Biomedical subjects

C Schindler

Publications and source records attributed to C Schindler.

At least 109 records · Page 6Linked to original sources

PubMed1995

Effects of lactate on glucose metabolism in healthy subjects and in severely injured hyperglycemic patients.

Hepatic glucose production is autoregulated during infusion of gluconeogenic precursors. In hyperglycemic patients with multiple trauma, hepatic glucose production and gluconeogenesis are increased, suggesting that autoregulation of hepatic glucose production may be defective. To better understand the mechanisms of autoregulation and its possible alterations in metabolic stress, lactate was coinfused with glucose in healthy volunteers and in hyperglycemic patients with multiple trauma or critical illness. In healthy volunteers, infusion of glucose alone nearly abolished endogenous glucose production. Lactate increased gluconeogenesis (as indicated by a decrease in net carbohydrate oxidation with no change in total [13C]carbohydrate oxidation) but did not increase endogenous glucose production. In patients with metabolic stress, endogenous glucose production was not suppressed by exogenous glucose, but lactate did not further increase hepatic glucose production. It is concluded that 1) in healthy humans, autoregulation of hepatic glucose production during infusion of lactate is still present when glycogenolysis is suppressed by exogenous glucose and 2) autoregulation of hepatic glucose production is not abolished in hyperglycemic patients with metabolic stress.

Adolescent↗

PubMed1995

Prevalence of atopy and pollinosis in the adult population of Switzerland (SAPALDIA study). Swiss Study on Air Pollution and Lung Diseases in Adults.

The Swiss SAPALDIA study is a large multicenter cross-sectional study initiated in 1991 to evaluate the relationship between environment and respiratory symptoms and diseases in adults, and included subjects from eight areas in Switzerland with distinctive environmental characteristics. We present here prevalence data for atopy, pollinosis and atopic asthma obtained from a random sample of 8,357 adults (18-60 years) assessed by standardized computer-based interview as well as by allergy skin prick tests (SPTs) (performed with Phazet) to grass, birch and Parietaria pollen, house dust mite, cat and dog epithelia and the moulds Alternaria and Cladosporium and by an in vitro allergy screen test (Phadiatop CAP FEIA system). On the basis of a positive Phadiatop (total 28.9%; males 32.9%, females 25.0%; p < 0.001) and/or a positive SPT (total 23%; males 25.0%, females 20.8%; p < 0.001), 32.3% of the study population were considered atopic (males 35.7%, females 28.8%; p < 0.001). Concerning the prevalence of skin sensitization (SPT wheal > or = 3 mm), the highest rate was observed for grass (12.7%), followed by house dust mite (8.9%), silver birch (7.9%), cat (3.8%) and dog (2.8%), whereas moulds and Parietaria elicited less than 1% positive SPTs. The prevalence of atopic rhinitis (rhinitis symptoms associated with atopy) was 13.5% (males 14.3%, females 12.6%; p < 0.05) and the prevalence of current hay fever varied between 9.1% (questionnaire answer and a positive SPT to at least one pollen), 11.2% (questionnaire answer and presence of atopy) to 14.2% (questionnaire answer only) with no significant difference by sex.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1995

Variability of FVC and FEV1 due to technician, team, device and subject in an eight centre study: three quality control studies in SAPALDIA. Swiss Study on Air Pollution and Lung Disease in Adults.

Lung function testing of a random population sample in the eight SAPALDIA (Swiss study on air pollution and lung diseases in adults) centres had to be performed simultaneously, within one year, by eight teams and 23 technicians. We conducted quality control studies to test for technician, team and device related systematic measurement errors. To assess technician effects, each centre conducted a study involving 12-19 subjects. Two studies with 13 participants each addressed team and device effects. In all studies, volunteers repeatedly performed spirometry with different technicians or devices. Effects due to technician, team or device were estimated (analysis of variance). Neither "technician" within any of eight teams nor "team" accounted for significant differences of forced vital capacity (FVC) or forced expiratory volume in one second (FEV1). The Device Effect Study revealed 10% lower FVC values for device No. 1 due to a technical problem occurring during the test day but not in the main SAPALDIA study. Further investigations revealed potential hardware and software sources of error which are not recognizable by trained technicians. These studies gave no evidence for systematic errors due to technician, team or device during the main SAPALDIA study. However, they revealed potential sources of error in modern devices, which function as "black boxes". Manufacturers should improve spirometry software to further enhance the technicians' attempts at accurate assessment.

