Behavior Analysts' Relationship to Relating Relations: A Survey on Perceptions, Acceptability, Knowledge, and Capacity for Derived Stimulus Relations Research and Practice

The study and application of procedures that result in stimulus relations via relational frame theory (RFT) and stimulus equivalence (applied as equivalence-based instruction; EBI), have made tremendous strides in contemporary behavior analysis. However, applications at scale lag basic and translational research. We turn our attention inward to investigate potential causes. We replicated and extended Enoch and Nicholson (Behavior Analysis in Practice, 13(3), 609-617, 2020) by conducting a survey of behavior analysts (n = 129) to determine their perceptions, experiences, and barriers in carrying out research and practice based on RFT and EBI. Participants indicated an interest in RFT and EBI, and mostly perceive both within the scope of behavior analysis. A majority of behavior analysts reported formal education in EBI (78.3%), in contrast to a minority in RFT (15.5%). Adoption of procedures derived from RFT and EBI may be in proportion to formal education. Compounded with a lack of accuracy on basic knowledge questions, there is a potential gap in capacity in the field in addressing behavior related to complex verbal behavior.

Embryo blastulation and quality between days 5 and 6 of extended embryo culture

PURPOSE

This study aims to know what proportion of culture day 5 pre-blastocyst-stage embryos develop into blastocysts by culture day 6 and what patient and cycle characteristics are associated with delayed blastocyst formation.

METHODS

A retrospective observational cohort analysis was performed including a total of 9886 embryos from 1008 IVF cycles in 835 patients, who underwent treatment between January 1, 2016, and December 31, 2018. Autologous fresh in vitro fertilization (IVF) cycles at a single academic center were included in the analysis. Embryos were group-cultured using single-step culture media. Blastulation was defined as the presence of a new blastocyst. Usable blastulation was defined as the presence of a new good or excellent quality, expanded, hatching, or hatched blastocysts.

RESULTS

The mean blastulation rate between days 5 and 6 of extended embryo culture was 30.9%. The mean percentage of embryos developing into usable blastocyst-stage embryos was 19.8%. The factors associated with blastulation on day 6 included the total number of embryos and the number of pre-blastocysts on day 5, as well as the use of ICSI. Age, the number of total embryos, those remained in culture and pre-blastocysts, as well as the blastulation rate on day 5 were associated with usable blastulation.

CONCLUSION

It is important to know the usable blastocyst development rate between culture days 5 and 6 in order to adequately counsel patients debating whether to proceed with fresh ET on day 5 or forego ET with the expectation that embryos will be biopsied for PGT and/or cryopreserved on culture day 6. Our findings provide evidence to help guide patients in this difficult decision.

Addressing Cultural Determinants of Health for Latino and Hmong Patients with Limited English Proficiency: Practical Strategies to Reduce Health Disparities

We explored how addressing culture may improve patient-provider relationships and reduce health disparities for racial and ethnic individuals with limited English proficiency (LEP). We analyzed qualitative data collected to explore health disparities in preventive cancer screenings for Hmong and Spanish-speaking LEP patients in a large Midwest healthcare system. We interviewed 20 participants (10 from each group) and the audiotaped interviews were transcribed verbatim, then back translated focusing on meaning. Data was analyzed using content analysis. Two themes are: conversation is relational and quality time is valued. Good communication skills involve the amount of conversation, clear explanations, and engaging with the patient. Quality of time meant physical time spent with patient and the task-oriented nature of the encounter. Cultural literacy in healthcare practice helps to understand the whole patient rather than focusing on the symptoms of illness. Patients should not be treated in isolation of their culture. A patient-centered approach to care means physicians should not remain culturally neutral but be more culturally sensitive. We propose steps to reduce disparities by increasing the awareness of cultural literacy for physicians to improve patient-provider relationship.

Simple tone discriminations are disrupted following experimental frontal traumatic brain injury in rats

PRIMARY OBJECTIVE

To assess cognitive deficits in a rat model of brain injury.

