A Randomized Controlled Trial of Two Different Macronutrient Profiles on Weight, Body Composition and Metabolic Parameters in Obese Adolescents Seeking Weight Loss

Objective

Adolescent obesity is difficult to treat and the optimal dietary pattern, particularly in relation to macronutrient composition, remains controversial. This study tested the effect of two structured diets with differing macronutrient composition versus control, on weight, body composition and metabolic parameters in obese adolescents.

Design

A randomized controlled trial conducted in a children’s hospital.

Methods

Eighty seven obese youth (means: age 13.6 years, BMI z-score 2.2, waist: height ratio 0.65, 69% female) completed a psychological preparedness program and were then randomized to a short term ‘structured modified carbohydrate’ (SMC, 35% carbohydrate; 30% protein; 35% fat, n = 37) or a ‘structured low fat’ (SLF, 55% carbohydrate; 20% protein; 25% fat, n = 36) or a wait listed control group (n = 14). Anthropometric, body composition and biochemical parameters were measured at randomization and after 12 weeks, and analyzed under the intention to treat principle using analysis of variance models.

Results

After 12 weeks, data was collected from 79 (91%) participants. BMI z-scores were significantly lower in both intervention groups compared to control after adjusting for baseline values, SLF vs. control, mean difference = -0.13 (95%CI = -0.18, -0.07), P<0.001; SMC vs. control, -0.14 (-0.19, -0.09), P<0.001, but there was no difference between the two intervention diet groups: SLF vs. SMC, 0.00 (-0.05, 0.04), P = 0.83.

Conclusions

Both dietary patterns resulted in similar changes in weight, body composition and metabolic improvements compared to control. The use of a structured eating system which allows flexibility but limited choices can assist in weight change and the rigid application of a low fat eating pattern is not exclusive in its efficacy.

Trial Registration

International Clinical Trials Registry ISRCTN49438757

Engaging men in weight loss: Experiences of men who participated in the male only SHED-IT pilot study

SUMMARY

Recruiting men to weight loss programs is notoriously difficult and little is known about the experiences of men who participate in weight loss programs. The aims of this paper were to report the perceptions and experiences of men who enrolled in the SHED-IT (Self-Help, Exercise, Diet and Information Technology) randomized controlled trial in the context of (1) what attracted them to the program, (2) their satisfaction with the program and its components, and (3) their suggestions for improvements to the program. The SHED-IT program exclusively targeted men and was developed to appeal to men. Individual semi-structured interviews were conducted with 18 overweight/obese (BMI between 25 and 37 kg/m(2)) men aged 18-60 years who were employed or enrolled at the University of Newcastle and who had been enrolled to the SHED-IT trial and randomly allocated to receive either the Internet intervention or basic weight-loss Information Only. Significant weight loss was achieved by both groups. A thematic analysis was undertaken applying the constant comparison method. Results indicated that lack of knowledge was a major weight loss barrier and men were attracted to a program that did not require extensive time commitments, was tailored for men and allowed inclusion of 'treat' food and drinks. Men were satisfied with both programs and valued the education about energy balance and the humour used to deliver simple messages. More face-to-face contact was a common suggestion for improvement. Our findings will inform future weight loss interventions for men and assist researchers and practitioners to engage men in weight loss.:

Systematic review of interventions in the management of overweight and obese children which include a dietary component

Background  The prevalence of overweight and obesity in children and adolescents is increasing at an alarming rate around the world and prevention has become a key public health objective. Treatment and management of those already overweight and obese must be aligned with the best available evidence on effectiveness, if the risk of obesity-related morbidity and mortality is yet be reduced. Diet plays a pivotal role in successful treatment of obesity but to date, there is limited evidence on which to base practice. Objectives  To identify and present the best available evidence on the optimal dietetic treatment and management of children and adolescent who are overweight or obese. Search strategy  Published English language literature was searched using the electronic databases CINAHL, MEDLINE, PRE-MEDLINE, DARE, COCHRANE, EMBASE, AUSTROM, Current Concepts and Dissertation Abstracts. The databases were limited to English Language from 1975 until 2003. Government reports from the UK, USA and Australian were also searched and a hand search performed for the Journal of the Dietitians Association of Australia, International Journal of Obesity and the Journal of Human Nutrition and Dietetics and the bibliographies of retrieved articles. Selection criteria  (i) Interventions that evaluated the effectiveness of nutrition or dietary interventions to treat or manage overweight and obesity; (ii) Children aged less than 18 years; and (iii) Participants were defined as overweight or obese by relative weight or a measure of body weight status, studies that reported body weight per se were excluded. Data collection and analysis  An experienced professional librarian searched the databases, and two trained research assistants independently identified studies for retrieval and assessed each article for inclusion. The included studies were critically appraised for methodological quality by two people independently. Data were extracted from the appropriate articles and when a discrepancy arose, a third party would arbitrate. Main results  There were 116 articles that met the inclusion criteria. While 49 articles described randomised controlled trials, they arose from 37 separate studies. There were 67 non-randomised trials. Meta-analyses were performed on eight studies that included both a dietary intervention component and an adequate control group and on four studies that had follow-up data. There was a high degree of heterogeneity between studies and this made comparisons between studies problematic. Interventions that include diet therapy generally result in significant weight loss, at least in the short term. Many studies were poorly designed and had no or only minimal follow up. The details of the dietary intervention were often inadequately described and dietary outcomes rarely reported, making repetition of the studies difficult. Reviewers' conclusions  There is an urgent need for high quality studies investigating the optimal dietary approach to management of paediatric overweight and obesity. These studies require adequate follow up to ascertain if weight loss can be sustained in the long term. Details of the dietary prescription, adherence to the dietary intervention and diet-specific outcomes need to be reported in order to inform best practice.

Timing and magnitude of C partitioning through a young loblolly pine (Pinus taeda L.) stand using 13C labeling and shade treatments

The dynamics of rapid changes in carbon (C) partitioning within forest ecosystems are not well understood, which limits improvement of mechanistic models of C cycling. Our objective was to inform model processes by describing relationships between C partitioning and accessible environmental or physiological measurements, with a special emphasis on short-term C flux through a forest ecosystem. We exposed eight 7-year-old loblolly pine (Pinus taeda L.) trees to air enriched with (13)CO(2) and then implemented adjacent light shade (LS) and heavy shade (HS) treatments in order to manipulate C uptake and flux. The impacts of shading on photosynthesis, plant water potential, sap flow, basal area growth, root growth and soil CO(2) efflux rate (CER) were assessed for each tree over a 3-week period. The progression of the (13)C label was concurrently tracked from the atmosphere through foliage, phloem, roots and surface soil CO(2) efflux. The HS treatment significantly reduced C uptake, sap flow, stem growth and fine root standing crop, and resulted in greater residual soil water content to 1 m depth. Soil CER was strongly correlated with sap flow on the previous day, but not the current day, with no apparent treatment effect on the relationship. Although there were apparent reductions in new C flux belowground, the HS treatment did not noticeably reduce the magnitude of belowground autotrophic and heterotrophic respiration based on surface soil CER, which was overwhelmingly driven by soil temperature and moisture. The (13)C label was immediately detected in foliage on label day (half-life = 0.5 day), progressed through phloem by Day 2 (half-life = 4.7 days), roots by Days 2-4, and subsequently was evident as respiratory release from soil which peaked between Days 3 and 6. The δ(13)C of soil CO(2) efflux was strongly correlated with phloem δ(13)C on the previous day, or 2 days earlier. While the (13)C label was readily tracked through the ecosystem, the fate of root C through respiratory, mycorrhizal or exudative release pathways was not assessed. These data detail the timing and relative magnitude of C flux through various components of a young pine stand in relation to environmental conditions.

