Rumination in dementia and its relationship with depression, anxiety, and attentional biases

Rumination (self-referential and repetitive thinking), attentional biases (AB), and impaired cognitive control are theorized as being integral factors in depression and anxiety. Yet, research examining the relationship between rumination, mood, and AB for populations with reduced cognitive control, e.g., people living with dementia (PwD), is lacking. To explore whether literature-based relationships are demonstrated in dementia, PwD (n = 64) and healthy controls (HC) (n = 75) completed an online self-report survey measuring rumination and mood (twice), and a telephone cognitive status interview (once). Rumination was measured as an emotion-regulation style, thinking style, and response to depression. We examined the test-retest reliability of PwD's (n = 50) ruminative-scale responses, ruminative-scale internal consistency, and correlations between rumination, age, cognitive ability, and mood scores. Also, nine participants (PwD = 6, HC = 3) completed an AB measure via eye-tracking. Participants fixated on a cross, naturally viewed pairs of facial images conveying sad, angry, happy, and neutral emotions, and then fixated on a dot. Exploratory analyses of emotional-face dwell-times versus rumination and mood scores were conducted. Except for the HC group's reflective response to depression measure, rumination measures were reliable, and correlation strengths between rumination and mood scores (.29 to .79) were in line with literature for both groups. For the AB measure subgroup, ruminative thinking style scores and angry-face metrics were negatively correlated. The results of this study show that literature-based relationships between rumination, depression, and anxiety are demonstrated in dementia, but the relationship between rumination and AB requires further investigation.

Webcam-Based Eye-Tracking of Attentional Biases in Alzheimer's Disease: A Proof-Of-Concept Study

OBJECTIVES

To measure home-based older adults' attentional biases (AB) using webcam-based eye-tracking (WBET) and examine internal consistency.

METHODS

Twelve participants with and without cognitive impairment completed online self-report anxiety and depression screens, and a 96-trial dot-probe task with eye-gaze tracking. For each trial, participants fixated on a cross, free-viewed sad-neutral, sad-angry, sad-happy, angry-neutral, angry-happy, and happy-neutral facial expression pairings, and then fixated on a dot. In emotional-neutral pairings, the time spent looking (dwell-time) at neutral was averaged and subtracted from the emotional average to indicate biases "away from" (negative score) and "toward" (positive score) each emotional face. Internal consistency was estimated for dwell-times and bias scores using Cronbach's alpha and Spearman - Brown corrected split-half coefficients.

RESULTS

The full-cohort and a comorbid anxious and depressed sub-group (n = 6) displayed AB away from sad faces, and toward angry and happy faces, with happy-face AB being more pronounced. AB indices demonstrated low reliability except sub-group happy-face indices. Happy-face AB demonstrated the highest reliability.

CONCLUSIONS

AB measures were in-line with lab-based eye-tracking literature, providing some support for WBET-based measurement.

CLINICAL IMPLICATIONS

Establishing the feasibility of WBET-based measures is a step toward an objective home-based clinical tool. Literature-based suggestions are provided to improve reliability.

Inertial measurement data from loose clothing worn on the lower body during everyday activities

Embedding sensors into clothing is promising as a way for people to wear multiple sensors easily, for applications such as long-term activity monitoring. To our knowledge, this is the first published dataset collected from sensors in loose clothing. 6 Inertial Measurement Units (IMUs) were configured as a 'sensor string' and attached to casual trousers such that there were three sensors on each leg near the waist, thigh, and ankle/lower-shank. Participants also wore an Actigraph accelerometer on their dominant wrist. The dataset consists of 15 participant-days worth of data collected from 5 healthy adults (age range: 28-48 years, 3 males and 2 females). Each participant wore the clothes with sensors for between 1 and 4 days for 5-8 hours per day. Each day, data were collected while participants completed a fixed circuit of activities (with a video ground truth) as well as during free day-to-day activities (with a diary). This dataset can be used to analyse human movements, transitional movements, and postural changes based on a range of features.

Classification of static postures with wearable sensors mounted on loose clothing

Inertial Measurement Units (IMUs) are a potential way to monitor the mobility of people outside clinical or laboratory settings at an acceptable cost. To increase accuracy, multiple IMUs can be used. By embedding multiple sensors into everyday clothing, it is possible to simplify having to put on individual sensors, ensuring sensors are correctly located and oriented. This research demonstrates how clothing-mounted IMU readings can be used to identify 4 common postures: standing, sitting, lying down and sitting on the floor. Data were collected from 5 healthy adults, with each providing 1-4 days of data with approximately 5 h each day. Each day, participants performed a fixed set of activities that were video-recorded to provide a ground truth. This is an analysis of accelerometry data from 3 sensors incorporated into right trouser-leg at the waist, thigh and ankle. Data were classified as static/ dynamic activities using a K-nearest neighbour (KNN) algorithm. For static activities, the inclination angles of the three sensors were estimated and used to train a second KNN classifier. For this highly-selected dataset (60000-70000 data points/posture), the static postures were classified with 100% accuracy, illustrating the potential for clothing-mounted sensors to be used in posture classification.

Comparing Loose Clothing-Mounted Sensors with Body-Mounted Sensors in the Analysis of Walking

A person's walking pattern can reveal important information about their health. Mounting multiple sensors onto loose clothing potentially offers a comfortable way of collecting data about walking and other human movement. This research investigates how well the data from three sensors mounted on the lateral side of clothing (on a pair of trousers near the waist, upper thigh and lower shank) correlate with the data from sensors mounted on the frontal side of the body. Data collected from three participants (two male, one female) for two days were analysed. Gait cycles were extracted based on features in the lower-shank accelerometry and analysed in terms of sensor-to-vertical angles (SVA). The correlations in SVA between the clothing- and body-mounted sensor pairs were analysed. Correlation coefficients above 0.76 were found for the waist sensor pairs, while the thigh and lower-shank sensor pairs had correlations above 0.90. The cyclical nature of gait cycles was evident in the clothing data, and it was possible to distinguish the stance and swing phases of walking based on features in the clothing data. Furthermore, simultaneously recording data from the waist, thigh, and shank was helpful in capturing the movement of the whole leg.

Effectiveness of Web-Based Personalized Nutrition Advice for Adults Using the eNutri Web App: Evidence From the EatWellUK Randomized Controlled Trial

Background

Evidence suggests that eating behaviors and adherence to dietary guidelines can be improved using nutrition-related apps. Apps delivering personalized nutrition (PN) advice to users can provide individual support at scale with relatively low cost.

Objective

This study aims to investigate the effectiveness of a mobile web app (eNutri) that delivers automated PN advice for improving diet quality, relative to general population food-based dietary guidelines.

Methods

Nondiseased UK adults (aged >18 years) were randomized to PN advice or control advice (population-based healthy eating guidelines) in a 12-week controlled, parallel, single-blinded dietary intervention, which was delivered on the web. Dietary intake was assessed using the eNutri Food Frequency Questionnaire (FFQ). An 11-item US modified Alternative Healthy Eating Index (m-AHEI), which aligned with UK dietary and nutritional recommendations, was used to derive the automated PN advice. The primary outcome was a change in diet quality (m-AHEI) at 12 weeks. Participant surveys evaluated the PN report (week 12) and longer-term impact of the PN advice (mean 5.9, SD 0.65 months, after completion of the study).

