Evening preference correlates with regional brain volumes in the anterior occipital lobe

Chronotype or diurnal preference is a questionnaire-based measure influenced both by circadian period and by the sleep homeostat. In order to further characterize the biological determinants of these measures, we used a hypothesis-free approach to investigate the association between the score of the morningness-eveningness questionnaire (MEQ) and the Munich chronotype questionnaire (MCTQ), as continuous variables, and volumetric measures of brain regions acquired by magnetic resonance imaging (MRI). Data were collected from the Baependi Heart Study cohort, based in a rural town in South-Eastern Brazil. MEQ and anatomical 1.5-T MRI scan data were available from 410 individuals, and MCTQ scores were available from a subset of 198 of them. The average MEQ (62.2 ± 10.6) and MCTQ (average MSFsc 201 ± 85 min) scores were suggestive of a previously reported strong general tendency toward morningness in this community. Setting the significance threshold at P > .002 to account for multiple comparisons, we observed a significant association between lower MEQ score (eveningness) and greater volume of the left anterior occipital sulcus (β = -0.163, p = .001) of the occipital lobe. No significant associations were observed for MCTQ. This may reflect the smaller dataset for MCTQ, and/or the fact that MEQ, which asks questions about preferred timings, is more trait-like than the MCTQ, which asks questions about actual timings. The association between MEQ and a brain region dedicated to visual information processing is suggestive of the increasingly recognized fluidity in the interaction between visual and nonvisual photoreception and the circadian system, and the possibility that chronotype includes an element of masking.

Heritability of semantic verbal fluency task using time-interval analysis

Individual variability in word generation is a product of genetic and environmental influences. The genetic effects on semantic verbal fluency were estimated in 1,735 participants from the Brazilian Baependi Heart Study. The numbers of exemplars produced in 60 s were broken down into time quartiles because of the involvement of different cognitive processes—predominantly automatic at the beginning, controlled/executive at the end. Heritability in the unadjusted model for the 60-s measure was 0.32. The best-fit model contained age, sex, years of schooling, and time of day as covariates, giving a heritability of 0.21. Schooling had the highest moderating effect. The highest heritability (0.17) was observed in the first quartile, decreasing to 0.09, 0.12, and 0.0003 in the following ones. Heritability for average production starting point (intercept) was 0.18, indicating genetic influences for automatic cognitive processes. Production decay (slope), indicative of controlled processes, was not significant. The genetic influence on different quartiles of the semantic verbal fluency test could potentially be exploited in clinical practice and genome-wide association studies.

Nutritional aspects of eating episodes followed by vomiting in Brazilian patients with bulimia nervosa

BACKGROUND

The clinical aspects of bulimia nervosa (BN) are similar in countries with different sociocultural backgrounds, but less is known about dietary composition in patients from developing countries. Little is also known about the role that nutritional aspects may play in behaviours aimed at counteracting the effects of binge eating.

OBJECTIVES

To describe the daily energy intake and eating behaviour of BN patients in Brazil and compare the dietary patterns of the patients who terminated eating episodes by vomiting and those patients who did not.

METHODS

Thirty patients from an eating disorders programme in a university-affiliated hospital completed a 14-day dietetic diary; the data were analysed using nutritional software.

RESULTS

Mean age and BMI of the patients were respectively 27.2 +/- 9.6 years and 25.5 +/- 6.7 Kg/m2. The patients in the vomiting subgroup ate more irregularly and consumed a more variable number of meals per day than those in the non-vomiting subgroup. The daily energy intake of the patients as a whole was 2,202 kcal, with a macronutrient composition of 53% carbohydrates, 31% fats and 17% proteins. The mean energy intake of the eating episodes followed by vomiting was 1,331 kcal with a macronutrient profile of 51% carbohydrates, 36% fat and 14% protein. Intake and eating patterns were characterised by between- and within- individual variability, and so no significant differences were found in the subgroup comparisons. Foods with a high energy density were preferred during the eating episodes followed by vomiting.

CONCLUSIONS

The results indicate that patients who vomit have a more irregular and variable eating pattern than those who do not vomit, but their daily nutrient content is comparable.

Individual reactivity and physiology of the stress response

The biological response to stress involves the activation of two main neuroendocrine components, the hypothalamic-pituitary-adrenal axis and the sympathoadrenal medullary systems. Looking at the responses to stressors in a laboratory setting, e.g., cortisol production after exercising on a treadmill, is a valid and controlled way to study how people react to psychological and physical stressors. A common finding in such studies is that individuals respond bimodally to stress. More recently, researchers have been interested in the possible reasons why healthy individuals exhibit differential reactivity to stressors. The literature on the neuroendocrine responses to stress, with a particular focus on investigations of individual reactivity to psychological and physical stressors, is reviewed.

