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1.
Rheumatol Int ; 35(5): 855-9, 2015 May.
Artículo en Inglés | MEDLINE | ID: mdl-25510289

RESUMEN

Our objective was to analyze the effects of cigarette smoking on disease activity, functional capacity, radiographic damage, serology and presence of extraarticular manifestations in patients with rheumatoid arthritis and undifferentiated arthritis. This is a cross-sectional study of 1,305 patients (729 with rheumatoid arthritis and 576 with undifferentiated arthritis) from CONAART, the Argentine Consortium for Early Arthritis that includes patients older than 16 years with <2 years of disease. Sociodemographic data, clinical characteristics of the disease and smoking history were collected. In patients with rheumatoid arthritis the disease activity score of 28 joints was 5.4 ± 1.3 in current smokers, 5.2 ± 1.4 in former smokers and 5.1 ± 1.4 in never smokers (p = 0.011). The simple erosion narrowing score was higher in current smokers and former smokers than in never smokers (M 14.0, R Q 6.0-21.0; M 15.0, R Q 7.0-24.0; M 10.0, R Q 5.0-17.0; p = 0.006). Current smokers had higher rheumatoid factor titer (M 160.0, R Q 80.0-341.0) than former smokers (M 146.8, R Q 6.03-255.5) and never smokers (M 15.0, R Q 9.0-80.0) (p = 0.004). The variable independently associated with tobacco exposure was simple erosion narrowing score (OR = 1.03, 95 % CI 1.00-1.05; p = 0.012). In patients with undifferentiated arthritis, an association between smoking status and parameters of activity or radiographic damage was not observed. Neither was tobacco exposure related to the presence of extraarticular manifestations or to the degree of disability in any of the two groups of patients. No relation was found between disease activity and severity, and number of packs smoked per year. Tobacco.


Asunto(s)
Artritis Reumatoide/epidemiología , Articulaciones del Pie/diagnóstico por imagen , Articulaciones de la Mano/diagnóstico por imagen , Fumar/epidemiología , Adulto , Factores de Edad , Anciano , Argentina/epidemiología , Artritis/diagnóstico por imagen , Artritis/epidemiología , Artritis/inmunología , Artritis Reumatoide/diagnóstico por imagen , Artritis Reumatoide/inmunología , Sedimentación Sanguínea , Proteína C-Reactiva/inmunología , Estudios Transversales , Femenino , Humanos , Masculino , Persona de Mediana Edad , Radiografía , Factor Reumatoide/inmunología , Factores de Riesgo , Índice de Severidad de la Enfermedad , Factores Sexuales , Fumar/inmunología
2.
Rheumatology (Oxford) ; 53(8): 1431-8, 2014 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-24633413

RESUMEN

OBJECTIVES: The aim of this study was to assess the cumulative incidence, risk and protective factors and impact on mortality of primary cardiac disease in SLE patients (disease duration ≤2 years) from a multi-ethnic, international, longitudinal inception cohort (34 centres, 9 Latin American countries). METHODS: Risk and protective factors of primary cardiac disease (pericarditis, myocarditis, endocarditis, arrhythmias and/or valvular abnormalities) were evaluated. RESULTS: Of 1437 patients, 202 (14.1%) developed one or more manifestations: 164 pericarditis, 35 valvulopathy, 23 arrhythmias, 7 myocarditis and 1 endocarditis at follow-up; 77 of these patients also had an episode of primary cardiac disease at or before recruitment. In the multivariable parsimonious model, African/Latin American ethnicity [odds ratio (OR) 1.80, 95% CI 1.13, 2.86], primary cardiac disease at or before recruitment (OR 6.56, 95% CI 4.56, 9.43) and first SLICC/ACR Damage Index for SLE assessment (OR 1.31, 95% CI 1.14, 1.50) were risk factors for the subsequent occurrence of primary cardiac disease. CNS involvement (OR 0.44, 95% CI 0.25, 0.75) and antimalarial treatment (OR 0.62, 95% CI 0.44, 0.89) at or before recruitment were negatively associated with the occurrence of primary cardiac disease risk. Primary cardiac disease was not independently associated with mortality. CONCLUSION: Primary cardiac disease occurred in 14.1% of SLE patients of the Grupo Latino Americano de Estudio de Lupus cohort and pericarditis was its most frequent manifestation. African origin and lupus damage were found to be risk factors, while CNS involvement at or before recruitment and antimalarial treatment were protective. Primary cardiac disease had no impact on mortality.


