Showing papers by "Utrecht University published in 1977"
TL;DR: CM-Cellulose column chromatography proved to be extremely useful in separating phospholipid mixtures obtained by phosphatidyltransferase reactions of phospholIPase D and is also suitable for fractionation of other lipid extracts.
561 citations
TL;DR: In this article, the Weinberg model was used to obtain an upper bound of about 800 GeV on mass differences within a multiplet and no limit on the average mass can be deduced.
530 citations
TL;DR: The affinity order of cholesterol for the neutral phospholipids which can be deduced is sphingomyelin greater than phosphatidylcholine greater thanosphatidylethanolamine.
364 citations
TL;DR: In this paper, a Lower Carboniferous formation south of Cork, Ireland, characterized by sand/mud alternations at varying scales, several lithotypes are identified on the basis of relative sand content and primary sedimentary structures.
Abstract: In a Lower Carboniferous formation south of Cork, Ireland, characterized by sand/mud alternations at varying scales, several lithotypes could be singled out on the basis of relative sand content and primary sedimentary structures. The lithotypes are arranged in several types of sequences: coarsening upwards, coarsening-fining upwards, random, and in rare instances: fining upwards.
With increased gross sandcontent the sand intercalations thicken and show a richer array of structures, reflecting a wider range of energy conditions. The majority of the structures is interpreted as wave generated. Current formed structures play an insignificant role. Tidal effects could not be ascertained. The alternation of low- and high-energy lithotypes, occurring in sandy as well as muddy parts of the sequences is explained as resulting from the interplay of storm and fair weather conditions. The effect of shoaling bathymetry is reflected in sequences by an increasing importance of high-energy lithotypes.
The environment of deposition can be visualized as a muddy shallow marine platform on which longshore directed sandy shoals were formed under the influence of wave action. Depending on the degree of wave agitation and the availability of sand the shoals reached different stages of maturity: incipient, submerged or emergent. The sequential type encountered in vertical sections depends on the location of the line of logging and varies laterally as sandlenses thicken, amalgamate or die out.
340 citations
TL;DR: In this paper, it was pointed out that the duration of a Brownian collision is long enough to allow redistribution of the double layer and of the conformation of adsorbed macromolecules, but too short for adaptation of the surface charge or of the adsorption of macromoles.
340 citations
TL;DR: Defects in the posterior alveolus and hard palate up to a diameter of 4 cm can sometimes be closed by covering them with the buccal fat pad and grafting the latter with a split thickness skin graft.
333 citations
TL;DR: It is described here experiments devised to show that the asymmetric distribution of membrane phospholipids in blood cells may serve a biological purpose, by contributing to maintain the delicate balance between regulating haemostasis and avoiding thrombosis.
Abstract: ALTHOUGH there is compelling evidence that membrane components are non-randomly distributed between the two surfaces, the physiological significance of membrane asymmetry has so far remained obscure. Since the exterior surface of blood cell membranes is presumably devoid of negatively charged phospholipids which have a regulatory role in blood clotting, a possible function of lipid asymmetry in the coagulation process can be anticipated. We describe here experiments devised to show that the asymmetric distribution of membrane phospholipids in blood cells may serve a biological purpose, by contributing to maintain the delicate balance between regulating haemostasis and avoiding thrombosis.
299 citations
TL;DR: For instance, the authors showed that peptides derived from the anterior pituitary (ACTH, growth hormone), the intermediate lobe (α-MSH), and the posterior lobe (vasopressin) of the pituitar cortex have been shown to modulate conditioned behavior.
264 citations
TL;DR: In this article, the functional form of the solitons in the continuous Heisenberg spin system is studied in one dimension. And the results for soliton-soliton scattering in the isotropic case are presented.
Abstract: Solitons in the continuous Heisenberg spin system are studied in one dimension. We present results for soliton-soliton scattering in the isotropic case. For the anisotropic results we derive the functional form of the solitons. In both cases we investigated the linearized stability equations and found no evidence of instability.
