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Biomedical subjects

L H Epstein

Publications and source records attributed to L H Epstein.

At least 73 records · Page 4Linked to original sources
PubMed1994

Child and parent factors that influence psychological problems in obese children.

This study assessed the influence of child and parental obesity and parental psychiatric symptoms on psychological problems in obese 8-11-year-old children. Child psychological problems were measured using the Child Behavior Checklist/4-18, whereas adult psychiatric symptoms were measured using the Cornell Medical Index. Multiple linear regression analyses showed parental psychiatric symptoms were related to child psychological problems for six of eight problem behavior scales. Child obesity made no independent contribution to child psychological problems, and parental obesity was related to child problems on only one scale. The most prevalent problems were Anxiety/Depression for 15% of the boys and Social Problems for 20% of the boys and 12.8% of the girls. These results suggest a broader conceptualization of factors that influence behavior problems of obese children than their degree of obesity.

Adult↗
PubMed1994

Child and parent psychological problems influence child weight control.

This study used path analytic methods to assess the influence of child psychopathology measured using the Child Behavior Checklist and parent psychiatric symptoms measured using the Cornell Medical Index on changes in child percent overweight in obese 8- to 11-year-old children over 2 years (6 months of treatment, 18 months of follow-up) provided family-based behavioral intervention. Path analysis for the 0-6 month change showed the influence of mother and father psychiatric symptoms and child age on child anxiety/depression scores that in turn influenced child percent overweight change during treatment, accounting for 41% of the shared variance. The path analysis for follow-up change showed mother and father psychiatric symptoms influenced child social problems at the first stage, and child social problems influenced child percent overweight change, accounting for 68.5% of the shared variance. These results provide the first demonstration that both parent and child problems may influence the short- and long-term success of obese children who participate in family-based behavioral treatment programs.

Adult↗
PubMed1994

Year-long weight loss treatment for obese patients with type II diabetes: does including an intermittent very-low-calorie diet improve outcome?

PURPOSE: To evaluate a year-long behavioral weight control program, used with and without an intermittent very-low-calorie diet (VLCD) in the treatment of type II diabetes mellitus. PATIENTS AND METHODS: Subjects (n = 93) were randomly assigned to 50-week treatment programs that used either a balanced low-calorie diet (LCD) of 1,000 to 1,000 kilocalories (kcal) per day throughout or included 2 12-week periods of a VLCD of 400 to 500 kcal per day alternating with the balanced LCD. Weight, glycemic control, blood pressure, and lipids were assessed at baseline, at the end of the year-long treatment, and at 2-year follow-up. RESULTS: Subjects in the VLCD program lost significantly more weight than did LCD subjects at the end of the 50-week program (14.2 kg versus 10.5 kg; P = 0.057) and remained off diabetes medication longer (P < 0.05). These benefits of the VLCD were due primarily to the first 12 weeks of the diet; the second diet maintained, but did not increase, these effects. Subjects in both groups experienced marked improvements in glycemic control and cardiovascular risk factors over the year-long program, but attendance declined in the latter weeks of treatment and weight was regained. There was also marked recidivism in both groups in the year following treatment. CONCLUSIONS: The intermittent VLCD improved weight loss and glycemic control, but these effects were quite modest and do not appear to justify the clinical use of an intermittent VLCD. Moreover, lengthening treatment to a full year did not prevent relapse. Thus, further research is needed to develop a successful approach to long-term weight control.

Adult↗
PubMed1994

Tobacco abstinence, smoking cues, and the reinforcing value of smoking.

One definition of the reinforcing value of a drug is the degree to which an organism will work to obtain it. Male and female smokers (n = 8 each) engaged in a task involving concurrent schedules of reinforcement for responding to receive cigarette puffs versus money on four occasions, following overnight abstinence versus no abstinence and in the presence of a lit cigarette (smoking "cue") or with no cigarette (2 x 2 design). Reinforcement schedule for puffs ranged from variable ratio 4 (VR4) to VR32, with schedule order during the first five trials (VR4 first, VR32 first) counterbalanced and repeated in reverse sequence during the second five trials. Schedule for money remained at VR4 during all trials. Results indicated significantly greater responding for puffs after overnight abstinence and in the presence of the smoking cue, although effect of the cue was specific to the "leaner" VR schedules (VR16, VR32). Unexpectedly, not only was reinforcement schedule for puffs a significant determinant of responding, but the order of these schedules (i.e., VR4 first vs. VR32 first) produced a significant overall difference in responding for puffs, especially in the presence of the cue. There was no difference in responding between males and females. These findings indicate that the reinforcing value of smoking is increased by overnight abstinence, the presence of a lit cigarette under lean reinforcement conditions, and the order in which reinforcement schedules are presented.

