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1.
Cir Cir ; 89(S2): 38-40, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34932537

RESUMO

Paraclinoid aneurysms take importance due to the technical difficulty due to anatomical relationships, which is why different approaches have been sought for their proper management. This is a female patient with a finding of a paraclinoid aneurysm and treatment using an endonasal approach with adequate angiographic support. Knowledge of the anatomy and surgical skill are required for the management of these lesions, assisted by angiographic controls for successful treatment. The endoscopic endonasal approach is adequate if the anatomy allows it and the basic hospital infrastructure is available to obtain high success rates.


Los aneurismas paraclinoideos cobran importancia debido a la dificultad técnica por sus relaciones anatómicas, por lo que se han buscado diferentes abordajes para su adecuado manejo. Se presenta el caso de una paciente con un aneurisma paraclinoideo y tratamiento mediante abordaje endonasal con apoyo angiográfico adecuado. Se requieren conocimientos de la anatomía y habilidad quirúrgica para el manejo de estas lesiones, así como asistencia de controles angiográficos para el éxito del tratamiento. El abordaje endonasal endoscópico es adecuado en caso de que la anatomía lo permita y se tenga la infraestructura hospitalaria básica para obtener un alto índice de éxitos.


Assuntos
Aneurisma Intracraniano , Angiografia , Feminino , Humanos , Aneurisma Intracraniano/diagnóstico por imagem , Aneurisma Intracraniano/cirurgia , México , Microcirurgia , Procedimentos Neurocirúrgicos
2.
JCO Glob Oncol ; 7: 1151-1166, 2021 07.
Artigo em Inglês | MEDLINE | ID: mdl-34270330

RESUMO

PURPOSE: Adult T-cell leukemia/lymphoma (ATLL) is an aggressive disease caused by the human T-cell leukemia virus type 1. Real-world data of ATLL in Latin America are lacking. PATIENTS AND METHODS: We analyzed patients with ATLL (acute, lymphomatous, chronic, and smoldering) encountered in 11 Latin American countries between 1995 and 2019. Treatment response was assessed according to the 2009 consensus report. Survival curves were estimated using the Kaplan-Meier method and log-rank test. RESULTS: We identified 253 patients; 226 (lymphomatous: n = 122, acute: n = 73, chronic: n = 26, and smoldering: n = 5) had sufficient data for analysis (median age 57 years). Most patients with ATLL were from Peru (63%), Chile (17%), Argentina (8%), and Colombia (7%). Hypercalcemia was positively associated with acute type (57% v lymphomatous 27%, P = .014). The median survival times (months) were 4.3, 7.9, 21.1, and not reached for acute, lymphomatous, chronic, and smoldering forms, with 4-year survival rates of 8%, 22%, 40%, and 80%, respectively. First-line zidovudine (AZT)-interferon alfa (IFN) resulted in an overall response rate of 63% (complete response [CR] 24%) for acute. First-line chemotherapy yielded an overall response rate of 41% (CR 29%) for lymphomatous. CR rate was 42% for etoposide, cyclophosphamide, vincristine, doxorubicin, and prednisone versus 12% for cyclophosphamide, vincristine, doxorubicin, and prednisone-like regimen (P < .001). Progression-free survival at 1 year for acute type patients treated with AZT-IFN was 67%, whereas 2-year progression-free survival in lymphomatous type patients who achieved CR after chemotherapy was 77%. CONCLUSION: This study confirms Latin American ATLL presents at a younger age and has a high incidence of lymphomatous type, low incidence of indolent subtypes, and worse survival rates as compared with Japanese patients. In aggressive ATLL, chemotherapy remains the preferred choice for lymphomatous favoring etoposide-based regimen (etoposide, cyclophosphamide, vincristine, doxorubicin, and prednisone), whereas AZT-IFN remains a good first-line option for acute subtype.


Assuntos
Leucemia-Linfoma de Células T do Adulto , Linfoma , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Argentina , Chile , Colômbia , Humanos , América Latina/epidemiologia , Leucemia-Linfoma de Células T do Adulto/tratamento farmacológico , Leucemia-Linfoma de Células T do Adulto/epidemiologia , Pessoa de Meia-Idade , Peru/epidemiologia
3.
Clin Lymphoma Myeloma Leuk ; 20(10): 637-646, 2020 10.
Artigo em Inglês | MEDLINE | ID: mdl-32513598

RESUMO

INTRODUCTION: We aimed at investigating the prognostic role of the neutrophil-to-lymphocyte ratio (NLR) in 2 independent cohorts of Latin American patients with diffuse large B-cell lymphoma (DLBCL) treated with chemoimmunotherapy. PATIENTS AND METHODS: The learning cohort was composed of 274 patients and the validation cohort of 323 patients, for a total of 597 patients. An optimal NLR cutoff ≥ 4 was determined using receiver operating characteristic analysis. RESULTS: In multivariate models, NLR ≥ 4 was independently associated with lower odds for complete response to chemoimmunotherapy in the learning (odds ratio, 0.46; P = .006) and the validation cohort (odds ratio, 0.49; P = .01), and independently associated with worse survival in the learning (hazard ratio, 1.55; P = .04) and the validation cohort (hazard ratio, 1.80; P = .003). CONCLUSIONS: The adverse prognostic value of NLR ≥ 4 was independent of the International Prognostic Index and the National Comprehensive Cancer Network-International Prognostic Index score. Based on the results of this multi-institutional study, NLR ≥ 4 emerges as an adverse prognostic factor in Latin American patients with DLBCL treated with chemoimmunotherapy.


