ERP and behavioral changes during the wake/sleep transition

Event-related potentials (ERPs) following infrequent and frequent stimuli were studied as subjects moved from wakefulness to sleep. Subjects were instructed to respond to the infrequent “target” stimuli (attend condition) or to ignore the stimuli (ignore condition). Parietal P300, prominent following target ERPs in wakefulness under the attend condition, disappeared in association with reduced behavioral responsiveness and emergence of a central negativity (N350). The N350 and preceding and following positivities (P220 and P450) became the dominant feature of both target and nontarget ERPs under both attend and ignore conditions. The P220-N350-P450 complex was larger and peak latencies were shorter under the attend condition. Peak amplitudes tended to be larger following targets, especially under the attend condition. The findings suggest that, although the processes under-lying P300 are less likely to be engaged, processing of stimulus deviance and task relevance continues in sleepiness and sleep, and is reflected by variance in N350 and related activity.     

Arousal thresholds during human tonic and phasic REM sleep

The goal of the present study was to investigate arousal thresholds (ATs) in tonic and phasic episodes of rapid eye movement (REM) sleep, and to compare the frequency spectrum of these sub‐states of REM to non‐REM (NREM) stages of sleep. We found the two REM stages to differ with regard to behavioural responses to external acoustic stimuli. The AT in tonic REM was indifferent from that in sleep stage 2, and ATs in phasic REM were similar to those in slow‐wave sleep (stage 4). NREM and REM stages of similar behavioural thresholds were distinctly different with regard to their frequency pattern. These data provide further evidence that REM sleep should not be regarded a uniform state. Regarding electroencephalogram frequency spectra, we found that the two REM stages were more similar to each other than to NREM stages with similar responsivity. Ocular activity such as ponto‐geniculo‐occipital‐like waves and microsaccades are discussed as likely modulators of behavioural responsiveness and cortical processing of auditory information in the two REM sub‐states.     

Malnutrition and Clinical Outcomes: The Case for Medical Nutrition Therapy

Malnutrition is not a new or a rare problem. In studies involving more than 1,327 hospitalized adult patients, 40% to 55% were found to be either malnourished or at risk for malnutrition, and up to 12% were severely malnourished. Surgical patients with likelihood of malnutrition are two to three times more likely to have minor and major complications as well as increased mortality; and their length of stay can be extended by 90% compared with the stay of well-nourished patients. Hospital charges are reported to be from 35% to 75% higher for malnourished patients than for well-nourished patients. Obtaining data to assess the nutritional status of patients is essential to optimal patient care, especially for patients at high risk for malnutrition. Nutrition assessment can be done with readily available and relatively inexpensive methods. But it is not enough to assess and identify malnutrition. Outcomes are improved and costs are saved only when appropriate intervention follows. This article identifies many well-conducted, published studies that support the findings that health outcomes of malnourished patients can be improved and that overall use of resources can be reduced by nutrition counseling, oral diet and oral supplements, enteral formula delivered via tube, and parenteral nutrition support via central or peripheral line. Early nutrition assessment and appropriate nutrition intervention must be accepted as essential for the delivery of quality health care. Appropriately selected nutrition support can address the problem of malnutrition, improve clinical outcomes, and help reduce the costs of health care. J Am Diet Assoc. 1996; 96:361-366,369.     

Subchronic Feeding Study of the Mycotoxin Fumonisin B1 in B6C3F1 Mice and Fischer 344 Rats

Fumonisin B1 (FB1) is a mycotoxin produced by Fusarium moniliforme,a common fungus which occurs naturally on corn, and other Fusariumspecies. FB1 and other fumonisins are now recognized as havingpotentially important animal and human health implications.However, few toxicological data are currently available. Maleand female B6C3F1 mice and Fischer 344 rats were fed diets containing0, 1, 3, 9, 27, or 81 ppm FB1 (98% purity) for 13 weeks. Nodifferences in behavior or appearance, body weight or food consumptionbetween control and FB1-fed groups were found. In mice, hepatopathyand altered serum chemical profiles indicative of hepatotoxicitywere found in females fed the 81 ppm diet. No adverse effectswere found in female mice fed 27 ppm FB1 or in male mice atany dietary level studied. In rats, nephrosis involving theouter medulla was found in males fed 9 ppm and, to a lesserdegree, in females fed 81 ppm FB1, while decreased kidney weightwas found in both sexes at dietary levels 9 ppm FB1. Althoughthe liver is a target organ of FB1 in rats, hepatotoxicity wasnot found in rats fed diets containing up to 81 ppm FB1 for90 days. Thus, FB1 was toxic to both species following subchronicoral exposure, although significant interspecies differencesin the no observed effect levels and organ-specific responseswere found.     

The Wessex Growth Study: First Report

Voss, L., Walker, J., Lunt, H., Wilkin, T. and Betts, P. (Department of Paediatrics and the Endocrine Section, Department of Medicine II, General Hospital, Southampton, UK). The Wessex growth study: first report. Acta Paediatr Scand [Suppl] 349: 65, 1989.
The Wessex Growth Study is a community-based longitudinal survey of short children recruited from two Health Districts in Wessex during 1985–86 (cohort I) and 1986–87 (cohort II). Screening of new school entrants during 1985–86 identified only 1.3% who were at or below the 3rd centile for height as defined by Tanner and Whitehouse, suggesting a strong secular trend and an urgent need for updated height charts. After exclusion of the small number of children with underlying organic pathology and those from ethnic minorities, there were 84 children in cohort I on whom this report is based. These apparently normal, short children were sex- and age-matched with normal controls (10th-90th centile) from the same school class. Forty-two per cent of cohort I had a delayed bone age, and 34% lay above the 3rd centile after correction for parental height. Forty-four per cent were of low birth weight. The correlation between two successive height velocities measured at 6 and 12 months was only -0.14 for cohort I and -0.15 for their controls. Twelve-month mean height velocity SD scores (SDS) were -0.45 and +0.25, respectively, corresponding to the 33rd and 60th centiles, and rather higher than the 25th and 50th centiles expected in view of the heights of these children. Thirty-eight per cent of cohort 1 had a 12-month height velocity below the 25th centile, and in 16% height velocity was below the 10th centile. As a group, the children in cohort I grew more slowly than their controls, hut the height velocity in 88% of cases lay within the control range. For any individual, therefore, 12-month height velocity was not a useful discriminant of growth failure. Repeated measurements are indicated.