The impact of a school garden and cooking program on boys' and girls' fruit and vegetable preferences, taste rating, and intake

The aim of this study was to examine gender differences in the impact of a school garden and nutrition curriculum on fruit and vegetable intake, willingness to taste, and taste ratings in 127 children (11 to 12 years, 54% boys) in regional New South Wales, Australia. Classes were assigned to wait-list control, nutrition education only (NE), or nutrition education plus garden (NE + G) groups. Carrot taste rating was the only vegetable for which there was a significant gender difference, with girls rating it more highly (p = .04). There were no significant gender differences in fruit and vegetable consumption or willingness to taste scores for any other vegetables. There was a group effect (p < .001) for overall willingness to taste, overall taste rating, and the taste rating of pea and broccoli (p < .001), tomato (p = .03), and lettuce (p = .02). In the post hoc analysis by gender, both boys and girls in NE + G and NE groups were more willing to taste vegetables compared with control boys and girls postintervention (p < .001, p = .02). Boys in the NE + G group were more willing to taste all vegetables overall compared with NE boys at posttest (p = .05) and this approached significance for girls (p = .07). For overall tasting scores, a group effect was seen in girls only (p = .05). No significant treatment-time effect was found for vegetable intake in either gender. Further research is needed to examine whether a school garden, with or without school curriculum components, can be used to optimize fruit and vegetable intakes, particularly in boys.

Parent diet modification, child activity, or both in obese children: an RCT

OBJECTIVES

Outcomes of childhood obesity interventions are rarely reported beyond 1 year. We hypothesized that the impact on the BMI z score from a child-centered physical-activity program in combination with a parent-centered dietary-modification program would be greater than either program conducted alone at 24 months' after baseline.

PARTICIPANTS AND METHODS

A total of 165 overweight prepubertal children (68 boys, aged 5.5-9.9 years, mean BMI z score: 2.8) were randomly assigned to either a child-centered physical-activity program, a parent-centered dietary-modification program, or both conducted together in an assessor-blinded 6-month intervention.

RESULTS

Using linear mixed models, all groups reduced their mean (95% confidence interval) BMI z score at 24 months from baseline (P < .001) (the activity and diet group: -0.24 [-0.35 to -0.13]; the diet-only group: -0.35 [-0.48 to -0.22]; activity-only group -0.19 [-0.30 to -0.07]). There was a significant group-by-time interaction (P = .04) with the activity + diet and the diet-only groups showing a greater reduction than the activity-only group. For waist z score and waist-to-height ratio, there was a significant time effect (P < .0001) at 24 months but no between-group differences (P > .05). Some metabolic outcomes improved at 24 months, although there were no between-group differences (P > .05).

CONCLUSIONS

A reduction in BMI z score was sustained at 24 months by treatment with either program combination. The greatest effects were achieved through inclusion of a parent-centered diet program, indicating the importance of targeting parents within treatment and the possibility of targeting them exclusively in treating obese prepubertal children.

12-month outcomes and process evaluation of the SHED-IT RCT: an internet-based weight loss program targeting men

This article reports the 12-month follow-up results and process evaluation of the SHED-IT (Self-Help, Exercise, and Diet using Information Technology) trial, an Internet-based weight loss program exclusively for men. Sixty-five overweight/obese male staff and students at the University of Newcastle (Callaghan, Australia) (mean (s.d.) age = 35.9 (11.1) years; BMI = 30.6 (2.8)) were randomly assigned to either (i) Internet group (n = 34) or (ii) Information only control group (n = 31). Both received one face-to-face information session and a program booklet. Internet group participants were instructed to use the study website for 3 months. Participants were assessed at baseline, 3-, 6-, and 12-month follow-up for weight, waist circumference, BMI, blood pressure, and resting heart rate. Retention at 3- and 12-months was 85% and 71%, respectively. Intention-to-treat (ITT) analysis using linear mixed models revealed significant and sustained weight loss of -5.3 kg (95% confidence interval (CI): -7.5, -3.0) at 12 months for the Internet group and -3.1 kg (95% CI: -5.4, -0.7) for the control group with no group difference. A significant time effect was found for all outcomes (P < 0.001). Per-protocol analysis revealed a significant group-by-time interaction for weight, waist circumference, BMI, and systolic blood pressure. Internet group compliers (who self-monitored as instructed) maintained greater weight loss at 12 months (-8.8 kg; 95% CI -11.8, -5.9) than noncompliers (-1.9 kg; 95% CI -4.8, 1.0) and controls (-3.0 kg; 95% CI -5.2, -0.9). Qualitative analysis by questionnaire and interview highlighted the acceptability and satisfaction with SHED-IT. Low-dose approaches to weight loss are feasible, acceptable, and can achieve clinically important weight loss in men after 1-year follow-up.

The SHED-IT community trial study protocol: a randomised controlled trial of weight loss programs for overweight and obese men

BACKGROUND

Obesity is a major cause of preventable death in Australia with prevalence increasing at an alarming rate. Of particular concern is that approximately 68% of men are overweight/obese, yet are notoriously difficult to engage in weight loss programs, despite being more susceptible than women to adverse weight-related outcomes. There is a need to develop and evaluate obesity treatment programs that target and appeal to men. The primary aim of this study is to evaluate the efficacy of two relatively low intensity weight loss programs developed specifically for men.

METHODS AND DESIGN

The study design is an assessor blinded, parallel-group randomised controlled trial that recruited 159 overweight and obese men in Newcastle, Australia. Inclusion criteria included: BMI 25-40 (kg/m2); no participation in other weight loss programs during the study; pass a health-screening questionnaire and pre-exercise risk assessment; available for assessment sessions; access to a computer with e-mail and Internet facilities; and own a mobile phone. Men were recruited to the SHED-IT (Self-Help, Exercise and Diet using Internet Technology) study via the media and emails sent to male dominated workplaces. Men were stratified by BMI category (overweight, obese class I, obese class II) and randomised to one of three groups: (1) SHED-IT Resources - provision of materials (DVD, handbooks, pedometer, tape measure) with embedded behaviour change strategies to support weight loss; (2) SHED-IT Online - same materials as SHED-IT Resources plus access to and instruction on how to use the study website; (3) Wait-list Control. The intervention programs are three months long with outcome measures taken by assessors blinded to group allocation at baseline, and 3- and 6-months post baseline. Outcome measures include: weight (primary outcome), % body fat, waist circumference, blood pressure, resting heart rate, objectively measured physical activity, self-reported dietary intake, sedentary behaviour, physical activity and dietary cognitions, sleepiness, quality of life, and perceived sexual health. Generalised linear mixed models will be used to assess all outcomes for the impact of group (Resources, Online, and Control), time (treated as categorical with levels baseline, 3-months and 6-months) and the group-by-time interaction. These three terms will form the base model. 'Intention-to-treat' analysis will include all randomised participants.

