Showing papers by "University of Geneva published in 1989"
TL;DR: It is proposed that TNF released from macrophages in the microenvironment of developing granulomas is involved in a process of autoamplification: acting in an autocrine or paracrine way, it enhances its own synthesis and release, thus favoring further macrophage accumulation and differentiation leading to bacterial elimination.
1,241 citations
TL;DR: The level of tumor necrosis factor is frequently increased in patients with severe falciparum malaria, particularly in those with cerebral malaria or hypoglycemia, and whether it is important in the pathogenesis of the signs and symptoms of the disease requires further study.
Abstract: To investigate the role of tumor necrosis factor in Plasmodium falciparum infections, we measured serum concentrations of this cytokine in 65 Malawian children with severe falciparum malaria. Of these children (mean age, 5.3 years), 55 were unconscious and 10 had hypoglycemia at presentation. Although there was considerable overlap, the mean (±SEM) initial serum concentration of tumor necrosis factor was significantly higher in the 10 patients who died (709±312 pg per milliliter) than in the 55 who survived (184±32 pg per milliliter; P<0.02). The mortality rate increased with the concentration of tumor necrosis factor: at a level of less than 100 pg per milliliter, 1 of 24 patients died; at 100 to 500 pg per milliliter, 6 of 34 patients; and at more than 500 pg per milliliter, 3 of 7 patients. High concentrations of tumor necrosis factor were also associated with hypoglycemia (P<0.02), hyperparasitemia (P<0.002), age under three years (P<0.03), and severity of illness as measured by a prognostic ...
845 citations
TL;DR: About one third of patients with various malignant diseases were found to have extractable amounts of DNA in their plasma whereas no DNA could be detected in normal controls.
Abstract: About one third of patients with various malignant diseases were found to have extractable amounts of DNA in their plasma whereas no DNA could be detected in normal controls. Using the test establishe
678 citations
TL;DR: Results indicate that in response to bleomycin, the T lymphocytes induce an increase of the pulmonary TNF production, which leads to alveolar damage, growth of fibroblast, and collagen deposition, which is almost completely prevented by anti-TNF antibody.
Abstract: The role of TNF-alpha/cachectin in the pneumopathy elicited by bleomycin has been investigated. After a single intratracheal bleomycin instillation, an increase of the lung TNF-alpha mRNA level was evident, from days 5 to 15, as shown by Northern gel analysis of whole lung RNA. In contrast, lung IL-1-alpha and GM-CSF mRNA were not detectable. In mice passively immunized with rabbit anti-mouse TNF-alpha IgG, the bleomycin-induced collagen deposition, evaluated by the total lung hydroxyproline assay on day 15, was prevented. Depletion of the CD4 and CD8 T lymphocytes by an in vivo treatment with mAb prevented the bleomycin-induced increase of TNF mRNA level and fibrosis. After an administration of bleomycin in continuous intraperitoneal perfusion, the diffuse alveolar damage observed by light and electron microscopy was almost completely prevented by anti-TNF antibody. These results indicate that in response to bleomycin, the T lymphocytes induce, by an undefined mechanism, an increase of the pulmonary TNF production, which leads to alveolar damage, growth of fibroblast, and collagen deposition.
592 citations
Journal Article•
TL;DR: The findings suggest that contrary to myofibroblasts of normally healing granulation tissue and normally healed scars, my ofibro Blasts of pathologic conditions characterized by chronic retraction express always immunochemical features indicative of smooth muscle differentiation.
485 citations
TL;DR: It is shown that a larger signature comprising this sequence is common to most of the known zinc‐dependent endopeptidases, and that the presence of the signature can be indicative of membership in the family.
438 citations
TL;DR: Using a particle gun, a reliable nuclear transformation system has been established by complementing three mutants deficient in ASL activity with the wild‐type ASL gene and analysis of the transformants reveals variable patterns of integration of the transforming DNA into the nuclear genome.
Abstract: The argininosuccinate lyase (ASL) gene of Chlamydomonas reinhardtii has been cloned using four oligonucleotide probes corresponding to highly conserved regions of the ASL polypeptide sequence. The identity of the gene was confirmed by partial sequencing. It is unique, contains several introns and spans a region less than 7.8 kb that includes highly repetitive sequences. Using a particle gun, a reliable nuclear transformation system has been established by complementing three mutants deficient in ASL activity with the wild-type ASL gene. Analysis of the transformants reveals variable patterns of integration of the transforming DNA into the nuclear genome. Previous work has mapped the mutations in the mutants arg2 and arg7 to either end of the ARG7 locus 1.0 to 1.6 recombination map units apart. Our transformation results show that these two mutations are located within a region of 7.8 kb. This allows for the first correlation of the recombination map and the molecular map at the ARG7 locus and indicates a high recombination frequency in this region of the nuclear genome.
