Episodic nyctohemeral secretion of melatonin in adult humans: Lack of relation with LH pulsatile pattern

1990 ◽  
Vol 122 (1) ◽  
pp. 76-82 ◽  
Author(s):  
Alberto de Leiva ◽  
Federico Tortosa ◽  
Miguel A. Peinado ◽  
José Serrano ◽  
José Rodriguez-Espinosa ◽  
...  
Keyword(s):  
Mean Amplitude ◽  
Melatonin Secretion ◽  
Melatonin Concentration ◽  
Significant Difference ◽  
Adult Humans ◽  
Early Follicular Phase ◽  
The Mean ◽  
Normal Women ◽  
Normal Men ◽  
Lh Secretion

Abstract The concentration of melatonin and LH were determined in plasma samples obtained at 10-min intervals during 4 h of darkness (00.00-04.00 h) from 4 normal women, age 23-27 years, in the early follicular phase of the menstrual cycle and in 6 normal men, age 23-31 years. Additionally, melatonin concentration was determined in samples obtained from the men at 10-min intervals for 4 h during the day (10.00-14.00 h). A pulsatile pattern of melatonin secretion was found for all the subjects during darkness. There was no significant difference between women and men as to the number of pulses (2.8 ± 0.5 vs 5.2 ± 1.0 per 4 h), amplitude of pulses (51.3 ± 28 vs 27.2 ± 6 ng/l), concentration per 4 h (32.5 ± 13 vs 31.0 ± 5 ng/l), or apparent half-life of melatonin (19.3 ± 2.3 vs 15.3 ± 7.5 min). The mean amplitude of the melatonin pulse correlated (r = 0.863, p<0.001) with the mean melatonin concentration per 4 h. A pulsatile LH secretion pattern was found for the 10 subjects and did not correlate significantly with the melatonin secretion pattern. The results are consistent with an independent signal for the demonstrated nyctohemeral pulsatile melatonin and LH secretions.

Serum ionic fluoride: normal range and relationship to age and sex.

1976 ◽  
Vol 22 (11) ◽  
pp. 1884-1888 ◽  
Author(s):  
H Husdan ◽  
R Vogl ◽  
D Oreopoulos ◽  
C Gryfe ◽  
A Rapoport
Keyword(s):  
Significant Variation ◽  
Electrode System ◽  
Confidence Limits ◽  
Normal Range ◽  
Ionic Fluoride ◽  
Significant Difference ◽  
The Mean ◽  
Normal Women ◽  
Fluoride Electrode ◽  
Normal Men

Abstract We used the Orion fluoride electrode system to determine the normal range of serum ionic fluoride concentrations and to investigate its relationship to sex and age (A). 87 normal men, aged 18-92 years (mean, 46 years), and 49 normal women, age 19-64 years (mean, 38 years), participated in the study. At the 95% confidence limits, males less than 45 years old had a normal range of 0.29 to 1.52 mumol/litre and males greater than or equal to 45 years old 0.29 + 0.0101 (A-45) to 1.52 + 0.0101 (A-45) mumol/litre. Females, however, had a normal range of 0.022A - 0.32 to 0.022A + 1.07 mumol/litre. A group of 51 men 18-44 years old was compared with a group of 36 men 46-92 years old. The mean serum F- of the older group was shown to be significantly greater (P less than 0.01) than that of the younger group. Factors related to serum ionic fluoride values are (a) tea as an important source of dietary F-, (b) the lack of significant variation during daytime hours, and (c) the lack of significant difference in concentration between serum and plsma F-.

Influence of eye colors of Caucasians and Asians on suppression of melatonin secretion by light

2007 ◽  
Vol 292 (6) ◽  
pp. R2352-R2356 ◽  
Author(s):  
Shigekazu Higuchi ◽  
Yutaka Motohashi ◽  
Keita Ishibashi ◽  
Takafumi Maeda
Keyword(s):  
Pupil Size ◽  
Light Exposure ◽  
Melatonin Secretion ◽  
Melatonin Concentration ◽  
Human Eye ◽  
Starting Time ◽  
Significant Difference ◽  
Eye Pigmentation ◽  
Salivary Melatonin ◽  
The Mean

