Twenty-four-Hour Rhythmic Variations of Histamine in Human Female Blood

We have previously observed that blood histamine levels undergo rhythmic 24 hour variations in male normal subjects. In the present study we examined whether similar 24 hour modifications were also present in female subjects. To this purpose, 60 healthy cycling women were enrolled for a chronobiological transverse study. To achieve experimental conditions as homogeneous as possible, the study was carried out on the first day of the menstrual flow. Histamine was determined in whole venous blood by a spectrophotofluorimetric method. The blood histamine levels showed significant rhythmic changes depending on the time of blood sampling, with 1 maximum and 1 minimum within a period of 24 h, with percentage rhythm 15.1, MESOR 0.15 μg/ml, amplitude 0.02 μg/ml and acrophase at 01:20 h. These results reveal the presence of 24 h cyclic variations of histamine levels in the female, as it occurred in male. However, the differences observed in the chronobiological rhythms of histamine between the two sexes may represent a peculiar feature of the first day of the menstrual cycle.     

Circadian variations of serum sex hormone binding globulin binding capacity in normal adult men and women

Diurnal variations of serum sex hormone binding globulin (SHBG), testosterone (T) and estradiol (E2) in five normal adult men and five normal adult women were investigated. SHBG binding capacity was measured by both polyacrylamide gel electrophoresis and dextran-coated charcoal technique (DCC); T and E2 were assayed by RIA and free T and free E2 were determined by means of equilibrium dialysis. In male subjects the variations of SHBG binding capacity was associated with the changes of total T, free T and T/SHBG index, which had the highest concentrations in the morning and the lowest levels in the evening during the 24 h test period, but percentage free T remained unchanged. Serum protein concentrations did not change significantly during 24 h. No significant diurnal changes of SHBG binding capacity, total E2, free E2, percentage free E2 and percentage free T were found in female subjects in the mid-luteal phase of the menstrual cycle, although significant fluctuations of total T, free T and T/SHBG index were observed throughout the day. The results suggested that SHBG may play a buffer role in the presence of fluctuations of testosterone production during 24 h period, allowing stabilization of a bioactive fraction of the hormone both in normal adult male and female. However, the concentrations of T in normal adult women may be too low to drive any change of SHBG levels while there were no significant variations of E2 throughout a day in the mid-luteal phase of the menstrual cycle.     

Cyclic changes of plasma spermine concentrations in women

Based on previous studies which suggest that blood polyamines fluctuate during the menstrual cycle, the present study was set to determine whether plasma concentrations of the polyamine spermine show menstrual cycle-associated changes and if so, how these changes relate to phasic variations in other female hormones. Blood samples were collected from a group of 9 healthy women of various ages at 5 defined periods during their menstrual cycle including 1 woman on oral contraceptives. Spermine concentrations were determined in plasma acid extracts by reversed-phase high performance liquid chromatography method. Plasma estradiol, LH and FSH were measured by microparticle enzyme immunoassay using an automatic analyzer. Spermine concentrations, 104.4 +/- 12.2 nmol/ml at 1-3 day of the cycle, were increased transiently with a peak (263.8 +/- 22.1 nmol/ml) at 8-10 day and declined to 85.4 +/- 29.8 nmol/ml by 21-23 day of the cycle. The peak spermine concentrations coincided with the first increase in plasma estrogen levels. The individual variations in the temporal profile of spermine concentrations were of similar magnitude as individual differences in other female hormones. We conclude that: a) Plasma spermine concentrations undergo distinct cyclic alterations during the menstrual cycle with peak concentrations coinciding with the first estradiol increase, and b) Peak plasma spermine concentrations occur during the follicular phase, just prior to ovulation, during the period of rapid endometrial growth.     