RESEARCH DESIGN

Cognitive deficits are some of the most pervasive and enduring symptoms of frontal traumatic brain injury (TBI) in human patients. In animal models, the assessment of cognitive deficits from TBI has primarily been limited to tests of spatial learning. Recently, simple discrimination performance has been shown to be sensitive to frontal brain damage. The current study provides a detailed characterization of deficits in a two-choice tone discrimination following a bilateral frontal controlled cortical impact injury.

METHODS AND PROCEDURES

Rats were trained on a two-tone discrimination task in a standard operant chamber, then either a frontal brain injury was delivered or sham procedures performed. Following recovery, they were re-tested on the discrimination task and then tested on a reversal of the discrimination.

MAIN OUTCOMES AND RESULTS

Frontal injury caused substantial deficits in responding and discrimination accuracy as well as an increase in side bias.

CONCLUSIONS

Based on the outcomes seen in this study, discrimination and other operant tasks may provide a sensitive tool to assess the effect of therapeutic agents on cognitive deficits in animal models, which could lead to improved characterization of deficits and yield an improved assessment tool to aid in drug discovery.

Deficits in discrimination after experimental frontal brain injury are mediated by motivation and can be improved by nicotinamide administration

One of the largest challenges in experimental neurotrauma work is the development of models relevant to the human condition. This includes both creating similar pathophysiology as well as the generation of relevant behavioral deficits. Recent studies have shown that there is a large potential for the use of discrimination tasks in rats to detect injury-induced deficits. The literature on discrimination and TBI is still limited, however. The current study investigated motivational and motor factors that could potentially contribute to deficits in discrimination. In addition, the efficacy of a neuroprotective agent, nicotinamide, was assessed. Rats were trained on a discrimination task and motivation task, given a bilateral frontal controlled cortical impact TBI (+3.0 AP, 0.0 ML from bregma), and then reassessed. They were also assessed on motor ability and Morris water maze (MWM) performance. Experiment 1 showed that TBI resulted in large deficits in discrimination and motivation. No deficits were observed on gross motor measures; however, the vehicle group showed impairments in fine motor control. Both injured groups were impaired on the reference memory MWM, but only nicotinamide-treated rats were impaired on the working memory MWM. Nicotinamide administration improved performance on discrimination and motivation measures. Experiment 2 evaluated retraining on the discrimination task and suggested that motivation may be a large factor underlying discrimination deficits. Retrained rats improved considerably on the discrimination task. The tasks evaluated in this study demonstrate robust deficits and may improve the detection of pharmaceutical effects by being very sensitive to pervasive cognitive deficits that occur after frontal TBI.

Magnitude effects for experienced rewards at short delays in the escalating interest task

A first-person shooter video game was adapted for the study of choice between smaller sooner and larger later rewards. Participants chose when to fire a weapon that increased in damage potential over a short interval. When the delay to maximum damage was shorter (5-8 s), people showed greater sensitivity to the consequences of their choices than when the delay was longer (17-20 s). Participants also evidenced a magnitude effect by waiting proportionally longer when the damage magnitudes were doubled for all rewards. The experiment replicated the standard magnitude effect with this new video game preparation over time scales similar to those typically used in nonhuman animal studies and without complications due to satiation or cost.

Sensitivity to changing contingencies in an impulsivity task

Using a video-game-based escalating interest task, participants repeatedly encountered a reward that gradually increased in value over a 10-second interval. Responding early in the interval netted less immediate reward than responding later in the interval. Each participant experienced four different reward contingencies for waiting. These contingencies were changed three times as the experiment proceeded. Behavior tracked these changing contingencies, but wait times reflected long-term carryover from the previously assigned contingencies. Both the tendency to respond slowly and the optimality of behavior were affected by the order of contingencies experienced. Demographic variables only weakly predicted behavior, and delay discounting rate in a hypothetical money choice task predicted choice only when the contingencies in the game were weaker.

