Showing papers by "University of Geneva published in 1981"
TL;DR: Compared to conventional Epon embedding of glutaraldehyde fixed tissue, the low temperature embedding method with Lowicryl K4M resulted in a superior preservation of the general cellular fine structure, particularly in the Golgi apparatus.
Abstract: The recently developed low temperature embedding procedure with the resin Lowicryl K4M (Carlemalm E, Garavito M, Villiger W: Proc 7th Eur Cong Electron Microsc, 1980, p 656; Garavito M, Carlemalm E, Villiger W: Proc 7th Eur Cong Electron Microsc, 1980, p 658) was tested for its suitability for embedding of glutaraldehyde-fixed rat pancreatic tissue and for postembedding staining of thin sections with the protein A-gold (pAg) technique (Roth J, Bendayan M, Orci L: J Histochem Cytochem 26:1074, 1978) for amylase. Compared to conventional Epon embedding of glutaraldehyde fixed tissue, the low temperature embedding method with Lowicryl K4M resulted in a superior preservation of the general cellular fine structure, particularly in the Golgi apparatus. For low temperature embedded tissue, the quantitative evaluation of the immunocytochemical labeling for amylase showed a more specific staining of the rough endoplasmic reticulum, the Golgi apparatus, and the zymogen granules. This was due to a significant loweri...
741 citations
TL;DR: In this article, three scenarios leading to turbulence in theory and experiment are outlined, and the respective mathematical theories are explained and compared, and three different models of turbulence are discussed. But none of the scenarios are discussed in detail.
Abstract: Three scenarios leading to turbulence in theory and experiment are outlined. The respective mathematical theories are explained and compared.
740 citations
TL;DR: Vimentin has been demonstrated in a smooth muscle cell present in the body and it is proposed that the intermediate filament and actin composition of vascular smooth muscle cells reflects a differentiation pathway separate from that of other smoother muscle cells and may be related to special functions and pathological disorders of blood vessels.
Abstract: Smooth muscle cells of the digestive, respiratory, and urogenital tracts contain desmin as their major, if not exclusive, intermediate-size filament constituent and also show a predominance of gamma-type smooth muscle actin. We have now examined smooth muscle tissue of different blood vessels (e.g., aorta, small arteries, arterioles, venules, and vena cava) from various mammals (man, cow, pig, rabbit, rat) by one- and two-dimensional gel electrophoresis of cell proteins and by immunofluorescence microscopy using antibodies to different intermediate-sized filament proteins. Intermediate-sized filaments of vascular smooth muscle cells contain abundant amounts of vimentin and little, if any, desmin. On gel electrophoresis, vascular smooth muscle vimentin appears as two isoelectric variants of apparent pI values of 5.30 and 5.29, shows the characteristic series of proteolytic fragments, and is one of the major cell proteins. Thus vimentin has been demonstrated in a smooth muscle cell present in the body. Vascular smooth muscle cells are also distinguished by the predominance of a smooth muscle-specific alpha-type actin, whereas gamma-type smooth muscle actin is present only as a minor component. It is proposed that the intermediate filament and actin composition of vascular smooth muscle cells reflects a differentiation pathway separate from that of other smooth muscle cells and may be related to special functions and pathological disorders of blood vessels.
469 citations
Journal Article•
TL;DR: It can be seen that, during neoplastic transformation, there are no major changes in the synthesis of the type of intermediate filament proteins when compared to normal tissues.
Abstract: Forty-three tumors were investigated by means of immunofluorescence with the use of antibodies against the following different classes of intermediate-sized (10 nm) filament proteins: 1) cytokeratins, 2) vimentin, and 3) desmin. In general, the immunologic features of tumor-cell intermediate filaments are those present in their tissue of origin. It can be seen, therefore, that, during neoplastic transformation, there are no major changes in the synthesis of the type of intermediate filament proteins when compared to normal tissues. Immunologic identification of these proteins furnishes the surgical pathologist with a quick and clear-cut way to differentiate tumors of mesenchymal origin from epithelial neoplasms, and in particular to distinguish between malignant lymphomas and lymph node metastases of undifferentiated carcinomas.
400 citations
TL;DR: This article reviews data on one aspect of the magic bullet concept, the use of radiolabelled antibodies as tracers for tumour localization, and discusses the very recent clinical use of (131)I-labelled Mabs against carcinoembryonic antigen.
