julilili42/papers huggingface dataset:
Signal Regulatory Protein (SIRPα), a Cellular Ligand for CD47, Regulates Neutrophil Transmigration
2002-03-01

Recent studies have demonstrated that CD47 plays an important role in regulating human neutrophil (PMN) chemotaxis. Two ligands for CD47, thrombospondin and SIRPalpha, have been described. However, it is not known if SIRP-CD47 interactions play a role in regulating PMN migration. In this study, we show that SIRPalpha1 directly binds to the immunoglobulin variable domain loop of purified human CD47 and that such SIRP-CD47 interactions regulate PMN transmigration. Specifically, PMN migration across both human epithelial monolayers and collagen-coated filters was partially inhibited by anti-SIRP monoclonal antibodies. Similar kinetics of inhibition were observed for PMN transmigration in the presence of soluble, recombinant CD47 consisting of the SIRP-binding loop. In contrast, anti-CD47 monoclonal antibodies inhibited PMN transmigration by markedly different kinetics. Results of signal transduction experiments suggested differential regulation of PMN migration by SIRP versus CD47 by phosphatidylinositol 3-kinase and tyrosine kinases, respectively. Immunoprecipitation followed by Western blotting after SDS-PAGE under nonreducing conditions suggested that several SIRP protein species may be present in PMN. Stimulation of PMN with fMLP resulted in increased surface expression of these SIRP proteins, consistent with the existence of intracellular pools. Taken together, these results demonstrate that PMN migration is regulated by CD47 through SIRPalpha-dependent and SIRPalpha-independent mechanisms.
Oxidation induces a Cl−‐dependent cation conductance in human red blood cells
2002-03-01

Oxidative stress induces complex alterations of membrane proteins in red blood cells (RBCs) eventually leading to haemolysis. To study changes of membrane ion permeability induced by oxidative stress, whole‐cell patch‐clamp recordings and haemolysis experiments were performed in control and oxidised human RBCs. Control RBCs exhibited a small cation‐selective whole‐cell conductance (236 ± 38 pS; n = 8) which was highly sensitive to the external Cl − concentration: replacement of NaCl in the bath by sodium gluconate induced an increase of this cation conductance by about 85 %. Exposing RBCs to t ‐butylhydroxyperoxide (1 m m for 10 min) induced a twofold increase in this cation conductance which was further stimulated after replacement of extracellular Cl − by gluconate, Br − , I − or SCN − . In addition, lowering the ionic strength of the bath solution by isosmotic substitution of NaCl by sorbitol activated the cation conductance. The Cl − ‐sensitive and oxidation‐induced cation conductance was Ca 2+ permeable, exhibited a permselectivity of Cs + &gt; K + &gt; Na + = Li + &gt;&gt; NMDG + , and was partially inhibited by amiloride (1 m m ) and almost completely inhibited by GdCl 3 (150 μ m ), but was insensitive to TEA, BaCl 2 , NPPB, flufenamic acid or quinidine. DIDS (100 μ m ) reversibly inhibited the activation of the cation conductance by removal of external Cl − . Oxidation induced haemolysis in NaCl ‐bathed human RBCs. This haemolysis was attenuated by amiloride (1 m m ) and inhibited by replacement of bath Na + by the impermeant cation NMDG + . The Na + ‐ and Ca 2+ ‐permeable conductance might be involved in haemolytic diseases induced by elevated oxidative stress, such as glucose‐6‐phosphate dehydrogenase deficiency.
Glucocorticoid Activation of Na+/H+Exchanger Isoform 3 Revisited
2002-03-01

The stimulative effect of glucocorticoids on intestinal salt and water absorption has been known for more than two decades. However, molecular mechanisms underlying this activation remain elusive. Previous studies showed that methylprednisolone specifically increased Na(+)/H(+) exchanger isoform (NHE) 3 mRNA in ileum and kidney without affecting NHE1 mRNA levels. These results suggest that glucocorticoids activate NHE3 activity by induction of NHE3 transcripts. We recently found in PS120 and opossum kidney cells that chronic incubation with dexamethasone activated NHE3 independent of gene induction, indicating that the transcriptional activation may not be the only determining factor in the NHE3 activation. Furthermore, dexamethasone activated NHE3 activity only in the presence of a NHE3 regulatory protein, NHERF2, which was previously shown to confer cAMP-dependent inhibition of NHE3. This activation of NHE3 could not be duplicated by NHERF1. We identified serum- and glucocorticoid-induced protein kinase, SGK1, as the protein interacting with PDZ domains of NHERF2 to regulate NHE3 activity. The expression of SGK1 enhanced NHE3 transport in PS120 fibroblasts. In addition, the "kinase-dead" SGK1 blocked activation of NHE3 by dexamethasone in opossum kidney cells. These data demonstrated that glucocorticoid activation of NHE3 requires the activation of SGK1 and the presence of NHERF2 acting as a scaffold protein.
Identification of T-cell epitopes in the structural and non-structural proteins of classical swine fever virus
2002-03-01

