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1.
Behav Res Ther ; 176: 104522, 2024 May.
Artículo en Inglés | MEDLINE | ID: mdl-38547724

RESUMEN

Individuals experiencing suicidal thoughts and behaviors (STBs) show less specificity and positivity during episodic future thinking (EFT). Here, we present findings from two studies aiming to (1) further our understanding of how STBs may relate to neural responsivity during EFT and (2) examine the feasibility of modulating EFT-related activation using real-time fMRI neurofeedback (rtfMRI-nf). Study 1 involved 30 individuals with major depressive disorder (MDD; half with STBs) who performed an EFT task during fMRI, for which they imagined personally-relevant future positive, negative, or neutral events. Positive EFT elicited greater ventromedial prefrontal cortex (vmPFC) activation compared to negative EFT. Importantly, the MDD + STB group exhibited reduced vmPFC activation across all EFT conditions compared to MDD-STB; although EFT fluency and subjective experience remained consistent across groups. Study 2 included rtfMRI-nf focused on vmPFC modulation during positive EFT for six participants with MDD + STBs. Results support the feasibility and acceptability of the rtfMRI-nf protocol and quantitative and qualitative observations are provided to help inform future, larger studies aiming to examine similar neurofeedback protocols. Results implicate vmPFC blunting as a promising treatment target for MDD + STBs and suggest rtfMRI-nf as one potential technique to explore for enhancing vmPFC engagement.


Asunto(s)
Trastorno Depresivo Mayor , Neurorretroalimentación , Humanos , Neurorretroalimentación/métodos , Ideación Suicida , Trastorno Depresivo Mayor/terapia , Corteza Prefrontal , Imagen por Resonancia Magnética
2.
Gynecol Oncol ; 151(1): 69-75, 2018 10.
Artículo en Inglés | MEDLINE | ID: mdl-30078506

RESUMEN

OBJECTIVE: The Post-Operative Radiation Therapy in Endometrial Carcinoma (PORTEC)-4a trial is a randomized trial for women with high-intermediate risk endometrial cancer (EC), comparing individualized adjuvant treatment based on a molecular-integrated risk profile to standard adjuvant treatment; vaginal brachytherapy. To evaluate patient acceptability and pathology logistics of determining the risk profile, a pilot phase was included in the study. METHODS: PORTEC-4a is ongoing and the first 50 patients enrolled were included in the pilot phase. Primary endpoints of the pilot phase were patient acceptance, evaluated by analyzing the screening logs of the participating centers, and logistical feasibility of determination of the risk profile within 2 weeks, evaluated by analyzing the pathology database. RESULTS: In the first year, 145 eligible women were informed about the trial at 13 centers, of whom 50 (35%) provided informed consent. Patient accrual ranged from 0 to 57% per center. Most common reasons for not participating were: not willing to participate in any trial (43.2%) and not willing to risk receiving no adjuvant treatment (32.6%). Analysis of the pathology database showed an average time between randomization and determination of the molecular-integrated risk profile of 10.2 days (1-23 days). In 5 of the 32 patients (15.6%), pathology review took >2 weeks. CONCLUSIONS: The PORTEC-4a trial design was proven feasible with a satisfactory patient acceptance rate and an optimized workflow of the determination of the molecular-integrated risk profile. PORTEC-4a is the first randomized trial to investigate use of a molecular-integrated risk profile to determine adjuvant treatment in EC.


Asunto(s)
Braquiterapia/métodos , Neoplasias Endometriales/terapia , Recurrencia Local de Neoplasia/terapia , Satisfacción del Paciente , Braquiterapia/efectos adversos , Supervivencia sin Enfermedad , Neoplasias Endometriales/genética , Neoplasias Endometriales/mortalidad , Neoplasias Endometriales/patología , Endometrio/patología , Endometrio/efectos de la radiación , Endometrio/cirugía , Estudios de Factibilidad , Femenino , Humanos , Persona de Mediana Edad , Clasificación del Tumor , Recurrencia Local de Neoplasia/genética , Recurrencia Local de Neoplasia/mortalidad , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Proyectos Piloto , Calidad de Vida , Radioterapia Adyuvante/métodos , Proyectos de Investigación , Medición de Riesgo/métodos , Resultado del Tratamiento , Flujo de Trabajo
3.
Ned Tijdschr Geneeskd ; 157(33): A5779, 2013.
Artículo en Holandés | MEDLINE | ID: mdl-23945431

