Disaggregating within- and between-person effects of affect on drinking behavior in a clinical sample with alcohol use disorder

OBJECTIVE

The goal of the current study was to better understand affect-drinking relations among those diagnosed with an alcohol use disorder (AUD), as recent meta-analytic work suggests that daily negative affect may not universally predict subsequent alcohol consumption in those nondependent on alcohol. Specifically, we investigated the between- and within-person effects of positive and negative affects on drinking.

METHOD

Participants (n = 92) who met AUD diagnostic criteria completed a 90-day daily assessment of drinking behavior and positive and negative affects.

RESULTS

Time-lagged multilevel modeling revealed that within-person elevations in negative affect predicted increased odds and quantity of drinking later in the day. Relations between positive affect and drinking were nonsignificant.

CONCLUSIONS

These findings are in contrast to recent meta-analytic findings and highlight the complexity of affect-drinking relations among those diagnosed with AUD. (PsycInfo Database Record (c) 2023 APA, all rights reserved).

Reductions in Drinking Predict Increased Distress: Between- and Within-Person Associations between Alcohol Use and Psychological Distress During and Following Treatment

BACKGROUND

As the nature of the association between alcohol use disorder (AUD) and other disorders is not well understood, the ways in which psychological distress changes during the course of treatment for AUD are relatively unknown. Existing literatures posit 2 competing hypotheses such that treatment for AUD concurrently decreases alcohol use and psychological distress or treatment for AUD decreases alcohol use and increases psychological distress. The current study examined the ways in which psychological distress changed as a function of treatment for AUD, including the relationship between psychological distress and drinking behaviors.

METHODS

Secondary data analysis was conducted on an existing clinical trial dataset that investigated the effect of cognitive-behavioral therapy and therapeutic alliance feedback on AUDs. Specifically, data collected at baseline, posttreatment, 3-month, 6-month, 9-month, and 12-month follow-up assessments were examined.

RESULTS

Results indicated decreases in heavy drinking days, increases in percentage of days abstinent, and decreases in overall psychological distress. Findings also revealed that changes in psychological distress did not predict changes in drinking at the next time interval; however, decreases in drinking predicted higher psychological distress at the next assessment. Further, average levels of psychological distress were positively associated with rates of drinking.

CONCLUSIONS

The current study provides some insight into how psychological distress changes during the course of treatment for AUD, including the relationship between changes in drinking and such symptoms. Future research should continue to explore these relationships, including the ways in which treatment efforts can address what may be seen as paradoxical effects.

Impact of Pretreatment Change on Mechanism of Behavior Change Research: An Applied Example Using Alcohol Abstinence Self-Efficacy

OBJECTIVE

With the growing recognition that, for some, significant changes in drinking occur before the first treatment session (i.e., pretreatment change), researchers have called for the careful assessment of when change occurs and its potential impact on mechanism of behavior change (MOBC) research. Using a commonly hypothesized MOBC variable, alcohol abstinence self-efficacy, the primary aim of this study was to examine the effect of pretreatment change on the study of MOBCs.

METHOD

Sixty-three individuals diagnosed with alcohol dependence were recruited to participate in a 12-week cognitive-behavioral treatment. Participants completed weekly assessments of self-efficacy and drinking behaviors.

RESULTS

Multilevel time-lagged regression models indicated that pretreatment change significantly moderated the effect of self-efficacy on the number of drinking days, such that among those higher on pretreatment change, higher self-efficacy ratings predicted lower rates of drinking days in the week until the next treatment session. In contrast, pretreatment change did not moderate the effect of self-efficacy on the rate of heavy drinking days.

CONCLUSIONS

Results from the current study add to a small but growing body of research highlighting the importance of pretreatment change when studying MOBCs. Further, these results provide important insights into the conditions in which self-efficacy may play an important role in treatment outcomes.

Health-related internet use among opioid treatment patients

The Internet and smartphones have become commonplace and can be effective in overcoming traditional barriers to accessing health information about substance use disorders (SUD), and their prevention or treatment. Little is known, however, about specific factors that may influence the use of these technologies among socioeconomically disadvantaged populations with SUDs. This study characterized the use of digital technologies and the Internet among individuals receiving treatment for opioid use disorder, focusing on identifying predictors of Internet use for health-related purposes. Participants came from an urban opioid replacement therapy program and completed a face-to-face survey on Internet and technology use. We examined the association between online health information seeking and technology acceptance variables, including perceived usefulness, effort expectancy, social influence, and facilitating conditions (e.g., availability of devices/services and technical support). Participants (N = 178, ages 18–64) endorsed high rates of current smartphone ownership (94%) and everyday Internet use (67%). 88% of participants reported searching online for information about health or medical topics in the past 3 months. Predictors of Internet use for health-related purposes were higher technology acceptance for mobile Internet use, younger age, current employment, and less bodily pain. Our results demonstrate high acceptance and use of mobile technology and the Internet among this sample of socioeconomically disadvantaged individuals with SUDs. However, these findings also highlight the importance of identifying barriers that disadvantaged groups face in using mobile technologies when designing technology-based interventions for this population.

•

94% of those surveyed with an opioid use disorder owned a smartphone.

•

67% used the Internet everyday, and 88% searched the Internet for health information.

•

Technology acceptance and bodily pain predicted online health information seeking.

Development and Psychometric Evaluation of a Brief Approach and Avoidance of Alcohol Questionnaire

BACKGROUND

The Approach and Avoidance of Alcohol Questionnaire (AAAQ) was developed as a measure of craving to assess both desires to consume and desires to avoid consuming alcohol. Although the measure has been used in a variety of populations to predict future alcohol use behavior, the factor structures observed vary based on sample type (e.g., clinical vs. college samples) and may be overly long for use in repeated measures designs. The current article describes the development of a brief version of the AAAQ for use in clinical populations.

METHODS

Using existing data sets of individuals in treatment for alcohol use disorder, exploratory analyses (e.g., exploratory factor analysis and item response theory) were conducted using an inpatient sample (N = 298) at a substance abuse treatment facility. Confirmatory analyses (e.g., confirmatory factor analysis and multiple regression) were conducted using an inpatient detoxification sample (N = 175) and a longitudinal outpatient treatment sample (N = 53).

RESULTS

The brief AAAQ had comparable internal consistency, explained a similar amount of variance in alcohol consumption and related problems, and exhibited superior model fit as compared to the original measure.

CONCLUSIONS

These findings indicate that the brief AAAQ is an effective tool to assess alcohol craving in clinical populations in treatment settings.

