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Showing papers by "University of Geneva published in 1972"


Journal ArticleDOI
Giulio Gabbiani1, Bernard Hirschel1, Ryan Gb1, P. R. Statkov1, G. Majno1 
TL;DR: The view that, under certain conditions, fibroblasts can differentiate into a cell type structurally and functionally similar to smooth muscle and that this cell, the "myo-fibroblast," plays an important role in connective tissue contraction is supported.
Abstract: Contracting granulation tissues contain fibroblasts that develop characteristics typical of smooth muscle: (a) They contain an extensive cytoplasmic fibrillar system. (b) They show immunofluorescent labeling of their cytoplasm with human anti-smooth muscle serum. (c) The nuclei show complicated folds and indentations, indicative of cellular contraction. (d) There are cell-to-cell and cell-to-stroma attachments. (e) It is possible to extract similar quantities of actomyosin (having the same adenosine triphosphatase activity) from granulation tissue and from pregnant rat uterus. (f) Strips of granulation tissue, when tested pharmacologically in vitro, behave similarly to smooth muscle. All these data support the view that, under certain conditions, fibroblasts can differentiate into a cell type structurally and functionally similar to smooth muscle and that this cell, the "myo-fibroblast," plays an important role in connective tissue contraction.

780 citations


Journal ArticleDOI
TL;DR: The ultrasonic attenuation in glasses at low temperatures is calculated using the model proposed by Anderson, Halperin, and Varma as discussed by the authors, and it is found that the resonant absorption of sound by the localized two-level systems saturates and can be observed only if the sound amplitude is extremely small.
Abstract: The ultrasonic attenuation in glasses at low temperatures is calculated using the model proposed by Anderson, Halperin, and Varma It is found that the resonant absorption of sound by the localized two-level systems saturates and can be observed only if the sound amplitude is extremely small A second contribution to the sound absorption is derived which arises from the relaxation of the localized excitations and does not saturate Qualitative agreement with recent measurements of the ultrasonic attenuation in fused silica is obtained

381 citations


Journal ArticleDOI
TL;DR: Two methods have been used to determine the origin and direction of chromosome replication in Escherichia coli: gradient of marker frequency and sequence of replication in synchronized cultures, and DNA-DNA hybridization was used to assay for gene dosage.

259 citations


Journal ArticleDOI
TL;DR: The simultaneous use on mouse lymphoid suspensions of heterologous antisera directed against thymus-derived (T) cell mouse-specific lymphocyte antigen and brain-associated theta antigen and MBLA surface antigens allowed direct proof of the different specificity of these antisona by double immunofluorescence (IF) staining with selective visualization of fluorochromes.
Abstract: The simultaneous use on mouse lymphoid suspensions of heterologous antisera directed against thymus-derived (T) cell mouse-specific lymphocyte antigen and brain-associated theta antigen (MSLA and BAtheta) or thymus-independent (B) cell mouse-specific bone marrow-derived lymphocyte antigen (MBLA) surface antigens allowed direct proof of the different specificity of these antisera by double immunofluorescence (IF) staining with selective visualization of fluorochromes. These antisera and antisera against mouse Ig and its different types of chains were then used with technique of either double IF staining or IF combined with radioautography, allowing the following conclusions: (a) Surface Ig (sIg) was found exclusively on B cells and never on T cells, but not all B cells had sIg. Cells containing detectable amounts of Ig were MBLA+, but had less sIg than other B cells or none at all. There was evidence for the existence of a significant number of MBLA+ lymphocytes, neither bearing nor containing detectable Ig. (b) micro-Chains were the most frequent but not the only heavy chains found on spleen cells; however, it could not be decided with the technique used, if a single cell can bear more than one type of heavy chain. No cell containing gamma-chains was found to bear surface micro-chains, although a very few cells containing both micro- and gamma-chains were observed. (c) The antigen-binding cells detected after immunization with bacteriophage T4, bovine serum albumin, Maia squinado hemocyanin, and sheep erythrocytes were analyzed for MSLA, MBLA or sIg using double IF, a combination of IF and radioautography, or inhibition of "rosette" formation. Practically all the antigen-binding cells detected were MSLA-, MBLA+, sIg+. (d) More B cells than T cells were found among short-lived lymphoid cells labeled by repeated in vivo injections of tritiated thymidine, but the results did not support a simplified concept equating T cells to long-lived and B cells to short-lived lymphocytes. (e) Cells dividing rapidly in the lymph nodes draining the sites of immunization with various antigens were predominantly T cells 2 days after immunization and in majority B cells a few days later. (f) Incubation of lymphoid cells at 37 degrees C with rabbit anti-mouse Ig or anti-kappa chains led to complete disappearance of sIg and to decrease of MBLA ("antigenic modulation"). In the same conditions, anti-MBLA gave partial modulation of MBLA and of sIg; MBLA, however, reappeared much faster than sIg. No modulation of T cell surface antigens by the appropriate antisera was observed. Cell treatment with Pronase could remove MBLA, sIg, MSLA, and BAtheta, which reappeared within a few hours. Neuraminidase treatment was without detectable effect on these antigens.

