julilili42/papers huggingface dataset:
Insulin-Like Growth Factor-I Protects Axotomized Rat Retinal Ganglion Cells from Secondary Death via PI3-K-Dependent Akt Phosphorylation and Inhibition of Caspase-3In Vivo
2000-01-15

Recently we have shown that the majority of retinal ganglion cells (RGCs) dies via activation of caspase-3 after transection of the optic nerve (ON) in the adult rat. In the present study we investigated whether insulin-like growth factor-I (IGF-I), an important factor in retinal development, prevents secondary death of RGCs after axotomy. Moreover, we studied potential intracellular mechanisms of IGF-mediated neuroprotection in more detail. Our results indicate that intraocular application of IGF-I protects RGCs from death after ON transection in a dose-dependent manner. We show reduced caspase-3 activity as one possible neuroprotective mechanism of IGF-I treatment in vivo . Caspase-3 mRNA expression remained unchanged. Because caspase inhibition can be mediated by Akt in vitro, we examined phosphorylation of Akt after axotomy and under IGF treatment. Western blot analysis revealed decreased Akt phosphorylation after axotomy without treatment and an increased phosphorylation of Akt under treatment with IGF-I. This strong increase could be reduced by simultaneous injection of wortmannin (WM), a potent inhibitor of phosphatidylinositol 3-kinase (PI3-K). To prove the pathway suggested by these experiments as relevant for the in vivo situation, we assessed the number of RGCs 14 d after ON transection under a combined treatment strategy of IGF-I and WM. As expected, WM significantly reduced the neuroprotective effects of IGF-I. In summary, we show for the first time in vivo that IGF is neuroprotective via PI3-K-dependent Akt phosphorylation and by inhibition of caspase-3.
The impact of untreated coronary dissections on acute and long-term outcome after intravascular ultrasound guided PTCA
2000-01-15

According to the theory of 'therapeutic dissections', our data suggest that substantial dissections following PTCA, which do not diminish antegrade blood flow, do not lead to an increase in acute or long-term events. The natural history of vessel injury seems to provide favourable wound healing without increase of restenosis. Thus, stenting for treatment of large dissections without flow limitation does not seem to be mandatory.
Extension of HLA-A*0201-Restricted Minimal Epitope by Nε-Palmitoyl-lysine Increases the Life Span of Functional Presentation to Cytotoxic T Cells
2000-01-15

Abstract The delineation of the minimal requirements for efficient delivery of functional cytotoxic epitopes into APC could be a step toward the definition of “minimal length” lipopeptides for the modulation of CTL activity. Several analogues of the HLA-A*0201-restricted HIV-1 polymerase (pol476–484) minimal cytotoxic epitope were obtained by modifying P0, P1, or P10 positions by a single Nε-palmitoyl-lysine residue. The use of fluorescent derivatives confirmed the cell-permeating activities and suggested that a P0- and a P1-modified lipopeptide possessing ionizable extremities fulfills the structural requirements for MHC loading. The expressions of HLA-peptide complexes at the surface of TAP-deficient cells incubated with the parent epitope or lipopeptide derivatives were compared, in terms of intensity and stability. Both lipopeptides induced a considerably prolonged expression of conformationally correct complexes, which were dependent on the integrity of the exocytosis pathway, suggesting a dynamic mechanism of formation or reloading of the complexes from an intracellular pool. The agonistic activities of the different HLA-peptide complexes were evaluated using two independent T cell lines from HIV-infected donors. We report that a lipodecapeptide obtained by N-terminal addition of a Nε-palmitoyl-lysine to the pol476–484 epitope was able to increase the life span of functional presentation to cytotoxic T cells specific for the parent peptide.
N, O‐Dimethyl‐N‐Silylhydroxylamine, a Compound with Steeply Pyramidal Nitrogen Coordination
2000-01-17

N, O-Dimethyl-N-silylhydroxylamine, H3SiMeNOMe, has been prepared by reaction of HMeNOMe with H3SiBr and 2, 6-lutidine as an auxiliary base. The solution NMR data indicate aggregation of the compound. H3SiMeNOMe decomposes at ambient temperature and formation of methylnitrene is probably a first step in the mechanism. The energy of H3SiMeNOMe relative to its potential rearrangement isomer MeHN-H2Si-OMe has been estimated by ab initio calculations to be 289 kJ mol-1. The molecular structure of H3SiMeNOMe has been determined by gas-phase electron diffraction and by ab initio calculations. H3SiMeNOMe possesses a steeply pyramidal nitrogen atom. Hence it is the first silylamine reported with a typically pyramidal nitrogen coordination for electronic reasons. Results of an NBO analysis are discussed to rationalize the bonding situation.
Exploratory saccades show no direction-specific deficit in neglect
2000-01-25