Asunto(s)
Cardiopatías/epidemiología , Lupus Eritematoso Sistémico/epidemiología , Edad de Inicio , Anciano , Causas de Muerte , Comorbilidad , Femenino , Cardiopatías/mortalidad , Humanos , Incidencia , América Latina/epidemiología , Lupus Eritematoso Sistémico/mortalidad , Masculino , Persona de Mediana Edad , Factores de Riesgo , Índice de Severidad de la Enfermedad
3.
Arthritis Rheum ; 65(6): 1457-67, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23460240

RESUMEN

OBJECTIVE: To identify susceptibility loci for rheumatoid arthritis (RA) in Latin American individuals with admixed European and Amerindian genetic ancestry. METHODS: Genotyping was performed in 1,475 patients with RA and 1,213 control subjects, using a customized BeadArray containing 196,524 markers covering loci previously associated with various autoimmune diseases. Principal components analysis (EigenSoft package) and Structure software were used to identify outliers and define the population substructure. REAP software was used to define cryptic relatedness and duplicates, and genetic association analyses were conducted using Plink statistical software. RESULTS: A strong genetic association between RA and the major histocompatibility complex region was observed, localized within BTNL2/DRA-DQB1- DQA2 (P = 7.6 × 10(-10) ), with 3 independent effects. We identified an association in the PLCH2-HES5-TNFRSF14-MMEL1 region of chromosome 1 (P = 9.77 × 10(-6) ), which was previously reported in Europeans, Asians, and Native Canadians. We identified one novel putative association in ENOX1 on chromosome 13 (P = 3.24 × 10(-7) ). Previously reported associations were observed in the current study, including PTPN22, SPRED2, STAT4, IRF5, CCL21, and IL2RA, although the significance was relatively moderate. Adjustment for Amerindian ancestry improved the association of a novel locus in chromosome 12 at C12orf30 (NAA25) (P = 3.9 × 10(-6) ). Associations with the HLA region, SPRED2, and PTPN22 improved in individuals positive for anti-cyclic citrullinated peptide antibodies. CONCLUSION: Our data define, for the first time, the contribution of Amerindian ancestry to the genetic architecture of RA in an admixed Latin American population by confirming the role of the HLA region and supporting the association with a locus in chromosome 1. In addition, we provide data for novel putative loci in chromosomes 12 and 13.


Asunto(s)
Artritis Reumatoide/genética , Cromosomas Humanos Par 12/genética , Cromosomas Humanos Par 13/genética , Cromosomas Humanos Par 1/genética , Antígenos HLA/genética , Femenino , Genotipo , Humanos , Indígenas Sudamericanos , América Latina , Masculino , Análisis de Secuencia por Matrices de Oligonucleótidos
4.
Cranio ; 32(1): 31-7, 2014 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-24660644

RESUMEN

AIMS: Temporomandibular joint (TMJ) and stomatognathic system involvement are usually observed during the course of rheumatoid arthritis. METHODOLOGY: This article presents the findings during examination of 190 TMJs from rheumatoid arthritis (RA) patients, and 44 TMJs from controls without RA, including a description of signs and symptoms related to the stomatognathic system, radiological findings in hands-, and TMJ, erythrocyte sedimentation rate (ESR) values, and scores obtained in the Disease Activity Score (Das 28) and the Health Assessment Questionnaire (HAQ). RESULTS: The sample included 57.89% TMJs associated with spontaneous pain, 87.89% with signs of destruction in radiological images, and 58.94% with 20 teeth or less. Restricted mouth opening was detected in 42.1% of RA patients, from which 71% had blocked opening; headache was present in 58%, and pain in the masticatory muscles was found in 57%. TMJ erosions had a significant association with Larsen scores (r=0.62), but not with the Das 28, HAQ, and ESR values. CONCLUSIONS: The early evaluation of this joint and the collaborative work of odontologists and rheumatologists are both necessary for a better management of TMJ pathologies.


Asunto(s)
Artritis Reumatoide/complicaciones , Dolor Facial/etiología , Trastornos de la Articulación Temporomandibular/etiología , Adulto , Anciano , Artritis Reumatoide/fisiopatología , Estudios de Casos y Controles , Femenino , Huesos de la Mano/diagnóstico por imagen , Huesos de la Mano/patología , Cefalea/etiología , Humanos , Masculino , Músculos Masticadores/fisiopatología , Persona de Mediana Edad , Radiografía , Rango del Movimiento Articular , Estudios Retrospectivos , Estadísticas no Paramétricas , Encuestas y Cuestionarios , Articulación Temporomandibular/diagnóstico por imagen , Articulación Temporomandibular/patología , Trastornos de la Articulación Temporomandibular/diagnóstico por imagen , Trastornos de la Articulación Temporomandibular/fisiopatología , Adulto Joven
5.
Genes (Basel) ; 15(4)2024 04 09.
Artículo en Inglés | MEDLINE | ID: mdl-38674407