Results

Following the baseline FFQ, 210 participants completed at least 1 additional FFQ, and 23 outliers were excluded for unfeasible dietary intakes. The mean interval between FFQs was 10.8 weeks. A total of 96 participants were included in the PN group (mean age 43.5, SD 15.9 years; mean BMI 24.8, SD 4.4 kg/m²) and 91 in the control group (mean age 42.8, SD 14.0 years; mean BMI 24.2, SD 4.4 kg/m²). Compared with that in the control group, the overall m-AHEI score increased by 3.5 out of 100 (95% CI 1.19-5.78) in the PN group, which was equivalent to an increase of 6.1% (P=.003). Specifically, the m-AHEI components nuts and legumes and red and processed meat showed significant improvements in the PN group (P=.04). At follow-up, 64% (27/42) of PN participants agreed that, compared with baseline, they were still following some (any) of the advice received and 31% (13/42) were still motivated to improve their diet.

Conclusions

These findings suggest that the eNutri app is an effective web-based tool for the automated delivery of PN advice. Furthermore, eNutri was demonstrated to improve short-term diet quality and increase engagement in healthy eating behaviors in UK adults, as compared with population-based healthy eating guidelines. This work represents an important landmark in the field of automatically delivered web-based personalized dietary interventions.

Trial Registration

ClinicalTrials.gov NCT03250858; https://clinicaltrials.gov/ct2/show/NCT03250858

E-Commerce Design by Older Adults: The Selection and Placement of Web Objects on Shopping Sites

This study offers insights, gathered from co-design activities with older adults, on the design of e-commerce websites. Twenty older adults (aged 52–75 years) took part in a paper-based design activity in which they were presented with a web browser window, cutouts of a selection of web objects (e.g., product images and “add to cart” buttons) in a range of designs, and office stationery for making annotations and asked to select and place web objects onto the browser window to express their design ideas for two types of shopping experience: purchasing a grocery item that is inexpensive and typically purchased in multiples (carrots) and purchasing an assistive technology item which is considered expensive and normally purchased as a one-off (wheelchair). Objects selected frequently by the older adults for inclusion in both types of e-commerce websites included product images, price, and an “add to cart” button. Some objects were selected for inclusion depending on the type of website—quantity selection was selected for the cheap, multiple purchase item, whereas descriptions, reviews, and shipping/return information were deemed important only for the expensive, single-item purchase. Regarding the relative placement of the “add to cart” button, participants most often placed the button close to the quantity selection and/or the price. Furthermore, participants expressed that having these three elements presented within a visually distinctive “buy box” would be beneficial. This study offers insight into which website elements are deemed important by this older adult participant group for e-commerce websites and how the elements should be arranged, and the results also indicate that some design requirements may differ between different types of shopping experience. The findings can potentially benefit designers, developers, and industries to more fully grasp the potential of usable online shopping applications.

Web-Based Dietary Intake Estimation to Assess the Reproducibility and Relative Validity of the EatWellQ8 Food Frequency Questionnaire: Validation Study

BACKGROUND

The web-based EatWellQ8 food frequency questionnaire (FFQ) was developed as a dietary assessment tool for healthy adults in Kuwait. Validation against reliable instruments and assessment of its reproducibility are required to ensure the accuracy of the EatWellQ8 FFQ in computing nutrient intake.

OBJECTIVE

This study aims to assess the reproducibility and relative validity of the EatWellQ8 146-item FFQ, which included images of food portion sizes based on The Composition of Foods by McCance and Widdowson and food composition tables from Kuwait and the Kingdom of Bahrain, against a paper-based FFQ (PFFQ) and a 4-day weighed food record (WFR).

METHODS

Reproducibility of the EatWellQ8 FFQ was assessed using a test-retest methodology. Participants were required to complete the FFQ at 2 time points, 4 weeks apart. To assess the relative validity of the EatWellQ8 FFQ, a subset of the participants were asked to complete a PFFQ or a 4-day WFR 1 week after the administration of the EatWellQ8 FFQ. The level of agreement between nutrient and food group intakes was estimated by repeated EatWellQ8 FFQ administration. The EatWellQ8 FFQ, PFFQ, and 4-day WFR were also evaluated using the Bland-Altman methodology and classified into quartiles of daily intake. Crude unadjusted correlation coefficients were also calculated for nutrients and food groups.

RESULTS

A total of 99 Kuwaiti participants (64/99, 65% female and 35/99, 35% male) completed the study-53 participated in the reproducibility study and the 4-day WFR validity study (mean age 37.1 years, SD 9.9) and 46 participated in the PFFQ validity study (mean age 36.2 years, SD 8.3). Crude unadjusted correlations for repeated EatWellQ8 FFQs ranged from 0.37 to 0.93 (mean r=0.67, SD 0.14; 95% CI 0.11-0.95) for nutrients and food groups (P=.01). Mean cross-classification into exact agreement plus adjacent was 88% for nutrient intakes and 86% for food groups, and Bland-Altman plots showed good agreement for energy-adjusted macronutrient intakes. The association between the EatWellQ8 FFQ and PFFQ varied, with crude unadjusted correlations ranging from 0.42 to 0.73 (mean r=0.46, SD 0.12; 95% CI -0.02 to 0.84; P=.046). Mean cross-classification into exact agreement plus adjacent was 84% for nutrient intake and 74% for food groups. Bland-Altman plots showed moderate agreement for both energy and energy-controlled nutrient intakes. Crude unadjusted correlations for the EatWellQ8 FFQ and the 4-day WFR ranged from 0.40 to 0.88 (mean r=0.58, SD 0.13; 95% CI 0.01-0.58; P=.01). Mean cross-classification into exact agreement plus adjacent was 85% for nutrient intake and 83% for food groups. Bland-Altman plots showed moderate agreement for energy-adjusted macronutrient intakes.

CONCLUSIONS

The results indicate that the web-based EatWellQ8 FFQ is reproducible for assessing nutrient and food group intake and has moderate agreement compared with a PFFQ and a 4-day WFR for measuring energy and nutrient intakes.

Dietary Quality in Vegetarian and Omnivorous Female Students in Germany: A Retrospective Study

Vegetarian diets have gained in popularity, especially among highly educated women, and are considered beneficial to health. Comparative studies assessing the diet of vegetarians against omnivores are rather limited and often provide ambivalent results. Therefore, this study examined the nutrient intake and nutritional quality of vegetarian and omnivorous diets in a group of 61 female students in Germany. Habitual dietary intake was evaluated using a validated graphical online food frequency questionnaire (FFQ). Differences in nutrient intakes were analyzed by Mann-Whitney-U-Tests. Odds Ratios (OR) were calculated for vegetarians exceeding dietary reference values (DRV) compared to omnivores. The overall nutritional quality was assessed using the Healthy-Eating-Index-2015 (HEI-2015). In omnivores, intakes of total energy from saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), long-chain omega-3 polyunsaturated fatty acids (LC-n3-PUFA), cholesterol, sucrose, lactose, retinol, and cobalamin were significantly higher than in vegetarians. Significantly lower intakes were observed for fiber, magnesium, and beta-carotene. Significant OR were detected for total fat (OR = 0.29), SFA (OR = 0.04), beta-carotene (OR = 4.55), and cobalamin (OR = 0.32). HEI-2015 scores were higher for vegetarians than for omnivores (79 points versus 74 points) and significant differences were recorded for the HEI-2015 components dairy, seafood & plant proteins, fatty acids, added sugars, and saturated fatty acids.