Adult↗

PubMed1995

Cytokine signal transduction.

The normal growth, maturation, and activation of cells in most tissues requires stimulation with a defined set of growth factors. These growth factors bind cognate receptors on surface of target cells, and stimulate specific intracellular signals. Many of these signals culminate in the induction of a ligand-specific set of genes. The characterization of signaling components that mediate the induction of genes in response to IFNs has led to the identification of a new signal transduction pathway. The components of this pathway are able to rapidly transduce high fidelity signals directly from the receptor to the nucleus. Recently, many other cytokines and growth factors, including IFN-alpha, IFN-gamma, IL-6, and prolactin (PRL), have been shown to induce new genes through the same signaling paradigm.

Animals↗

PubMed1995

[Detection of Mycobacterium tuberculosis complex with polymerase chain reaction (PCR)].

248 respiratory specimens were examined using by Nested-PCR and by conventional methods (solid and liquid media). 54 specimens were culture-positive for M. tuberculosis, 51 of these were detected by PCR and conventional methods, whereas 3 were missed by PCR and 15 were only positive by PCR. 12 of the 15 culture-negative specimens derived from patients under treatment for tuberculosis. The 3 specimens, which are PCR negative could also be detected after modification of the method. The very high sensitivity depends on the high positive rate (21.8%) of the investigated specimens, so it is necessary to look also for other than pulmonary specimens, but it seems that his Nested-PCR is a highly specific and sensitive method for detecting of M. tuberculosis.

Bronchoalveolar Lavage Fluid↗

PubMed1994

Growth hormone specifically regulates serine protease inhibitor gene transcription via gamma-activated sequence-like DNA elements.

Growth hormone activates gene transcription of the serine protease inhibitors (SPI) 2.1 and 2.2 by an unknown mechanism. In order to define the promoter regions responsible for this effect and to characterize the transcription factors involved, we have performed gel electrophoresis mobility shift assays on nuclear extracts from cell lines transfected with growth hormone receptor cDNA. We have identified a 9-base pair DNA element, the SPI-GLE 1, which forms a complex with nuclear proteins following activation by growth hormone and which, when placed upstream of a minimal thymidine kinase promoter, drives chloramphenicol acetyltransferase expression in a growth hormone-dependent fashion. This element is similar to those from several genes regulated by other cytokines including interferon. The growth hormone-induced complexes formed were dependent on tyrosine phosphorylation but did not contain the interferon-gamma-activated transcription factor Stat 91. Competition studies with oligonucleotides similar to the SPI-GLE 1 reveal the sequence of a consensus element that specifically binds growth hormone-regulated nuclear proteins.

Animals↗

PubMed1994

IL-10-induced factors belonging to the p91 family of proteins bind to IFN-gamma-responsive promoter elements.

Expression of the gene encoding the high affinity IgG receptor (Fc gamma RI) is stimulated by IFN-gamma through a promoter element designated gamma-IFN activation site (GAS). This sequence binds a transcription factor designated gamma-IFN activation factor (GAF). GAF-GAS complexes contain an IFN-regulated 91-kDa protein (p91). In mouse peritoneal macrophages, IL-4 and IL-10 influenced both basal and IFN-gamma-induced expression of Fc gamma RI in opposite ways: IL-10 was stimulatory and IL-4 repressed Fc gamma RI expression. IL-4 or IL-10 did not affect the activation of GAF by IFN-gamma, but both activated the binding of latent, receptor-activated factors (RAFTs) to the Fc gamma RI GAS. RAFTs-IL-4 and -IL-10 migrated similarly in electrophoretic mobility shift assays but could be distinguished through their specificities for different GAS sequences and their reactivity with anti-p91 antisera. These experiments also revealed two distinct RAFTs-IL-10 to be members of the p91 family of proteins. The data suggest GAS-related elements to integrate signals from IFN-gamma-, IL-4- and IL-10-activated signaling paths.