RESUMEN

Multidrug resistance (MDR) commonly leads to cancer treatment failure because cancer cells often expel chemotherapeutic drugs using ATP-binding cassette (ABC) transporters, which reduce drug levels within the cells. This study investigated the clinical characteristics and single nucleotide variant (SNV) in ABCB1, ABCC1, ABCC2, ABCC4, and ABCG2, and their association with mortality in pediatric patients with central nervous system tumors (CNST). Using TaqMan probes, a real-time polymerase chain reaction genotyped 15 SNPs in 111 samples. Patients were followed up until death or the last follow-up day using the Cox proportional hazards model. An association was found between the rs1045642 (ABCB1) in the recessive model (HR = 2.433, 95% CI 1.098-5.392, p = 0.029), and the ICE scheme in the codominant model (HR = 9.810, 95% CI 2.74-35.06, p ≤ 0.001), dominant model (HR = 6.807, 95% CI 2.87-16.103, p ≤ 0.001), and recessive model (HR = 6.903, 95% CI 2.915-16.544, p = 0.038) significantly increased mortality in this cohort of patients. An association was also observed between the variant rs3114020 (ABCG2) and mortality in the codominant model (HR = 5.35, 95% CI 1.83-15.39, p = 0.002) and the dominant model (HR = 4.421, 95% CI 1.747-11.185, p = 0.002). A significant association between the ICE treatment schedule and increased mortality risk in the codominant model (HR = 6.351, 95% CI 1.831-22.02, p = 0.004, HR = 9.571, 95% CI 2.856-32.07, p ≤ 0.001), dominant model (HR = 6.592, 95% CI 2.669-16.280, p ≤ 0.001), and recessive model (HR = 5.798, 95% CI 2.411-13.940, p ≤ 0.001). The genetic variants rs3114020 in the ABCG2 gene and rs1045642 in the ABCB1 gene and the ICE chemotherapy schedule were associated with an increased mortality risk in this cohort of pediatric patients with CNST.


Asunto(s)
Neoplasias del Sistema Nervioso Central , Proteína 2 Asociada a Resistencia a Múltiples Medicamentos , Polimorfismo de Nucleótido Simple , Humanos , Masculino , Femenino , Niño , Preescolar , Lactante , Neoplasias del Sistema Nervioso Central/genética , Neoplasias del Sistema Nervioso Central/mortalidad , Neoplasias del Sistema Nervioso Central/patología , Estudios de Cohortes , Adolescente , Proteínas Asociadas a Resistencia a Múltiples Medicamentos/genética , Transportador de Casetes de Unión a ATP, Subfamilia G, Miembro 2/genética , Marcadores Genéticos/genética , Proteínas de Neoplasias/genética , Subfamilia B de Transportador de Casetes de Unión a ATP/genética , Biomarcadores de Tumor/genética
6.
Enferm Infecc Microbiol Clin ; 31(3): 159-72, 2013 Mar.
Artículo en Español | MEDLINE | ID: mdl-22658283

RESUMEN

Group B streptococci (GBS) remain the most common cause of early onset neonatal sepsis. In 2003 the Spanish Societies of Obstetrics and Gynaecology, Neonatology, Infectious Diseases and Clinical Microbiology, Chemotherapy, and Family and Community Medicine published updated recommendations for the prevention of early onset neonatal GBS infection. It was recommended to study all pregnant women at 35-37 weeks gestation to determine whether they were colonised by GBS, and to administer intrapartum antibiotic prophylaxis (IAP) to all colonised women. There has been a significant reduction in neonatal GBS infection in Spain following the widespread application of IAP. Today most cases of early onset GBS neonatal infection are due to false negative results in detecting GBS, to the lack of communication between laboratories and obstetric units, and to failures in implementing the prevention protocol. In 2010, new recommendations were published by the CDC, and this fact, together with the new knowledge and experience available, has led to the publishing of these new recommendations. The main changes in these revised recommendations include: microbiological methods to identify pregnant GBS carriers and for testing GBS antibiotic sensitivity, and the antibiotics used for IAP are updated; The significance of the presence of GBS in urine, including criteria for the diagnosis of UTI and asymptomatic bacteriuria in pregnancy are clarified; IAP in preterm labour and premature rupture of membranes, and the management of the newborn in relation to GBS carrier status of the mother are also revised. These recommendations are only addressed to the prevention of GBS early neonatal infection, are not effective against late neonatal infection.


