Showing papers by "University of Zurich published in 1997"
TL;DR: Libraries of native folded proteins can now be screened and made to evolve in a cell-free system without any transformation or constraints imposed by the host cell.
Abstract: We report here a system with which a correctly folded complete protein and its encoding mRNA both remain attached to the ribosome and can be enriched for the ligand-binding properties of the native protein. We have selected a single-chain fragment (scFv) of an antibody 108-fold by five cycles of transcription, translation, antigen-affinity selection, and PCR. The selected scFv fragments all mutated in vitro by acquiring up to four unrelated amino acid exchanges over the five generations, but they remained fully compatible with antigen binding. Libraries of native folded proteins can now be screened and made to evolve in a cell-free system without any transformation or constraints imposed by the host cell.
1,329 citations
Book•
01 Mar 1997TL;DR: A survey of statistical and econometric techniques for the analysis of count data, with a focus on conditional distribution models, can be found in this paper, where the authors provide an up-to-date survey.
Abstract: The book provides graduate students and researchers with an up-to-date survey of statistical and econometric techniques for the analysis of count data, with a focus on conditional distribution models. Proper count data probability models allow for rich inferences, both with respect to the stochastic count process that generated the data, and with respect to predicting the distribution of outcomes. The book starts with a presentation of the benchmark Poisson regression model. Alternative models address unobserved heterogeneity, state dependence, selectivity, endogeneity, underreporting, and clustered sampling. Testing and estimation is discussed from frequentist and Bayesian perspectives. Finally, applications are reviewed in fields such as economics, marketing, sociology, demography, and health sciences.The fifth edition contains several new topics, including copula functions, Poisson regression for non-counts, additional semi-parametric methods, and discrete factor models. Other sections have been reorganized, rewritten, and extended.
977 citations
TL;DR: Three typical experiments are discussed that illustrate the potential of the slice-culture technique and indicate that, due to their high neuronal connectivity, slice cultures provide a very useful tool for studying the properties of synaptic transmission between monosynaptically coupled cell pairs.
913 citations
TL;DR: The microfluidic networks used to pattern biomolecules with high resolution on a variety of substrates suggest a practical way to incorporate biological material on technological substrates.
Abstract: Microfluidic networks (microFNs) were used to pattern biomolecules with high resolution on a variety of substrates (gold, glass, or polystyrene). Elastomeric microFNs localized chemical reactions between the biomolecules and the surface, requiring only microliters of reagent to cover square millimeter-sized areas. The networks were designed to ensure stability and filling of the microFN and allowed a homogeneous distribution and robust attachment of material to the substrate along the conduits in the microFN. Immunoglobulins patterned on substrates by means of microFNs remained strictly confined to areas enclosed by the network with submicron resolution and were viable for subsequent use in assays. The approach is simple and general enough to suggest a practical way to incorporate biological material on technological substrates.
818 citations
01 Jan 1997
TL;DR: Two-dimensional echocardiography will facilitate the diagnosis of IVNC in this subset of patients because of the high incidence of heart failure, ventricular arrhythmias, and embolization in adults with IVNC, early diagnosis is important.
Abstract: Objective To describe the entity of isolated ventricular noncompaction (IVNC) and present a series of cases of this rare disorder in an adult population. Material and Methods We review a 10-year experience with the diagnosis of IVNC and discuss the clinical, echocardiographic, and pathologic features of this condition. Echocardiographic diagnostic criteria included the absence of coexisting cardiac abnormalities, the presence of prominent and excessive trabeculations of one or more ventricular wall segments, and intertrabecular spaces perfused from the ventricular cavity. Pathologic examination focused on regions with exaggerated trabeculations and deep intertrabecular spaces. Results IVNC is an unexplained arrest of myo-cardial morphogenesis previously encountered mainly in pediatrie patients. Among 37,555 transthoracic echocardiographic studies performed at our hospital between January 1984 and October 1993, 17 cases of IVNC were identified in adult subjects (14 men and 3 women, 18 to 71 years of age). The mean time from onset of symptoms to correct diagnosis was 3.5 ± 5.7 years, and the mean duration of follow-up was 30 ± 28 months. Common clinical symptoms were heart failure, ventricular arrhythmias, and a history of embolie events. Two-dimensional echocardiog-raphy revealed 10 patients with left ventricular and 7 (41%) with biventricular IVNC. During a 6-year follow-up period, eight patients died and two underwent heart transplantation. Conclusion Although the diagnosis of IVNC in an adult population is often delayed because of similarities with more frequently diagnosed conditions, two-dimensional echocardiography will facilitate the diagnosis of IVNC in this subset of patients. Because of the high incidence of heart failure, ventricular arrhythmias, and embolization in adults with IVNC, early diagnosis is important.
