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Whether the Coordinate Structure Constraint (CSC) (Ross, 1967) is a syntactic constraint has been discussed much in the literature. This paper reconsiders this issue by drawing on evidence from Japanese and Korean. Our examination of the CSC patterns in relative clauses in the two languages reveals that a pragmatically-based approach along the lines of Kehler (2002) predicts the relevant empirical patterns straightforwardly whereas alternative syntactic approaches run into many problems. We take these results to provide strong support for the view that the CSC is a pragmatic principle rather than a syntactic constraint.
This paper deals with Korean postpositions. They are treated as suffixes in recent lexicalist works. But they differ syntactically from suffixes and we will propose to treat them as clitics, i.e. words combining with a phrase in the syntax and attaching to its last lexical item in the phonology. We treat them as weak syntactic heads, taking into account their head properties and the syntactic similarity between the mother phrase and the host phrase. They take the latter as complement and share most of its syntactic properties. Revising the traditional classification, we divide postpositions into three subtypes: marking, oblique and semantic postpositions, based on their distributional properties, such as optionality, non-nominal marking and stacking, etc. Finally we show how our analysis can be described in the HPSG model.
Preposition-noun combinations (PNCs) are compositional and productive, but not fully regular. In school grammars and many theoretical approaches, PNCs are neglected, but they have recently been addressed in an HPSG analysis by Baldwin et al. (2006). After discussing some basic properties of PNCs, we show that statistical methods can be employed to prove that PNCs are indeed productive and compositional, which again implies that PNCs should receive a syntactic analysis. Such an analysis, however, is impeded by the limited regularity of the construction. We will point out why adding semantic conditions to syntactic schemata might be necessary but not sufficient and turn then to a framework which allows the derivation of syntactic (and semantic) generalizations from linguistic data without taking recourse to introspective judgments.
Coordination in Japanese poses various puzzles which defy the standard notion of syntactic category. On the one hand, one can conjoin structures which one usually would not expect to form any constituent, and on the other hand, there are various conjunction particles that are sensitive to the kind of conjuncts that they combine with. In this paper we argue against abandoning the usual notion of constituency, and redefining the entire grammar of Japanese. We provide a novel construction-based account of the data in which the phenomena result from the interaction of the coordination construction, ellipsis, and allomorphy of the conjunction particle.
Verbs are the centerpiece of the sentence, and understanding of verb meanings is essential for language acquisition. Yet verb learning is said to be more challenging than noun learning for young children for several reasons. First, while nouns tend to denote concrete objects, which are perceptually stable over time, verbs tend to refer to action events, which are temporally ephemeral, and the beginning and the end of the action referred to by the verb are not clearly specified. Second, a verb takes nouns as arguments, and the meaning of a verb is determined as the relation between the arguments. To infer the meaning of a verb, children need to attend to the relation between the objects in the event rather than the objects themselves. In so doing, children make use of a variety of cues such as argument structure, meta-knowledge of the lexicon, and extra-linguistic contextual cues. In this paper, I present two lines of my recent research concerning young children's novel verb learning. Specifically, I first report a cross-linguistic study (Imai et al., 2008) examining how Japanese-, English-, and Chinese-speaking children utilize structural and non-structural, extra-linguistic cues when inferring novel verb meanings. Second, I present another study examining how young children utilize sound-meaning correlates (sound symbolism) in their inference of novel verb meanings. In the end, I evaluate the relative importance of structural cues among different cues children use in verb learning.
This paper presents a constraint-based account of verb form alternations (Short and Long Forms) in Mauritian which, basically, is syntactically driven: Short Forms appear with Canonical complements while Long Forms are expected with no realized complements. However, in specific contexts, Long Forms are unexpectedly authorized in declaratives with canonical complements and expresses Verum Focus.
Transparent heads
(2008)
Head-complement structures in HPSG identify most properties of the phrase with those of the head daughter, except for that valence property (e.g. SUBCAT or COMPS) whose constraints are met by the non-head daughter(s) in the phrase. In this paper I present several phenomena in English syntax where idiosyncratic properties of a non-head daughter in a phrase must remain visible on the phrasal node, in order to preserve the strong version of the principle of locality in subcategorization. I propose a general formal mechanism to effect this occasional transparency of heads with respect to certain properties of their complements.
This paper describes a number of verbal argument marking patterns found in the world's languages and provides HPSG analyses for them. In addition to commonly-occurring variations of morphosyntactic alignment (e.g. nominative-accusative, ergative-absolutive), this paper also presents analyses of more complex phenomena, including ergativity splits, Austronesian-style focus-case systems, and direct-inverse systems and their interaction with case.