436 citations
TL;DR: Golgi-derived coated vesicles have a putative polypeptide composition that is distinct from both cytosol and Golgi membranes, as well as from that of clathrin-coated vesicle.
429 citations
TL;DR: In SMC and pericytes, alpha-sm actin was localized in microfilament bundles, strengthening the assumption that it is the functional isoform in these cell types and supporting the assumptions that each cell types exert contractile functions.
Abstract: alpha-Smooth muscle (alpha-sm) actin, an isoform typical of smooth muscle cells (SMC) and present in high amounts in vascular SMC, was demonstrated in the cytoplasm of pericytes of various rat and human organs by means of immunocytochemistry at the electron microscopic level. In SMC and pericytes, alpha-sm actin was localized in microfilament bundles, strengthening the assumption that it is the functional isoform in these cell types and supporting the assumption that pericytes exert contractile functions.
366 citations
TL;DR: Injections of neutralizing monoclonal antibody against recombinant murine interferon gamma, not later than 4 days after infection, markedly reduced the incidence of ECM and the elevation in serum levels of tumor necrosis factor.
Abstract: Experimental cerebral malaria (ECM), a lethal hyperacute neurological syndrome associated with high blood levels of tumor necrosis factor, develops in genetically susceptible (CBA/Ca) mice 7 days after infection with Plasmodium berghei ANKA strain. Injections of neutralizing monoclonal antibody against recombinant murine interferon gamma, not later than 4 days after infection, markedly reduced the incidence of ECM and the elevation in serum levels of tumor necrosis factor. This treatment prevented the cerebral lesions (plugging of brain vessels by monocytes, lymphocytes, and parasitized erythrocytes). In contrast, the extent of macrophage infiltration in lymphoid organs (which is a characteristic feature of mice developing ECM), as well as the course of infection, remained unaffected by the antibody treatment. Protected mice died at a later time of severe anemia and overwhelming parasitemia, the usual outcome of P. berghei infection in mice that are not susceptible to ECM. The present data indicate that interferon gamma constitutes an important link in the cytokine network that leads to brain vessel inflammation in experimental malaria. It is proposed that interferon gamma released by activated CD4+ T cells acts by augmenting both production and action of tumor necrosis factor.
314 citations
TL;DR: It is found that purified topoisomerase II preferentially binds and aggregates SAR‐containing DNA and this interaction is highly cooperative and, with increasing concentrations of topoisome II, the protein titrates quantitatively first SAR‐ containing DNA and then non‐SAR DNA.
Abstract: DNA elements termed scaffold-associated regions (SARs) are AT-rich stretches of several hundred base pairs which are known to bind specifically to nuclear or metaphase scaffolds and are proposed to specify the base of chromatin loops. SARs contain sequences homologous to the DNA topoisomerase II cleavage consensus and this enzyme is known to be the major structural component of the mitotic chromosome scaffold. We find that purified topoisomerase II preferentially binds and aggregates SAR-containing DNA. This interaction is highly cooperative and, with increasing concentrations of topoisomerase II, the protein titrates quantitatively first SAR-containing DNA and then non-SAR DNA. About one topoisomerase II dimer is bound per 200 bp of DNA. SARs exhibit a Circe effect; they promote in cis topoisomerase II-mediated double-strand cleavage in SAR-containing DNA fragments. The AT-rich SARs contain several oligo(dA).oligo(dT) tracts which determine their protein-binding specificity. Distamycin, which is known to interact highly selectively with runs of A.T base pairs, abolishes the specific interaction of SARs with topoisomerase II, and the homopolymer oligo(dA).oligo(dT) is, above a critical length of 240 bp, a highly specific artificial SAR. These results support the notion of an involvement of SARs and topoisomerase II in chromosome structure.
TL;DR: The mouse albumin gene promoter has six closely spaced binding sites for nuclear proteins that are located between the TATA motif and nucleotide position -170, where the HNF-1 and C/EBP binding sites strongly activate transcription in a tissue-specific manner.
Abstract: The mouse albumin gene promoter has six closely spaced binding sites for nuclear proteins that are located between the TATA motif and nucleotide position -170. In vitro transcription with liver or spleen nuclear extracts of templates containing either mutated or polymerized albumin promoter elements establishes a hierarchy of the different protein binding sites for tissue-specific albumin gene transcription. The HNF-1 and C/EBP binding sites strongly activate transcription in a tissue-specific manner. The NF-Y binding site has a lower activation potential and is less specific, being equally efficient in liver and spleen nuclear extracts. The remaining elements are relatively weak activator sites.
