• Title/Summary/Keyword: circadian variation

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Effect of Circadian Rhythms on the Bromobenzene Metabolism in Rats (랫드에 있어서 주야 시차가 Bromobenzene 대사에 미치는 영향)

  • 김광진;신중규;윤종국
    • Toxicological Research
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    • v.13 no.4
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    • pp.377-383
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    • 1997
  • To investigate the circadian variation in the bromobenzene metabolism, bromobenzene(400 mg/kg body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Each group of animals was sacrificed at 8hr after last injection of bromobenzene. The contents of hepatic CYP were more increased in control rats of night phase than those of day phase but in case of bromobenzene treatment there were no differences in hepatic CYP between rats of the night phase and those of day phase and the injection of prednisolon inhibited the hepatic CYP content in rats. Furthermore, the decreasing rate of hepatic glutathione contents to the control was higher in rats of day phase than those of night phase by the bromobenzene treatment. And the hepatic glutathione S-transferase activities were increased both in control and bromobenzene treated rats of the night phase than those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content, serum levels of alanine aminotransferase were more increased both in bromobenzene-treated and control rats of the night phase than those in the day phase. These results indicate that the rats of night phase may induce more accelerated formation of bromobenzene 3,4-oxide from bromobezene than those of day phase in rats.

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Thermoregulatory Responses of AM & PM with Body Fat Rate at a Hot Environment (서열환경하에서 체지방률에 따른 오전과 오후의 체온조절반응)

  • Kim, Seong-Suk;Lee, Jung-Sug;Kim, Hee-Eun
    • Fashion & Textile Research Journal
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    • v.7 no.3
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    • pp.315-320
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    • 2005
  • With regard to the fact that temperature of human body remains almost constant at $37^{\circ}C$, changes by circadian variation, this study intended to investigate the effect of circadian rhythm on physiological responses of human body according to body fat rate. Fifteen healthy adult women were recruited for this study and were measured body fat as a method of bio impedance. We organized subjects into three groups ; low body fat group(group L-less than 20% of body fat), medium body fat group(group M-20%~30% of body fat) and high body fat group(group H-more than 30% of body fat). The experiment was carried out in a climate chamber of $32^{\circ}C$, 60% RH with the repeat of 'Exercise' and 'Rest' period. Subjects participated in two experiments, one is morning experiment(called 'AM'), the other is afternoon experiment (called 'PM'). The results of this study are as follows ; As to the variation of rectal temperature, group L and M had a significant difference in the time of the day between AM and PM, but group H had almost the same rectal temperature in the two kinds of experimental time. The reason why group H had a smaller difference in the circadian rhythm of rectal temperature in this study is estimated at the Budd et al.(1991)'s results that body fat had effects on reduction in thermogenesis, radiation, mean skin temperature, and increase in insulation of the tissues. Group M had the highest mean skin temperature in the 'PM'. All the 3 groups didn't have stable values in 'AM'. But it showed more stable in 'PM' than 'AM'. Sweat rate was the highest in group H in both 'AM' and 'PM'. Group M had larger sweat rate in 'PM' than 'AM'. but in group L and H, sweat rate was almost the same in two kinds of time of the day. This result suggests that who have more or less body fat have larger difference in sweat rate between morning and afternoon than who have normal body fat.

Molecular Analysis of Growth Factor and Clock Gene Expression in the Livers of Rats with Streptozotocin-Induced Diabetes

  • Kim, Joo-Heon;Shim, Cheol-Soo;Won, Jin-Young;Park, Young-Ji;Park, Soo-Kyoung;Kang, Jae-Seon;Hong, Yong-Geun
    • Reproductive and Developmental Biology
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    • v.33 no.3
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    • pp.163-169
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    • 2009
  • Many biological systems are regulated by an intricate set of feedback loops that oscillate with a circadian rhythm of roughly 24 h. This circadian clock mediates an increase in body temperature, heart rate, blood pressure, and cortisol secretion early in the day. Recent studies have shown changes in the amplitude of the circadian clock in the hearts and livers of streptozotocin (STZ)-treated rats. It is therefore important to examine the relationships between circadian clock genes and growth factors and their effects on diabetic phenomena in animal models as well as in human patients. In this study, we sought to determine whether diurnal variation in organ development and the regulation of metabolism, including growth and development during the juvenile period in rats, exists as a mechanism for anticipating and responding to the environment. Also, we examined the relationship between changes in growth factor expression in the liver and clock-controlled protein synthesis and turnover, which are important in cellular growth. Specifically, we assessed the expression patterns of several clock genes, including Per1, Per2, Clock, Bmal1, Cry1 and Cry2 and growth factors such as insulin-like growth factor (IGF)-1 and -2 and transforming growth factor (TGF)-${\beta}1$ in rats with STZ-induced diabetes. Growth factor and clock gene expression in the liver at 1 week post-induction was clearly increased compared to the level in control rats. In contrast, the expression patterns of the genes were similar to those observed after 5 weeks in the STZ-treated rats. The increase in gene expression is likely a compensatory change in response to the obstruction of insulin function during the initial phase of induction. However, as the period of induction was extended, the expression of the compensatory genes decreased to the control level. This is likely the result of decreased insulin secretion due to the destruction of beta cells in the pancreas by STZ.