741 citations
TL;DR: This review provides comprehensive information on the identification of c Coryneform bacteria and outlines recent changes in taxonomy and case reports claiming disease associations of coryneformacteria are critically reviewed.
Abstract: Coryneform bacteria are aerobically growing, asporogenous, non-partially-acid-fast, gram-positive rods of irregular morphology. Within the last few years, there has been a massive increase in the number of publications related to all aspects of their clinical microbiology. Clinical microbiologists are often confronted with making identifications within this heterogeneous group as well as with considerations of the clinical significance of such isolates. This review provides comprehensive information on the identification of coryneform bacteria and outlines recent changes in taxonomy. The following genera are covered: Corynebacterium, Turicella, Arthrobacter, Brevibacterium, Dermabacter. Propionibacterium, Rothia, Exiguobacterium, Oerskovia, Cellulomonas, Sanguibacter, Microbacterium, Aureobacterium, "Corynebacterium aquaticum," Arcanobacterium, and Actinomyces. Case reports claiming disease associations of coryneform bacteria are critically reviewed. Minimal microbiological requirements for publications on disease associations of coryneform bacteria are proposed.
740 citations
TL;DR: The authors argue that distrusting public laws risk destroying the positive attitude of citizens and politicians towards the state, and that a viable constitution must therefore be strict enough to deter exploitative behaviour.
Abstract: When discussing constitutional design, economists concentrate on the propensity of individuals to free ride. Preventing opportunistic behaviour by knaves has costs by crowding out civic virtue. Another view emphasises active citizen participation in order to bolster civic virtue. A viable constitution must therefore be strict enough to deter exploitative behaviour. At the same time, the constitution should fundamentally convey trust towards its citizens and politicians. Distrusting public laws risk destroying the positive attitude of citizens and politicians towards the state. Civic virtue can be maintained and fostered by direct citizen participation via popular referenda and initiatives.
718 citations
TL;DR: A monoclonal antibody is described, 15B3, that can discriminate between the normal and disease-specific forms of PrP, suggesting that it recognizes an epitope common to prions from different species.
Abstract: Prions are infectious particles causing transmissible spongiform encephalopathies (TSEs). They consist, at least in part, of an isoform (PrPSc) of the ubiquitous cellular prion protein (PrPC). Conformational differences between PrPC and PrPSc are evident from increased beta-sheet content and protease resistance in PrPSc. Here we describe a monoclonal antibody, 15B3, that can discriminate between the normal and disease-specific forms of PrP. Such an antibody has been long sought as it should be invaluable for characterizing the infectious particle as well as for diagnosis of TSEs such as bovine spongiform encephalopathy (BSE) or Creutzfeldt-Jakob disease (CJD) in humans. 15B3 specifically precipitates bovine, murine or human PrPSc, but not PrPC, suggesting that it recognizes an epitope common to prions from different species. Using immobilized synthetic peptides, we mapped three polypeptide segments in PrP as the 15B3 epitope. In the NMR structure of recombinant mouse PrP, segments 2 and 3 of the 15B3 epitope are near neighbours in space, and segment 1 is located in a different part of the molecule. We discuss models for the PrPSc-specific epitope that ensure close spatial proximity of all three 15B3 segments, either by intermolecular contacts in oligomeric forms of the prion protein or by intramolecular rearrangement.
626 citations
TL;DR: Several hybridomas whose genes could not be cloned in previous experimental setups, but were successfully obtained with the present system, expressed high amounts of aberrant heavy and light chain mRNAs, which were amplified by PCR and greatly exceeded the amount of binding antibody sequences.
606 citations
TL;DR: The complementary distributions of PV and CB appear to correlate with distinct lemniscal and spinothalamic somatosensory pathways and to cerebellar and pallidal motor territories, respectively.
