Publications

Cohen, B. I.; Sallis, J. F. FACSM; Long, B. J.; Calfas, K. J.; Wooten, W. J.; Patrick, K.; Hovell, M. F. Author Information

Most research on relapse from exercise has investigated one relapse episode following a structured program. The present study examined the patterns and determinants of the lifetime history of relapse from exercise in a community population. Subjects were 1,811 randomly selected residents of San Diego, California who completed an extensive mailed survey. Subjects reported the number of times over their lifetime that they had exercised vigorously for at least six months and then stopped exercising for at least three months. Approximately 60% of subjects reported zero relapses, 20% reported one or two relapses, and 20% reported three or more relapses. Relapse histories of current exercisers and current nonexercisers were virtually identical. The most commonly reported reason for the last relapse was injuries for both nonexercisers and exercisers. Multiple regression analyses were used to identify correlates of exercise relapse history. These data indicate that cross-sectional surveys of exercise behavior are inadequate to characterize exercise behavior in a population, and injuries are probably a major cause of relapse.

In this study DNA-binding and gene transfer experiments were performed to examine a potential glucocorticoid regulatory element (GRE) in the human growth hormone gene. As assayed by nitrocellulose filter binding, only two regions of the human growth hormone gene, the 5'-flanking sequences and a fragment containing part of the first intron, were retained preferentially by purified glucocorticoid-receptor complexes. The relative binding by the transcribed sequences was three times greater than the relative binding by the 5'-flanking sequences, but less than the relative binding by a fragment containing the human metallothionein-IIA gene GRE. The intron, but not the 5'-flanking sequences, generated a "footprint" when the receptor complex was used to protect the segments against exonuclease III digestion; the protected sequence spanned nucleotides +86 to +115 in the first intron and contained a structure homologous in 14 of 16 nucleotides to a 16-nucleotide consensus GRE. The hexanucleotide 5'-TGTCCT-3', thought to be important for GRE activity, not only was found in this sequence and in the 5'-flanking region, but also was present twice in the 3' end of the gene that did not show specific receptor binding. The latter results suggest that the hexanucleotide alone is not sufficient to generate specific receptor binding tight enough to be assayed in this way. To test the biological activity of the intron binding site, a fragment containing these sequences was fused 5' to the human metallothionein-IIA gene promoter depleted of its GRE and linked to the structural sequences of the herpes simplex virus thymidine kinase (TK) gene. When this hybrid gene was transfected into Rat 2 TK- cells, its expression was induced threefold by the glucocorticoid dexamethasone, as assessed by transfection efficiency and RNA blotting analyses. Expression of the same gene without the human growth hormone gene segment was not affected by the steroid, whereas the wild-type human metallothionein-IIA gene promoter containing its GRE responded to the hormone by a sixfold increase in thymidine kinase mRNA. These results indicate that the human growth hormone gene contains a structure within its first intron that can function as a GRE.

This study assessed the comparability and reliability of paper-based and computer-based administration of psychosocial construct measures related to adolescents engaging in physical activity and sedentary behaviors. Adolescents (n = 76; 55% girls, 49% Hispanic, 18% non-Hispanic-white; M age = 13 years) completed measures of behavior change strategies, selfefficacy, decisional balance, family and peer influences, enjoyment, activity choices, and environmental influences. Overall, the adolescents provided equivalent responses on paper and computer formats. Reliability estimates were generally good for the multiple-item constructs, but single-item measures tended to demonstrate low reliability. Average scale internal consistency was significantly higher for measures administered with the computer format compared to the paper format, but test-rest reliability estimates were not significantly different between formats. Key words: exercisehealth surveysInternetreproducibility of results Additional informationNotes on contributorsGregory J. Norman This work was partially supported by grants CA81495 and CA85873 from the National Cancer Institute. Portions of this paper were presented at the Society of Behavioral Medicine's 24th Annual Sessions, Salt Lake City, UT, March 2003. We would like to acknowledge the assistance of Peter Ryan for computer programming and Lindsay Radick for data collection. Please address all correspondence concerning this article to Gregory J. Norman, Department of Family and Preventive Medicine, University of California, San Diego, 9500 Gilman Drive, Dept. 0811, La Jolla, CA 92093.