RESUMEN

OBJECTIVE: In 2008, the Health Council of the Netherlands published an advice on vitamin D supplementation for the elderly. Nevertheless, suspicion arose at the Ministry of Health, Welfare and Sport and the Netherlands Nutrition Centre that vitamin D supplementation in the elderly is still insufficient. We aimed to determine the extent to which general practitioners and elderly care physicians actually followed the advice of the Health Council. DESIGN: Questionnaire study. METHOD: Brief questionnaires were sent to all elderly care physicians in the Netherlands. Some questions were also posed to general practitioners at a network meeting of the Academic Network of GP Practices of the VU University Medical Center in Amsterdam. RESULTS: More than two-thirds of the respondents, both elderly care physicians and general practitioners, are familiar with the guidelines of the Health Council of the Netherlands on vitamin D supplementation in the elderly, but about half do not prescribe vitamin D when the guideline advises to do so. When supplementation is prescribed, about half of the elderly care physicians and a fifth of the general practitioners uses an insufficient dose. CONCLUSION: The guidelines of the Health Council of the Netherlands on vitamin D supplementation in the elderly are not sufficiently followed by elderly care physicians and general practitioners. Awareness of and support for the vitamin D supplementation guidelines among health care providers is still limited.


Asunto(s)
Envejecimiento/fisiología , Fenómenos Fisiológicos Nutricionales del Anciano , Médicos Generales/psicología , Conocimientos, Actitudes y Práctica en Salud , Vitamina D/administración & dosificación , Anciano , Suplementos Dietéticos , Femenino , Servicios de Salud para Ancianos/normas , Servicios de Salud para Ancianos/estadística & datos numéricos , Humanos , Masculino , Política Nutricional , Necesidades Nutricionales , Pautas de la Práctica en Medicina , Encuestas y Cuestionarios , Deficiencia de Vitamina D/prevención & control
4.
J Water Health ; 11(2): 256-66, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23708573

RESUMEN

Molecular methods are increasingly applied for virus detection in environmental samples without rendering data on viral infectivity. Infectivity data are important for assessing public health risks from exposure to human pathogenic viruses in the environment. Here, treatment efficiencies of three (drinking) water treatment processes were estimated by quantification of the indicator virus bacteriophage MS2 with culture and real-time reverse transcription polymerase chain reaction (qRT-PCR). We studied the virus reduction by slow sand filtration at a pilot plant. No decay of MS2 RNA was observed, whereas infectious MS2 particles were inactivated at a rate of 0.1 day(-1). Removal of MS2 RNA and infectious MS2 particles was 1.2 and 1.6 log10-units, respectively. Virus reduction by UV and gamma irradiation was determined in laboratory-scale experiments. The reduction of MS2 RNA based on qRT-PCR data was negligible. Reduction of infectious MS2 particles was estimated at 3.0-3.6 log10-units (UV dose up to 400 or 800 J/m(2)) and 4.7-7 log10-units (gamma dose up to 200 Gray). As shown in this study, estimations of viral reduction, both inactivation and removal, obtained by molecular methods should be interpreted carefully when considering treatment options to provide virus-safe drinking water. Combining culture-based methods with molecular methods may provide supplementary information on mechanisms of virus reduction.


Asunto(s)
Filtración/métodos , Levivirus/efectos de la radiación , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa/métodos , Microbiología del Agua , Filtración/instrumentación , Rayos gamma , Levivirus/fisiología , Dióxido de Silicio , Cultivo de Virus , Purificación del Agua
5.
J Physiol ; 589(Pt 23): 5845-55, 2011 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-22005678

