Male Rhythm Research Articles

Serum soluble mediator waves and networks along healthy ageing.

The ageing process is a complex phenomenon that impacts the immune system, leading to changes in the pattern of serum soluble mediators. In the present study, the serum levels of several chemokines, pro-inflammatory/regulatory cytokines and growth factors were quantified by high-throughput microbeads array in serum samples from 541 healthy subjects at distinct age ranges (3Yrs to >70Yrs). A broad increase in serum soluble mediators was observed at 6-10Yrs with subsequent decline at 11-20Yrs and 21-30Yrs followed by a second round of upregulation starting at 31-40Yrs, with a large increase at 51-60Yrs and a marked decline at age >70Yrs. Heatmap and signatures of serum soluble mediators demonstrated a bimodal profile with one peak at 6-10Yrs and a second wave around 61-70Yrs. A universal decline was observed later at age >70Yrs. In males, the second wave started earlier at 31-40Yrs with a peak at 51-60Yrs and a further smooth decline towards >70Yrs. Conversely, in females, the first peak extended from 3-5Yrs to 6-10Yrs and the second wave starting around 41-50Yrs with a peak at 61-70Yrs followed by a sharp decline at >70Yrs. Overall, CCL11, CXCL8, IL-1β, IL-6 were underscored as universal age-related biomarkers with higher levels observed at later age ranges (after 31-40Yrs) and TNF with increased levels starting at early age ranges. Data analysis demonstrated that the highest neighborhood connectivity amongst soluble mediators occurred at 3-5Yrs, with distinct declining and strengthening rhythm in males and females. Notably, rebuilding re-arrangements were usually earlier and more frequent in females (at 11-20Yrs, 51-60Yrs and >70Yrs) than in males (at 21-30Yrs, 61-70Yrs). Overall, this study provided a comprehensive landscape of evidence portrayed by distinct waves, rhythms and dynamic network connectivity along healthy ageing with differences in magnitude and timing reported for sexes.

GENDER-SPECIFIC DIFFERENCES OF CARDIAC VEGETATIVE CONTROL IN ADRENALINE-INDUCED NECROSIS AND LIGHT DEPRIVATION

Background. Cardiovascular disease is the main cause of morbidity predominantly in males. Stress is one of the crucial factors, especially with light desynchronosis. Objective of the study was to assess gender-specific characteristics of cardiac vegetative control in myocardial necrosis in cases of light deprivation. Methods. Cardiac vegetative control in adrenaline-induced myocardial necrosis (AIMN) in a setting of light deprivation (LD) was assessed in 72 mature white rats of both sexes. The animals were divided into 2 groups: G1 – the animals kept under day/night cyclic balance (12 hours/12 hours); G2 – the animals kept at LD (illumination 0.5-1 LX) for 10 days. On Day 11, AIMN caused by adrenaline (0.5 mg/kg) and heart rate variability (HRV) was assessed in 1 hour and 24 hours. Results. The development of AIMN at LD in the ♂G2 led to HRV increase that was caused by augmentation of parasympathetic and reduction of sympathetic cardiac effects. In cases of AIMN, changes of CVC in the ♀G2 were similar to the ♀G1. However, in 1 hour of AIMN, parasympathetic cardiac effects were more significant than in the ♀G1. While the ♀G2 AIMN animals experienced balanced sympathetic and parasympathetic actions, the predominance of the sympathetic component was evidenced in the ♀G1 AIMN animals. Conclusions. Light deprivation has different effects on baseline sympathetic/parasympathetic balance in males and females, i.e. increased parasympathetic control of heart rhythm in males and maintenance of sympathetic/ parasympathetic balance in females.