DISCUSSION

Our study will compare evidence-based and theoretically driven, low cost and easily disseminated strategies specifically targeting weight loss in men. The SHED-IT community trial will provide evidence to inform development and dissemination of sustainable strategies to reduce obesity in men.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry (ACTRN12610000699066).

Multi-site randomized controlled trial of a child-centered physical activity program, a parent-centered dietary-modification program, or both in overweight children: the HIKCUPS study

OBJECTIVE

To evaluate whether a child-centered physical activity program, combined with a parent-centered dietary program, was more efficacious than each treatment alone, in preventing unhealthy weight-gain in overweight children.

STUDY DESIGN

An assessor-blinded randomized controlled trial involving 165 overweight/obese 5.5- to 9.9- year-old children. Participants were randomly assigned to 1 of 3 interventions: a parent-centered dietary program (Diet); a child-centered physical activity program (Activity); or a combination of both (Diet+Activity). All groups received 10 weekly face-to-face sessions followed by 3 monthly relapse-prevention phone calls. Analysis was by intention-to-treat. The primary outcome was change in body mass index z-score at 6 and 12 months (n=114 and 106, respectively).

RESULTS

Body mass index z-scores were reduced at 12-months in all groups, with the Diet (mean [95% confidence interval]) (-0.39 [-0.51 to 0.27]) and Diet + Activity (-0.32, [-0.36, -0.23]) groups showing a greater reduction than the Activity group (-0.17 [-0.28, -0.06]) (P=.02). Changes in other outcomes (waist circumference and metabolic profile) were not statistically significant among groups.

CONCLUSION

Relative body weight decreased at 6 months and was sustained at 12 months through treatment with a child-centered physical activity program, a parent-centered dietary program, or both. The greatest effect was achieved when a parent-centered dietary component was included.

Exploring the mechanisms of weight loss in the SHED-IT intervention for overweight men: a mediation analysis

BACKGROUND

Statistical mediation analysis can be used to improve the design of obesity prevention and treatment programs by identifying the possible mechanisms through which an intervention achieved its effects. The aim of this study was to identify mediators of weight loss in an Internet-based weight-loss program specifically designed for overweight men.

METHODS

The Self-Help, Exercise and Diet using Information Technology (SHED-IT) program was a 3-month randomized controlled trial (Internet-based intervention group vs information only control group) that was implemented in 2007 with baseline and 6-month follow-up assessment of weight, physical activity and dietary behaviors. Intention-to-treat and per-protocol mediation analyses were conducted using a product-of-coefficients test.

RESULTS

Participants (N = 65) were overweight and obese male academic (n = 10) and non-academic (n = 27) staff and students (n = 28) from the University of Newcastle, Australia. Mean (SD) age = 35.9 (11.1) years and mean (SD) BMI = 30.6 (2.8). In the intention-to-treat analysis, both groups lost weight, but relative to the control group, the intervention did not have a statistically significant 'total effect' on weight, tau = -.507, p = .716 (95% CI = -3.277 to 2.263). In the per-protocol analysis, the intervention had a statistically significant 'total effect' on weight, tau = -4.487, p < .05 (95% CI = -8.208 to -.765). The intervention did not have a statistically significant effect on any of the hypothesized mediators and none of the behavioral variables mediated weight loss in the SHED-IT program. Although participants in the intervention group reduced their fat intake over the study period, the changes did not satisfy the criteria for mediation.

CONCLUSION

Few studies have examined the mediators of weight loss in obesity treatment interventions. While none of the hypothesized mediators satisfied the criteria for mediation in the current study, there was some evidence to suggest that overweight men in the SHED-IT intervention reduced their fat intake over the study period. Future obesity treatment and prevention programs should explore behavioral mediators of weight loss using appropriate statistical methods.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry No: ANZCTRN12607000481471.

Exploring the mechanisms of weight loss in the SHED-IT intervention for overweight men: a mediation analysis

BACKGROUND

Statistical mediation analysis can be used to improve the design of obesity prevention and treatment programs by identifying the possible mechanisms through which an intervention achieved its effects. The aim of this study was to identify mediators of weight loss in an Internet-based weight-loss program specifically designed for overweight men.

METHODS

The Self-Help, Exercise and Diet using Information Technology (SHED-IT) program was a 3-month randomized controlled trial (Internet-based intervention group vs information only control group) that was implemented in 2007 with baseline and 6-month follow-up assessment of weight, physical activity and dietary behaviors. Intention-to-treat and per-protocol mediation analyses were conducted using a product-of-coefficients test.

RESULTS

Participants (N = 65) were overweight and obese male academic (n = 10) and non-academic (n = 27) staff and students (n = 28) from the University of Newcastle, Australia. Mean (SD) age = 35.9 (11.1) years and mean (SD) BMI = 30.6 (2.8). In the intention-to-treat analysis, both groups lost weight, but relative to the control group, the intervention did not have a statistically significant 'total effect' on weight, tau = -.507, p = .716 (95% CI = -3.277 to 2.263). In the per-protocol analysis, the intervention had a statistically significant 'total effect' on weight, tau = -4.487, p < .05 (95% CI = -8.208 to -.765). The intervention did not have a statistically significant effect on any of the hypothesized mediators and none of the behavioral variables mediated weight loss in the SHED-IT program. Although participants in the intervention group reduced their fat intake over the study period, the changes did not satisfy the criteria for mediation.

CONCLUSION

Few studies have examined the mediators of weight loss in obesity treatment interventions. While none of the hypothesized mediators satisfied the criteria for mediation in the current study, there was some evidence to suggest that overweight men in the SHED-IT intervention reduced their fat intake over the study period. Future obesity treatment and prevention programs should explore behavioral mediators of weight loss using appropriate statistical methods.

TRIAL REGISTRATION

Australian New Zealand Clinical Trials Registry No: ANZCTRN12607000481471.