This experiment tested effects of human eye pigmentation depending on the ethnicity on suppression of nocturnal melatonin secretion by light. Ten healthy Caucasian males with blue, green, or light brown irises (light-eyed Caucasians) and 11 Asian males with dark brown irises (dark-eyed Asians) volunteered to participate in the study. The mean ages of the light-eyed Caucasians and dark-eyed Asians were 26.4 ± 3.2 and 25.3 ± 5.7 years, respectively. The subjects were exposed to light (1,000 lux) for 2 h at night. The starting time of exposure was set to 2 h before the time of peak salivary melatonin concentration of each subject, which was determined in a preliminary experiment. Salivary melatonin concentration and pupil size were measured before exposure to light and during exposure to light. The percentage of suppression of melatonin secretion by light was calculated. The percentage of suppression of melatonin secretion 2 h after the start of light exposure was significantly larger in light-eyed Caucasians (88.9 ± 4.2%) than in dark-eyed Asians (73.4 ± 20.0%) ( P < 0.01). No significant difference was found between pupil sizes in light-eyed Caucasians and dark-eyed Asians. These results suggest that sensitivity of melatonin to light suppression is influenced by eye pigmentation and/or ethnicity.

LH in polycystic ovary syndrome: reproducibility and pulsatile secretion

1989 ◽  
Vol 121 (1) ◽  
pp. 185-191 ◽  
Author(s):  
A. P. Murdoch ◽  
P. J. Diggle ◽  
M. C. White ◽  
P. Kendall-Taylor ◽  
W. Dunlop
Keyword(s):  
Polycystic Ovary Syndrome ◽  
Polycystic Ovary ◽  
Ovary Syndrome ◽  
Blood Samples ◽  
Significant Difference ◽  
Early Follicular Phase ◽  
Within Subjects ◽  
Complicated Pattern ◽  
Normal Women ◽  
Lh Secretion

ABSTRACT Serum concentrations of LH are increased in polycystic ovary syndrome (PCOS). We have investigated two aspects of LH secretion which have not previously been reported: its reproducibility within individuals and the pattern of superimposed pulses of LH secretion. In nine patients with PCOS the mean concentration of LH was calculated from 24 blood samples taken at 15-min intervals for 6 h on two or three occasions over 1 year. Results showed differences in mean LH between subjects but reproducible concentrations within subjects over that period. It has been shown that LH is secreted in a complicated pattern of superimposed pulses which can be characterized by using the statistical methods of time-series analysis. To evaluate these pulse patterns of LH we studied nine patients with PCOS and compared the results with those of 12 normal women in the early follicular phase of the ovarian cycle. Blood samples were taken at either 5-min intervals for 6 h or 1-min intervals for 1 h. Pulses were detected in both groups at frequencies of about 1 h and 2 to 3 min. There was no significant difference in the pulse frequencies between the patients and controls but the amplitude of both groups of pulses was increased in the PCOS patients. Journal of Endocrinology (1989) 121, 185–191

Colorimetric Method for Rapid Determination of Serum Arginase

1967 ◽  
Vol 13 (10) ◽  
pp. 900-908 ◽  
Author(s):  
Brigitta Mellerup
Keyword(s):  
Rapid Determination ◽  
Colorimetric Method ◽  
Normal Range ◽  
Clinical Routine ◽  
Mean Values ◽  
Enzymatic Formation ◽  
Significant Difference ◽  
The Mean ◽  
Normal Men

Abstract A method for the determination of serum arginase is given which combines the enzymatic formation of urea with the sensitive method of Coulombe (1) for measuring this substance. This procedure allows more accurate determinations in the normal range than do previous methods described and is convenient for clinical routine. Significant difference is found between the mean values of normal men and women, 3.9 units/L. for the former and 2.9 units/L. for the latter.