TL;DR: Observations establish the in vivo expression of the u- PA gene by invading and migrating trophoblast cells in a biphasic time pattern in agreement with the proposed involvement of the enzyme in the extracellular proteolysis accompanying embryo implantation.
Abstract: To assess in vivo the postulated participation of urokinase-type (u-PA) and tissue-type (t-PA) plasminogen activators in processes involving tissue remodeling and cell migration, we have studied the cellular distribution of u-PA and t-PA mRNAs during mouse oogenesis and embryo implantation. By in situ hybridizations, we detected t-PA mRNA in oocytes and u-PA mRNA in granulosa and thecal cells from preovulatory follicles. These findings are compatible with a role for plasminogen activators in oogenesis and follicular disruption. We demonstrated the presence of u-PA mRNA in the invasive and migrating trophoblast cells of 5.5- and 6.5-d-old embryos. At 7.5 days, u-PA mRNA was predominantly localized to trophoblast cells that had reached the deep layers of the uterine wall, while the peripheral trophoblast cells surrounding the presomite stage embryo were devoid of specific signal. In 8.5-d-old embryos abundant u-PA mRNA expression resumed transiently in the giant trophoblast cells at the periphery of the embryo and in the trophoblast cells of the ectoplacental cone, to become undetectable in 10.5-d-old embryos. These observations establish the in vivo expression of the u-PA gene by invading and migrating trophoblast cells in a biphasic time pattern; they are in agreement with the proposed involvement of the enzyme in the extracellular proteolysis accompanying embryo implantation.
TL;DR: The data are consistent with a metabolic model in which malonyl-CoA mediates the switch from fatty acid catabolism to lipid synthesis during glucose stimulation of beta-cells, and it is suggested that these changes in lipid metabolism could play a pivotal role in the regulation of the sustained phase of insulin secretion.
TL;DR: Evidence is presented here that tumor necrosis factor/cachectin (TNF), is of crucial importance in the pathogenesis of cerebral malaria and metabolic parameters of CM and its main lesion in both mouse and human, correspond to the known properties of TNF.
Abstract: Evidence is presented here that tumor necrosis factor/cachectin (TNF), is of crucial importance in the pathogenesis of cerebral malaria. First, the central lesion of CM, hemorrhagic necrosis of cerebral vessels, corresponds to lesions observed during other pathological conditions associated with high serum TNF levels, such as endotoxemic shock or administration of TNF. Second, in both mouse and human, there is a close correlation between high serum TNF levels and CM. At least in mouse, high TNF levels and CM depend upon T lymphocytes of the CD4+ phenotype. Third, passive immunization against mouse TNF significantly prolongs the survival of P. berghei-infected CBA/Ca mice, and prevents the development of neurologic signs. Treatment with the anti-TNF antibody also prevents hemorrhagic necrosis of brain vessels. Fourth, in the mouse model, a cytokine cascade including at least GM-CSF, IL-3 and IFN-gamma is required for the elevation of TNF level. This cascade appears to involve two components: (a) a quantitative component: increased accumulation of macrophages results from the concomitant release of IL-3 and GM-CSF, and (b) a qualitative component: macrophage number has not only to be raised, but macrophages need to be activated by IFN-gamma. Fifth, metabolic parameters of CM and its main lesion in both mouse and human, i.e. the hemorrhagic necrosis of small brain vessels, correspond to the known properties of TNF.
TL;DR: In this paper, a simple quantitative and realistic in situ method to test the bioadhesive potential of polymers was developed, in which the glass spheres or drug crystals were first coated with the polymers to be tested.
TL;DR: In this article, spontaneous symmetry breaking of global supersymmetry for a single scalar superfield in an arbitrary Kahler manifold is discussed, where the curvature of the manifold goes to infinity (or equivalently the masses of the scalar partners of the goldstino go to infinity).
TL;DR: UPA bound at the cell surface is tightly associated with an amphiphilic membrane protein, which is species-specific, since human uPA fails to bind to murine cells, and murine uPA does not bind to human cells.
TL;DR: This work takes advantage of a cell-free system that reconstitutes essentially a single round of transport of the VSV-encoded G protein between Golgi cisternae to identify discrete stages in the maturation of carrier vesicles to imply that a coated bud (pit)-coated vesicle-uncoatedVesicle system analogous to that responsible for receptor-mediated endocytosis carries biosynthetic protein transport across the Golgi stack.