Assuntos
Linfócitos/metabolismo , Linfoma Difuso de Grandes Células B/sangue , Neutrófilos/metabolismo , Feminino , Humanos , Linfoma Difuso de Grandes Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Prognóstico , Análise de Sobrevida
4.
Exp Brain Res ; 238(3): 537-550, 2020 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-31974755

RESUMO

Electroencephalography (EEG) activity in the mu frequency band (8-13 Hz) is suppressed during both gesture performance and observation. However, it is not clear if or how particular characteristics within the kinematic execution of gestures map onto dynamic changes in mu activity. Mapping the time course of gesture kinematics onto that of mu activity could help understand which aspects of gestures capture attention and aid in the classification of communicative intent. In this work, we test whether the timing of inflection points within gesture kinematics predicts the occurrence of oscillatory mu activity during passive gesture observation. The timing for salient features of performed gestures in video stimuli was determined by isolating inflection points in the hands' motion trajectories. Participants passively viewed the gesture videos while continuous EEG data was collected. We used wavelet analysis to extract mu oscillations at 11 Hz and at central electrodes and occipital electrodes. We used linear regression to test for associations between the timing of inflection points in motion trajectories and mu oscillations that generalized across gesture stimuli. Separately, we also tested whether inflection point occurrences evoked mu/alpha responses that generalized across participants. Across all gestures and inflection points, and pooled across participants, peaks in 11 Hz EEG waveforms were detected 465 and 535 ms after inflection points at occipital and central electrodes, respectively. A regression model showed that inflection points in the motion trajectories strongly predicted subsequent mu oscillations ([Formula: see text]<0.01); effects were weaker and non-significant for low (17 Hz) and high (21 Hz) beta activity. When segmented by inflection point occurrence rather than stimulus onset and testing participants as a random effect, inflection points evoked mu and beta activity from 308 to 364 ms at central electrodes, and broad activity from 226 to 800 ms at occipital electrodes. The results suggest that inflection points in gesture trajectories elicit coordinated activity in the visual and motor cortices, with prominent activity in the mu/alpha frequency band and extending into the beta frequency band. The time course of activity indicates that visual processing drives subsequent activity in the motor cortex during gesture processing, with a lag of approximately 80 ms.


Assuntos
Atenção/fisiologia , Ondas Encefálicas/fisiologia , Fenômenos Eletrofisiológicos/fisiologia , Gestos , Adolescente , Adulto , Eletroencefalografia/métodos , Feminino , Humanos , Masculino , Neurônios-Espelho/fisiologia , Córtex Motor/fisiologia , Desempenho Psicomotor/fisiologia , Percepção Visual/fisiologia , Adulto Jovem
5.
Surgery ; 167(4): 724-731, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-31916990

RESUMO

BACKGROUND: The surgical workforce particularly in rural regions needs novel approaches to reinforce the skills and confidence of health practitioners. Although conventional telementoring systems have proven beneficial to address this gap, the benefits of platforms of augmented reality-based telementoring in the coaching and confidence of medical personnel are yet to be evaluated. METHODS: A total of 20 participants were guided by remote expert surgeons to perform leg fasciotomies on cadavers under one of two conditions: (1) telementoring (with our System for Telementoring with Augmented Reality) or (2) independently reviewing the procedure beforehand. Using the Individual Performance Score and the Weighted Individual Performance Score, two on-site, expert surgeons evaluated the participants. Postexperiment metrics included number of errors, procedure completion time, and self-reported confidence scores. A total of six objective measurements were obtained to describe the self-reported confidence scores and the overall quality of the coaching. Additional analyses were performed based on the participants' expertise level. RESULTS: Participants using the System for Telementoring with Augmented Reality received 10% greater Weighted Individual Performance Score (P = .03) and performed 67% fewer errors (P = .04). Moreover, participants with lower surgical expertise that used the System for Telementoring with Augmented Reality received 17% greater Individual Performance Score (P = .04), 32% greater Weighted Individual Performance Score (P < .01) and performed 92% fewer errors (P < .001). In addition, participants using the System for Telementoring with Augmented Reality reported 25% more confidence in all evaluated aspects (P < .03). On average, participants using the System for Telementoring with Augmented Reality received augmented reality guidance 19 times on average and received guidance for 47% of their total task completion time. CONCLUSION: Participants using the System for Telementoring with Augmented Reality performed leg fasciotomies with fewer errors and received better performance scores. In addition, participants using the System for Telementoring with Augmented Reality reported being more confident when performing fasciotomies under telementoring. Augmented Reality Head-Mounted Display-based telementoring successfully provided confidence and coaching to medical personnel.


