Publications

Short-term sleep curtailment associated with activation of the stress system in healthy, young adults has been shown to be associated with decreased leptin levels, impaired insulin sensitivity, and increased hunger and appetite. To assess the effects of one night of sleep loss in a less stressful environment on hunger, leptin, adiponectin, cortisol and blood pressure/heart rate, and whether a 2-h mid-afternoon nap reverses the changes associated with sleep loss, 21 young healthy individuals (10 men, 11 women) participated in a 7-day sleep deprivation experiment (four consecutive nights followed by one night of sleep loss and two recovery nights). Half of the subjects were randomly assigned to take a mid-afternoon nap (14:00-16:00 hours) the day following the night of total sleep loss. Serial 24-h blood sampling and hunger scales were completed on the fourth (predeprivation) and sixth day (postdeprivation). Leptin levels were significantly increased after one night of total sleep loss, whereas adiponectin, cortisol levels, blood pressure/heart rate, and hunger were not affected. Daytime napping did not influence the effects of sleep loss on leptin, adiponectin, or hunger. Acute sleep loss, in a less stressful environment, influences leptin levels in an opposite manner from that of short-term sleep curtailment associated with activation of the stress system. It appears that sleep loss associated with activation of the stress system but not sleep loss per se may lead to increased hunger and appetite and hormonal changes, which ultimately may lead to increased consumption of 'comfort' food and obesity.

To compare the incidence of hypovitaminosis D in subjects, with and without type 2 diabetes mellitus (T2DM), and determine its association to various risk factors.Three hundred and forty-one (177 non-diabetic, and 164 T2DM) Saudi adults were included in this cross-sectional study conducted at the Biomarkers Research Program (BRP) of King Saud University, Riyadh, Kingdom of Saudi Arabia from March to August 2009. Anthropometrics and fasting blood samples were obtained. Fasting glucose (FG) and lipid profiles were determined. Serum 25-hydroxy vitamin D (25[OH]D) and parathyroid hormone (PTH) were quantified using enzyme-linked immunosorbent assay. Severe hypovitaminosis D was defined as serum 25(OH)D with levels <12.5 nmol/l.Age was the most significant predictor of 25(OH)D in both groups, explaining 25% (p=0.0005) and 16% of variances (p=0.0005). Waist-hip ratio, systolic blood pressure and body mass index were significant predictors of 25(OH)D among non-diabetics after age adjustment, explaining 21% of variance perceived (p=0.039). Serum PTH levels were higher in non-diabetic men and women.Severe hypovitaminosis D is prevalent in both non-diabetic and diabetic Saudis, but was more common in the young and middle-aged non-diabetics. The study further underscores the need for vitamin D fortification of the Saudi diet, and the promotion of vitamin D supplementation in both groups.

Saline lavage of the major bronchial segments was performed in five patients immediately preceding lobectomy to remove an ACTH-producing bronchial carcinoid. Lavage fluid from each bronchus was concentrated, and ACTH determinations were performed. Elevated concentrations of ACTH were not demonstrated in the aspirate from the bronchus containing the known tumor. Two additional patients with ectopic ACTH syndrome from an unknown primary source also underwent selective segmental bronchial lavage for ACTH determination. Neither patient demonstrated ACTH gradients in the lavage specimens. One was found to have an ACTH-producing bronchial carcinoid 18 months after negative lavage. Selective segmental bronchoscopic lavage with measurement of ACTH levels on the aspirate is not an effective technique for detecting ACTH-producing bronchial carcinoid tumor.

Petrides, John S., Philip W. Gold, Gregory P. Mueller, Anita Singh, Costas Stratakis, George P. Chrousos, and Patricia A. Deuster.Marked differences in functioning of the hypothalamic-pituitary-adrenal axis between groups of men. J. Appl. Physiol. 82(6): 1979–1988, 1997.—To compare profiles of hypothalamic-pituitary-adrenal (HPA) responsiveness, healthy, moderately trained men ( n = 15) were classified as high ( n = 7) or low responders ( n = 8) on the basis of plasma adrenocorticotropic hormone (ACTH) responses to strenuous treadmill exercise 4 h after 4 mg of dexamethasone (Dex). These groups were then evaluated to compare 1) HPA and growth hormone responses to exercise at 90% maximal oxygen uptake 4 h after placebo, Dex (4 mg), and hydrocortisone (100 mg); 2) pituitary-adrenal responses to infusion of arginine vasopressin (AVP); 3) plasma cortisol after a Dex suppression test (1 mg); and 4) behavioral characteristics. In comparison to low responders, high responders exhibited significantly 1) higher plasma ACTH responses to exercise after placebo and Dex; 2) higher plasma AVP secretion with exercise after placebo and marked Dex- and hydrocortisone-induced enhancement of exercise-induced AVP secretion; 3) lower Dex-induced increases in basal and stimulated growth hormone secretion; 4) higher plasma ACTH responses to infusion of AVP; and 5) a trend ( P = 0.09) for higher trait anxiety ratings. Similar suppression of plasma cortisol was noted after 1 mg Dex. We conclude that subgroups of healthy male volunteers exhibit unique profiles of HPA responsiveness. We also believe that glucocorticoid pretreatment combined with strenuous exercise allows functional HPA responsiveness to be distinguished between subgroups of healthy controls and may be useful in the determination of susceptibility to disorders characterized by hyper- and hypo-HPA activation.

