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Biomedical subjects

J Sanz

Publications and source records attributed to J Sanz.

At least 19 recordsLinked to original sources
PubMed2006

Development of a robust method for the quantitative determination of disaccharides in honey by gas chromatography.

An iterative method for the GC quantitative determination of TMS-oxime disaccharides in honey has been developed. This approach takes into account possible positive systematic errors caused by unidentified compounds which overlap with the expected disaccharides. The results of its application to the determination of 15 disaccharides in simulated honey samples indicate that the iterative method is more robust that methods based on least-squares regression, improves the accuracy of the quantitative analysis and allows to detect the possible presence of disaccharides not identified.

Chromatography, Gas↗
PubMed2006

LACE-conditioned autologous stem cell transplantation for relapsed or refractory Hodgkin's lymphoma: treatment outcome and risk factor analysis in 67 patients from a single centre.

High-dose chemotherapy followed by autologous stem cell transplantation (ASCT) is a recognized treatment option for patients with relapsed Hodgkin's lymphoma. We have analysed 67 patients who underwent ASCT after LACE (lomustine (CCNU), cytarabine (Ara-C), cyclophosphamide, etoposide) conditioning for relapsed (n=61) or primary refractory (n=6) Hodgkin's lymphoma. The 100-day treatment-related mortality was 3%. With a median follow-up of 67 months (range 3.3-161.0) the probabilities of overall survival (OS) and progression-free survival (PFS) at 5 years were 68 and 64%, respectively. Probabilities for OS and PFS at 5 years for patients with chemosensitive relapse (n=40) were 81 and 78% versus 50 and 35%, respectively, for patients (n=27) with chemoresistant relapse (P=0.012 for OS, P=0.002 for PFS). In multivariate analysis mixed cellularity classical or lymphocyte-depleted classical histology subtype and haemoglobin level of 10 g/dl or less at the time of ASCT were identified as risk factors for worse OS, whereas stage III or IV disease at diagnosis and disease status at ASCT other than complete or partial remission predicted inferior PFS. LACE followed by ASCT is an effective treatment for the majority of patients with chemosensitive relapsed Hodgkin's lymphoma and a proportion of chemorefractory patients also benefit.

Adolescent↗
PubMed2006

Bubble acceleration in the ablative Rayleigh-Taylor instability.

The highly nonlinear evolution of the single-mode Rayleigh-Taylor instability (RTI) at the ablation front of an accelerated target is investigated in the parameter range typical of inertial confinement fusion implosions. A new phase of the nonlinear bubble evolution is discovered. After the linear growth phase and a short constant-velocity phase, it is found that the bubble is accelerated to velocities well above the classical value. This acceleration is driven by the vorticity accumulation inside the bubble resulting from the mass ablation and vorticity convection off the ablation front. While the ablative growth rates are slower than their classical values in the linear regime, the ablative RTI grows faster than the classical RTI in the nonlinear regime for deuterium and tritium ablators.

Journal Article↗
PubMed2006

Stomatal conductance of semi-natural Mediterranean grasslands: implications for the development of ozone critical levels.

Intra-genus and intra-specific variation and the influence of nitrogen enrichment on net assimilation and stomatal conductance of some annual Trifolium species of Mediterranean dehesa grasslands were assessed under experimental conditions. Also gas exchange rates were compared between some Leguminosae and Poaceae species growing in the field in a dehesa ecosystem in central Spain. The results showed that the previously reported different O3 sensitivity of some Trifolium species growing in pots does not seem to be related to different maximum g(s) values. In addition, no clear differences on gas exchange rates could be attributed to Leguminosae and Poaceae families growing in the field, with intra-genus variation being more important than differences found between families. Further studies are needed to increase the database for developing a flux-based approach for setting O3 critical levels for semi-natural Mediterranean species.

Biomass↗
PubMed2006

Arrangement and mobility of water in vermiculite hydrates followed by 1H NMR spectroscopy.

The arrangement of water molecules in one- and two-layer hydrates of high-charged vermiculites, saturated with alkaline (Li(+), Na(+)) and alkali-earth (Mg(2+), Ca(2+), Ba(2+)) cations, has been analyzed with (1)H NMR spectroscopy. Two different orientations for water molecules have been found, depending on the hydration state and the sites occupied by interlayer cations. As the amount of water increases, hydrogen bond interactions between water molecules increase at expenses of water-silicate interactions. This interaction favors water mobility in vermiculites. A comparison of the temperature dependence of relaxation times T(1) and T(2) for one and two-layer hydrates of Na-vermiculite shows that the rotations of water molecules around C(2)-axes and that of cation hydration shells around the c-axis is favored in the two-layer hydrate. In both hydrates, the anisotropic diffusion of water takes place at room temperature, preserving the orientation of water molecules relative to the silicate layers. Information obtained by NMR spectroscopy is compatible with that deduced by infrared spectroscopy and with structural studies carried out with X-ray and neutron diffraction techniques on single-crystals of vermiculite.