Assuntos
Realidade Aumentada , Cirurgia Geral/educação , Tutoria/métodos , Telemedicina/métodos , Adulto , Feminino , Humanos , Masculino
6.
Am J Hematol ; 95(2): 151-155, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31709579

RESUMO

The T Cell Project was the largest prospective trial to explore the incidence, treatment patterns, and outcomes for T cell lymphomas. The rare subtypes of T cell lymphomas, including hepatosplenic T cell lymphoma (HSTCL), enteropathy associated T cell lymphoma (EATL), and peripheral gamma delta T cell lymphomas (PGDTCLs) are poorly represented in most studies and there is little data regarding treatment patterns. We report results from 115 patients with hepatosplenic (n = 31), enteropathy associated (n = 65), and PGDTCLs (n = 19). While anthracycline regimens were most commonly used as first line therapy, response rates ranged from 20%-40% and were suboptimal for all groups. Autologous stem cell transplantation was performed as a consolidation in first remission in a small number of patients (33% of HSTCL, 7% of EATL, and 12% of PGDTCL), and four patients with HSTCL underwent allogeneic stem cell transplantation in first remission. The progression free survival at 3 years ranged from 28%-40% for these rare subtypes, and the overall survival at 3 years was most favorable for PGDTCL (70%). These data highlight the need for novel treatment approaches for rare subtypes of T cell lymphomas and for their inclusion in clinical trials.


Assuntos
Linfoma de Células T Associado a Enteropatia , Transplante de Células-Tronco Hematopoéticas , Linfoma de Células T Periférico , Proteínas de Neoplasias/sangue , Receptores de Antígenos de Linfócitos T gama-delta/sangue , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Linfoma de Células T Associado a Enteropatia/sangue , Linfoma de Células T Associado a Enteropatia/mortalidade , Linfoma de Células T Associado a Enteropatia/terapia , Feminino , Humanos , Incidência , Linfoma de Células T Periférico/sangue , Linfoma de Células T Periférico/mortalidade , Linfoma de Células T Periférico/terapia , Masculino , Pessoa de Meia-Idade , Taxa de Sobrevida , Transplante Autólogo
7.
Simul Healthc ; 14(1): 59-66, 2019 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-30395078

RESUMO

INTRODUCTION: Surgical telementoring connects expert mentors with trainees performing urgent care in austere environments. However, such environments impose unreliable network quality, with significant latency and low bandwidth. We have developed an augmented reality telementoring system that includes future step visualization of the medical procedure. Pregenerated video instructions of the procedure are dynamically overlaid onto the trainee's view of the operating field when the network connection with a mentor is unreliable. METHODS: Our future step visualization uses a tablet suspended above the patient's body, through which the trainee views the operating field. Before trainee use, an expert records a "future library" of step-by-step video footage of the operation. Videos are displayed to the trainee as semitransparent graphical overlays. We conducted a study where participants completed a cricothyroidotomy under telementored guidance. Participants used one of two telementoring conditions: conventional telestrator or our system with future step visualization. During the operation, the connection between trainee and mentor was bandwidth throttled. Recorded metrics were idle time ratio, recall error, and task performance. RESULTS: Participants in the future step visualization condition had 48% smaller idle time ratio (14.5% vs. 27.9%, P < 0.001), 26% less recall error (119 vs. 161, P = 0.042), and 10% higher task performance scores (rater 1 = 90.83 vs. 81.88, P = 0.008; rater 2 = 88.54 vs. 79.17, P = 0.042) than participants in the telestrator condition. CONCLUSIONS: Future step visualization in surgical telementoring is an important fallback mechanism when trainee/mentor network connection is poor, and it is a key step towards semiautonomous and then completely mentor-free medical assistance systems.


Assuntos
Mentores , Procedimentos Cirúrgicos Operatórios/educação , Telemedicina/instrumentação , Interface Usuário-Computador , Competência Clínica , Computadores de Mão , Humanos , Fatores de Tempo
8.
Nanomaterials (Basel) ; 8(11)2018 Nov 17.
Artigo em Inglês | MEDLINE | ID: mdl-30453604

RESUMO

ß-Cyclodextrin (ßCD), the less water soluble of the cyclodextrins, has been used as a capping agent in the preparation of semiconductor nanocrystals or quantum dots (QDs). Nevertheless, no reports have been found in the use of the highly water-soluble polymer of this, prepared by the crosslinking of the ßCD units with epichlorohydrin in basic medium (ßCDP). This polymer, besides to overcome the low solubility of the ßCD, increases the inclusion constant of the guest; two parameters that deserve its use as capping agent, instead of the native cyclodextrin. In the present manuscript, we afforded the in-situ aqueous preparation of cadmium telluride (CdTe) QDs capped with ßCDP. The polymer influence on the photoluminescent properties of the nanocrystals was analyzed. The ßCDP controls the nanocrystals growth during the Oswald ripening stage. Consequently, the CdTe capped ßCDP QDs showed lower Stokes-shift values, higher photoluminescent efficiency, and narrower size distribution than for nanocrystals obtained in the absence of polymer. Transmission electron microscopy (TEM) micrographs and energy dispersive X-ray spectroscopy (EDS) analysis revealed the composition and crystallinity of the CdTe QDs. This ßCDP capped CdTe QDs is a potential scaffold for the supramolecular modification of QDs surface.