142 citations


Journal ArticleDOI
TL;DR: Pancreatic cells from neonatal rats, isolated by repeated exposure to a mixture of trypsin and collagenase, were cultured in monolayer for periods up to 19.5 days and the major problem encountered was the rapid proliferation of fibroblastoid cells which tended to overgrow the culture.
Abstract: Pancreatic cells from neonatal rats, isolated by repeated exposure to a mixture of trypsin and collagenase, were cultured in monolayer for periods up to 19.5 days. This preparation was characterized by: (1) light microscopy combined with morphometric analysis; and (2) measurements of immunoreactive insulin (IRI) and protein content of cultured cells and of the amounts of IRI released into the culture medium. The major problem encountered was the rapid proliferation of fibroblastoid cells which tended to overgrow the culture. The decantation of the primary cell suspension after 14 hrs of culture produced a preparation enriched in epithelioid cells, which appeared as clusters. Contained in these clusters were aldehyde-thionin positive cells, presumably B cells. The number of clusters of epithelioid cells did not change over an 8.5 day culture period, but the size of the individual clusters diminished with time. The protein content of cultured cells, which probably reflects the degree of contamination by fib...

124 citations


Journal ArticleDOI
TL;DR: The multiple signals in the 3D region of seven lanthanum(III) compounds are explained by the possibility of simultaneous transfer of an electron from the neighbour atoms to the empty 4f shell during the ionization.

115 citations


Journal ArticleDOI
TL;DR: A number of useful inequalities which are known for the trace on a separable Hilbert space are extended to traces on von Neumann algebras in this paper, including the Golden rule, Holder inequality, and some convexity statements.
Abstract: A number of useful inequalities, which are known for the trace on a separable Hilbert space, are extended to traces on von Neumann algebras. In particular, we prove the Golden rule, Holder inequality, and some convexity statements.

102 citations


Journal ArticleDOI
TL;DR: The results suggest that protein synthesis is required for maturation while RNA synthesis is not and some two-step mechanism of hormonal action may be envisioned.

98 citations


Journal ArticleDOI
TL;DR: The binding of Ca 2+ to muscular parvalbumins from hake and frog has been measured using the 45 Ca-Chelex partition method and results indicate that these proteins have two high affinity sites and 3–6 sites with lower affinity for this ion.

97 citations


Journal ArticleDOI
TL;DR: In vitro Escherichia coli strain B-specific modification of the replicative form of bacteriophage fd DNA is accompanied by the methylation of certain adenine moieties to form N-6-methyladenine, and it is concluded that the B-modification and theB-restriction enzyme react with the same sites on the substrate DNA.

92 citations


Journal ArticleDOI
TL;DR: Electron microscopy confirmed the presence of deformed nuclei in such vessels and support the concept that vascular leakage, caused by histamine-type mediators, is dependent upon endothelial contraction.
Abstract: Electron microscopic studies have previously shown that histamine-type mediators of vascular leakage induce: (1) the appearance of gaps between venular endothelial cells; and (2) deformation of endothelial nuclei, with multiple deep infoldings. It has been postulated that these changes (and the leakage) are due to contraction of endothelial cells. The present paper has investigated this hypothesis by examining the effects of bradykinin and histamine on living rat mesenteric venules. Within 2–5 minutes after application of the mediator, some endothelial cells began to bulge; obvious bulging lasted for about 5 minutes and then subsided slowly; by 20–30 minutes after application of the mediator, the cells were again flattened. This time-course of bulging and flattening corresponded with the rise and fall in vascular permeability, as shown by carbon labeling. Electron microscopy confirmed the presence of deformed nuclei in such vessels. These observations support the concept that vascular leakage, caused by histamine-type mediators, is dependent upon endothelial contraction.

