Assessing elemental mercury vapor exposure from cultural and religious practices.

Use of elemental mercury in certain cultural and religious practices can cause high exposures to mercury vapor. Uses include sprinkling mercury on the floor of a home or car, burning it in a candle, and mixing it with perfume. Some uses can produce indoor air mercury concentrations one or two orders of magnitude above occupational exposure limits. Exposures resulting from other uses, such as infrequent use of a small bead of mercury, could be well below currently recognized risk levels. Metallic mercury is available at almost all of the 15 botanicas visited in New York, New Jersey, and Pennsylvania, but botanica personnel often deny having mercury for sale when approached by outsiders to these religious and cultural traditions. Actions by public health authorities have driven the mercury trade underground in some locations. Interviews indicate that mercury users are aware that mercury is hazardous, but are not aware of the inhalation exposure risk. We argue against a crackdown by health authorities because it could drive the practices further underground, because high-risk practices may be rare, and because uninformed government intervention could have unfortunate political and civic side effects for some Caribbean and Latin American immigrant groups. We recommend an outreach and education program involving religious and community leaders, botanica personnel, and other mercury users.

Evaluating the effectiveness of risk-reduction strategies for consumer chemical products.

Communication about risks offers a voluntary approach to reducing exposure to pollutants. Its adequacy depends on its impact on behavior. Estimating those impacts first requires characterizing current activities and their associated risk levels, and then predicting the effectiveness of risk-reduction strategies. Characterizing the risks from chemical consumer products requires knowledge of both the physical and the behavioral processes that influence exposures. This article presents an integrated approach that combines consumer interviews, users' beliefs and behaviors, and quantitative exposure modeling. This model was demonstrated in the context of consumer exposure to a methylene chloride-based paint stripper, showing how it could be used to evaluate current levels of risk and predict the effectiveness of proposed voluntary risk-reduction strategies.

Modeling methylene chloride exposure-reduction options for home paint-stripper users.

Home improvement is a popular activity, but one that can also involve exposure to hazardous substances. Paint stripping is of particular concern because of the high potential exposures to methylene chloride, a solvent that is a potential human carcinogen and neurotoxicant. This article presents a general methodology for evaluating the effectiveness of behavioral interventions for reducing these risks. It doubles as a model that assesses exposure patterns, incorporating user time-activity patterns and risk-mitigation strategies. The model draws upon recent innovations in indoor air-quality modeling to estimate exposure through inhalation and dermal pathways to paint-stripper users. It is designed to use data gathered from home paint-stripper users about room characteristics, amount of stripper used, time-activity patterns and exposure-reduction strategies (e.g., increased ventilation and modification in the timing of stripper application, scraping, and breaks). Results indicate that the effectiveness of behavioral interventions depends strongly on characteristics of the room (e.g., size, number and size of doors and windows, base air-exchange rates). The greatest simple reduction in exposure is achieved by using an exhaust fan in addition to opening windows and doors. These results can help identify the most important information for product labels and other risk-communication materials.

Propositional and response processes as distinguishable and equally important aspects of conditioning: some clarifications.

Martin and Levey's (1988) commentary on our 1987 chapter points to the need for clearer definition of terms and much more open debate in the area of learning and conditioning. While raising some good points for further discussion, their characterisation of some issues appears to be based on a number of misinterpretations and misrepresentations of our position, and we attempt here to correct these functions. Issues which we regard as misinterpreted are those of truth value as a criterion of the cognitive, the epistemological status of a cognition as opposed to the object of the cognition, and the nature of propositional versus non-propositional learning theories. Issues which are misrepresented are those of our position on the nature of conditioning (which is called cognitive by Martin and Levey, but which is, in fact, a dual-process view), formal versus content-oriented distinctions, and the nature of human and non-human learning processes. Despite these differences between Martin and Levey and ourselves, it is apparent that such debates are necessary for furthering our understanding of the complexity and multiplicity of the processes involved in learning.