RESUMEN

Magnetic resonance spectroscopy (MRS) allows measurement of neurotransmitter concentrations within a region of interest in the brain. Inter-individual variation in MRS-measured GABA levels have been related to variation in task performance in a number of regions. However, it is not clear how MRS-assessed measures of GABA relate to cortical excitability or GABAergic synaptic activity. We therefore performed two studies investigating the relationship between neurotransmitter levels as assessed by MRS and transcranial magnetic stimulation (TMS) measures of cortical excitability and GABA synaptic activity in the primary motor cortex. We present uncorrected correlations, where the P value should therefore be considered with caution. We demonstrated a correlation between cortical excitability, as assessed by the slope of the TMS input-output curve and MRS-assessed glutamate levels (r = 0.803, P = 0.015) but no clear relationship between MRS-assessed GABA levels and TMS-assessed synaptic GABA(A) activity (2.5 ms inter-stimulus interval (ISI) short-interval intracortical inhibition (SICI); Experiment 1: r = 0.33, P = 0.31; Experiment 2: r = -0.23, P = 0.46) or GABA(B) activity (long-interval intracortical inhibition (LICI); Experiment 1: r = -0.47, P = 0.51; Experiment 2: r = 0.23, P = 0.47). We demonstrated a significant correlation between MRS-assessed GABA levels and an inhibitory TMS protocol (1 ms ISI SICI) with distinct physiological underpinnings from the 2.5 ms ISI SICI (r = -0.79, P = 0.018). Interpretation of this finding is challenging as the mechanisms of 1 ms ISI SICI are not well understood, but we speculate that our results support the possibility that 1 ms ISI SICI reflects a distinct GABAergic inhibitory process, possibly that of extrasynaptic GABA tone.


Asunto(s)
Ácido Glutámico/fisiología , Espectroscopía de Resonancia Magnética , Corteza Motora/fisiología , Estimulación Magnética Transcraneal , Ácido gamma-Aminobutírico/fisiología , Adulto , Electromiografía , Humanos , Masculino , Persona de Mediana Edad , Receptores de GABA-A/fisiología , Receptores de GABA-B/fisiología , Sinapsis/fisiología , Adulto Joven
7.
Hum Reprod ; 22(2): 594-7, 2007 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-17000650

RESUMEN

BACKGROUND: In the near future, a substantial proportion of adults will be childhood cancer survivors. The cryopreservation and transplantation of spermatogonial stem cells (SSCs) is currently successful in animals; application in humans seems likely in the near future. Cryopreserving SSCs might become an important issue in childhood cancer. Because this might require testicular biopsies or hemicastration, parental desire/acceptability for SSC collection was enquired for. METHODS: Three hundred eighteen parents of boys surviving at least 2 years after the diagnosis of cancer were asked about collecting SSCs by biopsy or hemicastration and collecting sperm by masturbation or electrostimulation. Opinions were assessed as if at the time of diagnosis and at the present time. RESULTS: Sixty-three per cent of parents responded. At diagnosis, SSC collection by means of biopsy was approved by 61%, hemicastration by 33% and collecting sperm by 70% (P < 0.013). The acceptability of performing hemicastration was significantly lower than all other forms of SSC/sperm collection. No differences were observed between parents' present opinion and opinion at diagnosis. No differences related to treatment intensity, presumed negative fertility effects and pubertal state were found. CONCLUSIONS: Infertility is a major topic for parents. For prepubertal boys, the collection of SSCs might be a great relief in respect of the fertility issue. Collecting SSCs by biopsy is desired and accepted by the majority of parents; hemicastration is accepted by one-third of parents. The translation of SSC cryopreservation and transplantation from animal models to humans is eagerly awaited.


Asunto(s)
Criopreservación , Infertilidad Masculina/prevención & control , Neoplasias/psicología , Padres/psicología , Aceptación de la Atención de Salud/estadística & datos numéricos , Preservación de Semen/psicología , Espermatogonias/citología , Células Madre/citología , Adolescente , Adulto , Biopsia , Castración/métodos , Niño , Preescolar , Humanos , Lactante , Infertilidad Masculina/etiología , Masculino , Masturbación , Neoplasias/complicaciones , Pubertad
8.
Eur J Clin Nutr ; 61(6): 769-78, 2007 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-17151589