Aluminum Silicates↗
PubMed2006

Lithium exchange processes in the conduction network of the Nasicon LiTi2-xZrx(PO4)3 Series (0 < or = x < or = 2).

Structural sites occupied by lithium in the rhombohedral LiTi2-xZrx(PO4)3 series (0 < or = x < or = 2) have been investigated by 7Li NMR spectroscopy. At room temperature, the XRD patterns of the end-members of the series display rhombohedral R3c symmetry in LiTi2(PO4)3 and triclinic C in LiZr2(PO4)3. In the first compound, Li ions occupy M1 sites; however, in the second one Li occupy intermediate M1/2 sites. As the temperature increases, a first-order displacive transformation is detected in the triclinic phase, but a second-order/disorder transition is detected in the rhombohedral phase. From the temperature dependence of the 7Li NMR quadrupole constant (CQ) of the two compounds, the evolution of M1 and M1/2 sites occupancy in the Nasicon conduction network has been deduced. At high temperatures, analyzed phases tend toward a disordered rhombohedral phase, in which both M1 and M1/2 sites are equally populated and in which lithium mobility is favored by the existence of vacant M1 sites. According to this study, this phase can also be obtained by substituting Ti by Zr in the LiTi2-xZrx(PO4)3 series.

Letter↗
PubMed2006

Analysis by gas chromatography-mass spectrometry of the volatiles from the fruits of Ammodaucus leucotrichus subsp. leucotrichus and subsp. nanocarpus grown in North Africa and the Canary Islands, respectively.

The volatiles from the fruits of Ammodaucus leucotrichus subsp. leucotrichus and subsp. nanocarpus (two endemic species, the first from North Africa and the second from the Canary Islands, Spain) were studied by gas chromatography and gas chromatography-mass spectrometry. The major components of the volatiles of subsp. nanocarpus were found to be, beta-pinene (22.2-33.6%), bornyl angelate (20.6-21.8%) and camphor (8.3-11.7%) whereas in the fruits of subsp. leucotrichus, the main constituents were perillaldehyde (63.6%) and limonene (26.8%). We also suggest that subsp. nanocarpus should have the status of species and should be named Ammodaucus nanocarpus.

Apiaceae↗
PubMed2006

[Paludism: emergent diagnosis. Descriptive study of 25 cases].

INTRODUCTION: During the last years, the number of patients with paludism in occidental countries has raised, specially due to the increase of immigration from endemic areas and to the augmentation of international journeys to those area. MATERIAL AND METHODS: A descriptive and retrospective study of the cases of paludism diagnosed at the Hospital Universitario La Princesa, was performed between January 1995 and December 2002. RESULT: Twenty-five patients were diagnosed of paludism. More than half of patients (15) were immigrants coming from endemic areas and the rest were Spanish patients who had traveled to endemic places, most of them to Africa. A transfusional case was detected. Twenty-two patients didn't take prophylaxis therapy. The most usual subtype of Plasmodium was P. falciparum. Symptoms were not specific and fever was a constant feature. The period of time between the arrival in spain and the moment of diagnosis range from one to four weeks (21 patients). DISCUSSION: It is important to search for paludism infection in patients with maintained fever who have arrived from tropic regions. Prophylaxis therapy does not exclude this possibility. Response to treatment is usually satisfactory.

Adolescent↗
PubMed2006

Neovascularization in human atherosclerosis.

In the absence of disease, microvessels provide vessel wall nutrients to the tunica media, while the intima is fed by oxygen diffusion from the lumen. As disease evolves and the tunica intima thickens, oxygen diffusion is impaired, and microvessels become the major source for nutrients to the vessel wall. Microvessels serve as a port of entry for inflammatory cells, from the systemic circulation to the nascent atherosclerotic lesion. As disease progress, microvessels also play a role in intraplaque hemorrhage, lipid core expansion, and plaque rupture. In addition, microvessels are also involved in stent restenosis, and plaque regression. Therefore, microvessels are a pivotal component of atherosclerosis, and proper patient risk-stratification in the near future may include the detection of increased neovascularization in atherosclerotic lesions. This review divided in two parts summarizes the current understanding of atherosclerosis neovascularization, starting with the normal anatomy and physiology and progressing to more advanced stages of the disease. We will review the structure and function of vasa vasorum in health and disease, the mechanisms responsible for the angiogenic process, the role of the immune system, including inflammation and Toll-like receptors, and the pathology of microvessels in early atherosclerotic plaques. Furthermore, the review addresses the advanced stages of atherosclerosis, summarizing the progressive role for microvessels during disease progression, red blood cell extravasation, lipid core expansion, plaque rupture, healing, repair, restenosis, and disease regression, offering the clinician a state-of-the-art, "bench to bedside" approach to neovascularization in human atherosclerosis.