The reliability of alcohol abusers' self-reports of drinking and life events that occurred in the distant past.

This study investigated the test-retest reliability of 69 alcohol abusers' current reports about their past (approximately 8 years prior to interview) drinking behavior and life events. Drinking behavior was assessed by the Lifetime Drinking History (LDH) questionnaire and life events were assessed using the Recent Life Changes Questionnaire (RLCQ). Reliability coefficients for LDH variables were generally moderate to high (r = .52 to .81). Using empirical criteria, the diagnostic power of the two LDH interviews to classify correctly subjects as either having had or not having had a drinking problem was quite high. The reliability coefficient for the RLCQ was r = .85 and 91.7% of the identified events were reported in both interviews. Similarly high test-retest reliabilities and individual event agreement rates were obtained for the six homogeneous subscales of the RLCQ. Subjects were also asked why they had given inconsistent answers to life events questions in the two interviews. Inconsistencies often resulted from errors in the temporal placement of events or from misunderstanding items, rather than from failure to recall an event; this suggests that some sources of error in recalling life events can be reduced. It is concluded that alcohol abusers' reports of drinking and life events occurring many years prior to the date of interview are generally reliable. This finding is consistent with previous studies showing high test-retest reliabilities for reports of recent drinking and related events.

Effect of television programming and advertising on alcohol consumption in normal drinkers.

The drinking behavior of 96 male normal drinking college students was assessed after they viewed a videotape of a popular prime-time television program complete with advertisements. Different versions of the videotape were used to evaluate the effects of a television program with and without alcohol scenes as crossed with the effects of three different types of advertisements (i.e., beer, nonalcoholic beverages and food). After viewing the videotape, the subjects, who were led to believe that they were participating in two separate and unrelated sets of experimental procedures, were asked to perform a taste rating of light beers, which actually provided an unobtrusive measure of their alcohol consumption. The results provided no support for the widely held assumption that drinking scenes in television programs or televised advertisements for alcoholic beverages precipitate increased drinking by viewers. This finding, however, must be considered in the context of the laboratory setting of the study, and thus may not generalize to real-life television viewing. Further research in this area is clearly needed, including an evaluation of the effects of television program content and advertisements on other populations (e.g., alcohol abusers).

Effects of ethanol on eye movements in the monkey.

Ethanol (0.25-2.0 g/kg) was administered by remotely controlled intravenous infusion to monkeys engaged in performance of a short-term memory task which required attention to and retention of visual stimuli. Eye movements were monitored and measured by recording the electrooculogram with implanted periorbital Ag/AgCl electrodes. Ethanol induced the following dose-dependent changes of ocular motility: (a) diminution of the frequency of saccades; (b) prolongation of fixation (immobility) periods, though stimulus-elicited fixations became shorter; (c) increase in saccade excursion; (d) increase in saccade duration; and (e) decrease in saccade velocity (preceded at low doses by a transient increase). These changes were correlated with an impairment of behavioral performance. The results of eye movement analysis complement the results obtained on studies of human subjects by oral administration of ethanol. The findings of the present study in the nonhuman primate are interpreted as a reflection of the deleterious effects of alcohol on the cerebral substrate of visual attention.

Hypercalcemia in the etiology of puerperal psychosis.

The serum calcium of 53 recently delivered mothers hospitalized for severe puerperal psychiatric illness, which represented the whole intake from a defined catchment area, was compared with that of 35 female psychiatric patients and that of 49 normal postnatal women. The mean corrected and ionized serum calcium values of the puerperal psychiatric patients with no personal or family history of psychiatric disorder were markedly above the normal range. They were also significantly higher than those of the puerperal psychiatric patients with a personal or family history of psychiatric illness and those of the two control groups. There was a modest positive correlation between the degree of hypercalcemia and the severity of the psychiatric illness. The follow-up of 16 puerperal psychiatric patients indicated that the fall in ionized serum calcium levels correlated positively and significantly with the improvement in rated symptomatology. Patients with severe puerperal psychiatric disorder can be divided etiologically into two groups. The larger proportion is psychiatrically vulnerable, but in the remainder (about a third of the total number), the psychiatric illness appears to be related to a disorder of calcium homeostasis in the puerperium.