The SHED-IT randomized controlled trial: evaluation of an Internet-based weight-loss program for men

The aim of this study was to evaluate the efficacy of an Internet-based weight-loss program for men in an assessor blinded randomized controlled trial. In total, 65 overweight/obese male staff and students at the University of Newcastle (mean (s.d.) age = 35.9 (11.1) years; BMI = 30.6 (2.8)) were randomly assigned to either (i) Internet group (n = 34) or (ii) control group (information only) (n = 31). Both groups received one face-to-face information session and a program booklet. Internet group participants used the study website to self-monitor diet and activity with feedback provided based on participants' online entries on seven occasions over 3 months. Participants were assessed at baseline, 3-, and 6-month follow-up for weight, waist circumference, BMI, blood pressure, resting heart rate, objectively measured physical activity, and self-reported total daily kilojoules. Intention-to-treat analysis revealed significant weight loss of 5.3 kg (95% confidence interval (CI): -7.3, -3.3) at 6 months for the Internet group and 3.5 kg (95% CI: -5.5, -1.4) for the control group. A significant time effect was found for all outcomes but no between-group differences. Per-protocol analysis revealed a significant group-by-time interaction (P < 0.001), with compliers losing more weight at 6 months (-9.1 kg; 95% CI -11.8, -6.5) than noncompliers (-2.7 kg; 95% CI -5.3, -0.01) and the control group (-4.2 kg; 95% CI -6.2, -2.2). Simple weight-loss interventions can be effective in achieving statistically and clinically significant weight loss in men. The Internet is a feasible and effective medium for weight loss in men but strategies need to be explored to improve engagement in online programs.

Process Evaluation of the Hunter Illawarra Kids Challenge Using Parent Support Study: A Multisite Randomized Controlled Trial for the Management of Child Obesity

The purposes of this article are to (a) outline findings from secondary or process outcome data of the Hunter Illawarra Kids Challenge Using Parent Support (HIKCUPS) study and (b) inform the design and development of future research interventions and practice in the management of child obesity. Data were collected by means of facilitator evaluations, independent session observation, attendance records, and parent questionnaires. Internal validity and reliability of the program delivery were high. All parents reported positive changes in their children as a result of the physical activity program, the dietary modification program, or both. Most participants completed the home activities, but more than half reported that finding time to do them was problematic. Facilitator review indicated that future programs should specifically cater to children of similar age or same sex, allow adequate time for explanation of complex nutritional concepts, and use intrinsic motivators for participants. Recommendations for future interventions, specifically the implementation of subsequent HIKCUPS or other multisite effectiveness studies, are detailed.

Validation of overweight children's fruit and vegetable intake using plasma carotenoids

Assessing dietary intake in children is difficult and limited validated tools exist. Plasma carotenoids are nutritional biomarkers of fruit and vegetable intake and therefore suitable to validate reported dietary intakes. The aim of this study was to examine the comparative validity of a food frequency questionnaire (FFQ), completed by parents reporting child fruit and vegetable intake compared to plasma carotenoid concentrations. A sample of children aged 5-12 years (n = 93) from a range of weight categories were assessed. Dietary intake was measured using a 137-item semi-quantitative FFQ. Plasma carotenoids were measured using reverse phase high-performance liquid chromatography. Pearson correlation coefficients between reported dietary intake of carotenoids and plasma carotenoid concentrations were strongest after adjustment for BMI (beta-carotene (r = 0.56, P < 0.05), alpha-carotene (r = 0.51, P < 0.001), cryptoxanthin (r = 0.32, P < 0.001)). Significantly lower levels (P < 0.05) of all plasma carotenoids, except lutein, were found among overweight and obese children when compared to healthy weight children. Parental report of children's carotenoid intakes, using a FFQ can be used to provide a relative validation of fruit and vegetable intake. The lower plasma carotenoid concentrations found in overweight and obese children requires further investigation.

Randomised controlled trials in overweight children: practicalities and realities

AIM

To highlight and discuss the practical aspects of conducting high quality, randomised controlled trials (RCTs) with overweight and obese children and their families.

CONTENT

Realistic considerations and suggestions for researchers arising from the experiences of three Australian interventions in overweight/obese children are highlighted. The practical implications of key issues arising during this type of RCT include study design, obtaining ethical approval, choice of outcome measures, recruitment, working with families, impact and process evaluation, retention strategies, managing multi-site trials and data management.

CONCLUSION

Interventions for overweight children and their families are challenging. Although there were some differences in the design and outcome measures among the three studies, there were many similarities. Multi-site trials, although more expensive than single-site trials, are advantageous in increasing sample size and external validity. Collectively we have developed strategies to address key problems in conducting RCTs, including the common challenges of recruitment, retention and working with families.

The HIKCUPS trial: a multi-site randomized controlled trial of a combined physical activity skill-development and dietary modification program in overweight and obese children

Background

Childhood obesity is one of the most pressing health issues of our time. Key health organizations have recommended research be conducted on the effectiveness of well-designed interventions to combat childhood obesity that can be translated into a variety of settings. This paper describes the design and methods used in the Hunter Illawarra Kids Challenge Using Parent Support (HIKCUPS) trial, an ongoing multi-site randomized controlled trial, in overweight/obese children comparing the efficacy of three interventions: 1) a parent-centered dietary modification program; 2) a child-centered physical activity skill-development program; and 3) a program combining both 1 and 2 above.

Methods/Design

Each intervention consists of three components: i) 10-weekly face-to-face group sessions; ii) a weekly homework component, completed between each face-to-face session and iii) three telephone calls at monthly intervals following completion of the 10-week program. Details of the programs' methodological aspects of recruitment, randomization and statistical analyses are described here a priori.

Discussion

Importantly this paper describes how HIKCUPS addresses some of the short falls in the current literature pertaining to the efficacy of child obesity interventions.

The HIKCUPS trial is funded by the National Medical Research Council, Australia.

The HIKCUPS trial: a multi-site randomized controlled trial of a combined physical activity skill-development and dietary modification program in overweight and obese children

BACKGROUND

Childhood obesity is one of the most pressing health issues of our time. Key health organizations have recommended research be conducted on the effectiveness of well-designed interventions to combat childhood obesity that can be translated into a variety of settings. This paper describes the design and methods used in the Hunter Illawarra Kids Challenge Using Parent Support (HIKCUPS) trial, an ongoing multi-site randomized controlled trial, in overweight/obese children comparing the efficacy of three interventions: 1) a parent-centered dietary modification program; 2) a child-centered physical activity skill-development program; and 3) a program combining both 1 and 2 above.

METHODS/DESIGN

Each intervention consists of three components: i) 10-weekly face-to-face group sessions; ii) a weekly homework component, completed between each face-to-face session and iii) three telephone calls at monthly intervals following completion of the 10-week program. Details of the programs' methodological aspects of recruitment, randomization and statistical analyses are described here a priori.

DISCUSSION

Importantly this paper describes how HIKCUPS addresses some of the short falls in the current literature pertaining to the efficacy of child obesity interventions. The HIKCUPS trial is funded by the National Medical Research Council, Australia.

Systematic review of interventions in the management of overweight and obese children which include a dietary component

BACKGROUND

The prevalence of overweight and obesity in children and adolescents is increasing at an alarming rate around the world and prevention has become a key public health objective. Treatment and management of those already overweight and obese must be aligned with the best available evidence on effectiveness, if the risk of obesity-related morbidity and mortality is yet be reduced. Diet plays a pivotal role in successful treatment of obesity but to date, there is limited evidence on which to base practice.

OBJECTIVES

To identify and present the best available evidence on the optimal dietetic treatment and management of children and adolescent who are overweight or obese.