9.
Br J Haematol ; 181(6): 760-769, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29672827

RESUMO

Different models to investigate the prognosis of peripheral T cell lymphoma not otherwise specified (PTCL-NOS) have been developed by means of retrospective analyses. Here we report on a new model designed on data from the prospective T Cell Project. Twelve covariates collected by the T Cell Project were analysed and a new model (T cell score), based on four covariates (serum albumin, performance status, stage and absolute neutrophil count) that maintained their prognostic value in multiple Cox proportional hazards regression analysis was proposed. Among patients registered in the T Cell Project, 311 PTCL-NOS were retained for study. At a median follow-up of 46 months, the median overall survival (OS) and progression-free survival (PFS) was 20 and 10 months, respectively. Three groups were identified at low risk (LR, 48 patients, 15%, score 0), intermediate risk (IR, 189 patients, 61%, score 1-2), and high risk (HiR, 74 patients, 24%, score 3-4), having a 3-year OS of 76% [95% confidence interval 61-88], 43% [35-51], and 11% [4-21], respectively (P < 0·001). Comparing the performance of the T cell score on OS to that of each of the previously developed models, it emerged that the new score had the best discriminant power. The new T cell score, based on clinical variables, identifies a group with very unfavourable outcomes.


Assuntos
Linfoma de Células T Periférico/mortalidade , Modelos Biológicos , Adulto , Idoso , Idoso de 80 Anos ou mais , Intervalo Livre de Doença , Feminino , Seguimentos , Humanos , Linfoma de Células T Periférico/terapia , Masculino , Pessoa de Meia-Idade , Valor Preditivo dos Testes , Fatores de Risco , Taxa de Sobrevida
10.
Haematologica ; 103(7): 1191-1197, 2018 07.
Artigo em Inglês | MEDLINE | ID: mdl-29599200

RESUMO

This analysis explored factors influencing survival of patients with primary refractory and relapsed peripheral T-cell lymphomas enrolled in the prospective International T-cell Project. We analyzed data from 1020 patients with newly diagnosed disease, enrolled between September 2006 and December 2015. Out of 937 patients who received first-line treatment, 436 (47%) were identified as refractory and 197 (21%) as relapsed. Median time from the end of treatment to relapse was 8 months (range 2-73). Overall, 75 patients (8%) were consolidated with bone marrow transplantation, including 12 refractory and 22 relapsed patients. After a median follow up of 38 months (range 1-96 months) from documentation of refractory/relapsed disease, 440 patients had died. The median overall survival (OS) was 5.8 months; 3-year overall survival rates were 21% and 28% for refractory and relapsed patients, respectively (P<0.001). Patients receiving or not salvage bone marrow transplantation had a 3-year survival of 48% and 18%, respectively (P<0.001). In a univariate Cox regression analysis, refractory disease was associated with a higher risk of death (HR=1.43, P=0.001), whereas late relapse (>12 months, HR 0.57, P=0.001) and salvage therapy with transplantation (HR=0.36, P<0.001) were associated with a better OS. No difference was found in OS with respect to histology. This study accurately reflects outcomes for patients treated according to standards of care worldwide. Results confirm that peripheral T-cell lymphomas patients had dismal outcome after relapse or progression. Patients with chemotherapy sensitive disease who relapsed after more than 12 months might benefit from consolidation bone marrow transplantation.


Assuntos
Linfoma de Células T Periférico/mortalidade , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Terapia Combinada , Resistencia a Medicamentos Antineoplásicos , Feminino , Pesquisas sobre Atenção à Saúde , Humanos , Linfoma de Células T Periférico/diagnóstico , Linfoma de Células T Periférico/epidemiologia , Linfoma de Células T Periférico/terapia , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Estudos Prospectivos , Recidiva , Resultado do Tratamento , Adulto Jovem
11.
Int J Radiat Oncol Biol Phys ; 97(1): 42-49, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-27839910