In patients with spatial neglect, contralesional reflexive saccades toward suddenly appearing targets show direction-specific deficits. We examined whether these deficits also occur during free exploration of space. Neglect patients' voluntary eye movements showed reduced amplitudes for saccades in all directions but no direction-specific deficit. The results argue against an interpretation of spatial neglect as a general deficit to disengage attention or to program saccades in contralesional direction.
No induction of apoptosis by IFN-β in human antigen-specific T cells
2000-01-25

Interferon (IFN)-beta, the most effective immunomodulatory treatment for MS, inhibits the proliferation of myelin-specific T cells. We report that IFN-beta moderately enhances the expression of the death receptor, CD95, at the surface of human antigen-specific T cells. However, T-cell apoptosis was not induced by IFNbeta-1a or IFNbeta-1b as assessed by caspase activity or DNA fragmentation. Immunomodulation mediated by IFN-beta does not directly involve apoptotic pathways in human T cells.
Evaluation of 2,3,7,8 Specific Congener and Toxic Potency of Persistent Polychlorinated Dibenzo-p-Dioxins and Polychlorinated Dibenzofurans in Cetaceans from the Mediterranean Sea, Italy
2000-01-28

The present study investigates individual 2,3,7,8-substituted polychlorinated dibenzo-p-dioxin (PCDD) and polychlorinated dibenzofuran (PCDF) concentrations in cetaceans and assesses the PCDD and PCDF contributions to the total TCDD equivalent concentration. Liver samples of a variety of cetaceans species found stranded along the Italian coasts during the period of 1987−1992 were analyzed for PCDDs and PCDFs. The main aims were to scrutinize levels and patterns of PCDDs and PCDFs for the first time in cetaceans from the Mediterranean Sea and to estimate whether chlorinated compounds mentioned are implicated in the exceptionally high mortality of dolphins that occurred in the Mediterranean Sea during 1990−1992. PCDD and PCDF profiles were dominated by congeners OCCD and OCDF. The new toxic equivalency factors recommended by WHO in 1997 were used for calculation of dioxin-like toxicity. On the basis of our previous study of PCBs, the overall TEQ calculated from the 2,3,7,8-substituted PCDDs and PCDFs do not contribute as much dioxin-like toxicity as PCBs.
Methoden
2000-01-28

Methoden zur Bestimmung multipler Gleichgewichte Gleichgewichtsdialyse und allgemeine Aspekte von Bindungsmessungen Prinzip der Gleichgewichtsdialyse Kontrollexperimente und Fehlerquellen Kontinuierliche Gleichgewichtsdialyse Ultrafiltration Gelfiltration Batchverfahren Elution breiter Zonen Verfahren nach Hummel und Dreyer Verfahren nach Brumbaugh und Ackers Ultrazentrifugationsmethoden Einfache Ultrazentrifugation Zentrifugationsmethode von Chanutin et al. (1942) Rohrzuckergradientenzentrifugation nach Draper und Hippel Elektrochemische Methoden Sauerstoffelektrode CO2-Elektrode Potentiometrie, Oxidations-Reduktions-Potentiale pH-Stat Polarographie Kalorimetrie Spektroskopische Methoden Absorptionsspektroskopie Lambert-Beersches Gesetz Spektrale Eigenschaften von Enzymen und Liganden Aufbau von Spektralphotometern Doppelstrahl-Spektralphotometer Differenzspektroskopie Doppelwellenlängen-Spektralphotometer Photochemische Aktionsspektren Biolumineszenz Fluoreszenz Quantenausbeute Störungen von Fluoreszenzmessungen Fluoreszierende Verbindungen (Fluorophore) Aufbau von Spektralfluorimetern Strahlungslose Energieübertragung Fluoreszenzpolarisation Pulsfluorimetrie Circulardichroismus und optische Rotationsdispersion Infrarot- und Raman-Spektroskopie IR-Spektroskopie Raman-Spektroskopie Anwendungen Elektronenspinresonanz-Spektroskopie Messung schneller Reaktionen Flußmethoden Continuous-Flow-Methode Stopped-Flow-Methode Messung von Enzymreaktionen durch Flußmethoden Bestimmung der Totzeit Relaxationsmethoden Temperatursprung-Methode Drucksprung-Methode Feldsprung-Methode Flash-Photolyse, Pico- und Femtosekunden-Spektroskopie Auswertung schneller kinetischer Reaktionen (Transient-Kinetik) Literatur
TeXshade: shading and labeling of multiple sequence alignments using LaTeX2e
2000-02-01

