The Reproducibility and Relative Validity of a Food Frequency Questionnaire for Identifying Iron-Related Dietary Patterns in Pregnant Women.

Analyzing pregnant women's iron intake using dietary patterns would provide information that considers dietary relationships with other nutrients and their sources. The objective of this study was to evaluate the reproducibility and relative validity of a Qualitative Food Frequency Questionnaire to identify iron-related dietary patterns (FeP-FFQ) among Mexican pregnant women. A convenience sample of pregnant women (n = 110) completed two FeP-FFQ (FeP-FFQ1 and FeP-FFQ2) and a 3-day diet record (3DDR). Foods appearing in the 3DDR were classified into the same food groupings as the FeP-FFQ, and most consumed foods were identified. Exploratory factor analysis was used to determine dietary patterns. Scores were compared (FeP-FFQ for reproducibility and FeP-FFQ1 vs. 3DDR for validity) through intraclass correlation coefficients (ICC), cross-classification, Bland−Altman analysis, and weighed Cohen kappa (κw), using dietary patterns scores tertiles. Two dietary patterns were identified: "healthy" and "processed foods and dairy". ICCs (p < 0.01) for "healthy" pattern and "processed foods and dairy" pattern were 0.76 for and 0.71 for reproducibility, and 0.36 and 0.37 for validity, respectively. Cross-classification and Bland−Altman analysis showed good agreement for reproducibility and validity; κw values showed moderate agreement for reproducibility and low agreement for validity. In conclusion, the FeP-FFQ showed good indicators of reproducibility and validity to identify dietary patterns related to iron intake among pregnant women.

Glutathione levels influence chronological life span of Saccharomyces cerevisiae in a glucose-dependent manner.

Diet plays a key role in determining the longevity of the organisms since it has been demonstrated that glucose restriction increases life span whereas a high-glucose diet decreases it. However, the molecular basis of how diet leads to the aging process is currently unknown. We propose that the quantity of glucose that fuels respiration influences reactive oxygen species generation and glutathione levels, and both chemical species impact in the aging process. Herein, we provide evidence that mutation of the gene GSH1 in Saccharomyces cerevisiae diminishes glutathione levels. Moreover, glutathione levels were higher with 0.5% than in 10% glucose in the gsh1Δ and wild-type strains. Interestingly, the chronological life span was lowered in the gsh1Δ strain cultured with 10% glucose but not under dietary restriction. The gsh1Δ strain also showed inhibition of the mitochondrial respiration in 0.5 and 10% glucose but only increased the H2 O2 levels under dietary restriction. These results correlate well with the GSH/GSSG ratio, which showed a decrease in gsh1Δ strain cultured with 0.5% glucose. Together, these data indicate that glutathione exhaustion impact negatively both the electron transport chain function and the chronological life span of yeast, the latter occurring when a low threshold level of this antioxidant is reached, independently of the H2 O2 levels.

Partial recovery of alcohol dependence-related deficits in sleep evoked potentials following 12 months of abstinence.

Stimuli presented during sleep can produce an evoked EEG delta wave referred to as a K-complex. These responses occur when large numbers of cortical cells burst fire in a synchronized manner. Large amplitude synchronized scalp responses require that the CNS contain large numbers of healthy neurons that are interconnected with highly functional white matter pathways. The P2, N550, and P900 components of the evoked K-complex are sensitive measures of normal healthy brain aging, showing a decrease in amplitude with age. N550 and P900 amplitudes are also reduced in recently detoxified alcoholics, most dramatically over frontal scalp regions. The present study tested the hypothesis that the amplitude of K-complex related evoked potential components would increase with prolonged abstinence. Fifteen alcoholics (12 men) were studied twice, separated by a 12 month period, during which time they were followed with monthly phone calls. Subjects were aged between 38 and 60 years at their first study. They had on average a 29.3 ± 6.7 year drinking history and had been abstinent for between 54 and 405 days at initial testing. Evoked K-complexes were identified in the EEG and averaged to enable measurement of the P2, N550 and P900 peaks. Data were collected from seven scalp sites (FP1, FP2, Fz, FCz, Cz, CPz, and Pz). N550 and P900 amplitudes were significantly higher after 12 months of abstinence and an improvement of at least 5 µV occurred in 12 of the 15 subjects. N550 and P900 also showed highly significant site by night interactions with the largest increases occurring over prefrontal and frontal sites. The data indicate that the sleep evoked response may provide a sensitive marker of brain recovery with abstinence from alcohol.

Independent contributions of cortical gray matter, aging, sex and alcoholism to K-complex amplitude evoked during sleep.