Evidence-Based Medicine as a Tool for Undergraduate Probability and Statistics Education

Most students have difficulty reasoning about chance events, and misconceptions regarding probability can persist or even strengthen following traditional instruction. Many biostatistics classes sidestep this problem by prioritizing exploratory data analysis over probability. However, probability itself, in addition to statistics, is essential both to the biology curriculum and to informed decision making in daily life. One area in which probability is particularly important is medicine. Given the preponderance of pre health students, in addition to more general interest in medicine, we capitalized on students' intrinsic motivation in this area to teach both probability and statistics. We use the randomized controlled trial as the centerpiece of the course, because it exemplifies the most salient features of the scientific method, and the application of critical thinking to medicine. The other two pillars of the course are biomedical applications of Bayes' theorem and science and society content. Backward design from these three overarching aims was used to select appropriate probability and statistics content, with a focus on eliciting and countering previously documented misconceptions in their medical context. Pretest/posttest assessments using the Quantitative Reasoning Quotient and Attitudes Toward Statistics instruments are positive, bucking several negative trends previously reported in statistics education.

Visualizing Network Traffic to Understand the Performance of Massively Parallel Simulations

The performance of massively parallel applications is often heavily impacted by the cost of communication among compute nodes. However, determining how to best use the network is a formidable task, made challenging by the ever increasing size and complexity of modern supercomputers. This paper applies visualization techniques to aid parallel application developers in understanding the network activity by enabling a detailed exploration of the flow of packets through the hardware interconnect. In order to visualize this large and complex data, we employ two linked views of the hardware network. The first is a 2D view, that represents the network structure as one of several simplified planar projections. This view is designed to allow a user to easily identify trends and patterns in the network traffic. The second is a 3D view that augments the 2D view by preserving the physical network topology and providing a context that is familiar to the application developers. Using the massively parallel multi-physics code pF3D as a case study, we demonstrate that our tool provides valuable insight that we use to explain and optimize pF3D's performance on an IBM Blue Gene/P system.

Evaluation of the Accuracy of a Triaxial Accelerometer Embedded into a Cell Phone Platform for Measuring Physical Activity

BACKGROUND

Physical activity is important in health and weight management. Several cell phone platforms integrate an accelerometer onto the motherboard. Here we tested the validity of the cell phone accelerometer to assess physical activity in a controlled laboratory setting.

METHODS

31 subjects wore the cell phone on their waist along with the validated Physical Activity Monitoring System (PAMS) with different body postures and during graded walking. Energy expenditure was measured using indirect calorimetry. 11 subjects also wore the iPhone at different locations such as arm, hand, pant pocket, etc.

RESULTS

The cell phone accelerometer was accurate and precise compared to the PAMS, with an intra-class correlation coefficient (r²> 0.98). The cell phone accelerometer showed excellent sequential increases with increased in walking velocity and energy expenditure (r²>0.9).

CONCLUSION

An accelerometer embedded into a cell phone was accurate and reliable in measuring and quantifying physical activity in the laboratory setting. Data from free-living users shows promise for deployment of a comprehensive integrated physical activity promoting and weight loss platform using such mobile technologies.

Central neural and endocrine mechanisms of non-exercise activity thermogenesis and their potential impact on obesity

The rise in obesity is associated with a decline in the amount of physical activity in which people engage. The energy expended through everyday non-exercise activity, called non-exercise activity thermogenesis (NEAT), has a considerable potential impact on energy balance and weight gain. Comparatively little attention has been paid to the central mechanisms of energy expenditure and how decreases in NEAT might contribute to obesity. In this review, we first examine the sensory and endocrine mechanisms through which energy availability and energy balance are detected that may influence NEAT. Second, we describe the neural pathways that integrate these signals. Lastly, we consider the effector mechanisms that modulate NEAT through the alteration of activity levels as well as through changes in the energy efficiency of movement. Systems that regulate NEAT according to energy balance may be linked to neural circuits that modulate sleep, addiction and the stress response. The neural and endocrine systems that control NEAT are potential targets for the treatment of obesity.

Gait and balance of transfemoral amputees using passive mechanical and microprocessor-controlled prosthetic knees

BACKGROUND

Microprocessor-controlled knee joints appeared on the market a decade ago. These joints are more sophisticated and more expensive than mechanical ones. The literature is contradictory regarding changes in gait and balance when using these sophisticated devices.

METHODS

This study employed a crossover design to assess the comparative performance of a passive mechanical knee prosthesis compared to a microprocessor-controlled knee joint in 15 subjects with an above-knee amputation. Objective measurements of gait and balance were obtained.

RESULTS

Subjects demonstrated significantly improved gait characteristics after receiving the microprocessor-controlled prosthetic knee joint (p<0.01). Improvements in gait were a transition from a hyperextended knee to a flexed knee during loading response which resulted in a change from an internal knee flexor moment to a knee extensor moment. The participants' balance also improved (p<0.01). All conditions of the Sensory Organization Test (SOT) demonstrated improvements in equilibrium score. The composite score also increased.

CONCLUSIONS

Transfemoral amputees using a microprocessor-controlled knee have significant improvements in gait and balance.

Nonexercise activity thermogenesis--liberating the life-force

Obesity occurs when energy intake exceeds energy expenditure over a protracted period of time. The energy expenditure associated with everyday activity is called NEAT (Nonexercise activity thermogenesis). NEAT varies between two people of similar size by 2000 kcal day(-1) because of people's different occupations and leisure-time activities. Data support the central hypothesis that NEAT is pivotal in the regulation of human energy expenditure and body weight regulation and that NEAT is important for understanding the cause and effective treatment for obesity.

Feasibility of a walking workstation to increase daily walking

OBJECTIVE

The number of calories expended in the workplace has declined significantly in the past 75 years. A walking workstation that allows workers to walk while they work has the potential to increase caloric expenditure. We evaluated whether employees can and will use walking workstations while performing their jobs.

METHODS AND PROCEDURES

We studied nurses, clinical assistants, secretaries and appointment secretaries using the StepWatch Activity Monitor System (which accurately measures steps taken at slow speeds) while performing their job functions in their usual fashion and while using the walking workstation.

RESULTS

Subjects increased the number of steps taken during the workday by 2000 steps per day (p<0.05). This was equivalent to an increase in caloric expenditure of 100 kcal/day. Subjects reported that they enjoyed using the workstation, that it could be used in the actual work arena and that, if available, they would use it.

DISCUSSION

Walking workstations have the potential for promoting physical activity and facilitating weight loss. Several subjects in this study expended more than 200 extra calories daily using such a system. Further trials are indicated.

International survey of seat belt use exemptions

BACKGROUND

Substantial evidence of seatbelt efficacy has been shown by several studies, and it is widely recommended that motor vehicle occupants use properly fitted seat belts. However, some (but a heretofore unknown number of) countries with national seat belt laws permit various exemptions which may lower use rates. The aim of this study was to survey the variety of exemptions to national seat belt laws.