To identify new T-cell epitopes of classical swine fever virus (CSFV), 573 overlapping, synthetic pentadecapeptides spanning 82% of the CSFV (strain Glentorf) genome sequence were synthesized and screened. In proliferation assays, 26 peptides distributed throughout the CSFV viral protein sequences were able to induce specific T-cell responses in PBMCs from a CSFV-Glentorf-infected d/d haplotype pig. Of these 26 peptides, 18 were also recognized by PBMCs from a CSFV-Alfort/187-infected d/d haplotype pig. In further experiments, it could be shown that peptide 290 (KHKVRNEVMVHWFDD), which corresponds to amino acid residues 1446–1460 of the CSFV non-structural protein NS2–3 could induce interferon-γ secretion after secondary in vitro restimulation. The major histocompatibility complex (MHC) restriction for stimulation of T-cells by this pentadecapeptide was identified as being mainly MHC class II and partially MHC class I. In cytolytic assays, CSFV-specific cytotoxic T-lymphocytes (CTLs) were able to lyse peptide 290-loaded target cells. These findings indicate the existence of a CSFV-specific helper T-cell epitope and a CTL epitope in this peptide.
The Flavoprotein MrsD Catalyzes the Oxidative Decarboxylation Reaction Involved in Formation of the Peptidoglycan Biosynthesis Inhibitor Mersacidin
2002-03-01

ABSTRACT The lantibiotic mersacidin inhibits peptidoglycan biosynthesis by binding to the peptidoglycan precursor lipid II. Mersacidin contains an unsaturated thioether bridge, which is proposed to be synthesized by posttranslational modifications of threonine residue +15 and the COOH-terminal cysteine residue of the mersacidin precursor peptide MrsA. We show that the flavoprotein MrsD catalyzes the oxidative decarboxylation of the COOH-terminal cysteine residue of MrsA to an aminoenethiol residue. MrsD belongs to the recently described family of homo-oligomeric flavin-containing Cys decarboxylases (i.e., the HFCD protein family). Members of this protein family include the bacterial Dfp proteins (which are involved in coenzyme A biosynthesis), eukaryotic salt tolerance proteins, and further oxidative decarboxylases such as EpiD. In contrast to EpiD and Dfp, MrsD is a FAD and not an FMN-dependent flavoprotein. HFCD enzymes are characterized by a conserved His residue which is part of the active site. Exchange of this His residue for Asn led to inactivation of MrsD. The lantibiotic-synthesizing enzymes EpiD and MrsD have different substrate specificities.
Evolution of the Concept of Angulated Abutments in Implant Dentistry:14-year Clinical Data
2002-03-01

This paper describes the evolution of the concept of selecting the abutment at first-stage surgery and presents clinical data accumulated over 14 years of the use of this concept with angulated abutments. The concept was developed for implants using internal and external hexed connections and has evolved in its use for implants using a Morse taper connection as a result of the considerable clinical advantages that this type of connection offers. A total of 3101 implants were restored using angled abutments ranging from 0 to 45 degrees and were observed over a period of up to 151 months. After an observation time of 120 months (10 years) after placement, the calculated 95% confidence interval of the mean survival estimation, according to Aalen et al, was 98.2% (+/- 0.7%). The magnitude of the angles did not influence the survival rate. The need to refine the implant position in terms of the depth to which it was placed and the angulation and rotational orientation, as well as the size and pivot point of the final abutment, were recognized as contributing to the harmonious emergence profile of the restoration. Good esthetic and functional outcomes were achieved by the use of conventional cement-retained restorations made possible by parallel and aligned abutments.
Malaria therapy reinoculation data suggest individual variation of an innate immune response and independent acquisition of antiparasitic and antitoxic immunities
2002-03-01