TL;DR: Comparing the potencies of insulin, proinsulin, and insulin-like growth factor I in this system indicates that induction by insulin is mediated via the insulin receptor, and a cAMP-mediated repression mechanism is a key aspect in the regulation of glucokinase gene transcription in the hepatocyte.
TL;DR: A role for regulated polyadenylation is established in the post-transcriptional control of gene expression after meiotic maturation of mouse oocytes through translational activation of dormant tissue-type plasminogen activator mRNA and injected RNA fragments that correspond to part of the 3'-untranslated region (3'UTR) of this mRNA.
Abstract: The translational activation of dormant tissue-type plasminogen activator mRNA during meiotic maturation of mouse oocytes is accompanied by elongation of its 3'-poly(A) tract. Injected RNA fragments that correspond to part of the 3'-untranslated region (3'UTR) of this mRNA are also subject to regulated polyadenylation. Chimeric mRNAs containing part of this 3'UTR are polyadenylated and translated following resumption of meiosis. Polyadenylation and translation of chimeric mRNAs require both specific sequences in the 3'UTR and the canonical 3'-processing signal AAUAAA. Injection of 3'-blocked mRNAs and in vitro polyadenylated mRNAs shows that the presence of a long poly(A) tract is necessary and sufficient for translation. These results establish a role for regulated polyadenylation in the post-transcriptional control of gene expression.
TL;DR: The complete nucleotide sequence of nahC, the structural gene for 1,2-dihydroxynaphthalene dioxygenase encoded in the NAH7 plasmid of Pseudomonas putida is determined and it has been shown that intradiol enzymes evolved from a common ancestor.
TL;DR: Using in vitro transcription assays, it is demonstrated that purified HNF1 strongly stimulates albumin promoter activity in spleen nuclear extracts, which are devoid of this factor.
TL;DR: Results support a possible role for this glucose transporter in glucose sensing by beta cells and provide evidence that these cells are polarized.
Abstract: Immunocytochemical techniques revealed that the "liver-type" glucose transporter is present in the insulin-producing beta cells of rat pancreatic islets but not in other islet endocrine cells. Ultrastructural analysis of the transporter by the protein A-gold technique showed that it is restricted to certain domains of the plasma membrane, its density being sixfold higher in microvilli facing adjacent endocrine cells than in the flat regions of the plasma membrane. These results support a possible role for this glucose transporter in glucose sensing by beta cells and provide evidence that these cells are polarized.
TL;DR: Electron microscopy and biochemical studies show that fatty acyl-CoA is required for budding of (non-clathrin-) coated transport vesicles from Golgi cisternae and that budding is inhibited by the nonhydrolyzable analog.
TL;DR: Metallo-ene reactions, hardly recognized until very recently, have experienced a breathtaking development when applied in an intramolecular sense as mentioned in this paper and have served as a cornerstone for numerous syntheses of structurally diverse natural products (e.g., sesquiterpenes of marine or plant origin, alkaloids, fragrances, insect defense compounds, and a fungitoxin).
Abstract: Metallo-ene reactions, hardly recognized until very recently, have experienced a breathtaking development when applied in an intramolecular sense. Efficient regio- and stereoselective magnesium-ene cyclizations have served as a cornerstone for numerous syntheses of structurally diverse natural products (e.g., sesquiterpenes of marine or plant origin, alkaloids, fragrances, insect defense compounds, and a fungitoxin). A brilliant example is the synthesis of the elusive odorant (+)-khusimone which outshines 20 years of work in the field of tricyclovetivane synthesis. Palladium-, platinum-, and nickel-catalyzed versions of the metallo-ene reaction are in a comparatively early stage of exploration, but, nevertheless, reveal intriguing potential. Hence an almost 100% stereospecific CO→C;Pd-→ CC chirality transfer permits simple and selective, cis- or trans-annelation processes. The mild cyclization conditions are compatible with various functional groups, such as nitrogen moieties, which offer interesting perspectives for the preparation of heterocycles (e.g., alkaloids) difficult to obtain by other methods. Carbon monoxide insertion reactions of the cyclized σ-metal intermediates were shown to afford annelated cyclopentanones and cyclopentenones with concomitant stereocontrolled formation of four carbon–carbon bonds. These and other observations, highlighted in this article, provide a platform for further extensions and applications of this powerful method in organic synthesis.
TL;DR: It is concluded that alternative splicing and/or the use of distinct tissue-specific promoters generate structurally distinct mRNA species in liver and islets of Langerhans and that tissue- specific transcription mechanisms result in inducible expression of the glucokinase gene in liver but not in islets during the fasting-refeeding transition.