Abstract: To improve anatomical definition and stereotactic precision of thalamic targets in neurosurgical treatments of chronic functional disorders, a new atlas of the human thalamus has been developed. This atlas is based on multiarchitectonic parcellation in sections parallel or perpendicular to the standard intercommissural reference plane. The calcium-binding proteins parvalbumin (PV), calbindin D-28K (CB), and calretinin (CR) were used as neurochemical markers to further characterize thalamic nuclei and delimit subterritories of functional significance for stereotactic explorations. Their overall distribution reveals a subcompartmentalization of thalamic nuclei into several groups. Predominant PV immunostaining characterizes primary somatosensory, visual and auditory nuclei, the ventral lateral posterior nucleus, reticular nucleus (R), and to a lesser degree also, lateral part of the centre median nucleus, and anterior, lateral, and inferior divisions of the pulvinar complex. In contrast, CB immunoreactivity is prevalent in medial thalamic nuclei (intralaminar and midline), the posterior complex, ventral posterior inferior nucleus, the ventral lateral anterior nucleus, ventral anterior, and ventral medial nuclei. The complementary distributions of PV and CB appear to correlate with distinct lemniscal and spinothalamic somatosensory pathways and to cerebellar and pallidal motor territories, respectively. Calretinin, while overlapping with CB in medial thalamic territories, is also expressed in R and limbic associated anterior group nuclei that contain little or no CB. Preliminary analysis indicates that interindividual nuclear variations cannot easily be taken into account by standardization procedures. Nevertheless, some corrections in antero-posterior coordinates in relation to different intercommissural distances are proposed.
580 citations
TL;DR: Submitted abstracts should clearly state the purpose, brief statement of procedure, results and conclusions, and include the name, full address and topic on all submissions.
Abstract: s should clearly state the purpose, brief statement of procedure, results and conclusions. Please include your name, full address and topic on all submissions. At least one author of each abstract should register for the conference. All accepted abstracts will be published as symposium proceedings. Additionally, commended abstracts may be published in a journal after they are expanded to a manuscript followed by extensive reviewing. The language of the conference will be English.
Journal Article•
TL;DR: A survey of the bH LH-PAS family as well as of the genes regulated by HIF-1, and a summary of the current knowledge on the oxygen-dependent activation of this fascinating transcription factor are presented.
Abstract: The hypoxia-inducible factor-1 (HIF-1) is a basic-helix-loop-helix (bHLH) heterodimeric transcription factor activated by reductions in oxygen concentration (hypoxia). Activated HIF-1 upregulates expression of genes involved in the adaptation of higher organisms to hypoxic conditions, caused by e.g. high altitude, anemia, wound healing or during development. Examples of these oxy-genes include erythropoietin, a hormone regulating erythropoiesis and hence the oxygen transport capacity, and vascular endothelial growth factor, a potent inducer of angiogenesis leading to increased blood capillary density. The HIF-1 heterodimer is composed of a HIF-1alpha and an ARNT subunit, both belonging to the explosively growing PAS subfamily of bHLH transcription factors. Closely related, but differentially expressed, factors have recently been cloned, at least one of which can also be activated by hypoxia. In this review, we present a survey of the bH LH-PAS family as well as of the genes regulated by HIF-1, and we summarize our current knowledge on the oxygen-dependent activation of this fascinating transcription factor.
TL;DR: The results demonstrate that distinct components below 1 Hz are also present in the human sleep electroencephalogram spectrum, in accordance with results from animal experiments.
TL;DR: In this paper, it was shown that the weakly asymmetric exclusion process converges to the Kardar-Parisi-Zhang equation with a random noise on the density current.
Abstract: We consider two strictly related models: a solid on solid interface growth model and the weakly asymmetric exclusion process, both on the one dimensional lattice. It has been proven that, in the diffusive scaling limit, the density field of the weakly asymmetric exclusion process evolves according to the Burgers equation and the fluctuation field converges to a generalized Ornstein-Uhlenbeck process. We analyze instead the density fluctuations beyond the hydrodynamical scale and prove that their limiting distribution solves the (non linear) Burgers equation with a random noise on the density current. For the solid on solid model, we prove that the fluctuation field of the interface profile, if suitably rescaled, converges to the Kardar–Parisi–Zhang equation. This provides a microscopic justification of the so called kinetic roughening, i.e. the non Gaussian fluctuations in some non-equilibrium processes. Our main tool is the Cole-Hopf transformation and its microscopic version. We also develop a mathematical theory for the macroscopic equations.