Journal ArticleDOI
01 Aug 1972-Chest
TL;DR: It is postulated, on the basis of morphometric data, that the diffusion capacity of the air-blood barrier should be highly reduced in patients given 60 percent to 100 percent oxygen for periods longer than three days.

Journal ArticleDOI
TL;DR: There is good promise that further, deeper studies will finally reveal Neurospora to have one of the most highly integrated control systems for eucaryotic sporogenesis when considered as a model of cell differentiation.
Abstract: Thus, from the gene to the character, and back from the typical character (standard conidium) to the gene, we have traced a few of the biosynthetic pathways which must obligatorily be triggered (switched on or off) to effect the transition from the relatively undifferentiated vegetative hyphae through the fertile, conidiogenous hyphae to the differentiated cells, the conidia. There is good promise that further, deeper studies will finally revealNeurospora to have one of the most highly integrated control systems for eucaryotic sporogenesis when considered as a model of cell differentiation.

Journal ArticleDOI
TL;DR: Evidence is presented that T1 lymphocytes represent "virgin" T cells, T2 "activated," and T3 "differentiated" lymphocytes, and that SIg-bearing cells appeared to be identical with MBLA+ cells, except that sIg was less easily detectable on large blasts, and only very rarely observed on plasma cells.
Abstract: The ultrastructural features of B-, T-, and surface Ig(sIg)-bearing cells have been studied on cell suspensions from lymphoid organs of mice at different stages of immunization. The cells were identified by exposure to rabbit antibodies against mouse-specific lymphocyte antigens (MSLA) or brain-associated theta antigen (BAtheta) for T cells, mouse-specific bone marrow-derived lymphocyte antigens (MBLA) for B cells, and mouse Ig for sIg-bearing cells. The rabbit antibodies fixed on the cell surfaces were detected by peroxidase-labeled sheep anti-rabbit Ig antibodies or by a "bridge" technique using southern bean mosaic virus or bacteriophage T4 as the final markers. In some experiments, short-lived lymphoid cells were labeled in vivo with repeated tritiated thymidine and the ultrastructural detection of their surface antigens was combined with radioautography. MBLA+ lymphoid cells showed a whole range of ultrastructural patterns. Most were small and medium-sized lymphocytes with a clear cytoplasm containing mono- and polyribosomes, but they comprised also blasts and large cells with various amounts of endoplasmic reticulum, as well as plasma cells at different stages of maturation. sIg-bearing cells appeared to be identical with MBLA+ cells, except that sIg was less easily detectable on large blasts, and only very rarely observed on plasma cells. MSLA+ and BAtheta+ cells fell into three categories. One of them (T(1) cells) consisted of small to medium-sized lymphocytes with a clear cytoplasm and few organelles, mostly monoribosomes. A second consisted of large cells (T(2) cells) characterized by numerous polyribosomes often in a "rosette"-like pattern, occasional dark, membrane-bound granules, and a developing "filamentous network." The third, very characteristic type, (T(3) cells) was represented by dark small to medium-sized lymphocytes, usually containing large amounts of closely packed ribosomes and showing a striking accumulation of filamentous network, often condensed in large areas devoid of cell organelles. This filamentous network appeared to correspond to the cytochalasin B-sensitive system of microfilaments found in other cells and considered to be one of the contractile elements of the cell. The T(3) lymphocytes showed frequently vesicles suggestive of a strong pinocytic activity, and assumed a variety of shapes, including uropods. Evidence is presented that T(1) lymphocytes represent "virgin" T cells, T(2) "activated," and T(3) "differentiated" lymphocytes.

Journal ArticleDOI
TL;DR: For instance, this article found that children between the ages of 2 years, 10 months and 7 years were asked to guess the meaning of 30 deviant three-word utterances, resembling utterances spontaneously produced by very young children.