STUDY OBJECTIVES: The amplitude of the N550 component derived from the averaged evoked K-complex decreases with normal aging and with alcoholism. The study was designed to determine whether these declines are related to the extent of cortical or subcortical shrinkage. SETTING: Research sleep laboratory and MR imaging facility PARTICIPANTS: 26 abstinent long-term alcoholic men, 14 abstinent long-term alcoholic women, 18 control men, and 22 control women. MEASUREMENTS AND RESULTS: MRI data collected at 3T were analyzed from alcoholic and control men and women previously reported to have significantly different evoked delta activity during sleep. Segmented and parcellated MRI data collected at 3T were compared between these groups and evaluated for correlation with evoked K-complex amplitude measured at FP1, Fz, FCz, Cz, CPz, and Pz. Cortical gray matter and regional subcortical tissue volumes entered as predictors into stepwise multiple regression identified cortical gray matter as a unique significant predictor of evoked K-complex at all sites. Age added independent variance at 5 of the 6 sites, while alcoholism and sex added independent variance at frontal sites only. CONCLUSIONS: These data support recent intracranial studies showing cortical generation of K-complexes by indicating that cortical, but not subcortical volume contributes to K-complex amplitude. Establishing the extent of the relation between cortical volume and K-complex amplitude provides a mechanistic understanding of sleep compromise clinically relevant to normal aging, alcoholism, and likely other conditions affecting cortical volume and integrity.

Developmental change in regional brain structure over 7 months in early adolescence: comparison of approaches for longitudinal atlas-based parcellation.

Early adolescence is a time of rapid change in neuroanatomy and sexual development. Precision in tracking changes in brain morphology with structural MRI requires image segmentation with minimal error. Here, we compared two approaches to achieve segmentation by image registration with an atlas to quantify regional brain structural development over a 7-month interval in normal, early adolescent boys and girls. Adolescents were scanned twice (average interval=7.3 months), yielding adequate data for analysis in 16 boys (baseline age 10.9 to 13.9 years; Tanner Stage=1 to 4) and 12 girls (baseline age=11.2 to 13.7 years; Tanner Stage=3 to 4). Brain volumes were derived from T1-weighted (SPGR) images and dual-echo Fast Spin-Echo (FSE) images collected on a GE 3T scanner with an 8-channel phased-array head coil and analyzed by registration-based parcellation using the SRI24 atlas. The "independent" method required two inter-subject registrations: both baseline (MRI 1) to atlas and follow-up (MRI 2) to the atlas. The "sequential" method required one inter-subject registration, which was MRI 1 to the atlas, and one intra-subject registration, which was MRI 2 to MRI 1. Gray matter/white matter/CSF were segmented in both MRI-1 and MRI-2 using FSL FAST with tissue priors also based on the SRI24 atlas. Gray matter volumes were derived for 10 cortical regions, gray+white matter volumes for 5 subcortical structures, and CSF volumes for 4 ventricular regions and the cortical sulci. Across the 15 tissue regions, the coefficient of variation (CV) of change scores across individuals was significantly lower for the sequential method (CV=3.02), requiring only one inter-subject registration, than for the independent method (CV=9.43), requiring two inter-subject registrations. Volume change based on the sequential method revealed that total supratentorial and CSF volumes increased, while cortical gray matter volumes declined significantly (p<0.01) in anterior (lateral and medial frontal, anterior cingulate, precuneus, and parietal) but not posterior (occipital, calcarine) cortical regions. These volume changes occurred in all boys and girls who advanced a step in Tanner staging. Subcortical structures did not show consistent changes. Thus, longitudinal MRI assessment using robust registration methods is sufficiently sensitive to identify significant regional brain changes over a 7-month interval in boys and girls in early adolescence. Increasing the temporal resolution of the retest interval in longitudinal developmental studies could increase accuracy in timing of peak growth of regional brain tissue and refine our understanding of the neural mechanisms underlying the dynamic changes in brain structure throughout adolescence.

Electrophysiological evidence of enhanced performance monitoring in recently abstinent alcoholic men.

RATIONALE: Chronic alcoholism is associated with mild to moderate cognitive impairment. Under certain conditions, impairment can be ameliorated by invoking compensatory processes. OBJECTIVE: To identify electrophysiological mechanisms of such compensation that would be required to resolve response conflict. METHODS: 14 abstinent alcoholic men and 14 similarly aged control men performed a variation of the Eriksen flanker task during an electroencephalography (EEG) recording to examine whether alcoholics could achieve and maintain control-level performance and whether EEG markers could identify evidence for the action of compensatory processes in the alcoholics. Monitoring processes engaged following a response were indexed by the correct related negativity (CRN) and error related negativity (ERN), two medial-frontal negative event-related potentials. RESULTS: The alcoholics were able to perform at control levels on accuracy and reaction time (RT). Alcoholics generated larger ERN amplitudes following incorrect responses and larger CRNs following correct responses than controls. Both groups showed evidence of post-error slowing. Larger CRN amplitudes in the alcoholics were related to longer RTs. Also observed in the alcoholics was an association between smaller CRN amplitudes and length of sobriety, suggesting a normalization of monitoring activity with extended abstinence. CONCLUSIONS: To the extent that greater amplitude of these electrophysiological markers of performance monitoring indexes greater resource allocation and performance compensation, the larger amplitudes observed in the alcoholic than control group support the view that elevated performance monitoring enables abstinent alcoholics to overcome response conflict, as was evident in their control-level performance.

A method to combine cognitive and neurophysiological assessments of the elderly.