Direct quotation raises three major problems for grammatical modelling: (i) the variety of quoted material (which can be a non linguistic behavior, or a sign in a different language), (ii) the embedding of an utterance inside another one, (iii) a special denotation, the content of the quotation being the utterance itself. We propose a unary rule, which turns the quoted material into a linguistic sign whose content is itself a behavior, which entertains a resemblance relation to the behavior demonstrated by the speaker. Syntactically, direct quotation comes in two varieties: it can be the complement of a quotative verb, or constitutes a head sentence, modified by an adjunct containing a quotative verb whose complement is extracted and identified with its local features.
In this paper we address the question of which transitive verbs allow there-insertion in Danish. We propose that two constraints have to be met in order for verbs to appear in Danish there-constructions. Firstly, as have been noted by others, an empty direct object position must be available. This constraint is not sufficient for restricting the set of verbs in there-constructions. We further propose a locative constraint. The transitive verbs allowing there-insertion will be shown to coincide with verbs that allow a locative analysis.
The information-structural status of clitic left dislocated arguments in Spanish has been argued to depend crucially on their thematic role. Earlier HPSG analyses of related phenomena in other languages do not take into account this sort of information. A formalization will be presented which can handle differences in information-structure arising from different thematic roles of clitic left dislocated phrases.
This paper examines the syntactic behaviour of two omnisyndetic coordinations (also called correlative coordinations), i.e. the disjunctive and the conjunctive types in Romanian, by explaining its data in a Romance perspective. Major issue has been whether these structures have symmetric or asymmetric structures. If all these Romance languages share a symmetric analysis for the disjunctive type Conj ... Conj, it is not the case for the conjunctive type. Our aim is to show that the postulation of a conjunctional status for the Romanian structure şi ... şi ('both ... and'), which is the most widespread view in Romanian grammars, is inadequate for the Romanian data.
The word order facts of radically non-configurational languages pose a challenge to HPSG approaches which assume both that the surface order of words is the yield of the (tectogrammatical) tree and standard HPSG-style cancellation of valence lists. These languages allow discontinuous noun phrases, in which modifiers appear separated from their head nouns by arbitrarily many other words from the same clause. In this paper, I explore an analysis which preserves tectogrammatical-phenogrammatical equivalence, and accounts for the word order facts of Wambaya with an analysis based on non-cancellation. This analysis is contrasted with other approaches to discontinuous constituents and analyses of other phenomena based on non-cancellation. Finally, I explore the implications for current models of semantic compositionality.
Non-restrictive relative clauses (NRRCs) can modify constituents which undergo 'pragmatic enrichment' when they appear in answers to questions. For example, in an interchange like: 'A: What did Jo think? B: That you should say nothing, which is surprising.' What B says is surprising is that 'Jo thinks ...' On the face of it, this might seem problematic for approaches to NRRCs which assume 'syntactic integration' and to support an 'orphan' analysis, where NRRCs are combined with purely conceptual representations. In this paper we examine a range of elliptical and anaphoric phenomena, and show that this conclusion is misplaced. In fact, the phenomena argue strongly in favour of a syntactically integrated analysis.
We contrast two types of sentences with a preposed NP in French in a construction based HPSG grammar. They differ with respect to different grammatical aspects (syntax, semantics, pragmatics and phonology), which cluster uniquely into constructions. Both are colloquial, a reason why they have been recognized only recently (see Zribi-Hertz 1986, 1996, Sabio 1995, 2006). Accordingly, we rely for the data on spoken corpora (Corpaix, CFRP) as well as on our intuitions. Both constructions involve a partitioned semantics but this mode of composition is associated with different effects. One construction is characterized semantically: the preposed NP is the theme of a categorical proposition. The other construction is characterized pragmatically: it is associated with an independent declarative clause, a typical use of which is to signal a break in the interaction.
Jeanne d'Arc im Kino
(2008)
While in large clinical laboratories the implementation of total laboratory automation is continuously proceeding, this concept is mostly not suitable for small- and middle-sized laboratories or for testing laboratories of blood donation services due to costs and required space. For these facilities, however, a rational level of automation can be achieved by the installation of stand-alone work cells for pre-analytical and selected analytical processes. In this review, the features of some automated pre-analytical sample processing systems and automated systems for the serological testing for infectious diseases are described exemplarily and compared with each other. The major advantages of automated systems, compared to a solely manual workflow, are described. Essential factors which have to be considered for making the choice for an appropriate automated system are pointed out.