Rapid acquisition of bias in signal detection: dynamics of effective reinforcement allocation

We investigated changes in bias (preference for one response alternative) in signal detection when relative reinforcer frequency for correct responses varied across sessions. In Experiment 1, 4 rats responded in a two-stimulus, two-response identification procedure employing temporal stimuli (short vs. long houselight presentations). Relative reinforcer frequency varied according to a 31-step pseudorandom binary sequence and stimulus duration difference varied over two values across conditions. In Experiment 2, 3 rats responded in a five-stimulus, two-response classification procedure employing temporal stimuli. Relative reinforcer frequency was varied according to a 36-step pseudorandom ternary sequence. Results of both experiments were analyzed according to a behavioral model of detection. The model was extended to incorporate the effects of current and previous session reinforcer frequency ratios on current-session performance. Similar to findings with concurrent schedules, effects on bias of relative reinforcer frequency were highest for the current session. However, carryover from reinforcer ratios of previous sessions was evident. Generally, the results indicate that bias can come under control of frequent changes in relative reinforcer frequency in both identification and classification procedures.

Deciding when to "cash in" when outcomes are continuously improving: an escalating interest task

A first-person shooter video game was adapted for the study of choice between smaller sooner and larger later outcomes. Participants chose when to fire a weapon that increased in damage potential over a 10s interval, an escalating interest situation. Across two experiments, participants demonstrated sensitivity to the nature of the mathematical function that defined the relationship between waiting and damage potential. In Experiment 1, people tended to wait longer when doing so allowed them to eliminate targets more quickly. In Experiment 2, people tended to wait longer to increase the probability of a constant magnitude outcome than to increase the magnitude of a 100% certain outcome that was matched for the same expected value (i.e., probability times magnitude). The two experiments demonstrated sensitivity to the way in which an outcome improves when the outcome is continuously available. The results also demonstrate that this new video game task is useful for generating sensitivity to delay to reinforcement over time scales that are typically used in nonhuman animal studies.

Altered states: the impact of immediate craving on the valuation of current and future opioids

Based on prior research showing that people underestimate the influence of motivational states they are not currently experiencing, we predicted and found that heroin addicts would value an extra dose of the heroin substitute Buprenorphine more highly when they were currently craving (right before receiving BUP) than when they were currently satiated (right after receiving BUP) -- even when the extra BUP was to be received 5 days later. If addicts cannot appreciate the intensity of craving when they are not currently experiencing it, as these results suggest, it seems unlikely that those who have never experienced craving could predict its motivational force. Under-appreciation of craving by non-addicts may contribute to initial decisions to experiment with drugs.

Contextual control of delay discounting by pathological gamblers

The present study demonstrated the relative impact of gambling and nongambling contexts on the degree of delay discounting by pathological gamblers. We used a delay-discounting task with 20 pathological gamblers in and out of the natural context in which they regularly gambled. For 16 of the 20 participants, it appeared that the difference of context altered the subjective value of delayed rewards, thereby producing relative changes in delay-discounting rates that were generally consistent with a hyperbolic model of intertemporal choice. The current data suggest that empirically derived k values from delay-discounting tasks are context sensitive and are not constant across various settings for the individual. Implications for future transitional research on addictive disorders generally, and gambling specifically, are discussed.

Buprenorphine treatment for opioid dependence: the relative efficacy of daily, twice and thrice weekly dosing

This randomized clinical trial evaluated the relative efficacy of three buprenorphine dosing schedules. Opioid-dependent adults were randomly assigned to receive buprenorphine seven, 3 or 2 days per week for 24 weeks. Daily maintenance doses were 4, 8, 10, or 12 mg of the sublingual buprenorphine solution. Participants who attended the clinic daily received a maintenance dose of buprenorphine daily. Participants who attended the clinic thrice weekly received double their maintenance dose on Monday and Wednesday, followed by a triple dose on Friday. Participants who attended the clinic twice weekly received quadruple their maintenance dose of buprenorphine on Monday and triple their maintenance dose on Friday. Results demonstrated that all dosing regimens were of comparable efficacy in promoting treatment retention, opioid and cocaine abstinence, and reductions in HIV risk behavior (especially as related to drug use) and severity of life problems. Predictor analyses identified sub-populations of opioid-dependent individuals that may have a more positive treatment outcome under each buprenorphine dosing condition. Less-than-daily dosing schedules may provide the opportunity for treatment programs to serve a greater number of opioid-dependent patients and reduce the risk of medication diversion, which may, in turn, have a positive impact on community support of science-based treatment for opioid-dependence.

