Meprobamate reduces accuracy of physiological detection of deception.

Normal male subjects attempted to deceive an experimenter recording electrodermal, respiratory, an cardiovascular activity. Those who had ingested a placebo or nothing were detected with statistically significant frequency on the basis of their phasic electrodermal responses, which clearly distinguished them from truthful suspects. That was not the case with deceptive subjects who had ingested 400 milligrams of meprobamate, nor did the examiner detect which subjects had received the drug.

Appetitive and replacement naps: EEG and behavior.

Consistent subjective, behavioral, and electroencephalographic sleep-stage differences were found between afternoon naps of 11 habitual appetitive nappers (who nap lightly for psychological reasons apparently unrelated to reported sleep needs) and 10 replacement nappers (who apparently nap regularly in response to temporary sleep deficits). Both types of naps were compared with naps of 12 confirmed non-nappers.

Examination of the melatonin hypothesis in women exposed at night to EMF or bright light.

It has been hypothesized that the increased incidence of breast cancer in industrial societies is related to greater exposure to power-frequency electric and magnetic fields (EMF) and/or the presence of high levels of light at night (LAN). EMF and LAN are said to reduce circulating levels of the hormone melatonin which, in turn, allows estrogen levels to rise and stimulate the turnover of breast epithelial stem cells and increase the risk for malignant transformation. Three laboratory-based studies, in which a total of 53 healthy young women were exposed at night to EMF or to LAN under controlled exposure conditions, were performed to determine whether such exposures reduce melatonin and are associated with further alterations in estrogen. All-night exposure to industrial-strength magnetic fields (60 Hz, 28.3 microT) had no effect on the blood levels of melatonin or estradiol. In contrast, nocturnal melatonin levels were profoundly suppressed, and the time of peak concentration was significantly delayed in women exposed to LAN, regardless of whether they were in the follicular or luteal phase of the menstrual cycle. These changes, however, were not associated with alterations in point-for-point matching measures of estradiol. Women who chronically secrete high or low amounts of melatonin each night (area-under-curve range: 86-1,296 pg/mL) also did not differ in their blood levels of estradiol. Taken together, these results are consistent with a growing body of evidence which generally suggests that environmental EMF exposure has little or no effect on the parameters measured in this report.

Cardiac autonomic control mechanisms in power-frequency magnetic fields: a multistudy analysis.

Heart rate variability (HRV), a noninvasive indicator of autonomic control of cardiac activity, is predictive of long-term cardiac morbidity and mortality. Epidemiologic research suggests that occupational exposure to power-frequency magnetic fields may be associated with autonomically mediated cardiac mortality. Results from our laboratory studies of humans exposed to 60-Hz magnetic fields overnight, however, are inconsistent. HRV is altered in some studies but not others. To clarify this, the pooled data from seven studies involving 172 men were analyzed to test specific hypotheses concerning this inconsistency. After analysis, we excluded a) measurement drift or instability over time because HRV was stable under sham-exposed conditions across all studies; b) inadequate statistical power or failure to maintain double-blind controls; c) differences in field intensity (28.3 vs. 127.3 microT) or exposure pattern (intermittent versus continuous) as main effects; or d) the inclusion of individuals sensitive to magnetic field exposure in some studies but not others. Four separate analytic techniques failed to identify a valid subpopulation of sensitive individuals. In some studies, however, hourly blood samples were collected using an indwelling venous catheter. HRV alterations occurred during intermittent exposure in these studies (p < 0.05) but not in similar studies without blood sampling. This result suggests a field interaction with modest arousal or disturbance. Because HRV is tightly coupled to electroencephalographic activity during sleep, these results are physiologically plausible and suggest that HRV alterations during exposure to magnetic fields may occur when accompanied by increases in physiologic arousal, stress, or sleep disturbance.

Brain frequency magnetic fields alter cardiac autonomic control mechanisms.

OBJECTIVE: Heart rate variability (HRV) is a noninvasive indicator of sympathetic and vagal cardiovascular control known to be tightly correlated with sleep stages. Recent studies indicate that HRV in humans is altered by nocturnal exposure to power-frequency (60 Hz) magnetic fields. Given the central origin of autonomic cardiac control, we determined if field exposure in the beta(1) EEG/MEG frequency range was a more effective stimulus for HRV alteration than 60 Hz fields, and explored the mechanisms involved. METHODS: Healthy young men were exposed (n=9) overnight to an intermittent magnetic field (16 Hz, 28.3 microTesla, microT), or sham exposed (n=9), under blind test conditions in a laboratory exposure facility. RESULTS: Field exposure was associated (P<0.05) with reduced power in the low band of the HRV frequency spectrum, and with decreases in mean heart rate. Analysis of the timing of the R waves surrounding each on-off transition of the intermittent field revealed no evidence for a direct effect on the cardiac pacemaker. CONCLUSIONS: Magnetic field exposure in the EEG/MEG beta(1) frequency range alters HRV via a CNS effect. Phase-resetting experiments rule out a direct effect on the cardiac pacemaker. Biophysical calculations of the intensity of the electric fields induced in brain versus heart under the present exposure conditions are also consistent with and support a central rather than a peripheral site of action.