VESTIBULAR AFFERENTS POPULATION ACTIVATED BY VARIOUS MODES FOR ELICITING OCULAR AND CERVICAL VESTIBULAR-EVOKED MYOGENIC POTENTIALS

2011 ◽  
Vol 23 (06) ◽  
pp. 527-532 ◽  
Author(s):  
Shou-Jen Wang ◽  
Fu-Shan Jaw ◽  
Yi-Ho Young
Keyword(s):  
Healthy Subjects ◽  
Mean Amplitude ◽  
Vestibular Evoked Myogenic Potentials ◽  
Force Level ◽  
Characteristic Parameters ◽  
Stimulation Mode ◽  
Vestibular Afferents ◽  
Significant Difference ◽  
The Mean

This study compared cervical and ocular vestibular-evoked myogenic potentials (cVEMPs and oVEMPs) between air-conducted sound (ACS) and bone-conducted vibration (BCV) modes to determine whether these two stimulation modes activate the same population of primary vestibular afferents. Fifteen healthy subjects underwent cVEMP and oVEMP tests using ACS stimuli at 127 dB pe SPL and BCV stimuli at 128 dB force level. The characteristic parameters of cVEMPs and oVEMPs were compared between ACS and BCV modes. The mean p13 and n23 latencies of ACS-cVEMPs were significantly longer than those of BCV-cVEMPs. Likewise, the mean nI and pI latencies for ACS-oVEMPs were also significantly longer than those for BCV-oVEMPs. There was no significant difference in the mean amplitude of cVEMPs between the ACS and BCV modes. However, comparing the oVEMP amplitude, a relationship: (Amplitude of BCV-oVEMP) = 2.3 x (Amplitude of ACS-oVEMP) was demonstrated. In conclusion, the population of primary vestibular afferents activated by ACS and BCV stimuli is similar for cVEMPs. In contrast with oVEMPs, BCV mode activates more number of primary vestibular afferents than ACS mode does. In interpreting oVEMP and cVEMP results, stimulation mode should be checked first.

Alterations of the hypothalamic GnRH interpulse interval sequence over the normal menstrual cycle

1988 ◽  
Vol 255 (5) ◽  
pp. E696-E701 ◽  
Author(s):  
N. Santoro ◽  
J. P. Butler ◽  
M. Filicori ◽  
W. F. Crowley
Keyword(s):  
Menstrual Cycle ◽  
Renewal Process ◽  
Gnrh Secretion ◽  
Late Luteal Phase ◽  
Normal Menstrual Cycle ◽  
Lh Release ◽  
Interval Sequence ◽  
Normal Women ◽  
Normal Men ◽  
Lh Secretion

Luteinizing hormone (LH) is released in a pulsatile fashion from the anterior pituitary in response to hypothalamic gonadotropin-releasing hormone (GnRH) secretion. Previous autocorrelation analysis of the sequence of interpulse intervals of LH secretion in normal men has supported the hypothesis that the underlying hypothalamic mechanism of GnRH secretion governing episodic LH release is a renewal process, indicating that hypothalamic "memory," if present, does not extend back further in time than the preceding secretory pulse. A similar analysis of pulsatile LH secretion was undertaken in 45 studies of normal women, obtained throughout the menstrual cycle. Analysis of these studies revealed a process consistent with renewal throughout the follicular and early luteal phases. However, this relationship appears to break down in the mid-to-late luteal phase, indicating that alternative feedback pathways provide an overriding influence on the underlying renewal process of hypothalamic GnRH secretion. Pulsatile progesterone secretion by the corpus luteum, which first emerges at this stage of the menstrual cycle, may be the agent responsible for this feedback.

The pulsatile secretion of bioactive luteinising hormone in normal adult men

1990 ◽  
Vol 122 (5) ◽  
pp. 643-650 ◽  
Author(s):  
J. Alan Talbor ◽  
R. Stuart ◽  
C. Rodger ◽  
Steven M. Shalet ◽  
Malcolm D. Littley ◽  
...  
Keyword(s):  
Temporal Relationship ◽  
Mean Amplitude ◽  
Adult Men ◽  
Lh Pulsatility ◽  
The Mean ◽  
Normal Men ◽  
Relationship Of ◽  
Low Amplitude ◽  
Mouse Leydig Cell

