield stress which saturates with the fluid aging time.

Rheological study of the sol-gel transition in silica alkoxides.

The sol-gel transition of the system tetramethylorthosilicate-water-methanol under basic conditions has been studied by rheological measurements. The gelation time t(g) has been determined from the measurements of the elastic G' and viscous G'' moduli as a function of time at different frequencies according to Winter's criterion. At gelation time the frequency dependence of both moduli follows a power law with an exponent related to the fractal dimension of the network structure. Different initial monomer concentrations, hydrolysis molar ratios, and temperatures are studied. The decrease of the gelation time with an increase of initial monomer concentration or hydrolysis molar ratio is well-described by a power law. An apparent activation energy is deduced from the temperature dependence of gelation time.

Activity and mRNA abundance of Delta-5 and Delta-6 fatty acid desaturases in two human cell lines.

We analyzed fatty acid biosynthesis in Chang and ZR-75-1 cells. Both cell lines could desaturate and further elongate substrates for Delta-5 desaturase. ZR-75-1 but not Chang cells showed Delta-6 desaturation of 18:2n-6, 18:3n-3, 24:4n-6 and 24:5n-3. In both cell lines, the mRNA abundance can be related to Delta-5 or Delta-6 fatty acid desaturase activities. These results suggest that desaturase genes could have, at least in part, independent control mechanisms and that Delta-6 desaturase impairment is not specific to any particular step of the fatty acid metabolic pathways, which may diminish the rationale for the existence of at least two distinct enzymes.

Feasibility and reliability of ankle/arm blood pressure index in preventive medicine.

Despite its potential usefulness for assessing preclinical atherosclerosis and cardiovascular risk, the ankle/arm blood pressure index (AAI) has not yet been the matter of study evaluating its feasibility and reliability by nonspecialist doctors in a general population. This study was planned for two steps. In step 1, the measurement of AAI, (ratio between Doppler systolic pressure at the ankle for each lower limb and the highest value of Doppler systolic pressure of the two upper limbs), should be performed by 50 general practitioners (GPs), 50 social security center physicians, and 50 occupational health physicians in 3,000 male smokers, 40 to 59 years, without clinical cardiovascular disease. In step 2, AAI measurement, coupled with echography-Doppler of iliofemoral arteries, should be repeated by a specialist in all subjects with decreased AAI (<0.90) and the first two subjects with normal AAI recruited in step 1 by each nonspecialist. The number of physicians and subjects participating in step 1 was lower than planned (80 physicians and 962 subjects) with the greatest defect for GPs (six physicians and 35 subjects) and the prevalence of decreased AAI was low (28 subjects). AAI measurement was repeated in step 2 in only 12 subjects with decreased AAI in step 1 and in 124 subjects with normal AAI in step 1. Five of the six subjects with decreased AAI in step 2 also had decreased AAI in step 1 and 123 of the 130 subjects with normal AAI in step 2 also had normal AAI in step 1. As regards echographic stenosis, decreased AAI had a sensitivity of 44% and a specificity of 98%. AAI seems more feasible for occupational health physicians and social security center physicians and AAI is also reliable for nonspecialists previously trained, but its predictive value as regards echographic stenosis is poor in asymptomatic subjects, which may limit its usefulness for detecting preclinical atherosclerosis.