Early trauma and increased risk for physical aggression during adulthood: the moderating role of MAOA genotype

Previous research has reported that a functional polymorphism in the monoamine oxidase A (MAOA) gene promoter can moderate the association between early life adversity and increased risk for violence and antisocial behavior. In this study of a combined population of psychiatric outpatients and healthy volunteers (N = 235), we tested the hypothesis that MAOA genotype moderates the association between early traumatic life events (ETLE) experienced during the first 15 years of life and the display of physical aggression during adulthood, as assessed by the Aggression Questionnaire. An ANOVA model including gender, exposure to early trauma, and MAOA genotype as between-subjects factors showed significant MAOAxETLE (F(1,227) = 8.20, P = 0.005) and genderxMAOAxETLE (F(1,227) = 7.04, P = 0.009) interaction effects. Physical aggression scores were higher in men who had experienced early traumatic life events and who carried the low MAOA activity allele (MAOA-L). We repeated the analysis in the subgroup of healthy volunteers (N = 145) to exclude that the observed GxE interactions were due to the inclusion of psychiatric patients in our sample and were not generalizable to the population at large. The results for the subgroup of healthy volunteers were identical to those for the entire sample. The cumulative variance in the physical aggression score explained by the ANOVA effects involving the MAOA polymorphism was 6.6% in the entire sample and 12.1% in the sub-sample of healthy volunteers. Our results support the hypothesis that, when combined with exposure to early traumatic life events, low MAOA activity is a significant risk factor for aggressive behavior during adulthood and suggest that the use of dimensional measures focusing on behavioral aspects of aggression may increase the likelihood of detecting significant gene-by-environment interactions in studies of MAOA-related aggression.     

The great transformation: A long-run perspective on physical well-being in Canada

During the 19th century the physical stature of the Canadian-born stagnated or declined slightly in spite of a substantial increase in income. Stature varied regionally within Canada. The Quebec population was especially short; men in the Atlantic coastal region were taller than their low incomes would lead us to expect. Heights increased dramatically in the 20th Century. The pattern of long-run change is consistent with evidence of age-specific mortality and with the relationship between income and physical well-being envisaged by Preston [Preston, S., 1975. The changing relationship between mortality and the level of economic development. Popul. Stud. 29, 231-248]. The transition from stagnant or declining stature to secular increase points to a dramatic shift ca. 1900 in the evolution of the physical standard of living in Canada.     

Modulatory role of food, feeding regime and physical exercise on body weight and insulin resistance

Energy intake and expenditure is a highly conserved and well-controlled system with a bias toward energy intake. In times of abundant food supply, individuals tend to overeat and in consequence to increase body weight, sometimes to the point of clinical obesity. Obesity is a disease that is not only characterized by enormous body weight but also by rising morbidity for diabetes type II and cardiovascular complications. To better understand the critical factors contributing to obesity we performed the present study in which the effects of energy expenditure and energy intake were examined with respect to body weight, localization of fat and insulin resistance in normal Wistar rats. It was found that a diet rich in fat and carbohydrates similar to "fast food" (cafeteria diet) has pronounced implication in the development of obesity, leading to significant body weight gain, fat deposition and also insulin resistance. Furthermore, an irregularly presented cafeteria diet (yoyo diet) has similar effects on body weight and fat deposition. However, these rats were not resistant to insulin, but showed an increased insulin secretion in response to glucose. When rats were fed with a specified high fat/carbohydrate diet (10% fat, 56.7% carbohydrate) ad lib or at the beginning of their activity phase they were able to detect the energy content of the food and compensate this by a lower intake. They, however, failed to compensate when food was given in the resting phase and gained more body weight as controls. Exercise, even of short duration, was able to keep rats on lower body weight and reduced fat deposition. Thus, inappropriate food intake with different levels of energy content is able to induce obesity in normal rats with additional metabolic changes that can be also observed in humans.     

Oxidant,antioxidant and physical exercise

Generation of reactive oxygen species (ROS) is a normal process in the life of aerobic organisms. Under physiological conditions, these deleterious species are mostly removed by the cellular antioxidant systems, which include antioxidant vitamins, protein and non-protein thiols, and antioxidant enzymes. Since the antioxidant reserve capacity in most tissues is rather marginal, strenuous physical exercise characterized by a remarkable increase in oxygen consumption with concomitant production of ROS presents a challenge to the antioxidant systems.An acute bout of exercise at sufficient intensity has been shown to stimulate activities of antioxidant enzymes. This could be considered as a defensive mechanism of the cell under oxidative stress. However, prolonged heavy exercise may cause a transient reduction of tissue vitamin E content and a change of glutathione redox status in various body tissues. Deficiency of antioxidant nutrients appears to hamper antioxidant systems and augment exercise-induced oxidative stress and tissue damage. Chronic exercise training seems to induce activities of antioxidant enzymes and perhaps stimulate GSH levels in body fluids. Recent research suggest that supplementation of certain antioxidant nutrients are necessary for physically active individuals.     

