A new wearable stretch sensor array for 3D spine model visualization during therapeutic exercise.

Mobile visualization of the spine during therapeutic exercise may unlock the potential benefits of biofeedback for home-based therapy and fitness programs. In this paper we present the design and validation of a new approach to wearable sensors to close the digital-physical gap between sensor data and 3D spine posture by supporting animation of a customizable 3D thoracolumbar spine model that may eventually enable a mobile, virtual reality (VR) visual biofeedback. First, we propose a linear model of the dependency between four stretch signals from the dorsal surface and the angular positions of the thoracolumbar spine on the sagittal, coronal, and transverse planes. We then describe validation experiments and demonstrate the concept by animating the spine model with monoaxial, biaxial and tri-axial motions. The linear model was validated using a 3-way comparison of exercise video, sensor signals, and spine model animation. The computed angular positions were consistent with the video recording, and the animation of the model was visually accurate with a mean absolute error of 3.62 ° for single axis motions and 8.74 ° for dual axis motions. At the end, we provide a discussion on improvements to the linear model performance for cross-axial interactions, plus an outlook of future work.

Microglia-derived IL-1ß triggers p53-mediated cell cycle arrest and apoptosis in neural precursor cells.

Neurogenesis persists in the adult brain and can contribute to learning and memory processes and potentially to regeneration and repair of the affected nervous system. Deregulated neurogenesis has been observed in neuropathological conditions including neurodegenerative diseases, trauma and stroke. However, the survival of neural precursor cells (NPCs) and newly born neurons is adversely affected by the inflammatory environment that arises as a result of microglial activation associated with injury or disease processes. In the present study, we have investigated the mechanisms by which microglia affect NPC proliferation and survival. Importantly, we demonstrate that interleukin-1ß (IL-1ß) produced by lipopolysaccharide/interferon-γ-activated microglia is necessary to induce cell cycle arrest and apoptosis in NPCs in vitro. Mechanistically, we show that IL-1ß activates the tumor suppressor p53 through an oxidative stress-dependent mechanism resulting in p53-mediated induction of the cyclin-dependent kinase inhibitor p21 and the proapoptotic Bcl-2 (B-cell lymphoma-2) family members Puma (p53-upregulated modulator of apoptosis) and Noxa. Furthermore, we demonstrate that cell cycle arrest and apoptosis induced by recombinant IL-1ß or activated microglia is attenuated in p53-deficient NPCs. Finally, we have determined that IL-1ß induces NPC death via the p53-dependent induction of Puma leading to the activation of a Bax (Bcl-2-associated X protein)-mediated mitochondrial apoptotic pathway. In summary, we have elucidated a novel role for p53 in the regulation of NPC proliferation and survival during neuroinflammatory conditions that could be targeted to promote neurogenesis and repair in a number of neurological conditions.

Long-term survival following delayed presentation and resection of colorectal liver metastases.

BACKGROUND: Long-term survival from metastatic colorectal cancer is partly dependent on favourable tumour biology. Large case series have shown improved survival following hepatectomy for colorectal liver metastases (CRLM) in patients diagnosed with metastases more than 12 months after index colorectal surgery (metachronous), compared with those with synchronous metastases. This study investigated whether delayed hepatic resection for CRLM affects long-term survival. METHODS: Consecutive patients undergoing hepatic resection for CRLM in a single centre (1987-2007) were grouped according to the timing of hepatectomy relative to index bowel surgery: less than 12 months (synchronous; group 1), 12-36 months (group 2) and more than 36 months (group 3). Cancer-specific survival was calculated using Kaplan-Meier analysis. RESULTS: There were 577 patients (48·0 per cent) in group 1, 467 (38·9 per cent) in group 2 and 158 (13·1 per cent) in group 3. The overall 5-year cancer-specific survival rate after liver surgery was 42·3 per cent, with no difference between groups. However, when measured from the time of primary colorectal surgery, group 3 showed a survival advantage at both 5 and 10 years (94·1 and 47·6 per cent respectively) compared with groups 1 (46·3 and 24·9 per cent) and 2 (57·1 and 35·0 per cent) (P = 0·003). Survival graphs showed a steeper negative gradient from 5 to 10 years for group 3 compared with groups 1 and 2 (-0·80 versus - 0·34 and - 0·37), indicating an accelerated mortality rate. CONCLUSION: Patients undergoing delayed liver resection for CRLM have a survival advantage that is lost during long-term follow-up.

Hair MDMA samples are consistent with reported ecstasy use: findings from a study investigating effects of ecstasy on mood and memory.