Effect of age, gender and exercise on salivary dehydroepiandrosterone circadian rhythm profile in human volunteers

There has been a lot of effort by scientists to elucidate the multi functions of the naturally occurring hormone, dehydroepiandrosterone (DHEA). However, to plan research experiments optimally, it is important first to characterize the diurnal rhythm in healthy individuals. The aim of this research was to investigate the daily circadian rhythms of DHEA among the 2 genders, and the effect of age and exercise on salivary DHEA circadian rhythms. Volunteers (20–39 and 40–60years) were recruited for 2 studies investigating the salivary DHEA circadian rhythm. The first study looked at the effect of gender and age on DHEA levels on 2 non-consecutive days, and the second study explored the effect of exercise on DHEA circadian rhythm in males. DHEA levels were estimated by a sensitive and specific ELISA method. The results showed a clear daily circadian rhythm in salivary DHEA in all participants groups, however the profile was flatter in the older female group. There was a significant difference between age and gender groups particularly at 8.00h. In young males DHEA reduced from 541.1±101.3 (mean±sd) at 8.00h to 198.9±90.7pg/mL at 18.00h; p<0.0001, and young females from 401.6±149.5 to 215.4±95.3pg/mL; p<0.001. In older males DHEA reduced from 267.5±32.4 to 132.5±46.7pg/mL; p<0.001, and older females from 147.7±78.1 to 89.5±29.1pg/mL; p=0.05. DHEA levels on 2 non-consecutive days showed some variations but this was not significant. Aerobic exercise has significantly increased DHEA levels at 2 time points of the day (p=0.05) in male subjects. In conclusion, our study showed a clear daily circadian rhythm in salivary DHEA in all participants was observed, but the profile was flatter in the older groups.

Circadian rhythm in males of Aegla schmitti (Decapoda, Anomura, Aeglidae) under laboratory conditions

A study of the daily activity pattern of male Aegla schmitti was carried out in the laboratory. Animals were acclimated in aquaria with a water temperature of 18.5 °C and a photoperiod of 12:12 (day/night) for seven days. Two experiments were then performed. The first consisted of observing animals during the daytime when subjected to a natural photoperiod (NP); the second consisted of observing animals during the daytime hours but in the dark, whilst they were living under an inverted photoperiod (RP). The animals spent more time in active behaviors in the light and the time spent in these behaviors decreased during the night. By contrast, swimming and grooming showed peaks at 9:00 pm and midnight. This study is the first to evaluate the biology of behavioral aspects of A. schmitti, providing valuable information about feeding habits, mechanisms and patterns of agonistic activity in this crustacean family.

Rhythmic male reproductive behavior controls timing of courtship and mating in Laupala cerasina

In many organisms, mating behavior occurs at a particular time of day, which may be important for avoiding mate competition or interspecific mating. Crickets of the Hawaiian genus Laupala exhibit an unusually protracted courtship in which males produce a series of nuptial gifts prior to the species-typical time of mating. Mating time is one of several rhythmic behaviors that have diverged among closely related Laupala species, which exhibit an extremely high speciation rate. Mating rhythm may reflect direct selection on male and/or female sexual receptivity or the pleiotropic consequence of selection on other rhythmic behaviors. To examine the role of sexual rhythmicity in Laupala cerasina, we characterized the time boundaries or “circadian gate” of courtship and mating, as well as female phonotactic response to male song. We also examined which sex is responsible for mating rhythmicity by phase-shifting males relative to the female photophase. Our results demonstrate that mating behavior is gated by the end of the light phase. Time limits to female mating receptivity were not observed and thus male rhythm alone appears to be responsible for the timing of mating. Furthermore, when courtship is initiated later in the day, males produce fewer nuptial gifts and increase nuptial gift production rate while delaying mating, suggesting that the number of gifts a female receives is important to male reproductive success.

Prognostic value of delayed and non-homogeneous ventricular repolarization and decreased variability of cardiac rhythm in males with arterial hypertension (clinical population study)