SEARCH STRATEGY

Published English language literature was searched using the electronic databases CINAHL, MEDLINE, PRE-MEDLINE, DARE, COCHRANE, EMBASE, AUSTROM, Current Concepts and Dissertation Abstracts. The databases were limited to English Language from 1975 until 2003. Government reports from the UK, USA and Australian were also searched and a hand search performed for the Journal of the Dietitians Association of Australia, International Journal of Obesity and the Journal of Human Nutrition and Dietetics and the bibliographies of retrieved articles.

SELECTION CRITERIA

(i) Interventions that evaluated the effectiveness of nutrition or dietary interventions to treat or manage overweight and obesity; (ii) Children aged less than 18 years; and (iii) Participants were defined as overweight or obese by relative weight or a measure of body weight status, studies that reported body weight per se were excluded.

DATA COLLECTION AND ANALYSIS

An experienced professional librarian searched the databases, and two trained research assistants independently identified studies for retrieval and assessed each article for inclusion. The included studies were critically appraised for methodological quality by two people independently. Data were extracted from the appropriate articles and when a discrepancy arose, a third party would arbitrate.

MAIN RESULTS

There were 116 articles that met the inclusion criteria. While 49 articles described randomised controlled trials, they arose from 37 separate studies. There were 67 non-randomised trials. Meta-analyses were performed on eight studies that included both a dietary intervention component and an adequate control group and on four studies that had follow-up data. There was a high degree of heterogeneity between studies and this made comparisons between studies problematic. Interventions that include diet therapy generally result in significant weight loss, at least in the short term. Many studies were poorly designed and had no or only minimal follow up. The details of the dietary intervention were often inadequately described and dietary outcomes rarely reported, making repetition of the studies difficult.

REVIEWERS' CONCLUSIONS

There is an urgent need for high quality studies investigating the optimal dietary approach to management of paediatric overweight and obesity. These studies require adequate follow up to ascertain if weight loss can be sustained in the long term. Details of the dietary prescription, adherence to the dietary intervention and diet-specific outcomes need to be reported in order to inform best practice.

Lack of evidence on diets for obesity for children: a systematic review

BACKGROUND

The prevalence of obesity has increased rapidly in most developed countries in the last decades, and this rise is now spreading to developing countries. Childhood obesity is also increasing. The UK government has set a target to halt the rise in childhood obesity by 2010. Dietary recommendations are a central component of any comprehensive weight-loss programme. A low-fat energy-restricted diet is the conventional therapy for obesity, but alternative dietary interventions have been proposed in recent years.

METHODS

We conducted a systematic review to assess dietary intervention studies designed to reduce weight in childhood and adolescence. The studies included overweight or obese children or adolescents in which there was a comparison group and change in body weight or BMI was reported.

RESULTS

We identified only nine such studies, seven of which were randomized. Six were conducted in the USA, two in Cuba, and one in France. Low-carbohydrate and low-glycaemic-index diets appeared to be at least as effective as energy-restricted low-fat diets for short-term weight loss, but most studies were too small to be informative, and none provided evidence on long-term weight control.

CONCLUSIONS

There is a marked mismatch between the public health importance of childhood obesity and the number and quality of the studies conducted so far to assess dietary interventions for weight reduction in childhood and adolescence, and little evidence to support the current recommendation of a low-fat energy-restricted diet. There is an urgent need for well-designed intervention studies of the long-term effectiveness of alternative diets to provide a basis for evidence-based recommendations.

Dynamics of water transport and storage in conifers studied with deuterium and heat tracing techniques

The volume and complexity of their vascular systems make the dynamics of long-distance water transport in large trees difficult to study. We used heat and deuterated water (D2)) as tracers to characterize whole-tree water transport and storage properties in individual trees belonging to the coniferous species Pseudotsuga menziesii (Mirb.) Franco and Tsuga heterophylla (Raf.) Sarg. The trees used in this study spanned a broad range of height (13.5-58 m) and diameter (0.14-1.43 m). Sap flow was monitored continuously with heat dissipation probes near the base of the trunk prior to, during and following injection of D2O. The transit time for D2O transport from the base of the trunk to the upper crown and the tracer residence time were determined by measuring hydrogen isotope ratios in water extracted from leaves sampled at regular intervals. Transit times for arrival of D2O in the upper crown ranged from 2.5 to 21 d and residence times ranged from 36 to 79 d. Estimates of maximum sap velocity derived from tracer transit times and path length ranged from 2.4 to 5.4 m d(-1). Tracer residence time and half-life increased as tree diameter increased, independent of species. Species-independent scaling of tracer velocity with sapwood-specific conductivity was also observed. When data from this study were combined with similar data from an earlier study of four tropical angiosperm trees, species-independent scaling of tracer velocity and residence time with sapwood hydraulic capacitance was observed. Sapwood capacitance is an intrinsic tissue-level property that appears to govern whole-tree water transport in a similar manner among both tracheid- and vessel-bearing species.

Converging patterns of uptake and hydraulic redistribution of soil water in contrasting woody vegetation types

We used concurrent measurements of soil water content and soil water potential (Psi(soil)) to assess the effects of Psi(soil) on uptake and hydraulic redistribution (HR) of soil water by roots during seasonal drought cycles at six sites characterized by differences in the types and amounts of woody vegetation and in climate. The six sites included a semi-arid old-growth ponderosa pine (Pinus ponderosa Dougl. ex P. Laws & C. Laws) forest, a moist old-growth Douglas-fir (Pseudotsuga menziesii (Mirb.) Franco) forest, a 24-year-old Douglas-fir forest and three Brazilian savanna sites differing in tree density. At all of the sites, HR was confined largely to the upper 60 cm of soil. There was a common threshold relationship between the relative magnitude of HR and Psi(soil) among the six study sites. Below a threshold Psi(soil) of about -0.4 MPa, overnight recharge of soil water storage increased sharply, and reached a maximum value of 80-90% over a range of Psi(soil) from ~ -1.2 to -1.5 MPa. Although amounts of water hydraulically redistributed to the upper 60 cm of soil were relatively small (0 to 0.4 mm day(-1)), they greatly reduced the rates of seasonal decline in Psi(soil). The effectiveness of HR in delaying soil drying diminished with increasing sapwood area per ground area. The relationship between soil water utilization and Psi(soil) in the 20-60-cm layer was nearly identical for all six sites. Soil water utilization varied with a surrogate measure of rhizosphere conductance in a similar manner at all six sites. The similarities in relationships between Psi(soil) and HR, soil water utilization and relative rhizosphere conductance among the six sites, suggests that, despite probable differences in maximum rooting depth and density, there was a convergence in biophysical controls on soil water utilization and redistribution in the upper soil layers where the density of finer roots is greatest.