RESUMO

PURPOSE: To assess the predictive value of 18F-fluorodeoxyglucose positron emission tomography/computed tomography (PET/CT) for disease recurrence after immunochemotherapy (R-CHT) and mediastinal irradiation (RT), using the recently published criteria of the Lugano classification to predict outcomes for patients with primary mediastinal large B-cell lymphoma. METHODS AND MATERIALS: Among 125 patients prospectively enrolled in the IELSG-26 study, 88 were eligible for central review of PET/CT scans after completion of RT. Responses were evaluated using the 5-point Deauville scale at the end of induction R-CHT and after consolidation RT. According to the Lugano classification, a complete metabolic response (CMR) was defined by a Deauville score (DS) ≤3. RESULTS: The CMR (DS1, -2, or -3) rate increased from 74% (65 patients) after R-CHT to 89% (78 patients) after consolidation RT. Among the 10 patients (11%) with persistently positive scans, the residual uptake after RT was slightly higher than the liver uptake in 6 patients (DS4; 7%) and markedly higher in 4 patients (DS5; 4%): these patients had a significantly poorer 5-year progression-free survival and overall survival. At a median follow-up of 60 months (range, 35-107 months), no patients with a CMR after RT have relapsed. Among the 10 patients who did not reach a CMR, 3 of the 4 patients (positive predictive value, 75%) with DS5 after RT had subsequent disease progression (within the RT volume in all cases) and died. All patients with DS4 had good outcomes without recurrence. CONCLUSIONS: All the patients obtaining a CMR defined as DS ≤3 remained progression-free at 5 years, confirming the excellent negative predictive value of the Lugano classification criteria in primary mediastinal large B-cell lymphoma patients. The few patients with DS4 also had an excellent outcome, suggesting that they do not necessarily require additional therapy, because the residual 18F-fluorodeoxyglucose uptake may not reflect persistent lymphoma.


Assuntos
Fluordesoxiglucose F18 , Imunoterapia , Linfoma de Células B/radioterapia , Neoplasias do Mediastino/radioterapia , Tomografia por Emissão de Pósitrons combinada à Tomografia Computadorizada , Compostos Radiofarmacêuticos , Adulto , Protocolos de Quimioterapia Combinada Antineoplásica/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Bleomicina/administração & dosagem , Ciclofosfamida/administração & dosagem , Progressão da Doença , Intervalo Livre de Doença , Doxorrubicina/administração & dosagem , Etoposídeo/administração & dosagem , Feminino , Fluordesoxiglucose F18/farmacocinética , Humanos , Leucovorina/administração & dosagem , Fígado/diagnóstico por imagem , Fígado/metabolismo , Linfoma de Células B/diagnóstico por imagem , Linfoma de Células B/tratamento farmacológico , Linfoma de Células B/metabolismo , Masculino , Neoplasias do Mediastino/diagnóstico por imagem , Neoplasias do Mediastino/tratamento farmacológico , Neoplasias do Mediastino/metabolismo , Metotrexato/administração & dosagem , Neoplasia Residual , Prednisona/administração & dosagem , Estudos Prospectivos , Compostos Radiofarmacêuticos/farmacocinética , Dosagem Radioterapêutica , Radioterapia Conformacional , Recidiva , Rituximab/uso terapêutico , Estatísticas não Paramétricas , Vincristina/administração & dosagem , Adulto Jovem
12.
Inorg Chem ; 54(23): 11200-8, 2015 Dec 07.
Artigo em Inglês | MEDLINE | ID: mdl-26574913

RESUMO

Maghemite-like materials containing Fe(3+) and Cr(3+) in comparable amounts have been prepared by solution-combustion synthesis. The conditions of synthesis and the magnetic properties are described. These materials are ferrimagnetic and are much more stable than pure iron maghemite since their maghemite-hematite transformation takes place at about ∼ 700 °C instead of ∼ 300 °C, as usually reported. These materials were studied by synchrotron radiation X-ray diffraction (XRD) and by X-ray absorption fine structure (XAFS) of the K-absorption edge of two elements. High-resolution XRD patterns were processed by means of the Rietveld method. Thus, maghemites were studied by XAFS in both Fe and Cr K-edges to clarify the short-range structure of the investigated systems. Pre-edge decomposition and theoretical modeling of X-ray absorption near edge structure transitions were performed. The extended X-ray absorption fine structure (EXAFS) spectra were fitted considering the facts that the central atom of Fe is able to occupy octahedral and tetrahedral sites, each with a weight adjustment, while Cr occupies only octahedral sites. Interatomic distances were determined for x = 1, by fitting simultaneously both Fe and Cr K-edges average EXAFS spectra. The results showed that the cation vacancies tend to follow a regular pattern within the structure of the iron-chromium maghemite (FeCrO3).

13.
Materials (Basel) ; 9(1)2015 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-28787814

RESUMO

Currently, an intensive search for high-performance lead-free ferroelectric materials is taking place. ABO3 perovskites (A = Ba, Bi, Ca, K and Na; B = Fe, Nb, Ti, and Zr) appear as promising candidates. Understanding the structure-function relationship is mandatory, and, in this field, the roles of long- and short-range crystal orders and interactions are decisive. In this review, recent advances in the global and local characterization of ferroelectric materials by synchrotron light diffraction, scattering and absorption are analyzed. Single- and poly-crystal synchrotron diffraction studies allow high-resolution investigations regarding the long-range average position of ions and subtle global symmetry break-downs. Ferroelectric materials, under the action of electric fields, undergo crystal symmetry, crystallite/domain orientation distribution and strain condition transformations. Methodological aspects of monitoring these processes are discussed. Two-dimensional diffraction clarify larger scale ordering: polycrystal texture is measured from the intensities distribution along the Debye rings. Local order is investigated by diffuse scattering (DS) and X-ray absorption fine structure (XAFS) experiments. DS provides information about thermal, chemical and displacive low-dimensional disorders. XAFS investigation of ferroelectrics reveals local B-cation off-centering and oxidation state. This technique has the advantage of being element-selective. Representative reports of the mentioned studies are described.