AIMS: Our group has conducted several Internet investigations into the biobehavioural effects of self-reported recreational use of MDMA (3,4-methylenedioxymethamphetamine or Ecstasy) and other psychosocial drugs. Here we report a new study examining the relationship between self-reported Ecstasy use and traces of MDMA found in hair samples. METHODS: In a laboratory setting, 49 undergraduate volunteers performed an Internet-based assessment which included mood scales and the University of East London Drug Use Questionnaire, which asks for history and current drug use. They also provided a hair sample for determination of exposure to MDMA over the previous month. RESULTS: Self-report of Ecstasy use and presence in hair samples were consistent (p < 0.00001). Both subjective and objective measures predicted lower self-reported ratings of happiness and higher self-reported stress. Self-reported Ecstasy use, but not presence in hair, was also associated with decreased tension. CONCLUSION: Different psychoactive drugs can influence long-term mood and cognition in complex and dynamically interactive ways. Here we have shown a good correspondence between self-report and objective assessment of exposure to MDMA. These data suggest that the Internet has potentially high utility as a useful medium to complement traditional laboratory studies into the sequelae of recreational drug use.

Comparison of anthropometry to DXA: a new prediction equation for men.

OBJECTIVE: This study compared three professionally recommended anthropometric body composition prediction equations for men to dual energy X-ray absorptiometry (DXA), and then developed an updated equation, DXA Criterion (DC) from DXA. DESIGN: Cross-sectional. SETTING: Exercise Physiology Lab. University of Missouri-Columbia, USA. SUBJECTS: A total of 160 men aged 18-62 y old. INTERVENTIONS: Percent body fat (%BF) by anthropometry was compared to DXA on the same day. RESULTS: Although %BF was significantly correlated (r=0.923-0.942) (P<0.01) with DXA for all three equations, each equation underestimated %BF (range=3.1-3.3%) (P<0.01) compared to DXA. The following DC equation for men was created: %BF=0.465+0.180(Sigma7SF)-0.0002406(Sigma7SF)(2)+0.06619(age); (Sigma7SF=sum of chest, midaxillary, triceps, subscapular, abdomen, suprailiac, thigh; age=years). The predicted residual sum of squares (PRESS) R(2) was high (0.90) and the PRESS standard error of estimates was excellent (2.2% at the mean) for the DC equation when applied to our sample of 160 men. CONCLUSIONS: The currently recommended anthropometric equations for men underestimate %BF compared to DXA. The DC equation yields a more accurate estimation of %BF in men aged 18-62 y old. The results from this study support the need for the current %BF standards and norms for men to be adjusted upward.

Effects of habitual physical activity on the resting metabolic rates and body compositions of women aged 35 to 50 years.

OBJECTIVE: To examine the effect habitual physical activity has on resting metabolic rate (RMR) and body composition (fat-free mass[FFM], fat mass, and percent body fat) in active compared to sedentary adult women. DESIGN: RMR was measured (by indirect calorimetry) twice after a 12-hour fast at the same point of the menstrual cycle and 48 hours after exercise. FFM, fat mass and percent body fat were measured using whole body air displacement plethysmography. Energy intake and expenditure were determined using 7-day weighed-food records and activity logs. SUBJECTS: Healthy, weight-stable premenopausal women aged 35 to 50 years classified as either active (approximately 9 hours per week of physical activity for 10 or more years) (n= 18) or sedentary (approximately 1 hour per week of physical activity) (n= 14). STATISTICAL ANALYSES: Analysis of covariance was used to investigate differences in mean RMR (kcal/day) between the groups adjusted for FFM, and independent t tests were used to determine differences in demographic, energy expenditure, and diet variables. RESULTS: Percent body fat and fat mass were lower (P<.0005) and RMR (adjusted for FFM) was significantly higher in the active women (P=.045) compared with sedentary controls. In the active and sedentary groups respectively, mean adjusted RMR was 1,510 kcal/day and 1,443 kcal/day, body fat was 18.9% and 28.8%, and fat mass was 11.1 kg and 18.8 kg. Groups were similar in body mass, FFM, body mass index, and age. Mean energy balance appeared to be more negative in the active group (P=.0059) due to significantly higher mean self-reported energy expenditures (P=.0001) and similar mean self-reported energy intakes (P=.52) compared with sedentary controls. These data indicate that active women who participate in habitual physical activity can maintain lower body fat and a higher RMR than sedentary controls with similar body mass, FFM, and body mass index. APPLICATIONS/CONCLUSIONS: This research supports and emphasizes the benefits of habitual physical activity in maintaining RMR and lower body fat levels in middle-aged women.

Postexercise oxygen consumption and substrate use after resistance exercise in women.

