Per Södersten

Treatment of childhood obesity by retraining eating behaviour: randomised controlled trial

Objective To determine whether modifying eating behaviour with use of a feedback device facilitates weight loss in obese adolescents. Design Randomised controlled trial with 12 month intervention. Setting Hospital based obesity clinic. Participants 106 newly referred obese young people aged 9-17. Interventions A computerised device, Mandometer, providing real time feedback to participants during meals to slow down speed of eating and reduce total intake; standard lifestyle modification therapy. Main outcome measures Change in body mass index (BMI) standard deviation score (SDS) over 12 months with assessment 18 months after the start of the intervention. Secondary outcomes were body fat SDS, metabolic status, quality of life evaluation, change in portion size, and eating speed. Results Using the last available data on all participants (n=106), those in the Mandometer group had significantly lower mean BMI SDS at 12 months compared with standard care (baseline adjusted mean difference 0.24, 95% confidence interval 0.11 to 0.36). Similar results were obtained when analyses included only the 91 who attended per protocol (baseline adjusted mean difference 0.27, 0.14 to 0.41; P<0.001), with the difference maintained at 18 months (0.27, 0.11 to 0.43; P=0.001) (n=87). The mean meal size in the Mandometer group fell by 45 g (7 to 84 g). Mean body fat SDS adjusted for baseline levels was significantly lower at 12 months (0.24, 0.10 to 0.39; P=0.001). Those in the Mandometer group also had greater improvement in concentration of high density lipoprotein cholesterol (P=0.043). Conclusions Retraining eating behaviour with a feedback device is a useful adjunct to standard lifestyle modification in treating obesity among adolescents. Trial registration ClinicalTrials.gov NCT00407420.

Increased cerebrospinal fluid concentration of nitrite in Parkinson's disease

The concentration of nitrite, a metabolite of nitric oxide (NO), was increased in the cerebrospinal fluid (CSF) of untreated patients with Parkinsons disease and in patients treated with L-DOPA in comparison with a group of patients without dopaminergic dysfunction. There was no difference in the concentration of L- arginine (ARG), a precursor of NO, between the groups. There was a highly significant, linear relationship between the concentration of nitrite and ARG in the CSF suggesting that the production of NO is dependent on the availability of ARG. The results support the possibility thatproduction of NO is increased in the brain in Parkinsons disease.

Randomized controlled trial of a treatment for anorexia and bulimia nervosa

Evidence for the effectiveness of existing treatments of patients with eating disorders is weak. Here we describe and evaluate a method of treatment in a randomized controlled trial. Sixteen patients, randomly selected out of a group composed of 19 patients with anorexia nervosa and 13 with bulimia nervosa, were trained to eat and recognize satiety by using computer support. They rested in a warm room after eating, and their physical activity was restricted. The patients in the control group (n = 16) received no treatment. Remission was defined by normal body weight (anorexia), cessation of binge eating and purging (bulimia), a normal psychiatric profile, normal laboratory test values, normal eating behavior, and resumption of social activities. Fourteen patients went into remission after a median of 14.4 months (range 4.9–26.5) of treatment, but only one patient went into remission while waiting for treatment (P = 0.0057). Relapse is considered a major problem in patients who have been treated to remission. We therefore report results on a total of 168 patients who have entered our treatment program. The estimated rate of remission was 75%, and estimated time to remission was 14.7 months (quartile range 9.6 ≥ 32). Six patients (7%) of 83 who were treated to remission relapsed, but the others (93%) have remained in remission for 12 months (quartile range 6–36). Because the risk of relapse is maximal in the first year after remission, we suggest that most patients treated with this method recover.

Sex differences in the brain: The relation between structure and function

In the fifty years since the organizational hypothesis was proposed, many sex differences have been found in behavior as well as structure of the brain that depend on the organizational effects of gonadal hormones early in development. Remarkably, in most cases we do not understand how the two are related. This paper makes the case that overstating the magnitude or constancy of sex differences in behavior and too narrowly interpreting the functional consequences of structural differences are significant roadblocks in resolving this issue.

Mating behavior in the male rat treated with p-chlorophenylalanine methyl ester alone and in combination with pargyline

The methyl-ester-hydrochloride of p-chlorophenylalanine alone (50 or 150 mg/kg i.p.) and in combination (4×100 mg/kg i.p.) with pargyline (100 mg/kg i.p.) caused a shortening of the ejaculation latencies in male rats and an increase in the number of intromissions per minute. No changes were observed in other components of the sexual behavior including intromission latency, post-ejaculatory interval and the number of mounts and intromissions preceding ejaculation.