Asunto(s)
Infecciones Estreptocócicas/prevención & control , Streptococcus agalactiae , Profilaxis Antibiótica , Árboles de Decisión , Femenino , Humanos , Recién Nacido , Transmisión Vertical de Enfermedad Infecciosa/prevención & control , Embarazo , Complicaciones Infecciosas del Embarazo/diagnóstico , Complicaciones Infecciosas del Embarazo/prevención & control , España , Infecciones Estreptocócicas/diagnóstico , Infecciones Estreptocócicas/terapia
7.
CNS Neurol Disord Drug Targets ; 22(5): 634-642, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-35579144

RESUMEN

BACKGROUND: Medulloblastomas (MB) are the most common malignant brain tumors in the pediatric age. In 2021, WHO categorized medulloblastomas into two groups: molecularly defined and histologically defined medulloblastomas. Molecularly defined medulloblastomas are divided into WNTactivated medulloblastoma, SHH-activated and TP53-wildtype medulloblastoma, SHH-activated, and TP53-mutant and non-WNT/non-SHH medulloblastoma, which include Group 3 (MYC) and Group 4 (CDK6 and MYCN). In this paper, we will focus on molecularly defined medulloblastomas. OBJECTIVE: This paper aims to review the literature in order to describe the molecular structure of the medulloblastoma groups and to emphasize the importance of genetic predictors in medulloblastoma that can be used in clinical practice, either as a prognostic tool or as a therapeutic target in the future. RESULTS: Each molecular subtype of medulloblastoma presents a different prognosis, and the molecular subtype with the best prognosis is medulloblastoma-activated WNT. It has even been observed that a reduction in the intensity of the combined treatment does not modify the prognosis of the patients, resulting in even fewer adverse effects due to the treatment. On the other hand, it was observed that the subtypes with the worst prognosis are medulloblastomas with activated MYC and medulloblastomas with activated SHH and mutated TP53, due to their high capacity to metastasize or to their radio-resistance. However, a new target therapy has emerged that could help improve the prognosis in these patients. CONCLUSION: The deeper knowledge of the molecular pathways involved in the appearance and progression of medulloblastomas will allow us to offer a prognosis at the time of diagnosis and more specific treatments through the development of the targeted therapy.


Asunto(s)
Neoplasias Encefálicas , Neoplasias Cerebelosas , Meduloblastoma , Humanos , Niño , Meduloblastoma/genética , Meduloblastoma/terapia , Meduloblastoma/metabolismo , Marcadores Genéticos , Neoplasias Cerebelosas/genética , Neoplasias Cerebelosas/terapia , Neoplasias Cerebelosas/metabolismo , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/terapia , Terapia Combinada
8.
Taiwan J Obstet Gynecol ; 62(3): 412-416, 2023 May.
Artículo en Inglés | MEDLINE | ID: mdl-37188445

RESUMEN

OBJECTIVE: To assess the incidence of threatened preterm labor and preterm labor admissions and treatment of women with singleton gestations and no prior preterm birth before and after implementation of the universal mid-trimester transvaginal ultrasound cervical length screening. MATERIALS AND METHODS: A retrospective cohort study included of singleton gestations without a history of preterm birth presenting with threatened preterm labor between 24 0/7 and 36 6/7 gestational week in two study periods: before and after the implementation of the universal cervical length screening. Women with cervical length <25 mm were considered being at high risk for preterm birth and were prescribed a treatment with vaginal progesterone daily. The primary outcome was the incidence of threatened preterm labor. Secondary outcomes were the incidence of preterm labor. RESULTS: We have found a significant increase in the incidence of threatened preterm labor from 6.42% (410/6378) in 2011 to 11.61% (483/4158) in 2018 (p < 0.0001). Gestational age at triage consult was lower in than in 2011, although the rate of admission for threatened preterm labor was similar in both periods. There was a significant decrease in the incidence of preterm delivery <37 weeks from 25.60% in 2011 to 15.94% in 2018 (p < 0.0004). Although there was a reduction in preterm delivery ≤34 weeks, this reduction was not significant. CONCLUSION: The universal mid-trimester cervical length screening in asymptomatic women is not associated with a reduction in the frequency of threatened preterm labor or the admission rate for preterm labor, but reduces the rate of preterm births.


Asunto(s)
Trabajo de Parto Prematuro , Nacimiento Prematuro , Embarazo , Femenino , Recién Nacido , Humanos , Nacimiento Prematuro/epidemiología , Nacimiento Prematuro/prevención & control , Estudios Retrospectivos , Trabajo de Parto Prematuro/epidemiología , Trabajo de Parto Prematuro/prevención & control , Segundo Trimestre del Embarazo , Cuello del Útero/diagnóstico por imagen , Medición de Longitud Cervical
9.
Phys Chem Chem Phys ; 14(9): 3234-47, 2012 Mar 07.
Artículo en Inglés | MEDLINE | ID: mdl-22294155