Animals↗
PubMed2006

Calcium scoring and contrast-enhanced CT angiography.

Computed tomography (CT) technology has emerged as the most promising imaging modality for the noninvasive evaluation of the coronary circulation. Of the CT-based approaches, multidetector-row computed tomography (MDCT) and to a lesser extent electron beam computed tomography offer the potential of providing not only data on the spatial extent and burden of coronary calcium content, but also angiographic data, and plaque composition characteristics with the potential for prediction of susceptibility to future cardiovascular events. A number of studies have now confirmed that CT-based assessment of the presence and amount of coronary artery calcium provides incremental prognostic information over traditional risk factors in patients with coronary artery disease and can be employed to refine risk stratification in both asymptomatic and symptomatic subjects. With the advent of several recent advances in CT imaging, it is now possible to provide high resolution (sub-millimeter, isotropic voxels) images of the coronary arteries obtained rapidly with iodinated contrast injected peripherally. MDCT is currently the preferred modality for noninvasive contrast angiography of the coronary arteries by most groups, with a new generation of 64-slice scanners promising to further improve the results of this technique. MDCT-derived angiographic information in conjunction with coronary calcium scoring and plaque characterization has the potential of replacing invasive angiography, as it potentially could provide better global assessment of risk.

Calcinosis↗
PubMed2006

Molecular determinants of vascular calcification: a bench to bedside view.

Vascular calcification (VC) is an orchestrated event, evoking the programmed process of the osteogenesis and triggered by inflammatory cytokines active at vascular level. VC is a dynamic process in which the vessel wall intima, media and also cardiac valves may be involved. Intimal calcification is an endochondral ossification process in which type II collagen is mineralized by calcium deposition. In contrast, an intra-membranous ossification process leads to medial calcification, while a dystrophic calcification process is responsible for valvular calcification. Mechanisms involved in VC may be summarized as: 1. Activation of osteogenesis in the vessel wall, 2. Loss of inhibitory factors, 3. Enhanced bone turnover, and 4. Abnormalities in mineral metabolism. The signaling axis constituted by osteoprotegerin (OPG), receptor activator nuclear factor kB (RANK) and its ligand (RANKL), along with the monocyte colony stimulating factor (M-CSF) and the transcription factor core Binding protein (Cbfa-1), play a pivotal role in the control of VC. In contrast, fetuin-A, matrix G1a protein (MGP) and osteopontin (OPN) control the inhibition of VC. In addition, abnormal mineral metabolism with enhanced phosphates availability favors calcium deposition. The inflammatory cytokines interleukin (IL-1) and tumor necrosis factor (TNF)-alpha enhance OPG and RANKL function in the vessel wall leading to VC. VC is a controlled process, depending on the balance between osteoblastic and osteoclastic influences and further modulated by the influence of risk factors like diabetes, smoking, age, hypertension and dyslipidemia. Recent advances in diagnostic tools such as with multi-detector computed tomography (MDCT) and electron beam computed tomography (EBCT), may help diagnosis and delineation of VC in the clinical setting and aid in understanding its prognostic value.

Animals↗
PubMed2006

Atherosclerosis neovascularization and imaging.

Neovascularization in atherosclerotic plaques is particularly prominent in complicated lesions, and has been recently identified as a marker of plaque vulnerability. This observation has led to a growing interest in the development of imaging techniques with the ability to visualize and quantify the extent of plaque neovascularization. Such feature may play an important role in identifying those lesions more prone to destabilization and rupture, and in the guidance and monitoring of therapeutic interventions. Several modalities have emerged as potential candidates for imaging neovessels in atherosclerotic lesions. They include magnetic resonance imaging, x-ray computed tomography, positron emission tomography, single photon emission computed tomography, ultrasound, or near-infrared optical imaging. These techniques differ in their achievable spatial and temporal resolution, availability, cost, reproducibility, degree of intrusiveness, capability to image atherosclerotic plaques in various vascular territories and ability to discern different plaque components, specifically the presence of neovessels. Molecular imaging, a rapidly evolving multidisciplinary field devoted to the visualization of specific physiopathologic processes at the cellular or molecular level, appears particularly well suited for this purpose because of its ability to target and visualize individual molecules specific to neoangiogenesis. In this manuscript we will review current evidence on the potential application of the various modalities, with a particular emphasis in molecular imaging.

Animals↗
PubMed2006

[Recurrence of peripheral primitive neuroectodermal tumor of the orbit with systemic metastases].