14.
Int J Environ Res Public Health ; 11(7): 6612-38, 2014 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-24968208

RESUMO

Concentrations of As, Cu, Fe, Hg, Pb and Zn and activity concentrations from 234,238U and 210Po in water, fillet, liver and gills were determined in three stocked fish species from the Luis L. Leon reservoir, located in Northern Mexico. The considered species were Lepomis cyanellus, Cyprinus carpio and Ictalurus furcatus. 238U and 234U activity concentration (AC) in fillet samples showed values of 0.007-0.014 and 0.01-0.02 Bq∙kg-1 wet weight (ww), respectively. Liver samples for L. cyanellus, C. carpio and I. furcatus present 210Po AC of 1.16-3.26, 0.70-1.13 and 0.93-1.37 Bq∙kg-1 ww. Arsenic, mercury and lead concentration intervals in fillet samples were 0.13-0.39, 0.005-0.126 and 0.009-0.08 mg∙kg-1 ww, respectively, while in gill samples they were 0.11-0.43, 0.002-0.039 and 0.02-0.26 mg∙kg-1 ww. The elemental Bioaccumulation Factor (BAF) for fish tissues with respect to their concentrations in water was determined. L. cyanellus showed the highest BAF values for As and total U, being BAFAs = 37 and 40 L∙kg-1 in fillet and gills, respectively, and BAFU total = 1.5 L∙kg-1 in fillet. I. furcatus showed the highest BAF values for Hg and Pb, being BAFHg = 40 and 13 L∙kg-1 in fillet and gills, and BAFPb = 6.5 and 22 L∙kg-1 in fillet and gills, respectively. Some metal(loid) concentrations are slightly higher than European regulations for fish fillets. The difference in concentrations of metal(loid)s in fillet among the studied species is probably due to their differences in diet and habitat.


Assuntos
Peixes , Contaminação de Alimentos , Metaloides/toxicidade , Metais Pesados/toxicidade , Poluentes Químicos da Água/toxicidade , Poluentes Radioativos da Água/toxicidade , Adulto , Animais , Monitoramento Ambiental , Peixes/metabolismo , Brânquias/química , Brânquias/metabolismo , Humanos , Fígado/química , Fígado/metabolismo , Metaloides/análise , Metaloides/metabolismo , Metais Pesados/análise , Metais Pesados/metabolismo , México , Medição de Risco , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/metabolismo , Poluentes Radioativos da Água/análise , Poluentes Radioativos da Água/metabolismo , Abastecimento de Água
15.
Leuk Lymphoma ; 54(1): 62-8, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22784364

RESUMO

Consolidation radiotherapy (cRT) in patients with stage I/II diffuse large B-cell lymphoma of the Waldeyer's ring (WR-DLBCL) in complete remission (CR) after induction chemotherapy (CHT) is often associated with relevant acute and chronic toxicity, and its impact on survival remains to be defined. A total of 184 patients in CR after anthracycline-based chemotherapy were retrospectively analyzed: 62 underwent CHT alone (CHT group), while 122 (66%) patients were referred to cRT (CHT + RT group). After a median follow-up of 54 months, 36 patients (20%) experienced relapse: 19% in the CHT group and 20% in the CHT + RT group. At the time of analysis 47 (76%) CHT patients and 97 (80%) CHT + RT patients were alive. Five-year overall survival (OS), disease-free survival (DFS) and lymphoma-specific survival (LSS) were 80%, 74% and 86%, respectively. Five-year OS was significantly prolonged in the CHT + RT group, while DFS and LSS were similar between groups. This discrepancy was attributed to a high percentage of deaths due to unrelated causes in CHT patients. cRT does not prolong LSS in patients with early-stage WR-DLBCL in CR after anthracycline-containing chemotherapy. An international confirmatory trial is warranted.


Assuntos
Linfoma Difuso de Grandes Células B/patologia , Linfoma Difuso de Grandes Células B/radioterapia , Adolescente , Adulto , Idoso , Idoso de 80 Anos ou mais , Antraciclinas/administração & dosagem , Antineoplásicos/administração & dosagem , Protocolos de Quimioterapia Combinada Antineoplásica/uso terapêutico , Causas de Morte , Feminino , Humanos , Linfoma Difuso de Grandes Células B/tratamento farmacológico , Linfoma Difuso de Grandes Células B/mortalidade , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Estadiamento de Neoplasias , Recidiva , Indução de Remissão , Estudos Retrospectivos , Resultado do Tratamento , Adulto Jovem
16.
Materials (Basel) ; 6(11): 4967-4984, 2013 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-28788370