Delay discounting by pathological gamblers

Discounting of delayed rewards by pathological gamblers was compared to discounting of delayed rewards by matched control nongambling participants. All participants completed a hypothetical choice task in which they made repeated choices between dollars 1,000 available after a delay and an equal or lesser amount of money available immediately. The delay to the large amount of money was varied from 1 week to 10 years across conditions. Indifference points between immediate money and delayed money were identified at each delay condition by varying the amount of immediate money across choice trials. For the majority of participants, indifference points decreased monotonically across delays. Overall, gamblers discounted the delayed rewards more steeply than did control participants.

Mild opioid deprivation increases the degree that opioid-dependent outpatients discount delayed heroin and money

RATIONALE

A growing literature suggests that excessive temporal discounting of delayed rewards may be a contributing factor in the etiology of substance abuse problems. Little is known, however, about how drug deprivation may affect temporal discounting of delayed rewards by drug-dependent individuals.

OBJECTIVE

To examine the extent to which opioid deprivation affects how opioid-dependent individuals discount small, medium and large quantities of delayed heroin and money.

METHODS

Thirteen opioid-dependent individuals maintained on buprenorphine completed a hypothetical choice task in which they choose between a constant delayed reward amount and an immediate reward amount that was adjusted until they expressed indifference between both outcomes. The task was completed for three values of heroin and money rewards during eight sessions under conditions of opioid deprivation (four sessions) and satiation (four sessions).

RESULTS

Across conditions, hyperbolic functions provided a good fit for the discounting data. Degree of discounting was significantly higher when subjects were opioid deprived. Consistent with previous findings, degree of discounting was higher for heroin than money and inversely related to the magnitude of the reward.

CONCLUSION

Opioid deprivation increased the degree to which dependent individuals discounted delayed heroin and money. Understanding the conditions that affect how drug-dependent individuals discount delayed rewards might help us understand the myopic choices made by such individuals and help improve treatment outcomes.

Limits to buprenorphine dosing: a comparison between quintuple and sextuple the maintenance dose every 5 days

The relative efficacy of quintuple and sextuple buprenorphine dosing in abating withdrawal symptoms for 120 h was compared in opioid-dependent outpatients. Fourteen subjects received buprenorphine in a double-blind, placebo-controlled, cross-over design. Daily sublingual maintenance doses were 4 mg/70 kg (n=4) and 8 mg/70 kg (n=10). After a stabilization period of daily maintenance administration, subjects received quintuple (5x daily maintenance dose) and sextuple (6x daily maintenance dose) doses every 120 h. Measures of opioid agonist and withdrawal effects were assessed daily. Subjective ratings of withdrawal were significantly greater than baseline ratings beyond 96-h post dosing under both regimens. There was no evidence, however, that those subjective ratings of withdrawal differed between the two regimens. Thus, these data suggest that sextuple buprenorphine dosing, administered every 5 days, does not abate opioid-withdrawal beyond 96 hours.

Impact of interpreter services on delivery of health care to limited-English-proficient patients

OBJECTIVE

To determine whether professional interpreter services increase the delivery of health care to limited-English-proficient patients.

DESIGN

Two-year retrospective cohort study during which professional interpreter services for Portuguese and Spanish-speaking patients were instituted between years one and two. Preventive and clinical service information was extracted from computerized medical records.

SETTING

A large HMO in New England.