Adult↗
PubMed1994

Immunological effects of acute and chronic nicotine administration in rats.

We previously demonstrated that acute nicotine administration decreased the response of rat blood leukocytes (PBL) to concanavalin A (ConA). We now extend those findings to a comparison between the effects of acute and prolonged nicotine exposure (ten daily injections), on PBL and splenocytes (SL). A single injection suppressed the PBL response to ConA and phytohemagglutinin (PHA); tolerance developed by ten injections. In contrast, acute nicotine did not affect SL response to ConA and reduced the PHA response only at the highest concentration. Ten nicotine injections enhanced SL responsiveness to PHA. The only change in PBL subsets was an increase in CD8+ cells following ten injections.

Animals↗
PubMed1994

Ten-year outcomes of behavioral family-based treatment for childhood obesity.

We report 10-year treatment outcomes for obese children in 4 randomized treatment studies. At 10 years, 34% decreased percentage overweight by 20% or more, and 30% were not obese. Significant effects were observed when parents and children were targeted and reinforced for weight loss in comparison with nontargeted controls and for children given lifestyle or aerobic exercise in comparison with a calisthenics control. Thirty-four percent of the variance in change in percentage overweight was predicted from sex, baseline percentage overweight, self-monitoring weight, meals eaten at home, and family and friends' support for eating and exercise. Results show long-term changes in children depend on the treatment, and evidence converges on the importance of the family and other sources of support for eating and activity change.

Adolescent↗
PubMed1994

Acute thermogenic effects of nicotine combined with caffeine during light physical activity in male and female smokers.

The thermogenic effects of nicotine and caffeine during physical activity compared with rest were examined in male and female smokers (n = 10 each). During eight sessions, nicotine (15 micrograms/kg) or placebo was given via measured-dose nasal spray intermittently after consumption of decaffeinated coffee with or without added caffeine (5 mg/kg), followed by assessment of energy expenditure by indirect calorimetry while subjects engaged in standardized, low-intensity cycle ergometer riding (activity) or remained at quiet rest. Results indicated significant thermogenic effects of nicotine and caffeine individually, with the combination of nicotine and caffeine producing additive effects. Expenditure attributable to nicotine, caffeine, or their combination was significantly enhanced during activity compared with rest, but only for males and not females. Plasma nicotine concentrations were influenced by activity and caffeine, but these pharmacokinetic changes did not appear to explain the differences in expenditure. These findings suggest a sex difference in thermogenic effects of nicotine and caffeine during casual physical activity and potentially explain some of the apparent individual variability in expenditure due to tobacco smoking.

Administration, Intranasal↗
PubMed1994

Nonhomologous recombination in human cells.

Nonhomologous recombination (NHR) is a major pathway for the repair of chromosomal double-strand breaks in the DNA of somatic cells. In this study, a comparison was made between the nonhomologous end joining of transfected adenovirus DNA fragments in vivo and the ability of purified human proteins to catalyze nonhomologous end joining in vitro. Adenovirus DNA fragments were shown to be efficiently joined in human cells regardless of the structure of the ends. Sequence analysis of these junctions revealed that the two participating ends frequently lost nucleotides from the 3' strands at the site of the joint. To examine the biochemical basis of the end joining, nuclear extracts were prepared from a wide variety of mammalian cell lines and tested for their ability to join test plasmid substrates. Efficient ligation of the linear substrate DNA was observed, the in vitro products being similar to the in vivo products with respect to the loss of 3' nucleotides at the junction. Substantial purification of the end-joining activity was carried out with the human immature T-cell-line HPB-ALL. The protein preparation was found to join all types of linear DNA substrates containing heterologous ends with closely equivalent efficiencies. The in vitro system for end joining does not appear to contain any of the three known DNA ligases, on the basis of a number of criteria, and has been termed the NHR ligase. The enriched activity resides in a high-molecular-weight recombination complex that appears to include and require the human homologous pairing protein HPP-1 as well as the NHR ligase. Characterization of the product molecules of the NHR ligase reaction suggests that they are linear oligomers of the monomer substrate joined nonrandomly head-to-head and/or tail-to-tail. The joined ends of the products were found to be modified by a 3' exonuclease prior to ligation, and no circular DNA molecules were detected. These types of products are similar to those required for the breakage-fusion-bridge cycle, a major NHR pathway for chromosome double-strand break repair.

