140 research outputs found

    On the de Haas - van Alphen oscillations in quasi-two-dimensional metals: effect of the Fermi surface curvature

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    Here, we present the results of theoretical analysis of the de Haas-van Alphen oscillations in quasi-two-dimensional normal metals. We had been studying effects of the Fermi surface (FS) shape on these oscillations. It was shown that the effects could be revealed and well pronounced when the FS curvature becomes zero at cross-sections with extremal cross-sectional areas. In this case both shape and amplitude of the oscillations could be significantly changed. Also, we analyze the effect of the FS local geometry on the angular dependencies of the oscillation amplitudes when the magnetic field is tilted away from the FS symmetry axis by the angle θ.\theta. We show that a peak appears at θ0\theta \approx 0 whose height could be of the same order as the maximum at the Yamaji angle. This peak emerges when the FS includes zero curvature cross-sections of extremal areas. Such maximum was observed in experiments on the α(BETS)4TIHg(SeCN)4.\alpha-(BETS)_4TIHg(SeCN)_4. The obtained results could be applied to organic metals and other quasi-two-dimensional compounds.Comment: 9 pages, 4 figures, text added, references adde

    Total urinary polyphenols and longitudinal changes of bone properties. The InCHIANTI study

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    SummaryThe aim of this study was to evaluate the association of levels of urinary total polyphenols considered as a proxymeasure of polyphenol intake, with longitudinal changes of bone properties, in the InCHIANTI study. Dietary intake ofpolyphenols appears to be associated with future accelerated deterioration of bone health.IntroductionPolyphenols, micronutrients ingested through plant-based foods, have antioxidant and anti-inflammatory propertiesand may contribute to osteoporosis prevention. We evaluated associations of high levels of urinary total polyphenols (UTP), aproxy measure of polyphenol intake, with longitudinal changes of bone properties in a representative cohort of free-livingparticipants of the InCHIANTI study.MethodsThe InCHIANTI study enrolled representative samples from the registry list of two towns in Tuscany, Italy. Baselinedata were collected in 1998 and follow-up visits in 2001 and 2004. Of the 1453 participants enrolled, 956 consented to donate a24-h urine sample used to assess UTP, had dietary assessment, a physical examination, and underwent a quantitative comput-erized tomography (pQCT) of the tibia. From pQCT images, we estimated markers of bone mass (BM), diaphyseal design (DD),and material quality (MQ). Mixed models were used to study the relationship between baseline tertiles of UTP with changes ofthe bone characteristics over the follow-up.ResultsAt baseline, higher levels of UTP were positively correlated with markers of BM, DD, and MQ. Compared with lowertertile of UTP, participants in the intermediate and highest tertiles had higher cortical bone area, cortical mineral content, andcortical thickness. However, participants in the intermediate and highest UTP tertiles experienced accelerated deterioration ofthese same parameters over the follow-up compared with those in the lowest UTP tertile.ConclusionsDietary intake of polyphenols estimated by UTP and dietary questionnaire was associated with long-term acceler-ated deterioration of bone health. Our study does not support the recommendation of increasing polyphenol intake for osteopo-rosis prevention

    Effect of a polyphenol-rich dietary pattern on intestinal permeability and gut and blood microbiomics in older subjects: study protocol of the MaPLE randomised controlled trial.

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    BACKGROUND: During aging, alterations of the intestinal microbial ecosystem can occur contributing to immunosenescence, inflamm-aging and impairment of intestinal barrier function (increased intestinal permeability; IP). In the context of a diet-microbiota-IP axis in older subjects, food bioactives such as polyphenols may play a beneficial modulatory role. METHODS: MaPLE is a project centered on a randomized, controlled cross-over dietary intervention trial [polyphenol-rich diet (PR-diet) versus control diet (C-diet)] targeted to older people ( 65 60 y) living in a well-controlled setting (i.e. nursing home). The 8-week interventions are separated by an 8-week wash-out period. Three small portions per day of selected polyphenol-rich foods are consumed during intervention in substitution of other comparable products within the C-diet. Biological samples are collected before and after each treatment period to evaluate markers related to IP, inflammation, vascular function, oxidative stress, gut and blood microbiomics, metabolomics. A sample size of 50 subjects was defined based on IP as primary outcome. DISCUSSION: Evidence that increasing the consumption of polyphenol-rich food products can positively affect intestinal microbial ecosystem resulting in reduced IP and decreased translocation of inflammogenic bacterial factors into the bloodstream will be provided. The integration of data from gut and blood microbiomics, metabolomics and other IP-related markers will improve the understanding of the beneficial effect of the intervention in the context of polyphenols-microbiota-IP interactions. Finally, findings obtained will provide a proof of concept of the reliability of the dietary intervention, also contributing to future implementations of dietary guidelines directed to IP management in the older and other at risk subjects. TRIAL REGISTRATION: The trial is registered at (ISRCTN10214981); April 28, 2017