Abstract Motivation: Typesetting, shading and labeling of nucleotide and peptide alignments using standard word processing or graphics software is time consuming. Available automatic sequence shading programs usually do not allow manual application of additional shadings or labels. Hence, a flexible alignment shading package was designed for both calculated and manual shading, using the macro language of the scientific typesetting software LaTeX2e. Results: TeXshade is the first TeX-based alignment shading software featuring, in addition to standard identity and similarity shading, special modes for the display of functional aspects such as charge, hydropathy or solvent accessibility. A plenitude of commands for manual shading, graphical labels, re-arrangements of the sequence order, numbering, legends etc. is implemented. Further, TeXshade allows the inclusion and display of secondary structure predictions in the DSSP-, STRIDE- and PHD-format. Availability: From http://homepages.uni-tuebingen.de/beitz/tse.html(macro package and on-line documentation) Contact: eric.beitz@uni-tuebingen.de
Quantification of Fungal DNA by Using Fluorescence Resonance Energy Transfer and the Light Cycler System
2000-02-01

ABSTRACT The Light Cycler technique combines rapid in vitro amplification of DNA in glass capillaries with real-time species determination and quantification of DNA load. We have established a quantitative PCR protocol for two clinically important pathogens, Candida albicans and Aspergillus fumigatus . The sensitivity of the assay was comparable to those of previously described PCR protocols (5 CFU/ml). Specific detection of C. albicans and A. fumigatus could be achieved. The assay showed a high reproducibility of 96 to 99%. The assay was linear in a range between 10 1 and 10 4 Aspergillus conidia. As capillaries do not have to be reopened for post-PCR analysis, the risk of carryover contaminations could be minimized. The Light Cycler allowed quantification of the fungal loads in a limited number of clinical specimens from patients with hematological malignancies and histologically proven invasive fungal infections. Five of nine positive samples had fungal loads between 5 and 10 CFU/ml of blood, two of nine positive samples had fungal loads between 10 and 100 CFU/ml of blood, and two of nine samples had fungal loads of more than 100 CFU/ml of blood. All samples were also found to be PCR positive by PCR–enzyme-linked immunosorbent assay analysis.
Monocyte-derived dendritic cells are permissive to the complete replicative cycle of human cytomegalovirus
2000-02-01

The susceptibility of monocyte-derived immature dendritic cells (DC) to infection by various strains of human cytomegalovirus (HCMV) was analysed. Immature DC were generated by incubation of peripheral blood monocytes with interleukin-4 and granulocyte–macrophage colony-stimulating factor for 7 days and were characterized by a CD1a+/CD40+/CD80+/CD86+/HLA-DR+/CD14− phenotype. Viral antigen expression and production of infectious progeny virus were analysed in infected immature DC cultures. Immature DC were 80–90 % susceptible to HCMV strains that had been propagated in endothelial cell culture, whereas the infection rate was negligible with fibroblast-adapted HCMV strains. Immature DC infection resulted in expression of viral immediate early, early and late genes. Productive infection was proven by the detection of infectious virus in single-step growth curves and in infectious centre assays. It is concluded that HCMV might interfere with the host immune reaction by permissive, lytic infection of immature DC.
Surface Signaling in Ferric Citrate Transport Gene Induction: Interaction of the FecA, FecR, and FecI Regulatory Proteins
2000-02-01

ABSTRACT In Escherichia coli , transcription of the ferric citrate transport genes fecABCDE is controlled by a novel signal transduction mechanism that starts at the cell surface. Binding of ferric citrate to the outer membrane protein FecA initiates a signal that is transmitted by FecR across the cytoplasmic membrane into the cytoplasm where FecI, the sigma factor, is activated. Interaction between the signaling proteins was demonstrated by utilizing two methods. In in vitro binding assays, FecR that was His tagged at the N terminus [(His) 10 -FecR] and bound to a Ni-nitrilotriacetic acid agarose column was able to retain FecA, and FecR that was His tagged at the C terminus [FecR-(His) 6 ] retained FecI on the column. An N-terminally truncated, induction-negative but transport-active FecA protein did not bind to (His) 10 -FecR. The in vivo assay involved the determination of the FecA, FecR, and FecI interacting domains with the bacterial two-hybrid Lex-based system. FecA 1–79 interacts with FecR 101–317 and FecR 1–85 interacts with FecI 1–173 . These data clearly support a model that proposes interaction of the periplasmic N terminus of FecA with the periplasmic C-terminal portion of FecR and interaction of the cytoplasmic N terminus of FecR with FecI, which results in FecI activation.
Stereointegrity of Tröger's Base:  Gas-Chromatographic Determination of the Enantiomerization Barrier
2000-02-01