Menstrual induction by the vaginal application of ICI 81008 gel

After ～2 weeks menstrual delay (positive Pregnosticon Tests) “menstrual induction” was attempted in 75 gravidas by repeated vaginal application of a gel, containing 200 or 400 μg/ml ICI 81008. After ～10 minutes, following the 1st vaginal delivery of 400 μg ICI 81008, the uterus responded to this PGF2α analogue with sustained contracture. The highest success rate in induced bleeding (93%) and pregnancy termination (79%), without supportive therapy, was achieved when 400 μg ICI 81008 was administered 2 to 5 times at 4 hour intervals. Those gravidas (21%), who failed in induced menstruation, or stopped bleeding within 24 hours after treatment, had positive Pregnosticon Tests on day 14 and were curetted. The side effects, mostly vomiting and increased blood pressure, were transient and subjectively and medically acceptable. While the vaginal application of the drug is apparently less effective than the intrauterine (1), it has the advantage of simple delivery and the potential of self-administration.     

Plasma cortisol in cattle: Circadian rhythm and exposure to a simulated high altitude of 5,000 m

After a 2 week control period at 400 m, cattle were exposed to 5,000 m simulated altitude for 2 weeks, which was followed by a 2-week post-altitude control period. Plasma cortisol values from blood samples taken every 30 min for a total of 24 h indicated that cortisol was secreted episodically and that a circadian rhythm existed. When cortisol values were grouped into 4, 6-h periods, plasma cortisol was most abundant from 06:00 to 12:00 h with an average of 0.96µ g/100 ml and least abundant from 00:30 to 06:00 h with an average of 0.55µ g/100 ml. Plasma cortisol increased from 0.42 to 3.08µ g/100 ml during the 4 h ascent to 5,000 m and decreased to near normal levels the following day. A rhythmic plasma cortisol pattern was maintained after one day at simulated high altitude.     

Chronic intravenous infusion of noradrenaline produces labile hypertension in conscious rats

Nonadrenaline was infused intravenously for 5 days into conscious, unrestrained normotensive rats. Infusion of 40 μg per kg body weight per hour caused a chronic elevation of blood pressure, reaching a maximum increase of 28 ± 5 mm Hg on the fifth day. This hypertension is characterized by a labile blood pressure: periods of normotension are followed by rapid outbursts of hypertension. Resting plasma levels of noradrenaline ranged from 0.20–1.25 ng/ml. Infusion of 40 μg per kg body weight per hour caused a 4–5 fold increase. These observations suggest that chronic elevations of plasma noradrenaline are associated with labile hypertension.     

Effect of ibuprofen on menstrual blood prostaglandin levels in dysmenorrheic women.

In a randomized crossover study 15 dysmenorrheic women were treated during two consecutive menstrual period, once with the potent prostaglandin-synthesis inhibitor: ibuprofen and once with an identical looking placebo. Each patient was medicated for 12 hours during the first day of her menstrual flow and was subsequently fitted with a cervical cup for the collection of menstrual blood during three hours. In these samples the concentrations of prostaglandin (PG)F and PGE were measured by radioimmunoassay. The patients receiving placebo had high PGF levels 135 +/- 27 ng/ml (Mean +/- S.E.) which were significnatly reduced by Ibuprofen to 24 +/- 5 ng/ml (P less than 0.001). The PGE concentrations decreased from 5 +/- 1 ng/ml to 2 +/- 1 ng/ml (P less than 0.05). Ibuprofen also reduced the menstrual pain significantly (P less than 0.001). These results substantiate the earlier conclusion that a causal relationship exists between effective treatment with PG-synthesis inhibitors and decrease in menstrual blood PG levels, intrauterine pressure and dysmenorrheic pain.     