Hereditary dysfibrinogenemia is a rare clotting disorder due to a structural defect in the fibrinogen molecule that results in a tendency for bleeding and thrombosis, as well as obstetric complications. We describe the laboratory results and clinical manifestations for 50 patients with a diagnosis of dysfibrinogenemia. Various different laboratory measurements of fibrinogen were performed on samples from these patients, including fibrinogen (Clauss), heat fibrinogen precipitation according to Schulz and immunological fibrinogen. Fifty patients were found with dysfibrinogenemia (52% female; median age 52, range 9–89 years). The fibrinogen level according to Clauss was low, with a median of 51 mg/dL (range 15–86 mg/dL; normal range 150–450 mg/dL). Determination of other fibrinogen levels revealed normal results: heat fibrinogen precipitation according to Schulz, 240 mg/dL; and immunological fibrinogen, 244 mg/dL. The median reptilase time was longer than normal, at 55 s (normal 20 s). Some 50% of the patients reported a distinct bleeding tendency, mostly a tendency for hematoma (60%) and secondary bleeding (44%). Thirteen patients had thrombotic events, of which 54% were located arterially. Some 12% of the patients reported a tendency for bleeding and for thrombosis, whereas 19% had miscarriages, sometimes recurrent. We found that functional fibrinogen levels (Clauss) were generally lower in patients with bleeding manifestations (43 vs. 57 mg/dL in other patients).
Varicella zoster virus (VZV) belongs to one of the eight herpes viruses known to infect humans. While primary VZV infection (chickenpox) is generally a disease of childhood, herpes zoster occurs primarily in elderly persons (>50 years). Herpes zoster, also called shingles, is a neurocutaneous disease resulting from reactivation of latent VZV infection within dorsal root ganglia. Severe complications may occur in elderly persons and immunocompromised of any age, including severe complication of the eye, ear, skin and internal organs, and the peripheral and central nervous systems. A progressive decline of VZV-specific cell-mediated immunity and age are associated with an increased incidence and severity of herpes zoster and postherpetic neuralgia (PHN). PHN is the most common complication of herpes zoster causing chronic, debilitating pain. In cases with characteristic signs and symptoms (presence of prodromal pain, eruptions, grouped vesicles, segmental pain), the diagnosis is almost distinctive enough and no laboratory investigations are required. However, for patients lacking no characteristic pathology, a rapid laboratory diagnosis may be helpful to begin antiviral therapy as soon as possible. Antiviral therapy should be initiated immediately within 72 h after rash onset, particularly in older patients. The main aim of treatment is to control and reduce acute zoster pain, shorten virus replication, avoid dissemination of skin lesions and prevent PHN and other severe complications. The aim of the present review is to outline advantages and disadvantages of different herpes zoster laboratory methods (microscopy, direct immunofluorescence assay, detection of viral DNA, virus isolation and serological methods). A live attenuated VZV vaccine has been developed to prevent herpes zoster and PHN in individuals >60 years of age (Shingles Prevention Study). This review summarises the epidemiology, pathogenesis, clinical aspects, complications, therapy and prevention of varicella zoster.
Das Varizella-Zoster-Virus (VZV) gehört zu einem der acht bisher bekannten humanpathogenen Herpesviren.
Während Windpocken (Primärinfektion) eine typische Erkrankung im Kindes- und Jugendalter sind, tritt der Zoster (endogene Reaktivierung) gehäuft bei älteren Menschen jenseits des fünften Lebensjahrzehnts auf. Der Zoster, auch Gürtelrose genannt, ist eine neurokutane Entzündungskrankheit, die als endogene Reaktivierung der latent in den (Hinterwurzel-) Ganglienzellen persistierenden Varizella-Zoster-Viren definiert ist.
Ernsthafte Komplikationen, die im Zusammenhang mit dem Zoster beschrieben werden, treten vor allem bei älteren und immunsupprimierten Patienten auf. Diese können sich an Haut, Auge, Ohr, an verschiedenen inneren Organen sowie am zentralen und peripheren Nervensystem manifestieren. Ein fortschreitendes Nachlassen der VZV-spezifischen zellvermittelten Immunität ist mit dem Alter assoziiert, ebenso wie der gleichzeitige Anstieg von Inzidenz und Schweregrad einer Zosterinfektion sowie das Auftreten einer postzosterischen Neuralgie (PZN).
Die postzosterische Neuralgie (PZN), die einen chronischen Schmerzzustand beschreibt, stellt die häufigste Komplikation des Zosters dar. Im Fall einer eindeutigen klinischen Situation (Prodromalschmerzen, charakteristische Hauteffloreszenzen (Eruptionen, Bläschen), dermatomabhängige Schmerzen) werden keine laboratoriumsdiagnostischen Nachweisverfahren benötigt. Aber gerade bei Patienten, die keine „Zoster-typische Klinik“ aufzeigen, kann eine schnelle Diagnosesicherung durch verschiedene Nachweismethoden hilfreich sein, um schnellstmöglich eine antivirale Therapie einzuleiten. Es wird empfohlen, diese so früh wie möglich, d.h. innerhalb von 72 Stunden nach Auftreten der ersten Effloreszenzen, zu beginnen. Das Hauptziel der Therapie sollte die Kontrolle und Reduktion des akuten Zosterschmerzes, die verkürzte Virusreplikation, die Verhinderung der Ausbreitung der Hautläsionen sowie die Prävention der postzosterischen Neuralgie und weiterer ernsthafter Komplikationen sein. In der vorliegenden Arbeit werden Vor- und Nachteile verschiedener Nachweisverfahren (Mikroskopie, Immunofluoreszenztechnik, DNA-Nachweisverfahren, Virusisolierung und Serologie) beschrieben. Eine attenuierte VZV-Lebendvakzine wurde entwickelt, um Herpes Zoster und die PZN bei über 60- jährigen zu verhindern (Shingles Prevention Study). Es wird ein Überblick über die Epidemiologie, Pathogenese, klinischen Aspekte, Komplikationen, therapeutischen Möglichkeiten sowie die Prävention eines Herpes Zoster gegeben.