RESUMEN

The dissociation of H(2) on Ti-covered Al surfaces is relevant to the rehydrogenation and dehydrogenation of the NaAlH(4) hydrogen storage material. The energetically most stable structure for a 1/2 monolayer of Ti deposited on the Al(100) surface has the Ti atoms in the second layer with a c(2 × 2) structure, as has been confirmed by both low-energy electron diffraction and low-energy ion scattering experiments and density functional theory studies. In this work, we investigate the dynamics of H(2) dissociation on a slab model of this Ti/Al(100) surface. Two six-dimensional potential energy surfaces (PESs) have been built for this H(2) + Ti/Al(100) system, based on the density functional theory PW91 and RPBE exchange-correlation functionals. In the PW91 (RPBE) PES, the lowest H(2) dissociation barrier is found to be 0.65 (0.84) eV, with the minimum energy path occurring for H(2) dissociating above the bridge to top sites. Using both PESs, H(2) dissociation probabilities are calculated using the classical trajectory (CT), the quasi-classical trajectory (QCT), and the time-dependent wave-packet methods. We find that the QCT H(2) dissociation probabilities are in good agreement with the quantum dynamics results in the collision energy range studied up to 1.0 eV. We have also performed molecular beam simulations and present predictions for molecular beam experiments. Our molecular beam simulations show that H(2) dissociation on the 1/2 ML Ti/Al(100) surface is an activated process, and the reaction probability is found to be 6.9% for the PW91 functional and 1.8% for the RPBE at a nozzle temperature of 1700 K. Finally, we have also calculated H(2) dissociation rate constants by applying transition state theory and the QCT method, which could be relevant to modeling Ti-catalyzed rehydrogenation and dehydrogenation of NaAlH(4).

10.
J Clin Rheumatol ; 18(7): 327-35, 2012 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-23047532

RESUMEN

BACKGROUND: Treatment of rheumatoid arthritis (RA) has evolved dramatically in the last decade. However, little is known about the way rheumatologists in Latin America treat their patients in clinical practice, outside the scope of clinical trials. OBJECTIVE: The objective of this study was to describe treatment patterns at disease onset in early RA with data from a large, multicenter, multinational inception cohort of Latin American patients. METHODS: Consecutive patients with early RA (<1 year of disease duration as diagnosed by a rheumatologist) from 46 centers in 14 Latin American countries were enrolled in the study. Clinical data, laboratory assessments, and a detailed registry on type of prescriptions were collected at baseline and at 3, 6, 12, 18, and 24 months of follow-up. Hands and feet x-rays were obtained at baseline and at 12 and 24 months. All data were captured in Arthros 6.1 database. Continuous variables were expressed as means and SDs, and categorical variables were expressed as percentages and 95% confidence intervals (95% CIs). Only therapeutic data at baseline are presented, corresponding to the period between disease onset and second visit (3 months). RESULTS: A total of 1093 patients were included. Eighty-five percent were female, and 76% had a positive rheumatoid factor. Mean age at diagnosis was 46.5 (SD, 14.2) years, and mean disease duration at the first visit was 5.8 (SD, 3.8) months. Between baseline and second visit (3 months), 75% of patients (95% CI, 72%-78%) received disease-modifying antirheumatic drugs. Methotrexate (MTX) alone or in combination was the most frequently used (60.5%), followed by antimalarials (chloroquine or hydroxychloroquine, 32.1%), sulfasalazine (7.1%), and leflunomide (LEF, 4%). In 474 patients (43%), initiation of disease-modifying antirheumatic drugs was within the first month after the first visit. In addition, 290 patients (26%; 95% CI, 23%-29%) received combination therapy as initial treatment. The most frequently used combinations were MTX + chloroquine (45%), MTX + hydroxychloroquine (25%), and MTX + sulfasalazine (16%). Eleven patients (1%; 95% CI, 0.5%-1.8%) received biologics. Sixty-four percent (95% CI, 60%-66%) received corticosteroids. Of those, 80% (95% CI, 77%-84%) received 10 mg of oral prednisone or less. CONCLUSIONS: In this cohort of Latin American patients with early RA, most patients received MTX very early in their disease course. Combination therapy was used approximately in 1 of every 4 patients as initial therapy. Biologics were rarely used at this early stage, and low-dose prednisone was commonly used.


Asunto(s)
Antirreumáticos/uso terapéutico , Artritis Reumatoide/tratamiento farmacológico , Artritis Reumatoide/etnología , Manejo de la Enfermedad , Adulto , Antimaláricos/uso terapéutico , Artritis Reumatoide/epidemiología , Estudios de Cohortes , Quimioterapia Combinada , Femenino , Estudios de Seguimiento , Humanos , Isoxazoles/uso terapéutico , América Latina/epidemiología , Leflunamida , Masculino , Metotrexato/uso terapéutico , Persona de Mediana Edad , Sistema de Registros , Sulfasalazina/uso terapéutico , Resultado del Tratamiento
11.
Phys Chem Chem Phys ; 13(42): 19067-76, 2011 Nov 14.
Artículo en Inglés | MEDLINE | ID: mdl-21674116