Malaria therapy reinoculation data were examined for the possible detection of effects attributable to stable individual host-specific factors, through correlation between descriptive variables of first and second infections. Such an effect was demonstrated with respect to the first local maximum of the asexual parasite density, i.e., the density at which a host controls parasite growth. The effect was seen between an individual host's first and second Plasmodium falciparum infection, as well as between an individual host's first malaria infection with P. ovale and second malaria infection with P. falciparum. We give reasons to believe that the main underlying mechanism is individual variation of an innate immune response. The data were also examined for systematic changes from first to second P. falciparum infection, as indicators of acquired immunity. In addition to the well-known reduction in parasite density, the data show the early development of apparent parasite tolerance. We give reasons to interpret the latter as antitoxic immunity.
Prevalence of Functional Bowel Disorders and Related Health Care Seeking: A Population-Based Study
2002-03-01

A high prevalence of functional bowel disorders was found in this population-based study in Germany. Only about half of the subjects reported health care seeking due to their bowel disorders. Self-medication with over-the-counter agents was frequently performed.
Effects of pinealectomy and melatonin on the retrograde degeneration of retinal ganglion cells in a novel model of intraorbital optic nerve transection in mice
2002-03-01

The effects of pinealectomy and of intraperitoneally administered melatonin on the retrograde degeneration of retinal ganglion cells (RGCs) were examined in a novel model of optic nerve (ON) transection in C57BL/6J mice. RGCs were prelabeled with the fluorescent tracer 1,1′‐dioctadecyl‐3,3,3′,3′‐tetramethyl indocarbocyanine perchlorate (Di‐I), and the ON was cut inside the orbital cavity 7 days later. The degree of RGC injury was assessed by counting viable Di‐I labeled RGCs in various locations of the retina. In unlesioned control eyes, a mean ganglion cell density of 1891 ± 30/mm 2 (mean ± S.E.M.) was determined. The cell density markedly declined at 14 days after axotomy (295 ± 9 cells/mm 2 ; 15.6% of contralateral). Sham‐pinealectomy did not influence the density of RGCs at 14 days after ON transection (382 ± 37 cells/mm 2 ). In pinealectomized animals, on the other hand, the RGC number was significantly reduced as compared with untreated and sham‐pinealectomized animals (91 ± 33 RGCs/mm 2 ). The effect of pinealectomy was reversed after i.p. administration of melatonin (4 mg/kg bw bolus followed by continuous infusion of 8 mg/kg bw/day) (286 ± 27 cells/mm 2 ). In nonpinealectomized animals, on the contrary, i.p. melatonin did not influence the RGC density (344 ± 20 cells/mm 2 ). The present results suggest that endogenous melatonin prevents the delayed degeneration of adult central nervous system (CNS) neurons in vivo, and that exogenous substitution of melatonin may be useful to protect injured neurons against cell death under conditions of melatonin deficiency, e.g. in the aged brain, when melatonin synthesis and secretion have decreased.
Human plasma thrombopoietin levels are regulated by binding to platelet thrombopoietin receptors in vivo
2002-03-01

BACKGROUND: Data from several studies support the hypothesis that thrombopoietin (TPO) plasma levels are regulated via circulating platelet (PLT) numbers by binding to PLT TPO receptors (TPO‐Rs). In this study, PLT numbers and TPO plasma levels were measured following the transfusion of unmanipulated, sham‐saturated, and TPO‐R‐saturated PLT preparations to provide additional in vivo evidence for this regulatory mechanism. STUDY DESIGN AND METHODS: Following in vitro experiments to characterize pegylated recombinant human megakaryocyte growth and development factor (PEG‐rHuMGDF) binding characteristics, PLT numbers and TPO plasma levels were measured following the transfusion of unmanipulated, sham‐saturated, and TPO‐R‐saturated PLT preparations in thrombocytopenic patients. Sham‐saturated and TPO‐R‐saturated PLTs were prepared by a 1‐hour incubation without and with 40 ng per mL of PEG‐rHuMGDF, respectively, and subsequent washing and resuspension. RESULTS: In vitro, 2.72 ± 0.8 ng of PEG‐rHuMGDF per 1 × 10 8 PLTs was bound within 1 hour of incubation. No additional PEG‐rHuMGDF was bound following a second incubation with PEG‐rHuMGDF, and bound PEG‐rHuMGDF was not released over time. In vivo, TPO plasma levels decreased significantly (p &lt; 0.001), by 30.7 ± 5.8 and 20.9 ± 2.1 percent after transfusion of unmanipulated and sham‐saturated PLT preparations, respectively. However, TPO plasma levels were unaffected after the transfusion of TPO‐R‐saturated PLTs despite comparable transfusion‐induced PLT count increases. CONCLUSION: These data strongly support the concept that binding to PLT TPO‐R is directly involved in human TPO plasma level regulation in vivo.
A Non-Invasive Communication Device for the Paralyzed
2002-03-01