Case series: increased vulnerability to obsessive-compulsive symptoms with repeated episodes of Sydenham chorea

The association between obsessive-compulsive symptoms (OCS) and Sydenham chorea (SC) supports the hypothesis of a common neuroimmunological dysfunction in basal ganglia associated with group A beta-hemolytic streptococcal infection underlying both conditions. Four children with 2 distinct SC episodes were evaluated to assess the course of OCS. All patients developed OCS during their second episodes (3 met criteria for obsessive-compulsive disorder [OCD]), but not in their first episodes (2 developed OCS and met criteria for OCD). These data suggest that the recurrence of SC episodes may result in a cumulative effect, thus increasing the risk of appearance and intensification of OCS.

Sex differences in circulating human leptin pulse amplitude: clinical implications

Leptin, a product of fat cells, provides a signal of nutritional status to the central nervous system. Leptin concentrations have ultradian and diurnal fluctuations. We conducted this study to assess sex differences in the levels of organization of frequently sampled leptin concentrations in healthy, normal weight women and men. Leptin levels were sampled every 7 min for 24 h in 14 healthy, normal weight individuals (6 women and 8 men). The 14 leptin time series containing a total of 2898 leptin measurements were assessed by 1) algorithms that characterize statistically significant pulsatility, 2) Spectral (Fourier) analysis, 3) analysis of time intervals and variability, and 4) approximate entropy. We found that frequently sampled plasma leptin concentrations have a 24-h profile that is numerically more than twice as high in women as in men, and leptin pulse amplitude is likewise more than twice as high in women. However, healthy men and women have nearly identical concentration-independent and frequency-related 24-h and ultradian patterns. Leptin concentrations have nonrandom fluctuations over 24 h, independent of their absolute value and underlying 24-h periodicity, that are similar in men and women. Ultradian periodicities detected by Fourier time series have similar values in men and women. The strongest distinction between the sexes in the level of organization of leptin concentration is not at the level of pulse organization or oscillation frequency, but, rather, in the mass or amount of leptin released (or removed) per unit time, indicating that women might be more resistant to the effects of leptin than men. Because leptin is clinically relevant to the regulation of body weight, future studies should examine whether the relative leptin resistance exhibited by women might contribute to their increased susceptibility to disorders whose pathophysiology involves dysregulation of food intake and body weight.

Obsessive-compulsive and related symptoms in children and adolescents with rheumatic fever with and without chorea: a prospective 6-month study

OBJECTIVE

The incidence and course of neuropsychiatric symptoms were determined in pediatric patients with rheumatic fever.

METHOD

The Leyton Obsessional Inventory and National Institute of Mental Health Global Obsessive-Compulsive Scale were used to evaluate children and adolescents who had rheumatic fever with Sydenham's chorea (N=30) or without chorea (N=20). They were assessed three times over 6 months from the onset of rheumatic fever. Psychiatric diagnoses were also determined.

RESULTS

Obsessive-compulsive symptoms abruptly appeared and peaked during the 2 months after the onset of rheumatic fever in 21 patients with chorea (70.0%) and were absent in all patients without chorea. Obsessive-compulsive disorder (OCD) was diagnosed in five patients with chorea (16.7%).

CONCLUSIONS

The association between Sydenham's chorea and OCD supports suggestions that similar mechanisms involving the basal ganglia underlie both disorders. Obsessive-compulsive symptoms occurred at the beginning of rheumatic fever, so early psychopathological assessments are essential.

Synchronicity of frequently sampled, 24-h concentrations of circulating leptin, luteinizing hormone, and estradiol in healthy women

Leptin, an adipocyte hormone, is a trophic factor for the reproductive system; however, it is still unknown whether there is a dynamic relation between fluctuations in circulating leptin and hypothalamic-pituitary-ovarian (HPO) axis hormones. To test the hypothesis that fluctuations in plasma leptin concentrations are related to the levels of luteinizing hormone (LH) and estradiol, we sampled plasma from six healthy women every 7 min for 24 h during days 8-11 of the menstrual cycle. Cross-correlation analysis throughout the 24-h cycle revealed a relation between release patterns of leptin and LH, with a lag of 42-84 min but no significant cross-correlation between LH and estradiol. The ultradian fluctuations in leptin levels showed pattern synchrony with those of both LH and estradiol as determined by cross-approximate entropy (cross-ApEn). At night, as leptin levels rose to their peak, the pulsatility profiles of LH changed significantly and became synchronous with those of leptin. LH pulses were fewer, of longer duration, higher amplitude, and larger area than during the day. Moreover, the synchronicity of LH and leptin occurred late at night, at which time estradiol and leptin also exhibited significantly stronger pattern coupling than during the day. We propose that leptin may regulate the minute-to-minute oscillations in the levels of LH and estradiol, and that the nocturnal rise in leptin may determine the change in nocturnal LH profile in the mid-to-late follicular phase that precedes ovulation. This may explain the disruption of hypothalamic-pituitary-ovarian function that is characteristic of states of low leptin release, such as anorexia nervosa and cachexia.

