Physical activity and population health outcomes.
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Health Behavior↗
Biomedical subjects
S Trost
Publications and source records attributed to S Trost.
Couple dynamics of change-resistant smoking: toward a family consultation model.
Smoking is North America's leading cause of preventable morbidity and mortality. Although effective cessation treatments exist, their overall effect is modest, and they rarely reach the high-risk, health-compromised smokers who need them most. Surprisingly, despite evidence that marital relationship variables predict the success of cessation efforts, family systems ideas have had little impact on current intervention research. We review and critique the cessation literature from a systemic viewpoint, illustrate two couple-interaction patterns relevant to the maintenance of high-risk smoking, and outline a family-consultation (FAMCON) intervention for couples in which at least one partner continues to smoke despite having heart or lung disease. Taking into account ironic processes and symptom-system fit, FAMCON focuses on the immediate social context of smoking, aiming to interrupt well-intentioned "solutions" that ironically feed back to keep smoking going, and to help clients realign important relationships in ways not organized around tobacco usage. Currently in its pilot-testing phase, FAMCON is an adjunctive, complementary approach designed to include collaboration with primary-care physicians and to make smokers more amenable to other, evidence-based cessation strategies.
Couples Therapy↗
Cardiac ion channel expression and contractile function in mice with deletion of thyroid hormone receptor alpha or beta.
Cardiac myocytes express the two thyroid hormone receptors (T(3)Rs), T(3)Ralpha and T(3)Rbeta. However, which isoform contributes to specific, T(3)-induced alterations of cardiac function remains unclear. Here, we used individual T(3)R isoform knockout (KO) mice to study the effects of T(3)Ralpha and T(3)Rbeta in the heart. Our findings indicate that potassium channel genes that code for K(+) channels involved in action potential repolarization, like KV 4.2 and minK, are T(3)Ralpha targets. Both are markedly regulated by thyroid status. The recently identified cyclic nucleotide-gated channels, HCN2 and HCN4, are targets of T(3)Ralpha and are unchanged in a euthyroid T(3)Rbeta KO. However, these transcripts respond markedly to altered T(3) signaling concomitant with bradycardia in T(3)Ralpha KO and hypothyroid animals, as well as tachycardia in hyperthyroid T(3)Rss KO mice. SERCA2a and myosins are T(3) regulated and were also targets of T(3)Ralpha, and the papillary muscles of alphaKO animals showed a slowed rate of force development. Because of the absence of significant cardiac effects in euthyroid T(3)Rss KO mice, we determined messenger RNA levels for both T(3)Ralpha and T(3)Rss in the heart. We found that T(3)Rss is present at a 1:3 ratio to T(3)Ralpha1. We conclude that the cardiac phenotype regulated by T(3) is predominantly mediated by T(3)Ralpha and that the lack of T(3)Ralpha cannot be compensated by T(3)Rss in the heart.
Animals↗
Tracking of avoidance of alcohol use and smoking behavior in a fifth grade cohort over three years.
This study examined the maintenance of positive health behavior (avoidance of alcohol use and cigarette smoking) and factors associated with the maintenance of these behaviors from fifth through seventh grade by a cohort of rural students (N = 232). African American and White students showed similar patterns of high avoidance of alcohol until seventh grade. Although more girls avoided use than boys, avoidance decreased in both groups with progression in grade. Mothers', fathers', and best friends' drinking behaviors influenced avoidance behavior; drinking was less likely to occur among those whose parents and friends did not drink. Friends' drinking behavior influenced alcohol use as early as fifth grade. Smoking avoidance was maintained by 74% of the students over the 3 years. Although there were no racial differences in smoking, African Americans started smoking about 1 year earlier than Whites. During seventh grade, an increase in smoking occurred among boys and girls, but was particularly striking among girls. Avoidance of smoking was influenced by mothers' behavior but not fathers'. Best friends' smoking behavior exerted a major influence on avoidance between grades 6 and 7. In grades 5 and 6, those who avoided smoking were more physically active than smokers, but by seventh grade their physical activity declined to a similar level as smokers. Rural adolescent boys seemed to be at early risk for alcohol use and smoking, while rural girls delayed involvement by 1 to 2 years. Communities, schools, and families can help adolescents avoid alcohol use and smoking through early prevention efforts.