386 citations
TL;DR: The results demonstrate that nuclei from ICM cells of the mouse blastocyst are not yet restricted in their differentiation capacities but rather remain developmentally equivalent to the totipotent zygote nucleus.
267 citations
TL;DR: It is found that the sweet taste of a saccharin solution reliably triggers a rapid cephalic phase insulin response (CPIR), in the absence of any significant change of glycemia, and its lack can result in pathological oral glucose tolerance and on the other hand its exaggeration might contribute to the behavioral reaction to highly palatable sweet food and the resulting development of dietary obesity.
Abstract: Using chronically catheterized, freely moving male Wistar rats, we have shown that the sweet taste of a saccharin solution reliably triggers a rapid cephalic phase insulin response (CPIR), in the absence of any significant change of glycemia. To establish the neural mediation of this reflex response we used rats that were cured from streptozotocin diabetes by intrahepatic islet-transplantation as a denervated B-cell preparation. The complete lack of any saccharin-induced CPIR in these rats suggests that it is indeed mediated by the peripheral autonomic nervous system, and that the insulin-stimulating gastrointestinal hormones are not involved in this response. It was further found that this reflex insulin secretion is not easily extinguishable and thus might have an unconditioned component. To investigate the central neural pathways involved in this reflex response we used both electrophysiological methods in anesthetized and semi-micro CNS manipulations in freely moving rats. On the basis of our preliminary results, and several reports, using the decerebrate rat preparation for measuring behavioral or saliva secretory oral taste reactivity, it appears that CPIR might be organized at the brain stem/midbrain level, receiving strong modulatory influences from the diencephalon. But much further work has to be done to establish the central nervous circuitry. Finally, in two experiments, aiming at the question of how important and physiologically relevant the CPIR might be, we found that, on one hand, its lack can result in pathological oral glucose tolerance and on the other hand its exaggeration might contribute to the behavioral reaction to highly palatable sweet food and the resulting development of dietary obesity.
220 citations
TL;DR: It is concluded that early postimplantation embryonic development, up to mesoderm formation, is characterized by the exclusive presence, in both embryonic ectoderm and proximal endoderm, of differentiated epithelial cells containing desmosome-cytokeratin filament complexes and that other types of intermediate-sized filaments are not yet expressed.
218 citations
TL;DR: In some animals, light labelling in the organum vasculosum laminae terminalis and in the subfornical organ was observed and no labelled neurones could be detected in the spinal cord.
206 citations
TL;DR: Two predictions of this model, namely, that the requirement of continuous protein synthesis for genome replication is not at the level of the initiation of the genome chains but at thelevel of the suppression of the leader RNA termination signal, have been tested experimentally and the results found to be consistent with the above model.
203 citations
TL;DR: The plasmid pBR325 carries between the Cmr and Tcr genes a 482 bp sequence which duplicates, in the opposite orientation, a section pf pBR322 located at the end of the tcr gene.
TL;DR: In this article, a theory of stochastic calculus of variations is presented which generalizes the ordinary calculus of variation to stochastically processes and generalizations of the Euler equation and Noether's theorem are obtained.
TL;DR: An operational computer algorithm is proposed which has been successfully tested with several economic models, some of which contain more than 10 000 circuits, and is analogous to the hierarchical order given by the reduced graph of a recursive system.
TL;DR: In this article, it was shown that the same is true for 1-pf analytic maps from ℂ n ≥ 2 to ℆ n ≥ 3, whose restriction to n is real, with the asymptotic geometric ratio 1 /4.6692.
Abstract: Infinite sequences of period doubling bifurcations in one-parameter families (1-pf) of maps enjoy very strong universality properties: This is known numerically in a multitude of cases and has been shown rigorously for certain 1-pf of maps on the interval. These bifurcations occur in 1-pf of analytic maps at values of the parameter tending to a limit with the asymptotically geometric ratio 1 /4.6692 ....In this paper we indicate the main steps of a proof that the same is true for 1-pf of analytic maps from ℂ
n
to ℂ
n
, whose restriction to ℝn is real.
TL;DR: It is concluded that CaBP represents a marker for selected neurons in the central nervous system of chick.
TL;DR: The DNA sequence of a complete hsp70 † gene of the 87A7 type and of the adjacent regions from both variants, extending to 1·2 × 10 3 bases upstream from the start of the messenger coding region, is presented.
TL;DR: Results indicated that spindle density was the same in stages 2, 3, and 4, and was much lower in rapid eye movement (REM) sleep, while K potentials were less abundant than spindles and exhibited a much smaller individual variability.