Abstract: Glucokinase, a key regulatory enzyme of glucose metabolism in mammals, provides an interesting model of tissue-specific gene expression. The single-copy gene is expressed principally in liver, where it gives rise to a 2.4-kilobase mRNA. The islets of Langerhans of the pancreas also contain glucokinase. Using a cDNA complementary to rat liver glucokinase mRNA, we show that normal pancreatic islets and tumoral islet cells contain a glucokinase mRNA species approximately 400 nucleotides longer than hepatic mRNA. Hybridization with synthetic oligonucleotides and primer-extension analysis show that the liver and islet glucokinase mRNAs differ in the 5' region. Glucokinase mRNA is absent from the livers of fasted rats and is strongly induced within hours by an oral glucose load. In contrast, islet glucokinase mRNA is expressed at a constant level during the fasting-refeeding cycle. The level of glucokinase protein in islets measured by immunoblotting is unaffected by fasting and refeeding, whereas a 3-fold increase in the amount of enzyme occurs in liver during the transition from fasting to refeeding. From these data, we conclude (i) that alternative splicing and/or the use of distinct tissue-specific promoters generate structurally distinct mRNA species in liver and islets of Langerhans and (ii) that tissue-specific transcription mechanisms result in inducible expression of the glucokinase gene in liver but not in islets during the fasting-refeeding transition.
TL;DR: The psbC gene of Chlamydomonas reinhardtii encodes P6, the 43 kd photosystem II core polypeptide, and two nuclear mutants, F34 and F64, and one chloroplast mutant, FuD34, are unable to synthesize P6.
Abstract: The psbC gene of Chlamydomonas reinhardtii encodes P6, the 43 kd photosystem II core polypeptide. The sequence of P6 is highly homologous to the corresponding protein in higher plants with the exception of the N-terminal region where the first 12 amino acids are missing. Translation of P6 is initiated at GUG in C. reinhardtii. The chloroplast mutant MA16 produces a highly unstable P6 protein. The mutation in this strain maps near the middle of the psbC gene and consists of a 6 bp duplication that creates a Ser-Leu repeat at the end of one transmembrane domain. Two nuclear mutants, F34 and F64, and one chloroplast mutant, FuD34, are unable to synthesize P6. All of these mutants accumulate wild-type levels of psbC mRNA. The FuD34 mutation has been localized near the middle of the 550 bp 5' untranslated region of psbC where the RNA can be folded into a stem-loop structure. A chloroplast suppressor of F34 has been isolated that partially restores synthesis of the 43 kd protein. The mutation of this suppressor is near that of FuD34, in the same stem-loop region. These chloroplast mutations appear to define the target site of a nuclear factor that is involved in P6 translation.
TL;DR: A comprehensive review of structure work on high-Tc oxides as reported during the years 1987 and 1988 is given in this paper, where 13 structures are refined from X-ray single-crystal and/or neutron powder diffraction data.
Abstract: A comprehensive review of structure work on high-Tc oxides as reported during the years 1987 and 1988 is given. Thirteen structures are refined from X-ray single-crystal and/or neutron powder diffraction data:I. (Ba1−x,Kx)BiO3 (Tc=30 K),II. (La2−x, Srx)CuO4 (Tc=40 K),III. (Nd, Ce, Sr)2CuO4 (Tc=28 K),IV. (Nd2−x, Cex)CuO4 (Tc=24 K),V. YBa2Cu3O7 (Tc=90 K),VI. YBa2Cu4O8 (Tc=80 K),VII. Y2Ba4Cu7O14 (Tc=40 K),VIII. Pb2Sr2NdCu3O8 (Tc=70 K),IX. TlBa2CaCu2O7 (Tc=103 K),X. TlBa2Ca2Cu3O9 (Tc=120 K),XI. Tl2Ba2CuO6 (Tc=90 K),XII. Tl2Ba2CaCu2O8 (Tc=112 K),XIII. Tl2Ba2Ca2Cu3O10 (Tc=125 K). Except forI (perovskite type),II (K2NiF4 type) andIV (Nd2CuO4 type) they represent new structure types. Structure data, bond distances, structure drawings and calculated X-ray powder diffraction patterns are given for each compound. Structural features and correlations with superconductivity are discussed. The review contains 301 citations.
TL;DR: It is shown here that the homologous contact between companion B-cells promotes the recruitment of secreting B- Cells and increases their individual secretion of insulin twofold over that of single B- cells.