Animals↗

PubMed1994

Transcription factor ISGF-3 formation requires phosphorylated Stat91 protein, but Stat113 protein is phosphorylated independently of Stat91 protein.

Transcription factor ISGF-3 is a multiprotein, interferon alpha-activated transcription complex consisting of a 48-kDa DNA-binding protein and two proteins termed Stats (for signal transducers and activators of transcription) that become phosphorylated on tyrosine in the cell cytoplasm, a 113-kDa and either a 91- or 84-kDa polypeptide, the latter two of which arise from differentially spliced mRNAs. Using cell lines lacking the Stat91 or Stat84 proteins, we show that mutations in several different sites in the 91-kDa protein block the interferon alpha-induced phosphorylation of the 91-kDa protein and subsequent ISGF-3 formation. Although correct tyrosine phosphorylation on residue 690 of the Stat113 protein occurs independent of the Stat91/84 protein, the Stat113 phosphoprotein by itself moves to the cell nucleus much less efficiently in the absence of phosphorylated Stat91/84 protein.

Amino Acid Sequence↗

PubMed1994

A novel interferon-alpha-regulated, DNA-binding protein participates in the regulation of the IFP53/tryptophanyl-tRNA synthetase gene.

We have investigated the transcriptional response of the IFP53/tryptophanyl-tRNA synthetase gene to interferon-alpha (IFN-alpha). A single gamma-interferon activation site (GAS) in proximity to the transcription start sites was found to mediate the response of the IFP53 gene to IFN-alpha. This DNA element bound two distinct protein factors, alpha-interferon activation factor 1 (AAF1) and AAF2, which were rapidly activated in the cytoplasm of IFN-alpha-treated HeLa cells. AAF1, like the gamma-interferon activation factor, bound to the GAS from different IFN-responsive promoters and contained the 91-kDa ISGF3 protein (p91). However, in complexes with the IFP53 or Ly6A/E GAS, p91 was the only ISGF3 protein, whereas in the case of the GBP GAS, the 48-kDa protein (p48) was also present. AAF2 was found to preferentially bind to the IFP53 GAS, but not at all to the GBP GAS, and contained no ISGF3 protein. Therefore, GAS-binding regulatory factors in the IFN-alpha response can either consist of proteins found in ISGF3 or be formed by distinct proteins that are similarly linked to IFN-alpha-induced signal transduction.

Blotting, Western↗

PubMed1994

STF-IL-4: a novel IL-4-induced signal transducing factor.

The mechanism by which interleukin-4 (IL-4) regulates the expression of particular genes is unknown. We have determined that IL-4 induces a DNA binding factor (termed STF-IL-4) which has a strong affinity for an IFN-gamma activation site (GAS). Interestingly, STF-IL-4 also binds to the IL-4 responsive promoter for the Ig heavy chain germline epsilon transcript. The IL-4 dependent activation of STF-IL-4 is rapid, does not require protein synthesis and results in the sequential appearance of binding activity first in the cytoplasm and then later in the nucleus. Activation of STF-IL-4 is sensitive to tyrosine kinase inhibitors and the active factor is tyrosine phosphorylated. This pattern of activation is similar to the activation of interferon-induced transcription factors. STF-IL-4 appears to be a new member of a growing family of cytokine-induced transcriptional regulators.

Animals↗

PubMed1994

Association of transcription factor APRF and protein kinase Jak1 with the interleukin-6 signal transducer gp130.