243 citations
TL;DR: Investigating the action of seven purified phospholipases on intact platelets (both from human and pig) has revealed that membraneospholipids are available to enzymatic breakdown only if the phospholIPase can produce degradation in monolayers spread at an initial surface pressure of at least 34 dynes/cm.
238 citations
TL;DR: A fast and efficient method for the separation of (phospho)lipids by high performance liquid chromatography using n-hexane, 2-propanol, water mixtures as the solvent system is described.
TL;DR: Neuropeptides related to ACTH, MSH and LPH are involved in acquisition and maintenance of conditioned behaviour and affect the behaviour by a temporary selective increase in the state of arousal in limbic midbrain structures, thereby increasing the motivational influence of environmental stimuli.
Abstract: Neuropeptides related to ACTH, MSH and LPH are involved in acquisition and maintenance of conditioned behaviour. These peptides affect the behaviour by a temporary selective increase in the state of arousal in limbic midbrain structures, thereby increasing the motivational influence of environmental stimuli. Steroids of adrenal origin affect conditioned behaviour in a way opposite to that of ACTH and related peptides. Such steroids alter the arousal level in limbic midbrain structures to enhance discrimination and consequently the elimination of non relevant behaviourla responses. Neuropeptides related to ACTH play a basic role in motivational, learning and memory processes, while the pituitary-adrenal system through the secretion of corticosteroids has a secondary modulationg function.
TL;DR: The view that vasopressin is participating in the regulation of a variety of physiological processes by modulating neurotransmission in specific brain nuclei is supported by the results.
01 Jan 1977
TL;DR: The pituitary—adrenal system plays an essential role in homeostatic functions and the brain as a target for these hormones has been paid little attention.
Abstract: The pituitary—adrenal system plays an essential role in homeostatic functions Numerous aspects of stress-induced pituitary—adrenal activation in relation to peripheral mechanisms of adaptation have been studied since Selye’s first observations on the general adaptation syndrome some 40 years ago (Selye, 1950) Little attention, however, has been paid to the brain as a target for these hormones Clinical observations frequently commented on psychological changes in addition to electrophysiological alterations in hyper- as well as hypocorticism (Cleghorn, 1957; Von Zerssen, 1976) Many a laboratory experiment during the last decade, however, disclosed the implication of a number of pituitary and hypothalamic hormonal peptides on various brain functions The importance of these entities was revealed by observations on behavioral disturbances following extirpation of the pituitary gland in rats (de Wied, 1969); in animals with hereditary diabetes insipidus, which lack the ability to synthesize vasopressin (de Wied et al, 1975a); or in rats in which the action of vasopressin in the brain is neutralized by intraventricular administration of specific vasopressin antiserum (van Wimersma Greidanus et al, 1975a)
TL;DR: In this paper, the masses and number of neutral weakly interacting particles are derived using cosmological arguments, and it is shown that no such particles with a mass between 120 eV and 3 GeV can exist within the usual big band model.
TL;DR: From data obtained by differential scanning calorimetry phase diagrams, phase diagrams were constructed, using a thermodynamically based fitting method, to study binary mixtures of phosphatidylcholines in water.
TL;DR: The investigation by high-resolution ‘H nuclear magnetic resonance spectroscopy of the structure of the asialoglycopeptide (asialo-glycanAsn) isolated from serotransferrin is described, and the signals of the anomeric protons, the mannose-H-2 protons and the N-acetyl methyl groups were analysed.
TL;DR: A series of organotin and organolead compounds were fed to male and female weanling rats for 2 weeks at dietary levels of 0, 50, or 150 ppm, in order to evaluate their toxic effects, with special emphasis on the thymus and peripheral lymphoid organs.
TL;DR: A rapid and efficient method for the separation of (phospho)lipids by high-performance liquid chromatography using n-hexane-2-propanol-water mixtures as the solvent system is described and separation of molecular species can also be achieved, as is shown for phosphatidylcholines and sphingomyelins.