RESUMEN

We report a quantum dynamics study of O + OH (v = 1, j = 0) collisions on its ground electronic state, employing two different potential energy surfaces: the DIMKP surface by Kendrick and Pack, and the XXZLG surface by Xu et al. A time-independent quantum mechanical method based on hyperspherical coordinates has been adopted for the dynamics calculations. Energy-dependent probabilities and rate coefficients are computed for the elastic, inelastic, and reactive channels over the collision energy range E(coll) = 10(-10)-0.35 eV, for J = 0 total angular momentum. Initial state-selected reaction rate coefficients are also calculated from the J = 0 reaction probabilities by applying a J-shifting approximation, for temperatures in the range T = 10(-6)-700 K. Our results show that the dynamics of the collisional process and its outcome are strongly influenced by long-range forces, and chemical reactivity is found to be sensitive to the choice of the potential energy surface. For O + OH (v = 1, j = 0) collisions at low temperatures, vibrational relaxation of OH competes with reactive scattering. Since long-range interactions can facilitate vibrational relaxation processes, we find that the DIMKP potential (which explicitly includes van der Waals dispersion terms) favours vibrational relaxation over chemical reaction at low temperatures. On the DIMKP potential in the ultracold regime, the reaction rate coefficient for O + OH (v = 1, j = 0) is found to be a factor of thirteen lower than that for O + OH (v = 0, j = 0). This significantly high reactivity of OH (v = 0, j = 0), compared to that of OH (v = 1, j = 0), is attributed to enhancement caused by the presence of a HO(2) quasibound state (scattering resonance) with energy near the O + OH (v = 0, j = 0) dissociation threshold. In contrast, the XXZLG potential does not contain explicit van der Waals terms, being just an extrapolation by a nearly constant function at large O-OH distances. Therefore, long-range potential couplings are absent in calculations using the XXZLG surface, which does not induce vibrational relaxation as efficiently as the DIMKP potential. The XXZLG potential leads to a slightly higher reactivity (a factor of 1.4 higher) for O + OH (v = 1, j = 0) compared to that for O + OH (v = 0, j = 0) at ultracold temperatures. Overall, both potential surfaces yield comparable values of reaction rate coefficients at low temperatures for the O + OH (v = 1, j = 0) reaction.

12.
Phys Chem Chem Phys ; 13(38): 16955-72, 2011 Oct 14.
Artículo en Inglés | MEDLINE | ID: mdl-21887432

RESUMEN

The widespread adoption of hydrogen as an energy carrier could bring significant benefits, but only if a number of currently intractable problems can be overcome. Not the least of these is the problem of storage, particularly when aimed at use onboard light-vehicles. The aim of this overview is to look in depth at a number of areas linked by the recently concluded HYDROGEN research network, representing an intentionally multi-faceted selection with the goal of advancing the field on a number of fronts simultaneously. For the general reader we provide a concise outline of the main approaches to storing hydrogen before moving on to detailed reviews of recent research in the solid chemical storage of hydrogen, and so provide an entry point for the interested reader on these diverse topics. The subjects covered include: the mechanisms of Ti catalysis in alanates; the kinetics of the borohydrides and the resulting limitations; novel transition metal catalysts for use with complex hydrides; less common borohydrides; protic-hydridic stores; metal ammines and novel approaches to nano-confined metal hydrides.

13.
J Chem Phys ; 134(11): 114708, 2011 Mar 21.
Artículo en Inglés | MEDLINE | ID: mdl-21428657

RESUMEN

Based on a slab model of H(2) dissociation on a c(2 × 2) structure with Ti atoms in the first and third layers of Al(100), a six-dimensional (6D) potential energy surface (PES) has been built. In this PES, a molecular adsorption well with a depth of 0.45 eV is present in front of a barrier of height 0.13 eV. Using this PES, H(2) dissociation probabilities are calculated by the classical trajectory (CT), the quasiclassical trajectory (QCT), and the time-dependent wave-packet (TDWP) method. The QCT study shows that trajectories can be trapped by the molecular adsorption well. Higher incident energy can lead to direct H(2) dissociation. Vibrational pre-excitation is the most efficient way to promote direct dissociation without trapping. We find that both rotational and vibrational excitation have efficacies close to 1.0 in the entire range of incident energies investigated, which supports the randomization in the initial conditions making the reaction rate solely dependent on the total (internal and translational) energy. The H(2) dissociation probabilities from quantum dynamics are in reasonable agreement with the QCT results in the energy range 50-200 meV, except for some fluctuations. However, the TDWP results considerably exceed the QCT results in the energy range 200-850 meV. The CT reaction probabilities are too low compared with the quantum dynamical results.