Native root xylem embolism and stomatal closure in stands of Douglas-fir and ponderosa pine: mitigation by hydraulic redistribution

Hydraulic redistribution (HR), the passive movement of water via roots from moist to drier portions of the soil, occurs in many ecosystems, influencing both plant and ecosystem-water use. We examined the effects of HR on root hydraulic functioning during drought in young and old-growth Douglas-fir [ Pseudotsuga menziesii (Mirb.) Franco] and ponderosa pine ( Pinus ponderosa Dougl. Ex Laws) trees growing in four sites. During the 2002 growing season, in situ xylem embolism, water deficit and xylem vulnerability to embolism were measured on medium roots (2-4-mm diameter) collected at 20-30 cm depth. Soil water content and water potentials were monitored concurrently to determine the extent of HR. Additionally, the water potential and stomatal conductance ( g(s)) of upper canopy leaves were measured throughout the growing season. In the site with young Douglas-fir trees, root embolism increased from 20 to 55 percent loss of conductivity (PLC) as the dry season progressed. In young ponderosa pine, root embolism increased from 45 to 75 PLC. In contrast, roots of old-growth Douglas-fir and ponderosa pine trees never experienced more than 30 and 40 PLC, respectively. HR kept soil water potential at 20-30 cm depth above -0.5 MPa in the old-growth Douglas-fir site and -1.8 MPa in the old-growth ponderosa pine site, which significantly reduced loss of shallow root function. In the young ponderosa pine stand, where little HR occurred, the water potential in the upper soil layers fell to about -2.8 MPa, which severely impaired root functioning and limited recovery when the fall rains returned. In both species, daily maximum g(s) decreased linearly with increasing root PLC, suggesting that root xylem embolism acted in concert with stomata to limit water loss, thereby maintaining minimum leaf water potential above critical values. HR appears to be an important mechanism for maintaining shallow root function during drought and preventing total stomatal closure.

Contrasting effects oft10,c12- andc9,t11-conjugated linoleic acid isomers on the fatty acid profiles of mouse liver lipids

The purpose of this study was to examine the effects of two purified isomers of CLA (c9,t11-CLA and t10,c12-CLA) on the weights and FA compositions of hepatic TG, phospholipids, cholesterol esters, and FFA. Eight-week-old female mice (n = 6/group) were fed either a control diet or diets supplemented with 0.5% c9,t11-CLA or t10,c12-CLA isomers for 8 wk. Weights of liver total lipids and those of individual lipid fractions did not differ between the control and the c9,t11-CLA groups. Livers from animals fed the t10, c12-CLA diet contained four times more lipids than those of the control group; this was mainly due to an increase in the TG fractions (fivefold), but cholesterol (threefold), cholesterol esters (threefold), and FFA (twofold) were also significantly increased. Although c9,t11-CLA did not significantly alter the weights of liver lipids when compared with the control group, its intake was associated with significant reductions in the weight percentage (wt% of total FAME) of 18:1n-9 and 18:1n-7 in the TG fraction and with significant increases in the weight percentage of 18:2n-6 in the TG, cholesterol ester, and phospholipid fractions. On the other hand, t10,c12-CLA intake was linked with a significant increase in the weight percentage of 18:1n-9 and a decrease in that of 18:2n-6 in all lipid fractions. These changes may be the result of alterations in the activity of delta9-desaturase (stearoyl CoA desaturase) and the enzymes involved in the metabolism of 18:2n-6. Thus, the two isomers differed not only in their effects on the weights of total liver lipids and lipid fractions but also on the FA profile of the lipid fractions.

Evaluation of a pilot school programme aimed at the prevention of obesity in children

This paper describes the development, implementation and evaluation of a school- and family-based intervention to prevent obesity in children aged 5-7 years. In addition, the efficacy of three different intervention programmes was compared. Children aged 5-7 years (n=213) were recruited from three primary schools in Oxford and randomly allocated to a control group or one of three intervention groups: nutrition group, physical activity group, and combined nutrition and physical activity group. The setting for the interventions was lunchtime clubs, where an interactive and age-appropriate nutrition and/or physical activity curriculum was delivered. The intervention lasted for 20 weeks over four school terms (approximately 14 months). Children's growth, nutrition knowledge, diet and physical activity were assessed at baseline and at the end of the intervention. Significant improvements in nutrition knowledge were seen in all children (p<0.01) between baseline and post-intervention, and results were highly significant in the nutrition and combined group (p<0.001). Overall, fruit and vegetable intake increased significantly (p<0.01 and <0.05, respectively), with changes seen in fruit consumption in the nutrition group (p<0.05) and the control group (p<0.05) in particular. No significant changes in the rates of overweight and obesity were seen as a result of the intervention. Gender differences were not detected in the majority of assessments and there was no clear effect of programme type per se. This pilot study has demonstrated that school may be a suitable setting for the promotion of healthy lifestyles in children, but requires replication in other social settings. Future initiatives should be long-lasting, multi-faceted and sustainable, involving all children in a school, and should target the whole environment and be behaviourally focused. The ultimate goal of any such programme is to lead to positive behaviour change which will have a beneficial effect on long-term health. Successful targeting of the family remains a challenge to such interventions.

Low glycemic index breakfasts and reduced food intake in preadolescent children

OBJECTIVE

Recent reports have suggested that a low glycemic index (GI) diet may have a role in the management of obesity through its ability to increase the satiety value of food and modulate appetite. To date, no long-term clinical trials have examined the effect of dietary GI on body weight regulation. The majority of evidence comes from single-day studies, most of which have been conducted in adults. The purpose of this study was to investigate the effect of 3 test breakfasts-low-GI, low-GI with 10% added sucrose, and high-GI-on ad libitum lunch intake, appetite, and satiety and to compare these with baseline values when habitual breakfast was consumed.

METHODS

A 3-way crossover study using block randomization of breakfast type was conducted in a school that already ran a breakfast club. A total of 37 children aged 9 to 12 years (15 boys and 22 girls) completed the study. The proportion of nonoverweight to overweight/obese children was 70:30. Children were divided into 5 groups, and a rolling program was devised whereby, week by week, each group would randomly receive 1 of 3 test breakfasts for 3 consecutive days, with a minimum of 5 weeks between the test breakfasts. Participants acted as their own control. The 3 test breakfasts were devised to match the energy and nutritional content of an individual's habitual breakfast as far as possible. All test breakfasts were composed of fruit juice, cereal, and milk with/without bread and margarine; foods with an appropriate GI value were selected. After each test breakfast, children were instructed not to eat or drink anything until lunchtime, except water and a small serving of fruit supplying approximately 10 g of carbohydrate, which was provided. Breakfast palatability, satiation after breakfast, and satiety before lunch were measured using rating scales based on previously used tools. Lunch was a buffet-style meal, and children were allowed free access to a range of foods. Lunch was served in the school hall where the rest of the schoolchildren were eating. Food intake at lunch was unobtrusively observed and recorded. Leftovers and food swapping were recorded, and plate waste was estimated. Lunch intakes were analyzed using a multilevel regression model for repeated measures data. The likelihood ratio statistic was used to determine whether the type of breakfast eaten had a significant effect on lunch intake after allowing for sex and weight status.