Adenoviridae↗
PubMed1993

Methodological issues and ten-year outcomes for obese children.

In our research we have shown that obese children can lose weight and maintain this change in body composition over extended periods throughout development. Treatment variables that are important include having the parents as active participants in the treatment of their children and including exercise programs along with diet. The motivational structures within the family that support or discourage behavior change, however, may be as important as the specific behaviors that we attempt to modify. For example, we have observed successful long-term outcome in families in which we have used conjoint or reciprocal contracts, but not in families in which the child alone was targeted for behavior change. The specific methodology for including parents and children in treatment may be important, or it may just be important for both parents and children to be targeted for change and family members taught to support the behavior change of the other family members. Future research with children should pay attention to methods that mobilize family support for behavior change in multiple family members and strive for methods that will modify the sources of support for the targeted child, which will generalize to other family members.

Body Height↗
PubMed1993

Effect of weight loss by obese children on long-term growth.

OBJECTIVE: To assess height growth over 10 years in children treated for obesity. DESIGN: Longitudinal, prospective follow-up of a series of randomized, controlled weight control trials. SETTING: Specialized pediatric weight control clinic. PARTICIPANTS: One hundred fifty-eight 6- to 12-year-old obese children who were followed up for 10 years after treatment. INTERVENTIONS: Family-based behavioral weight control. MEASUREMENTS/MAIN RESULTS: At entry the height percentiles of the obese children were significantly higher (71.6 percentile) than same-sex parent (52.0 percentile) or midparent (51.5 percentile) height (an estimate of parental contribution to height). After an average growth of 22.7 cm, children were 2.2 cm taller than their same-sex parent and decreased to an average height percentile of 57.8. Multiple regression analysis showed that child sex, age, baseline height and percent overweight, midparent height, and height change of the child from baseline to 5 years accounted for 94% of the variance in growth. Child percent overweight change made no contribution to predicting height change. Comparison between children obese and nonobese at 10 years showed no differences in growth. CONCLUSIONS: Moderate energy restriction with dietary guidance by overweight children did not negatively influence long-term growth.

Body Height↗
PubMed1993

Acute stress or corticosterone administration reduces responsiveness to nicotine: implications for a mechanism of conditioned tolerance.

We have shown that conditioned tolerance develops to some of the behavioral and endocrine effects of nicotine in rats. Other investigators have suggested that tolerance to multiple nicotine injections in mice may be due, in part, to elevated plasma corticosterone (CORT) levels, since repeated nicotine injections are associated with elevated CORT, chronically elevated CORT reduces nicotine responsiveness and adrenalectomy disrupts nicotine tolerance. Three experiments tested the feasibility of this hypothesis, as a mechanism for conditioned nicotine tolerance in rats, by determining whether acute administration of CORT or manipulations that increase adrenocortical activity reduce nicotine responsiveness. In experiment 1, male rats were injected IP with CORT (1 mg/kg), vehicle (ETOH + distilled water) or no injection 10 min before nicotine (0.75 mg/kg, SC) and tested for nicotine-induced analgesia every other day for 10 days. A significant reduction in withdrawal latencies was obtained for CORT pretreated rats compared to animals given only nicotine. A similar reduction was produced by the vehicle pretreatment, which itself induced an elevation of endogenous CORT. Experiments 2 and 3 established that similar effects could be produced by doses of CORT as low as 0.125 mg/kg or by exposure to a novel environment which also elevated CORT levels. Results also suggest that a conditioned release of endogenous CORT was triggered by stimuli associated with nicotine delivery. These data are consistent with the hypothesis that a conditioned release of CORT could contribute to the development of tolerance to some of nicotine's effects.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

The effect of subjective and physiological arousal on dishabituation of salivation.

We have previously shown that salivation to the same food habituates, and recovers after presenting novel nontaste stimuli. This study assessed the effects of environmental stimuli that differentially influence subjective and autonomic arousal on dishabituation of salivation. Thirty female subjects were preloaded on a lemon yogurt milkshake and habituated to seven presentations of lemon juice. Prior to the eighth presentation of juice, subjects were presented an engaging video game designed to produce subjective but no autonomic arousal (LO), a video game plus mental arithmetic stressor, designed to produce both subjective and physiological arousal (HI), or a no stimuli (REST) control. Significant dishabituating effects of HI versus REST were shown for salivation. Heart rate was significantly higher during the dishabituator for HI than LO or REST conditions, which were equal. Finally, significant differences in arousal were shown between each of the three conditions. These results show salivation can be differentially dishabituated by nonfood stimuli, and these stimuli influence salivation without influencing subjective hunger or hedonics.