Abstract: We studied sleep spindle activity in ten normal young subjects, five males and five females. The subjects were recorded on magnetic tapes according to standard procedures, and the tapes were scored automatically by a system described previously. Spindle activity was analyzed on the C4-T4 lead of electroencephalogram, using a bandpass filter and discrimination of the integrated output of the filter. Results indicated that spindle density was the same in stages 2, 3, and 4, and was much lower in rapid eye movement (REM) sleep. In stage 2, K potentials were less abundant than spindles and exhibited a much smaller individual variability. Whereas spindle density was very stable across two nights in the same subject, there was wide variation between subjects. In addition, there was a sex difference; female subjects presented more than twice as many spindles as males. The density of spindles during non-REM sleep was constant throughout the recording and did not show any cyclic variation.
TL;DR: In this article, a low-temperature X-ray diffraction study was undertaken in order to fix the compositional limit of the tetragonal phase of the Nb-Sn A15 phase.
Abstract: Bulk samples covering the entire homogeneity range of the Nb-Sn A15-phase were prepared by a new method: levitation melting under high argon pressure. The variations of the lattice parameter, superconducting transition temperature, resistivity and critical field slope were measured as a function of composition. A low-temperature X-ray diffraction study was undertaken in order to fix the compositional limit of the tetragonal phase. The theoretical expectations for the critical field slopes at the transition temperature, Tc, based on actually-observed alloy parameters, were found to be in good agreeement with measured values.
TL;DR: The data suggest that human pregnancy is accompanied by a resetting of the threshold for vasopressin secretion to a lower Posm, and also suggest that AVP excretion is suppressed by water loading and normal concentration and dilution despite a lower plasma tonicity.
TL;DR: The characterized frameshift mutations in lacI described here are useful for constructing systems to detect other frameshifts and deletion mutations.
TL;DR: RuCl 2 (PPh 3 ) 3 catalyzes the oxidation of primary alcohols to carbonyi compounds by iodosylbenzene and that of aldehydes to carboxylic acids as discussed by the authors.
TL;DR: Starting from the enantiomerically pure monoterpenes (+)-pulegone (3), (+)-limonene (7), (−)-β-pinene (9), (+-) and (−)-camphor (13) or (+)-cholestenone (11) the chiral alcohols 4, 5, 6, 8, 10, 12, 14, 15, 16, 17 et 18 were prepared; their acrylates II underwent a TiCl4-promoted Diels-Alder addition to cyclopentadiene (Sche
Abstract: Starting from the enantiomerically pure monoterpenes (+)-pulegone (3), (+)-limonene (7), (−)-β-pinene (9), (+)- and (−)-camphor (13) or (+)-cholestenone (11) the chiral alcohols 4, 5, 6, 8, 10, 12, 14, 15, 16, 17 et 18 were prepared; their acrylates II underwent a TiCl4-promoted Diels-Alder addition to cyclopentadiene (Scheme 3, Table) giving in a predictable manner either the (2R)- or the (2S)-adducts III with 63 to 88% asymmetric induction.
TL;DR: The results suggest a role for vitamin D--dependent calcium binding protein in intracellular calcium metabolism rather than a direct involvement in membrane-mediated calcium reabsorption in the avian kidney.
Abstract: A vitamin D--dependent calcium binding protein in the chick kidney that was detected by immunocytochemical techniques was localized exclusively in the distal convoluted tubule, the initial collecting tubule, and the early part of the collecting tubule. The intercalated (mitochondria-rich) cells in these tubular segments were negative for the calcium binding protein. Subcellularly, the protein was found in the cytosol and the nucleus of the tubular cells. The results suggest a role for vitamin D--dependent calcium binding protein in intracellular calcium metabolism rather than a direct involvement in membrane-mediated calcium reabsorption in the avian kidney.
TL;DR: It has been proved that the one axoneme type of the spermatozoon, observed in Tetraphyllidea, Phyllobothriidae arises from the two axonemes type by early abortion of the second axonemo, and two hypothesis can be forwarded to explain the relationships between the TetraphllideA, Proteocephalidea and Cyclophyllidea.