RESULTS

The type of breakfast eaten had a statistically significant effect on mean energy intake at lunchtime: lunch intake was lower after low-GI and low-GI with added sucrose breakfasts compared with lunch intake after high-GI and habitual breakfasts (which were high-GI). Overweight and sex did not have a significant effect on lunch intake. Pairwise comparisons among the 3 types of test breakfasts and between each test breakfast and habitual breakfast were made. Lunch intake after the high-GI breakfast was significantly higher than after the low-GI breakfast and low-GI breakfast with added sucrose. The details of the pairwise comparisons were as follows: high-GI versus low-GI = 145 +/- 54 kcal; high-GI versus low-GI plus sucrose = 119 +/- 53 kcal; low-GI plus sucrose versus low-GI = 27 +/- 54 kcal. Lunch intake after the low-GI breakfast and the low-GI breakfast with added sucrose was significantly lower than after the habitual breakfast. The details of the pairwise comparisons were as follows: low-GI versus habitual = -109 +/- 75 kcal; low-GI plus sucrose versus habitual = -83 +/- 75 kcal; high-GI versus habitual = 36 +/- 75 kcal. There were no significant differences between the test breakfasts in immediate satiation. The high-GI breakfasts were rated to be more palatable than the low-GI breakfasts. At lunchtime, hunger ratings were greater after the high-GI breakfast compared with the other 2 test breakfasts on 2 of the 3 experimental days. Prelunch satiety scales were inversely related to subsequent food intake.

CONCLUSIONS

These results suggest that low-GI foods eaten at breakfast have a significant impact on food intake at lunch. This is the first study to observe such an effect in a group of normal and overweight children and adds to the growing body of evidence that low-GI foods may have an important role in weight control and obesity management. The potentially confounding effect of differences in the macronutrient and dietary fiber content of the test breakfasts warrants additional study. In addition, the impact of GI on food intake and body weight regulation in the long term needs to be investigated.

Trans-10,cis-12 CLA increases liver and decreases adipose tissue lipids in mice: possible roles of specific lipid metabolism genes

Although consumption of CLA mixtures has been associated with several health effects, less is known about the actions of specific CLA isomers. There is evidence that the t10,c12-CLA isomer is associated with alterations in body and organ weights in animals fed CLA, but the mechanisms leading to these changes are unclear. The purpose of this study was to determine the effects of two commonly occurring isomers of CLA on body composition and the transcription of genes associated with lipid metabolism. Eight-week-old female mice (n = 11 or 12/group) were fed either a control diet or diets supplemented with 0.5% c9,t11-CLA or t10,c12-CLA isomers or 0.2% of the peroxisome proliferator-activated receptor alpha (PPARalpha) agonist fenofibrate for 8 wk. Body and retroperitoneal adipose tissue weights were significantly lower (6-10 and 50%, respectively), and liver weights were significantly greater (100%) in the t10,c12-CLA and the fenofibrate groups compared with those in the control group; body and tissue weights in the c9,t11-CLA group did not differ from those in the control group. Livers from animals in the t10,c12-CLA group contained five times more lipids than in the control group, whereas the lipid content of the fenofibrate group did not differ from that in the control group. Although fenofibrate increased the mRNA for PPARalpha, t10,c12-CLA decreased it. These results suggest that PPARalpha did not mediate the effects of t10,c12-CLA on body composition. The CLA isomers and fenofibrate altered mRNA levels for several proteins involved in lipid metabolism, but the most striking difference was the reduction of mRNA for leptin and adiponectin in the t10,c12-CLA group. These initial results suggest that changes associated with energy homeostasis and insulin action may mediate the effects of t10,c12-CLA on lipid metabolism.

How well do children aged 5-7 years recall food eaten at school lunch?

OBJECTIVE

This study aimed to determine the accuracy with which children aged 5 to 7 years were able to report the food eaten at a school lunch.

SUBJECTS/SETTING

Two hundred and three children (103 boys, 100 girls) aged 5-7 years were recruited from three primary schools in Oxford.

DESIGN

Trained investigators made observational records of the school dinner and packed lunch intakes of four or five children per session. Children were interviewed within two hours of finishing the lunchtime meal and asked to provide a free recall of their meal. When the child had completed the recall, non-directive prompts were used to assess if the child was able to remember anything else. Foods recalled were classified as matches (recalled food agreed with observation), omissions (failed to report a food observed) or phantoms (recalled food was not observed).

RESULTS

The percentage of accurate recall was significantly higher (P<0.01) in children eating packed lunch (mean 70 +/- 29%) than in children consuming school dinners (mean 58 +/- 27% ). This difference may have been due to increased familiarity of foods in packed lunches. Leftovers were not readily reported in this age group. Prompts and cues enhanced recall by all children.

CONCLUSIONS

This study indicated that there was a wide range in the ability of children aged 5-7 years to recall intake from a packed lunch and/or school dinner. This dietary assessment method is unlikely to be suitable at an individual level. Investigators using dietary recall to estimate food intake in children aged 5-7 years need to be aware of the limitations of this method.

Similar effects of c9,t11-CLA and t10,c12-CLA on immune cell functions in mice

Published results regarding the effects of CLA on immune cell functions have ranged from stimulation to inhibition. In those studies, a mixture of CLA isomers were used, and food intake was not controlled. We have examined whether the discrepancies in the results of earlier studies may be due to the lack of controlled feeding and whether the two isomers of CLA may differ in their effects on immune cell functions. Three groups of C57BL/6 female mice were fed either a control, c9,t11-CLA-, or t10,c12-CLA (0.5 wt%)-supplemented diet, 5 g/d, for 56 d. At the end of the study, the number of immune cells in spleens, bone marrows, or in circulation; proliferation of splenocytes in response to T and B cell mitogens; and prostaglandin secretion in vitro did not differ among the three groups. Both CLA isomers significantly increased in vitro tumor necrosis factor alpha and interleukin (IL)-6 secretion and decreased IL-4 secretion by splenocytes compared to those in the control group. Thus, the two CLA isomers had similar effects on all response variables tested. The discrepancies among the results from previous studies did not seem to be caused by the differences in the isomer composition of CLA used.

Treadmill exercise training blunts suppression of splenic natural killer cell cytolysis after footshock

This study extended to treadmill exercise training our prior report (Dishman RK, Warren JM, Youngstedt SD, Yoo H, Bunnell BN, Mougey EH, Meyerhoff JL, Jaso-Friedmann L, and Evans DL. J Appl Physiol 78: 1547-1554, 1995) that activity wheel running abolished the suppression of footshock-induced natural killer (NK) cell cytolysis. Twenty-four male Fischer 344 rats were assigned to one of three groups (n = 8, all groups): 1) a home-cage control group, 2) a sedentary treatment group, or 3) a treadmill-running group (0 degrees incline, 25 m/min, 35 min/day, 6 days/wk). After 6 wk, the treadmill and sedentary groups received 2 days of footshock. Splenic NK cytotoxicity was determined by standard 4-h (51)Cr release assay. Percentages of lymphocytes were determined by flow cytometry. Plasma levels of ACTH, corticosterone, and prolactin concentration were measured by radioimmunoassay. After footshock, percentage of lysis relative to home-cage controls was 40% and 80% for sedentary and treadmill-trained animals, respectively (P < 0.05). Our results indicate that the protective effect of chronic exercise on innate cellular immunity in the Fischer 344 male rat is not restricted to activity wheel running, nor is it explained by elevations in basal NK activity, increased percentages of splenic NK and cytotoxic T cells, or increased plasma levels of ACTH, corticosterone, and prolactin.