Circadian variation of IV PCA use in patients after orthognathic surgery - a retrospective comparative study

  • Park, Sookyung;Chi, Seong In;Seo, Kwang-Suk;Kim, Hyun Jeong
    • Journal of Dental Anesthesia and Pain Medicine
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    • v.15 no.3
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    • pp.141-146
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    • 2015
  • Background: An understanding of the features of postoperative pain is essential for optimal analgesic dosing strategies. Using a visual analogue scale (VAS) score and patient controlled analgesia (PCA) infusion pattern analysis, an anesthesiologist can estimate when and how severely patients suffer from pain. Several reports have been published about circadian changes in the pain threshold. Postoperative pain was analyzed retrospectively in 250 patients who underwent orthognathic surgery. Methods: A total of 250 patients were allocated into two groups according to the time of recovery from anesthesia. Patients in the early group (group E) recovered from anesthesia before 06:00 p.m. Patients in the late group (group L) recovered from anesthesia after 06:00 p.m. All patients received intravenous patient controlled analgesia (IV PCA) at the end of the operation. The VAS score of pain intensity was measured. Self-administration of bolus analgesic from the IV PCA device was also analyzed according to actual time and elapsed time. Results: VAS scores showed no difference between the two groups except 36 hours after recovery from anesthesia. On POD1, there were two peaks for self-administration of bolus analgesics in group L and one peak in the morning for group E. Two peaks each in the morning and in the afternoon were shown in both groups on POD2. Conclusions: Diurnal variance in pain should be considered for effective dosing strategies.

Effect of Circadian Rhythms on the Xylene Metabolizing Enzyme Activities in Rats (Xylene 대사 효소 활성에 미치는 주.야 시차의 영향)

  • 이혜자;윤종국
    • Journal of Environmental Health Sciences
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    • v.27 no.2
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    • pp.10-16
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    • 2001
  • To evaluate an effect of circadian variation on the xylene metabolizing enzyme activities, 50% m-xylene in olive oil(0.25 $m\ell$/100g body weight) was intraperitoneally administered to the rats every other day for 6 days both in the night; 24:00 and the day; 12:00. Then animals were sacrigiced at 8hr after last injection of m-xylene. Hepatic microsomal cytochrome p450 contents were more increased both in control and xylene treated rats of night phase than those of day phase. But the activity of hepatic alcohol dehydrogenase(ADH) in control of night phase showed the similar value with that in those of day phase and xylene treated rats of day phase showed an increasing tendency of hepatic ADH activity as those of night phase showing similar activity. Furthermore, control rats of night phase than those of day phase. And by xylene treatment, enzyme activities of rats of day phase were higher tendency in rats of control but those of night phase were somewhat inhibited. Besides, xylene-treated animals of night phase showed increasing tendency of urinary methylhippuric acid concentration compared with those of day phase. On the other hand, liver weight per body weight(%), hepatic lipid peroxide content and serum xanthine oxidase activity were higher in night phase. And the activities of hepatic oxygen free radical metabolizing enzymes such as xanthine oxidase, gluthathione S-transferase, and xylene-treated rats of night phase than those of day phase. In conclusion, it can be hypothesized on the basis of the results that the accumulation rate of m-xylene intermediate metabolite, i.e. m-methylbenzaldehyde in liver tissus may be higher in night phase than in day phase and it may be responsible for higher liver toxicity in bight phase than in day phase.

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Serum cortisol concentrations on the normal condition in Korean native goats by ELISA (ELISA에 의한 국내 재래종 산양의 정상상태에서의 혈중 cortisol 농도)