14.
J Clin Rheumatol ; 17(1): 18-22, 2011 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-21169854

RESUMEN

BACKGROUND: Ultrasound has demonstrated to be a highly sensitive tool in the evaluation of entheses in spondyloarthropathy (SpA) patients and improves the ability of clinical examination to detect enthesopathy. OBJECTIVES: The objectives of the study were to determine the prevalence of subclinical enthesopathy in SpA patients and to evaluate the reliability of ultrasound in the detection of abnormal findings indicative of enthesopathy. METHODS: Six hundred lower-limb entheses were assessed in 60 SpA patients without known history of entheseal involvement. Sixty rheumatoid arthritis patients and 30 control subjects were included as control groups. Clinical examination and ultrasound were consecutively performed at each of the entheses to detect signs indicative of enthesopathy. Images from 20 SpA patients were stored and afterward evaluated to determine the reliability of abnormal ultrasound findings. RESULTS: Ultrasound detected a high prevalence of enthesopathy in SpA patients with respect to both rheumatoid arthritis patients and control subjects (P < 0.001 for both comparisons). In SpA patients, clinical examination detected enthesopathy in 56 (9.3%) of 600 entheses. In the remainder 544 clinically asymptomatic entheses (90.7%) (not painful and not swollen), ultrasound detected in 331 (60.8%) at least 1 ultrasound sign of enthesopathy. The intrareader and interreader agreement for all ultrasound abnormal findings was good to excellent. CONCLUSION: The present study demonstrates a higher sensitivity of ultrasound with respect to physical examination in the detection of signs indicative of enthesopathy in SpA patients with an adequate interreader and intrareader reliability. Further study is needed about the prognostic value of the ultrasound findings for predicting clinical onset of entheseal involvement.


Asunto(s)
Enfermedades Reumáticas/diagnóstico por imagen , Enfermedades Reumáticas/epidemiología , Espondiloartropatías/diagnóstico por imagen , Espondiloartropatías/epidemiología , Adulto , Comorbilidad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Prevalencia , Sensibilidad y Especificidad , Ultrasonografía , Adulto Joven
15.
Phys Chem Chem Phys ; 12(6): 1331-40, 2010 Feb 14.
Artículo en Inglés | MEDLINE | ID: mdl-20119611

RESUMEN

We have studied hydrogen dissociation on a CO-precovered Ru(0001) surface, by means of six-dimensional (6D) quasi-classical and quantum dynamics. The 6D potential energy surface has been built by applying a modified Shepard interpolation method to a set of density functional theory (DFT) data, for a coverage of 1/3 monolayer CO. We compared our theoretical results to the experimental ones obtained by Ueta et al. [ChemPhysChem, 2008, 9, 2372]. In order to do so, we have simulated the supersonic molecular beam used in the experiments by taking into account the energy distribution and rovibrational states population in the molecular beam. We find that both the energy and rovibrational states distributions of the molecular beam influence the reactivity, with the largest effect being caused by the energy distribution. However, a significant discrepancy between theory and experiment persists. We argue that this discrepancy could be due to the RPBE functional used in the DFT calculations and/or the neglect of CO-motion in the calculations.

16.
J Clin Rheumatol ; 16(3): 113-8, 2010 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-20375820

RESUMEN

OBJECTIVE: To develop guidelines for Musculoskeletal Ultrasound (MSKUS) training for rheumatologists in the Americas. METHODS: A total of 25 Rheumatologists from 19 countries of the American Continent participated in a consensus-based interactive process (Delphi method) using 2 consecutive electronic questionnaires. The first questionnaire included the following: the relevance of organizing courses to teach MSKUS to Rheumatologists, the determination of the most effective educational course models, the trainee levels, the educational objectives, the requirements for passing the course(s), the course venues, the number of course participants per instructor, and the percentage of time spent in hands-on sessions. The second questionnaire consisted of questions that did not achieve consensus (>65%) in the first questionnaire, topics, and pathologies to be covered at each course MSKUS level. RESULTS: General consensus was obtained for MSKUS courses to be divided into 3 educational levels: basic, intermediate, and advanced. These courses should be taught using a theoretical-didactic and hands-on model. In addition, the group established the minimum requirements for attending and passing each MSKUS course level, the ideal number of course participants per instructor (4 participants/instructor), and the specific topics and musculoskeletal pathologies to be covered. In the same manner, the group concluded that 60% to 70% of course time should be focused on hands-on sessions. CONCLUSION: A multinational group of MSKUS sonographers using a consensus-based questionnaire (Delphi method) established the first recommendations and guidelines for MSKUS course training in the Americas. Pan-American League of Associations for Rheumatology urges that these guidelines and recommendations be adopted in the future by both national and regional institutions in the American continent involved in the training of Rheumatologists for the performance of MSKUS.


Asunto(s)
Educación Médica Continua/normas , Reumatología/educación , Ultrasonografía/normas , Américas , Técnica Delphi , Humanos , Enfermedades Musculoesqueléticas/diagnóstico por imagen
17.
J Chem Phys ; 128(21): 211101, 2008 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-18537408

RESUMEN

We report a quantum dynamics study of H + H(2)(+) (v(0) = 0, j(0) = 0) scattering on its lowest triplet state, for J = 0 total angular momentum and total energies up to 1.85 eV. This provides a benchmark example of indirect resonance-mediated reaction in presence of a conical intersection (CI). Visualization of time-dependent wave packets shows significant "looping" around the CI, which is facilitated by long-lived H(3)(+) scattering resonances, predominant at low energies. State-to-state inelastic transition probabilities exhibit a highly oscillatory structure and pronounced geometric phase effects, which, in contrast to direct reactions, are more strongly marked at lower energies.