RESUMEN

OBJECTIVE: To determine the effect of folic acid, vitamin B(6) and B(12) fortified spreads on the blood concentrations of these vitamins and homocysteine. DESIGN AND SETTING: A 6-week randomized, double-blinded, placebo-controlled, parallel trial carried out in a clinical research center. SUBJECTS: One hundred and fifty healthy volunteers (50% males). INTERVENTIONS: For 6 weeks, the subjects consumed the test spreads (20 g/day): containing per 20 g (1) 200 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6), or (2) 400 microg folic acid, 2 microg vitamin B(12) and 1 mg vitamin B(6) or (3) no B-vitamins (control spread). RESULTS: The B-vitamin status increased on using the test spreads, with the largest effect on the serum folate concentration: 48% in men and 58% in women on spread 1 and 92 and 146%, respectively, on spread 2 (P-values all <0.05). The plasma homocysteine decreased in the groups treated with the fortified spreads as compared to the control group. Average decreases were for males: 0.7+/-1.5 micromol/l (6.8%) on spread 1 and 1.7+/-1.7 micromol/l (17.6%) on spread 2 and for females: 1.4+/-1.2 micromol/l (14.2%) and 2.4+/-2.0 micromol/l (23.3%), respectively (P-values all <0.05). CONCLUSIONS: Consumption of a spread fortified with folic acid, vitamin B(6) and vitamin B(12) for 6 weeks significantly increases the blood concentrations of these vitamins and significantly decreases the plasma concentration of homocysteine. Fortified staple foods like spreads can contribute to the lowering of homocysteine concentrations.


Asunto(s)
Alimentos Fortificados , Homocisteína/sangre , Hiperhomocisteinemia/dietoterapia , Complejo Vitamínico B/administración & dosificación , Complejo Vitamínico B/sangre , Adolescente , Adulto , Anciano , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Femenino , Ácido Fólico/administración & dosificación , Ácido Fólico/sangre , Humanos , Masculino , Persona de Mediana Edad , Factores Sexuales , Vitamina B 12/administración & dosificación , Vitamina B 12/sangre , Vitamina B 6/administración & dosificación , Vitamina B 6/sangre
9.
Haemophilia ; 12(4): 363-71, 2006 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-16834735

RESUMEN

The management of patients with inhibitors is an important challenge in haemophilia care. The lack of randomized controlled trials means that clinical decisions are generally based on subjective opinions, and purchasers' attention is likely to focus on the costs of treatment. In order to assess the current management of inhibitor patients and use of immune tolerance induction therapy (ITI) in Europe, we performed a survey within a European network of 21 comprehensive care centres from 14 countries (the European Haemophilia Therapy Standardisation Board). The survey identified a total of 381 patients with inhibitors attending the centres, 211 (55.4%) of whom had never been exposed to ITI. Between 1998 and 2003, the centres performed 233 procedures and 114 (48.9%) were successful. The survey demonstrated that dosing, which is the time to start and stop the ITI, the type of concentrate to use and the definition of success varied among the centres. Well-designed trials are warranted to guide decision-making, but in the absence of these studies we have developed consensus guidance for the management of inhibitor patients based on current clinical practice, as identified by the survey, and review of the literature.


Asunto(s)
Inhibidores de Factor de Coagulación Sanguínea/sangre , Factor IX/uso terapéutico , Factor VIII/uso terapéutico , Hemofilia A/tratamiento farmacológico , Hemofilia B/tratamiento farmacológico , Adulto , Niño , Esquema de Medicación , Europa (Continente) , Medicina Basada en la Evidencia , Factor IX/antagonistas & inhibidores , Factor IX/inmunología , Factor VIII/antagonistas & inhibidores , Factor VIII/inmunología , Encuestas de Atención de la Salud , Hemofilia A/inmunología , Hemofilia B/inmunología , Humanos , Tolerancia Inmunológica , Isoanticuerpos/sangre , Masculino , Práctica Profesional/estadística & datos numéricos , Resultado del Tratamiento
10.
Disabil Rehabil ; 28(9): 595-602, 2006 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-16690589