Insights Into the Delivery of Personalized Nutrition: Evidence From Face-To-Face and Web-Based Dietary Interventions

Prevention strategies for non-communicable diseases (NCDs) are a global priority as it has been estimated that NCDs will account for around 73% of worldwide mortality by the year 2020. The adoption of diets that are low in saturated fat, free sugars, and red and processed meats and higher in unsaturated fats, wholegrains, fruit, and vegetables have been shown to reduce the risk of NCDs. With increasing internet use, several nutrition interventions are now being conducted online as well as face-to-face, however it is unclear which delivery method is most effective. Although a consumer preference toward face-to-face dietary advice delivery has been identified previously, interest in delivering web-based dietary advice, and in particular personalized nutrition (PN), has been rising, as internet delivery may be less costly and more scalable. This review compares published face-to-face and web-based dietary interventions to give insight into which dietary method might be more effective for PN. In total, 19 peer-reviewed randomized controlled trials were identified for inclusion in the review. The majority of face-to-face nutrition interventions were successful at facilitating dietary change. Results from web-based nutrition interventions suggested that personalized web-based nutrition interventions may be successful at inducing short-term dietary change compared to standardized dietary interventions, however, minimal evidence of long-term impact has been found across both delivery methods. Results of a trial that compared face-to-face with web-based diet intervention found significantly greater dietary changes in the face-to-face group compared to web-based and control groups. Further controlled comparative studies and cost-benefit analysis are needed to assess whether web-based methods can be used in place of face-to-face interventions for achieving dietary change.

Comparing Clothing-Mounted Sensors with Wearable Sensors for Movement Analysis and Activity Classification

Inertial sensors are a useful instrument for long term monitoring in healthcare. In many cases, inertial sensor devices can be worn as an accessory or integrated into smart textiles. In some situations, it may be beneficial to have data from multiple inertial sensors, rather than relying on a single worn sensor, since this may increase the accuracy of the analysis and better tolerate sensor errors. Integrating multiple sensors into clothing improves the feasibility and practicality of wearing multiple devices every day, in approximately the same location, with less likelihood of incorrect sensor orientation. To facilitate this, the current work investigates the consequences of attaching lightweight sensors to loose clothes. The intention of this paper is to discuss how data from these clothing sensors compare with similarly placed body worn sensors, with additional consideration of the resulting effects on activity recognition. This study compares the similarity between the two signals (body worn and clothing), collected from three different clothing types (slacks, pencil skirt and loose frock), across multiple daily activities (walking, running, sitting, and riding a bus) by calculating correlation coefficients for each sensor pair. Even though the two data streams are clearly different from each other, the results indicate that there is good potential of achieving high classification accuracy when using inertial sensors in clothing.

Electroencephalography reflects the activity of sub-cortical brain regions during approach-withdrawal behaviour while listening to music

The ability of music to evoke activity changes in the core brain structures that underlie the experience of emotion suggests that it has the potential to be used in therapies for emotion disorders. A large volume of research has identified a network of sub-cortical brain regions underlying music-induced emotions. Additionally, separate evidence from electroencephalography (EEG) studies suggests that prefrontal asymmetry in the EEG reflects the approach-withdrawal response to music-induced emotion. However, fMRI and EEG measure quite different brain processes and we do not have a detailed understanding of the functional relationships between them in relation to music-induced emotion. We employ a joint EEG – fMRI paradigm to explore how EEG-based neural correlates of the approach-withdrawal response to music reflect activity changes in the sub-cortical emotional response network. The neural correlates examined are asymmetry in the prefrontal EEG, and the degree of disorder in that asymmetry over time, as measured by entropy. Participants’ EEG and fMRI were recorded simultaneously while the participants listened to music that had been specifically generated to target the elicitation of a wide range of affective states. While listening to this music, participants also continuously reported their felt affective states. Here we report on co-variations in the dynamics of these self-reports, the EEG, and the sub-cortical brain activity. We find that a set of sub-cortical brain regions in the emotional response network exhibits activity that significantly relates to prefrontal EEG asymmetry. Specifically, EEG in the pre-frontal cortex reflects not only cortical activity, but also changes in activity in the amygdala, posterior temporal cortex, and cerebellum. We also find that, while the magnitude of the asymmetry reflects activity in parts of the limbic and paralimbic systems, the entropy of that asymmetry reflects activity in parts of the autonomic response network such as the auditory cortex. This suggests that asymmetry magnitude reflects affective responses to music, while asymmetry entropy reflects autonomic responses to music. Thus, we demonstrate that it is possible to infer activity in the limbic and paralimbic systems from pre-frontal EEG asymmetry. These results show how EEG can be used to measure and monitor changes in the limbic and paralimbic systems. Specifically, they suggest that EEG asymmetry acts as an indicator of sub-cortical changes in activity induced by music. This shows that EEG may be used as a measure of the effectiveness of music therapy to evoke changes in activity in the sub-cortical emotion response network. This is also the first time that the activity of sub-cortical regions, normally considered “invisible” to EEG, has been shown to be characterisable directly from EEG dynamics measured during music listening.

Evaluation of the eNutri automated personalised nutrition advice by users and nutrition professionals in the UK

Nutrition apps have great potential to support people to improve their diets, but few apps give automated validated personalised nutrition advice. A web app capable of delivering automated personalised food-based nutrition advice (eNutri) was developed. The aims of this study were to i) evaluate and optimise the personalised nutrition report provided by the app and ii) compare the personalised food-based advice with nutrition professionals’ standards to aid validation. A study with nutrition professionals (NP) compared the advice provided by the app against professional Registered Dietitians (RD) (n = 16) and Registered Nutritionists (RN) (n = 16) standards. Each NP received two pre-defined scenarios, comprising an individual’s characteristics and dietary intake based on an analysis of a food frequency questionnaire, along with the nutrition food-based advice that was automatically generated by the app for that individual. NPs were asked to use their professional judgment to consider the scenario, provide their three most relevant recommendations for that individual, then consider the app’s advice and rate their level of agreement via 5-star scales (with 5 as complete agreement). NPs were also asked to comment on the eNutri recommendations, scores generated and overall impression. The mean scores for the appropriateness, relevance and suitability of the eNutri diet messages were 3.5, 3.3 and 3.3 respectively.

Popular Nutrition-Related Mobile Apps: An Agreement Assessment Against a UK Reference Method

BACKGROUND

Nutrition-related apps are commonly used to provide information about the user's dietary intake, but limited research has been performed to assess how well their outputs agree with those from standard methods.

OBJECTIVE

The objective of our study was to evaluate the level of agreement of popular nutrition-related apps for the assessment of energy and available macronutrients and micronutrients against a UK reference method.

METHODS

We compared dietary analysis of 24-hour weighed food records (n=20) between 5 nutrition-related apps (Samsung Health, MyFitnessPal, FatSecret, Noom Coach, and Lose It!) and Dietplan6 (reference method), using app versions available in the United Kingdom. We compared estimates of energy, macronutrients (carbohydrate, protein, fat, saturated fat, and fiber), and micronutrients (sodium, calcium, iron, vitamin A, and vitamin C) using paired t tests and Wilcoxon signed-rank tests, correlation coefficients, and Bland-Altman plots. We obtained 24-hour weighed food records from 20 participants (15 female, 5 male participants; mean age 36.3 years; mean body mass index 22.9 kg/m²) from previous controlled studies conducted at the Hugh Sinclair Unit of Human Nutrition, University of Reading, Reading, UK. Participants had recorded their food consumption over a 24-hour period using standard protocols.

RESULTS

The difference in estimation of energy and saturated fat intake between Dietplan6 and the diet apps was not significant. Estimates of protein and sodium intake were significantly lower using Lose It! and FatSecret than using Dietplan6. Lose It! also gave significantly lower estimates for other reported outputs (carbohydrate, fat, fiber, and sodium) than did Dietplan6. Samsung Health and MyFitnessPal significantly underestimated calcium, iron, and vitamin C compared with Dietplan6, although there was no significant difference for vitamin A. We observed no other significant differences between Dietplan6 and the apps. Correlation coefficients ranged from r=-.12 for iron (Samsung Health vs Dietplan6) to r=.91 for protein (FatSecret vs Dietplan6). Noom Coach was limited to energy output, but it had a high correlation with Dietplan6 (r=.91). Samsung Health had the greatest variation of correlation, with energy at r=.79. Bland-Altman analysis revealed potential proportional bias for vitamin A.

