Showing papers by "Ghent University published in 1976"
TL;DR: It is concluded that the adrenal cortex is almost the exclusive source of plasma estradiol, estrone, progesterone, and 17OH progester one and the most important source of Plasma dehydroepiandrosterone and that hCG stimulation with 5000 IU daily for 3 days, hardly influences steroid secretion by postmenopausal ovaries.
Abstract: The origin of plasma sex hormones in postmenopausal women was studied by determining plasma levels under basal conditions, after ACTH stimulation, and after dexamethasone suppression, as well as after hCG stimulation. Values obtained in postmenopausal women were compared with values observed during the follicular phase of the cycle in young women on the one hand, and with values in ovariectomized women of postmenopausal age on the other hand. All sex steroid levels studied with the exception of estrone, were significantly lower in postmenopausal women than in young women during the early follicular phase of the cycle. In ovariectomized women only androgen levels (testosterone, androstenedione, dihydrotestosterone, and to a lesser extent dehydroepiandrosterone,) were lower than in normal postmenopausal women, estrogen, 17 hydroxyprogesterone, and progesterone levels being similar. ACTH increased all plasma steroid levels except estradiol, whereas after dexamethasone, all sex hormone levels were significantly decreased. hCG stimulation finally caused an increase of borderline statistical significance in testosterone, dehydroepiandrosterone, and 17-hydroxyprogesterone levels. We have concluded from this study that the adrenal cortex is almost the exclusive source of plasma estradiol, estrone, progesterone, and 17OH progesterone and the most important source of plasma dehydroepiandrosterone; that the postmenopausal ovary appears to be responsible for about 50% of plasma testosterone and 30% of androstenedione levels; and that hCG stimulation with 5000 IU daily for 3 days, hardly influences steroid secretion by postmenopausal ovaries.
367 citations
TL;DR: Conditions are derived for which there exists a state feedback control such that the closed loop system is stable in the mean square sense and to cases in which the noise intensities are arbitrarily large.
209 citations
TL;DR: Large quantities of Met5-enkephalin are synthesised and its preferential conformation in solution is determined using high field proton magnetic resonance spectroscopy at variable temperatures, coupling constants in relation with Karplus–Bystrov curves2 and conformational energy steric maps3.
Abstract: THE discovery by Hughes et al.1 that peptides (the enkephalins) could be the endogenous agonists of opiates in brain represents a challenge to medical chemistry both in its fundamental aspects and for the possible development of new therapeutic approaches. To understand how non-peptidic substances belonging to various chemical classes can mimic the action of the pentapeptide enkephalins it is first necessary to determine the spatial arrangement of the latter. We have thus synthesised large quantities of Met5-enkephalin (H–Tyr–Gly–Gly–Phe–Met–OH) and determined its preferential conformation in solution using high field proton magnetic resonance (PMR) spectroscopy at variable temperatures, coupling constants in relation with Karplus–Bystrov curves2 and conformational energy steric maps3.
159 citations
TL;DR: The combination of layer resistivity and thickness in the so-called Dar Zarrouk parameters S and T may be of direct use in aquifer protection studies and for the evaluation of hydrologic properties of aquifers.
Abstract: The combination of layer resistivity and thickness in the so-called Dar Zarrouk parameters S and T may be of direct use in aquifer protection studies and for the evaluation of hydrologic properties of aquifers. The protective capacity of a clayey aquifer overburden is proportional to its longitudinal unit conductance S which, in terms of aquifer protection, gets a dimension of time (e.g. infiltration time). Aquifer storage in fissured reservoirs may be determined from differential conductance measurements (ΔS). Combination of the expression for ΔS with an empirical expression for electric conduction in fissured media yields a simple formula for water content per unit surface area. Both principles and possible developments are illustrated for a set of carboniferous limestone basins.
158 citations
01 Mar 1976
TL;DR: In this article, a rotating circular cylinder immersed in a plane wave of the E or H type is considered and its equations are written in these coordinates, together with relevant constitutive equations and boundary conditions.