Journal Article•
TL;DR: In this paper, the masses and number of neutral weakly interacting particles are derived using cosmological arguments, and it is shown that no such particles with a mass between 120 eV and 3 GeV can exist within the usual big band model.
TL;DR: In breast cancer patients in Rotterdam and The Hague those with metastases in axillary nodes were significantly heavier but not taller than those without nodal involvement, suggesting a hormonal factor related to body weight and/or height might be responsible for the increased incidence and the more rapid course of breast cancer in women with a large body mass.
Abstract: A study was made in the cities of Rotterdam and The Hague, the Netherlands, and in Aichi prefecture, Japan, to assess the effect of weight and height (and their combinations) on the age-specific incidence of breast cancer. It is based on a comparison between 1006 cases of breast cancer and 4201 women from the general population, 35–69 years old. The results suggest that about one-half of the differences in incidence between the regions in Holland and Japan can be attributed to differences in body weight and height. In breast cancer patients in Rotterdam and The Hague those with metastases in axillary nodes were significantly heavier but not taller than those without nodal involvement. A hormonal factor related to body weight and/or height might be responsible for the increased incidence and the more rapid course of breast cancer in women with a large body mass.
TL;DR: In this paper, the interaction of methane with Ni(110) was studied with AES, LEED and ellipsometry, and the carbon coverages were derived from Auger spectra by calibration with ellipsetry.
TL;DR: Although significant variations in catecholamine release over time were observed, they did not reflect a fixed autonomic periodicity and are considered to be specific as no change in release was observed even during the drinking vigorous response induced by angiotensin.
Abstract: The release of endogenous noradrenaline (NA) and dopamine (DA) from various sites in the hypothalamus was determined in unanesthetized, freely moving rats by means of a push-pull perfusion technique in combination with a sensitive radiochemical assay. The perfusate was collected continuosly over 10-min periods for 4 to 8 hr. Patterns of feeding, drinking, grooming, and locomotor activity were recorded during the perfusion experiments. Release patterns and behavior recordings were analysed by tests of serial correlation. Although significant variations in catecholamine release over time were observed, they did not reflect a fixed autonomic periodicity. Release from the medial hypothalamus was measured in rats which had been deprived of food for 16 hr and were subsequently given free access to food. Before food presentation, mean NA release over 10-min periods was consistently higher than during satiety. Mean NA and DA release over 10-min periods before, during and after the occurence of feeding, drinking or grooming were calculated for the dorsomedial, perifornical, subfornical, and anterolateral hypothalamus of freely feeding rats. During feeding, NA (but not DA) release from the dorsomedial and perifornical areas was significantly elevated (40–50%) when compared with pre- or postfeeding values. An increase in catecholamine release was not observed during drinking or grooming. In addition, NA release from the anterolateral area correlated with locomotor activity. The enhancement of NA release from the perifornical area during feeding is considered to be specific as no change in release was observed even during the drinking vigorous response induced by angiotensin.
TL;DR: Binding of both phosphatidylinositol and phosph atidylcholine to the beef brain protein was shown, indicating that this protein can catalyse a net transfer of phosphatIDylinopsitol.
TL;DR: In this article, the electron concentration and mobility in polycrystalline In 2 O 3 have been measured as a function of temperature and partial oxygen pressure, in the temperature range from 25 to 700°C.
TL;DR: In this paper, the C -type rare earth structure of In 2 O 3 is compared with the fluorite structure and the stability of the structure is discussed based on DTA and X-ray work and electron microscopy.
TL;DR: The results indicate that the position of the cis-double bond in the fatty acid chain is very important in this respect in systems in which cholesterol increased the temperature dependence of the water permeation.
TL;DR: The primary structure of porcine pancreatic phospholipase A2 has been reinvestigated and shows a high degree of homology with the amino acid sequence of snake venom and horse pancreas phospholine A2.
TL;DR: It is concluded that the long-term effect of vasopressin on learned behavior is of a rather general nature and is most probably due to facilitated memory consolidation processes.