CONCLUSIONS

The findings suggest that the apps provide estimates of energy and saturated fat intake comparable with estimates by Dietplan6. With the exception of Lose It!, the apps also provided comparable estimates of carbohydrate, total fat, and fiber. FatSecret and Lose It! tended to underestimate protein and sodium. Estimates of micronutrient intake (calcium, iron, vitamin A, and vitamin C) by 2 apps (Samsung Health and MyFitnessPal) were inconsistent and less reliable. Lose It! was the app least comparable with Dietplan6. As the use and availability of apps grows, this study helps clinicians and researchers to make better-informed decisions about using these apps in research and practice.

Online dietary intake assessment using a graphical food frequency app (eNutri): Usability metrics from the EatWellUK study

Background

With widespread use of the internet, lifestyle and dietary data collection can now be facilitated using online questionnaires as opposed to paper versions. We have developed a graphical food frequency assessment app (eNutri), which is able to assess dietary intake using a validated food frequency questionnaire (FFQ) and provide personalised nutrition advice. FFQ user acceptance and evaluation have not been investigated extensively and only a few studies involving user acceptance of nutrition assessment and advice apps by older adults are published.

Methods

A formative study with 20 participants (including n = 10 ≥60 years) assessed the suitability of this app for adults and investigated improvements to its usability. The outcomes of this formative study were applied to the final version of the application, which was deployed in an online study (EatWellUK) with 324 participants (including n = 53 ≥60 years) in the UK, using different devices (smartphones, tablets and laptops/desktops). Completion times were based on browser timestamps and usability was measured using the System Usability Scale (SUS), scoring between 0 and 100. Products with a SUS score higher than 70 are considered to be good.

Results

In the EatWellUK study, SUS score median (n = 322) was 77.5 (IQR 15.0). Out of the 322 SUS questionnaire completions, 321 device screen sizes were detected by the app. Grouped by device screen size, small (n = 92), medium (n = 38) and large (n = 191) screens received median SUS scores of 77.5 (IQR 15.0), 75.0 (IQR 19.4) and 77.5 (IQR 16.25), respectively. The median SUS scores from younger (n = 268) and older participants (n = 53) were the same. The FFQ contained 157 food items, and the mean completion time was 13.1 minutes (95% CI 12.6–13.7 minutes). Small, medium and large screen devices resulted in completion times of 11.7 minutes (95% CI 10.9–12.6 minutes), 14.4 minutes (95% CI 12.9–15.9 minutes) and 13.6 minutes (95% CI 12.8–14.3 minutes), respectively.

Conclusions

The overall median SUS score of 77.5 and overall mean completion time of 13.3 minutes indicate good overall usability, and equally, comparable SUS scores and completion times across small, medium and large screen sizes indicates good usability across devices. This work is a step toward the promotion of wider uptake of online apps that can provide online dietary intake assessment at-scale, with the aim of addressing pressing epidemiological challenges.

A Comparison of Food Portion Size Estimation by Older Adults, Young Adults and Nutritionists

OBJECTIVES

To investigate the ability of older adults, younger adults and nutritionists to assess portion size using traditional methods versus a computer-based method. This was to inform the development of a novel dietary assessment method for older adults "The NANA system".

DESIGN

Older and younger adults assessed the portion size of self-served portions of foods from a buffet style set up using traditional and computerised portion size assessment aids. Nutritionists assessed the portion size of foods from digital photographs using computerised portion size aids. These estimates were compared to known weights of foods using univariate analyses of covariance (ANCOVA).

SETTING

The University of Sheffield, United Kingdom.

SUBJECTS

Forty older adults (aged 65 years and over), 41 younger adults (aged between 18 and 40 years) and 25 nutritionists.

RESULTS

There was little difference in the abilities of older and younger adults to assess portion size using both assessment aids with the exception of small pieces morphology. Even though the methods were not directly comparable among the test groups, there was less variability in portion size estimates made by the nutritionists.

CONCLUSION

Older adults and younger adults are similar in their ability to assess food portion size and demonstrate wide variability of estimation compared to the ability of nutritionists to estimate portion size from photographs. The results suggest that the use of photographs of meals consumed for portion size assessment by a nutritionist may improve the accuracy of dietary assessment. Improved portion size assessment aids are required for all age groups.

Directed Motor-Auditory EEG Connectivity Is Modulated by Music Tempo

Beat perception is fundamental to how we experience music, and yet the mechanism behind this spontaneous building of the internal beat representation is largely unknown. Existing findings support links between the tempo (speed) of the beat and enhancement of electroencephalogram (EEG) activity at tempo-related frequencies, but there are no studies looking at how tempo may affect the underlying long-range interactions between EEG activity at different electrodes. The present study investigates these long-range interactions using EEG activity recorded from 21 volunteers listening to music stimuli played at 4 different tempi (50, 100, 150 and 200 beats per minute). The music stimuli consisted of piano excerpts designed to convey the emotion of “peacefulness”. Noise stimuli with an identical acoustic content to the music excerpts were also presented for comparison purposes. The brain activity interactions were characterized with the imaginary part of coherence (iCOH) in the frequency range 1.5–18 Hz (δ, θ, α and lower β) between all pairs of EEG electrodes for the four tempi and the music/noise conditions, as well as a baseline resting state (RS) condition obtained at the start of the experimental task. Our findings can be summarized as follows: (a) there was an ongoing long-range interaction in the RS engaging fronto-posterior areas; (b) this interaction was maintained in both music and noise, but its strength and directionality were modulated as a result of acoustic stimulation; (c) the topological patterns of iCOH were similar for music, noise and RS, however statistically significant differences in strength and direction of iCOH were identified; and (d) tempo had an effect on the direction and strength of motor-auditory interactions. Our findings are in line with existing literature and illustrate a part of the mechanism by which musical stimuli with different tempi can entrain changes in cortical activity.

A Web-Based Graphical Food Frequency Assessment System: Design, Development and Usability Metrics

BACKGROUND

Food frequency questionnaires (FFQs) are well established in the nutrition field, but there remain important questions around how to develop online tools in a way that can facilitate wider uptake. Also, FFQ user acceptance and evaluation have not been investigated extensively.

OBJECTIVE

This paper presents a Web-based graphical food frequency assessment system that addresses challenges of reproducibility, scalability, mobile friendliness, security, and usability and also presents the utilization metrics and user feedback from a deployment study.

METHODS

The application design employs a single-page application Web architecture with back-end services (database, authentication, and authorization) provided by Google Firebase's free plan. Its design and responsiveness take advantage of the Bootstrap framework. The FFQ was deployed in Kuwait as part of the EatWellQ8 study during 2016. The EatWellQ8 FFQ contains 146 food items (including drinks). Participants were recruited in Kuwait without financial incentive. Completion time was based on browser timestamps and usability was measured using the System Usability Scale (SUS), scoring between 0 and 100. Products with a SUS higher than 70 are considered to be good.

RESULTS

A total of 235 participants created accounts in the system, and 163 completed the FFQ. Of those 163 participants, 142 reported their gender (93 female, 49 male) and 144 reported their date of birth (mean age of 35 years, range from 18-65 years). The mean completion time for all FFQs (n=163), excluding periods of interruption, was 14.2 minutes (95% CI 13.3-15.1 minutes). Female participants (n=93) completed in 14.1 minutes (95% CI 12.9-15.3 minutes) and male participants (n=49) completed in 14.3 minutes (95% CI 12.6-15.9 minutes). Participants using laptops or desktops (n=69) completed the FFQ in an average of 13.9 minutes (95% CI 12.6-15.1 minutes) and participants using smartphones or tablets (n=91) completed in an average of 14.5 minutes (95% CI 13.2-15.8 minutes). The median SUS score (n=141) was 75.0 (interquartile range [IQR] 12.5), and 84% of the participants who completed the SUS classified the system either "good" (n=50) or "excellent" (n=69). Considering only participants using smartphones or tablets (n=80), the median score was 72.5 (IQR 12.5), slightly below the SUS median for desktops and laptops (n=58), which was 75.0 (IQR 12.5). No significant differences were found between genders or age groups (below and above the median) for the SUS or completion time.