Interleukin-6 (IL-6), leukemia inhibitory factor, oncostatin M, interleukin-11, and ciliary neurotrophic factor bind to receptor complexes that share the signal transducer gp130. Upon binding, the ligands rapidly activate DNA binding of acute-phase response factor (APRF), a protein antigenically related to the p91 subunit of the interferon-stimulated gene factor-3 alpha (ISGF-3 alpha). These cytokines caused tyrosine phosphorylation of APRF and ISGF-3 alpha p91. Protein kinases of the Jak family were also rapidly tyrosine phosphorylated, and both APRF and Jak1 associated with gp130. These data indicate that Jak family protein kinases may participate in IL-6 signaling and that APRF may be activated in a complex with gp130.

Antigens, CD↗

PubMed1994

Tyrosine phosphorylated p91 binds to a single element in the ISGF2/IRF-1 promoter to mediate induction by IFN alpha and IFN gamma, and is likely to autoregulate the p91 gene.

ISGF2 was initially identified, purified and cloned as an interferon-alpha (IFN alpha) induced transcription factor that binds to the IFN-stimulated response element (ISRE) of IFN alpha/beta-stimulated genes (ISGs). It was reported to be transcriptionally regulated by several cytokines including IFN alpha and IFN gamma. IFN alpha and IFN gamma inducibility is mediated by a single element: a high affinity, nearly palindromic version of the IFN gamma activation site (GAS). The ISGF2 GAS is bound specifically by p91, which was previously identified as a subunit of the ISG activator ISGF3, and shown to mediate IFN gamma induction of the GBP gene via a GAS. Tyrosine phosphorylation and DNA binding activity of p91 parallel transcription of ISGF2 in response to IFN alpha and/or IFN gamma, consistent with induction mediated by only a GAS. Transcription of the genes that encode p91 and p113, another subunit of ISGF3, is activated only by IFN alpha. This result suggests induction mediated by an ISRE, and implies autoregulation, requiring the products of both genes. Specificity of the ISRE is the basis for the previous conclusion. In contrast, it appears likely that the ISGF2 GAS, and p91 or related factors, also mediate induction of ISGF2 by IL-6 and prolactin. Convergence of signalling pathways from at least four cytokines on this single site would thus be a key aspect of a general role for ISGF2 in cellular growth control.

Alternative Splicing↗

PubMed1994

Proenkephalin transgenic mice: a short promoter confers high testis expression and reduced fertility.

The regulation and possible function of the preproenkephalin gene in testis were studied in vivo in transgenic mice containing: (1) bases -193 to +210 of the human proenkephalin gene and an additional one kilobase of 3' proenkephalin flanking sequence driving expression of bacterial chloramphenicol acetyltransferase (CAT), and (2) the same promoter and flanking sequences driving expression of a rat proenkephalin cDNA. Five lines of mice, designated HEC1-5, expressed the first construct and 10, HER1-10, the second. Each HEC male and many HER males showed dramatic expression of the transgene in the testis, although much lower expression was observed in the brain and other enkephalin-producing tissues. High levels of expression in testis can thus be achieved with a very short promoter region and do not require intron A sequences previously considered necessary. Altered enkephalin expression may affect testicular function. One founder, HER8, displayed grossly abnormal testicular morphology and was completely infertile. A second founder, HER6, had low sperm motility. Two offspring from other lines also displayed subnormal fertility. These studies support a role for specific promoter sequences in testis expression and may further support a significant role for proenkephalin in testicular function.

Animals↗

PubMed1994

A factor induced by differentiation signals in cells of the macrophage lineage binds to the gamma interferon activation site.