Abstract: Field calculations in the presence of rotating bodies with symmetry of revolution can be performed in the (inertial) laboratory frame of reference. Specific results are presented for a rotating circular cylinder immersed in a plane wave of the E or H type. Particular emphasis is put on the low-frequency limit, but some numerical data are also given for a typical frequency in the "resonance" region. The analysis becomes more complicated in the absence of symmetry of revolution. It is then necessary to solve the problem in a rotating system of coordinates. Maxwell's equations are written in these coordinates, together with the relevant constitutive equations and boundary conditions. The general formalism is applied to a typical two-dimensional configuration, viz., a cylinder immersed in an incident E wave. Considerable simplification obtains if all material velocities are negligible with respect to c, a condition which is always met in practice. Even simpler results are obtained if the cross-sectional dimensions of the cylinder are small with respect to λ. Some numerical results are presented, at low frequencies, for a dielectric cylinder of rectangular cross section.
153 citations
TL;DR: It is concluded that in males T, DHT and 17-OHP have an almost exclusive testicular origin; Δ4 has a mixed testicular and adrenal origin, whereas DHEA has a predominant and P an exclusive adrenalorigin in males.
142 citations
01 Jan 1976
TL;DR: The aim of the present study was to investigate the influence of estrogen therapy on some psychological functions in post-menopausal women by dividing subjects into placebo and experimental groups.
Abstract: The aim of the present study was to investigate the influence of estrogen therapy on some psychological functions in post-menopausal women. Twenty-six subjects, all volunteers, were divided into placebo and experimental groups and examined before and after 3 months of estrogen or placebo treatment.
92 citations
TL;DR: A preferential conformation of the endogenous opiate-like pentapeptide Met-Enkephalin in DMSO-d6 solution was proposed from high field 1H NMR experiments at variable temperature and complete analysis of the coupling constants in relation with conformational energy steric maps.
89 citations
79 citations
TL;DR: T, DHT, delta 4, and delta 4 levels showed statistically significant cyclical variations, with highest values in the periovulatory period and lowest values in early follicular and late luteal phase, while DHEA levels showed random variations during the cycle.
67 citations
TL;DR: In this article, atmospheric aerosols have been sampled monthly during 19 months at the Jungfraujoch in Switzerland (3752 m above sea level) and the geometric mean concentration of total suspended particulates is 3.1 μgm−3.
TL;DR: Thirteen of 31 Belgian Landrace pigs developed malignant hyperthermia (MH) after breathing halothane after a short period of exercise 1 h before the administration of the triggering agent increased the incidence of the syndrome to 100% in eight similar pigs.
Abstract: Thirteen of 31 Belgian Landrace pigs developed malignant hyperthermia (MH) after breathing halothane. A short period of exercise 1 h before the administration of the triggering agent increased the incidence of the syndrome to 100% in eight similar pigs. Clinical symptoms were more marked and developed more rapidly in the exercised pigs. All the reacting pigs became typically acidotic, developed rigor and died. Serum Na+, K+, Ca2+, c.p.k., l.d.h. and protein concentrations were increased to a variable extent during the reaction and there was an increase in p.c.v. also. No hyper-glycaemia was detected in pigs which were rested before receiving halothane. Four of the eight exercised pigs became markedly hyperglycaemic and plasma noradrenaline increased to higher values. Phosphocreatine and ATP decreased to low values and lactate increased in the muscles of all pigs which reacted. At the time of death, muscle glycogen had decreased significantly in the rested, but not in the exercised, MH pigs.
TL;DR: It is concluded from this study that a 30-year old woman with a history of recurrent goiter presents evidence of partial resistance to thyroid hormones.