METHODS

This investigation relied on identifying respondents from national traffic safety agencies, other governmental and non-governmental organizations, Internet searches, personal contacts, and other sources. Questionnaires were deployed through a web based survey supplemented by email and postal versions.

RESULTS

Responses were received from 30 countries of which 28 (93.7%) had a national seat belt law. About two thirds (63.7%) of the 28 national laws applied to both front and back seat passengers. The leading exemption types included vehicles made before a certain year (n = 13), antique vehicles (n = 12), military vehicles (n = 11), buses (n = 9), and emergency vehicles (n = 8). Most responding countries reported one or more specific categories of individuals as exempt including those with medical exemptions (n = 20), taxi drivers (n = 11), police (n = 9), emergency medical personnel (n = 8), physically disabled people (n = 6), and pregnant women (n = 6). Out of 26 responses to the question regarding current level of enforcement, 42.3% felt enforcement was "very good or good" and 57.7% characterized it as "fair or poor".

CONCLUSIONS

This study represents one of the largest international traffic law surveys reported. Most national seatbelt laws offer perilous exemptions to a broad array of vehicle types and road user groups. These findings, coupled with concern over the level of enforcement in the majority of countries surveyed, suggest that international road safety efforts have a long way to go to improve coverage and enforcement of national seat belt laws.

Orexin A mediation of time spent moving in rats: Neural mechanisms

The brain regulates energy balance and spontaneous physical activity, including both small- and large-motor activities. Neural mediators of spontaneous physical activity are currently undefined, although the amount of time spent in sedentary positions versus standing and ambulating may be important in the energetics of human obesity. Orexin A, a neuropeptide produced in caudal hypothalamic areas and projecting throughout the neuraxis, enhances arousal and spontaneous physical activity. To test the hypothesis that orexin A affects the amount of time spent moving, we injected orexin A (0-1000 pmol) into three orexin projection sites in male Sprague-Dawley rats: hypothalamic paraventricular nucleus, rostral lateral hypothalamic area and substantia nigra pars compacta, and measured spontaneous physical activity. Orexin A affects local GABA release and we co-injected orexin A with a GABA agonist, muscimol, in each brain site. Dopamine signaling is important to substantia nigra function and so we also co-injected a dopamine 1 receptor antagonist (SCH 23390) in the substantia nigra pars compacta. In all brain sites orexin A significantly increased time spent vertical and ambulating. Muscimol significantly and dose-dependently inhibited orexin A effects on time spent moving only when administered to the rostral lateral hypothalamic area. In the substantia nigra pars compacta, SCH 23390 completely blocked orexin A-induced ambulation. These data indicate that orexin A influences time spent moving, in three brain sites utilizing separate signaling mechanisms. That orexin A modulation of spontaneous physical activity occurs in brain areas with multiple roles indicates generalization across brain site, and may reflect a fundamental mechanism for enhancing activity levels. This potential for conferring physical activity stimulation may be useful for inducing shifts in time spent moving, which has important implications for obesity.

Neuromedin U in the paraventricular and arcuate hypothalamic nuclei increases non-exercise activity thermogenesis

Brain neuromedin U (NMU) has been associated with the regulation of both energy intake and expenditure. We hypothesized that NMU induces changes in spontaneous physical activity and nonexercise activity thermogenesis (NEAT) through its actions on hypothalamic nuclei. We applied increasing doses of NMU directly to the paraventricular (PVN) and arcuate hypothalamic nuclei using chronic unilateral guide cannulae. In both nuclei, NMU significantly and dose-dependently increased physical activity and NEAT. Moreover, NMU increased physical activity and NEAT during the first hour of the dark phase, indicating that the reduction of sleep is unlikely to account for the increased physical activity seen with NMU treatment. As a positive control, we demonstrated that paraventricular NMU also significantly decreased food intake, as well as body weight. These data demonstrate that NMU is positively associated with NEAT through its actions in the PVN and arcuate nucleus. In co-ordination with its suppressive effects on feeding, the NEAT-activating effects of NMU make it a potential candidate in the combat of obesity.

Elevated hypothalamic orexin signaling, sensitivity to orexin A, and spontaneous physical activity in obesity-resistant rats

Selectively-bred obesity-resistant [diet resistant (DR)] rats weigh less than obesity-prone [diet-induced obese (DIO)] rats, despite comparable daily caloric intake, suggesting phenotypic energy expenditure differences. Human data suggest that obesity is maintained by reduced ambulatory or spontaneous physical activity (SPA). The neuropeptide orexin A robustly stimulates SPA. We hypothesized that DR rats have greater: 1) basal SPA, 2) orexin A-induced SPA, and 3) preproorexin, orexin 1 and 2 receptor (OX1R and OX2R) mRNA, compared with DIO rats. A group of age-matched out-bred Sprague-Dawley rats were used as additional controls for the behavioral studies. DIO, DR, and Sprague-Dawley rats with dorsal-rostral lateral hypothalamic (rLHa) cannulas were injected with orexin A (0, 31.25, 62.5, 125, 250, and 500 pmol/0.5 microl). SPA and food intake were measured for 2 h after injection. Preproorexin, OX1R and OX2R mRNA in the rLHa, and whole hypothalamus were measured by real-time RT-PCR. Orexin A significantly stimulated feeding in all rats. Orexin A-induced SPA was significantly greater in DR and Sprague-Dawley rats than in DIO rats. Two-mo-old DR rats had significantly greater rLHa OX1R and OX2R mRNA than DIO rats but comparable preproorexin levels. Eight-mo-old DR rats had elevated OX1R and OX2R mRNA compared with DIO rats, although this increase was significant for OX2R only at this age. Thus DR rats show elevated basal and orexin A-induced SPA associated with increased OX1R and OX2R gene expression, suggesting that differences in orexin A signaling through OX1R and OX2R may mediate DIO and DR phenotypes.

NEAT--non-exercise activity thermogenesis--egocentric & geocentric environmental factors vs. biological regulation

Non-exercise activity thermogenesis (NEAT) is the energy expenditure of all physical activities other than volitional sporting-like exercise. NEAT includes all those activities that render us vibrant, unique and independent beings such as going to work, playing guitar, toe-tapping and dancing. The factors that account for the 2000 kcal day(-1) variability of NEAT can be categorized as environmental or biological. The environmental determinants of NEAT can be view using one of two models. In the egocentric model we consider a single person as the focus, e.g. 'my job'. In the geocentric model we consider the 'environment' as the focus, e.g. well-lit and safe walk ways. These models provide us with a theoretical framework to understand NEAT and how best to intervene to promote NEAT. As well as environmental effectors of NEAT, there are also biological regulatory mechanisms that enable us to account for three-quarters of the biological variance in susceptibility and resistance to fat gain with human over-feeding. NEAT is likely to be regulated through a central mechanism that integrates NEAT with energy intake and energy stores so that NEAT is activated with over-feeding and suppressed with under-feeding. In conclusion, NEAT is likely to serve as a crucial thermoregulatory switch between energy storage and dissipation that is biologically regulated and influenced, and perhaps over-ridden, by environment. Deciphering the role of NEAT may lead to a better understanding of the pathogenesis, prevention and treatment of obesity.