Abstract. We have studied bioactive and immunoreactive LH pulsatility in 11 normal men. The temporal relationship of plasma LH, testosterone, and FSH were also investigated. Blood samples were taken at 10-minute intervals for 6 h and bioactive LH levels were determined using an in vitro mouse Leydig cell bioassay. Testosterone, LH and FSH were determined by standard radioimmunoassay. Twenty-two bioactive LH pulses were detected (amplitude 8.5±4.9 IU/l, mean±sd) with a frequency of 2±0.8/6 h compared with only 18 immunoreactive LH pulses (amplitude of 3.6±1.8 IU/l) and a frequency of 1.6±0.5/6 h. Bioactive:immunoreactive LH ratios increased (p<0.01) from the preceding pulse nadirs (2.26, range 1.66-4.28) to the pulse peaks (2.71, range 1.99-4.67). Twenty FSH pulses (seen in all but one subject) of low amplitude (0.7±0.6, median 0.5 IU/l) were also present. There was a close temporal relationship between testosterone and FSH secretion with bioactive and immunoreactive LH pulses with lags of 30-60 and 0 min, respectively. We conclude that immunoreactive LH pulses are discordant from bioactive LH pulses in 18% of occasions. Further, the mean amplitude of bioactive episodes were approximately 2.6 times greater than that of immunoreactive episodes, whereas interpulse period and pulse duration were similar. The increase in bioactive:immunoeactive ratio at pulse peaks may indicate that in normal men LH pulses are enriched with a more biopotent form of the molecule.

scholarly journals The Relationship Between Seasonality, Latitude and Tuberculosis Notifications in Pakistan

2020 ◽  
Author(s):  
Mohsin F. Butt ◽  
Sidra Younis ◽  
Zhenqiang Wu ◽  
Syed H. Hadi ◽  
Abdullah Latif ◽  
...  
Keyword(s):  
Seasonal Variation ◽  
Mean Amplitude ◽  
The United States ◽  
Control Programme ◽  
Seasonal Adjustment ◽  
United States Census ◽  
United States Census Bureau ◽  
Pulmonary Tb ◽  
Significant Difference ◽  
The Mean

Abstract BackgroundPakistan is amongst the top 20 highest burden tuberculosis (TB) countries in the world. Approximately 369,548 cases of TB (all forms) were notified in 2018, with an estimated incidence of 265 per 100,000 people per year. In other settings, TB has been shown to demonstrate seasonal variation, with higher incidence in the spring/summer months and lower incidence in the autumn/winter; the amplitude of seasonal variation has also been reported to be higher with increasing distance from the equator.MethodsNotifications of newly-diagnosed pulmonary and extrapulmonary TB cases were obtained for 139 districts in Pakistan from 2011–2017. Data were provided by the Pakistan National TB Control Programme, Islamabad, Pakistan. Statistical analyses were performed to determine whether there was seasonal variation in TB notifications in Pakistan; whether the amplitude of seasonal variation in TB notifications varied according to latitude; whether the amplitude of seasonal variation of TB in Pakistan differed between extrapulmonary TB vs. pulmonary TB. To assess the quarterly seasonality of TB, we used the X-13-ARIMA-SEATS seasonal adjustment programme from the United States Census Bureau. The mean difference and corresponding 95% confidence intervals of seasonal amplitudes between different latitudes and type of TB were estimated using linear regression.ResultsTB notifications were highest in quarter 2, and lowest in quarter 4. The mean amplitude of seasonal variation was 25.5% (95% CI 25.0–25.9%). The mean seasonal amplitude of TB notifications from latitude 24.5ºN-<26.5ºN was 29.5% (95% CI 29.3–29.7%) whilst the mean seasonal amplitude of TB notifications from latitude 34.5ºN -<36.5ºN was 21.7% (95% CI 19.6–23.9%). The mean seasonal amplitude of TB notifications across Pakistan between latitudes 24.5ºN to 36.5ºN reached statistically significant difference (p < 0.001). The amplitude of seasonal variation was greater for extrapulmonary TB (mean seasonal amplitude: 21.6%, 95% CI 32.1–33.1%) vs. smear positive pulmonary TB (mean seasonal amplitude 32.6%, 95% CI 21.4–21.8%), p < 0.001.ConclusionTB notifications in Pakistan exhibit seasonal variation with a peak in quarter 2 (April-June) and trough in quarter 4 (October-December). The amplitude of seasonality decreases with increasing latitude, and is more pronounced for extrapulmonary TB than for pulmonary TB.

Radioimmunoassay of testosterone not bound to sex-steroid-binding protein in plasma.