PARTICIPANTS

A total of 4,380 adults continuously enrolled in a staff model health maintenance organization for the two years of the study, who either used the comprehensive interpreter services (interpreter service group [ISG]; N = 327) or were randomly selected into a 10% comparison group of all other eligible adults (comparison group [CG]; N = 4,053).

MEASUREMENTS AND MAIN RESULTS

The measures were change in receipt of clinical services and preventive service use. Clinical service use and receipt of preventive services increased in both groups from year one to year two. Clinical service use increased significantly in the ISG compared to the CG for office visits (1.80 vs. 0.70; P <.01), prescriptions written (1.76 vs 0.53; P <.01), and prescriptions filled (2.33 vs. 0.86; P<.01). Rectal examinations increased significantly more in the ISG compared to the CG (0.26 vs. 0.02; P =.05) and disparities in rates of fecal occult blood testing, rectal exams, and flu immunization between Portuguese and Spanish-speaking patients and a comparison group were significantly reduced after the implementation of professional interpreter services.

CONCLUSION

Professional interpreter services can increase delivery of health care to limited-English-speaking patients.

Language barriers to informed consent and confidentiality: the impact on women's health

Obtaining informed consent and maintaining confidentiality are critical to the way we practice medicine and remain a crucial part of our medicolegal responsibility to the patient and to society. Nevertheless, little attention has been paid to these topics in populations who may have limited English proficiency. Despite research suggesting that language barriers have direct effects on health and health care delivery, many health care settings do not provide professionally trained interpreters to patients who need them. This is clearly a challenge that will only grow as our nation becomes more diverse. Perhaps nowhere is this issue more significant than in women's health, given the very personal and sensitive nature of the medical exams and interventions. As health care providers, we must conduct and facilitate research on how language barriers compromise quality of care, and we must advocate for systems and policy change.

Receipt of cancer screening procedures among Hispanic and non-Hispanic health maintenance organization members

BACKGROUND

Hispanic Americans have been shown to receive fewer cancer screening procedures than nonminority populations. Although lack of insurance or a regular source of care appear to be important determinants, cultural factors also have been suggested. This study examines whether Hispanic patients receive cancer screening at the same rate as the non-Hispanic population when both groups have equivalent insurance and a regular source of care.

METHODS

Receipt of five cancer screening procedures (mammography, Pap test, fecal occult blood testing, breast examination, and rectal examination) was determined for adult health maintenance organization (HMO) members who met appropriate age and gender criteria. Rates of receipt were compared for 2 cohorts over a 2-year period: Hispanic members identified by surname and a comparison group, a 10% random sample of the non-Spanish surnamed members. Only members with at least one HMO contact over the study period were included. Logistic regression was used to test whether being in the Hispanic group was associated with decreased likelihood of receiving the procedure at least once over the 2 years, adjusting for potential confounders.

RESULTS

Among the comparison group, a high proportion received each recommended procedure at least once (0.70-0.86). The proportions were very similar for the Hispanic group (0.67-0.84). None of the rates differed statistically for the two groups.

CONCLUSIONS

Hispanic HMO members received cancer screening at the same high rate as non-Hispanics, suggesting that insurance coverage and continuity of care are more important than cultural factors in determining rates of cancer screening receipt.

Human performance on negative slope schedules of points exchangeable for money: a failure of molar maximization

Panel pressing was generated and maintained in 5 adult humans by schedules of points exchangeable for money. Following exposure to a variable-interval 30-s schedule and to a linear variable-interval 30-s schedule (which permitted points to accumulate in an unseen "store" in the absence of responding), subjects were exposed to a series of conditions with a point-subtraction contingency arranged conjointly with the linear variable-interval schedule. Specifically, points were added to the store according to the linear-variable interval 30-s schedule and were subtracted from the store according to a ratio schedule. Ratio value varied across conditions and was determined individually for each subject such that the subtraction contingency would result in an approximately 50% reduction in the rate of point delivery. Conditions that included the subtraction contingency were termed negative slope schedules because the feedback functions were negatively sloped across all response rates greater than the inverse of the variable-interval schedule, in this case, two per minute. Overall response rates varied inversely with the subtraction ratio, indicating sensitivity to the negative slope conditions, but were in excess of that required by accounts based on strict maximization of overall reinforcement rate. Performance was also not well described by a matching-based account. Detailed analyses of response patterning revealed a consistent two-state pattern in which bursts of high-rate responding alternated with periods of prolonged pausing, perhaps reflecting the joint influence of local and overall reinforcement rates.