Rapid transcriptional induction of genes in response to gamma interferon (IFN-gamma) is mediated by the IFN-gamma activation site (GAS) and its cognate protein, the IFN-gamma activation factor (GAF). We describe a GAS-associated, differentiation-induced factor (DIF) as a potential molecular link between the activities of IFN-gamma and of growth and differentiation factors. DIF DNA binding was activated by colony-stimulating factor 1 in murine macrophages and also during tetradecanoyl phorbol acetate-induced differentiation or IFN-gamma treatment in myeloid U937 cells. IFN-gamma activation of DIF decreased significantly upon monocytic differentiation. DIF binding to DNA was inhibited by antiphosphotyrosine antibodies and could be induced by treatment of U937 cells with vanadate. Unlike GAF, DIF-DNA complexes did not contain the 91-kDa protein (p91) from ISGF-3. DIF bound with high affinity to GAS from the promoters of the IFP 53/tryptophanyl-tRNA synthetase and Fc gamma RI genes, intermediate affinity to the Ly6A/E GAS, and low affinity to the guanylate-binding protein GAS. DIF may belong to a family of cytokine- or growth factor-induced factors binding with variable affinities to GAS-related elements: the interleukin-6-responsive acute-phase response factor associated with GAS from different IFN-inducible promoters but with a different preference of binding compared with DIF. The sis-inducible element of the c-fos promoter bound GAF but not DIF. However, the sis-inducible element could be changed by point mutation to compete for GAF and DIF binding. Our data show DIF to be a novel DNA-binding protein which is activated in response to differentiating signals. Moreover, they suggest that a family of cytokine- or growth factor-regulated proteins integrates and coordinates the responses to cytokines and to growth and differentiation factors by binding to GAS-related elements.

Animals↗

PubMed1994

The signalling pathways of interleukin-6 and gamma interferon converge by the activation of different transcription factors which bind to common responsive DNA elements.

Interleukin-6 (IL-6) and gamma interferon (IFN-gamma) induce a partially overlapping set of genes, including the genes for interferon regulatory factor 1 (IRF-1), intercellular adhesion molecule 1 (ICAM-1), and the acute-phase protein alpha 2-macroglobulin. We report here that the rat alpha 2-macroglobulin promoter is activated by IFN-gamma in human hepatoma (HepG2) cells and that the IFN-gamma response element maps to the same site previously defined as the acute-phase response element (APRE), which binds the IL-6-activated transcription factor APRF (acute-phase response factor). As was reported for fibroblasts, the IFN-gamma-regulated transcription factor GAF is phosphorylated at tyrosine after IFN-gamma treatment of HepG2 cells. IFN-gamma posttranslationally activates a protein which specifically binds to the alpha 2-macroglobulin APRE. This protein is shown to be identical or closely related to GAF. Although APRF and GAF are shown to represent different proteins, their binding sequence specificities are very similar. APRF and GAF bind equally well to the APRE sequences of various acute-phase protein genes as well as to the IFN-gamma response elements of the IRF-1, ICAM-1, and other IFN-gamma-inducible genes. Transient transfection analysis revealed that the IFN-gamma response elements of the IRF-1 and ICAM-1 promoters are able to confer responsiveness to both IFN-gamma and IL-6 onto a heterologous promoter. Therefore, APRF and GAF are likely to be involved in the transcriptional induction of these immediate-early genes by IL-6 and IFN-gamma, respectively. Taken together, these results demonstrate that two functionally distinct hormones, IL-6 and IFN-gamma, act through common regulatory elements to which different transcription factors sharing almost the same sequence specificity bind.

Alkaloids↗

PubMed1994

Mutant cell lines unresponsive to alpha/beta and gamma interferon are defective in tyrosine phosphorylation of ISGF-3 alpha components.