Abstract: A 30-year old woman with a history of recurrent goiter, who had undergone two partial thyroidectomies, is described. She presented with tachycardia, nervousness and a fine tremor of the fingers. Initially, she had normal serum thyroid hormone levels: thyroxine (T4 (D)) 11.6 μg/100 ml, triiodothyronine (T3) 138 ng/100 ml, normal levels of binding proteins and a very high serum thyrotropin (TSH), 98 μU/ml During follow-up T4 (D) increased to 17.2 μg/100 ml, T3 increased to 277 ng/100 ml, while TSH decreased to 11 μU/ml. There was an exaggerated response of TSH to a peak value of 550 μU/ml after intravenous administration of 200 μg thyrotropin-releasing hormone (TRH). Administration of 60 mg prednisolone daily resulted in a blunting of the response to TRH. Administration of 50 μg T3 daily for 1 month resulted in a fall in serum TSH from 98 to 50 μU/ml. Later, when the serum TSH level had fallen spontaneously to 20 μU/ml, administration of 100 μg T3 daily for two weeks resulted in a fall in serum TSH...
TL;DR: The gas-liquid chromatographic (GLC) separation of a group of naturally occurring phenolic compounds embracing benzaldehyde, benzoic acid, cinnamaldehyde, Cinnamic acid, coumarin, flavone and isoflavone and derivatives has been studied.
TL;DR: 2-5 months after prostatectomy, T and DHT levels were significantly higher than immediately preoperatively and the preoperative stress may have influenced the preprostatectomy values.
Abstract: Plasma androgens [testosterone (T), 17β-hydroxy-5α-androstan-3-one (DHT), androst-4- en-3,17 dione(A), and dehydroepiandrosterone (DHEA)] as well as 17 hydroxyprogesterone were measured in a group of patients (age 60–80 yrs.) with benign prostatic hyperplasia (BPH) just before prostatectomy and compared to values obtained in subjects of similar age without signs of BPH. The most important difference was observed in the mean DHT level which was significantly (P < 0.025) higher than in the control group; mean T and free testosterone levels in BPH patients were slightly higher (P<0.05) in the age group 70–80 yrs; whereas in age group 60–70 mean values were similar to those observed in normal controls. Mean A, DHEA and 17 OHP and E2 levels were not significantly different in BPH patients when compared to age matched controls. 2–5 months after prostatectomy, T and DHT levels were significantly higher than immediately preoperatively. The preoperative stress may have influenced the preprostatectomy values.
TL;DR: The results of this study support the concept of subdividing the species S aureus into biotypes or ecotypes.
TL;DR: In this paper, a series of secondary N-1-(2-chloroalkylidene)amines has been prepared by condensation of disubstituted acetaldehydes with primary amines followed by chlorination with N-chlorosuccinimide in carbontetrachloride.
TL;DR: In this article, the Mossbauerspectrum of BiFeO3 was shown to consist of two superimposed six-line spectra, and the main distinction between the two iron sites is made up by the different ΔEQ values, even having opposite signs.
TL;DR: In the Watersportbaan, a β-mesosaprobic lake, fluctuations of the die-off indexes were governed in major part by the seasonal variations in insolation and the concomitant changes in pH and in temperature, while in the Coupure, a heavily polluted β-polysap Robic biotope, the indexes correlated primarily with the insolationand the temperature.
TL;DR: In this paper, the possibilities of the silver sulfide membrane electrode for the determination of cyanide are described; determinations by multiple standard addition and titration have been studied, and interferences have been checked.
TL;DR: Values of the reproductive potential of two harpacticoid copepods differ considerably according to temperature, and thus to the time of the year; during the spring bloom more than half the sexual potential is realized.
Abstract: The reproductive potential of two harpacticoid copepods, Tachidius dis~pes and Paronychocamptus nanus, as measured by the intrinsic rate of natural increase, r m, has been studied. The influence of temperature on all factors used in the calculation of r m has been taken into account. Generation time, which has also been determined in a third species, Nitocra typica, is the single factor which is most affected by temperature and which has the most pronounced effect on r m. Values of the reproductive potential differ considerably according to temperature, and thus to the time of the year; during the spring bloom more than half the reproductive potential is realized.
TL;DR: In this paper, a set of values for vicinal gauche coupling constants are given, allowing configurational predications in pyranose chairs, and the same sets of values can also be used for pyrano chairs.
Abstract: Typical sets of values for vicinal gauche coupling constants are given, allowing configurational predications in pyranose chairs.