Modeling drug consumption in the clinic using simulation procedures: demand for heroin and cigarettes in opioid-dependent outpatients

Use of a time- and cost-efficient simulation procedure to assess reinforcement efficacy in humans was explored in the present study. Opioid-dependent outpatients completed questionnaires asking how many cigarettes or bags of heroin they would purchase across a range of prices. Reported consumption patterns conformed to a quantitative model that has been successful in accounting for data obtained in studies using real rather than hypothetical consequences, suggesting the self-report data may have been a valid proxy for observations of actual consumption patterns. Simulation procedures may thus be a useful supplement to traditional operant methods for the assessment of reinforcement efficacy in humans, particularly in situations where the use of operant methods is logistically difficult or ethically questionable. The relationship between behavioral-economic and traditional measures of reinforcement efficacy is also discussed.

Three predictions of the economic concept of unit price in a choice context

Economic theory makes three predictions about consumption and response output in a choice situation: (a) When plotted on logarithmic coordinates, total consumption (i.e., summed across concurrent sources of reinforcement) should be a positively decelerating function, and total response output should be a bitonic function of unit price increases; (b) total consumption and response output should be determined by the value of the unit price ratio, independent of its cost and benefit components; and (c) when a reinforcer is available at the same unit price across all sources of reinforcement, consumption should be equal between these sources. These predictions were assessed in human cigarette smokers who earned cigarette puffs in a two-choice situation at a range of unit prices. In some sessions, smokers chose between different amounts of puffs, both available at identical unit prices. Individual subjects' data supported the first two predictions but failed to support the third. Instead, at low unit prices, the relatively larger reinforcer (and larger response requirement) was preferred, whereas at high unit prices, the smaller reinforcer (and smaller response requirement) was preferred. An expansion of unit price is proposed in which handling costs and the discounted value of reinforcers available according to ratio schedules are incorporated.

Modeling drug consumption in the clinic using simulation procedures: demand for heroin and cigarettes in opioid-dependent outpatients

Use of a time- and cost-efficient simulation procedure to assess reinforcement efficacy in humans was explored in the present study. Opioid-dependent outpatients completed questionnaires asking how many cigarettes or bags of heroin they would purchase across a range of prices. Reported consumption patterns conformed to a quantitative model that has been successful in accounting for data obtained in studies using real rather than hypothetical consequences, suggesting the self-report data may have been a valid proxy for observations of actual consumption patterns. Simulation procedures may thus be a useful supplement to traditional operant methods for the assessment of reinforcement efficacy in humans, particularly in situations where the use of operant methods is logistically difficult or ethically questionable. The relationship between behavioral-economic and traditional measures of reinforcement efficacy is also discussed.

Discounting of delayed rewards in opioid-dependent outpatients: exponential or hyperbolic discounting functions?

Recent theories of substance abuse have used value discounting of delayed rewards to partly explain the decision to take drugs. Normative-economic theory holds that an exponential function describes the effects of delay on discounting, whereas the matching law posits a hyperbolic discounting function. The ability of these functions to describe 18 human heroin-dependent individuals' monetary- and heroin-reward delay-discounting functions was assessed. In the 1st condition, participants chose between immediate and delayed hypothetical monetary rewards. Delayed rewards were $1,000, and the immediate reward amount was adjusted until choices reflected indifference. In the 2nd condition, participants chose between immediate and delayed heroin (the delayed amount was that which each participant reported he or she could purchase with $1,000). The hyperbolic function produced significantly higher R2 values and significantly lower sums of squared error values. Consistent with previous findings, delayed heroin rewards were discounted at a significantly higher rate than were delayed monetary rewards.