Journal ArticleDOI
01 Aug 1972-Cancer
TL;DR: It is suggested that epithelioid sarcoma may be a variant of this tumor, which consisted of a collagen‐rich fibrous stroma with nests of large epithelial‐like cells with acidophilic cytoplasm giving the neoplastic tissue a biphasic pattern.
Abstract: Two cases of “epithelioid sarcoma” were studied by light and electron microscopy. In both cases, the tumor consisted of a collagen‐rich fibrous stroma with nests of large epithelial‐like cells with acidophilic cytoplasm, giving the neoplastic tissue a biphasic pattern. The ultrastructural study showed that the tumor cells were of three types: “clear” and “dark” cells (recalling those of the synovium and synovial sarcoma) with distorted nuclei and abundant cytoplasm, and a less common, more immature cell. The histologic and ultrastructural features of the neoplastic cells, as well as those of the ground substance, indicate that the tumor is neither of chrondroid nor of histiocytic origin. The cells of the epithelioid islands are similar to the stromal component of synovial sarcoma. It is suggested that epithelioid sarcoma may be a variant of this tumor.

Journal ArticleDOI
TL;DR: In this article, the effects of the free trade period which began around 1860 on three then "less developed" countries: France, Germany and Italy, and on the "developed" country: Great Britain, were analyzed empirically.

Journal ArticleDOI
TL;DR: A positive, statistically significant correlation was found between the concentrations of cathepsin D in gingival exudate and the depths of the periodontal pockets, as well as the mean percentage of bone loss, which substantiate a possible role of lysosomal enzymes in the pathogenesis of periodontitis.

Journal ArticleDOI
TL;DR: The role of stimulated T cells in the induction of B mitoses was shown by the incapacity of T-depleted spleen cells to be stimulated by PHA or in primary or secondary MLC, and the restoration of the mitotic response of B cells to PHA.
Abstract: Spleen cell cultures of radiation chimeras (thymectomized, lethally irradiated mice repopulated with bone marrow cells and thymocytes bearing different chromosomal markers) were stimulated by phytohemagglutinin (PHA) and F(1) allogeneic spleen cells. Karyotypic analyses showed a marked predominance of T mitoses on the 2nd and 3rd days of culture followed by a strong predominance of B mitoses on the 4th and 5th days. Analysis of cells undergoing their first mitoses showed that the majority of T mitoses on day 3 resulted from continuous T cell division, and that most cells entering their first mitoses at that time were of B type. Mixed lymphocyte cultures (MLC) of chimeras immunized against allogeneic spleen cells showed sometimes, but not always, a response different from "primary" MLC, with an earlier and stronger predominance of BM mitoses. The role of stimulated T cells in the induction of B mitoses was shown by (a) the incapacity of T-depleted spleen cells to be stimulated by PHA or in primary or secondary MLC, and (b) the restoration of the mitotic response of B cells to PHA by adding to the T cell-depleted culture either a very small number of T cell (identified by their different karyotype: "in vitro chimeras") or the cell-free supernatant of a 24 hr MLC.

Journal ArticleDOI
TL;DR: It is suggested that the in vitro transformation from the 6- to the 6 + 1-type of morphological unit is correlated with the cleavage of protein components which accompany the normal assembly (Laemmli, 1970), and may mimic an in vivo structural transformation.

Journal ArticleDOI
TL;DR: In this article, the A-specific modification is brought about by DNA methylation and the sAo mutation not only abolished the affinity for a-specific restriction, but also for A specific modification.
Abstract: Bacteria with A-specific restriction plate unmodified phage λ with an efficiency of 10-2. One mutational event can produce restriction insensitive (sAo) mutants of λ. These differ from the original sA form of λ by no other property than their response to A-host specificity. Two-parental phage crosses involving sA and sAo, respectively, as non-selective marker allowed to map sA between genes cII and O. These data indicate that sA is the only site on λDNA with affinity for A-specific restriction. λDNA is thus an interesting substrate in in vitro A-specific restriction and modification. Using an assay based on the infectivity of λDNA on helper-infected bacteria, A-specific modification activity was found in partially purified sonicates of bacteria with A-host specificity. In parallel to modification, 3H-methyl label from s-adenosylmethionine, the only cofactor required for modification, was transferred to unmodified λDNA. No association of radioactivity was observed in control experiments with DNA from either modified λ·A or from aλsAo mutant. These data suggest that A-specific modification is brought about by DNA methylation and that the sAo mutation not only abolished the affinity for A-specific restriction, but also for A-specific modification.