Differential effects of adrenocorticotropic hormone on human and mouse adipose tissue

Adrenocorticotropic hormone (ACTH) induces lipolysis in a dose-dependent fashion in rodent adipose tissue and adipocytes in vitro. The role of ACTH on lipolysis in human adipose tissue is less clear, however. In this study, we address the hypothesis that ACTH induces lipolysis in human adipose tissue. We used ex vivo organ culture to examine lipolysis in human and mouse adipose tissue. Adipose tissue fragments suspended in culture medium and human ACTH, isoproterenol (positive control), or insulin (negative control) was added in varying concentrations. Lipolysis was measured using glycerol appearance. ACTH receptor mRNA expression was assessed using reverse-transcription polymerase chain reaction (RT-PCR). In mouse adipose tissue, ACTH induced lipolysis in dose-dependent manner; 100 pmol/l ACTH induced 67+/-19% of isoproterenol-stimulated lipolysis and 500 pmol/l ACTH: 86+/-13%. In contrast, human adipose tissue shared no significant response to 100 pmol/l ACTH; ACTH was associated with 9+/-6% and 500 pmol/l of ACTH, 8+/-6% of isoproterenol-stimulated lipolysis. ACTH receptor mRNA was present in mouse adipose tissue, but undetectable in human adipose tissue. These results suggest lipolysis regulation differs between human and mouse adipose tissue in response to ACTH.

Is there a role for gastric accommodation and satiety in asymptomatic obese people?

OBJECTIVE

The relationships of gastric accommodation and satiety in moderately obese individuals are unclear. We hypothesized that obese people had increased gastric accommodation and reduced postprandial satiety. The objective of this study was to compare gastric accommodation and satiety between obese and non-obese asymptomatic subjects.

RESEARCH METHODS AND PROCEDURES

In 13 obese (body mass index [BMI] > or = 30 kg/m(2); mean BMI, 37.0 +/- 4.9 kg/m(2)) and 19 non-obese control subjects (BMI < 30 kg/m(2); mean BMI, 26.2 +/- 2.9 kg/m(2)), we used single photon emission computed tomography to measure fasting and postprandial gastric volumes and expressed the accommodation response as the ratio of postprandial/fasting volumes. The satiety test measured maximum tolerable volume of ingestion of liquid nutrient meal (Ensure) and symptoms 30 minutes after cessation of ingestion.

RESULTS

Total fasting and postprandial gastric volumes and the ratio of postprandial/fasting gastric volume were not different between asymptomatic obese and control subjects. However, the fasting volume of the distal stomach was greater in obese than in control subjects. Maximum tolerable volume of ingested Ensure and aggregate symptom score 30 minutes later were also not different between obese and control subjects.

DISCUSSION

Asymptomatic obese individuals (within the BMI range of 32.6 to 48 kg/m(2)) did not show either increased postprandial gastric accommodation or reduced satiety. These data suggest that gastric accommodation is unlikely to provide an important contribution to development of moderate obesity.

Validation of the Tracmor triaxial accelerometer system for walking

PURPOSE

Walking is likely to contribute substantially to nonexercise activity thermogenesis. The Tracmor triaxial accelerometer system (Maastricht, The Netherlands) is the most widely validated system for detecting body movement in free-living subjects. The aim of this study was to validate the Tracmor triaxial accelerometer system for estimating the energy expenditure of walking.

METHODS

Experiments were conducted in healthy subjects. First, baseline variability for Tracmor output was determined for subjects standing still. Second, Tracmor output was compared for walking on a treadmill and on level ground. Third, both Tracmor output and energy expenditure were compared for walking on a treadmill and walking on level ground. Finally, the effect of gradient on Tracmor output and energy expenditure was compared for subjects walking on a treadmill.

RESULTS

The data demonstrated excellent reproducibility for comparing Tracmor output for standing (CV < 2%). There were excellent log-linear relationships between velocity and Tracmor output walking on a treadmill (r = 0.998) and on level ground (r = 0.999). Tracmor output and the energy expenditure of walking were inseparable for the two modalities of walking. However, the variance in response was such that to reliably derive the relationship between Tracmor output and energy expenditure, separate regression equations are needed for each subject. Finally, the Tracmor accelerometer did not detect the increased energy expenditure of walking that occurs as gradient increases.

CONCLUSION

The Tracmor triaxial accelerometer provides reproducible and reliable data on the body motion associated with walking regardless of whether a subject walks on a treadmill or level ground. Tracmor units can be used to predict the energetic cost of walking provided that separate regression equations are derived for each subject to convert Tracmor output to energy expenditure.

Relationship between duration of pain and secondary signs of obstruction of the urinary tract on unenhanced helical CT

OBJECTIVE

The objective of this study was to investigate the relationship between duration of flank pain and the frequency of secondary signs of ureteral obstruction on unenhanced helical CT.

SUBJECTS AND METHODS

The duration of flank pain was prospectively determined in 227 consecutive patients diagnosed with acute ureterolithiasis on unenhanced helical CT. These CT studies were evaluated for the presence or absence of perinephric stranding, ureteral dilatation, perinephric fluid, collecting system dilatation, periureteral stranding, and nephromegaly. The frequency of each sign was determined as a function of the duration of pain.

RESULTS

The frequency of moderate or severe perinephric stranding increased from 5% at 1--2 hr to 51% at 7--8 hr (p < 0.001); ureteral dilatation increased from 84% at 1--2 hr to 97% at more than 8 hr (p < 0.03); moderate or severe perinephric fluid increased from 0% at 1--2 hr to 22% at 3--4 hr (p < 0.03); collecting system dilatation increased from 68% at 1--2 hr to 89% at 7-8 hr (p < 0.03); periureteral stranding increased from 35% at 1--2 hr to 76% at 7--8 hr (p < 0.004); and nephromegaly increased from 40% at 1--2 hr to 54% at 7--8 hr (p < 0.36).

CONCLUSION

All CT secondary signs of ureteral obstruction except nephromegaly showed a significant increase in frequency as duration of flank pain increased. This observation may explain why the CT studies of some patients with acute ureterolithiasis show negative findings for some or all CT secondary signs of obstruction. Therefore, knowledge of the duration of pain is important when interpreting unenhanced CT studies in patients with acute ureterolithiasis.