Discounting of delayed rewards in opioid-dependent outpatients: exponential or hyperbolic discounting functions?

Recent theories of substance abuse have used value discounting of delayed rewards to partly explain the decision to take drugs. Normative-economic theory holds that an exponential function describes the effects of delay on discounting, whereas the matching law posits a hyperbolic discounting function. The ability of these functions to describe 18 human heroin-dependent individuals' monetary- and heroin-reward delay-discounting functions was assessed. In the 1st condition, participants chose between immediate and delayed hypothetical monetary rewards. Delayed rewards were $1,000, and the immediate reward amount was adjusted until choices reflected indifference. In the 2nd condition, participants chose between immediate and delayed heroin (the delayed amount was that which each participant reported he or she could purchase with $1,000). The hyperbolic function produced significantly higher R2 values and significantly lower sums of squared error values. Consistent with previous findings, delayed heroin rewards were discounted at a significantly higher rate than were delayed monetary rewards.

Signs of emotional disturbance three years after early hospitalization

Tested by a retrospective study the hypothesis that children in the 6-36 months age range in case of lengthy (> 3 days) or repeated (more than once) hospitalization are susceptible to persistent emotional disturbances. Families of children with such a "risky" hospitalization history were approached by mail, several years (M = 36 months, SD = 10) after the latest discharge. The parents of these children (N = 40; mean age 59 months) and of a control group without a risky hospitalization history (N = 73; mean age 58 months) reported about current problem behavior of their child. Scores on the Behaviour Checklist (Richman et al., 1982) were significantly (p < .05) elevated in the sample. Specific signs were poor concentration, immoderate attention seeking, deficits of bowel control, and fearfulness. Cases of surgery significantly exceeded others in signs of disturbance. Although the protective value of parental attendance could not be demonstrated in this study, on the basis of prior research, rooming-in is recommended as a necessary precaution in the 6-36 months age range.

Effects of culture on back pain in Australian aboriginals

STUDY DESIGN

A cross-sectional survey was conducted.

OBJECTIVES

To describe the occurrence of back pain and associated behaviors and disabilities in a semitraditional Australian aboriginal community.

SUMMARY OF BACKGROUND DATA

There are few studies of back pain in isolated and nonindustrial societies.

METHODS

The authors lived with, observed, and interviewed most adult members of a small aboriginal community and placed information about spinal pain in context of aboriginal beliefs and practices.

RESULTS

Nearly half the adults in this community experienced long-term private spinal pain, but because of their cultural beliefs, did not commonly make this pain public.

CONCLUSIONS

Cultural beliefs and practices influence how people respond to back pain in themselves and in others, including how and whether they present to health professionals or seek involvement of others.

Humans' choices in situations of time-based diminishing returns: effects of fixed-interval duration and progressive-interval step size

Four adult humans made repeated choices between two time-based schedules of points exchangeable for money: a fixed-interval schedule and a progressive-interval schedule that began at 0 s and increased in fixed increments following each point delivered by that schedule. Under reset conditions, selection of the fixed schedule not only produced a point but also reset the progressive interval to 0 s. Reset conditions alternated with no-reset conditions, in which the progressive-interval duration was independent of fixed-interval choices. Fixed-interval duration and progressive-interval step size were varied independently across conditions. Subjects were exposed to all step sizes in ascending order at a given fixed-interval value before the value was changed. Switching from the progressive-interval schedule to the fixed-interval schedule was systematically related to fixed-interval duration, particularly under no-reset conditions. Switching occurred more frequently and earlier in the progressive-schedule sequence under reset conditions than under no-reset conditions. Overall, the switching patterns conformed closely to predictions of an optimization account based upon maximization of overall reinforcement density, and did not appear to depend on schedule-controlled response patterns or on verbal descriptions of the contingencies.