Characteristics of the muscularis mucosae in the acid-secreting region of the rabbit stomach

It has been suggested that muscularis mucosae excitation may augment gastric acid secretion, implying that this muscle should contract to secretagogues or stimulation of its motor innervation. The aim of this study was to characterize in vitro the responses of the muscularis mucosae in the rabbit gastric corpus to substances that modulate acid release and to intrinsic nerve stimulation. Muscularis mucosae from both fundic and antral ends of the corpus had identical mechanical properties, contracted to ACh, ADP, ATP, and histamine but relaxed to vasoactive intestinal polypeptide. Fundic but not antral muscularis mucosae contracted to bombesin and PGE2 and PGF2alpha, whereas adenosine, AMP, CCK, gastrin, secretin, and somatostatin were without effect on any preparation. In both regions electrical field stimulation evoked TTX-sensitive responses consisting of an atropine-resistant contraction followed by an NG-nitro-L-arginine methyl ester- and indomethacin-resistant relaxation. It is concluded from the regional variability in the pharmacological properties of the gastric muscularis mucosae that if its motor activity is linked to acid secretion this would be achieved by a neurally mediated relaxation rather than a paracrine- and/or endocrine-induced alteration in tone.

Activity-wheel running attenuates suppression of natural killer cell activity after footshock

We studied whether voluntary running in an activity wheel moderates splenic natural killer (NK) cell cytotoxicity after footshock. Young (50-day) male Fischer 344 rats were randomly assigned to 1) sedentary (n = 16) or 2) activity-wheel (n = 16) groups that each received controllable or uncontrollable footshock on 2 consecutive days or 3) a sedentary home-cage control group (n = 8). Spleens and trunk blood were collected 30 min after the second footshock session. Cytotoxicity was determined by a standard 4-h 51Cr release assay. Percentages of OX6+ (B), OX8+ [T suppressor/cytotoxic (Ts/c)], W3/25+ (T helper), Thy-1.1 (Pan T cell marker), and 5C6+ (NK) cells were determined by flow cytometry. Plasma adrenocorticotropic hormone, corticosterone, and prolactin concentrations were measured by radioimmunoassay as modulators of NK activity. Percentage of specific lysis after footshock was approximately 52% of control values for sedentary animals compared with approximately 96% of control values for activity-wheel animals. The groups did not differ in percentages of NK or Ts/c cells. We conclude that voluntary activity-wheel running protects against the suppression of splenic NK activity induced by footshock. This protective effect of wheel running is not explained by an elevation in baseline NK activity; increased percentages of splenic NK or Ts/c cells; or plasma levels of adrenocorticotropic hormone, corticosterone, and prolactin.

Rationing health care resources. Is the quality-adjusted life-year a helpful guide?

The quality-adjusted life-year, an economic tool for allocating health care resources, lets researchers compare the cost-effectiveness of different therapies for virtually any disease. It purports to describe quantity of life, with an adjustment for quality of life, as a function of financial cost. Its goal is to maximize health care efficiency, but its methodology does not adequately meet the needs of older patients.

Pulmonary function after laparoscopic cholecystectomy

BACKGROUND

The purpose of this study was to prospectively compare the effect of laparoscopic cholecystectomy (LC) versus open cholecystectomy (OC) on postoperative pulmonary function.

METHODS

Forty consecutive patients (20 in each group) who were evenly matched in terms of pulmonary risk factors were assigned to either elective LC or OC. Pulmonary function studies, oxygen saturation, and chest radiography were performed on both groups before and after the operation until baseline levels were reached. Narcotic requirements and pulmonary complications were compared. The t test, ANOVA, and chi-squared analysis were used.

RESULTS

Compared to the patients who underwent OC, patients who underwent LC had a significant reduction in postoperative pulmonary impairment (30% to 38%) in all areas studied including forced vital capacity; forced expiratory volume in 1 second; forced expiratory flow, mid-expiratory phase; maximum forced expiratory flow; maximum voluntary ventilation; total lung capacity; and oxygen saturation. Pulmonary function returned to baseline levels 4 to 10 days sooner after LC. Pulmonary complications including atelectasis and hypoxia were less frequent after LC. An eight-fold decrease was noted in postoperative pain medication requirement in the LC group.

CONCLUSIONS

Compared to OC, laparoscopic cholecystectomy results in a significantly reduced compromise in pulmonary function and narcotic requirement leading to fewer postoperative pulmonary complications. Laparoscopic cholecystectomy should be considered the procedure of choice for elective cholecystectomy.

Selective sparing after lesions of visual cortex in newborn kittens

Previous findings are discordant regarding the effects of perinatal lesions of Cortical Areas 17 and 18 on visual discrimination learning in cats. Three potential determinants of such sparing were investigated: age at lesion (4 or 181 days), age at testing (3 or 9 months), and stimulus complexity. Age at testing was not significant, but performance varied with stimulus complexity and cortical damage, and there was an interaction between stimulus complexity and age at lesion. Both operated groups were transiently impaired in discriminating objects and subsequently learned to discriminate simple 2-dimensional patterns as well as done by controls, but the lesion groups were permanently impaired in discriminating similar patterns circumscribed by irrelevant lines. The age-at-lesion groups differed, however, in discriminating patterns masked by superimposed lines. The group lesioned at 181 days was severely impaired at both acquisition and subsequent intercurrent performance; the group lesioned at 4 days was impaired only at intercurrent performance. This study suggests that sparing after early postnatal damage of Areas 17 and 18 occurs only under limited circumstances.

Appetitive learning by old mice

Groups of C57BL/6J (B6) and DBA/2J (D2) mice, aged 100 to 700 days, were trained on 7 appetitive learning tasks in order to determine which tasks might be suitable for studies of learning by old mice. Old B6 and D2 mice were both deficient in learning a discrimination reversal and two complex maze tasks; age did not affect performance on a simple spatial discrimination by subjects from either strain. Three tasks yielded strain-specific results. Old B6, but not old D2, animals were impaired on a visual discrimination problem. On a test of latent learning, old B6 animals were superior to younger mice, but the reverse trend characterized the D2 mice. Older D2 mice were retarded on a food-seeking task; B6 mice of all ages failed this test. The deficits observed in learning by old mice are thus strain- as well as task-specific. However, the deprivation procedures of this experiment resulted in excessive mortality in the oldest groups of mice, indicating that appetitive learning is contraindicated as a method for investigating learning by old mice.

Effects of environmental enrichment on old mice

Fifteen male C57BL/6J mice, exposed to an enriched environment from age 600 to 750 days, were compared with 15 matched controls on 4 learning problems and an activity test. The enriched mice were significantly superior on an incidental learning and a food-seeking task, but did not differ significantly from controls on a brightness discrimination task, the Lashley III maze and an activity test. The relative abundance of high and low ribonucleic acid-containing cerebrocortical cells differed significantly between groups; the enriched mice had more cells with very high levels of RNA. The mammalian brain appears to remain responsive to environmental enrichment well into advanced age.