An EEG-based communication system has been developed to re-establish communication in severely paralyzed patients who operate the device by generating shifts of their slow cortical potentials. Training to gain control over slow cortical potentials was based on visual feedback and operant conditioning strategies. The vertical movement of a graphic signal on a computer screen informs the patients about the course of their slow cortical potential amplitude. Positive slow cortical potential shifts move the cursor up, negative shifts move it down. These shifts are then translated into binary responses. When a patient has achieved reliable control over his/her slow cortical potential shifts, these responses can be used to select or reject items presented at the bottom of the screen. As learning processes and applications differ considerably between patients, the present paper describes the data from one patient with amyotrophic lateral sclerosis. After about three months of training, this patient gained stable, near-perfect control over his slow cortical potentials. This skill enabled him to operate a specially designed program to communicate messages to his caregivers.
Detection of Cryptococcus neoformans DNA in Tissue Samples by Nested and Real-Time PCR Assays
2002-03-01

ABSTRACT Two PCR protocols targeting the 18S rRNA gene of Cryptococcus neoformans were established, compared, and evaluated in murine cryptococcal meningitis. One protocol was designed as a nested PCR to be performed in conventional block thermal cyclers. The other protocol was designed as a quantitative single-round PCR adapted to LightCycler technology. One hundred brain homogenates and dilutions originating from 20 ICR mice treated with different azoles were examined. A fungal burden of 3 × 10 1 to 2.9 × 10 4 CFU per mg of brain tissue was determined by quantitative culture. Specific PCR products were amplified by the conventional and the LightCycler methods in 86 and 87 samples, respectively, with products identified by DNA sequencing and real-time fluorescence detection. An analytical sensitivity of 1 CFU of C. neoformans per mg of brain tissue and less than 10 CFU per volume used for extraction was observed for both PCR protocols, while homogenates of 70 organs from mice infected with other fungi were PCR negative. Specificity testing was performed with genomic DNA from 31 hymenomycetous fungal species and from the ustilaginomycetous yeast Malassezia furfur , which are phylogenetically related to C. neoformans . Twenty-four strains, including species of human skin flora like M. furfur and Trichosporon spp., were PCR negative. Amplification was observed with Cryptococcus amylolentus , Filobasidiella depauperata , Cryptococcus laurentii , and five species unrelated to clinical specimens. LightCycler PCR products from F. depauperata and Trichosporon faecale could be clearly discriminated by melting curve analysis. The sensitive and specific nested PCR assay as well as the rapid and quantitative LightCycler PCR assay might be useful for the diagnosis and monitoring of human cryptococcal infections.
Mapping of B-Cell Epitopes in the Nucleocapsid Protein of Puumala Hantavirus
2002-03-01

Hantavirus nucleocapsid protein (N) has been proven to induce highly protective immune responses in animal models. The knowledge on the mechanisms behind N-induced protection is still limited, although recent data suggest that both cellular and humoral immune responses are of importance. For a detailed B-cell epitope mapping of Puumala hantavirus (PUUV) N, we used recombinant N derivatives of the Russian strain CG18-20 and the Swedish strain Vranica/Hällnäs, as well as overlapping synthetic peptides corresponding to the Finnish prototype strain Sotkamo. The majority of a panel of monoclonal antibodies (mAbs) reacted with proteins derived from all included PUUV strains demonstrating the antigenic similarity of these proteins. In line with previous results, the epitopes of most mAbs were mapped within the 80 N-terminal amino acids of N. The present study further revealed that the epitopes of four mAbs raised against native viral N were located within amino acids 14–45, whereas one mAb raised against recombinant N was mapped to amino acids 14–39. Differences between the reactivity of the PUUV strains Vranica/Hällnäs and CG18-20 N suggested the importance of amino acid position 35 for the integrity of the epitopes. In line with the patterns obtained by the truncated recombinant proteins, mapping by overlapping peptides (PEPSCAN) confirmed a complex recognition pattern for most analyzed mAbs. Together, the results revealed the existence of several, partially overlapping, and discontinuous B-cell epitopes. In addition, based on differences within the same competition group, novel epitopes were defined.
Identification of inhibitor‐of‐differentiation 2 (Id2) as a modulator of neuronal apoptosis
2002-03-01