Abstract: The comparison of the ultrastructure of spermatozoa in Cestodes from seven different orders shows that they have the same general pattern of organization. The main common features are following: (a) a long thread-like body; (b) an elongated nucleus; (c) cortical microtubules underlying plasma membrane; (d) the absence of mitochondria and of a typical acrosome. The mode of spermatozoon differentiation indicates an inversion of the polarity. The number of axonemes of the 9 + "1" pattern, characteristic of the platyhelminthes, allow us to distinguish two types of spermatozoa among cestodes: --The "two-axonemes"-type is considered as primitive as it has also been found in the free-living platyhelminths. This type has been observed in the Pseudophyllidea, Proteocephalidea, Tetrarhynchidea and Tetraphyllidea (Onchobothriidae). --The "one-axoneme"-type has been found in the Cyclophyllidea, Caryophyllaeidea, Diphyllidea and Tetraphyllidea (Phyllobothriidae). It has been proved that the one axoneme type of the spermatozoon, observed in Tetraphyllidea, Phyllobothriidae arises from the two axoneme type by early abortion of the second axoneme. In all the tetraphyllidean species studied so far, we found an helicoidal body forming so-called "crested body" or "spiral crest" at the proximal end of the spermatozoon, which is opposite to the nuclear part. This division of the cestodes into two groups, according to the number of axonemes in the spermatozoon is compared with the phylogenetic diagrammes of Cestoda proposed by Freeman (1973) and Euzet (1974). As result, two hypothesis can be forwarded to explain the relationships between the Tetraphyllidea, Proteocephalidea and Cyclophyllidea. The importance of data on the cestode spermatozoa as a criterion in analysis of cestode phylogenesis is drawn and discussed.
TL;DR: In this article, the mass degree of freedom of relativistic systems has been studied in the classical and quantum Gibbs ensembles for equilibrium statistical mechanics, and it has been shown that in the non-relativistic limit the mass distribution is sufficiently sharp, the thermodynamical effects of this multiplicity will not be large.
TL;DR: Methods of orders 5 and 6 are derived which require one evaluation of the Jacobian and oneLU decomposition per step and are A-stable (or stiffly stable) and nevertheless do not require the solution of nonlinear systems of equations.
Abstract: This paper deals with the solution of nonlinear stiff ordinary differential equations. The methods derived here are of Rosenbrock-type. This has the advantage that they areA-stable (or stiffly stable) and nevertheless do not require the solution of nonlinear systems of equations. We derive methods of orders 5 and 6 which require one evaluation of the Jacobian and oneLU decomposition per step. We have written programs for these methods which use Richardson extrapolation for the step size control and give numerical results.
TL;DR: In this paper, the trans-8-phenyl-menthyl enoates were added to the cis-crotonate to obtain enantiomerically pure β-substituted alkanoic acids.
Abstract: 1,4-Additions of PhCu · BF3, n-Bu · BF3 and MeCu · BF3 to the trans-8-phenyl-menthyl enoates 1 proceeded with high chiral induction. Saponification of the resulting esters 2 gave the corresponding enantiomerically pure β-substituted alkanoic acids 3 and the recovered (−)-8-phenylmenthol in good overall yields. Analogous additions to the cis-crotonate 1 led preferentially to the acids 3 enantiomeric to those obtained from the trans-crotonate 1, although with lower selectivity. A stereochemical model is proposed consistent with the observed results (Scheme 2, Table).
TL;DR: It is concluded that the involvement of the ventromedial bypothalamus in the activation of brown adipose tissue provided a possible anatomical clue concerning pathways connecting thermal and weight regulations.
Abstract: The metabolic responses to electrical nerve stimulation, norepinephrine or octanoate additions were studied using continuous monitoring of NAD(P)H/NADP redox state by reflexion spectrophotometry of interscapular brown adipose tissues from control and ventromedial hypothalamic (VMH) lesioned rats. The responses to these stimuli were all greatly decreased already 3 days after VMH lesions, indicating a reduced cell capacity to oxidize free fatty acids. Measurements of interscapular brown adipose tissue composition 4–5 weeks after VMH lesions showed a decrease of both DNA concentration and total content, indicating some tissue involution.
TL;DR: In this paper, Lysergic acid was synthesized from 4-hydroxymethyl-1-tosylindole by a sequence of 9 steps and the crucial thermolysis involved the in situ generation of the transient diene III which undergoes an intramolecular cycloaddition to a C, N-double bond at 200° and at low stationary concentration of III.
Abstract: (±)-Lysergic acid (1) has been synthesized from 4-hydroxymethyl-1-tosylindole (2) by a sequence of 9 steps. The crucial thermolysis 9 10 involves the in situ-generation of the transient diene III which undergoes an intramolecular cycloaddition to a C, N-double bond at 200° and at low stationary concentration of III.