纳米硒通过抗氧化应激调节大脑NO含量改善睡眠剥夺小鼠认知功能

研究了纳米硒对睡眠剥夺(SD)小鼠(Mus musculus)认知功能的影响,并探讨其作用机制。将120只雄性昆明小鼠随机分成两批,第一批24只分为3组:对照组(NC)、亚硒酸钠组(SE)和纳米硒组(NS),分别给予硒浓度为4μg/ml的亚硒酸钠和纳米硒溶液每只0.5ml/d,NC组给等体积蒸馏水,连续30d,第31天测定SE和NS两组小鼠的血硒及全血GSH-Px活性,评价两种硒源的生物利用性;第二批96只分为4组:对照组(N-SeC),纳米硒低、中、高剂量组(L、M、H),L、M和H组分别给予硒浓度为2μg/ml、4μg/ml、8μg/ml的纳米硒溶液每只0.5ml/d,N-SeC组给予同体积蒸馏水,连续30d。第二批小鼠每组又各自分为4小组:SD对照组(SDC)及SD18h、SD36h、SD54h组,采用单平台水环境法(SPM)制作小鼠SD模型。在SD后,N-SeC、L、M和H组利用Y-型迷宫试验测定认知能力,同时测定小鼠大脑GSH-Px、NO、MDA含量。结果表明,纳米硒对GSH-Px活性的提高优于传统硒源亚硒酸钠,但血硒无显著差异;与SDC组比较,SD降低了小鼠的认知能力及大脑GSH-Px活性,提高了NO和MDA含量;与N-SeC比较,纳米硒使SD小鼠的认知功能得到改善,大脑GSH-Px活性提高,MDA和NO含量下降。上述结果表明,纳米硒能够改善SD小鼠的认知功能,这可能与其提高大脑GSH-Px活性并降低了自由基对大脑神经的损害有关。     

Effect of ibuprofen on menstrual blood prostaglandin levels in dysmenorrheic women

In a randomized crossover study 15 dysmenorrheic women were treated during two consecutive menstrual periods, once with the potent prostaglandin-synthesis inhibitor: ibuprofen and once with an identical looking placebo. Each patient was medicated for 12 hours during the first day of her menstrual flow and was subsequently fitted with a cervical cup for the collection of menstrual blood during three hours. In these samples the concentrations of prostaglandin (PG)F and PGE were measured by radioimmunoassay.The patients receiving placebo had high PGF levels 135 ± 27 ng/ml (Mean ± S.E.) which were significantly reduced by Ibuprofen to 24 ± 5 ng/ml (P<0.001). The PGE concentrations decreased from 5 ± 1 ng/ml to 2 ± 1 ng/ml (P<0.05). Ibuprofen also reduced the menstrual pain significantly (P<0.001). These results substantiate the earlier conclusion that a causal relationship exists between effective treatment with PG-synthesis inhibitors and decrease in menstrual blood PG levels, intrauterine pressure and dysmenorrheic pain.     

Hemolymph lipids and flight activity in Helicoverpa zea (Boddie) (lepidoptera: Noctuidae)

In this study the flight activity of female and male Helicoverpa zea (Boddie) moths was observed and compared to hemolymph lipid concentrations. The major male and female H. zea flight activity occurred between simulated dusk (1700) and dawn (0300). Male flight activity was up to 7 times greater than females through 6 days after eclosion except for the 1st day (0.8 times). Females had a unimodal pattern of flight activity, peaking between dusk and 2 h later. Males had a bimodal pattern; one between dusk and 2 h later, and another 3 h after dusk, continuing for h. Prior to dusk, total neutral hemolymph lipids (neutral) of H. zea day 4 moths was 64 μg/μl for males and 48 μg/μl for females. Typical lipid composition in day 4 males prior to flight was 1,2-diacylglycerides (DG) (50% w/w), triacylglycerides (TG) (35%), cholesterol esters (2%), and less than 1% monoacylglycerides and cholesterol. The remainder consisted of free fatty acids (<0.5 μg/μl), and various uncharacterized phospholipids and lipophilic compounds. Hemolymph DG concentration patterns were similar between day 4 males and females, were highest in both sexes prior to, during, and after flight (approximately 32 μg/μl), and then decreased steadily throughout the flight period to approximately 16 μg/ml as flight ceased. Hemolymph TG were lower than DG, but followed the same pattern except at 2100 and 2300. In day 4 males between 2100 and 2300, TG increased to 33 μg/μl which was when DG was lowest (15 μg/μl) and their flight activity was highest. Hemolymph DG decreased (26 to 20 μg/μl) in day 4 females between 2100 and 2300 as TG remained fairly constant (18 μg/μl).     