BACKGROUND: The development of better treatments for brain diseases of the elderly will necessitate more sensitive and efficient means of repeatedly assessing an individual's neurocognitive status. AIM: To illustrate the development of an assessment combining episodic memory and working memory tasks with simultaneous electroencephalography and evoked potential (EP) brain function measures. METHODS: Data from matched groups of elderly subjects with mildly impaired episodic verbal memory on neuropsychological tests and those with no objective signs of impairment were used for scale development. An exploratory multivariate divergence analysis selected task performance and neurophysiological variables that best recognized impairment. Discriminant validity was then initially assessed on separate impaired and unimpaired groups. RESULTS: Decreased response accuracy and parietal late positive component EP amplitude in the episodic memory task best characterized impaired subjects. Sensitivity in recognizing impairment in the validation analysis was 89% with 79% specificity (area under the curve = 0.94). Retest reliability was 0.89 for the unimpaired and 0.74 for the impaired validation groups. CONCLUSION: These promising initial results suggest that with further refinement and testing, an assessment combining cognitive task performance with simultaneous neurofunctional measures could eventually provide an important benefit for clinicians and researchers.

Sleep evoked delta frequency responses show a linear decline in amplitude across the adult lifespan.

Aging is associated with many changes in sleep, with one of the most prominent being a reduction in slow wave sleep. Traditional measures of this phenomenon rely on spontaneous activity and typically confound the incidence and amplitude of delta waves. The measurement of evoked K-complexes during sleep, enable separate assessment of incidence and amplitude taken from the averaged K-complex waveform. The present study describes data from 70 normal healthy men and women aged between 19 and 78 years. K-Complexes were evoked using short auditory tones and recorded from a midline array of scalp sites. Significant reductions with age were seen in the amplitude of the N550 component of the averaged waveform, which represents the amplitude of the K-complex, with linear regression analysis indicating approximately 50% of the variance was due to age. Smaller, yet still significant reductions were seen in the ability to elicit K-complexes. The data highlight the utility of evoked K-complexes as a sensitive marker of brain aging in men and women.

The impact of alcoholism on sleep evoked Delta frequency responses.

BACKGROUND: K-complexes (KCs) are evoked delta frequency electroencephalogram (EEG) responses during sleep that occur when large numbers of healthy cortical cells burst fire in a synchronized manner. The KC amplitude and incidence are sensitive measures of normal healthy brain aging. Given the known neurodegenerative consequences of alcohol abuse it was hypothesized that alcoholism would be associated with further KC amplitude and incidence reductions. METHODS: Eighty-four subjects (42 alcoholics) screened for medical, psychiatric, and sleep problems participated. The protocol involved the presentation of auditory stimuli during stage 2 sleep throughout a night in the laboratory. The KCs were identified and averaged, to enable measurement of the P2, N550, and P900 peaks. RESULTS: Compared with control subjects, alcoholic men and women had lower KC incidence (p < .001) and P2 (p < .001), N550 (p < .05), and P900 (p < .05) amplitudes. There was a significant diagnosis x site interaction (p < .001), indicating the group difference was largest at frontal sites. Longer sobriety correlated with increased N550 amplitude (p < .01). CONCLUSIONS: The KC incidence and amplitude were negatively impacted in alcoholic men and women with exacerbation of the normal aging effects, particularly over frontal scalp regions. The observed relationship between improvements in KC measures and increased time of abstinence suggests that these measures might provide a useful marker of brain recovery with continued abstinence from alcohol.

Lapses in a prefrontal-extrastriate preparatory attention network predict mistakes.

Mistakes are common to all forms of behavior but there is disagreement about what causes errors. We recorded electrophysiological and behavioral measures in a letter discrimination task to examine whether deficits in preparatory attention predicted subsequent response errors. Error trials were characterized by decreased frontal-central preparatory attention event-related potentials (ERPs) prior to stimulus presentation and decreased extrastriate sensory ERPs during visual processing. These findings indicate that transient lapses in a prefrontal-extrastriate preparatory attention network can lead to response errors.

Frontal-parietal event-related potential changes associated with practising a novel visuomotor task.

Learning novel visuomotor tasks requires precise processing and transformation of incoming sensory information to produce accurate motor responses. The present study characterized neural activity associated with sensorimotor processes during novel visuomotor learning. We hypothesized that the acquisition of a visuomotor skill would be accompanied by experience-dependent modulation of sensorimotor cortical activity. Subjects controlled a cursor on a computer screen with a joystick. With the goal to move the cursor to a cued target after a brief delay, the relationship between joystick and cursor movement was manipulated such that joystick movement controlled cursor velocity, not displacement (rate task). Individual trials in this task were further divided into early (rate1) and late (rate2) blocks. Event-related potentials (ERPs) were averaged to target presentation, the cue for movement, and movement onset. Subjects were more accurate after practice in late rate2 compared to early rate1 blocks. ERPs associated with movement onset were larger in amplitude and occurred earlier over centroparietal sites following practice. In contrast, ERPs to the cue to move were enhanced frontocentrally initially and diminished with practice. The results suggest that practice on a novel visuomotor task is associated with changes in frontoparietal networks involved in motor preparation and sensorimotor integration. Specifically, practice-related enhancement of movement-related ERPs supports experience-dependent alterations in the network subserving motor preparation.