Tröger's base 1 (2,8-dimethyl-6H,12H-5,11-methanodibenzo[b,f][1,5]diazocine) undergoes enantiomerization in the gas and liquid phases. By enantioselective stopped-flow multidimensional gas chromatography, Eyring activation parameters of the enantiomerization barrier have been determined in the inert mobile gas phase (helium): ΔG⧧gas(298.15 K) = 112.8 ± 0.5 kJ mol-1; ΔH⧧gas = 62.7 ± 0.3 kJ mol-1; ΔS⧧gas = −168 ± 6 J (K mol)-1. An enantiomerization pathway proceeding via a degenerated retro-hetero-Diels−Alder ring opening or formation of a zwitterionic structure of 1 is proposed. By enantioselective dynamic gas chromatography, Eyring activation parameters have also been determined via computer-aided simulation of experimental interconversion peak profiles in the chiral stationary liquid phase: ΔG⧧liq(298.15 K) = 117.8 ± 0.5 kJ mol-1; ΔH⧧liq = 48.9 kJ mol-1; ΔS⧧liq = −231 ± 8 J (K mol)-1. Surprisingly, in the presence of the chiral stationary phase (CSP) Chirasil-β-Dex, required for enantiomer separation of 1, the enantiomerization barrier is higher than in the gas phase. The concept of the retention increment R' has been applied to distinguish the enantiomerization barrier of 1 in the dissolved and complexed state of the stationary phase.
Amino Acid Transporters Are Localized to Transfer Cells of Developing Pea Seeds
2000-02-01

Abstract To determine the nature and cellular localization of amino acid transport in pea seeds, two cDNA clones belonging to the AAP family of H+/amino acid co-transporters (PsAAP1 and PsAAP2) were isolated from a cotyledon cDNA library of pea (Pisum sativum L.). Functional expression in the yeast amino acid uptake mutants 22Δ6AAL and 22Δ8AA showed that PsAAP1 mediates transport of neutral, acidic, and basic amino acids. RNA-blot analyses showed that PsAAP1 is expressed in seeds and vegetative organs, including amino acid sinks and sources, whereasPsAAP2 could not be detected. For developing seeds, transcripts of PsAAP1 were detected in coats and cotyledons, with seed coats giving a weak signal. In cotyledons, expression was highest in epidermal-transfer-cell-enriched tissue. RNA in situ hybridization analysis showed that PsAAP1 was predominantly present in epidermal transfer cells forming the outer surface of cotyledons, which abuts the seed coats. Overall, our observations suggest that this transporter, which is localized in transfer cells of cotyledons, might play a role in the uptake of the full spectrum of amino acids released from seed coats.
Hypersensitivity of an Arabidopsis Sugar Signaling Mutant toward Exogenous Proline Application
2000-02-01

Abstract In transgenic Arabidopsis a patatin class I promoter from potato is regulated by sugars and proline (Pro), thus integrating signals derived from carbon and nitrogen metabolism. In both cases a signaling cascade involving protein phosphatases is involved in induction. Other endogenous genes are also regulated by both Pro and carbohydrates. Chalcone synthase (CHS) gene expression is induced by both, whereas the Pro biosynthetic Δ1-pyrroline-5-carboxylate synthetase (P5CS) is induced by high Suc concentrations but repressed by Pro, and Pro dehydrogenase (ProDH) is inversely regulated. The mutantrsr1-1, impaired in sugar dependent induction of the patatin promoter, is hypersensitive to low levels of external Pro and develops autofluorescence and necroses. Toxicity of Pro can be ameliorated by salt stress and exogenously supplied metabolizable carbohydrates. The rsr1-1 mutant shows a reduced response regarding sugar induction of CHS andP5CS expression. ProDH expression is de-repressed in the mutant but still down-regulated by sugar. Pro toxicity seems to be mediated by the degradation intermediate Δ1-pyrroline-5-carboxylate. Induction of the patatin promoter by carbohydrates and Pro, together with the Pro hypersensitivity of the mutant rsr1-1, demonstrate a new link between carbon/nitrogen and stress responses.
Analyzing X‐Ray Pulsar Profiles: Geometry and Beam Pattern of Hercules X‐1
2000-02-01