    Correlation between the findings in the first post-transplantation Renogram and the allograft renal function twelve months after surgery

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    EP-061 Aim/Introduction: To study the correlation between findings in the first renogram post-trasplantation, and the evolution of the renal function of the graft twelve months after surgery. Materials and Methods: 20-minute duration renogram with [99mTc]Tc-MAG3, performed in the first 72 hours post-kidney transplantation, of patients attended at the Nuclear Medicine Service between January-December of 2018 are reviewed, extracting: a) the concentration angle (CA) that measures the inclination of the ascent section of the concentration phase with respect to the vertical axis (cutoff thershold <40° vs =40°); b) the time, in minutes (Tmax), at which the maximum concentration occurs (<10 vs =10min); and c) the percentage of cortical retention (CR) at the end of the study (<80% vs =80%). These 3 parameters are correlated with renal function at 12 months post-transplantation, through the need or not of dialysis. Results: A total of 62 renograms were obtained, excluding 7 due to death as a result of intercurrent diseases and 2 due to vascular complications and graft loss, before the first year after surgery. 53 patients, 15 female and 38 male, aged between 20-80 years, were included in the analysis. Functional failure (dialysis) of the graft one year after the transplantation ocurred in 15% (8/53). In patients with CA =40° the probability of failure was 28% (5/18) and in CA <40° 8.6% (3/35), with relative risk (RR) of 3.2. 7/34 (20, 6%) patients incluided in the group with Tmax =10 min were on dialysis one-year after, unlike just 1/19 (5, 3%) if Tmax<10min (RR 3, 8). Among the 37 patients with CR =80%, 8/37 (22%) were dialyzed one year after, while none of the 16 in the group of patients with CR <80% (0% probability if CR <80%). The matching of parameteres CA =40°, Tmax =10 min and CR =80% together do not improve the prediction of dialysis one year after (27%, 5/18). Conclusion: 1. Renogram parameters 72 hours post-transplantation, such as concentration phase angle =40°, time at maximun concentration =10min and percentage of cortical retention =80%, allow recognize a group of patients with greater probability of needing dialysis in the first year after surgery, but they do not are capable of indentify in which specific patients it will occur. 2. The parameter that best predicts the viability of the graft is cortical retention <80%

    Predictors Of Positivity Of [F-18]F-Choline PET-CT In Prostate Cancer Recurrence. Preliminary Results

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    EP-173 Aim/Introduction: To analyze the validity of [18F]F-Choline PET-CT results in prostate cancer recurrence in our daily practice, based on theoretical cut-off points of prostatespecific antigen (PSA), its kinetic, and PSA doubling time (PSADT), to identify predictors of positivity and modify the indication criteria. Materials and Methods: Prior to the validity analysis, a descriptive, prospective analysis of consecutive patients with prostate cancer treated with curative intent by radical prostatectomy (RP) or radiotherapy (RT), who underwent PET-CT scan with recurrence criteria: PSA =1 or PSA 0.4-1 with PSADT Nadir + 2 after RT, was performed. Results: From April to December 2019, 69 patients were included, 40 were treated with RP (58%) and 29 with RT (42%). In 45 patients (65%) PET-CT was able to identify recurrence of the disease (positive PET) and in 24 it was not (negative PET). Of patients treated with RP, 82, 5% (33/40) had PSA>1, and of those, 61% were positive PET. 17, 5% (7/40) had PSA6months (28/69), in 71% if PSADT6 months, in 61% and 92% if PSADT<6 months and in 77% and 100% if PSADT<3 months. Conclusion: Preliminarily and awaiting validation, it seems that PSA>1 after RP or Nadir +2 after RT is an indicator of PET-CT. There seems to be a tendency that shows that PSA<1 after RP is an indicator of PET-CT if PSADT<3 months. PSADT <3 or <6 months could be the best predictor of positivity of PET-CT with [18F]F-Choline in recurrent prostate cancer