TL;DR: Experimental evidence is summarised to illustrate that induction of immune reactivity depends upon antigen reaching and being available in lymphoid organs in a dose‐ and time‐dependent manner and that antigen, impendent upon localisation, dose and time, seems to be the simplest regulator of immune responses.
Abstract: Summary: This review summarises experimental evidence to illustrate that induction of immune reactivity depends upon antigen reaching and being available in lymphoid organs in a dose- and time-dependent manner. If antigen reaches lymph organs in a localised staggered manner and with a concentration gradient, a response is induced in the draining lymph node. Antigen-presenting cells are of critical importance to transport antigen from the periphery to local organised lymphoid tissue. If antigen is all over the lymphoid system, then it deletes all specific cells in the thymus or induces them within a few days: because of their limited life-span they then die off, leaving the repertoire depleted of this specificity. If antigen does not reach lymphoid organs it is ignored by immune cells. Once a response is induced, activated but not resting T cells will reach antigen outside lymphoid organs, whereas activated B cells differentiate into plasma cells in an inducing environment, mostly in lymphoid tissue including bone marrow, but also in chronic lymphoid-like infiltrations in peripheral organs. In immunopathology (when the infectious agent is known) or in autoimmunity (when the triggering infectious agent is not known or not recognised) lymphoid tissue may become organised close to the antigen (e.g. in organ-specific autoimmune diseases) and may thereby maintain an autoantigen-driven disease-causing immune response for a long time, The notion that naive T cells get induced or silenced in the periphery may be questioned because induction can only occur in lymphoid organs providing anatomical structures where critical cell-cell interactions are properly guided and where, therefore, cells are likely to meet sufficiently frequently and in a critical milieu. Since overall immune reactivity critically depends upon the localisation of antigens in a dose- and time-dependent manner, it seems more likely - but this remains to be shown - that activated T cells may get exhausted in non-lymphoid peripheral tissues, whereas they are usually maintained in lymphoid organs. The critical role of antigen in regulating immune responses also has relevance for our understanding of immunological defence against epithelial and mesenchymal tumours, against many infectious diseases and for understanding autoimmunity and immunological memory. Collectively the data indicate that antigen, impendent upon localisation, dose and time, seems to be the simplest regulator of immune responses.
TL;DR: The results indicate that Pan is an essential component of the Wg transduction pathway and suggest that it acts directly to regulate gene transcription in response to Wg signalling.
Abstract: Members of the Wnt/Wingless (Wg) family of signalling proteins organize many aspects of animal development by regulating the expression of particular target genes in responding cells. Recent biochemical studies indicate that the vertebrate HMG-domain proteins Lef-1 and XTcf-3 can physically interact with beta-catenin, a homologue of Drosophila Armadillo (Arm), the most downstream component known in the Wnt signal transduction pathway. However, these studies do not address whether the endogenous Lef/Tcf family members are required in vivo to transduce Wnt signals. Using genetic methods in Drosophila, we define a new segment polarity gene, pangolin (pan), and show that its product is required in vivo for Wg signal transduction in embryos and in developing adult tissues. In addition, we show that pan encodes a Lef/Tcf homologue and provide evidence that its protein product binds to the beta-catenin homologue Armadillo in vivo. Finally, we demonstrate that Pan functions downstream of Arm to transduce the Wg signal. Thus, our results indicate that Pan is an essential component of the Wg transduction pathway and suggest that it acts directly to regulate gene transcription in response to Wg signalling.
TL;DR: Risk factors for cardiovascular disease, such as hypertension, hypercholesterolemia, diabetes, vascular aging, and estrogen deficiency, are discussed in terms of their contributions to endothelial dysfunction, which may be the initial step in atherogenesis.