Measurement of 6-hydroxymelatonin in human urine and its diurnal variations

A gas chromatographic-mass spectrometric assay has been developed and applied to the measurement of the major melatonin metabolite in human urine. In seven normal adult male subjects, the mean daily urinary conjugated 6-hydroxymelatonin was 15.5 μg (6.5 ? 22.8 μg rang). Urine samples at 6 hour intervals clearly demonstrated a ten-fold diurnal variation, from 0.8 μg/6 hr during the day to 8.6 μg/6 hr at night.     

Role of mast cells in health: daily rhythmic variations in their number, exocytotic activity, histamine and serotonin content in the rat thyroid gland.

A chronobiologic transverse study on rat thyroid has been carried out to investigate whether mast cells and their content in biogenic amines normally undergo daily variations and whether these are related to circadian activity of the gland. The mean number of mast cells per microscopic field presents daily variations ranging from 10.9 +/- 3 to 14.6 +/- 3.8 in males and from 8.4 +/- 1.9 to 14.8 +/- 3 in females: these variations show a circadian trend in both sexes, with a 12 hrs period and two peaks at about 11:10/23:10. The mean percentage of degranulated mast cells per microscopic fields shows daily variations ranging from 51 +/- 11 to 60.4 +/- 14.2 in males and from 49.8 +/- 12.5 to 58.3 +/- 13.6 in females; these variations present a circadian rhythm with a 24 hrs period and a mean peak at 02:00. The histamine content of the gland varies in 24 hrs from 20.93 +/- 1.19 micrograms/g w w to 38.08 +/- 1.7 micrograms/g w w, without any sex-related difference: these variations show a rhythmic trend with a 12 hrs period and two peaks at 09:10/21:10. Serotonin content of thyroid presents circadian variations from 15.98 +/- 0.83 to 23.23 +/- 0.61 micrograms/g w w, with a 12 hrs period and two peaks at 04:20/16:20. Whereas the variations of mast cell exocytosis and of serotonin content seem to be chronobiologically linked to circadian variations of gland activity, evaluated on the basis of free and total tetraiodothyronine serum levels, the variations of mast cell number appear to be related to those of thyroid and blood histamine. The present data support the hypothesis that mast cell activity should not be considered as only linked to inflammation or allergic responses.     

Radioimmunoassay of urinary testosterone glucuronoside

A simple method is described for the determination of testosterone glucuronoside in urine without prior hydrolysis or extraction. Appropriate amounts (5 μl male, 50 μ1 female urine) are dried at 100 °C to eliminate nonspecific binding by urinary proteins. The residues are cooled, redissolved in buffer and equilibrated with antiserum to testosterone-17β-glucosiduronate-bovine serum albumin and tritiated testosterone glucuronoside. The unbound steroid is removed with dextran-coated charcoal. The total random theoretical percentage error was calculated as 7 %. The inter and intra assay precision were 18 and 9 % respectively. Daily urine collections from 8 complete menstrual cycles have been analysed and the results related to the peak of urinary LH. In seven subjects, there was a visible peak of testosterone glucuronoside at mid cycle (LH peak ± 1 day), in six a distinct peak in the luteal phase, and in five a smaller peak during the follicular phase. The levels of testosterone glucuronoside in groups of healthy men and women were 273 ± 169 and 19 ± 10 μg/24 hrs. The corresponding range of values by a gas-liquid chromatographic method were 204 ± 102 and 14 ± 8. The values are discussed.     

Circadian variations in plasma LH and FSH in juvenile and adult male mice

Experiments were performed to ascertain circadian fluctuations in plasma levels of LH and FSH in juvenile and adult male mice. Animals under natural lighting (11 h day/13 h night) were killed at 1-hour intervals over a 24-hour period. There were large variations in plasma LH concentrations between animals sacrificed within each killing period. Baseline LH levels (values lower than 60 ng/ml) showed a significant 24-hour periodicity in adult males. FSH concentrations exhibited significant diurnal variations in juvenile and adult males. There was significant influence of age on the temporal pattern and 24-hour mean plasma hormone levels.     

