Epidemiological studies have shown that sleep debt increases the risk of obesity. Experimental total sleep deprivation (TSD) has been reported to activate the reward system in response to food ...stimuli, but food-related responses in everyday sleep habits, which could lead to obesity, have not been addressed. Here, we report that habitual sleep time at home among volunteers without any sleep concerns was shorter than their optimal sleep time estimated by the 9-day extended sleep intervention, which indicates that participants had already been in sleep debt in their usual sleep habits. The amygdala and anterior insula, which are responsible for both affective responses and reward prediction, were found to exhibit significantly lowered activity in the optimal sleep condition. Additionally, a subsequent one-night period of TSD reactivated the right anterior insula in response to food images; however, the activity level of amygdala remained lowered. These findings indicate that (1) our brain is at risk of hyperactivation to food triggers in everyday life, which could be a risk factor for obesity and lifestyle diseases, and (2) optimal sleep appears to reduce this hypersensitivity to food stimuli.
The thalamus, the region that forms the attentional network and transmits external sensory signals to the entire brain, is important for sleepiness. Herein, we examined the relationship between ...activity in the thalamus-seed brain network and subjective sleepiness.
Fifteen healthy male participants underwent an experiment comprising a baseline evaluation and two successive interventions, a 9-day sleep extension followed by 1-night total sleep deprivation. Pre- and post-intervention tests included the Karolinska sleepiness scale and neuroimaging for arterial spin labeling and functional connectivity. We examined the association between subjective sleepiness and the functional magnetic resonance imaging indices.
The functional connectivity between the left or right thalamus and various brain regions displayed a significant negative association with subjective sleepiness, and the functional connectivity between the left and right thalamus displayed a significant positive association with subjective sleepiness. The graph theory analysis indicated that the number of positive functional connectivity related to the thalamus showed a strong negative association with subjective sleepiness, and conversely, the number of negative functional connectivity showed a positive association with subjective sleepiness. Arterial spin labeling analysis indicated that the blood flow in both the left and right thalami was significantly negatively associated with subjective sleepiness. Functional connectivity between the anterior cingulate cortex and salience network areas of the left insular cortex, and that between the anterior and posterior cingulate cortices showed a strong positive and negative association with subjective sleepiness, respectively.
Subjective sleepiness and the thalamic-cortical network dynamics are strongly related, indicating the application of graph theory to study sleepiness and consciousness. These results also demonstrate that resting functional connectivity largely reflects the "state" of the subject, suggesting that the control of sleep and conscious states is essential when using functional magnetic resonance imaging indices as biomarkers.
The relationship between lipid or glucose metabolism and cancer has not yet been elucidated. We conducted 75-g oral glucose tolerance tests (75-g OGTTs) and lipid measurements between 1983 and 1985 ...in 516 Nagasaki atomic bomb survivors. Excluding those who already had cancer at the baseline examinations and those who developed cancers or died of any cause within 5 yr after the baseline examinations, we determined incident cancer cases until 2000 in the remaining 451 subjects (214 males and 237 females) and evaluated, by means of the Cox proportional hazard model, whether glucose or lipid metabolism predicts cancer development. The age- and sex-adjusted relative risk (RR) for incident cancer was 0.903 (95% confidence interval, CI = 0.842-0.968), 1.740 (95% CI = 1.238-2.446), 1.653 (95% CI = 0.922-2.965), and 1.024 (95% CI = 0.996-1.053) for total cholesterol (10 mg/dl), radiation dose (1 Sv), smoking, and 1-h blood glucose (1-h BG; 10 mg/dl) in 75-g OGTTs, respectively. Multiple regression analysis of age, sex, smoking, body mass index, 1-h BG, triglycerides, total cholesterol, high-density lipoprotein cholesterol, and radiation dose also showed that total cholesterol was negatively (RR = 0.872; 95% CI = 0.793-0.958) and radiation dose positively (RR = 1.809; 95% CI = 1.252-2.613) related to incident cancer. Cholesterol could be negatively and radiation dose positively associated with cancer development independently.
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DOBA, IJS, IZUM, KILJ, NUK, OILJ, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK, VSZLJ
A metabolic study was conducted to elucidate the effect of a diet enriched with various fatty acids in the form of triglycerides on serum lipids and lipoproteins in young women. The study was divided ...into two feeding periods of 5 days each, separated by a 7-day free diet period. Twelve healthy young women were divided into two groups, A (n=6) and B (n=6). The subjects in group A were fed a high-fat diet cooked with 60g/d triolein during the first period, and with 30 g/d tristearin during the second period. The subjects in group B were fed 60g/d trilinolein during the first period, and 30g/d tripalmitin during the second period. As well as the test fat, 10g/d beef tallow was added to the diet of both study groups during the second period to increase the test fatty acids and palatability of the test diet. The results obtained were as follows: 1) Significant decreases in mean serum total cholesterol, apo AI, AII and B, and LDL-cholesterol, -triglyceride and -phospholipids were observed after intake of the triolein or trilinolein diet. The serum HDL-cholesterol level was not affected by either diet. 2) The tristearin diet produced significant decreases in serum total cholesterol, LDL- and HDL-cholesterol, and apo AI and apo B. 3) The serum total and LDL-cholesterol levels were not affected by the tripalmitin diet, but the levels of HDL-cholesterol and apo AI were decreased significantly. The results of our short-term metabolic study suggest that the tested fatty acids do not increase the level of serum lipid when supplied in the form of triglyceride.
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