Abstract: The endothelium releases factors that control vascular relaxation and contraction, thrombogenesis and fibrinolysis, and platelet activation and inhibition. Maintaining the functional integrity of the endothelium, therefore, is critical for the preservation of blood flow and the prevention of thrombosis. This article reviews the primary endothelium-dependent substances that promote either relaxation (e.g., nitric oxide, prostacyclin) or contraction (e.g., endothelin) of blood vessels, including their physiology, mechanism of effect, and role in endothelial dysfunction. Risk factors for cardiovascular disease, such as hypertension, hypercholesterolemia, diabetes, vascular aging, and estrogen deficiency, are discussed in terms of their contributions to endothelial dysfunction, which may be the initial step in atherogenesis.
TL;DR: It is found that scrapie developed after peripheral inoculation in mice expressing immunoglobulins that were exclusively of the M subclass and without detectable specificity for the normal form of thePrPc, and in mice which had differentiated B cells but no functional follicular dendritic cells.
Abstract: Although prion proteins are most efficiently propagated through intracerebral inoculation, peripheral administration has caused the diseases kuru, iatrogenic Creutzfeldt-Jakob disease (CJD), bovine spongiform encephalopathy (BSE) and new-variant CJD. The development of neurological disease after peripheral inoculation depends on prion expansion within cells of the lymphoreticular system. Here we investigate the identity of these cells by using a panel of immune-deficient mice inoculated with prions intraperitoneally: we found that defects affecting only T lymphocytes had no apparent effect, but that all mutations that disrupted the differentiation and response of B lymphocytes prevented the development of clinical scrapie. As an absence of B cells and of antibodies correlates with severe defects in follicular dendritic cells, a lack of any of these three components may prevent the development of clinical scrapie. However, we found that scrapie developed after peripheral inoculation in mice expressing immunoglobulins that were exclusively of the M subclass and without detectable specificity for the normal form of the prion PrPC, and in mice which had differentiated B cells but no functional follicular dendritic cells. We conclude that differentiated B cells are crucial for neuroinvasion by scrapie, regardless of the specificity of their receptors.
TL;DR: It is reported that mice lacking Ras-GRF are impaired in the process of memory consolidation, as revealed by emotional conditioning tasks that require the function of the amygdala; learning and short-term memory are intact.
Abstract: Members of the Ras subfamily of small guanine-nucleotide-binding proteins are essential for controlling normal and malignant cell proliferation as well as cell differentiation. The neuronal-specific guanine-nucleotide-exchange factor, Ras-GRF/CDC25Mm, induces Ras signalling in response to Ca2+ influx and activation of G-protein-coupled receptors in vitro, suggesting that it plays a role in neurotransmission and plasticity in vivo. Here we report that mice lacking Ras-GRF are impaired in the process of memory consolidation, as revealed by emotional conditioning tasks that require the function of the amygdala; learning and short-term memory are intact. Electrophysiological measurements in the basolateral amygdala reveal that long-term plasticity is abnormal in mutant mice. In contrast, Ras-GRF mutants do not reveal major deficits in spatial learning tasks such as the Morris water maze, a test that requires hippocampal function. Consistent with apparently normal hippocampal functions, Ras-GRF mutants show normal NMDA (N-methyl-D-aspartate) receptor-dependent long-term potentiation in this structure. These results implicate Ras-GRF signalling via the Ras/MAP kinase pathway in synaptic events leading to formation of long-term memories.
TL;DR: Evidence is summarized here that the repetitiveness of many viral antigens is a key factor responsible for the efficiency of these B cell responses, amplifying B cells early and rapidly for potent IgM responses and also for efficient switching to IgG.
Abstract: Neutralizing antiviral B cell responses differ in various aspects from the many usually measured B cell responses specific for protein in adjuvants. In particular, such neutralizing antiviral B cell responses are more rapidly induced, reach higher titers, are longer lived, and are efficiently generated without adjuvants. Evidence is summarized here that the repetitiveness of many viral antigens is a key factor responsible for the efficiency of these B cell responses, amplifying B cells early and rapidly for potent IgM responses and also for efficient switching to IgG. The data reviewed indicate that B cells discriminate antigen patterns via the degree of surface Ig-cross-linking and use antigen repetitiveness as a self/nonself discriminator.
Journal Article•
TL;DR: The resorbable membrane, Bio-Gide, in combination with a bone graft, can be a useful alternative to the well-established expanded polytetrafluoroethylene membranes.