Technical Note: Bioluminescence Measurements of the Antilisterial Activity of Nisin: Comparison with Ampicillin and Streptomycin

The influence of nisin on intracellular ATP and cell numbers of Listeria monocytogenes strain Scott A was determined and compared with the effect of ampicillin and streptomycin under similar conditions. In the presence of nisin (3–12 μg/ml), intracellular ATP and cell numbers decreased rapidly during the first hour at 35°C and extracellular ATP increased. Cell numbers and intracellular ATP increased after 3 h of incubation. No effect was observed in cells treated with ampicillin (3–12 μg/ml) and streptomycin (15–60 μg/ml) during the first hour. However, concentrations of ≥3 μg/ml ampicillin and ≥30 μg/ml streptomycin were listeriostatic after 3 h of incubation. Progressive loss of viability and reduction of intracellular ATP were observed in resting cells in PBS (pH 7.2) containing increasing concentrations of the antimicrobials. Rapid accumulation of extracellular ATP, observed immediately after treatment with nisin but not with the antibiotics, supports the reported collapse of proton motive force in L. monocytogenes by nisin.     

Diurnal Profiles of Blood Glucose in Relation to Time of Administration of Melatonin in Male Spotted Munia (Lonchura punctulata)

The study was aimed at demonstration of the effect of a single acute dose of melatonin (0.5 mg/ 100 g body wt.) on the diurnal profile of blood glucose in male spotted munia in relation to the administration of hormone at the onset of light (i.e., at 06.00 h) or at the onset of darkness (i.e., at 18.00 h) under natural photoperiodic (~12L : 12D) conditions. Blood samples from all birds belonging to the control, sham-control (administered only with the vehicle of hormone, i.e., ethanol-saline 1:9 v/v), and melatonin treated groups were collected at four time points, i.e. 06.00 h, 12.00 h, 18.00 h, and 24.00 h, in a 24 hour cycle. The blood glucose levels in control and sham-control birds showed marked variation with regard to the time of sampling, with a mid-day peak and morning nadir. Exogenous melatonin induced a significant alteration in this diurnal pattern of blood glucose with a marked variation in relation to the time of administration of melatonin. While morning administration of melatonin resulted in hypoglycemia at 12.00 h and 24.00 h and hyperglycemia at 18.00 h, the response to evening injection of melatonin was only hypoglycemic at 24.00 h leaving the glycemic values at other time-points almost unaltered compared to the blood glucose levels in control and sham-control munias. The results of this investigation demonstrate for the first time that a schedule of morning administration of melatonin induces a more broad range of variations in the blood glucose levels than a schedule of evening administration does.     

Diurnal Profiles of Blood Glucose in Relation to Time of Administration of Melatonin in Male Spotted Munia (Lonchura punctulata)

The study was aimed at demonstration of the effect of a single acute dose of melatonin (0.5 mg/ 100 g body wt.) on the diurnal profile of blood glucose in male spotted munia in relation to the administration of hormone at the onset of light (i.e., at 06.00 h) or at the onset of darkness (i.e., at 18.00 h) under natural photoperiodic (~12L : 12D) conditions. Blood samples from all birds belonging to the control, sham-control (administered only with the vehicle of hormone, i.e., ethanol-saline 1:9 v/v), and melatonin treated groups were collected at four time points, i.e. 06.00 h, 12.00 h, 18.00 h, and 24.00 h, in a 24 hour cycle. The blood glucose levels in control and sham-control birds showed marked variation with regard to the time of sampling, with a mid-day peak and morning nadir. Exogenous melatonin induced a significant alteration in this diurnal pattern of blood glucose with a marked variation in relation to the time of administration of melatonin. While morning administration of melatonin resulted in hypoglycemia at 12.00 h and 24.00 h and hyperglycemia at 18.00 h, the response to evening injection of melatonin was only hypoglycemic at 24.00 h leaving the glycemic values at other time-points almost unaltered compared to the blood glucose levels in control and sham-control munias. The results of this investigation demonstrate for the first time that a schedule of morning administration of melatonin induces a more broad range of variations in the blood glucose levels than a schedule of evening administration does.     