CASE REPORT: A six-year-old boy presented with proptosis of the right eye. Imaging studies detected a mass in the medial wall of the right orbit. This mass was biopsied revealing a histopathologic diagnosis of primitive neuroectodermal tumor, so chemotherapy treatment was given. After seven years in remission he presented with a recurrence of the orbital tumor and was found to also have systemic metastases. Treatment with chemotherapy, radiotherapy and orbital exenteration was unsuccessful. DISCUSSION: The orbital occurrence of these tumors is extremely rare. Differentiation from other small round cell tumors requires immunohistochemical and ultrastructural techniques.

Child↗
PubMed2005

Influence of reduction conditions on H2 adsorption in high-surface Rh/CeO2 catalysts as deduced by volumetry, calorimetry, and 1H NMR techniques.

1H NMR spectra corresponding to H2 adsorption on high-surface Rh/CeO2 catalysts (S(BET) approximately 55 m2/g) are formed by two lines, attributed to hydrogen adsorbed on ceria (resonance line A) and rhodium-metal particles (upfield-shifted line B). The evolution of 1H NMR spectra as a function of temperature, time, and type of reduction (static or dynamic) allows the study of the progressive establishment of the strong metal-support interaction (SMSI) in Rh/CeO2 catalysts. As the reduction progresses, the mean adsorption heat and the amount of hydrogen adsorbed on the metal, deduced from volumetry, NMR, and calorimetry techniques, decrease considerably. As a consequence of the decrease in metal activity, the amount of hydrogen transferred to the support CeO2 is also reduced (spill-over processes). Outgassing of samples at 773 K eliminates hydrogen species retained at the metal-support surface, and oxidation treatments at 473 and 673 K eliminate the electronic effect and physical blocking of metal particles. The oxidation at 673 K recuperates the total adsorption capacity of metal particles. On the basis of these treatments, the contribution of different processes to the SMSI effect is analyzed. Electronic perturbation of rhodium particles is higher when reductions are performed in dynamic conditions; however, the importance of physical blocking of metal particles increases in static reductions. High reducibility of ceria strengthens electronic effects in Rh/CeO2 compared to those observed in Rh/TiO2 catalysts.

Journal Article↗
PubMed2005

Analysis by gas chromatography-mass spectrometry of the essential oils from the aerial parts of Pimpinella anagodendron Bolle and Pimpinella rupicola Svent., two endemic species to the Canary Islands, Spain.

The essential oils from the aerial parts of Pimpinella anagodendron Bolle and Pimpinella rupicola Svent., two endemic species growing in Tenerife, Canary Islands, Spain, were studied by gas chromatography and gas chromatography-mass spectrometry. The major components of the flowering tops (flowers+unripe fruits) of P. rupicola (PRFT) were found to be beta-bisabolene (34.8%), limonene (10.9%) and alpha-zingiberene (10.5%), whereas in the flowering tops of P. anagodendron (PAFT), the main constituents were alpha-zingiberene (32.9%), beta-bisabolene (17.9%), beta-pinene (15.8%) and ar-curcumene (11.5%). The major compounds found in the stems+leaves of P. rupicola (PRSL) were beta-bisabolene (31.6%), alpha-zingiberene (11.4%) and limonene (10.8%), whereas those of P. anagodendron (PASL) were alpha-zingiberene (32.3%), beta-bisabolene (14.0%) and ar-curcumene (12.6%). In all the oils were found the characteristic constituents of genus Pimpinella, the pseudoisoeugenol esters. In accordance with the morphological, chorological and chemical differences between both species, we suggest that P. rupicola Svent. is a good taxon and not a synonym of P. anagodendron.

Chromatography, Gas↗
PubMed2005

Postoperative changes of carpal canal pressure in carpal tunnel syndrome: a prospective study with follow-up of 1 year.

Carpal canal pressures were measured in 103 patients with idiopathic carpal tunnel syndrome, before and after open release, with a postoperative follow-up of 1 year. Twenty-five normal subjects were used as controls. Pressures were measured with the wrists in three positions: neutral, full passive flexion and full passive extension. At each wrist position, the mean pre-operative pressures in the study group were significantly higher than in the control group. In both groups, the pressures were maximal with full passive extension and minimal in the neutral wrist position. Immediately after surgical release, there was a marked decrease of the carpal canal pressures. However, during the second postoperative month, there was a significant increase of the pressures at each wrist position, although these were still within the normal control range. This rise in pressures persisted to 12 months. These findings suggest that the carpal ligament reconstitutes by normal scar formation, but with lengthening such that the volume of the carpal canal is enlarged, so preventing a rise in pressure with return of the pre-operative problem.

Adult↗