Black or African American↗
Health risk behaviors of rural sixth graders.
The purposes of this study were to examine the frequency and risk factors (correlates) of single and concurrent health risk behaviors (HRBs) including obesity, physical inactivity, smoking, and alcohol use in a sample of 352 rural, predominately African-American sixth graders. This study was guided by Jessor's (1992) adolescent risk behavior conceptual framework. Data were collected using physical measures and a self-report questionnaire. Thirty-two percent of the sample had no HRB, 44% had one HRB, and 24% had two or more HRBs. Obesity and physical inactivity were more prevalent in this sample than in the general population. Gender differences in risk factors were evident. Our findings suggest the testing of interventions that focus on the social needs of girls and that influence behavioral modeling for boys to reduce single and concurrent health risk behaviors.
Adolescent↗
Influence of forskolin on the force-frequency behavior in nonfailing and end-stage failing human myocardium.
UNLABELLED: End-stage failing human myocardium is characterized by a negative force-frequency relationship (FFR), possibly as a result of reduced SR Ca2+ uptake capacity. We investigated the effects of the direct adenylate cyclase stimulator, forskolin, on force of contraction and FFR in isolated human myocardium from 7 nonfailing hearts (NF) and end-stage failing hearts (NYHA IV) due to either ischemic (ICM; n = 13) or dilated cardiomyopathy (DCM; n = 16). METHODS: Isolated left ventricular muscle strips, isometric contraction, electrical stimulation at a basal stimulation rate of 1 Hz (37 degrees C). Inotropic responses: Cumulative concentration-response curves for forskolin (0.01-10 microM) and for Ca2+ (2.5-15 mM). Force-frequency experiments: stepwise increase in stimulation rate from 0.5 to 3.0 Hz without and in the presence of 0.3, 1.0 or 3.0 microM forskolin. RESULTS: Forskolin concentration-dependently increased force of contraction to 386 +/- 28% (n = 5) in NF, to 256 +/- 48% (n = 7) in ICM, and to 212 +/- 13% (n = 14) in DCM. The effectiveness of forskolin was significantly reduced in failing myocardium. Ca2+ increased force of contraction to maximally 438 +/- 108% in NF, to 267 +/- 15% in ICM, and to 292 +/- 20% in DCM. Again, the effectiveness of Ca2+ was significantly reduced in failing myocardium. Forskolin activated contractile reserve to similar extents in all types of myocardium (90%, 95%, and 82%, respectively). Force of contraction continuously increased with increasing stimulation rates in nonfailing myocardium (positive FFR), but was blunted or inversed in ICM and DCM. Prestimulation with forskolin (0.3 microM) further enhanced frequency-potentiation in nonfailing, and normalized the slope and optimum stimulation frequency in ICM and DCM. However, at higher concentrations of forskolin, FFR was blunted or inversed in non-failing myocardium, and further impaired in failing myocardium. CONCLUSION: Low concentrations of forskolin with only marginal inotropic effects may partially normalize the inverse force-frequency relation in end-stage failing human myocardium. Reduced cAMP levels in conjunction with reduced expression of SR Ca2+ ATPase may be the underlying cause for altered excitation-contraction coupling in diseased human hearts.
Biomechanical Phenomena↗
The effect of substrate utilization, manipulated by nicotinic acid, on excess postexercise oxygen consumption.