OBJECTIVE: This study investigated the acute effects of 45 min of resistance exercise (RE) on excess postexercise oxygen consumption (EPOC) and substrate oxidation 120 min after exercise in moderately trained women. METHODS: Ten RE trained women (age = 29 +/- 3 yr; ht = 168 +/- 8.3 cm; wt = 59 +/- 5.7 kg; VO2max = 38.3 +/- 4.7 mL.kg-1.min-1) underwent two trials: control sitting and RE. Subjects acted as their own controls in a random counterbalanced design. A 2-d nonexercise period was established between testing trials. Oxygen consumption (VO2) and respiratory exchange ratio (RER) were measured continuously by indirect calorimetry before, during, and after exercise and on a separate control day. RE consisted of 3 sets of 10 exercises at 10-repetition maximum with a 1-min rest period between each set. Fingertip samples of blood lactate concentration [BL] were collected immediately postexercise and every 30 min thereafter until [BL] returned to resting baseline values after exercise. RESULTS: The overall 2-h EPOC was 6.2-L (RE = 33.4 +/- 5.1 L vs control = 27.2 +/- 0.3 L), corresponding to an 18.6% elevation over the control period. RER was significantly (P < 0.01) below the control RER from minute 30 to minute 120 postexercise (RE = 0.75 +/- 0.01 vs control = 0.85 +/- 0.01). During the last 30 min of recovery, VO2 and [BL] had returned to control/baseline values and fat oxidation was significantly (P < 0.0001) higher (29.2 vs 16.3 kcal) after RE compared with the control trial. CONCLUSION: These data indicate that in young RE trained women, acute RE produces a modest increase in VO2 during a 2-h recovery period and an increase in fat oxidation.

Anthropometry and bioelectrical impedance inconsistently predicts fatness in women with regional adiposity.

PURPOSE: This investigation examined the accuracy of several generalizable anthropometric (ANTHRO) and bioelectrical impedance (BIA) regression equations to estimate % body fat (%BF) in women with either upper body (UB) or lower body (LB) fat distribution patterns. METHODS: Thirty-six premenopausal women were individually matched for age (X = 38.6 +/- 6.6 yr), BMI (X = 25.5 +/- 4.2 kg x m(-2)) and %BF (30.3 +/- 8.1%; hydrostatic, [UWW]) and placed by waist to hip ratio (WHR) into two distinct groups: LB (N = 18; WHR < or = 0.73) and UB (N = 18; WHR > or = 0.80). Equations tested were ANTHRO: Jackson et al. (JPW-7 and 3 site), 1980; Durnin and Womersley (DW), 1974; Tran and Weltman (TW), 1989; and Vogel et al. (V), 1988; BIA: Lohman (L), 1992; Gray et al. (G), 1989; and VanLoan and Mayclin (VLM), 1987. Circumference and skinfold measures were made by a trained technician. BIA (Vallhalla, 1990B) measures were taken 4 h postprandially under controlled conditions of water intake and exercise. %BF by UWW (criterion) was not different between groups (UB = 30.8 +/- 8.2%; LB = 29.7 +/- 8%). RESULTS: In the UB group, three of five ANTHRO equations significantly overestimated %BF by approximately 6% (range = 3-8%) as compared with UWW. BIA overestimated %BF in UB by 5% using G and in both groups by about 6% using VLM, whereas L underestimated %BF in LB by about 4%. CONCLUSION: We conclude that ANTHRO and some BIA equations are accurate for predicting %BF in LB fat "shaped" women but are not appropriate for women with primarily abdominal fat patterning.

Association of negative and positive social ties with fibrinogen levels in young women.

The associations between positive and negative aspects of social relationships and fibrinogen, a risk factor for coronary heart disease (CHD), were examined in young, healthy women recruited from the community (n = 46) and from a college campus (n = 42). For community women, the perception that individuals in their social networks frequently undermined them was related to higher fibrinogen, independent of perceived frequency of support. For college women, fibrinogen was elevated among women with frequent undermining only when they also reported infrequent support. After controlling for other risk factors, the associations between social ties and fibrinogen remained significant in both samples. These results indicate that positive and negative social ties are associated with fibrinogen levels and suggest that social relationships may affect CHD risk in part through their influence on fibrinogen.

Substrate utilization and work efficiency during submaximal exercise in vitamin C depleted-repleted adults.

A placebo-controlled, depletion-repletion protocol was utilized to examine the effect of vitamin C status on substrate utilization during a 90 min walk at 50% maximal oxygen consumption (VO2max). Nine vitamin C depleted subjects (plasma vitamin C < 28 mumol/L) agreed to participate in the 5-week study (aged, 27.6 +/- 2.5 years, mean +/- SE; 5 females, 4 males). Subjects were apparently healthy but unaware of their vitamin C status. Prior to the experimental period, VO2max was measured using open-circuit spirometry during a graded walking protocol. Subjects ingested a placebo capsule daily during weeks 1-3 and a 500 mg vitamin C capsule daily during weeks 4-5 of the experimental study. Mean plasma vitamin C rose nearly 3-fold and mean plasma carnitine fell by nearly 20% at repletion (week 5) versus depletion (week 3). At the end of weeks 3 and 5, subjects completed a 90 minute treadmill walk at an exercise intensity of 50% VO2max. The relative contribution of fat utilized for energy during walking did not differ in the vitamin C depleted versus repleted states. However, work performed by subjects and gross efficiency during exercise increased significantly at repletion versus depletion (10% and 15%, respectively). These data indicate that vitamin C depletion is associated with reduced work efficiency during submaximal exercise.