CONCLUSIONS

Taking into account all the requirements, the deployment used professional cloud computing at no cost, and the resulting system had good user acceptance. The results for smartphones/tablets were comparable with desktops/laptops. This work has potential to promote wider uptake of online tools that can assess dietary intake at scale.

Using the NANA toolkit at home to predict older adults' future depression

BACKGROUND

Depression is currently underdiagnosed among older adults. As part of the Novel Assessment of Nutrition and Aging (NANA) validation study, 40 older adults self-reported their mood using a touchscreen computer over three, one-week periods. Here, we demonstrate the potential of these data to predict future depression status.

METHODS

We analysed data from the NANA validation study using a machine learning approach. We applied the least absolute shrinkage and selection operator with a logistic model to averages of six measures of mood, with depression status according to the Geriatric Depression Scale 10 weeks later as the outcome variable. We tested multiple values of the selection parameter in order to produce a model with low deviance. We used a cross-validation framework to avoid overspecialisation, and receiver operating characteristic (ROC) curve analysis to determine the quality of the fitted model.

RESULTS

The model we report contained coefficients for two variables: sadness and tiredness, as well as a constant. The cross-validated area under the ROC curve for this model was 0.88 (CI: 0.69-0.97).

LIMITATIONS

While results are based on a small sample, the methodology for the selection of variables appears suitable for the problem at hand, suggesting promise for a wider study and ultimate deployment with older adults at increased risk of depression.

CONCLUSIONS

We have identified self-reported scales of sadness and tiredness as sensitive measures which have the potential to predict future depression status in older adults, partially addressing the problem of underdiagnosis.

Short-Term and Working Memory Treatments for Improving Sentence Comprehension in Aphasia: A Review and a Replication Study

Although the roles of verbal short-term and working memory on spoken sentence comprehension skills in persons with aphasia have been debated for many years, the development of treatments to mitigate verbal short-term and working memory deficits as a way of improving spoken sentence comprehension is a new avenue in treatment research. In this article, we review and critically appraise this emerging evidence base. We also present new data from five persons with aphasia of a replication of a previously reported treatment that had resulted in some improvement of spoken sentence comprehension in a person with aphasia. The replicated treatment did not result in improvements in sentence comprehension. We forward recommendations for future research in this, admittedly weak at present, but important clinical research avenue that would help improve our understanding of the mechanisms of improvement of short-term and working memory training in relation to sentence comprehension.

Computer-based tools for assessing micro-longitudinal patterns of cognitive function in older adults

Patterns of cognitive change over micro-longitudinal timescales (i.e., ranging from hours to days) are associated with a wide range of age-related health and functional outcomes. However, practical issues of conducting high-frequency assessments make investigations of micro-longitudinal cognition costly and burdensome to run. One way of addressing this is to develop cognitive assessments that can be performed by older adults, in their own homes, without a researcher being present. Here, we address the question of whether reliable and valid cognitive data can be collected over micro-longitudinal timescales using unsupervised cognitive tests.In study 1, 48 older adults completed two touchscreen cognitive tests, on three occasions, in controlled conditions, alongside a battery of standard tests of cognitive functions. In study 2, 40 older adults completed the same two computerized tasks on multiple occasions, over three separate week-long periods, in their own homes, without a researcher present. Here, the tasks were incorporated into a wider touchscreen system (Novel Assessment of Nutrition and Ageing (NANA)) developed to assess multiple domains of health and behavior. Standard tests of cognitive function were also administered prior to participants using the NANA system.Performance on the two "NANA" cognitive tasks showed convergent validity with, and similar levels of reliability to, the standard cognitive battery in both studies. Completion and accuracy rates were also very high. These results show that reliable and valid cognitive data can be collected from older adults using unsupervised computerized tests, thus affording new opportunities for the investigation of cognitive.

Popular Nutrition-Related Mobile Apps: A Feature Assessment

Background

A key challenge in human nutrition is the assessment of usual food intake. This is of particular interest given recent proposals of eHealth personalized interventions. The adoption of mobile phones has created an opportunity for assessing and improving nutrient intake as they can be used for digitalizing dietary assessments and providing feedback. In the last few years, hundreds of nutrition-related mobile apps have been launched and installed by millions of users.

Objective

This study aims to analyze the main features of the most popular nutrition apps and to compare their strategies and technologies for dietary assessment and user feedback.

Methods

Apps were selected from the two largest online stores of the most popular mobile operating systems—the Google Play Store for Android and the iTunes App Store for iOS—based on popularity as measured by the number of installs and reviews. The keywords used in the search were as follows: calorie(s), diet, diet tracker, dietician, dietitian, eating, fit, fitness, food, food diary, food tracker, health, lose weight, nutrition, nutritionist, weight, weight loss, weight management, weight watcher, and ww calculator. The inclusion criteria were as follows: English language, minimum number of installs (1 million for Google Play Store) or reviews (7500 for iTunes App Store), relation to nutrition (ie, diet monitoring or recommendation), and independence from any device (eg, wearable) or subscription.

Results

A total of 13 apps were classified as popular for inclusion in the analysis. Nine apps offered prospective recording of food intake using a food diary feature. Food selection was available via text search or barcode scanner technologies. Portion size selection was only textual (ie, without images or icons). All nine of these apps were also capable of collecting physical activity (PA) information using self-report, the global positioning system (GPS), or wearable integrations. Their outputs focused predominantly on energy balance between dietary intake and PA. None of these nine apps offered features directly related to diet plans and motivational coaching. In contrast, the remaining four of the 13 apps focused on these opportunities, but without food diaries. One app—FatSecret—also had an innovative feature for connecting users with health professionals, and another—S Health—provided a nutrient balance score.

Conclusions

The high number of installs indicates that there is a clear interest and opportunity for diet monitoring and recommendation using mobile apps. All the apps collecting dietary intake used the same nutrition assessment method (ie, food diary record) and technologies for data input (ie, text search and barcode scanner). Emerging technologies, such as image recognition, natural language processing, and artificial intelligence, were not identified. None of the apps had a decision engine capable of providing personalized diet advice.

Computerized Self-Administered Measures of Mood and Appetite for Older Adults: The Novel Assessment of Nutrition and Ageing Toolkit

The "Novel Assessment of Nutrition and Ageing" (NANA) toolkit is a computerized system for collecting longitudinal information about older adults' health and behavior. Here, we describe the validation of six items for measuring older adults' self-reported mood and appetite as part of the NANA system. In Study 1, 48 community-living older adults (aged 65-89 years) completed NANA measures of their current mood and appetite alongside standard paper measures, on three occasions, in a laboratory setting. In Study 2, 40 community-living older adults (aged 64-88 years) completed daily NANA measures of momentary mood and appetite in their own homes, unsupervised, alongside additional measures of health and behavior, over three 7-day periods. The NANA measures were significantly correlated with standard measures of mood and appetite, and showed stability over time. They show utility for tracking mood and appetite longitudinally, and for better understanding links with other aspects of health and behavior.