RESUMO

A description of methods and computer programs for the prediction of "coupling properties" in axially-textured polycrystals is presented. Starting data are the single-crystal properties, texture and stereography. The validity and proper protocols for applying the Voigt, Reuss and Hill approximations to estimate coupling properties effective values is analyzed. Working algorithms for predicting mentioned averages are given. Bunge's symmetrized spherical harmonics expansion of orientation distribution functions, inverse pole figures and (single and polycrystals) physical properties is applied in all stages of the proposed methodology. The established mathematical route has been systematized in a working computer program. The discussion of piezoelectricity in a representative textured ferro-piezoelectric ceramic illustrates the application of the proposed methodology. Polycrystal coupling properties, predicted by the suggested route, are fairly close to experimentally measured ones.

17.
Salus ; 6(2): 23-31, ago. 2002. ilus, tab, graf
Artigo em Espanhol | LILACS | ID: lil-502556

RESUMO

La homocisteína ha sido asociada con enfermedad vascular prematura, pudiendo actuar sinérgicamente con otros factores de riesgo como los niveles elevados de colesterol y triglicéridos, así como deficiencia de vitaminas. El presente trabajo se planteó establecer el efecto de la administración de homocisteína por vía parenteral y del ácido fólico por vía oral en la formación de ateromas en conejos. Para ello se estudiaron 15 conejos de raza Nueva Zelanda provenientes del Bioterio de la Universidad de Carabobo divididos en tres grupos, los cuales fueron alimentados con el siguiente esquema: grupo 1: conejarina Protinal tipo A; Grupo 2: homocisteína por vía parenteral subcutánea durante 40 días; Grupo 3: homocisteína de la misma forma que el grupo 2 y ácido fólico por vía oral. Se realizaron determinaciones de los niveles séricos de colesterol, HDL-C, LDL-C, triglicéridos, ácido fólico y homocisteína antes y después del período experimental. Los conejos fueron sacrificados y se les extrajo el corazón y la aorta, con la finalidad de realizar cortes histológicos de los mismos. Los resultados obtenidos revelan que los niveles de homocisteína fueron más altos en el grupo 2 que en los obtenidos en el grupo 1, siendo esta diferencia significativa entre los dos grupos P(0.000), observándose en el grupo 2 los ateromas más graves de grado IV y V; en el grupo 3 se aprecia que los niveles de homocisteína no aumentan; los niveles de ácido fólico en este grupo fueron más altos comparados con los otros; en este grupo se observaron ateromas menos graves de grado I y III. Se evidenció una correlación baja positiva entre la variable homocisteína y el ácido fólico del grupo 3 (R= 0,292) y una correlación alta entre los lípidos en el grupo 2 y 3


Assuntos
Animais , Coelhos , Aterosclerose , Coelhos , Homocisteína/administração & dosagem , Lipídeos , Ácido Fólico/administração & dosagem , Ácido Fólico/efeitos adversos , Ciências da Saúde , Venezuela
18.
Rev. cuba. endocrinol ; 9(1): 9-15, ene.-abr. 1998.
Artigo em Espanhol | CUMED | ID: cum-14506

RESUMO

La función de los anticuerpos maternos en el desarrollo de la TSH elevada transitoria (tr-HTSH) en el recién nacido y/o el hipotiroidiosmo congénito (CH) ha sido sugerida por varios autores, pero aún es motivo de discusión. Con el propósito de conocer la presencia en las madres de anticuerpos antitiroideos convencionales y su realación con HTSH-tr y CH, se estudiaron 563 madres en el período posparto en 3 grupos: I. 235 madres de recién nacidos con TSH elevada(>25mU/L) en muestra de suero del cordón unbilical (screening). II. 48 madres de niños con hipotiroidismo congénito (una madre con antireosis). III (grupo control). 280 madres de niños con TSH normal en muestra de suero del cordón. La frecuencia de Mab fue de 4,8 porciento (11/228) en el grupo I, 6,2 porciento (3/48) en el grupo II y 5,5 porciento (15/274) en el grupo III, sin diferencias significativas entre los grupos. Resultados similares se encontró para los Tab: 2,2 porciento (5/227), 0 porciento (0/48) y 0,4 porciento (1/271) en los grupos I, II y III; y para los TPO: 4,5 porciento (10/223), 2,2 porciento (1/48) y 3,2 porciento (8/253). No se encontraron diferencias significativas en la frecuencia de bocio y los valores medios de TSH y T4 en los diferentes grupos. En conclusión, la presencia materna de los anticuerpos antitiroideos estudiados (Mab, Tab y TPO) no desempeñan una función importante en la génesis de tr-HTSH o CH en el recién nacido (AU)


Assuntos
Humanos , Feminino , Adulto , Adolescente , Recém-Nascido , Anticorpos/análise , Glândula Tireoide , Tireotropina/análise , Hipotireoidismo/congênito , Testes de Função Tireóidea , Tiroxina/análise , Programas Nacionais de Saúde
19.
Rev. cuba. endocrinol ; 9(1): 9-15, 1998. tab
Artigo em Espanhol | LILACS | ID: lil-271219