Abstract Inhibitor‐of‐differentiation 2 (Id2) belongs to a family of transcriptional modulators that are characterized by a helix loop helix region but lack the basic amino acid domain. During development, Id2 antagonizes differentiation mediated by the retinoblastoma protein, probably by scavenging downstream E‐box basic helix‐loop‐helix proteins. Here, using differential display RT‐PCR, we identify Id2 as an induced gene during serum and potassium deprivation‐induced apoptosis of cerebellar granule neurons. Consistent with a biological role for induced Id2 messenger RNA and protein expression in neuronal cell death, expression of Id2 antisense RNA, or targeted deletion of the Id2 gene in neurons from Id2 knock‐out mice, protect from apoptosis. Further, gene transfer‐ mediated overexpression of Id2 induces neuronal cell death both in high potassium and low potassium conditions. Thus, the present study defines a role for Id2 in the modulation of neuronal apoptosis.
Virtual coronary angioscopy using multislice computed tomography
2002-03-01

Background: With faster image acquisition times and thinner slice widths, multislice detector computed tomography (MSCT) allows visualisation of human coronary arteries with diagnostic image quality. In addition to conventional axial slices, virtual coronary angioscopies (VCA) can be reconstructed using MSCT datasets. Objective: To evaluate the feasibility of reconstructing VCA and to determine the clinical value of this new application in detecting atherosclerotic coronary artery lesions. Methods: Datasets obtained by contrast enhanced non-invasive coronary angiography using MSCT (Somatom VZ) were analysed from 14 consecutive patients. VCA were simulated in 14 coronary arteries (left anterior descending, n = 7; right coronary, n = 7). Lesion detection was undertaken on conventional contrast enhanced axial slices, as well as by VCA. Intracoronary ultrasound (ICUS) was used as the gold standard for in vivo plaque detection. Results: 38 lesions were detected both on ICUS and on axial slices: 14 severe target lesions of &gt; 75% area stenosis (11 calcified, three non-calcified), and 24 intermediate lesions of ≤ 75% area stenosis (seven calcified, 17 non-calcified). Using VCA, all severe lesions (n = 14) and all calcified intermediate plaques (n = 7) could clearly be identified. However, non-calcified intermediate lesions (n = 17) could not be accurately distinguished from the vessel wall; they were recognised as vessel wall alterations without significant luminal narrowing. Conclusions: Current MSCT technology allows reconstruction of VCA with good image quality. Despite a more anatomical view of heart and coronary vessels on three dimensional reconstruction, conventional axial slices were found to be superior for detecting coronary lesions. Thus further technical innovations are required before VCA can become a useful technique in clinical cardiology.
Influence of controlled hypoxia and radical scavenging agents on erythropoietin and malondialdehyde concentrations in humans
2002-03-01

The present study was carried out to evaluate a model of a hypoxic stimulus of erythropoietin (EPO) production in humans and to investigate the role of free oxygen radicals in human EPO production. The study was conducted as an open, randomized, parallel, placebo‐controlled trial. Thirty‐six healthy male volunteers received a hypoxic treatment (13% O 2 ) with a respiration mask for 6 h. During the period of hypoxia, the volunteers received as a short‐term treatment either 1200 mg thioctic acid, or N ‐acetylcysteine 600 mg or placebo (0.9% sodium chloride). The EPO concentration in plasma increased up to 290% of the baseline level in all three groups. No statistically significant differences of AUC EPO(0–48 h) could be demonstrated between the groups. The malondialdehyde (MDA) concentration in plasma increased significantly ( P &lt; 0.001) 2 h after termination of hypoxia (mean 129.8 ± 6.8% of the baseline) in all three groups. Conclusions : Taken together, our in‐vivo results do not support a gross modulatory effect of a short‐term treatment with radical scavenging agents on EPO‐production during or after hypoxia in humans, as derived from the detected changes of MDA‐concentrations in peripheral plasma.
Isolation and Structure Elucidation of Two New Xanthones from Gentiana azurium Bunge (Fam. Gentianaceae)
2002-03-01

Abstract Two new natural xanthones, 1,3,5-trihydroxy-8-methoxyxanthone (1) and 3,5-dihydroxy-8- methoxy-1-O-β-D-glucopyranosyl xanthone (2) were isolated along with two known xanthones from Gentiana azurium Bunge (Fam. Gentianaceae). Their structures were determined on the basis of their spectral data.