Leukocyte kinetics in the human lung: role of exercise and catecholamines

In six normal supine subjects epinephrine infusion produced a greater leukocytosis with smaller changes in heart rate and blood pressure than did norepinephrine or isoproterenol. Upright exercise in those subjects produced a greater leukocytosis than supine exercise at the same work load. To determine the lung's participation in these events, indium-labeled neutrophils (PMN) were given to four of the subjects. We found that 20-25% were retained in the first pass through the lung when compared with technetium-labeled erythrocytes. The number of labeled PMN in the lung gradually decreased and the number in the spleen and the liver increased. Exercise and catecholamine infusion caused an acceleration in the release of labeled cells from the lung, an increase in both labeled and unlabeled cells in the peripheral blood, and an increase in the number of labeled cells in the liver and spleen. This suggests that increased perfusion of low-flow areas in the lung may contribute to the increased leukocytosis seen in association with both exercise and catecholamine infusion.     

Plasma protein carbonylation and physical exercise

Regular physical activity is associated with a reduced risk of coronary heart disease, as it probably modifies the balance between free-radical generation and antioxidant activity. On the other hand, however, acute physical activity increases oxygen uptake and leads to a temporary imbalance between the production of reactive oxygen and nitrogen species (RONS) and their disposal: this phenomenon is called oxidative stress. Proteins are one of the most important oxidation targets during physical exercise and carbonylation is one of the most common oxidative protein modifications. In cells there is a physiological level of oxidized proteins that doesn't interfere with cell function; however, an increase in oxidized protein levels may cause a series of cellular malfunctions that could lead to a disease state. For this reason the quantification of protein oxidation is important to distinguish a healthy state from a disease state. Several studies have demonstrated an increase of carbonylated plasma proteins in athletes after exercise, but none have identified targets of this oxidation. Recently a process of protein decarbonylation has been discovered, this may indicate that carbonylation could be involved in signal transduction. The aim of our research was to characterize plasma protein carbonylation in response to physical exercise in trained male endurance athletes. We analyzed by proteomic approach their plasma proteins at resting condition and after two different kinds of physical exercise (PE). We used 2D-GE followed by western blot with specific antibodies against carbonylated proteins. The 2D analysis identified Haptoglobin as potential protein target of carbonylation after PE. We also identified Serotransferrin and Fibrinogen whose carbonylation is reduced after exercise. These methods have allowed us to obtain an overview of plasma protein oxidation after physical exercise.     

Vascular tone and regular physical exercise

On the basis of the results of rheovasography of the thigh region, the vascular tone was assessed using pulse transit time in subjects regularly playing sports and nonathletes with initial stages of hypertension. An increased rigidity of the vascular wall was observed in subjects with an increased blood pressure. In our opinion, vascular endothelial dysfunction is the main cause of vascular rigidity, and regular dynamic training can improve the endothelium-dependent vascular relaxation.     

Comparative analysis of the effects of physical exercise

The purpose of this study was to assess anthropometrical, somatomotor, and cardio respiratory characteristics of athletes and non-athletes subjects to establish which effects of the organized physical training discriminate well between them. Subjects were 61 athlete and non-athlete medical students. Four groups were formed relying upon gender and physical activity. Body measures were computed. The motor abilities were tested by a set of static and dynamic motor tests, and cardio respiratory functions were recorded. No statistically significant differences were obtained from the comparisons of the body measures of basketball players and non-athlete medical students, except the body height. In contrast, significant differences were found both between the motor performances and between the cardio respiratory functions of the athlete and non-athlete groups. The body mass index (BMI) and the body fat (%) correlated negatively with static hanging, vertical jumping, and balance capability. On the contrary, BMI and body fat correlated positively with systolic blood pressure and vital capacity. The present results show that the effects of regular physical exercise on motor performances and cardio respiratory functions differentiate better between the athlete and non-athlete subjects than the changes in body measures.     

The relationship between chinook conditions and women's physical and mental well-being

The objective of this study was (1) to determine the relationship between chinook conditions and physical and psychological symptoms in women aged 20–49 years, and (2) to examine the possibility of subgroups of chinook-sensitive women. The evidence for this relationship is at present merely anecdotal. The study carried out in 1985–1986 in Calgary comprises the secondary analysis of a large survey of various health and health-related factors, including different symptoms, of urban women aged 20–49 years. The interview date was used to link these data to days on which pre-chinook, chinook, post-chinook and non-chinook conditions occurred. Between November 1, 1985 and February 28, 1986, 182 women were interviewed on pre-chinook days, 74 on chinook days, 229 on post-chinook days and 886 on non-chinook days. Autonomic reactions and skin disorders were found to be significantly related to chinook conditions. None of the psychological symptoms was related to chinook conditions. However, a significant relationship was found between symptoms and chinook conditions in women with a history of emotional disorders. This type of information is important to educate chinook-sensitive women and health professionals as well as for hospital emergency departments in order to be able to prepare for potential increases in workload.     