We report on our analysis of a large sample of energy dependent pulse profiles of the X-ray binary pulsar Hercules X-1. We find that all data are compatible with the assumption of a slightly distorted magnetic dipole field as sole cause of the asymmetry of the observed pulse profiles. Further the analysis provides evidence that the emission from both poles is equal. We determine an angle of 20 deg between the rotation axis and the local magnetic axis. One pole has an offset of 5 deg from the antipodal position of the other pole. The beam pattern shows structures that can be interpreted as pencil- and fan-beam configurations. Since no assumptions on the polar emission are made, the results can be compared with various emission models. A comparison of results obtained from pulse profiles of different phases of the 35-day cycle indicates different attenuation of the radiation from the poles being responsible for the change of the pulse shape during the main-on state. These results also suggest the resolution of an ambiguity within a previous analysis of pulse profiles of Cen X-3, leading to a unique result for the beam pattern of this pulsar as well. The analysis of pulse profiles of the short-on state indicates that a large fraction of the radiation cannot be attributed to the direct emission from the poles. We give a consistent explanation of both the evolution of the pulse profile and the spectral changes with the 35-day cycle in terms of a warped precessing accretion disk.
Trefoil factor family domain peptides in the human respiratory tract
2000-02-01

Trefoil factor family domain peptides (TFF) are thought to be involved in mucosal epithelial restitution and wound healing of the gastrointestinal tract and are up-regulated in ulceration and in a variety of solid tumours. It was hypothesized that TFFs are also expressed on mucosal surfaces of the human respiratory tract. Lung tissue, nasal polyps, and sputum samples from seven patients with cystic fibrosis (CF), two with chronic and acute bronchitis, and non-dysplastic material from two cases of bronchial adenocarcinoma were analysed for TFF expression by immunohistochemistry, immunofluorescence, western blot and RT-PCR. Expression of TFF1 and TFF3 was observed in material from all patients. TFFs were localized in goblet and ciliated cells, as well as in some submucosal cells of tracheobronchial tissues and nasal polyps from normal and CF individuals. In sputa of patients with CF and with chronic or acute bronchitis, TFF1 and TFF3 were detected by western blotting. Freshly cultivated nasal epithelial cells transcribed and secreted TFFs and mucins, whereas nasal cells cultivated for 6 weeks still expressed mucins, but not TFFs. Secreted TFFs and mucins also bound to the surface of Staphylococcus aureus in infected CF airways. In conclusion, TFF1 and TFF3 are expressed and secreted in normal and inflamed airways. The association of TFFs with bacteria may contribute to the anti-microbial mucociliary defence system.
Robotics and Allied Technologies in Endoscopic Surgery
2000-02-01

Endoscopic surgery was developed in the 1970s and 1980s, with initial work conducted by pioneering surgeons. After the development of laparoscopic cholecystectomy, the breakthrough of endoscopic surgery had a great effect on all surgical specialties. Starting with rather simple procedures, such as cholecystectomy, a rapid progression toward more complex procedures, such as reflux or colonic surgery, took place. It was realized at this time that the existing endoscopic instruments allowed only a limited preciseness when performing the procedures, and part of the information from inside the abdominal cavity was not available to the surgeon. This prompted a discussion with engineers concerning the development of more advanced technologies to give those performing endoscopic surgery the same quality of information and manipulation that surgeons have when performing open surgery. These qualities include (1) instruments and manipulators that allow surgical action under endoscopic control with all degrees of freedom; (2) devices that provide surgeons with tactile feedback; and (3) vision systems that provide surgeons with the same quality of visual information as with open surgery, namely, high resolution, excellent color quality, precise spatial information, and a constant clear view for optimal surgical action. At the end of 1999, some of the aforementioned quality concepts found their way into the surgical routine, but most of the concepts are still being developed. Another decade will pass before endoscopic surgery procedures will be closer to the technological goals.
Magnetic resonance imaging guided corticosteroid injection of the sacroiliac joints in patients with therapy resistant spondyloarthropathy: a pilot study.
2000-02-01

MRI guided corticosteroid injection of SI joints appears to be an effective and safe procedure without exposure to radiation. It is a useful therapeutic modality, especially in young patients with severe isolated sacroiliitis.
Disseminated fatal human cytomegalovirus disease after severe trauma
2000-02-01

The lack of specific clinical symptoms of HCMV disease and the delay until viral culture results are available make an exact and timely diagnosis of HCMV disease difficult. Its prevalence in critically ill but otherwise not immunosuppressed patients is currently unknown and possibly underestimated. Because severe illness or trauma can cause immunodysfunction and, thus, may contribute to an increased rate of HCMV disease, detailed studies are warranted to evaluate the real risk in the ICU setting.