Seasonally Dependent Effect of Ectopic Pituitary Grafts on 24-Hour Rhythms in Serum Prolactin and Gonadotropins in Rats

To assess to what extent the presence of an ectopic pituitary differentially affected circulating prolactin (PRL) and gonadotropin levels at different times of the year, rats kept under 12h light, 12h dark (12:12 LD) photoperi-ods and receiving a pituitary graft or a sham operation in summer or winter were examined 3 months later. In both male and female sham-operated rats, a circadian variation in serum PRL levels was found, with an acrophase varying from 21:53h to 00:54h and the mesor and amplitude higher in spring than autumn in males and higher in autumn than in spring in females. After grafting a pituitary, changes in serum PRL related to time of day were no longer observed. In pituitary-grafted male rats killed during spring, serum PRL levels were higher than controls at only a few time points throughout the 24h cycle, whereas in rats killed during autumn, there were no significant differences in PRL levels between grafted and control rats. Pituitary-grafted female rats killed during spring showed serum PRL levels significantly higher than those of sham-operated rats, while in female rats killed in autumn, PRL levels of pituitary-grafted and sham-operated rats did not differ. Significant variations of luteinizing hormone (LH) related to time of day were found in sham-operated male rats only, with acrophases at 23:52h and 00:24h for spring and autumn, respectively, and the mesor and amplitude of the rhythm significantly higher in autumn. Pituitary transplants suppressed 24h variations in circulating LH and depressed its levels during the two seasons examined. As far as follicle-stimulating hormone (FSH), pituitary grafts decreased circulating levels, with the extent of decrease higher during autumn than in spring. The results indicate that some endocrine consequences of the grafting of an ectopic pituitary are dependent on time of year.     

Methodological Issues in Studies of Rhythms in Human Performance

In this review various sources of measurement error are considered in the context of investigating rhythms in human performance. The reproducibility of performance in any exercise task is an important factor if rhythmic variations are to be detectable. Available physical performance tests range from simple efforts lasting only a couple of seconds to sustained endurance exercise. When measuring muscle strength, the options include static or dynamic actions, slow or fast movements, voluntary or electrically stimulated contractions and maximal force or maximal power output. For studies of circadian rhythms the researcher has to choose between using nychthemeral or controlled conditions, and the number of times a day to be used for observations, and to decide how to control for loss of sleep, diet and prior activity. The need to recover energy between tests has led research groups to employ diurnal rhythm models in preference to cosinor analysis of circadian designs. The use of male subjects has also been favoured due to difficulties of controlling for menstrual cycle phase. Nevertheless recent attention has been given to research models for investigating the effects of rhythmic variations in female steroid hormones and on interactions between circadian and circamensal rhythms. There are real challenges in exploring seasonal variations in human performance and in examining how the body adjusts after desynchronisation as occurs during nocturnal shift-work and travelling across multiple time zones. The methods adopted must accommodate flexibility between laboratory-based and field-studies depending on the context of the research questions being pursued.     

Methodological Issues in Studies of Rhythms in Human Performance

In this review various sources of measurement error are considered in the context of investigating rhythms in human performance. The reproducibility of performance in any exercise task is an important factor if rhythmic variations are to be detectable. Available physical performance tests range from simple efforts lasting only a couple of seconds to sustained endurance exercise. When measuring muscle strength, the options include static or dynamic actions, slow or fast movements, voluntary or electrically stimulated contractions and maximal force or maximal power output. For studies of circadian rhythms the researcher has to choose between using nychthemeral or controlled conditions, and the number of times a day to be used for observations, and to decide how to control for loss of sleep, diet and prior activity. The need to recover energy between tests has led research groups to employ diurnal rhythm models in preference to cosinor analysis of circadian designs. The use of male subjects has also been favoured due to difficulties of controlling for menstrual cycle phase. Nevertheless recent attention has been given to research models for investigating the effects of rhythmic variations in female steroid hormones and on interactions between circadian and circamensal rhythms. There are real challenges in exploring seasonal variations in human performance and in examining how the body adjusts after desynchronisation as occurs during nocturnal shift-work and travelling across multiple time zones. The methods adopted must accommodate flexibility between laboratory-based and field-studies depending on the context of the research questions being pursued.