1989 ◽  
Vol 35 (8) ◽  
pp. 1609-1614 ◽  
Author(s):  
H Déchaud ◽  
H Lejeune ◽  
M Garoscio-Cholet ◽  
R Mallein ◽  
M Pugeat
Keyword(s):  
Binding Capacity ◽  
Binding Protein ◽  
Mass Action ◽  
Sex Steroid ◽  
Human Pathology ◽  
The Mean ◽  
Steroid Binding ◽  
Normal Women ◽  
Normal Men ◽  
Steroid Binding Protein

Abstract To measure the concentration of testosterone (T) that is not bound to sex-steroid-binding protein (SBP) in plasma, we quantified by radioimmunoassay the T in the supernates of plasma samples after precipitation with 50%-saturated ammonium sulfate. The concentrations of non-SBP-bound T. directly measured with this assay, correlated significantly (P less than 0.001) with those deduced from measurement of the percentage of non-SBP-bound T determined with [3H]T as tracer or from mathematical models according to the law of mass action. It also correlated significantly with the ratio of T to SBP and with the concentration of nonbound T. As determined with this assay, the mean concentration of non-SBP-bound T in normal men was higher in young (4.67, SD 2.68 nmol/L; n = 30) than in older (greater than 40 years) subjects (2.48, SD 1.61 nmol/L; n = 35; P less than 0.001) and lower than normal in hyperthyroid (1.61, SD 0.91 nmol/L; P less than 0.01) or infertile men (3.28, SD 1.70 nmol/L; P less than 0.01). In women, non-SBP-bound T was higher in hirsute patients (0.24, SD 0.11 nmol/L; P less than 0.01) and was lower during pregnancy (0.09, SD 0.05 nmol/L; P less than 0.05) than in normal women during the follicular phase (0.16, SD 0.07 nmol/L). We conclude that this direct measurement of non-SBP-bound T in plasma is suitable for routine use and represents a reliable index of androgenicity in human pathology, particularly when alterations of the binding capacity of SBP modify the concentrations of total T.

EFFECT OF GLUCOCORTICOIDS ON PLASMA TESTOSTERONE IN MEN

1978 ◽  
Vol 89 (1) ◽  
pp. 126-131 ◽  
Author(s):  
G. Schaison ◽  
F. Durand ◽  
I. Mowszowicz
Keyword(s):  
Chorionic Gonadotrophin ◽  
Human Chorionic Gonadotrophin ◽  
Plasma Testosterone ◽  
Acth Stimulation ◽  
Testosterone Levels ◽  
Before And After ◽  
The Mean ◽  
Normal Men ◽  
Lh Secretion ◽  
Dexamethasone Suppression

ABSTRACT ACTH decreases plasma testosterone levels in men. The aim of this study was to assess the part played by the glucocorticoids in this effect, and the mechanism of their action. Plasma androstenedione, testosterone, cortisol and LH were measured in 8 normal men, before and after the following tests: ACTH stimulation (2 mg im), metyrapone administration (500 mg/every 4 h/6 times) and dexamethasone suppression (8 mg/day/3 days). In addition, androstenedione and testosterone were evaluated under human chorionic gonadotrophin (5000 IU HCG/day/3 days) before and after dexamethasone suppression (8 mg/day/6 days). In all patients, ACTH decreased plasma testosterone from 5.87 ± 1.59 (sd) ng/ml to 3.06 ± 0.8 (sd) ng/ml (P < 0.001). In contrast, after metyrapone, the mean plasma testosterone was increased to 6.98 ± 1.75 (sd) ng/ml. This increase, though not statistically significant, was observed in all patients but one. Both tests resulted in a significant increase of plasma androstenedione (P < 0.01 and P < 0.001, respectively). Dexamethasone suppressed both testosterone and androstenedione levels. None of the three tests had a significant effect on the LH concentration. HCG injection increased the mean plasma testosterone to 11.46 ± 2.80 ng/ml. Dexamethasone significantly depressed (P < 0.01) the testosterone response to HCG. These data are consistent with the following conclusions: 1) The decrease of plasma testosterone levels, observed in men after ACTH administration, is not observed after metyrapone induced ACTH increase. This confirms that it is related to cortisol levels rather than to ACTH itself. 2) Glucocorticoids act directly on testicular biosynthesis since they do not induce any change in LH secretion and since dexamethasone reduces testosterone response to HCG.

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