    Analysis of results of effective dose estimation obtained from RADAR 2017 dose assessment model for nuclear medicine procedures

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    EP-296 Aim/Introduction: To analyze the results of effective dose (E) estimation of the most frequent procedures using photon emitters in Nuclear Medicine, obtained from RADAR 2017 dose assessment model. To compare these results with those obtained from ICRP 128 (2015) recommendations, and to assess how using each dose assessment model can change E results. Materials and Methods: E estimation data was collected from photon emitter procedures performed during the last year in our department, obtained from RADAR 2017 dose estimation model for age groups: = 1 year old; >1-5 years old ; >5- 10 years old, >10- 15 years old and adults. Injected activity was the one recommended by international guidelines and EANM Pediatric and Dosimetry Committees. Hybrid exams (SPECT / CT) and procedures for which there is no RADAR 2017 dosimetry estimation were excluded. Results for (E) were compared with those obtained by using ICRP 128 (2015) recommendations. Results: With RADAR 2017 dose evaluation model we obtained a lower mean value of E on most of the procedures that were analyzed, being significantly lower for Renogram, Renal scintigraphy on >10-15 years old, Thyroid scintigraphy, Meckel’s scan and Bone Scan (0.12 to 1.16 mSv, 25% to 67%). Brain perfusion and Renal scintigraphy on ages under 10 obtained a significantly greater difference for E (0.33 to 2.85 mSv, 26% to 29%). Conclusion: These results are an updated collection of estimated E values for photon-emitting radiopharmaceuticals commonly used in Nuclear Medicine, considering RADAR 2017 dose assessment model compared to ICRP 128) recommendations. Methodological changes on estimation lead to lower E for most of diagnostic procedures using photon emitters, this is of special interest for patients undergoing repeated ionizing radiation (dosimetry history)

    ¿Cómo diseñar, aplicar y evaluar un programa de Mentoring en enfermedad renal crónica? evaluación narrativa del impacto en 6 centros asistenciales

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    Antecedentes y objetivo La enfermedad renal crónica (ERC) requiere de un proceso de adaptación en el paciente, que se puede facilitar con el apoyo de los profesionales sanitarios, así como por iguales capacitados. El objetivo de este estudio es presentar la puesta en marcha de un programa piloto de paciente mentor para promover la adaptación de los pacientes con ERC. Materiales y método Diseño mixto (cuantitativo y cualitativo) pre-post. El estudio se llevó a cabo en 6 hospitales de España. Los instrumentos utilizados para medir el impacto fueron escalas elaboradas ad-hoc (formato de respuesta escala de Likert de 10 puntos) de satisfacción y adquisición de competencias, así como la creación de grupos focales con 8 pacientes mentores y 10 profesionales sanitarios. Se dividió el programa en 4 fases: 1) Diseño y validación de contenidos del programa manualizado y selección de pacientes mentores; 2) Formación a mentores, satisfacción con la formación y competencias adquiridas por los mentores; 3) Implementación de los grupos de apoyo mutuo y perfil de los asistentes a los grupos de apoyo mutuo, y 4) Evaluación y resultados del programa de Mentoring. Resultados Se han formado a un total de 39 mentores en habilidades para conducción de grupos, así como para facilitar apoyo emocional. Se han conducido 22 grupos de apoyo con 121 participantes (22% cuidadores). El 65% de los pacientes estaban en consulta de ERC. Un 65% de los pacientes participantes consideraron hacer algún cambio en su estilo de vida tras la asistencia al programa. Todos los ítems que evalúan satisfacción y utilidad han mostrado una puntuación muy elevada, por encima del valor 8, 5 sobre 10. Conclusiones Este es el primer programa manualizado de Mentoring en ERC llevado a cabo de manera simultánea en 6 hospitales españoles. La naturaleza del programa, manualizado y altamente estructurado, permite su replicabilidad minimizando el riesgo de error. Background and objective Chronic kidney disease (CKD) requires patients to participate in an adaptation process, which may be facilitated with the support of healthcare professionals and trained peers. The objective of this study is to present the implementation of a pilot patient mentoring programme to promote adaptation in patients with CKD. Materials and method Pre-test-post-test design (quantitative and qualitative). The study was carried out in six hospitals in Spain. The instruments used to measure impact were ad-hoc scales (10-point Likert scale response format) on satisfaction and skill acquisition, as well as the creation of focus groups with eight patient mentors and 10 healthcare professionals. The programme was split into four phases: 1. Design and validation of the manualised programme''s content, and selection of patient mentors; 2. Mentor training, satisfaction with training and skills acquired by the mentors; 3. Implementation of mutual support groups and profile of those attending these mutual support groups; 4. Assessment and results of the Mentoring programme. Results In total, 39 mentors were trained on group management skills, as well as how to provide emotional support. 22 support groups were held, with 121 participants (22% carers). The 65% of the patients were attending the CKD clinic. 65% of the participating patients considered making some form of lifestyle change after taking part in the programme. All the items assessing satisfaction and usefulness scored very highly, achieving 8.5 out of 10 or above. Conclusions This is the first manualised mentoring programme in CKD to be undertaken simultaneously in six Spanish hospitals. The manualised and highly structured nature of the programme make it easy to replicate, minimising the risk of error