Abstract NF-κB, a key activator of inflammation primes the NLRP3-inflammasome for activation by inducing pro-IL-1β and NLRP3 expression. NF-κB, however, also prevents excessive inflammation and restrains NLRP3-inflammasome activation through a poorly defined mechanism. We now show that NF-κB exerts its anti-inflammatory activity by inducing delayed accumulation of the autophagy receptor p62/SQSTM1. External NLRP3-activating stimuli trigger a form of mitochondrial (mt) damage that is caspase-1- and NLRP3-independent and causes release of direct NLRP3-inflammasome activators, including mtDNA and mtROS. Damaged mitochondria undergo Parkin-dependent ubiquitin conjugation and are specifically recognized by p62, which induces their mitophagic clearance. Macrophage-specific p62 ablation causes pronounced accumulation of damaged mitochondria and excessive IL-1β-dependent inflammation and enhances macrophage death. Therefore, the “NF-κB-p62-mitophagy” pathway is a macrophage-intrinsic regulatory loop through which NF-κB restrains its own inflammation-promoting activity and orchestrates a self-limiting host response that maintains homeostasis and favors tissue repair. Citation Format: Zhenyu Zhong, Michael Karin. NF-kB restricts inflammasome activation via elimination of damaged mitochondria [abstract]. In: Proceedings of the Second CRI-CIMT-EATI-AACR International Cancer Immunotherapy Conference: Translating Science into Survival; 2016 Sept 25-28; New York, NY. Philadelphia (PA): AACR; Cancer Immunol Res 2016;4(11 Suppl):Abstract nr A066.

To investigate the construct, concurrent and predictive validity of stage of change measures for physical activity (PA), and intakes of fruit and vegetables (FVs), dietary fiber (FB) and dietary fat (DF) among a sample of overweight women. Subjects were 401 women (mean age=41, s.d.=8.7 years; mean body mass index=32.35, s.d.=4.6) recruited to participate in a 12-month weight loss intervention trial. Concurrent validity tests included (1) self-report of current behavior, (2) decisional balance (for example, pros and cons of behavior change), (3) self-efficacy, (4) the MTI Actigraph accelerometer (for the PA staging measure), and (5) a food-frequency questionnaire (for all dietary staging measures). Predictive validity was assessed through tests of the relationship between the baseline stage of change measures and their corresponding behavior 1-year later. Coefficient α-tests of internal consistency exceeded 0.70 on the majority of scales. Concurrent validity tests indicated strong validity evidence for three staging measures and little validity for the DF staging measure (η2 range, 0.02–0.18). All staging algorithms demonstrated predictive validity (η2 range, 0.04–0.126). Staging measures can determine motivational readiness for overweight women, contribute to the standardization of stage of change assessment and facilitate cross-study comparisons.

Tracking and explaining physical activity in young adults was investigated in a 7-year longitudinal design. From a representative sample of 980 respondents at baseline (M age = 21 years), 172 respondents, comprising 18% of the original sample, completed psychosocial questionnaires and were interviewed at home to assess their level of physical activity at follow-up. Psychosocial variables were grouped into four groups: social variables, self-efficacy, perceived benefits, and perceived barriers. Drop-out analyses showed no major differences between the baseline and follow-up samples. The aims of the present study were: (a) to investigate tracking in physical activity and psychosocial determinants over a 7-year period, and (b) to examine baseline determinants and change in determinants in predicting physical activity change in men and women. No significant tracking of physical activity level was found for men. For women, moderate tracking scores were found for total energy expenditure and moderate-intensity energy expenditure (r = .34 and .41, respectively). There was higher tracking in psychosocial determinants than in physical activity. Relatively high tracking scores for perceived benefits and barriers suggest that cognitions related to physical activity are more stable than the behavior itself. Although baseline psychosocial variables were poor predictors of physical activity change, determinants'change scores accounted for 16-19% of the variance in physical activity in men and 7-24% in women. Significant predictors were different for men and women. Present results can inform the design of physical activity interventions for these populations.