Body fat distribution and hemodynamic stress responses in premenopausal obese women: a preliminary study.

To examine the relationship between body fat distribution and hemodynamic stress responses, cardiovascular responses to a speech task and a forehead cold pressor task were evaluated with 24 premenopausal women classified a priori as either centrally or peripherally obese. Results showed that women with central adiposity exhibited greater stress-related increases in diastolic blood pressure and total peripheral resistance, whereas women with peripheral adiposity exhibited greater stress-related increases in cardiac output. Depression, self-consciousness, hostility, and mood scores did not explain significant variance in the stress response differences between regional adiposity groups. The findings suggest that central adiposity may increase the risk of cardiovascular disease in women at least in part by enhancing vascular responses to stress.

Social physique anxiety in postmenopausal women.

Social physique anxiety (SPA), the degree to which individuals become anxious when others observe their bodies, is an important concept for postmenopausal women because it may be directly related to their physical activity behavior. Women with high levels of social physique anxiety may not participate in health-enhancing physical activity. Therefore, the main purpose of this study was to examine SPA in postmenopausal women relative to leisure time physical activity (LTPA, activities such as exercise, recreation, and sports). Other factors, such as percent body fat, body fat distribution, age, and hormone replacement therapy status were also examined for their relationship to SPA. Women who expended < or = 500 kcal.wk-1 in LTPA had significantly higher SPA than women who expended > or = 2,000 kcal.wk-1, independent of percent body fat. Women with more than 37.5% body fat had significantly higher SPA than those with less than 37.5% body fat. Women with upper BFD (waist-to-hip ratio or WHR > 0.85) had higher SPA than women with lower BFD (WHR < 0.75). There were no differences in SPA relative to age or HRT status. It appears that a sedentary lifestyle, high percent body fat, and upper body fat distribution are associated with increased SPA in postmenopausal women, thus health promotion professionals should be aware of these concerns when developing physical activity interventions for postmenopausal women.

Energy expenditure estimates of the Caltrac accelerometer for running, race walking, and stepping.

OBJECTIVE: To examine the accuracy of the Caltrac accelerometer for estimating energy expenditure (EE) during three exercise modes. METHODS: A subset of 31 women (mean (SEM) age 22.6 (5) years) as selected from a training study comparing various physiological parameters during race walking, running, and stepping. Subjects each performed mode specific graded exercise tests to peak VO2. Regression equations for VO2 v heart rate (HR) were generated from each individual's test data. EE (kcal and kJ) was estimated for each VO2 value based on the respiratory exchange ratio, and kcal v HR regression equations were generated to predict EE from each subject's HR data (EE-HR). HR in the field was monitored by telemetry, and two Caltrac monitors, one set for EE and one to give counts, were attached to a belt over opposite hips. RESULTS: EE-HR was not significantly different across exercise modes. Caltrac overestimated EE (P < 0.01) in runners (14%) and walkers (19%) but underestimated EE in steppers by about 10% (P = 0.12). CONCLUSIONS: The Caltrac is a reliable instrument but it did not accurately distinguish EE in running, race walking, or stepping in a group of young women.

Assessment of lifetime patterns of dairy food intake and physical activity.

Patterns of nutrition and exercise throughout the life span may account for differences in health problems of aging. The purpose of this study was to develop and validate a simple life span history questionnaire of dairy food intake and to assess recalled levels of leisure time physical activity over the life span. Volunteers, 98 women and 49 men, completed two nutritional surveys (Criterion Questionnaire, ¿CRIQ¿ and Diary Food Index, ¿INDX¿) and a physical activity questionnaire (P-ACTQ) in a test re-test design. The INDX and P-ACTQ consisted of a one to four scale (low to high intake). Dairy food intake averaged 1.4 to 2.3 servings per day with no significant differences in current dairy food intake between decade age categories. When compared to their own recalled 20's decade, dairy food intake declined slightly with age, except for the 80-89 age group which showed an increased intake. Test retest reliability for the INDX was r = 0.64. Validity of the INDX compared to the CRIQ was r = 0.64. All groups showed a decrease in physical activity levels across the life span. The Dairy Food Index holds promise as a simple "global" assessment of dairy food intake for the study of lifetime trends in advancing our understanding of the role of lifetime habits in chronic "lifestyle" diseases.