Physiological and behavioral rhythms are governed by an endogenous circadian clock. In this paper are reported the studies on soldier's circadian of melatonin concentrations by means of electricity and light pulses presented to the popliteal region (behind the knee). The results showed that the phase of melatonin concentrations can be regulated by both the electricity pulses and the light pulses. A systematic relation was found between the timing of the electro-stimulating and the magnitude and direction of phase shifts, resulting in the generation of a phase response curve. The phase response curve displayed photic model. These findings have implications for the development of more effective treatments for sleep and circadian rhythm disorders.
Adolescent ; Adult ; Chronobiology Disorders ; prevention & control ; Circadian Rhythm ; physiology ; radiation effects ; Electric Stimulation ; Humans ; Male ; Melatonin ; blood ; physiology ; Military Personnel ; Photic Stimulation ; Sleep Disorders, Circadian Rhythm ; prevention & control

OBJECTIVETo investigate the effects of extremely low frequency magnetic and electric fields (ELFEMFs) emitted from 380 kV transmission lines on some leukocyte differentiation antigens in dairy cows.

METHODSThe study was carried out in 5 cows exposed to 1.98-3.28 microT of ELFEMFs and in 5 control cows exposed to 0.2-0.7 microT of ELFEMFs. Following haematological and immunologic parameters were measured in both groups: WBC, CD45R, CD6, CD4, CD8, CD21, and CD11B leukocyte antigen expression.

RESULTSSome of the haematological and immunologic parameters under investigation were similar in both groups. However, CD8 (T lymphocyte surface antigen) was higher in the exposed group (1.35 +/- 0.120 vs. 0.50 +/- 0.14 x 10(3)/mL). Furthermore, the CD4/CD8 ratio (0.84 +/- 0.05 and 2.19 +/- 0.16 for exposed and not exposed cows respectively) and circadian rhythm were different between the two groups.

CONCLUSIONExposure to ELFEMFs is responsible of the abnormal temporal variations and distribution of some haematological and immunological parameters in dairy cows.

Animals ; Antigens, CD ; blood ; Cattle ; Circadian Rhythm ; radiation effects ; Electromagnetic Fields ; Environmental Exposure ; analysis ; Female ; Leukocytes ; immunology

BACKGROUNDThe exaggerated surge in morning blood pressure (BP) that many patients experience upon awakening may be closely related to target organ damage and may be a predictor of cardiovascular complications. However, no previous studies have evaluated the rate of this surge independently of the evening period. It remains unclear whether the rate of increase experienced during the surge is a significant or independent determinant of cardiovascular events.

METHODSWe randomly selected 340 ambulatory BP monitoring (ABPM) patients. All subjects without type 2 diabetes mellitus were divided into two groups: hypertensive group (n = 170) and normotensive group (n = 170). We analyzed ambulatory blood pressure recordings using a double logistic curve-fitting procedure to determine whether the magnitude of the surge in BP and heart rate (HR) in the morning is related to the level of BP in hypertensive individuals. We evaluated the association between the rate of the morning surge in systolic BP (SBP) and the incidence of myocardial infarction and stroke in normotensive and hypertensive subjects.

RESULTSComparisons between hypertensive and normotensive subjects showed that the rates of the morning surges in SBP, mean BP (MBP), and diastolic BP (DBP) were greater in the hypertensive group (P < 0.05) than in the normotensive group. The rate of morning surge in BP was found to be correlated with the daytime SBP (r = 0.236, P < 0.01), the difference between the day and night plateau (r = 0.249, P < 0.01), and the night SBP (r = -0.160, P < 0.05), respectively. After controlling for age, sex, and mean systolic pressure within 24 hours (24 h SBP), the rate of morning surge in SBP was closely correlated with daytime SBP (r = 0.463, P < 0.001), night SBP (r = -0.173, P < 0.05), and the difference between the day and night plateau (r = 0.267, P < 0.001). Logistic regression analysis revealed that the rate of morning surge in SBP was an independent determinant of myocardial infarction (OR = 1.266, 95% CI = 1.153 - 1.389, P < 0.001) and stroke (OR = 1.367, 95% CI = 1.174 - 1.591, P < 0.001).

CONCLUSIONSThe rate of the morning surge in BP is greater in hypertensive subjects than in normotensive subjects. Daytime SBP may be the best predictor of the rate of morning surge in SBP. The rate of the morning surge in BP is associated with cardiovascular and stroke events.

Adult ; Aged ; Blood Pressure ; physiology ; Blood Pressure Monitoring, Ambulatory ; Circadian Rhythm ; physiology ; Female ; Heart Rate ; radiation effects ; Humans ; Hypertension ; physiopathology ; Male ; Middle Aged ; Stroke ; physiopathology

BACKGROUND: Exposure to the ionizing radiation (IR) encountered outside the magnetic field of the Earth poses a persistent threat to the reproductive functions of astronauts. The potential effects of space IR on the circadian rhythms of male reproductive functions have not been well characterized so far. METHODS: Here, we investigated the circadian effects of IR exposure (3 Gy X-rays) on reproductive functional markers in mouse testicular tissue and epididymis at regular intervals over a 24-h day. For each animal, epididymis was tested for sperm motility, and the testis tissue was used for daily sperm production (DSP), testosterone levels, and activities of testicular enzymes (glucose-6-phosphate dehydrogenase (G6PDH), sorbitol dehydrogenase (SDH), lactic dehydrogenase (LDH), and acid phosphatase (ACP)), and the clock genes mRNA expression such as Clock, Bmal1, Ror-α, Ror-β, or Ror-γ. RESULTS: Mice exposed to IR exhibited a disruption in circadian rhythms of reproductive markers, as indicated by decreased sperm motility, increased daily sperm production (DSP), and reduced activities of testis enzymes such as G6PDH, SDH, LDH, and ACP. Moreover, IR exposure also decreased mRNA expression of five clock genes (Clock, Bmal1, Ror-α, Ror-β, or Ror-γ) in testis, with alteration in the rhythm parameters. CONCLUSION These findings suggested potential health effects of IR exposure on reproductive functions of male astronauts, in terms of both the daily overall level as well as the circadian rhythmicity.
ARNTL Transcription Factors/genetics* ; Acid Phosphatase ; Animals ; CLOCK Proteins/genetics* ; Circadian Rhythm/radiation effects* ; Epididymis/radiation effects* ; Gene Expression/radiation effects* ; Genitalia, Male/radiation effects* ; Glucosephosphate Dehydrogenase ; L-Iditol 2-Dehydrogenase ; L-Lactate Dehydrogenase ; Male ; Mice ; Mice, Inbred C57BL ; Models, Animal ; Nuclear Receptor Subfamily 1, Group F, Member 1/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 2/genetics* ; Nuclear Receptor Subfamily 1, Group F, Member 3/genetics* ; RNA, Messenger/genetics* ; Radiation Exposure ; Radiation, Ionizing ; Reproductive Physiological Phenomena/radiation effects* ; Sperm Motility/radiation effects* ; Spermatozoa/radiation effects* ; Testis/radiation effects*