Suppression of human granulocyte-macrophage colony formation in vitro by natural killer cells

This study has demonstrated the ability of human bone marrow natural killer (NK) cells to inhibit the formation of granulocyte-macrophage colonies from autologous bone marrow derived committed progenitors in vitro. NK cell activity was demonstrated in all marrow samples and could be significantly increased by pretreatment of the bone marrow mononuclear cells with IFN-alpha. Bone marrow preincubated with IFN-alpha produced significantly fewer colonies in both Day 7 and Day 14 colony assays compared with untreated marrow. Removal of active NK cells by Leu 11b and complement significantly increased the number of colonies observed in both Day 7 and Day 14 assays, but this was not the case when NK cell-depleted marrow was treated with IFN-alpha prior to the GM assays. These results have further shown that NK cells and IFN-alpha are involved in regulating granulopoiesis by demonstrating that IFN-alpha can inhibit granulocyte/macrophage colonies in the presence or absence of NK cells in the bone marrow.

The role of polysomnography in the differential diagnosis of chronic insomnia

The authors examined the accuracy of the differential diagnosis of chronic insomnia with and without sleep laboratory studies in a consecutive series of 123 patients. All patients were evaluated by means of a sleep/wake log, a sleep habits questionnaire, structured psychiatric and clinical interviews, and a minimum of two consecutive nights of polysomnography. Notwithstanding a high rate of Research Diagnostic Criteria (RDC)-diagnosed psychopathology (63%) in this sample, the major finding was that in 49% of the patients laboratory results added to, refuted, and/or failed to support the clinical impression. This resulted in substantial modification of the initial diagnostic formulation and therefore in increased specificity of diagnosis.

Recognizing the adolescent drug abuser

Adolescents are at high risk for using and abusing illicit drugs. Guidelines for recognizing drug abusers are presented as well as a staging process for progression of drug use. The family physician is in an ideal position to identify young users/abusers and to assist them and their families in obtaining much needed assistance.

Defective in vitro immunoglobulin production in response to pokeweed mitogen in patients with Hodgkin's disease pretreatment and in remission

In vitro production of IgG and IgM from peripheral blood lymphocytes and B-cell enriched fractions was assessed in a group of Hodgkin's disease (HD) patients and normal controls using pokeweed mitogen (PWM) stimulation. Our studies demonstrated a significant (P less than 0.01) reduction in the absolute number of helper (OKT4 positive) T cells and a significant alteration in the helper/suppressor T-cell ratio (0.89 +/- 0.15) compared to normal (1.83 +/- 0.31). Results from PWM stimulation experiments demonstrated that HD patients produced significantly lower IgG (P less than 0.01) and IgM (P less than 0.01) levels than controls. Synthesis of IgM but not IgG induced by PWM was subnormal after addition to patient B-cell cultures of autologous irradiated T cells or allogeneic irradiated normal T lymphocytes. Irradiated T cells from HD patients were as effective as normal T cells in helping PWM induced IgG and IgM synthesis by normal B cells. Our results suggest that in HD impaired circulating B-cell function is partly due to T-suppressor cell activity and furthermore that B-cell subpopulations producing different immunoglobulin isotypes may either be defective or vary in their susceptibility to T-cell suppression.

Changes in the permeability of the blood-brain barrier under hyperbaric conditions

Hyperbaric oxygen therapy (HBO) has been used in the treatment of cerebral edema with variable results. Two different actions of HBO, one decreasing and the other increasing cerebral edema, have been postulated. We examined the permeability of the blood-brain barrier (BBB) in rats and cats. Animals of each species were treated for 90 min/d with 100% oxygen at a pressure of 2.5 atm for 5 consecutive days. Following treatment, cadmium-free ferritin was injected intravenously. Sections of the brain were prepared for electron microscopic evaluation of the capillaries and their neighboring structures. Perivascular edematous zones were observed. Ferritin particles penetrated through the capillary endothelium and into the pericapillary structures. Hyperbaric oxygenation appears to increase the permeability of cerebral vessel walls in normal animals. Further work on this phenomenon may provide a more rational basis for the treatment of cerebral edema with HBO.