Mating in male rats after section of the dorsal penile nerve

Abstract The dorsal penile nerve was sectioned in 12 male rats and their sexual behavior observed during a 2-month period. The males continued to show vigorous mounting behavior throughout the testing period but compared to intact animals the mating pattern was greatly impaired. All males displayed mounts and intromissions but only 4 animals ejaculated. The proportion of mounts without intromission was greatly increased. The animals which were able to ejaculate showed an increment in the number of mounts and intromissions preceding ejaculation and the ejaculatory latencies were accordingly prolonged. The impairment of sexual behavior was attributed to a reduced stimulatory effect of mounts and intromissions.

A daily rhythm in behavioral vasopressin sensitivity and brain vasopressin concentrations

The concentration of Arg-vasopressin (AVP) in the suprachiasmatic nuclei of the hypothalamus (SCN), the neural generator of circadian rhythms, showed a daily rhythm, which was inversely related to the rhythm in lordosis, an aspect of sexual behavior shown by ovariectomized estradiol-17 beta-treated female rats. A threshold dose of an AVP antagonist facilitated sexual behavior most effectively if injected intracerebroventricularly when the endogenous levels of AVP in the SCN were maximal and a threshold dose of AVP inhibited the behavior most effectively if injected when these levels were minimal. The results support the suggestion that AVP may be the neuropeptide whereby the SCN generate some behavioral rhythms.

Decelerated and linear eaters: effect of eating rate on food intake and satiety.

Women were divided into those eating at a decelerated or linear rate. Eating rate was then experimentally increased or decreased by asking the women to adapt their rate of eating to curves presented on a computer screen and the effect on food intake and satiety was studied. Decelerated eaters were unable to eat at an increased rate, but ate the same amount of food when eating at a decreased rate as during the control condition. Linear eaters ate more food when eating at an increased rate, but less food when eating at a decreased rate. Decelerated eaters estimated their level of satiety lower when eating at an increased rate but similar to the control condition when eating at a decreased rate. Linear eaters estimated their level of satiety similar to the control level despite eating more food at an increased rate and higher despite eating less food at a decreased rate. The cumulative satiety curve was fitted to a sigmoid curve both in decelerated and linear eater under all conditions. Linear eaters rated their desire to eat and estimated their prospective intake lower than decelerated eaters and scored higher on a scale for restrained eating. It is suggested that linear eaters have difficulty maintaining their intake when eating rate is dissociated from its baseline level and that this puts them at risk of developing disordered eating. It is also suggested that feedback on eating rate can be used as an intervention to treat eating disorders.

Mounting behavior in the female rat during the estrous cycle, after ovariectomy, and after estrogen or testosterone administration

Abstract Female rats displaying regular 4-day estrous cycles were tested for male sexual behavior with a receptive stimulus female during five consecutive estrous cycles, after ovariectomy, and after estrogen or testosterone treatment. Such behaviors as mounts (mount with pelvic thrusts), climbings (mount without pelvic thrusts), and sniffing at the genital area of the stimulus female varied systematically during the estrous cycle, being at minimal values when the rats were in heat. Intromission patterns (mount with pelvic thrusts accompanied by a final deep thrust and by genital grooming) were also displayed by most females but at relatively low rates. Ovariectomy decreased, but did not abolish masculine behavior. Estrogen in different doses (2, 10, and 50 μg/kg) stimulated the display of intromission patterns and mounts and depressed the frequency of climbings. The effects of various doses of testosterone (100, 500, and 2500 μg/kg) were similar to those of estrogen, i.e., testosterone stimulated the display of intromission patterns and mounts and depressed the frequency of climbings. No systematic dose-response relationships between amount of injected hormone and sniffing frequency or latencies to the first intromission pattern or mount could be detected. The results suggest that ovarian hormones may be involved in the regulation of male sexual behavior in the female rat.

Sexual behavior induces naloxone-reversible hypoalgesia in male rats

The sensitivity to painful and sexual stimuli in male rats was markedly suppressed immediately after ejaculation and enhanced after the postejaculatory refractory period. The suppression of pain sensitivity induced by sexual activity was reversed, but sexual behavior was only slightly affected by intraperitoneal (i.p.) injection of the opioid antagonist naloxone (5 mg). Plasma concentrations of beta-endorphin-like immunoreactivity were unaffected by sexual activity. Injection of beta-endorphin (10 micrograms s.c.) markedly raised plasma concentrations of beta-endorphin-like immunoreactivity within 1 min of injection but did not affect the sensitivity to painful stimulation or the display of sexual behavior. It is suggested that while ejaculation may activate opioid receptor mechanisms, which affect the sensitivity to painful, but not sexual, stimuli, elevation of beta-endorphin in the blood does not affect the sensitivity to either sexual or painful stimuli in male rats.