Hypothalamic regulation of reproduction under the chronic influence of toluene and melatonin

Experiments on chronic administration of melatonin with and without chronic inhalation of toluene dosed at both maximal permissible concentration (50 mg/ml) and limited chronical range (500 mg/m3) have been carried out on female rats to discover their effects on biogenic amines system in hypothalamic structures related to gonadoliberin synthesis and secretion - preoptic area (PA) and median eminence (ME). Contents of biogenic amines in ME and especially in PA have been shown to have circadian variations with maximum in the morning in control group of rats.The chronic effect of synchronizing agent melatonin (administered dissolved in drinking water in concentration of 10 pg/m l, at night during 2 months) on neotransmitters and their circadian variations in both hypothalamic structures proved surprisingly to be much alike the effect of toluene. Both chemicals cause the disturbances of normal circadian variations o f norepinephrine, dopamine and serotonine in PA and dopamine in ME. The simultaneous administration of toluene and melatonin showed likewise no synchronizing ability of the latter under the conditions described.

Social Behaviour and Circadian Variations in Different Activities of Captive Hog Deer (Axis porcinus)

Management practices/strategies to re-modulate the wild behaviour of animal species could increase their number in natural areas. The captive herd of hog deer showed slight changes from wild behaviour due to captive stress with no alteration in wild behaviour pattern except captive stress. Adult males (6), adult females (6) and fawns (6) were selected and observed round the clock for thirty days across season after one-hour interval on each activity. All subjects in hotter part of the day spent more time in sitting and rest. While, few hours of night in sleeping, resting and rumination. Fawn spent more time in sitting, resting, and hiding compared to adults. During wandering, they also spent some time in standing. It was noticed that all hog deer in herd not slept together but few of them remain active. Only male fighting was observed and maximum was noticed in August and September during breeding season. Hog deer were mainly crepuscular in feeding with irregular short intakes, and grazing on grasses present in enclosure. This study provides guideline to rehabilitate wild hog deer for better breeding management, conservation and raising practices.

Circadian variations in the occurrence of first‐ever intracerebral hemorrhage from different sources of income: a hospital‐based cross‐sectional study

Background The onset time of intracerebral hemorrhage (ICH) may be closely related to the working style and living habits of people, which are determined by different income sources in China. Therefore, the purpose of our study was to investigate the Circadian Variations in the occurrence of ICH from different sources of income. Methods This retrospective study enrolled 4,327 patients with first-ever ICH. Based on the time of day at which the patients developed symptoms, the classifiable onset time was assigned to one of eight three-hour intervals. And based on different income sources, they were categorized into three groups: Farmers, Wage-earners, and Freelancers. Demographic and risk factors of patients were then summarized, and the circadian variation of the 3 groups of patients’ known time of onset and those stratified by sex and age were analyzed. Results The frequency of ICH onset exhibited significant circadian variation among the 3 income groups, demonstrating a bimodal distribution in the daytime, with a nadir during the night (all P < 0.001). Three groups showed a significant initial peak between 06:01 and 09:00, and the same peak was observed in their subgroups of sex and age. In the 3 income source groups, there was a smaller second peak that between 15:01 and 18:00 for Farmers and Wage-earners and 18:01 and 21:00 for Freelancers. After stratification by sex and age, the second peak was between 18:01 and 21:00 for female in Farmers, female in Freelancers, under 65 years of age in Wage-earners and 65 years or older in Freelancers, while 15:01 and 18:00 for the other groups. Conclusions Different circadian variations of ICH onset time are found in patients with different income sources in southwest China’s Chongqing Municipality cohort. Moreover, the frequency and distribution pattern of peak hours may be closely related to the working style and living habits of people with different income sources.

Circadian variation in renal blood flow and kidney function in healthy volunteers monitored with noninvasive magnetic resonance imaging

Circadian regulation of kidney function is involved in maintaining whole body homeostasis, and dysfunctional circadian rhythm can potentially be involved in disease development. Magnetic resonance imaging (MRI) provides reliable and reproducible repetitive estimates of kidney function noninvasively without the risk of adverse events associated with contrast agents and ionizing radiation. The purpose of this study was to estimate circadian variations in kidney function in healthy human subjects with MRI and to relate the findings to urinary excretions of electrolytes and markers of kidney function. Phase-contrast imaging, arterial spin labeling, and blood oxygen level-dependent transverse relaxation rate (R2*) mapping were used to assess total renal blood flow and regional perfusion as well as intrarenal oxygenation in eight female and eight male healthy volunteers every fourth hour during a 24-h period. Parallel with MRI scans, standard urinary and plasma parameters were quantified. Significant circadian variations of total renal blood flow were found over 24 h, with increasing flow from noon to midnight and decreasing flow during the night. In contrast, no circadian variation in intrarenal oxygenation was detected. Urinary excretions of electrolytes, osmotically active particles, creatinine, and urea all displayed circadian variations, peaking during the afternoon and evening hours. In conclusion, total renal blood flow and kidney function, as estimated from excretion of electrolytes and waste products, display profound circadian variations, whereas intrarenal oxygenation displays significantly less circadian variation.

Circadian Variations in the Occurrence of Intracerebral Hemorrhage from Different Sources of Income: A Hospital-Based Cross-Sectional Study

Background: The onset time of intracerebral hemorrhage (ICH) may be closely related to the working style and living habits of people, which are determined by different income sources in China. Therefore, our purpose was to investigate the Circadian Variations in the occurrence of ICH from different sources of income. Methods: This retrospective study enrolled 4,327 patients with ICH. Based on the time of a day at which the patients developed symptoms, the classifiable onset time was assigned to one of eight three-hour intervals. And based on different income sources, they were categorized into three groups: Farmers, Wage-earners and Freelancers. Characteristics and risk factors of patients were then summarized, and the circadian variation of three groups of patients’ known time of onset and those stratified by gender and age were analyzed.Results: The frequency of ICH onset exhibited significant circadian variation among the three income groups, demonstrating a bimodal distribution in the daytime, with a nadir during the night (all P < 0.001). Three groups showed a significant initial peak between 06:01 and 09:00, with a smaller second peak that between 15:01 and 18:00 for Farmers and Wage-earners and 18:01 and 21:00 for Freelancers. After stratification by gender and age, all demonstrated a bimodal distribution except women in Wage-earners and under 65 years of age in Wage-earners. Conclusions: Different circadian variations of ICH onset time were found in patients with different income sources in southwest China's Chongqing Municipality cohort. Moreover, the frequency and distribution pattern of peak hours were closely related to the working style and living habits of people with different income sources.