Energy expenditure of nonexercise activity

BACKGROUND

We found recently that changes in nonexercise activity thermogenesis (NEAT) mediate resistance to weight gain with overfeeding in sedentary adults. A potentially important, yet seldom investigated, component of NEAT is the energy expenditure of fidgeting-like activities.

OBJECTIVE

Our goal was to measure changes in energy expenditure with fidgeting-like activities.

DESIGN

Energy expenditure was measured in 24 subjects (17 women and 7 men x+/- SD body weight: 76 +/- 21 kg) while recumbent at rest, sitting motionless, standing motionless, partaking of self-selected fidgeting-like movements while seated and while standing, and walking on a treadmill at 1.6, 3.2, and 4.8 km/h (1, 2, and 3 mph). Measurements were performed by using a high-precision, indirect calorimeter connected to the subject via a transparent, lightweight facemask that enabled almost unrestricted movement.

RESULTS

Compared with metabolic rate in the supine position (5.4 +/- 1.5 kJ/min), energy expenditure increased while sitting motionless by 4 +/- 6%, while fidgeting while seated by 54 +/- 29% (P: < 0.0001), while standing motionless by 13 +/- 8% (P: < 0.0001), while fidgeting while standing by 94 +/- 38% (P: < 0.0001), while walking at 1.6 km/h by 154 +/- 38% (P: < 0.0001), while walking at 3.2 km/h by 202 +/- 45% (P: < 0.0001), and while walking at 4.8 km/h by 292 +/- 81% (P: < 0.0001). There was a significant, positive correlation between changes in energy expenditure and body weight for fidgeting-like activities while standing (r = 0.43, P: = 0.02) but not while seated.

CONCLUSIONS

There is marked variance between subjects in the energy expenditure associated with self-selected fidgeting-like activities. The thermogenic potential of fidgeting-like and low-grade activities is sufficiently great to substantively contribute to energy balance.

Energy expenditure in chronic alcohol abuse

BACKGROUND

In healthy subjects, alcohol decreases lipid oxidation favouring fat deposition. However, individuals who chronically abuse alcohol are not obese. To investigate this paradox, we measured energy expenditure (EE) and fuel utilization in chronic alcohol abusers in relation to their drinking behaviour.

METHODS

Resting and postprandial EE and nonprotein respiratory quotient (NPRQ) were measured using indirect calorimetry, in 36 alcohol abusers [mean (+/- SE) age 42 +/- 2 years; weight 67 +/- 2 kg; 21 with steatosis, eight with hepatitis; seven with cirrhosis] and in 36 gender-, age- and weight-matched healthy controls. Alcoholic patients were re-evaluated either after 14 days (n = 14) or on days 2, 4, 6, 8, 14 and 42 (n = 6) after abstinence.

RESULTS

When alcoholics were compared to healthy controls, mean energy intake was greater, 15 +/- 1 MJ day-1 (38 +/- 2% from alcohol) cf. 9 +/- 1 MJ day-1 (P < 0.001), resting EE increased, 82 +/- 2 cf. 65 +/- 2 W (P < 0.001) and NPRQ decreased, 0.75 +/- 0.02 cf. 0.82 +/- 0.01 (P < 0.001). The postprandial increases in EE and NPRQ were of similar magnitude in both groups. Abstinence from alcohol for 14 days was accompanied by reduced energy intake, 16 +/- 1 cf. 11 +/- 1 MJ day-1 (P < 0.005) and decreased resting EE, 84 +/- 5 cf. 73 +/- 4 W (P < 0.05). The decrease in resting EE consistently occurred 4 days after abstinence from alcohol.

CONCLUSIONS

Chronic alcohol abuse is associated with energy wasting and inhibition of adipose tissue accumulation. This may explain why alcoholics are not obese despite high total energy intakes.

Body composition and resting energy expenditure in humans: role of fat, fat-free mass and extracellular fluid

OBJECTIVE

The objective of this study was to determine whether there are independent effects of extracellular fluid volume (ECF) and fat mass (FM) on resting energy expenditure (REE) relative to fat-free mass (FFM) in adult men and women.

METHODS

Multiple linear regression analysis was used to relate REE, as determined by indirect calorimetry, to FFM and FM (measured using dual energy X-ray absorptiometry) and ECF (measured using bromide space and/or the radiosulfate washout space) in 153 women and 100 men with varying amounts of body fat.

RESULTS

REE correlated significantly with FFM and FM in women (r=0.65 and r=0.63, both P<0.001) and men (r=0.62 and r=0.48, both P<0.001, FFM and FM, respectively). In a multiple linear regression analysis FFM, FM and age significantly contributed to the ability to predict REE in both genders. The models that were derived were not significantly different between women and men. In women the contribution to REE from FM was easier to detect when FM was greater. Adjustment of FFM for ECF did not improve the relationship between FFM and REE.

CONCLUSIONS

FFM, FM and age are significant, independent predictors of REE in both men and women. Adjustment of FFM for ECF does not improve the ability of FFM to predict REE, which suggests that ECF is a highly integrated component of FFM in healthy adults. Expressing REE relative to FFM alone will introduce errors when lean and obese populations are compared.

Measuring leg muscle and fat mass in humans: comparison of CT and dual-energy X-ray absorptiometry

Dual-energy X-ray absorptiometry (DEXA) is reported to be inferior to computed tomography (CT) to measure changes in appendicular soft tissue composition. We compared CT- and DEXA-measured thigh muscle and fat mass to evaluate the random and systematic discrepancies between these two methods. Thigh skeletal muscle area (single-slice CT) was suboptimally (r(2) = 0.74, P < 0.0001) related to DEXA-measured thigh fat-free mass (FFM). In contrast, thigh muscle and adipose tissue volumes (multislice CT) were highly related to DEXA-measured thigh FFM and fat (both r(2) = 0.96, P < 0.0001). DEXA-measured leg fat was significantly less than multislice-CT-measured leg adipose tissue volume, whereas multislice-CT-measured leg muscle mass was less (P < 0.0001) than DEXA-measured leg FFM. The systematic discrepancies between the two approaches were consistent with the 10-15% nonfat components of adipose tissue. In conclusion, CT and DEXA measures of appendicular soft tissue are highly related. Systematic differences between DEXA and CT likely relate to the underlying principles of the techniques.

Clinical usefulness of MR imaging of the breast in the evaluation of the problematic mammogram

OBJECTIVE

This study was undertaken to determine the usefulness of MR imaging of the breast as an adjunct to mammography in problematic cases in which the significance, presence, or location of an abnormality could not be determined.