Plasma leptin levels are increased in survivors of acute sepsis: associated loss of diurnal rhythm, in cortisol and leptin secretion

Recent animal and human studies have suggested that leptin secretion is closely linked to the functions of the hypothalamic-pituitary-adrenal (HPA) axis and the immune system, both of which are crucial in influencing the course and outcome of critical illness. Therefore, we measured basal plasma leptin levels and examined the circadian secretion of leptin, in parallel with the hormones of the HPA axis and a key cytokine, interleukin-6, in critically ill patients with acute sepsis. Sixteen critically ill patients from the University of Leipzig Intensive Care Unit were recruited for this study. All of these patients fulfilled the standard diagnostic criteria for sepsis. Plasma leptin levels were measured in all patients and controls at 09:00. In addition, in a subgroup of eight critically ill patients and all of the nine controls plasma leptin, cortisol, ACTH and interleukin-6 concentrations were measured every 4 hours for 24 hours. Mean plasma leptin levels were three-fold higher (18.9 +/- 4.5 ng/ml) in critically ill patients than controls (3.8 +/- 1.0 ng/ml, p < 0.05). Similarly, ACTH levels were lower (7.8 +/- 3.4 pmol/l) in patients than in controls (17.1 +/- 1.5 pmol/l, p < .001), while plasma cortisol levels were increased (947.6 +/- 144 nmol/l) in patients compared to controls (361.1 +/- 29, p < 0.001). Morning plasma interleukin-6 levels were markedly elevated in all patients with sepsis (1238.0 +/- 543.1 pg/ml) versus controls (6.4 +/- 1.7, p < 0.001). The controls exhibited a nyctohemeral fluctuation in plasma leptin levels with peak levels at 23:00; in contrast, septic patients, had no nocturnal rise of leptin. In healthy controls, plasma leptin and cortisol had reciprocal circadian rhythms with high nocturnal leptin levels and low nocturnal cortisol concentrations; in critically ill patients, this relation was abolished. Mean leptin levels were three-fold higher in patients who survived the septic episode (25.5 +/- 6.2, n = 10) than in non-survivors (8.0 +/- 3.7, n = 6, p < 0.01). We conclude that in addition to its function as an anti-obesity factor, leptin may play a role in a severe stress state such as acute sepsis.

Human leptin levels are pulsatile and inversely related to pituitary-adrenal function

Leptin communicates nutritional status to regulatory centers in the brain. Because peripheral leptin influences the activity of the highly pulsatile adrenal and gonadal axes, we sought to determine whether leptin levels in the blood are pulsatile. We measured circulating leptin levels every 7 minutes for 24 hours, in six healthy men, and found that total circulating leptin levels exhibited a pattern indicative of pulsatile release, with 32.0 +/- 1.5 pulses every 24 hours and a pulse duration of 32.8 +/- 1.6 minutes. We also show an inverse relation between rapid fluctuations in plasma levels of leptin and those of adrenocorticotropic hormone (ACTH) and cortisol that could not be accounted for on the basis of glucocorticoid suppression of leptin. As leptin levels are pulsatile, we propose that a key function of the CNS is regulated by a peripheral pulsatile signal. In a separate pilot study we compared leptin pulsatility in 414 plasma samples collected every 7 minutes for 24 hours from one obese woman and one normal-weight woman. We found that high leptin levels in the obese subject were due solely to increased leptin pulse height; all concentration-independent pulsatility parameters were almost identical in the two women. Leptin pulsatility therefore can be preserved in the obese.

Clinical characteristics and course of anorexia nervosa in Latin America, a Brazilian sample

The authors present the clinical description of a sample of anorexic patients from an eating disorder program from a non-English developing country. The patients were diagnosed according to DSM-III-R criteria and treated with a multidisciplinary approach. Similarities to and differences from other Western patient studies are discussed.

Childhood sexual abuse and bulimia nervosa: a comparison of American, Austrian, and Brazilian women

OBJECTIVE

This study was designed to assess the prevalence of childhood sexual abuse among women with bulimia nervosa in three countries: the United States, Austria, and Brazil. In addition, it assessed whether bulimic subjects might have experienced more severe sexual abuse than women in the general population and whether bulimic subjects who report abuse might display greater psychopathology than those who do not report abuse.

METHOD

Thirty-three university students in Innsbruck, Austria, 33 university students in Boston, and 25 women in São Paulo, Brazil, all meeting DSM-III-R criteria for bulimia nervosa, were recruited by advertisement. Detailed histories of sexual abuse, obtained at the conclusion of a comprehensive evaluation interview, were prepared, translated into English, and rated by an investigator who was blind to the nationality of the subject. Subjects were compared on frequency of eating binges, history of major depression, body mass index, and satisfaction with body image.

RESULTS

Narrowly defined childhood sexual abuse was reported by 24%-36% of women in the three countries, although only 15%-32% of women reported abuse before the onset of bulimia nervosa. There were no significant differences between countries in rates of abuse. Overall, these rates appear no greater than those reported in comparable studies of women in the general population. The data also did not support the hypothesis that bulimic subjects had endured more severe sexual abuse than other women, nor was there a significant association between history of childhood sexual abuse and severity of bulimic symptoms.

CONCLUSIONS

These findings add to the weight of evidence suggesting that childhood sexual abuse is not a risk factor for bulimia nervosa.