    TGFBR1 Intralocus Epistatic Interaction as a Risk Factor for Colorectal Cancer

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    In colorectal cancer (CRC), an inherited susceptibility risk affects about 35% of patients, whereas high-penetrance germline mutations account for <6% of cases. A considerable proportion of sporadic tumors could be explained by the coinheritance of multiple low-penetrance variants, some of which are common. We assessed the susceptibility to CRC conferred by genetic variants at the TGFBR1 locus. We analyzed 14 polymorphisms and the allele-specific expression (ASE) of TGFBR1 in 1025 individuals from the Spanish population. A case-control study was undertaken with 504 controls and 521 patients with sporadic CRC. Fourteen polymorphisms located at the TGFBR1 locus were genotyped with the iPLEX Gold (MassARRAY-Sequenom) technology. Descriptive analyses of the polymorphisms and haplotypes and association studies were performed with the SNPator workpackage. No relevant associations were detected between individual polymorphisms or haplotypes and the risk of CRC. The TGFBR1*9A/6A polymorphism was used for the ASE analysis. Heterozygous individuals were analyzed for ASE by fragment analysis using cDNA from normal tissue. The relative level of allelic expression was extrapolated from a standard curve. The cutoff value was calculated with Youden's index. ASE was found in 25.4% of patients and 16.4% of controls. Considering both bimodal and continuous types of distribution, no significant differences between the ASE values of patients and controls were identified. Interestingly, a combined analysis of the polymorphisms and ASE for the association with CRC occurrence revealed that ASE-positive individuals carrying one of the most common haplotypes (H2: 20.7%) showed remarkable susceptibility to CRC (RR: 5.25; 95% CI: 2.547–5.250; p<0.001) with a synergy factor of 3.7. In our study, 54.1% of sporadic CRC cases were attributable to the coinheritance of the H2 haplotype and TGFBR1 ASE. These results support the hypothesis that the allelic architecture of cancer genes, rather than individual polymorphisms, more accurately defines the CRC risk

    Nutrimetabolomics: An Integrative Action for Metabolomic Analyses in Human Nutritional Studies

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    The life sciences are currently being transformed by an unprecedented wave of developments in molecular analysis, which include important advances in instrumental analysis as well as biocomputing. In light of the central role played by metabolism in nutrition, metabolomics is rapidly being established as a key analytical tool in human nutritional studies. Consequently, an increasing number of nutritionists integrate metabolomics into their study designs. Within this dynamic landscape, the potential of nutritional metabolomics (nutrimetabolomics) to be translated into a science, which can impact on health policies, still needs to be realized. A key element to reach this goal is the ability of the research community to join, to collectively make the best use of the potential offered by nutritional metabolomics. This article, therefore, provides a methodological description of nutritional metabolomics that reflects on the state‐of‐the‐art techniques used in the laboratories of the Food Biomarker Alliance (funded by the European Joint Programming Initiative "A Healthy Diet for a Healthy Life" (JPI HDHL)) as well as points of reflections to harmonize this field. It is not intended to be exhaustive but rather to present a pragmatic guidance on metabolomic methodologies, providing readers with useful "tips and tricks" along the analytical workflow
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