The increased duration and dispersion of the QT-interval and the depressed variability of cardiac rhythm have been recently considered to be predictors of life-threatening ventricular arrhythmias and sudden death. However. the prognostic value of these indices in patients with arterial hypertension (AH) is little studied. Three representative samples from the total population of 2167 males aged 25-64 years were examined by conventional epidemiological methods within the framework of the WHO "MONICA" project. In a group of patients with AH (n = 415), fatal cardiovascular events were studied for 9,5 years. Resting ECG was blindly evaluated according lo the Minnesota code and the duration of the QT and QTc intervals, their dispersion were manually determined on the basis of 12 standard leads (DQT and DQTc), heart rate, and its variability (SDNN). The prognostic value of threshold indices (QTc ≥ 440 msec 1/2 DQT ≥ 60 msec, DQTc ≥ 60 msec 1/2 and SDNN ≤ 20 msec) was studied by the survival methods: the Cox model, the Log-rant-test, and the Kaplan-Meier curves. In the total male population. AH is associated with the relative increase in the duration and dispersion of QT interval, with accelerated sinus rhythm, and its decreased variability. In the group of males with AH, these electrophysiological changes identify individuals at high risk for cardiovascular death irrespective of age, body mass index, blood pressure, smoking, alcohol abuse, blood lipid levels, the presence of coronary heart disease and left ventricular hypertension.

Sexual differences in 5′-deiodinase activity in the harderian gland of Syrian hamsters and the effect of pinealectomy: Regulation by androgens

Sexual differences on thyroxine 5′-deiodinase (5′-D) in the Harderian gland of Syrian hamsters were investigated. We compared the 24-h profile of 5′-D activity in male and female hamsters, observing a clear rhythm in males but not in females. Female values were always significantly higher than male ones. After pinealectomy day/night variations in male 5′-D activity at the time points studies were abolished, results that are in correlation with serum thyroid hormones. We also studied the regulation by androgen of the enzyme activity. Basal 5′-D activity increased in castrated males and levels fell when animals were implanted with testosterone or its product 5α-dihydrotestosterone (DHT). Female 5′-D activity was also inhibited by androgens. As only the addition of DHT in the presence of epitestosterone, an inhibitor of the conversion of testosterone on DHT, in castrated males was able to decrease 5′-D activity to control animal levels, we suggest a probable direct effect of DHT by itself. © 1996 Wiley-Liss, Inc.

Sexual differences in 5′‐deiodinase activity in the harderian gland of Syrian hamsters and the effect of pinealectomy: Regulation by androgens

Sexual differences on thyroxine 5′-deiodinase (5′-D) in the Harderian gland of Syrian hamsters were investigated. We compared the 24-h profile of 5′-D activity in male and female hamsters, observing a clear rhythm in males but not in females. Female values were always significantly higher than male ones. After pinealectomy day/night variations in male 5′-D activity at the time points studies were abolished, results that are in correlation with serum thyroid hormones. We also studied the regulation by androgen of the enzyme activity. Basal 5′-D activity increased in castrated males and levels fell when animals were implanted with testosterone or its product 5α-dihydrotestosterone (DHT). Female 5′-D activity was also inhibited by androgens. As only the addition of DHT in the presence of epitestosterone, an inhibitor of the conversion of testosterone on DHT, in castrated males was able to decrease 5′-D activity to control animal levels, we suggest a probable direct effect of DHT by itself. © 1996 Wiley-Liss, Inc.

Persistent Alteration of Pituitary-Adrenal Function in the Rat by Prepuberal Corticosterone Treatment

The possible existence of periods of sensitivity to elevated levels of corticosterone in the postnatal development of the pituitary-adrenal axis was investigated. Long-Evans rats were implanted ip with corticosterone (25 mg/100 g body wt) mixed with an equal amount of cholesterol on postnatal days 3, 6, 12 or 18. Eight blood samples were obtained from each animal at various ages by cardiac puncture. Steroid treatment during the first postnatal week resulted in lowered adult basal levels of plasma corticosterone without affecting the diurnal rhythm. Males treated on day 3 had lowered peak (PM) and trough (AM) levels of the steroid as adults, while males treated on day 6 showed only a lowered PM level. A similar reduction in basal levels of plasma corticosterone was observed in immature females, but did not persist into adulthood. Steroid treatment at day 12 had no effect on basal or diurnal pituitary-adrenal activity. Treatment at day 18 reduced the amplitude of the adult diurnal rhythm in both sexes and delayed the onset of the rhythm in males. No differences in stress responsiveness or adrenal weights were detected. Thus, two distinct periods exist in the postnatal development of the rat during which basal and diurnal pituitary-adrenal activity can be differentially and persistently altered by treatment with the naturally occurring glucocorticoid.