Pavlovian extinction, phobias, and the limits of the cognitive paradigm.

The slow or total lack of decrease in some autonomic responses during extinction in aversive conditioning and concomitant verbalization of fear have remained a problem for learning theories and psychophysiology. Removal of the aversive stimulus should result in a rapid decrement in responding, as it does in cognitive and somatic systems. In laboratory analogues of phobia and clinical neurosis, however, such decreases do not occur in some autonomic responses and reported fear. In this article three areas of research are presented in which dissociations occur between cognitive and autonomic responses: 1) relational learning, 2) phobia, and 3) incubation. The data indicate that there are some important distinctions to be made concerning the properties of different psychological and physiological systems. These distinctions pertain to the differences between cognitive and noncognitive systems, between the two branches of the ANS, and between acquisition and extinction processes. These distinctions lead to a number of hypotheses concerning dissociations between response systems and have important implications for the understanding and treatment of neurosis.

Effects of ethanol on visual evoked responses in monkeys performing a memory task.

The effects of ethanol on behavior and visual evoked potentials were investigated in monkeys performing a visual short-term memory task. Ethanol induced a dose-dependent deficit in performance and a prolongation of visuo-motor reaction time. The normal patterns of ocular motility were concomitantly altered. The potentials elicited in the lateral geniculate nucleus, the striate cortex, the inferotemporal cortex, the amygdala, and the mesencephalic reticular formation by a colored stimulus used by the animal in the task were attenuated by the alcohol in dose-related manner. In contrast, potentials elicited in the striate cortex and reticular formation by a brief and diffuse flash were augmented under the influence of the substance. It is inferred that ethanol can increase the reactivity of reticular and cortical structures to undifferentiated stimuli, while at the same time interfering with the basic mechanisms of visual attention and perception.

Principal component analysis of evoked responses and the effects of alcohol on the geniculo-striate system of the monkey.

This study was designed to test the effects of alcohol on visual evoked potentials in nonhuman primates performing a cognitive task. Flash evoked potentials were recorded from monkeys involved in a delayed matching-to-sample (DMS) paradigm in which the flash served as an alerting signal before each trial. Event-related potentials were recorded from the lateral geniculate nucleus and homolateral striate cortex before, during, and after intravenous administration of saline or ethanol (0.25, 0.5, 1.0, and 2.0 g/kg). Average evoked potentials (AEPs) were computed. Residual waveforms were obtained by subtracting the predrug AEP from postdrug AEPs. A principal component analysis was employed to define the alcohol alterations on the evoked responses. In the analysis each AEP was represented by 40 time points spaced 12 msec apart. These reduced representations of the AEP were entered in the variance-covariance matrix calculations. The first five eigenvectors were computed and plotted. Alcohol produced the greatest variance in the AEPs at the two highest dose levels. So the data were grouped together into three experimental categories: saline, low-dose (0.25-0.5 g/kg) and high-dose (1.0-2.0 g/kg). A correlation template, representing each category, was computed by correlating individual eigenvectors with each sequential average composed of 10 individual evoked potentials in the 200 trials of an experimental session. Alcohol affected the state vector from the brain by loading the correlation coefficient in the opposite direction following alcohol administration in two principal components. One or two of the eigenvectors significantly (P less than 0.01) shifted in geniculate nucleus, indicating that either the nucleus or a previous station was affected by alcohol. In comparison, three or more eigenvectors from striate cortex were shifted significantly following alcohol injection. This difference may be explained by the effect of alcohol on multisynaptic brain structures, including the brain-stem reticular formation, which in turn influenced the cortex.