Abstract: The purpose of this clinical investigation was to compare the new resorbable collagen membrane, Bio-Gide, to the conventional expanded polytetrafluoroethylene material (Gore-Tex) for guided bone regeneration in situations involving exposed implant surfaces. Over a 2-year period, 25 split-mouth patients were treated randomly: one defect site was treated with Bio-Gide and the other defect site with Gore-Tex; all 84 defects were filled with Bio-Oss and covered with the respective membrane. The defect types, their dimensions, and their morphology were measured in detail initially and at re-entry to allow for calculation of the exposed implant surface. Changes in defect surface for both types of membranes were statistically significant (P .94) could be detected between the two membranes. The mean average percentage of bone fill was 92% for Bio-Gide and 78% for Gore-Tex sites. In the latter group, 44% wound dehiscences and/or premature membrane removal occurred. The resorbable membrane, Bio-Gide, in combination with a bone graft, can be a useful alternative to the well-established expanded polytetrafluoroethylene membranes.
TL;DR: Recent progress in engineering multivalency from recombinant antibody fragments by using miniantibodies (scFv fragments linked with hinges and oligomerization domains), spontaneous scFv dimers with short linkers (diabodies), or chemically crosslinked antibody fragments are summarized.
Journal Article•
TL;DR: In this article, the authors evaluated T-cell responses to mitogens and to defined antigens in breast cancer patients and found that significant defects in responses to tetanus toxoid and influenza virus were observed in patients with advanced-stage breast cancer.
Abstract: We evaluated T-cell responses to mitogens and to defined antigens in breast cancer patients. Significant defects in responses to tetanus toxoid and influenza virus were observed in patients with advanced-stage breast cancer. To define whether these defects were associated with a defect in antigen presentation [dendritic cells (DCs)] or effector function (T cells), these cells were studied separately. Purified DCs from 32 patients with breast cancer demonstrated a significantly decreased ability to stimulate control allogeneic T cells, but stimulation of patient T cells with either control allogeneic DCs or immobilized anti-CD3 antibody resulted in normal T-cell responses, even in patients with stage IV tumors. These data suggest that reduced DC function could be one of the major causes of the observed defect in cellular immunity in patients with advanced breast cancer. We then tested whether stem cells from these patients could give rise to functional DCs after in vitro growth with granulocyte/macrophage colony-stimulating factor and interleukin 4. Normal levels of control allogeneic and tetanus toxoid-dependent T-cell proliferation were observed when DCs obtained from precursors were used as stimulators. Those cells also induced substantially higher levels of influenza virus-specific CTL responses than mature DCs from the peripheral blood of these patients, although responses did not quite reach control values. Thus, defective T-cell function in patients with advanced breast cancer can be overcome by stimulation with DCs generated from precursors, suggesting that these cells may better serve as autologous antigen carriers for cancer immunotherapy than mature peripheral blood DCs.
TL;DR: Experimental results and sequence analysis suggest that an additional gene, males‐absent on the first (mof), encodes a putative acetyl transferase that plays a direct role in the specific histone acetylation associated with dosage compensation.
Abstract: Dosage compensation is a regulatory process that insures that males and females have equal amounts of X-chromosome gene products. In Drosophila, this is achieved by a 2-fold enhancement of X-linked gene transcription in males, relative to females. The enhancement of transcription is mediated by the activity of a group of regulatory genes characterized by the male-specific lethality of their loss-of-function alleles. The products of these genes form a complex that is preferentially associated with numerous sites on the X chromosome in somatic cells of males but not of females. Binding of the dosage compensation complex is correlated with a significant increase in the presence of a specific histone isoform, histone 4 acetylated at Lys16, on this chromosome. Experimental results and sequence analysis suggest that an additional gene, males-absent on the first (mof), encodes a putative acetyl transferase that plays a direct role in the specific histone acetylation associated with dosage compensation. The predicted amino acid sequence of MOF exhibits a significant level of similarity to several other proteins, including the human HIV-1 Tat interactive protein Tip60, the human monocytic leukemia zinc finger protein MOZ and the yeast silencing proteins SAS3 and SAS2.
TL;DR: In this paper, the authors obtained a practically complete next-to-leading order prediction for the branching ratio B(B→Xsγ) = (3.28 ± 0.33) × 10−4.
TL;DR: It is reported that mouse embryo fibroblasts from mutant mice containing homozygous deletions in the PKR gene (Pkr(0/0) mice) were resistant to apoptotic cell death in response to double-stranded RNA, tumor necrosis factor-alpha, or lipopolysaccharide.