18.
Clin Rheumatol ; 27(3): 399-402, 2008 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-17938989

RESUMEN

Chronic intestinal pseudo-obstruction (CIPO), a recently recognized manifestation of systemic lupus erythematosus (SLE) with only 23 cases reported in the English literature, may appear as a complication or as the initial presentation of SLE and usually occurs during the setting of an active lupus. The pathogenic mechanism in SLE is unknown. We describe four additional cases with clinical, radiological, and manometric features of CIPO. As SLE-related CIPO usually responds to treatment with high doses of corticosteroids and/or immunosuppressive and prokinetic agents, a high level of awareness of this complication is needed to avoid unnecessary surgical intervention.


Asunto(s)
Antiinflamatorios/efectos adversos , Fármacos Gastrointestinales/uso terapéutico , Seudoobstrucción Intestinal/complicaciones , Lupus Eritematoso Sistémico/complicaciones , Adulto , Femenino , Humanos , Seudoobstrucción Intestinal/tratamiento farmacológico , Seudoobstrucción Intestinal/inmunología , Lupus Eritematoso Sistémico/tratamiento farmacológico , Persona de Mediana Edad
19.
Math Biosci ; 208(2): 495-520, 2007 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-17306839

RESUMEN

We carry out a simulation of the female population of the USA using the non-autonomous Lotka-McKendrick model with finite maximum age and recent demographic data. The most important contributions in our study are the identification of the mortality rate (including the maximum age) and the design and analysis of a numerical method that works efficiently with unbounded mortality rates. We also consider the effect in the population projections produced by different ways to choose the vital rates and we present a sensitivity analysis with respect to the mortality. Finally, we exemplify the limitations the data impose on the quality of the projections of this model through a 10-year simulation for the USA from 1990 to 2000 and we project the female population of the USA in 2010 using this model.


Asunto(s)
Demografía , Modelos Biológicos , Mortalidad , Adolescente , Adulto , Distribución por Edad , Anciano , Anciano de 80 o más Años , Niño , Preescolar , Femenino , Fertilidad , Humanos , Lactante , Recién Nacido , Matemática , Persona de Mediana Edad , Modelos Estadísticos
20.
J Rheumatol ; 44(12): 1804-1812, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29093158

RESUMEN

OBJECTIVE: To define whether Amerindian genetic ancestry correlates with clinical and therapeutic variables in admixed individuals with rheumatoid arthritis (RA) from Latin America. METHODS: Patients with RA (n = 1347) and healthy controls (n = 1012) from Argentina, Mexico, Chile, and Peru were included. Samples were genotyped for the Immunochip v1 using the Illumina platform. Clinical data were obtained through interviews or the clinical history. RESULTS: Percentage of Amerindian ancestry was comparable between cases and controls. Morning stiffness (p < 0.0001, OR 0.05), rheumatoid factor (RF; p < 0.0001, OR 0.22), radiographic changes (p < 0.0001, OR 0.05), and higher number of criteria were associated with lower Amerindian ancestry after Bonferroni correction. Higher Amerindian ancestry correlated only with weight loss (pBonferroni < 0.0001, OR 2.85). Increased Amerindian ancestry correlated with higher doses of azathioprine (p < 0.0001, OR 163.6) and sulfasalazine (p < 0.0001, OR 48.6), and inversely with methotrexate (p = 0.001, OR 0.35), leflunomide (p = 0.001, OR 0.16), and nonsteroidal antiinflammatory drugs (pBonferroni = 0.001, OR 0.37). Only the presence of RF and weight loss were modified after confounders adjustment. CONCLUSION: Amerindian ancestry protects against most major clinical criteria of RA, but regarding the association of RF with increased European ancestry, age, sex, and smoking are modifiers. Ancestry also correlates with the therapeutic profiles.


Asunto(s)
Antiinflamatorios no Esteroideos/uso terapéutico , Antirreumáticos/uso terapéutico , Artritis Reumatoide/genética , Genotipo , Factor Reumatoide/genética , Adulto , Factores de Edad , Anciano , Alelos , Argentina , Artritis Reumatoide/diagnóstico por imagen , Artritis Reumatoide/tratamiento farmacológico , Chile , Femenino , Humanos , Indígenas Norteamericanos , Indígenas Sudamericanos , Isoxazoles/uso terapéutico , Leflunamida , Masculino , Metotrexato/uso terapéutico , México , Persona de Mediana Edad , Perú , Radiografía , Factores Sexuales , Sulfasalazina/uso terapéutico
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