RESUMEN

PURPOSE: Within the context of taking the perspectives of disabled individuals themselves more seriously, it is imperative that researchers and practitioners accord due primacy to the experiential worlds and everyday lived experiences of individuals with disabilities. Based on the premise that theoretical groundedness (along with methodological rigour) is integral to sound research, it is argued that the existing body of knowledge regarding the lived experiences of individuals with disabilities may be complemented by a conceptual placing of understandings of disability in relation to a prominent theoretical pathway at the moment, namely, the interdisciplinary emphasis on human strengths and wellness. METHOD: A critical engagement with key conceptualizations of disability entailed a focus on the development, strengths, and challenges of medical, social and psychologically based conceptualizations of disability. RESULTS AND CONCLUSION: The existing body of knowledge around disability may be extended and complemented by key concepts regarding human health/wellness from the field of Positive Psychology. Positive Psychology's keynote contribution to the study of disability and rehabilitation entails directing researchers and practitioners to the aim of building, reinforcing and extending disabled individuals' strengths and capacities in order to optimize their functioning in all areas of life, and thereby promote wellness.


Asunto(s)
Personas con Discapacidad/psicología , Personas con Discapacidad/rehabilitación , Promoción de la Salud , Parálisis Cerebral/psicología , Parálisis Cerebral/rehabilitación , Preescolar , Formación de Concepto , Salud Holística , Humanos , Teoría Psicológica , Investigación
11.
Int J Oral Maxillofac Surg ; 35(9): 865-9, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16584870

RESUMEN

Central giant cell granuloma (CGCG) is a benign lesion of the jaws with a sometimes locally aggressive behaviour. The most common therapy is surgical curettage which has a high recurrence rate, especially in lesions with aggressive signs and symptoms (i.e. pain, paresthesia, root-resorption and rapid growth). Alternative therapies such as interferon alpha (INFalpha) or calcitonin are described in the literature. In this study 2 patients with an aggressive CGCG are presented who were treated with INF mono-therapy. INF mono-therapy was capable of terminating the rapid growth of the lesion in both patients and induced a partial reduction. Total resolution, however, was not obtained and alternative treatment is still necessary.


Asunto(s)
Granuloma de Células Gigantes/tratamiento farmacológico , Interferón-alfa/uso terapéutico , Enfermedades Mandibulares/tratamiento farmacológico , Enfermedades Maxilares/tratamiento farmacológico , Adolescente , Adulto , Conservadores de la Densidad Ósea/administración & dosificación , Conservadores de la Densidad Ósea/uso terapéutico , Calcitonina/uso terapéutico , Femenino , Granuloma de Células Gigantes/diagnóstico por imagen , Humanos , Interferón-alfa/administración & dosificación , Masculino , Mandíbula/diagnóstico por imagen , Enfermedades Mandibulares/diagnóstico por imagen , Maxilar/diagnóstico por imagen , Enfermedades Maxilares/diagnóstico por imagen , Radiografía , Inducción de Remisión/métodos , Insuficiencia del Tratamiento
13.
Neuroimage ; 30(1): 220-7, 2006 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-16271482

RESUMEN

Functionally significant landmarks in the brain do not necessarily align with local sulcal and gyral architecture in a manner that is consistent across individuals. However, the functional specialisation underlying these landmarks is strongly constrained by the connectional architecture of the region. Here, we explore this relationship in the supplementary motor area (SMA) and pre-SMA in the medial frontal cortex of the human brain. Using diffusion tensor, conventional and functional MR imaging, we find that the location of the functional boundary between SMA and preSMA is more consistent with respect to specific features of the local white matter as it approaches neocortex than with respect to the local gyral and sulcal anatomy in the region.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Lóbulo Frontal/fisiología , Aumento de la Imagen , Procesamiento de Imagen Asistido por Computador , Imagen por Resonancia Magnética , Corteza Motora/fisiología , Vías Nerviosas/fisiología , Oxígeno/sangre , Adulto , Mapeo Encefálico , Imagen Eco-Planar , Femenino , Lóbulo Frontal/anatomía & histología , Humanos , Masculino , Corteza Motora/anatomía & histología , Vías Nerviosas/anatomía & histología , Tractos Piramidales/anatomía & histología , Tractos Piramidales/fisiología , Valores de Referencia , Tálamo/anatomía & histología , Tálamo/fisiología
14.
Eur J Clin Nutr ; 59(8): 906-13, 2005 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-15928685