MATERIALS AND METHODS

From January 1993 through February 1998, 86 lesions for which histologic or mammographic follow-up was available were evaluated by breast MR imaging because of equivocal findings on mammography. MR studies were performed with a dedicated breast multicoil on a 1.5-T scanner. Early studies were done using a T1-weighted two-dimensional spin-echo sequence before and after the administration of contrast material. Later studies were performed using a three-dimensional fast spoiled gradient sequence with fat suppression. Studies were considered to be positive for an abnormality if a focal area of enhancement was seen after contrast administration.

RESULTS

MR imaging had positive findings in 38 sites. Twenty-six of these sites corresponded in location to the mammographic abnormality that had prompted the recommendation for MR imaging. The remaining 12 sites occurred in areas not suspected mammographically. At biopsy, 10 (26%) of the 38 positive sites were malignant. MR imaging had negative findings at 60 other sites that had been suspected mammographically. Of these 60 sites, six were treated with excision, all with benign results; the remaining 54 sites showed mammographic stability on follow-up that ranged from 5 to 66 months (mean, 19 months).

CONCLUSION

MR imaging of the breast can be a valuable adjunct to mammography for selected problematic cases.

Leptin responses to overfeeding: relationship with body fat and nonexercise activity thermogenesis

Administration of leptin to rodents results in weight loss through decreased food intake and increased energy expenditure that occurs in part through increased spontaneous activity. In humans, low levels of spontaneous physical activity and below normal plasma leptin concentrations predict subsequent excess weight gain. We recently found that failure to increase nonexercise activity thermogenesis (NEAT) with overfeeding results in greater fat gain in humans, and subsequently evaluated whether changes in leptin are related to NEAT activation. We measured plasma leptin concentrations and adipose tissue leptin messenger ribonucleic acid together with the components of energy expenditure in 16 nonobese humans before and after overfeeding to assess the relationship between leptin responses to overfeeding and the changes in NEAT. Adipocyte leptin expression was up-regulated with overfeeding, and leptin concentrations increased. Leptin concentrations correlated with body fat before and after overfeeding. Changes in leptin with overfeeding were strongly related to changes in body fat, but not to changes in NEAT. Changes in NEAT correlated inversely with fat gain. It is, therefore, unlikely that leptin mediates activation of NEAT with overfeeding in nonobese humans; rather, leptin directly reflects body fat mass and fat mass gain.

Preventing stroke in patients with atrial fibrillation

CONTEXT

Atrial fibrillation, a common disorder that affects nearly one sixth of the population aged 75 years and older, is a major risk factor for stroke.

OBJECTIVES

To review and evaluate the evidence supporting the use of warfarin and/or aspirin for stroke prevention in patients with atrial fibrillation.

DATA SOURCES

Prospective, randomized trials of patients with atrial fibrillation evaluating either warfarin or aspirin or both, from MEDLINE from January 1, 1966, to February 23, 1999.

STUDY SELECTION

Five primary prevention placebo-controlled studies, which had been formally pooled, 1 study evaluating secondary prevention of stroke, 1 study comparing warfarin with aspirin, and 3 studies of warfarin in combination with aspirin were identified.

DATA SYNTHESIS

The risk of developing stroke is heterogeneous and increases with each decade above 65 years; history of high blood pressure, diabetes mellitus, previous transient ischemic attack, or stroke; poor ventricular function; and in women older than 75 years. For patients younger than 65 years, without risk factors, and not receiving antithrombotic therapy, the risk of stroke is 1%/y; those without risk factors between the ages of 65 and 75 years have a risk of 1.1%/y if taking warfarin and 1.4%/y if taking aspirin. For all other patients, stroke risk is reduced from an untreated rate of between 4.3%/y and more than 12%/y to a rate of 1.2%/y to 4%/y with warfarin use.

CONCLUSION

The protection afforded by warfarin is most pronounced in patients at the highest risk for stroke, while aspirin treatment seems adequate in low-risk populations.

Role of nonexercise activity thermogenesis in resistance to fat gain in humans

Humans show considerable interindividual variation in susceptibility to weight gain in response to overeating. The physiological basis of this variation was investigated by measuring changes in energy storage and expenditure in 16 nonobese volunteers who were fed 1000 kilocalories per day in excess of weight-maintenance requirements for 8 weeks. Two-thirds of the increases in total daily energy expenditure was due to increased nonexercise activity thermogenesis (NEAT), which is associated with fidgeting, maintenance of posture, and other physical activities of daily life. Changes in NEAT accounted for the 10-fold differences in fat storage that occurred and directly predicted resistance to fat gain with overfeeding (correlation coefficient = 0.77, probability < 0.001). These results suggest that as humans overeat, activation of NEAT dissipates excess energy to preserve leanness and that failure to activate NEAT may result in ready fat gain.

Preservation of macronutrient preferences in cancer anorexia

Indirect evidence suggests that cancer anorexia is associated with specific aversions to macronutrients. To investigate this, patients with cancer anorexia and hospitalized control subjects devised 3-day menus comprising foods that they wished to eat. These foods were then provided for 3 days and the intakes of each food carefully measured. As expected, patients with cancer anorexia consumed substantially less energy than hospitalized control subjects (6.0 +/- 0.9 MJ vs 9.5 +/- 0.5 MJ, P < 0.001). However, macronutrient composition was consistently maintained in the patients with cancer anorexia. These data argue against cancer anorexia representing a state of macronutrient aversion.

Adenoviral-mediated gene transfer to human adipocytes in vitro, and human adipose tissue ex vivo and rabbit femoral adipose tissue in vivo

Adenoviral-mediated gene transfer has proven useful in several organ systems to understand gene action and to provide a potential therapeutic modality for localized, organ-specific gene overexpression. However, the application of adenoviral-mediated gene transfer to adipocytes and adipose tissue has not been evaluated. We evaluated the feasibility of in vitro and ex vivo transfer of the beta-galactosidase gene to human adipocytes and adipose tissue by means of adenoviral vectors. The efficiency (percentage of cells transduced) of adenoviral-mediated gene transfer of the beta-galactosidase gene to human adipocytes in vitro and to human adipose tissue ex vivo was 21 +/- 3% and 14 +/- 3%, respectively. Adenoviral-mediated gene transfer in a rabbit femoral adipose tissue was also demonstrated in vivo. Adenoviral-mediated gene transfer may facilitate studies on understanding the biology of adipocytes and provide a potential tool for the modulation of adipocyte function in vivo and thereby for the treatment of obesity.