Journal ArticleDOI
TL;DR: The question of why the closing-in sign may be found with such a surprising similarity both in the normal evolutive pattern and in the retrogenic dissolutive symptomatology is discussed.

Journal ArticleDOI
TL;DR: By exposing large areas of cellular membranes, the technique of freeze etching retrieves the threedimensional image lost by sectioning, and this communication will present data from freezeetched preparations showing clear images of fenestrae in the ER cisternae of the exocrine pancreatic cells of several species.
Abstract: Since its original description, the endoplasmic reticulum (ER) has been considered to be a system of flattened cisternae interconnected with canalicular bridges or tubules (1) . This three-dimensional model of the ER was inferred mainly from images obtained on spread cells in toto where the ER appears as a continuous branching network . Subsequently, Palade (2) reported that the ER cisternae were not only branched and connected with bridges but also fenestrated . However, since thin sections for electron microscopy give only a limited sampling of an entire ER sheet, the number and the distribution of the fenestrae could not be accurately assessed . By exposing large areas of cellular membranes, the technique of freeze etching retrieves the threedimensional image lost by sectioning, and this communication will present data from freezeetched preparations showing clear images of fenestrae in the ER cisternae of the exocrine pancreatic cells of several species .

Journal ArticleDOI
10 Nov 1972-Science
TL;DR: Frogs were injected intraperitoneally with bacteria, and the RNA of the brains (which have protective barriers against the bacteria used) was extracted and part of the RNA was bacterial RNA apparently resulting from the transcription of DNA transferred from bacteria to the brain cells.
Abstract: Frogs were injected intraperitoneally with bacteria, and the RNA of the brains (which have protective barriers against the bacteria used) was extracted. Part of the RNA was bacterial RNA apparently resulting from the transcription of DNA transferred from bacteria to the brain cells.

Book ChapterDOI
01 Jan 1972
TL;DR: The basal hypothalamus serves as a primary control region for a multitude of visceral regulatory mechanisms essential for the organism, such as the regulation of temperature, feeding behavior, cardiovascular function, and many forms of emotion.
Abstract: The basal hypothalamus serves as a primary control region for a multitude of visceral regulatory mechanisms essential for the organism, such as the regulation of temperature (Hammel, 1968), feeding behavior (Stevenson, 1969), cardiovascular function (Zanchetti, 1970), and many forms of emotion (Kaada, 1967). In addition, as a consequence of its intimate relationship with the pituitary, and of the arrangement of the vascular system in the infundibular region, the tuberal hypothalamus has the unique role of being a neuroendocrine organ; this field has been reviewed extensively (McCann et al., 1968; Beyer and Sawyer, 1969; Martini et al., 1970).


Journal ArticleDOI
TL;DR: The fossil anomuran coprolite form-genera are defined by the type of the cross section of the longitudinal canals which pierce the fecal pellet.
Abstract: The fossil anomuran coprolite form-genera are defined by the type of the cross section of the longitudinal canals which pierce the fecal pellet. Arrangement and number of longitudinal canals within the 2 bilaterally symmetric groups of canals are the principal elements for the definition of form-species of anomuran coprolites. To-date the 4 thalassinid form-generaFavreina Bronnimann, 1955,Palaxius Bronnimann & Norton, 1960,Helicerina Bronnimann & Masse, 1968, andParafavreina Bronnimann, Caron & Zaninetti, 1972, and the single galatheid form-genusThoronetia Bronnimann, Caron & Zaninetti, 1972, have been established.

Journal ArticleDOI
TL;DR: In this paper, thermal and photochemical interconversions of isomeric diketones by skeletal rearrangements have been established to the extent summarized in schemes 2 and 3, and the intramolecular cycloaddition was found to be reversible photochemically.
Abstract: In continuation of previous work on cyclopentadienone dimers [3], thermal and photochemical interconversions of the isomeric diketones 1, 3, and 5 by skeletal rearrangements have been established to the extent summarized in schemes 2 and 3, and the intramolecular [2+2] cycloaddition 1 2 was found to be reversible photochemically.

Journal ArticleDOI
TL;DR: It is proposed that the afterpotential is due to the extension into the dark period of the same light-initiated process as is responsible for the plateau of the receptor potential.