TL;DR: It is suggested that the dopamine beta-hydroxylase activity in cerebrospinal fluid may be derived fromnoradrenergic neurons within the brain and that the enzyme is released together with noradrenaline.
TL;DR: The spatial pattern of the ostracod Cyprideis torosa (Jones, 1850) is aggregated and can be described by the negative binomial distribution as mentioned in this paper, and a method to picture the aggregations is described.
Abstract: The spatial pattern of the ostracod Cyprideis torosa (Jones, 1850) is aggregated and can be described by the negative binomial distribution. The fit of the observed distribution to the negative binomial is less well for the total number of females because females that are not carrying eggs tend to be independently distributed from both females carrying eggs and males. The aggregations are roughly circular with a radius of about 13 cm and may be themselves aggregated. A method to picture the aggregations is described.
TL;DR: In this paper, the structure, cation distribution, and cation valencies of the CuxMn3−xO4 spinel system are investigated by means of some selected experiments on specimens of this spinel systems and some similar Cu and Mn containing spinels.
Abstract: The structure, cation distribution, and cation valencies of the CuxMn3−xO4 spinel system are investigated by means of some selected experiments on specimens of this spinel system and some similar Cu and Mn containing spinels. Dilatation measurements reveal two important cation migration processes, namely the cation exchange between the octahedral and tetrahedral sublattices and the clustering of octahedral Mn3+. Infrared absorption measurements confirm that Cu1.5Mn1.5O4 and some similar CuMn compounds have 1:3 octahedral superstructure, which proves that tetrahedral Cu+ in presence of octahedral Mn4+ is the most stable configuration. The magnetic data are consistent with the proposed cation valancies and from the anomalous behaviour of the susceptibility above 600 K, it is deduced that the ionic configuration in Cu and Mn containing spinels is mainly described by the equilibrium, Cutetr+ + Mn ⇄ Cu + Mn, which shifts to the right at higher temperatures.
Struktur, Kationenverteilung und Kationenvalenzen des Spinellsystems CuxMn3−xO4 werden mit ausgewahlten Experimenten an Proben dieses Spinellsystems und einigen ahnlichen, Cu- und Mn-enthaltenen Spinellen, untersucht. Dilatationsmessungen ergeben zwei wesentliche Kationenwanderungsprozesse: Kationenaustausch zwischen dem Oktaeder- und Tetraeder-Untergitter sowie Clusterbildung von oktaedrischem Mn3+. Infrarot-Absorptionsmessungen zeigen. das Cu1,5Mn1,5O4 und einige ahnliche CuMn-Verbindungen 1:3-Oktaeder-Uberstrukturen besitzen, was darauf hinweist, das tetraedrisches Cu+ bei Anwesenheit von oktaedrischem Mn4+ die stabilste Konfiguration ist. Die magnetischen Werte sind konsistent mit vorausgesagten Kationenvalenzen; aus dem anomalen Verhalten der Suszeptibilitat oberhalb 600 K wird geschlossen. das die Ionenkonfiguration in Cu-und Mn-haltigen Spinellen im wesentlichen durch das Gleichgewicht Cu + Mn ⇄ ⇄ Cu + Mn beschrieben wird, das sich bei hoheren Temperaturen nach rechts verschiebt.
TL;DR: It is concluded that nociceptive afferents in the oro-facial area, most probably belonging to the A-delta group, have oligosynaptic inhibitory reflex connections with jaw-closing motoneurons.
TL;DR: In this paper, the eigenmodes of an inhomogeneous, anisotropic optical waveguide with arbitrary cross-section are computed using the finite element technique, based on a variational principle for the modes of a dielectric waveguide.
Abstract: Using the finite-element technique, the eigenmodes propagating in an inhomogeneous, anisotropic optical waveguide with arbitrary cross-section are computed The method is based on a variational principle for the modes of an anisotropic dielectric waveguide It is shown that very accurate results are obtained, even for the guides formed by very small changes in the refractive index As an example, the propagation characteristics of a channel guide embedded in LiNbO3 are computed