Nocturnal magnetic field exposure: gender-specific effects on heart rate variability and sleep.

OBJECTIVE: To determine if controlled exposure to power-frequency magnetic fields alters heart rate variability (HRV) and polysomnographic endpoints in healthy men (n=22) and women (n=24), 40-60 years of age. METHODS: A randomized, double-blind, crossover design was used. Study endpoints collected during all-night exposure to 60 Hz magnetic fields at an occupational intensity (resultant flux density=28.3 microTesla, microT) were compared to similar endpoints obtained under equivalent, counterbalanced, no-exposure (< or =0.2 microT) control conditions. RESULTS: Older men, but not women, exposed to the magnetic fields showed power reductions in the LF band of the HRV frequency spectrum, which is associated with sympathetically-mediated blood pressure and thermoregulatory control (P<0.04). Older women, but not men, exposed to the fields showed a pattern of disrupted sleep, with reductions in the duration of REM sleep (P=0.03), and strong trends for reductions in sleep efficiency (P=0.06) and total sleep time (P=0.06). CONCLUSIONS: The gender-specific effects seen here with older volunteers replicate the results of previous exposure studies with younger men and women.

Evaluation of salivary thiocyanate as an indicator of smoking behavior.

Salivary samples from three placement sites and under stimulated and unstimulated flow-rate conditions were collected from 36 participants (18 smokers, 18 nonsmokers) on each of 3 days. These samples were used to determine the best collection methodology for discriminating smokers from nonsmokers, the reliability of salivary thiocyanate (SCN) over days, and the stability of SCN given varying storage treatments. Results showed that SCN levels were significantly higher in smokers than in nonsmokers, in parotid site collections than either sublingual or mixed collections, and in unstimulated collections. Stimulated, mixed samples were reliable across days and were the best discriminator of smokers and nonsmokers. SCN levels did not differ under varying storage treatments. It is recommended that a standard methodology for collecting stimulated, mixed saliva be used when measuring SCN levels.

Reversal theory and smoking: a state-based approach to ex-smokers' highly tempting situations.

Reversal theory provides a new approach to understanding ex-smokers' behavior during highly tempting situations. Hypotheses derived from the theory were tested in 2 studies of the highly tempting situations of ex-smokers drawn from community smoking cessation programs. Study 1 consisted of interviews with 55 Ss (25 men and 30 women, mean age 37 years) conducted 3 months after cessation. Study 2 consisted of interviews with 104 Ss (45 men and 59 women, mean age 41 years) conducted 6, 9, 12, and 15 months after cessation. All interviews were coded using reversal theory constructs. Results supported the hypotheses that individuals in paratelic or negativistic states were more likely to lapse than individuals in telic/conformist states and that cigarette availability was related to lapses in paratelic, but not telic, states. Reversal theory constructs accurately classified 93% and 85% of the cases, suggesting that the theory provides an improved model for understanding behavior during highly tempting situations.

State-outcome consistency in smoking relapse crises: a reversal theory approach.

Previous investigations of smoking relapse crises have found limited within-subject consistency. Several investigators have suggested that greater consistency might be observed if situations were described phenomenologically. Reversal theory provides one phenomenological framework. Two relapse crises from each of 49 ex-smokers were compared, using reversal theory constructs. Maintaining abstinence in both crises was consistently associated with being in serious-minded (telic) and conformist states. Smoking in both crises was consistently associated with being in playful (paratelic) or negativistic states. Crises with different outcomes occurred in different state combinations. The findings suggest that coping strategies should be state-tailored for optimal effectiveness.

Self-report of circadian type reflects the phase of the melatonin rhythm.

This study examined the relationship between circadian rhythm characteristics of the pineal hormone melatonin and individual differences in circadian type and mood. 95 healthy young men and 22 women were assessed each hour (00:00-07:00 h) for blood levels of melatonin throughout one night in the laboratory. Each subject was assessed for circadian type (morning, afternoon, or evening type) and morning mood (PANAS). Circadian type was strongly related to the melatonin acrophase but not to amplitude or time of year of assessment. Also, morning types evidenced a more rapid decline in melatonin levels after the peak than did evening types. Evening types were younger than were morning types. Female morning types reported more positive affect upon waking than did female afternoon or evening types. Males showed no such discrimination. Age was related to both melatonin acrophase and circadian type but did not explain the relationship between them. The results replicate and extend findings on circadian type and psychological and physiological variables.

