Association Between Mobile Phone Radiation Exposure and the Secretion of Melatonin and Cortisol,Two Markers of the Circadian System: A Review

The extremely important use of mobile phones in the world, at all ages of life, including children and adolescents, leads to significant exposure of these populations to electromagnetic waves of radiofrequency. The question, therefore, arises as to whether exposure to these radiofrequencies (RFs) could lead to deleterious effects on the body's biological systems and health. In the current article, we review the effects, in laboratory animals and humans, of exposure to RF on two hormones considered as endocrine markers: melatonin, a neurohormone produced by the pineal gland and cortisol, a glucocorticosteroid synthesized by the adrenal glands. These two hormones are also considered as markers of the circadian system. The literature search was performed using PubMed, Medline, Web of Sciences (ISI Web of Knowledge), Google Scholar, and EMF Portal. From this review on RF effects on cortisol and melatonin, it appears that scientific papers in the literature are conflicting, showing effects, no effects, or inconclusive data. This implies the need for additional research on higher numbers of subjects and with protocols perfectly controlled with follow‐up studies to better determine whether the chronic effect of RF on the biological functioning and health of users exists (or not). Bioelectromagnetics. 2021;42:5–17. © 2020 Bioelectromagnetics Society     

Effects of Radio-Collars are not Contingent on Socioecological Conditions in Degus

Species-specific research on free-ranging mammals reveals a diversity of effects of radio-collars on behavior, body condition, and fitness. Although these studies indicate rather limited direct effects, radio-collars may cause effects influenced by socio-ecological conditions. Using a 7-year study on a natural population of group-living degus (Octodon degus), we tested the hypothesis that ecological (food availability, burrow density) and social (group size, group male-to-female ratio) conditions modulate effects of radio-collars on body condition (e.g., body mass, ecto- and endoparasite loads, fecal cortisol metabolites) and direct fitness (litter size, adult survival). We determined the effect of radio-collar use on degus by contrasting the presence or absence of radio-collars, quantifying the effects of the number of days carrying a radio-collar, and the relative mass of radio-collars worn by degus in central Chile between 2009 and 2015. Radio-collar use was not associated with direct effects on litter size, adult survival, or with body mass and fecal cortisol metabolites but was linked to low ecto- and endoparasite loads. These seemingly positive effects may reflect decreased mobility, or a research bias for radio-collaring larger, healthier individuals. There was no evidence that ecological and social conditions modulated radio-collar effects on degu body condition and direct fitness. These findings are consistent with evidence from other mammal studies that reported no appreciable detrimental direct or indirect effects of radio-collars. © 2021 The Wildlife Society.     

超级马拉松运动中唾液α-淀粉酶活性和尿液糖皮质激素浓度的时程变化*

目的: 观察超级马拉松过程中唾液α-淀粉酶活性和尿液糖皮质激素浓度的时程变化。方法: 选取长期规律参加有氧训练的20名男性健康青年,年龄为(22.57±1.63)岁,身高(175.28±4.58)cm,体重(66.95±5.36)kg,完成一次36 h的超级马拉松(12 h～24 h休息),记录运动中R-R间期,分别在在0 h(运动开始前)、12 h(首日结束后)、24 h(次日开始前)、36 h(运动结束后)采集测试对象的唾液和尿液,采用碘-淀粉法检测唾液α-淀粉酶活性,采用液相色谱法检测尿液糖皮质激素浓度。结果: 与安静状态(0 h)相比,运动中的心率、运动后的过氧消耗和运动冲量值均显著增加(P＜0.05),其中,0-12 h的运动后的过氧消耗和运动冲量值显著高于24~36 h(P＜0.05)。与安静状态相比,12 h时唾液α-淀粉酶活性显著增加(P＜0.05),24 h时显著下降(P＜ 0.05);与24 h相比,36 h时显著增加(P＜0.05)。与安静状态相比,12 h、24 h和36 h时尿液中的皮质醇的浓度显著升高(P＜ 0.05),24 h时显著低于12 h和36 h(P＜0.05);可的松的浓度在运动过程中持续升高,且显著高于安静状态(P＜0.05)。结论: 人体唾液α-淀粉酶活性和尿液皮质醇浓度于运动后升高,休息后下降;尿液可的松浓度在运动过程中持续升高。     

The dark side of white hair? Artificial light irradiation reduces cortisol concentrations in white but not black hairs of cattle and pigs

Analysing hair cortisol concentrations (HCCs) is a minimally invasive way to retrospectively assess long-term stress, and its application in studies of animal welfare and stress has attracted considerable interest. However, not only stress-related effects but also hair-specific characteristics and external influences can affect HCCs and interfere with the interpretation of results. Thus, it was the aim of this study to investigate the impact of daylight and UV irradiation on cortisol concentrations in the hairs of pigs and cattle. We also examined whether a potential irradiation effect on HCCs depended on the colour of the hair. For this purpose, black and white hair samples from 18 Saddleback pigs and 18 Holstein Friesian cattle were exposed to artificial light (both visible and UV) and compared with control hair samples from the same animals kept in the dark. Exposure to artificial light significantly decreased HCCs in both pigs (P < 0.05) and cattle (P < 0.001), and hair colour had an influence on HCCs, with black hair showing higher cortisol levels than white hair (cattle: P < 0.001, pigs: P = 0.07). The interaction between light exposure and hair colour was significant in both pigs (P < 0.01) and cattle (P < 0.001), so light exposure reduced HCCs in porcine white hair but not black hair. In cattle, light-exposed white hair exhibited lower hair cortisol levels than control white hair or black hair. These results demonstrate that artificial light irradiation degrades hair cortisol or favours its elimination by structural changes of the hair matrix. However, this effect was only detectable in white hair, indicating that the melanin pigments in black hair absorbed radiation, thereby reducing the effects of photodegradation. Compared with other known influencing factors on HCCs, such as age and body region, the influence of light irradiation was relatively low in this in vitro experiment. However, further studies should investigate this influence under real-life animal conditions, such as outdoor and indoor housing.     