Human macrophage function and physical exercise: phagocytic and histochemical studies

Macrophages derived from human connective tissue were assayed for their enzyme content and phagocytic activity after physical exercise. A single exhaustive endurance-running test caused increased phagocytic and enzymatic activities of the macrophages. Thus, an exercise challenge activates the functional status of the cells. This effect of physical exercise on macrophages is inconsistent with the practical experience that high performance athletes suffer more frequently from harmless infectious diseases.     

Sudden death due to physical exercise in the elderly

Physical exercise has a beneficial effect to the humans. Sudden death in healthy persons engaged in physical exercise is extremely rare since healthy heart is protected from complications. The records of five elderly men who died during or immediately after exercise in the period between 1988-2001 in our region have been given, out of 23 men (and no one woman) aged 14-68 who died due to physical exercise in that time. They have been engaged in tennis, jogging and swimming recreatively. In all of them coronary heart disease has been found by the forensic autopsy. Only one has had arterial hypertension, symptoms of chest pain few years before accident and acute myocardial infarction has been found. The other four have been without symptoms. In three of them myocardial scars have been found of past myocardial infarctions. In all of them the thickness of the left ventricle wall was 15 mm or more (from 15 to 25 mm). It seems that the thickness of the wall of the left ventricle increases cardiovascular risk in persons without symptoms. In Croatia about 7% of the whole population are engaged in recreation. In this population 13% are elderly: 40,950. The reported five deaths due to recreational physical exercise in the elderly reached 1/114,660 persons every three years, or 1/573,300 persons during fourteen years.     

Thermoregulation in hyperhydrated men during physical exercise

The influence of hyperhydration on thermoregulatory function was tested in 8 male volunteers. The subjects performed cycle exercise in the upright position at 52% Vo2max for 45 min in a thermoneutral (Ta = 23 degrees C) environment. The day after the control exercise the subjects were hyperhydrated with tap water (35 ml X kg-1 of body weight) and then performed the same physical exercise as before. Total body weight loss was lower after hyperhydration (329 +/- 85 g) than during the control exercise (442 +/- 132 g), p less than 0.05. The decrease in weight loss after hyperhydration was probably due to a decrease in dripped sweat (58 +/- 64 and 157 +/- 101 g, p less than 0.05). With hyperhydration delay in onset of sweating was reduced from 5.8 +/- 3.2 to 3.7 +/- 2.0 min (p less than 0.05), and rectal temperature increased less (0.80 +/- 0.20 and 0.60 +/- 0.10 degrees C, p less than 0.01). The efficiency of sweating was higher in hyperhydrated (81.4%) than in euhydrated subjects (57.1%), p less than 0.01. It is concluded that hyperhydration influences thermoregulatory function in exercising men by shortening the delay in onset of sweating and by decreasing the quantity of dripped sweat. As a result, the increases in body temperature in hyperhydrated exercising men are lower than in normally hydrated individuals.     

Insect community organisation in estuaries: the role of the physical environment

Insects are reportedly uncommon in marine habitats and, from a spatial/temporal intercomparison perspective, estuaries are among the least studied. We examined the natural variability seen among insect community organisation in estuaries on both sides of the North Atlantic, and evaluated the role of their physical environments. Community composition was found to be strongly influenced by three physical factors: estuary size, the degree of inundation by incoming tides, and substrate size/stability. Insects formed a significant proportion (17–54%, by numbers) of the benthic community of coarse-grained-substratum estuaries, and species richness increased with estuary size. Nymphs/larvae of mayflies, stoneflies, caddisflies, elmid beetles and chironomids dominated channel sites inundated by up to 25% of all incoming tides, but a gradual loss in species richness occurred downstream. However, even the most seaward sites supported high insect densities (up to 25 016 and 5433 m⁻², supporting 26 and 4 species, at sites inundated by 75 and 100% of all incoming tides, respectively). Sites covered by tides for between 3 and 5 h twice daily were dominated by orthocladine chironomids, especially of the genus Orthocladius . Chironomid larvae contribute significantly to the diets of some coastal fish species, particularly juvenile flounder and sticklebacks. We present a schematic model summarising the relationships between estuary size, degree of inundation by salt water and insect community structure.     

The development of psychotic disorders in adolescence: A potential role for hormones

This article is part of a Special Issue “Puberty and Adolescence”.