RESUMEN

OBJECTIVE: The aim of this study was to investigate whether milk fortified with folic acid enhances the folate status of humans and whether the presence of folate-binding proteins (FBP) in pasteurised milk affects the bioavailability of folic acid from fortified milk. In untreated and pasteurised milk, folate occurs bound to FBP, while FBP is (partly) denatured in ultra-high-temperature (UHT)-treated milk. The effect of FBP on folate bioavailability is still unclear. DESIGN, SUBJECTS AND SETTING: Healthy, free-living subjects (n=69) aged 18-49 y participated in a 4-week double-blind, placebo-controlled dietary intervention study. INTERVENTION: In addition to a fully controlled diet, the subjects consumed each day 500 ml of pasteurised or UHT milk, either fortified or not with 200 mug folic acid. RESULTS: Consumption of fortified milk increased folate concentrations in serum and in red blood cells (RBC) by 6.6-7.0 nmol/l (P<0.001) and 32-36 nmol/l (P<0.01), respectively. Similarly, plasma homocysteine concentrations were lowered 0.88-0.89 micromol/l (P=0.001) in subjects who consumed fortified milk. The bioavailability of folic acid from pasteurised milk relative to that of folic acid from UHT milk was 74-94% (NS), depending on the parameter used. CONCLUSIONS: Milk fortified to supply an additional 200 microg of folic acid/s substantially increased folate status, and decreased plasma total homocysteine concentrations in young, healthy subjects. Milk is therefore a suitable matrix for fortification to enhance the folate status in humans. No significant effect of endogenous FBP was found on the bioavailability of folic acid from milk.


Asunto(s)
Proteínas Portadoras/metabolismo , Ácido Fólico/farmacocinética , Manipulación de Alimentos/métodos , Alimentos Fortificados , Leche/química , Receptores de Superficie Celular/metabolismo , Adolescente , Adulto , Animales , Disponibilidad Biológica , Método Doble Ciego , Eritrocitos/química , Femenino , Receptores de Folato Anclados a GPI , Ácido Fólico/metabolismo , Alimentos Fortificados/análisis , Homocisteína/sangre , Humanos , Masculino , Persona de Mediana Edad , Defectos del Tubo Neural/prevención & control
15.
J AOAC Int ; 88(1): 5-15, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15759720

RESUMEN

In 1996, U.S. Food and Drug Administration regulations mandated the fortification of enriched cereal-grain products with folic acid, thereby emphasizing the need for validated methods for total folates in foods, particularly cereal products. The AOAC Official Methods (944.12, 960.46) currently used for the analysis of folate in foods for compliance purposes are microbiological methods. When the fortification regulations were finalized, no Official AOAC or Approved AACC methods for folate in cereal-grain products were in place. The AOAC Official Method (992.05) for folic acid in infant formula does not incorporate important improvements in the extraction procedure and was not considered suitable for the analysis of folates in foods in general. A microbiological assay protocol using a trienzyme extraction procedure was prepared and submitted for comments to 40 laboratories with recognized experience in folate analysis. On the basis of comments, the method was revised to have the conjugase (gamma-glutamyl-carboxy-peptidase) treatment follow a protease treatment, to include the use of cryoprotected inoculum, and to include the spectroscopic standardization of the standard and optional use of microtiter plates. Thirteen laboratories participated in a collaborative study of 10 required and 10 optional cereal-grain products, including flour, bread, cookies, baking mixes, and ready-to-eat breakfast cereals. The majority of the participating laboratories performed the assay by the standard test tube method; others used the microtiter plate modification for endpoint quantitation with equal success. For the required products, the relative standard deviation between laboratories (RSD(R)) ranged from 7.4 to 21.6% for 8 fortified (or enriched) products compared with expected (Horwitz equation-based) values of 11-20%. RSD(R) values were higher (22.7-52.9%) for 2 unfortified cereal-grain products. For the optional products, the RSD(R) ranged from 1.8 to 11.2% for 8 fortified products. RSD(R) values were higher (27.9-28.7%) for 2 unfortified cereal-grain products. Based on the results of the collaborative study, the microbiological assay with trienzyme extraction is recommended for adoption as Official First Action.