Adolescent↗
PubMed1993

Chronic and acute tolerance to subjective effects of nicotine.

Tolerance to subjective effects of nicotine may induce novice smokers to increase the magnitude and frequency of their nicotine self-dosing. In this study, smokers (n = 8) and nonsmokers (n = 7) participated in three sessions involving presentation of 0, 7.5, or 15 micrograms/kg nicotine 30 min for 2 h via measured-dose nasal spray, with different doses presented on separate days. Subjective responses were assessed using visual analog scales (VASs) of jittery, light-headed, relaxed, dizzy, and head rush, and the Profile of Mood States (POMS) scales of vigor, confusion, fatigue, tension, and the composite scale of arousal. Smaller responses in smokers vs. nonsmokers were viewed as evidence for chronic tolerance. In addition, on each day subjects received a fifth, challenge dose of 30 micrograms/kg 30 min after the previous dosing. Smaller responses to the challenge dose as a function of increasing prior nicotine dosing during Trials 1-4 were viewed as evidence for acute tolerance. Results showed significant changes in most measures as a function of nicotine dose, and the dose-response curves for most VAS and POMS scales tended to be shifted to the right, or dampened, in smokers relative to nonsmokers, consistent with chronic tolerance. However, smokers and nonsmokers tended to respond to nicotine in opposite directions for POMS scales of vigor and arousal, perhaps reflecting withdrawal relief in smokers. Acute tolerance on a few selected VAS and POMS scales was apparent for both smokers and nonsmokers.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

Effects of nicotine on hunger and eating in male and female smokers.

We tested whether the inverse relationship between smoking and body weight may be due in part to nicotine's acute effects on reducing hunger and eating. On four mornings, male and female smokers (n = 10 each), abstinent overnight from smoking and food, received one of three nicotine doses (7.5, 15, and 30 micrograms/kg) or placebo (0) via nasal spray every 30 min for 2 h. Self-reported hunger and satiety ("fullness") and craving for cigarettes were obtained after each dose presentation. Subjects subsequently ate ad lib from a large array of food items varying in sweet taste and fat content. For both males and females, nicotine had no effect on self-reported hunger, but cigarette craving was decreased. Rather than being decreased, caloric intake during the meal was unexpectedly increased following nicotine compared with placebo. Cigarette craving increased after the meal, and this increase was unaffected by nicotine dose. There were virtually no differences between males and females in any effects of nicotine. These results indicate that nicotine may not acutely suppress appetite in fasting smokers and suggest that other actions of nicotine or smoking may account for the lower body weights of smokers.

Adolescent↗
PubMed1992

Habituation and dishabituation of human salivary response.

Habituation may be relevant for understanding how sensory stimuli influence factors related to ingestive behavior. In the first of three experiments in humans we showed that salivation and hedonic ratings to lemon or lime juice habituated within 10 presentations, and dishabituation of the salivation and hedonic ratings to the original juice were observed after a new juice was presented. Experiment 2 replicated the habituation and decrease in hedonics to lemon juice, and showed both dishabituation and a relative increase in hedonics when chocolate taste, rather than another juice, served as the dishabituating stimulus. In a third experiment we showed a video game, a nontaste stimulus, could serve as a distractor to prevent the development of habituation, as well as a dishabituator after habituation had occurred.

Adolescent↗
PubMed1992

Abstinence from smoking decreases habituation to food cues.

Smokers typically gain weight after cessation due, in part, to increased caloric intake. This increase may be due to enhanced responding to sensory characteristics of foods resulting from a failure to habituate to food cues. To test this possibility, salivation to eight presentations of strawberry yogurt was assessed in male smokers and nonsmokers in two sessions. To test stimulus specificity, on the ninth trial, subjects were presented either more strawberry yogurt or lemon yogurt. Smokers were studied under nonabstinent or abstinent conditions. Salivation for nonabstinent smokers and nonsmokers decreased over presentations, while abstinent smokers showed little change. Nonabstinent smokers and nonsmokers recovered salivation when the new flavor yogurt was presented, and showed greater consumption on the final trial for the different versus same flavor yogurt. Nonabstinent smokers participated in additional within-session smoking sessions to control for withdrawal. Nonabstinent subjects were not different across smoking or not smoking sessions, suggesting the effects are not due to the acute effects of withdrawal.

Adolescent↗