Increased fat oxidation during the recovery period from exercise is thought to be a contributing factor for excess postexercise oxygen consumption (EPOC). In an attempt to study the effect of serum free fatty acid (FFA) availability during exercise and recovery on the EPOC, nicotinic acid, a potent inhibitor of FFA mobilization from adipose tissue, was administered to five trained male cyclists prior to, during, and after a bout of cycling at 65% VO2max. In the nicotinic acid trial, a 500 mg dose of nicotinic acid was ingested prior to exercise, and 100 mg doses were ingested at 15, 30, and 45 min exercise, and 30 min recovery. The cyclists also completed a trial under control conditions. Serum FFA, serum glycerol, RER and VO2 were monitored during rest, exercise, and recovery, each of which was 1-h in duration. Nicotinic acid ingestion prevented the increase in serum FFA that occurred during exercise in the control trial. FFA levels during the nicotinic acid trial were significantly lower than control values during both exercise and recovery. Serum glycerol levels were also significantly lower during exercise in the nicotinic acid trial, indicative of a reduction in lipolysis. RER was not significantly different at rest or during exercise; however, RER values were significantly lower during recovery in the control trial, indicative of greater fat oxidation. For both treatments, postexercise VO2 remained elevated above resting levels at the completion of the 1-h recovery period. However, the magnitude of EPOC was significantly reduced after FFA blockade with nicotinic acid (3.4 +/- 0.61 vs 5.5 +/- 0.71). These results support the hypothesis that increased FFA metabolism during exercise and recovery is an important contributing factor to the magnitude of EPOC.
Adipose Tissue↗
Predictors of alcohol use among rural adolescents.
There is increasing evidence that alcohol use is becoming more common during childhood and early adolescence. However, little is known about alcohol use among rural youths. This article reports a study of alcohol use among 367 fifth-grade students in two rural South Carolina school districts. More than one third (n = 131) of the fifth graders reported having used alcohol. Of these, 34 percent (n = 44) reported drinking during the previous month; 8 percent had been intoxicated during the previous two months; and 54 percent reported drinking in the home with or without parental approval. Logistic regression analysis was used to determine the predictors of alcohol use by fifth graders. The results indicated that gender (OR = 2.82), mother's alcohol use (OR = 1.86), father's alcohol use (OR = 2.13), and smoking (OR = 8.30) were significantly associated with alcohol use. The findings suggest that prevention programs address cigarette smoking and drinking behaviors of parents to reduce alcohol use and the acquisition of other health compromising behavior by youths. Early intervention approaches must go beyond the schools and target families as well as community populations.
Adolescent↗
Murine monoclonal antibodies to the myelin-associated glycoprotein react with large granular lymphocytes of human blood.
Monoclonal antibodies prepared to human myelin-associated glycoprotein were shown to react with a population of human peripheral blood mononuclear cells. The population is similar to the large granular lymphocytes or natural killer cells defined by antibody Leu 7 (also called HNK-1). The population also includes cells exhibiting the Leu 2 marker for suppressor/cytotoxic T cells. The results indicate a shared antigenicity between the nervous system and the immune system and may be relevant to the pathogenesis of demyelinating diseases.
Animals↗
Phorbol ester-induced changes in human leukemic pre-B lines.
The genomic analysis of four non-T-leukemic lines NALM-1, KM-3, NALL-1, and NALM-16 shows a rearranged configuration of the immunoglobulin mu chain genes, indicating that they represent early B stages of differentiation. The differentiative potential of these pre-B cell lines was tested using the phorbol ester tumor promoter 12-O-tetradecanoyl phorbol-13-acetate (TPA). Phenotypic changes in the immunological marker profile (induction of BA-1 and BA-2 antigens) are observed, presumably reflecting events occurring in precursor B cells. However, no maturation to immunoglobulin mu chain production could be obtained. The limited maturation can be explained on the basis of possible aberrant mu chain gene rearrangements, or other mechanisms of a regulatory nature, preventing the transcription and/or the translation of rearranged mu chain genes.
Antigens, Neoplasm↗
Idiopathic unilateral hydronephrosis in a cat.
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Animals↗