Excretion,Metabolism and Tissue Distribution of A Spin Trapping Agent, α-Phenyl-N-Tert-Butyl-Nitrone (Pbn) in Rats

The objective of this study is using radiolabelled PBN to determine the tissue distribution, excretion, and metabolism of PBN in rats in order to evaluate the effective time to trap free radical in appropriate tissue(s). Our results demonstrated that PBN is rapidly absorbed when it is injected intraperitoneally in the animal. PBN can be used as an effective spin trapping agent for a variety of tissues since it is evenly distributed among a wide range of tissues measured. Since there is no difference in the tissue concentrations and distribution pattern of PBN at 15, 30 and 60min after injection of PBN. it is appropriate to choose any of these time intervals to terminate the experiment and extract the spin adduct. The excretion of PBN, however, is slow. The majority of the radioactivity (70%) was excreted by the first 3 days. Only 5.7% of radioactivity was collected from 3 to 14 days. The remaining 25% of the radioactivity may be in the form of expired ¹⁴CO₂. Trace amounts of radioactivity were recovered in the feces. PBN has probably only one major form of metabolite excreted in the urine. A small amount of the parent compound, however, was also excreted in the urine. The chemical structure of the metabolite(s) is still unknown.     

Imbalanced estrogen metabolism in the brain: possible relevance to the etiology of Parkinson’s disease

Damage to DNA by dopamine quinone and/or catechol estrogen quinones may play a significant role in the initiation of Parkinson’s disease (PD). Depurinating estrogen–DNA adducts are shed from cells and excreted in urine. The aim of this study was to discover whether higher levels of estrogen–DNA adducts are associated with PD. Forty estrogen metabolites, conjugates, and DNA adducts were analyzed in urine samples from 20 PD cases and 40 matched controls by using ultra performance liquid chromatography/tandem mass spectrometry. The levels of adducts in cases versus controls (P?<?0.005) suggest that unbalanced estrogen metabolism could play a causal role in the initiation of PD.     

Seasonal Variation in Human Salivary Cortisol Concentration

Measurement of cortisol concentration can contribute important information about an individual's ability to adjust to various environmental demands of both physical and psychosocial origin. However, one uncertainty that affects the possibilities of correctly interpreting and designing field studies is the lack of observations of the impact of seasonal changes on cortisol excretion. For this reason, the month‐to‐month changes in diurnal cortisol concentration, the awakening cortisol response (ACR), maximum morning concentration, and fall during the day were studied in a group of 24 healthy men and women 32 to 61 yrs of age engaged in active work. On one workday for 12 consecutive months, participants collected saliva at four time points for determination of cortisol: at awakening, +30 min, +8 h, and at 21:00 h. Data were analyzed by a repeated measures design with month (12 levels) and time‐of‐day (4 levels) as categorical predictors. Cortisol concentrations were analyzed on a log scale. The diurnal pattern of cortisol was similar across months (interaction between month and time of day: p>0.4). The main effects of month and time‐of‐day were statistically significant (p <0.001). Highest concentrations were observed in February, March, and April, and lowest concentrations were observed in July and August. There were no statistically significant effects in any of the other measures, or between men and women. In conclusion, a seasonal variation in salivary cortisol concentrations was detected in an occupationally active population. Thus, seasonal variation needs to be taken into account when designing and evaluating field studies and interventions and when making comparisons across studies.     

Controlled Exposure to Light and Darkness Realigns the Salivary Cortisol Rhythm in Night Shift Workers

The efficacy of a light/darkness intervention designed to promote circadian adaptation to night shift work was tested in this combined field and laboratory study. Six full-time night shift workers (mean age ± SD:37.1 ± 8.1 yrs) were provided an intervention consisting of an intermittent exposure to full-spectrum bright white light (～2000 lux) in the first 6 h of their 8 h shift, shielding from morning light by tinted lenses (neutral gray density, 15% visual light transmission), and regular sleep/darkness episodes in darkened quarters beginning 2 h after the end of each shift. Five control group workers (41.1 ± 9.9 yrs) were observed in the presence of a regular sleep/darkness schedule only. Constant routines (CR) performed before and after a sequence of ～12 night shifts over 3 weeks revealed that treatment group workers displayed significant shifts in the time of peak cortisol expression and realignment of the rhythm with the night-oriented schedule. Smaller phase shifts, suggesting an incomplete adaptation to the shift work schedule, were observed in the control group. Our observations support the careful control of the pattern of light and darkness exposure for the adaptation of physiological rhythms to night shift work.