Asunto(s)
Técnicas de Química Analítica/métodos , Grano Comestible/metabolismo , Análisis de los Alimentos/métodos , Alimentos Fortificados , Lactobacillus/metabolismo , Espectrofotometría/métodos , Automatización , Pan , Ácido Fólico/análisis , Ácido Fólico/química , Deficiencia de Ácido Fólico/prevención & control , Guías como Asunto , Humanos , Concentración de Iones de Hidrógeno , Laboratorios , Nefelometría y Turbidimetría , Política Nutricional , Oxígeno/metabolismo , Control de Calidad , Reproducibilidad de los Resultados
16.
Magn Reson Med ; 50(5): 1077-88, 2003 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-14587019

RESUMEN

A fully probabilistic framework is presented for estimating local probability density functions on parameters of interest in a model of diffusion. This technique is applied to the estimation of parameters in the diffusion tensor model, and also to a simple partial volume model of diffusion. In both cases the parameters of interest include parameters defining local fiber direction. A technique is then presented for using these density functions to estimate global connectivity (i.e., the probability of the existence of a connection through the data field, between any two distant points), allowing for the quantification of belief in tractography results. This technique is then applied to the estimation of the cortical connectivity of the human thalamus. The resulting connectivity distributions correspond well with predictions from invasive tracer methods in nonhuman primate.


Asunto(s)
Imagen de Difusión por Resonancia Magnética , Algoritmos , Anisotropía , Humanos , Procesamiento de Imagen Asistido por Computador , Modelos Estadísticos , Tálamo/anatomía & histología
17.
Nat Neurosci ; 6(7): 750-7, 2003 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-12808459

RESUMEN

Evidence concerning anatomical connectivities in the human brain is sparse and based largely on limited post-mortem observations. Diffusion tensor imaging has previously been used to define large white-matter tracts in the living human brain, but this technique has had limited success in tracing pathways into gray matter. Here we identified specific connections between human thalamus and cortex using a novel probabilistic tractography algorithm with diffusion imaging data. Classification of thalamic gray matter based on cortical connectivity patterns revealed distinct subregions whose locations correspond to nuclei described previously in histological studies. The connections that we found between thalamus and cortex were similar to those reported for non-human primates and were reproducible between individuals. Our results provide the first quantitative demonstration of reliable inference of anatomical connectivity between human gray matter structures using diffusion data and the first connectivity-based segmentation of gray matter.


Asunto(s)
Corteza Cerebral/anatomía & histología , Imagen de Difusión por Resonancia Magnética/métodos , Vías Nerviosas/anatomía & histología , Tálamo/anatomía & histología , Adulto , Mapeo Encefálico , Corteza Cerebral/fisiología , Femenino , Humanos , Masculino , Vías Nerviosas/metabolismo , Probabilidad , Reproducibilidad de los Resultados , Tálamo/fisiología
18.
Ned Tijdschr Geneeskd ; 147(16): 752-6, 2003 Apr 19.
Artículo en Holandés | MEDLINE | ID: mdl-12731465

RESUMEN

A balanced diet based on the Guidelines of the Netherlands Nutrition Centre provides a suitable basis for the maintenance of good health. However, there are a number of situations where supplementation with vitamins is clearly indicated. These include infants (vitamin A, D and K), young children, and pregnant and lactating women (vitamin D), future expectant mothers (folic acid) and the elderly (vitamin D). If doubts exist about a sufficient vitamin intake via the regular diet, a daily supplement supplying all vitamins at the level of the recommended daily allowance (RDA) is considered to be a responsible and safe choice. Epidemiological research indicates that the incidence of certain diseases is lower if the intake of vitamins is significantly higher than the RDA. However to date, targeted intervention studies have provided little unequivocal evidence to support this argument. For certain vitamins (A, D, folic acid, B6, nicotinic acid and beta-carotene) excessive intakes are associated with a health risk or clear toxicity. In the case of vitamin B6, nicotinic acid, folic acid and beta-carotene this risk is mainly limited to the use of high-dose supplements.