  • Cho, Kyu-woan;Hur, Ju-hyeong;Lee, Eun-sug;Kang, Chung-boo
    • Korean Journal of Veterinary Research
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    • v.33 no.4
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    • pp.711-717
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    • 1993
  • This study was performed to examine the charges of serum cortisol concentrations on the normal conditions in Korean native goats by enzyme-linked immunosorbent assay(ELISA). The Korean native goats were 4 to 30 months old and weighted 6.0 to 28kg. The goats were allowed ad libitum access to water and food. To minimize the stress with handing and blood sampling, animals were adapted for 2 weeks before the experiment. After adaptation, intravenouse catheter was inserted left intact a jugular vein of 6 goats and blood samples were done 2~3 days later. Experimental animals were divided into 2 groups which was non-catheterized and catheterized group in order to examine the effect for changes of serum concentration and circadian rhythm of cortisol. The results were obtained as follows ; The sensitivity of serum cortisol concentration was $20pg/m{\ell}$. The intra-assay and inter-assay coefficient of variation were below 2.5% and 5%, respectively. Serum concentration of cortisol was more higher in noo-catheterized group$(32.84{\pm}16.78ng/m{\ell})$ than catheterized group$(23.20{\pm}10.29ng/m{\ell})$. The difference according to months old in serum concentration of cortisol was the more higber on 4~6 than 7~12 and lowest over 12 months old. A circadian rhythm in the serum concentration of cortisol in Korean native goats was not found significantly with 2 hours sampling intervals.

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Subjective Sleep Characteristics and Depression of shift Nurses (교대근무 간호사의 주관적 수면특성과 우울성향)

  • Jeong, Sook Hee
    • Korean Journal of Occupational Health Nursing
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    • v.7 no.2
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    • pp.155-163
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    • 1998
  • In order to investigate the effects of rotating shift work on the subjective characteristics of sleep and mental depression questionnaire survey was carried out on 405 shift workers and 153 nonshift workers who were nurses employed. in three university hospital. The questionnaire forms used in this study were the self rating depression scale(SDS) and circadian type questionnaire(CTQ) factor R(rigidity/flexbility of sleeping habit) and factor V(inability/ability to overcome drowsiness). The results were as follows ; 1. Mean score of CTQ R in shift workers was significantly lower than that in nonshift workers, however, no significant difference in CTQ V was observed between two groups. 2. Mean score of SDS was significantly higher in shift workers(44.1) than in nonshift workers(39.8). 3. Mean self rating depression scale scores of pervasive affect, physiologic equivalents and psychological equivalents were significantly higher in shift workers than in nonshift workers. 4. In shift worker, mean SDS score was the highest in confusion and followed by diurnal variation, retardation, and indeciveness in the descending order. In nonshift worker, that score was the highest in decreased libido and followed by confusion, and indeciveness in the descending order. 5. Circadian type questionnaire scores was significantly and negatively correlated with significantly and negatively correlating with Self-rating depression scale scores(r=-0.473).

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Effects of Photoperiod Treatment on Histological Changes in Testis Tissues of the Golden Hamster

  • Kang, Jae-Won;Kim, Seol-Ah;Park, Chang-Eun
    • Korean Journal of Clinical Laboratory Science
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    • v.44 no.1
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    • pp.31-37
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    • 2012
  • Many mammals in temperate zones are affected by the distinctive changes of the four seasons in these zones. Their reproductive status is active in the summer climate and inactive during severe winter weather. The golden hamster (Mesocricetus auratus) is seasonal breeding animal whose sexual activities are regulated by photoperoidism. The reproduction and metabolism are activated by long summer days (LD) and inhibited by short winter days (SD). After several months of SD, animals become refractory to this inhibitory photoperiod and spontaneously revert to LD-like physiology. The suprachiasmatic nuclei (SCN) house the primary circadian oscillator in mammals. Seasonal changes in the photic input to this structure control many annual physiological rhythms via SCN-regulated pineal melatonin secretion, which provides an internal endocrine signal representing photoperiod. The aim of this study was to assess the variation in the morphology of the testis in relation to the natural photoperiod in male golden hamsters. The hamsters were castrated at different weeks (2, 5, 8, and 15). The cell numbers of tubules with spermatogonia (SG), spermatocyte (SC), spermatids (ST), and spermatozoa (SZ) were recorded in each sample. The results showed that testicular regression of golden hamsters occurred in the SD-treated animals. The present investigation determines that the effects of the photoperiod on the reproduction of male golden hamsters. It was also found that the circadian period increases the rate of reproductive inhibition in animals exposed to inhibitory photoperiods.

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Circadian DNA-synthetic Rhythm Accompanied Mitotic Rhythm in Newly Hatched in Chicken Liver : Possible Role of Feeding Regiment (사료섭취가 병아리의 간세포증식 리듬에 미치는 영향)

  • Han, Joon-Pyo
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.18 no.4
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    • pp.444-448
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    • 1989
  • The division and circadian DNA-synthesis rtythm are studied in chick liver immediately after hatching. The vision function is tested by the mitotic and the $^3H-thymidine$ labelling index The DNA synthesis exhibited a cyclic variation of 12 hours immediately after hatching. The rhythmic changes of DNA synthesis was maintained in the liver of meal-fed chickens, but the DNA synthetic activities decreased gradually in the starved chicken liver. From this time, the rhythm of DNA synthesis was greatly afffected by lighting schedule, all these DNA synthesis of chicken liver was accompained by mitosis.

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