Effects of smoking and telic/paratelic dominance on the contingent negative variation (CNV).

Concepts from reversal theory, a general theory of motivation, emotion and action, have recently been shown to be relevant to smoking behavior and smoking cessation. One relevant concept is that of telic and paratelic dominance. Individuals who are paratelic-dominant are playful, spontaneous, and prefer high arousal seeking. Those who are telic-dominant are serious, tend to plan ahead, and prefer low arousal. This led to the hypothesis that smoking might increase the amplitude of the contingent negative variation (CNV) in paratelic-dominant smokers more than in telic-dominant smokers. CNV was obtained using a Go/NoGo reaction time task with a 2 s S1-S2 interval and variable intertrial intervals. S1 indicated whether the subject was to respond to S2 or not. Errors were punished with a burst of white noise. Subjects performed the CNV task three times: after being deprived of smoking for at least 4 h; after sham smoking; and after smoking a cigarette of their own brand. Telic-dominant subjects differed from paratelic-dominant subjects in the relative amplitude of early (1 s) and late (2 s) components of the CNV. Smoking did not differentially affect the dominance groups unless gender was taken into account, and the most striking interactions between smoking and dominance groups were noted for the NoGo trials. As expected, smoking decreased the amplitude of the early component of the NoGo CNV for telic-dominant women, but increased it for paratelic-dominant women; no significant differences were found for the late component. In men, smoking increased the late CNV more for telics than for paratelics, while smoking did not differentially affect the early component.

Human exposure to 60-Hz magnetic fields: neurophysiological effects.

The neurophysiological effects of exposure to power-frequency magnetic fields at two occupationally-relevant intensities were evaluated in a single-blind study with 18 male and 18 female volunteers. Auditory brainstem (BAEP) and somatosensory (SEP) evoked potentials were recorded before, during and after field exposure (duration = 45 min, frequency = 60 Hz, field intensities = 14.1 or 28.3 microtesla, microT), or an equivalent sham-exposure control period. Visual event-related potentials (VEP) to pattern reversal stimuli were also recorded before and after the exposure period. Field exposure had no differential effects on the BAEP, the VEP, or on SEP measures of central conduction time. Men and women showed a similar lack of sensitivity to exposure. The present results do not support the mechanistic hypothesis that the transmission of sensory information to appropriate cortical centers is delayed or distorted by exposure to power-frequency magnetic fields at occupational intensities.

Smoking and EEG power spectra: effects of differences in arousal seeking.

Reversal theory, a general theory of motivation, emotion and action, has recently been shown to predict lapses in smoking cessation. Individuals are less likely to lapse if they are in the telic (serious-minded, arousal avoidant, goal-oriented) state than when they are in the paratelic (playful, arousal seeking, spontaneous) state. The literature indicates that people can smoke in such a way as to either increase or decrease central nervous system arousal; smoking in the telic and paratelic states might therefore differentially affect the resting electroencephalograph, as quantified by Fast Fourier Transform analysis. The basic hypothesis was supported. Theta power was decreased when subjects in the telic state smoked, while beta 2 power was increased when subjects in the paratelic state smoked; the latter finding was, however, true only for men. The results have important implications for research on changing health behaviors and for smoking cessation programs.

The influence of salivary stimulation on the validity of thiocyanate as an index of smoking status.

This study investigated the effects of salivary stimulation on thiocyanate (SCN) levels. A device for collecting parotid saliva that allowed for the measurement of flow rate was used in stimulated and nonstimulated conditions with six subjects. Results indicated that SCN levels exhibited considerable within-subject variability and were inversely related to flow rate. Under stimulated conditions, SCN levels stabilized in 3 min. Under nonstimulated conditions. SCN levels stabilized in 26 min. Although mean SCN levels were higher for smokers than nonsmokers, considerable overlap was observed such that misclassification of both smokers and nonsmokers could occur if cut-off points were not adjusted for flow rate conditions. Suggestions for standardizing stimulated conditions for collecting salivary SCN samples are discussed.

Effects of methanol vapor on human neurobehavioral measures.