Music-induced emotions can be predicted from a combination of brain activity and acoustic features

It is widely acknowledged that music can communicate and induce a wide range of emotions in the listener. However, music is a highly-complex audio signal composed of a wide range of complex time- and frequency-varying components. Additionally, music-induced emotions are known to differ greatly between listeners. Therefore, it is not immediately clear what emotions will be induced in a given individual by a piece of music. We attempt to predict the music-induced emotional response in a listener by measuring the activity in the listeners electroencephalogram (EEG). We combine these measures with acoustic descriptors of the music, an approach that allows us to consider music as a complex set of time-varying acoustic features, independently of any specific music theory. Regression models are found which allow us to predict the music-induced emotions of our participants with a correlation between the actual and predicted responses of up to r=0.234,p<0.001. This regression fit suggests that over 20% of the variance of the participant's music induced emotions can be predicted by their neural activity and the properties of the music. Given the large amount of noise, non-stationarity, and non-linearity in both EEG and music, this is an encouraging result. Additionally, the combination of measures of brain activity and acoustic features describing the music played to our participants allows us to predict music-induced emotions with significantly higher accuracies than either feature type alone (p<0.01).

Changes in music tempo entrain movement related brain activity

The neural mechanisms of music listening and appreciation are not yet completely understood. Based on the apparent relationship between the beats per minute (tempo) of music and the desire to move (for example feet tapping) induced while listening to that music it is hypothesised that musical tempo may evoke movement related activity in the brain. Participants are instructed to listen, without moving, to a large range of musical pieces spanning a range of styles and tempos during an electroencephalogram (EEG) experiment. Event-related desynchronisation (ERD) in the EEG is observed to correlate significantly with the variance of the tempo of the musical stimuli. This suggests that the dynamics of the beat of the music may induce movement related brain activity in the motor cortex. Furthermore, significant correlations are observed between EEG activity in the alpha band over the motor cortex and the bandpower of the music in the same frequency band over time. This relationship is observed to correlate with the strength of the ERD, suggesting entrainment of motor cortical activity relates to increased ERD strength.

Automated identification of neural correlates of continuous variables

BACKGROUND

The electroencephalogram (EEG) may be described by a large number of different feature types and automated feature selection methods are needed in order to reliably identify features which correlate with continuous independent variables.

NEW METHOD

A method is presented for the automated identification of features that differentiate two or more groups in neurological datasets based upon a spectral decomposition of the feature set. Furthermore, the method is able to identify features that relate to continuous independent variables.

RESULTS

The proposed method is first evaluated on synthetic EEG datasets and observed to reliably identify the correct features. The method is then applied to EEG recorded during a music listening task and is observed to automatically identify neural correlates of music tempo changes similar to neural correlates identified in a previous study. Finally, the method is applied to identify neural correlates of music-induced affective states. The identified neural correlates reside primarily over the frontal cortex and are consistent with widely reported neural correlates of emotions.

COMPARISON WITH EXISTING METHODS

The proposed method is compared to the state-of-the-art methods of canonical correlation analysis and common spatial patterns, in order to identify features differentiating synthetic event-related potentials of different amplitudes and is observed to exhibit greater performance as the number of unique groups in the dataset increases.

CONCLUSIONS

The proposed method is able to identify neural correlates of continuous variables in EEG datasets and is shown to outperform canonical correlation analysis and common spatial patterns.

Leveraging everyday technology for people living with dementia: a case study

Purpose

– The purpose of this paper is to present the self-described “journey” of a person with dementia (Brian; author 3) in his re-learning of old technologies and learning of new ones and the impact this had on his life.

Design/methodology/approach

– This is a single case study detailing the participant's experiences collaborating with a researcher to co-create methods of facilitating this learning process, which he documented in the form of an online blog and diary entries. These were analysed using NVivo to reveal the key themes.

Findings

– Brian was able to relearn previously used technologies and learn two new ones. This lead to an overarching theme of positive outlook on life supported by person-centredness, identity and technology, which challenged negative perceptions about dementia.

Research limitations/implications

– The paper provides an example of how learning and technology improved the life of one person with dementia. By sharing the approach the authors hope to encourage others to embrace the challenge of designing and developing innovative solutions for people with a dementia diagnosis by leveraging both current mainstream technology and creating novel bespoke interventions for dementia.

Originality/value

– The personal perspective of a person with dementia and his experiences of (re-) learning provide a unique insight into the impact of technology on his life.

Validation of the NANA (Novel Assessment of Nutrition and Ageing) touch screen system for use at home by older adults

Prospective measurement of nutrition, cognition, and physical activity in later life would facilitate early detection of detrimental change and early intervention but is hard to achieve in community settings. Technology can simplify the task and facilitate daily data collection. The Novel Assessment of Nutrition and Ageing (NANA) toolkit was developed to provide a holistic picture of an individual's function including diet, cognition and activity levels. This study aimed to validate the NANA toolkit for data collection in the community. Forty participants aged 65 years and over trialled the NANA toolkit in their homes for three 7-day periods at four-week intervals. Data collected using the NANA toolkit were compared with standard measures of diet (four-day food diary), cognitive ability (processing speed) and physical activity (self-report). Bland-Altman analysis of dietary intake (energy, carbohydrates, protein fat) found a good relationship with the food diary and cognitive processing speed and physical activity (hours) were significantly correlated with their standard counterparts. The NANA toolkit enables daily reporting of data that would otherwise be collected sporadically while reducing demands on participants; older adults can complete the daily reporting at home without a researcher being present; and it enables prospective investigation of several domains at once.

Neural correlates of emotional responses to music: an EEG study

This paper presents an EEG study into the neural correlates of music-induced emotions. We presented participants with a large dataset containing musical pieces in different styles, and asked them to report on their induced emotional responses. We found neural correlates of music-induced emotion in a number of frequencies over the pre-frontal cortex. Additionally, we found a set of patterns of functional connectivity, defined by inter-channel coherence measures, to be significantly different between groups of music-induced emotional responses.

Effects of Target Expansion on Selection Performance in Older Computer Users

Point and click interactions using a mouse are an integral part of computer use for current desktop systems. Compared with younger users though, older adults experience greater difficulties performing cursor positioning tasks, and this can present limitations to using a computer easily and effectively. Target expansion is a technique for improving pointing performance where the target grows dynamically as the cursor approaches. This has the advantage that targets conserve screen real estate in their unexpanded state, yet can still provide the benefits of a larger area to click on. This article presents two studies of target expansion with older and younger participants, involving multidirectional point-select tasks with a computer mouse. Study 1 compares static versus expanding targets, and Study 2 compares static targets with three alternative techniques for expansion. Results show that expansion can improve times by up to 14%, and reduce error rates by up to 50%. Additionally, expanding targets are beneficial even when the expansion happens late in the movement, that is, after the cursor has reached the expanded target area or even after it has reached the original target area. The participants’ subjective feedback on the target expansion are generally favorable, and this lends further support for the technique.

Midpoint perturbation response in haptically-guided movements

This study investigates the human response to impulse perturbations at the midpoint of a haptically-guided straight-line point-to-point movement. Such perturbation response may be used as an assessment tool during robot-mediated neuro-rehabilitation therapy. Subjects show variety in their perturbation responses. Movements with a lower perturbation displacement exhibit high frequency oscillations, indicative of increased joint stiffness. Equally, movements with a high perturbation displacement exhibit lower frequency oscillations with higher amplitude and a longer settling time. Some subjects show unexpected transients during the perturbation impulse, which may be caused by complex joint interactions in the hand and arm.

Mouse movements of motion-impaired users: a submovement analysis

Understanding human movement is key to improving input devices and interaction techniques. This paper presents a study of mouse movements of motion-impaired users, with an aim to gaining a better understanding of impaired movement. The cursor trajectories of six motion-impaired users and three able-bodied users are studied according to their submovement structure. Several aspects of the movement are studied, including the frequency and duration of pauses between submovements, verification times, the number of submovements, the peak speed of submovements and the accuracy of submovements in two-dimensions. Results include findings that some motion-impaired users pause more often and for longer than able-bodied users, require up to five times more submovements to complete the same task, and exhibit a correlation between error and peak submovement speed that does not exist for able-bodied users.