Asunto(s)
Dieta/normas , Suplementos Dietéticos , Salud , Vitaminas/administración & dosificación , Factores de Edad , Femenino , Humanos , Masculino , Países Bajos , Política Nutricional , Estado Nutricional , Valor Nutritivo , Vitaminas/efectos adversos
19.
J Nutr ; 131(12): 3197-203, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11739865

RESUMEN

The objectives of the present study were to compare the bioavailability of vitamin A from liver paste and from a vitamin A supplement at three nutritionally relevant levels of intake, and to estimate levels of "safe" intake based on concentrations of retinoic acid and its metabolites in plasma after a single dose of vitamin A from liver paste. Women (n = 35; 19-47 y of age) consumed 3.0, 7.5 or 15 mg vitamin A as liver paste or as a vitamin A supplement with a test meal in a randomized design, with a combined crossover (two sources) and parallel approach (three dosages). Retinyl esters and retinoic acid (RA) metabolites were quantified in blood samples at 2-24 h after dosing. The areas under the time-response curves (AUC) were calculated to evaluate responses in plasma vitamin A after intake of liver paste and the vitamin A supplements. For retinyl esters, the AUC was significantly affected by the dosage, but not by the source. The formation of 13-cis-RA, 13-cis-4-oxo-RA, and to a lesser extent all-trans-RA was significantly higher after consumption of liver paste compared with the supplement, especially at higher dosages. Long-term baseline concentrations of retinol were not affected by a single intake of vitamin A. In conclusion, the bioavailability of vitamin A from single doses of liver paste and a vitamin A supplement does not differ, but the plasma concentrations of RA metabolites are higher after intake of liver paste. Thus, pregnant women should indeed limit the intake of vitamin A from liver products.


Asunto(s)
Dieta , Hígado , Tretinoina/sangre , Vitamina A/administración & dosificación , Adulto , Disponibilidad Biológica , Estudios Cruzados , Suplementos Dietéticos , Femenino , Humanos , Persona de Mediana Edad , Embarazo , Vitamina A/efectos adversos , Vitamina A/farmacocinética
20.
J Am Coll Nutr ; 20(3): 232-8, 2001 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-11444419

RESUMEN

OBJECTIVE: The objective of this study was to determine the effect of individual carotenoid supplementation on biochemical indices of oxidative status in apparently healthy adult males. METHODS: The study was a placebo controlled single blind study. Healthy male volunteers (n= 175) were assigned to four groups. They received daily supplements of beta-carotene (15 mg), lutein (15 mg), lycopene (15 mg) and placebo for three months. The effects of the supplementation on antioxidant status were monitored by plasma carotenoid, vitamin C and A levels, glutathione (GSH and GSSG) concentrations, protein SH groups. erythrocyte antioxidant enzyme activities (Cu-Zn SOD, Se-GSH-Px) and susceptibility of LDL to copper-induced oxidation. RESULTS: beta-carotene, lycopene and lutein supplementation led to significant plasma and LDL increases in each of these carotenoids, without modifications of other carotenoid levels in plasma or in LDL. The supplementation failed to enhance the resistance of LDL to oxidation or to modify the LDL polyunsaturated/ saturated fatty acid ratio. Vitamin C, GSH, protein SH groups and antioxidant metalloenzyme activities were also unchanged. CONCLUSION: We did not observe beneficial or adverse effects of lutein, lycopene or beta-carotene supplementation on biomarkers of oxidative stress. In apparently healthy subjects, carotenoid supplementation does not lead to significantly measurable improvement in antioxidant defenses.


Asunto(s)
Antioxidantes/administración & dosificación , Carotenoides/administración & dosificación , Lipoproteínas LDL/metabolismo , Estrés Oxidativo/efectos de los fármacos , Adulto , Biomarcadores/sangre , Carotenoides/sangre , Suplementos Dietéticos , Humanos , Peroxidación de Lípido , Luteína/administración & dosificación , Luteína/sangre , Licopeno , Masculino , Oxidación-Reducción , beta Caroteno/administración & dosificación , beta Caroteno/sangre
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