Adipocyte macrophage colony-stimulating factor is a mediator of adipose tissue growth

Adipose tissue growth results from de novo adipocyte recruitment (hyperplasia) and increased size of preexisting adipocytes. Adipocyte hyperplasia accounts for the severalfold increase in adipose tissue mass that occurs throughout life, yet the mechanism of adipocyte hyperplasia is unknown. We studied the potential of macrophage colony-stimulating factor (MCSF) to mediate adipocyte hyperplasia because of the profound effects MCSF exerts on pluripotent cell recruitment and differentiation in other tissues. We found that MCSF mRNA and protein were expressed by human adipocytes and that adipocyte MCSF expression was upregulated in rapidly growing adipose tissue that encircled acutely inflamed bowel and in adipose tissue from humans gaining weight (4-7 kg) with overfeeding. Localized overexpression of adipocyte MCSF was then induced in rabbit subcutaneous adipose tissue in vivo using adenoviral-mediated gene transfer. Successful overexpression of MCSF was associated with 16-fold increases in adipose tissue growth compared with a control adenovirus expressing beta-galactosidase. This occurred in the absence of increased cell size and in the presence of increased nuclear staining for MIB-1, a marker of proliferation. We conclude that MCSF participates in adipocyte hyperplasia and the physiological regulation of adipose tissue growth.

Ureteral calculi in patients with flank pain: correlation of plain radiography with unenhanced helical CT

PURPOSE

To determine the sensitivity and specificity of plain radiography for the detection of ureteral calculi with use of unenhanced helical computed tomography (CT) as the standard of reference.

MATERIALS AND METHODS

Plain radiographs and helical CT scans of 178 patients with acute flank pain were reviewed retrospectively. Three interpretations of plain radiographs were used: (a) Original reading. This was the report made at the time of the patient's evaluation before the patient underwent CT. (b) Blinded retrospective reading. Each plain radiograph was interpreted without knowledge of the CT findings. (c) Unblinded retrospective reading. The plain radiograph of each patient whose CT scan showed a stone was reviewed with the CT scan.

RESULTS

The original reading had a sensitivity of 45% and a specificity of 77% for the detection of ureteral calculi. The blinded retrospective reading had a sensitivity of 59% and a specificity of 71%. The unblinded retrospective reading had a sensitivity of 59% (95% confidence interval: 47%, 70%).

CONCLUSION

Plain radiography is of limited value for aiding the diagnosis of ureteral stones. All patients with acute flank pain for whom radiologic imaging is recommended can directly undergo unenhanced helical CT; plain radiographs need not be obtained first.

Utility of a standardized sign-out card for new medical interns

Conscientious sign-out between medical interns is important for the continuity of care of hospitalized patients. We developed a standardized sign-out card that prompted the intern going off duty to transmit patient care information to the inter on call. The card was tested in a prospective, randomized, controlled trial in which one group of interns used the card, and another group did not. Any instance of poor sign-out was reported on a questionnaire completed by the intern who had been on call the previous night. The group using the sign-out cards reported poor sign-out on 8 nights (5.8% of questionnaires), and the control group reported it on 17 nights (14.9% of questionnaires, p = .016). The card was time-effective and inexpensive, resulted in more complete data recording, and possibly decreased the morbidity associated with poor sign-out.

Weighed dietary intakes in patients with chronic liver disease

Poor dietary intake is assumed to be a major causal factor in the malnutrition observed in patients with chronic liver disease. However, the dietary habits of this patient population are poorly documented. The aim of this study was to assess weighed dietary intakes in hospitalized patients with chronic liver disease. Twenty patients with liver disease (10 men, 10 women; mean +/- SD age, 46.2 +/- 10.9 yr, mean weight, 63.3 +/- 8.0 kg, mean body mass index, 22.1 +/- 2.8 kg/m2; 10 alcoholic, 10 nonalcoholic) and 20 general medical patients, matched for age and sex, underwent a 3-d weighed assessment of dietary intake. No significant differences were observed in food intake or dietary composition between the patients with liver disease and the hospital controls. Patients with alcoholic liver disease showed significant differences in dietary energy, protein, and carbohydrate intakes compared with the patients with nonalcoholic liver disease when data were expressed in absolute terms but not when expressed relative to body weight; dietary composition was similar in both groups. Overall, patients with chronic liver disease, especially those with alcohol-related injury, consume a diet comparable with that ingested by other hospital patients both in amount and composition.

Splinter hemorrhages following arterial puncture

Splinter hemorrhages can be a feature of the antiphospholipid syndrome. We describe a patient in whom splinter hemorrhages developed following radial artery puncture. The implications of this findings in patients with the antiphospholipid syndrome are discussed.

The use of a football helmet to secure a nasogastric tube

We describe the case of a 83-yr-old diabetic woman who, during convalescence for treatment of hyperosmolar nonketotic diabetic coma, required nasogastric intubation for enteral feeding. Her course was complicated by delirium during which time she repeatedly removed the nasogastric tube. A football helmet was used to secure the feeding tube and prevent its premature removal. Thereafter nasogastric feeding was uncomplicated. We recommend the use of a football helmet in patients with delirium who repeatedly remove their nasogastric tubes.

Brunner's gland hamartomas: clinical presentation and pathological features of 27 cases

OBJECTIVES

The aim of this study was to characterize the clinical presentation, pathological features, and outcome of a series of patients with Brunner's gland hamartomas.

METHODS

We reviewed the clinical and pathological features of 27 patients who presented with Brunner's gland hamartomas, and we obtained follow-up information.

RESULTS

Patients (12 men and 15 women) presented predominantly in the fifth and sixth decades of life either with gastrointestinal hemorrhage (n = 10) or obstructive symptoms (n = 10); there were also patients whose tumors were discovered as an incidental finding (n = 7). The tumors were generally pedunculated, were located in the first portion of the duodenum, and were in the range of diameter from 1 to 6 cm. Histologically, the hamartomas were characterized by the presence of nondysplastic, lobulated Brunner's glands with intervening bands of fibrous tissue and variable adipose and lymphoid tissue. Focal sclerosis was found in 93% of the hamartomas, possibly mimicking an adenocarcinoma. Whether managed surgically (24 patients) or endoscopically (three patients), the outcome was uniformly favorable. After a median period of 7-yr-follow-up, no tumors recurred, and no additional morbidity was identified.

CONCLUSIONS

Brunner's gland hamartomas are rare duodenal tumors occurring in middle age that present either with gastrointestinal hemorrhage, obstructive symptoms, or as an incidental finding. Surgical or endoscopic excision is uncomplicated, and the long-term outcome is favorable.