Safety, pharmacokinetics, and antiretroviral activity of intravenous 9-[2-(R)-(Phosphonomethoxy)propyl]adenine, a novel anti-human immunodeficiency virus (HIV) therapy, in HIV-infected adults

9-[2-(R)-(Phosphonomethoxy)propyl]adenine (PMPA) is a nucleotide analogue with potent antiretroviral activity in vitro and in simian models. A randomized, double-blind, placebo-controlled, dose-escalation clinical trial of intravenous PMPA monotherapy was conducted in 20 human immunodeficiency virus (HIV)-infected adults with CD4 cell counts of >/=200 cells/mm3 and plasma HIV RNA levels of >/=10,000 copies/ml. Two dose levels were evaluated (1 and 3 mg/kg of body weight/day). Ten subjects were enrolled at each dose level (eight randomized to receive PMPA and two randomized to receive placebo). On day 1, a single dose of PMPA or placebo was administered by intravenous infusion. Beginning on study day 8, PMPA or placebo was administered once daily for an additional 7 consecutive days. All subjects tolerated dosing without significant adverse events. Mean peak serum PMPA concentrations were 2.7 +/- 0.9 and 9.1 +/- 2.1 microgram/ml in the 1- and 3-mg/kg cohorts, respectively. Serum concentrations declined in a biexponential fashion, with a terminal half-life of 4 to 8 h. At 3 mg/kg/day, a single infusion of PMPA resulted in a 0.4 log10 median decline in plasma HIV RNA by study day 8. Following 7 consecutive days of study drug administration thereafter, the median changes in plasma HIV RNA from baseline were -1.1, -0.6, and 0.1 log10 in the 3-mg/kg/day, 1-mg/kg/day, and placebo dose groups, respectively. Following the final dose in the 3-mg/kg/day cohort, the reduction in HIV RNA was sustained for 7 days before returning toward baseline. Further studies evaluating an oral prodrug of PMPA are under way.

Effects of La3+ on lipid fluidity and structural transitions in human erythrocyte membranes

The effects of La3+ on the structure and function of human erythrocyte membranes were investigated by fluorescence polarization, spin-labeled electron spin resonance (ESR) and differential scanning calorimetry (DSC). The results showed that increasing concentrations of La3+ inhibited (Na(+) + K+)-ATPase and Mg(2+)-ATPase activities. La3+ lowered the lipid fluidity of erythrocyte membranes and induced structural transitions in erythrocyte membranes.

Automatic probe tuning and matching

The problem of automatically tuning and matching a probe is considered, and attention is drawn to the main cause of difficulty: the interaction of tuning and matching mechanisms. The use of a doubly resonant, inductively coupled probe is therefore advocated, for to first order, tuning, and matching are then orthogonal for small perturbations. It is shown that when such a probe is equipped with negative feedback control of tuning and matching elements, driven by error signals derived from a bridge and the NMR spectrometer, stable and rapid automatic tuning and matching are achieved. The importance of approximately correct phasing of the error signals is emphasized, but the restriction of having to have specific cable lengths to achieve this task is removed. The effects of small errors of phasing are then considered and shown to be unimportant for the chosen probe, in contrast to the situation for other, nonorthogonal probe types. Suggestions for orthogonalization of two common capacitively coupled probe designs are made, and a practical instrument design is then given that, with the addition of external components, can also be used if the NMR receiver cannot be pressed into service.

Caffeine-halothane accuracy in MH testing

The accuracy and stability of caffeine and halothane concentrations in liquid Krebs medium were examined. Caffeine-Krebs Ringer's solution in incremental concentrations from 0.25 to 10 mM (N = 8 for each concentration) was serially assayed over a three-year period. Storage was at 4 degrees C. For serial testing of halothane during a five month period, halothane 1% or 3% in carbogen was bubbled through a Krebs solution, contained in muscle baths, either using a roller pump (to eliminate vaporizer back pressure) or using carbogen at a line pressure of 4-6 lbs/in2 (27-41 kPa). Halothane in Krebs was assayed by high pressure liquid chromatography. Caffeine concentrations did not vary for 20 weeks. From then, through 60 weeks, concentrations less than 2 mM steadily diminished; after that, through 156 weeks, only 4, 8, and 10 mM were stable. When compared to the halothane concentration in gas entering the muscle baths, halothane concentration in Krebs was predictable regardless of method delivery, as long as a gas analyzer indicated the proper concentration. We conclude that caffeine solutions are stable for 20 weeks when refrigerated, and for three years at concentrations 4 mM or greater.

Interaction of the interdigitated DPPG or DPPG/DMPC bilayer with human erythrocyte band 3: differential scanning calorimetry and fluorescence studies

Human erythrocyte band 3 reconstituted into phospholipid vesicles has been used for studying the interaction of interdigitated lipid bilayer with an integral membrane protein. The interdigitated gel phase in DPPG/band 3 or DPPG/DMPC/band 3 systems was induced with polymyxin B (PMB) or Tris+. The phase transitions of the vesicles were detected with high-sensitivity differential scanning calorimetry (DSC). The results indicated that band 3 does not cause significant alterations in the interdigitated phase of phospholipids, with only a little decrease of the phase transition enthalpies. Fluorescence measurements showed that the transition of phospholipid/band 3 systems from the non-interdigitated to interdigitated phase is accompanied by marked intrinsic fluorescence changes of band 3. The interdigitated phase of DPPG or DPPG/DMPC vesicles increases the intrinsic fluorescence intensity of band 3 and significantly decreases the accessibility of certain tryptophan residues on the protein to Cs+.

Effect of lanthanide ions on the phase behavior of dipalmitoylphosphatidylcholine multilamellar liposomes

The effect of lanthanide ions (Ln3+) and their coordination compounds of diethylenetriamine pentaacetic acid (DTPA) on the phase behavior of dipalmitoylphosphatidylcholine (DPPC) multi-lamellar liposomes has been studied by differential scanning calorimetry (DSC), Raman spectroscopy, and freeze-fracture electron microscopic techniques. The displacement of Ca2+ binding on DPPC liposomes by lanthanide ions was also studied. The results show that the binding degree of four kinds of chloride salts with DPPC liposomes is: YbCl3 > GdCl3 > LaCl3 > CaCl2. Lanthanide ions increase the phase transition temperature of DPPC liposomes and decrease the membrane fluidity. Freeze-fracture electron microscopic results show that La3+ enhances the order of DPPC membrane. The effect of coordination compounds of lanthanides with DTPA on the phase behavior of DPPC liposomes is smaller than that of their chlorides. La3+, Gd3+, and Yb3+, can displace Ca2+ binding on DPPC liposomes, but there coordination compounds of DTPA can hardly displace Ca2+. Raman spectroscopic results show that a very slight effect in lateral packing order of DPPC liposomes was observed at various concentrations of lanthanides.

Anisodamine causes acyl chain interdigitation in phosphatidylglycerol

The effect of anisodamine on the structure of the gel phase and the properties of the acyl chain disordering transition of dipalmitoylphosphatidylglycerol (DPPG) has been studied through high-sensitivity differential scanning calorimetry (DSC) and fluorescence polarization measurements of 16-(9-anthroyloxyl)-palmitic acid (16AP) and 3-(9-anthroyloxyl)-stearic acid (3AS), labeling, respectively, the ends and the third carbon of the acyl chains. The non-interdigitated DPPG multilamellar vesicles formed in HEPES buffer show clear fluidity gradient in their acyl chains, whereas the fluidity gradients are completely abolished in the presence of anisodamine. The DSC results showed that the phase transition temperature (Tm) of DPPG is decreased and the enthalpy (delta H) is increased by anisodamine, while the pre-transition vanishes. At 3 mM anisodamine, the delta H of DPPG reaches 9.6 kcal/mol. It can be concluded that DPPG forms an interdigitated gel phase in the presence of anisodamine. A molecular scheme for the interaction of anisodamine with DPPG is proposed.