In experimental animals, stress and catecholamines stimulate endogenous interleukin-6 (IL-6) secretion, whereas glucocorticoids inhibit it. To examine whether physical stress alters the secretion of IL-6 in humans, and to what extent this is correlated with catecholamines and modified by glucocorticoids, we performed high-intensity treadmill exercise test runs on 15 male volunteers, in a double-blind crossover design, after pretreatment with placebo, hydrocortisone, or dexamethasone. Plasma epinephrine and norepinephrine concentrations peaked 15 min after the start of exercise, whereas plasma IL-6 concentrations peaked twice, 15 min and 45 min after the onset of the test run. There was no difference in either the epinephrine or norepinephrine peaks among the three treatments, but the net area under the curve for IL-6 was smaller after hydrocortisone or dexamethasone than after placebo and smaller after dexamethasone than after hydrocortisone. A positive correlation was observed between peak plasma epinephrine or norepinephrine and IL-6 levels at 15 min. These findings suggest that IL-6 secretion is stimulated during exercise, possibly by catecholamines, whereas exogenous glucocorticoids attenuate this effect without affecting the catecholamine levels.

Exposure to anthropogenic electromagnetic fields (EMFs), especially those of wireless communications (WC) has increased tremendously. This is an unprecedented phenomenon throughout biological evolution because, all anthropogenic EMFs, being fully polarized, coherent, and, especially WC EMFs, highly variable, differ substantially from the natural EMFs. WC EMFs consist of Microwave (MW) carrier waves, modulated, by Extremely Low Frequency (ELF) signals, and included in on/off pulses repeated at various ELF rates. Moreover, they exhibit intense random variability, mainly in the Ultra Low Frequency (ULF) band. Thus, WC EMFs are a combination of MW and ELF/ULF EMFs. The combination of polarization/coherence and intense low-frequency (ELF/ULF) variability seems to be the key to EMF-bioactivity. Epidemiological and laboratory studies highlight a connection between ELF or WC EMF exposure and cancer, infertility, electro-hypersensitivity, and various other pathologies. Studies also find DNA damage and Oxidative Stress (OS) which explain these pathologies. While man-made EMFs cannot directly ionize molecules, they are capable of doing this indirectly in biological tissue, by triggering the biosynthesis of Reactive Oxygen Species (ROS) which can damage biomolecules, including DNA. The (over)production of ROS and the consequent OS are triggered by irregular gating of Voltage-Gated Ion Channels (VGICs) in the cell membranes as described by the Ion Forced Oscillation (IFO)-VGIC mechanism: Mobile ions within VGICs forced to oscillate by the applied ELF/ULF EMFs exert forces on the voltage sensors of the VGICs, similar to or greater than the forces that physiologically gate those channels, resulting in their irregular gating (dysfunction). Dysfunction of ion channels disrupts intracellular ionic concentrations. This triggers ROS overproduction and OS by the ROS-generating systems/enzymes in the cells, such as the electron transport chain (ETC) in the mitochondria, or the NADPH/NADH oxidases (NOXs), the Nitric Oxide synthases (NOS), etc. The IFO-VGIC mechanism and the consequent OS constitute a comprehensive mechanism that explains all known adverse biological and health effects reported to be induced by anthropogenic EMFs.

This study evaluated the short-term responses of physiological and psychological indices and examined the human senses that are mostly engaged during a green space and urban exposure in residents of Athens, Greece. The forest had beneficial effects for human physiology, anxiety and mood states and was also associated with all five senses and positive reactions, while the opposite was observed in the urban center. The difference of pre- and post-green space exposure salivary cortisol was correlated with the participants’ environmental profile and body mass index. Green spaces can alleviate stress and improve overall mood, while helping individuals experience their surroundings with all five senses.