Abstract: Apoptosis occurs in response to different cellular stresses, including viral infection, inflammatory cytokines, growth factor deprivation, and UV light, but it is unclear whether these inducers share a common mechanism of induction. The interferon-induced, double-stranded RNA-activated protein kinase (PKR) has been implicated in processes that rely on apoptosis as control mechanisms in vivo, including antiviral activities, cell growth regulation, and tumorigenesis. Here we report that mouse embryo fibroblasts from mutant mice containing homozygous deletions in the PKR gene (Pkro/o mice) were resistant to apoptotic cell death in response to double-stranded RNA, tumor necrosis factor-α, or lipopolysaccharide. The mechanism underlying the suppression of apoptosis in the Pkro/o cells could be attributed to defects in the activation of DNA-binding activity for the transcription factor interferon regulatory factor-1 and in Fas mRNA induction. Thus, these results provide genetic evidence implicating a requirement for PKR in mediating different forms of stress-related apoptosis.
TL;DR: It is indicated that oatp2 may play an especially important role in the brain accumulation and toxicity of digoxin and in the hepatobiliary and renal excretion of cardiac glycosides from the body.
Abstract: A novel multispecific organic anion transporting polypeptide (oatp2) has been isolated from rat brain. The cloned cDNA contains 3,640 bp. The coding region extends over 1,983 nucleotides, thus encoding a polypeptide of 661 amino acids. Oatp2 is homologous to other members of the oatp gene family of membrane transporters with 12 predicted transmembrane domains, five potential glycosylation, and six potential protein kinase C phosphorylation sites. In functional expression studies in Xenopus laevis oocytes, oatp2 mediated uptake of the bile acids taurocholate (Km ≈ 35 μM) and cholate (Km ≈ 46 μM), the estrogen conjugates 17β-estradiol-glucuronide (Km ≈ 3 μM) and estrone-3-sulfate (Km ≈ 11 μM), and the cardiac gylcosides ouabain (Km ≈ 470 μM) and digoxin (Km ≈ 0.24 μM). Although most of the tested compounds are common substrates of several oatp-related transporters, high-affinity uptake of digoxin is a unique feature of the newly cloned oatp2. On the basis of Northern blot analysis under high-stringency conditions, oatp2 is highly expressed in brain, liver, and kidney but not in heart, spleen, lung, skeletal muscle, and testes. These results provide further support for the overall significance of oatps as a new family of multispecific organic anion transporters. They indicate that oatp2 may play an especially important role in the brain accumulation and toxicity of digoxin and in the hepatobiliary and renal excretion of cardiac glycosides from the body.
TL;DR: A cell culture model capable of expressing Tf mRNA in an oxygen-dependent manner is presented, confirming that HIF-1 confers oxygen regulation of Tf gene expression by binding to the two HBSs present in the Tf enhancer.
TL;DR: It is proposed that expression of this SAG, induced in extrapancreatic and professional antigen-presenting cells, leads to beta-cell destruction via the systemic activation of autoreactive T cells, and constitutes a candidate autoimmune gene in type I diabetes.
TL;DR: Fulminant liver failure developed after the ingestion of food contaminated with the B. cereus emetic toxin, indicating that it caused liver failure in this patient.
Abstract: Background A 17-year-old boy and his father had acute gastroenteritis after eating spaghetti and pesto that had been prepared four days earlier. Within two days, fulminant liver failure and rhabdomyolysis developed in the boy and he died. The father had hyperbilirubinemia and rhabdomyolysis but recovered. We investigated the cause of these illnesses. Methods Bacteria were isolated and characterized by conventional methods, and bacterial toxins were quantified by immunoassays and cell-culture techniques. The effect of the isolated toxin on the rates of oxidation of various substrates was analyzed in rat-liver mitochondria. Results Autopsy of the boy's liver revealed diffuse microvesicular steatosis and midzonal necrosis that suggested impaired β-oxidation of liver mitochondria due to a mitochondrial toxin. There was no evidence of ingestion of heavy metals, halogenated compounds, hepatotoxic drugs, or staphylococcal enterotoxin. However, high concentrations of Bacillus cereus emetic toxin were found both i...