Methanol could become an important motor fuel. The objective of this exploratory study was to provide preliminary information about whether or not acute exposure to methanol at 250 mg/m3 for 75 minutes would have adverse effects on human neurobehavioral functions important in everyday life. This concentration level was selected because it is at the upper limit of the traffic scenario estimates provided by the U.S. Environmental Protection Agency (EPA)2 (86 to 240 mg/m3), but is below the maximum concentrations for eight-hour average exposures currently recommended by the National Institute of Occupational Safety and Health (NIOSH) and the American Conference of Government and Industrial Hygienists (ACGIH) (260 mg/m3). Although traffic scenario exposure estimates suggest that such high levels of exposure last less than 15 minutes, we used a 75-minute exposure to increase the probability of identifying dependent measures that should be studied in more detail in a future confirmatory study. Twelve healthy young men, each serving as his own control, participated in two sham exposures and two methanol exposures under counterbalanced, double-blind control conditions. Because methanol is present in many foods, and because high preexposure levels of methanol or formate might obscure exposure effects, subjects were required to strictly limit their diets for 12 hours before each experimental session. The following endpoints were examined before, during, and after exposure to methanol and sham vapors: blood and urinary methanol; plasma formate; oral temperature; blood pressure; subjective mood, alertness, fatigue, workload, and symptom scales; spectral analysis of the electroencephalogram; visual- and auditory-event-related potentials; contingent negative variation; respiration; cardiac interbeat interval; Symbol Digit substitution task; three-choice reaction time; Stroop color-word test; simple reaction time; visual function; critical flicker fusion frequency; hand steadiness; visual search task; Gamberale reaction time task; visual tracking task; Sternberg memory task; interval production task; and speeded addition task. Two dual tasks were also included in the task batteries. These endpoints were selected from those indicated in the literature to be sensitive to solvents, and from those that are widely used in other neurobehavioral test batteries to identify the effects of environmental pollutants. Because the number of endpoints examined was large and the number of subjects was small, procedures designed to reduce the number of statistical tests performed were used. Mean methanol concentration in the exposure room during methanol exposures was 249 mg/m3 (SD +/- 7 mg/m3). Exposure produced significant increases in blood and urine methanol concentration. As expected, no changes in plasma formate were observed.(ABSTRACT TRUNCATED AT 400 WORDS)

Melanotic neuro-ectodermal tumour of infancy. A case report.

A case of melanotic neuro-ectodermal tumour of infancy (retinal anlage tumour, melanotic ameloblastoma) is described. Although a well recognized entity, the biological origin of this tumour is still disputed. A confusing array of names has been awarded to this tumour which characteristically occurs in infants under one year of age, commonly arising from the maxilla but also from the mandible, frontal bone, mediastinum, shoulder and cerebellum. While the origin of the tumour remains unclear, the ultra-structural evidence of Haywood et al. (1969) supports a neural crest origin. Consistent with this are the findings by Borello and Gorlin (1966) of high urinary vanillylmandelic acid excretion in one case and the correlation of tumour enzyme patterns with those of paragangliomas, neuroblastomas and phaeochromocytomas.

Side effects of low-dose pyridostigmine bromide are not related to cholinesterase inhibition.

BACKGROUND: Pretreatment with pyridostigmine bromide (PB) has become part of standard military procedures for protection against the effects of possible chemical warfare attack. The purpose of the work reported here was to quantify the type, intensity and frequency of side effects of low-dose PB, and to examine factors that predict the intensity and frequency of side effects. METHOD: A double-blind, cross-over, placebo (PL)-controlled design was used. Of the 67 subjects, 33 received 30 mg PB every 8 h for 13 doses, and 34 received 60 mg on the same schedule. Order of PB and PL administration was counterbalanced. RESULTS: Overall, side effects were mild, even at the 60-mg dose level. More side effects were reported when volunteers were taking PB than when they were taking placebo. Women reported more symptoms than men. Neither cholinesterase inhibition nor plasma levels of PB predicted side effect scores during the PB week; the best predictor of side effect scores during the PB week was side effect scores during the PL week. CONCLUSION: PB is well tolerated by healthy young people, even when twice the recommended military dose is administered.

Exercise testing in the evaluation of human responses to powerline frequency fields.

The present study used exercise testing to examine the effects of 60-Hz electric and magnetic field exposure. Eleven males, 21-29 years, were tested during four experimental sessions (counterbalanced order and double-blind design). These included either 45-min exercise (50% of VO2 max) or no-exercise periods followed by either real field (9-kV/m, 16-A/m) or sham exposure for 2 h in a 60-Hz human exposure facility. Exercise produced a decrease in plasma volume and increases (p less than 0.05) in lactic acid, cortisol, growth hormone and testosterone levels, but these were not different under real and sham field conditions during the 2-h recovery periods. During no-exercise sessions, cardiac interbeat interval was increased (p less than 0.05), i.e., heart rate was slower, when subjects were exposed to real fields. Our results suggest that future studies should focus on evaluation of the effects of 60-Hz fields on the entire process of exercise-induced activation and recovery.