RESUMO

La función de los anticuerpos tiroideos maternos en el desarrollo de la TSH elevada transitoria (tr-HTSH) en el recién nacido y/o el hipotiroidismo congénito (CH) ha sido sugerido por varios autores, pero aún es motivo de discusión. Con el propósito de conocer la presencia en las madres de anticuerpos antitiroideos convencionales y su relación con HTSH-tr y CH, se estudiaron 563 madres en el período posparto en 3 grupos: I. 235 madres de recién nacidos con TSH elevada (> 25 mU/L) en muestra de suero del cordón umbilical (screening). II. 48 madres de niños con hipotiroidismo congénito (una madre con antireosis). III (grupo control). 280 madres de niños con TSH normal en muestra de suero del cordón. La frecuencia de Mab fue de 4,8 porciento (11/228) en el grupo I, 6,2 porciento (3/48) en el grupo II y 5,5 porciento (15/274) en el grupo III, sin diferencias significativas entre los grupos. Resultados similares se encontró para los Tab: 2,2 porciento (5/227), 0 porciento (0/48) y 0,4 porciento (1/271) en los grupos I, II y III; y para los TPO: 4,5 porciento (10/223), 2,2 porciento (1/48) y 3,2 porciento (8/253). No se encontraron diferencias significativas en la frecuencia de bocio y los valores medios de TSH y T4 en los diferentes grupos. En conclusión, la presencia materna de los anticuerpos antitiroideos estudiados (Mab, Tab y TPO) no desempeñan una función importante en la génesis de tr-HTSH o CH en el recién nacido


Assuntos
Anticorpos/análise , Hipotireoidismo/congênito , Programas Nacionais de Saúde , Testes de Função Tireóidea , Glândula Tireoide , Tireotropina/análise , Tiroxina/análise
20.
Rev. cuba. endocrinol ; 7(2): 120-4, jul.-dic. 1996.
Artigo em Espanhol | LILACS | ID: lil-182976

RESUMO

En nuestro pais esta prohibido que las madres que ingieren hormonas tiroidea lacten a sus hijos, por su posible repercusion sobre el recien nacido. Observaciones recientes han puesto en duda la necesidad de tal restriccion. Por ello se estudiaron 20 mujeres en los primeros 10 dias del posparto (grupo 1) y 15 entre los 15 y 60 dias (grupo 3) y 20 que ingerian esta hormona en dosis sustitutiva - 120 mg tiroides desecado, 100 g de 1-T4 o 1 tableta de liolevo B- en los primeros 10 dias del posparto (grupo 2) y 15 entre los 15-60 dias (grupo 4). La leche se obtuvo por medio manual o mecanico. Se determinaron T4t y T3r por RIA, previa separacion de la grasa. La ingestion diaria de leche del recien nacido se calculo sobre la base de 400-1 000 mL/dia para los grupos 1 y 2 y de 700 a 1 200 mL/dia para los grupos 3 y 4. Se tomaron como valores de referencia inferiores los limites de sensibilidad del metodo: 0,5 g/dL para T4t y 0,01 g/dL para T3t (cv:10 por ciento y 8m por ciento, respectivamente). La dosis sustitutiva, necesaria para revertir el hipotiroidismo neonatal, es de 10 g/kg/dL de T4 y de 5 g/kg/dL de T3. Se aplico la t de student para 2 muestras independientes. Grupo 1. Concentracion de T4: x < 0,5 g/dL y de T3: x = 0.015 +/- 0,004 g/dL. (0,013-0,032). El RN ingeriria: T4 de 2 a 5 g/d y Te de 0,052 a 0,32 g/d. Grupo 2. Concentracion de T4 : x < 0,5 g/dL y de T3: x= 0,04 +/- 0,21 g/dL (0,013 +/- 0,097). Estos RN ingeririan igual T4 y T3 de 0,052-0,97 g/d. NO se constaron diferencias significativas (p <0,05) entre ambos grupos. Grupo 3. Concentracion de T4: x= 0,52 +/- 0,04 g/dL (0,5-0,64) y de T3: x,0,093 +/- 0,04 g/dL (0,013-0,16). Los ninos tomarian: T4 de 3,5 a 7,7 g/d y T3: 0.091 a 3,5 g/d. Grupo 4. Concentracion de T4: x 0,64 +/- 0,17 g/dL (0,5-1,05) y de T3: x 0,082 +/- 0,058 g/dL (=,013-0,17). La ingestion en estos RN seria de T4: 3,5 a 12,8 g/d y de T3:0,091 a 2,88 g/d. No se constataron diferencias significativas entre estos 2 ultimos grupos asi como tampoco con los grupos 1 y 2 (p < 0,05). Las madres que toman las hormonas tiroidea en dosis sustitutivaa si pueden lactar, por lo tanto, se puede quitar la prohibicion


Assuntos
Leite Humano , Tiroxina/análise , Tri-Iodotironina/análise
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