Phase transitions of Acholeplasma laidlawii membranes. The involvement of Mg(2+)-ATPase in the C transition

Highly sensitive differential scanning calorimetry has been employed to study the phase transitions of A. laidlawii membrane. The DSC curves obtained show five distinct transitions between 20 and 80 degrees C which contain a reversible lipid thermotropic transition at about 37 degrees C and four irreversible denaturation transitions of the membrane proteins occurred at about 44 degrees C, 52 degrees C, 62 degrees C, and 67 degrees C, respectively. Total enthalpy of the thermal denaturation of membrane proteins is 3.4 +/- 0.5 cal/g. Further study of A. laidlawii membrane preparations by means of thermal gel analysis and enzyme activity measurements at various temperatures provided information that the third peak (C transition) of the DSC curve involved primarily with Mg(2+)-ATPase on A. laidlawii membranes.

Effect of hydroxyl radical on Na(+)-K(+)-ATPase activity of the brain microsomal membranes

Sphingomyelin liposomes and brain microsomes were oxidized by exposure to hydrogen peroxide and ferrous ion. Lipid peroxidation were measured by the formation of thiobarbituric acid- reactive substances (TBAR). Hydroxyl radical was detected using the spin- trapping technique. Incubation of sphingomyelin liposomes with H2O2-Fe2+ resulted in an increase in the formation of TBAR. Na(+)-K(+)-ATPase activity was markedly inhibited and the SH group content decreased during incubation of microsomes in the presence of H2O2-Fe2+. Sodium ferulate effectively inhibited TBAR formation, protected Na(+)-K(+)-ATPase activity and prevented the oxidative modification of SH groups. Spin-trapping experiments showed that sodium ferulate effectively scavenged the hydroxyl radicals.

Definition of microsatellite size variants for Tnfa and Hsp70 in autoimmune and nonautoimmune mouse strains

We have cloned and sequenced the upstream regulatory region of tumor necrosis factor alpha (Tnfa) gene in 12 different mouse strains and identified an allelic polymorphism in the upstream regulatory region of the mouse Tnfa gene. The TNF allele found in the NZW strain is distinct from those of all other H-2 haplotypes, supporting our previous suggestion that this allele may be associated with a regulatory or structural defect. In addition, simple tandem repeat sequences (microsatellites) within the promoter region of the Tnfa gene and the 3' untranslated region of one of the members of the HSP70 family (Hsp68c clone) were utilized as genetic markers. Ten TNF size variants and twelve HSP70 variants were identified in over forty mouse strains. Using these markers in a set of congenic mice, we mapped this member of the HSP70 family to the central portion of the H-2 complex, centromeric to the Tnfa gene. The NOD and NZW strains carry unique HSP70 alleles based on the variability in the length of this marker. These findings raise the possibility that this protein may play a role in the association of the major histocompatibility complex with these autoimmune diseases.

Tumor necrosis factor alpha in murine systemic lupus erythematosus disease models: implications for genetic predisposition and immune regulation

Recombinant tumor necrosis factor alpha (TNF-alpha) administration significantly delayed the development of lupuslike nephritis in the New Zealand black x New Zealand white (NZB x NZW)F1 and to a lesser extent in the MRL-lpr/lpr model systems. TNF-alpha treatment was effective when treatment was initiated at 2, 3, or 4 months of age but was ineffective if initiated as late as 6.5 months of age. Treatment of (NZB x NZW)F1 mice for 3 months was more effective than treatment continued for 6 months. Anti-TNF-alpha antibodies did not develop in these mice. Flow microfluorometry analysis showed no major effects on B, T, or monocyte cell population in cells from the peritoneum, spleen, lymph node, and thymus. A decrease in class II Ia expression on macrophages in the peritoneum of TNF-alpha-treated mice was noticed. A correlation between the level of TNF-alpha inducibility in vitro and the effect of TNF-alpha administration in vivo could be shown. Although a limited polymorphism could be shown by restriction fragment length polymorphism, using an amplified (AC)n microsatellite located in the 5' regulatory region of TNF-alpha, a much more extensive interallelic polymorphism was found. The AC microsatellite allele found in NZW mice was unique and different from other lupus strains and nonautoimmune strains. These results have possible implications to the pathogenesis of systemic lupus erythematosus.

Expression of protein kinase C isoenzymes in thymocyte subpopulations and their differential regulation

The expression of the different protein kinase C (PKC) isozymes in mouse thymocytes was studied to determine if there is a correlation between isozyme expression and thymocyte phenotype. Expression of PKC isozymes in thymocyte subsets (distinguished by the CD4 or CD8 Ag) was determined by message amplification phenotyping. The expression of mRNA for PKC-alpha, -beta, -epsilon, and -zeta, but not -gamma or -delta isozymes, was detected in all of the unstimulated thymocyte subpopulations analyzed. Thus no differences in the pattern of PKC isozyme expression were found that could be correlated with thymocyte phenotype. However, it was noted that the levels of PKC mRNA expression were affected by different stimuli in unfractionated thymocytes. Whereas mRNA levels of PKC-alpha and -beta were down-regulated by PMA and ionomycin treatment, no significant changes were seen in the levels of PKC-epsilon mRNA with these agents. PKC-epsilon mRNA decreased in thymocytes exposed to Con A similar to what has been reported for PKC-epsilon protein. PKC-zeta mRNA was also down-regulated by PMA or ionomycin, and the combination of both compounds caused a more rapid and drastic effect. Finally, PKC-delta mRNA expression was induced transiently in thymocytes only after exposure to PMA or Con A, and this induction was inhibited by ionomycin treatment. These results indicate that message levels of specific isoforms of PKC are uniquely regulated and suggest an additional level of control of PKC activity in activated lymphocytes.

Expression of protein kinase C isoenzymes in thymocyte subpopulations and their differential regulation

The expression of the different protein kinase C (PKC) isozymes in mouse thymocytes was studied to determine if there is a correlation between isozyme expression and thymocyte phenotype. Expression of PKC isozymes in thymocyte subsets (distinguished by the CD4 or CD8 Ag) was determined by message amplification phenotyping. The expression of mRNA for PKC-alpha, -beta, -epsilon, and -zeta, but not -gamma or -delta isozymes, was detected in all of the unstimulated thymocyte subpopulations analyzed. Thus no differences in the pattern of PKC isozyme expression were found that could be correlated with thymocyte phenotype. However, it was noted that the levels of PKC mRNA expression were affected by different stimuli in unfractionated thymocytes. Whereas mRNA levels of PKC-alpha and -beta were down-regulated by PMA and ionomycin treatment, no significant changes were seen in the levels of PKC-epsilon mRNA with these agents. PKC-epsilon mRNA decreased in thymocytes exposed to Con A similar to what has been reported for PKC-epsilon protein. PKC-zeta mRNA was also down-regulated by PMA or ionomycin, and the combination of both compounds caused a more rapid and drastic effect. Finally, PKC-delta mRNA expression was induced transiently in thymocytes only after exposure to PMA or Con A, and this induction was inhibited by ionomycin treatment. These results indicate that message levels of specific isoforms of PKC are uniquely regulated and suggest an additional level of control of PKC activity in activated lymphocytes.