New nonionic triiodinated x-ray contrast media containing the N-(2-hydroxyethyl)aminopropane-2,3-diol side chain

We have found the amino alcohol (HE)APD to be an effective solubilizing and detoxifying agent for triiodinated benzene XRCM. Most of the compounds containing the (HE)APD moiety displayed good solution properties (low osmolality and viscosity) and relatively low toxicities. A general trend was observed in which compounds with low hydrophilicity were more toxic. High hydrophilicity was found to be necessary for low intracisternal toxicity, but is not the only criterion. Use of the 5-glycolamido group provides compounds with high hydrophilicity. When all the properties were compared, the best compounds in this study were found to be the three asymmetrically substituted isophthalamides containing the (HE)APD and APD side chains (4a-c: MP-1556, MP-1683, and MP-1689). These compounds have excellent solution properties (low osmolality and viscosity) and low intravenous and intracisternal toxicities, and compare favorably to current clinical agents.

Are Patients in Favour of General Health Screening?

In order to determine whether patients are in favour of general health screening, two sex-matched groups of patients of similar age from a general practice were studied; a group of 315 consecutive patients who attended the practice and 93 individuals who had not attended the practice for at least 12 months were studied. Individuals in both groups were provided with a short, anonymous questionnaire about their desire for general health screening. Although roughly equal proportions of the attenders (93%) and non-attenders (88%) indicated that general health screening was a ‘good idea’, a significantly greater proportion of the attenders (83%) indicated that they would make an appointment and attend the practice for health screening compared to the non-attenders (66%) (P < 0.002). Similarly, a significantly greater proportion of the attenders (33%) indicated that they would seek general health screening, even if not contacted by their doctor, when compared with the non-attenders (16%) (P < 0.001). Thus patients in this study were greatly in favour of general health screening. However, patients who attended the general practice infrequently may represent a population who are relatively resistant to health screening.

Synthesis and structure-activity studies of alkyl-substituted gamma-butyrolactones and gamma-thiobutyrolactones: ligands for the picrotoxin receptor

A series of gamma-butyrolactones and gamma-thiobutyrolactones possessing a variety of alkyl groups and alkyl-substitution patterns was prepared and evaluated for anticonvulsant and convulsant activity. Behavioral studies performed on these compounds suggest that maximal anticonvulsant activity (against maximal electroshock and pentylenetetrazol) results when three or four carbon atoms are present at the alpha-position. For convulsant potency, a similar dependence on the size of the alkyl chain at the beta-position was observed. Additional gamma-dimethyl groups were found to increase the convulsant potency of a beta-substituted compound and to cause an alpha-substituted anticonvulsant to become a convulsant. In general, sulfur for oxygen heteroatom substitution in the alpha-substituted lactones resulted in improved anticonvulsant potency and spectrum of activity. Binding of these compounds to the picrotoxin site of the GABA receptor complex was demonstrated with a [35S]-tert-butylbicyclophosphorothionate radioligand binding assay. Measurements of brain concentrations for selected compounds supports a hypothesis that correlates binding to the picrotoxin site with the pharmacological effects of these compounds.

The children of teenage mothers: patterns of early childbearing in two generations

Twenty years after a mostly black group of Baltimore women became adolescent mothers, the majority of their first-born children had not become adolescent parents, a finding that challenges the popular belief that the offspring of teenage mothers are themselves destined to become adolescent parents. Almost all of the offspring had had intercourse by age 19. About half of the young women had experienced a pregnancy before that age, and approximately one-third of the young men reported having impregnated a partner before age 19. The Baltimore youths were just as likely to have had a live birth before age 19 as were the children of teenage mothers in a national sample of urban blacks, and both of these groups were more likely to have done so than were the children of older mothers in the national sample. In the Baltimore sample, maternal welfare experience only increased a daughter's likelihood of early childbearing if welfare was received during her teenage years. Within the Baltimore sample, a direct comparison of the daughters who became adolescent mothers with their own mothers at a comparable age reveals that the daughters have bleaker educational and financial prospects than their mothers had, and are less likely to ever have married. These results suggest that today's teenage parents may be less likely than were previous cohorts of adolescent mothers to overcome the handicaps of early childbearing. This trend could portend the growth of an urban underclass, even though only a minority of the offspring of teenage mothers go on to become adolescent parents.

Validation of a computer based system for assessing dietary intake

Dietary intake was assessed in 50 patients in hospital by using a dietary history method and computer based system for data collection and standard food tables to calculate the composition of nutrients. The results were compared with those from a weighed assessment that was calculated by using both food tables and manufacturers' food analyses. The use of the food tables overestimated mean (SEM) individual nutrient intakes by between 2.5% (1.5%) and 15.5% (3.0%). The mean errors associated with the dietary history assessment varied from -23% (7.8%) for fat intake to +21.4% (8.5%) for carbohydrate intake. Overall, 30% of the assessments of total nutrient intakes that were calculated using this method were within -20% to +20% of actual values; 18% were within -10% to +10%. The mean errors associated with the computer based assessment varied from -1.0% (4.3%) for carbohydrate intake to +8.5% (3.4%) for protein intake. Overall, 56% of the assessments of total nutrient intakes were within -20% to +20% of actual intakes; 31% were within -10% to +10%. The computer based system provides an accurate, reproducible, convenient, and inexpensive method for assessing dietary intake.

The significance of learned food aversions in the aetiology of anorexia associated with cancer

The results of 24 h food preference tests have suggested that learned food aversions may be involved in the development of anorexia in tumour bearing rats and in patients with cancer. We have performed similar tests over longer periods, up to 10 days, in male rats implanted with Leydig cell tumours, using semisynthetic diets containing differing proportions of fat, protein and carbohydrate. Tumour growth caused anorexia (16-30% decrease in food intake) and cachexia (78% decrease in body fat and 18% decrease in body protein, but 16% increase in body water). Both tumour bearing and control rats preferred a high carbohydrate diet to a high fat diet regardless of their previous diet: tumour bearing rats showed no evidence of a learned food aversion in these experiments. Tumour bearing rats did show an initial preference for a novel high protein diet when this was offered as an alternative to the normal protein diet they had previously been consuming, but this apparent learned food aversion disappeared on the second day of the test and was in fact reversed on all the subsequent days of the test. However, tumour bearing rats did show a sustained preference for a novel low protein diet when this was offered as an alternative to the normal protein diet they had previously been consuming. These results suggest that anorexia in the tumour bearing rats was not caused by a learned food aversion. However the results do indicate that the tumour bearing rats may have developed a specific aversion to protein in the diet. Leydig cell tumours are known to secrete large amounts of oestradiol. However injections of oestradiol in normal male rats caused an increase in body fat content and had no effect on the rats' preference for dietary protein. Clearly hypersecretion of oestradiol was not responsible for the loss of body fat, the fluid retention and the aversion to dietary protein which characterised the tumour bearing rats. The mechanisms by which tumour growth causes anorexia and cachexia in these rats remains obscure.