The 84-, 91-, and 113-kDa proteins of the ISGF-3 alpha complex are phosphorylated on tyrosine residues upon alpha interferon (IFN-alpha) treatment and subsequently translocate to the nucleus together with a 48-kDa subunit. In this study, we investigated the presence and the functional status of ISGF-3 alpha subunits and Tyk-2 and JAK1 tyrosine kinases in mutant HeLa cells defective in the IFN-alpha/beta and -gamma response. Stable cell fusion analysis revealed a single complementation group among one class (class B) of mutants. The class B mutants contain detectable level of mRNA and proteins of the 84-, 91-, and 113-kDa proteins, but neither the protein nor mRNA is inducible by IFN-alpha or -gamma. The 91-kDa protein IFN-gamma-activated factor fails to be activated into a DNA-binding state after IFN-alpha or -gamma treatment. In addition, the 91-kDa protein is unable to localize in the nucleus after IFN-alpha and -gamma treatment, and the 113-kDa protein fails to translocate after IFN-alpha treatment. Immunoprecipitation studies document a failure of phosphorylation of the 84- or 91-kDa proteins after IFN-alpha or -gamma treatment. Similarly, no tyrosine-phosphorylated 113-kDa protein was detected after IFN-alpha treatment. The inability of class B mutants to phosphorylate the 84-, 91-, or 113-kDa protein on tyrosine residues correlated with the loss of biological response to IFN-alpha and -gamma. The genetic defect appears to be the absence of the tyrosine kinase JAK1. Our data therefore confirm a recent report that JAK1 plays a critical early signaling role for both IFN-alpha/beta and IFN-gamma systems.

Blotting, Western↗

PubMed1994

The interleukin-6-activated acute-phase response factor is antigenically and functionally related to members of the signal transducer and activator of transcription (STAT) family.

Interleukin-6 (IL-6), leukemia inhibitory factor, oncostatin M, IL-11, and ciliary neurotropic factor are a family of cytokines and neuronal differentiation factors which bind to composite plasma membrane receptors sharing the signal transducing subunit gp130. We have shown recently that IL-6 and leukemia inhibitory factor rapidly activate a latent cytoplasmic transcription factor, acute-phase response factor (APRF), by tyrosine phosphorylation, which then binds to IL-6 response elements of various IL-6 target genes. Here we demonstrate that APRF is activated by all cytokines acting through gp130 and is detected in a wide variety of cell types, indicating a central role of this transcription factor in gp130-mediated signaling. APRF activation is also observed in vitro upon addition of IL-6 to cell homogenates. Protein tyrosine kinase inhibitors block both the tyrosine phosphorylation and DNA binding of APRF. The factor was purified to homogeneity from rat liver and shown to consist of a single 87-kDa polypeptide, while two forms (89 and 87 kDa) are isolated from human hepatoma cells. As reported earlier, the binding sequence specificity of APRF is shared by gamma interferon (IFN-gamma) activation factor, which is formed by the Stat91 protein. Partial amino acid sequence obtained from purified rat APRF demonstrated that it is likely to be related to Stat91. In fact, an antiserum raised against the amino-terminal portion of Stat91 cross-reacted with APRF, suggesting the relatedness of APRF and Stat91. Altogether, these data indicate that APRF belongs to a growing family of Stat-related proteins and that IFN-gamma and IL-6 use similar signaling pathways to activate IFN-gamma activation factor and APRF, respectively.

3T3 Cells↗

PubMed1994

Replication-incompetent adenoviruses as vectors for protective immunization against measles virus infection.

Despite the availability of an efficient live-attenuated measles virus vaccine about 1.5 million annual deaths from measles infections and their complications are recorded worldwide. Particularly in developing countries measles remains an unsolved problem and a new vaccine seems necessary. In our animal model of measles virus infection in rats we studied a candidate vaccine based on infectious replication incompetent (E1A-) adenovirus (RAd) where measles virus genes are expressed under the control of the cytomegalovirus immediate early promoter. The aim of the study was to characterize the cell mediated and humoral immunity after immunization with RAd and its protective effect. After challenge with a lethal dose of measles virus no signs of disease or histopathological changes were detected in RAd68-immunized rats. The elimination of measles virus was successful within a few days. The results demonstrate that defective recombinant adenovirus vectors can induce complete protection from experimental measles infection in rats.

Adenoviridae↗