Einleitung: Medizinisches Personal ist dem Risiko ausgesetzt, sich an kontaminierten Instrumenten zu verletzen. Nadelstichverletzungen (NSV) können zu ernsthaften und möglicherweise schwerwiegenden Infektionen wie Hepatitis B (HBV), Hepatitis C (HCV) und HIV-Infektionen führen. Dieses Risiko betrifft auch Medizinstudenten im Verlaufe ihrer klinischen Ausbildung. Jede NSV sollte als Arbeitsunfall gemeldet werden, damit postexpositionelle Maßnahmen eingeleitet sowie etwaige Infektionen frühzeitzeitig erkannt und behandelt werden können. Im Falle einer Infektion können versicherungsrechtliche Ansprüche gegenüber den Berufsgenossenschaften geltend gemacht werden. Ziel unserer Studie war die Erhebung der Häufigkeit und Melderate von NSV bei Medizinstudenten.
Methoden: Anonyme Fragebogenerhebung bei Medizinstudenten vor Beginn des Praktischen Jahres.
Ergebnisse: Von den befragten Studenten gaben 58,8% (n=183/311) mindestens eine NSV im Rahmen des Studiums an. Insgesamt 284 NSV wurden von den befragten Studenten gemeldet. Lediglich 38,3% der Studenten hatten alle NSV gemeldet. Die häufigste Ursache für das Nichtmelden der NSV war Schamgefühl aufgrund der Verletzung (54,0%).
Schlussfolgerungen: Expositionen gegenüber Blut sind eine häufige und ernstzunehmende Gefährdung von Medizinstudenten. Es sollten Maßnahmen ergriffen werden, um die Häufigkeit von NSV zu reduzieren und das Meldeverhalten der Studenten zu optimieren. Entsprechende Schulungen sollten sowohl die technischen Fertigkeiten der Studenten als auch das Bewusstsein über die Gefährdung durch NSV vermitteln.
Introduction: Healthcare workers (HCWs) are exposed to bloodborne pathogens (e.g., contaminated devices). In the healthcare environment, needlestick injuries (NSI) represent a major risk factor in the transmission of hepatitis B virus (HBV), hepatitis C virus (HCV), and human immunodeficiency virus (HIV). Medical students are at risk of occupational exposure to bloodborne viruses following needlestick injuries during medical education. Reporting of needlestick injuries is an important step for initiating early prophylaxis or treatment. In the case of a bloodborne infection, pursuant to insure law could result in a claim. The objective of the present study was to describe occupational blood exposure of medical students through needlestick injuries.
Methods: Sixth-year medical students were invited to complete an anonymous questionnaire.
Results: In our study, 58.8% (n=183/311) of medical students recalled at least one needlestick injury during their studies. Overall, 284 needlestick injuries were reported. Only 38.3% of medical students reported all NSI to the appropriate hospital personnel. The main reason (54.0%) for not reporting NSI was being ashamed of having an NSI.
Conclusions: Occupational exposure to blood is a common problem among medical students. Efforts are required to ensure greater awareness among medical students about the risk of bloodborne pathogens. Proper training in procedures and how to act in case of injury should be offered to reduce the number of needlestick injuries.
Human serum albumin (HSA) nanoparticles represent a promising tool for targeted drug delivery to tumor cells. The coupling of the antibody trastuzumab to nanoparticles uses the capability of human epidermal growth factor receptor 2 (HER2)-positive cells to incorporate agents linked to HER2. In our present study, we developed targeted nanoparticles loaded with antisense oligonucleotides (ASOs) against polo-like kinase 1 (Plk1). We evaluated the receptor-mediated uptake into HER2-positive and -negative breast cancer and murine cell lines. We performed quantitative real-time PCR and Western blot analyses to monitor the impact on Plk1 expression in HER2-positive breast cancer cells. Antibody-conjugated nanoparticles showed a specific targeting to HER2-overexpressing cells with cellular uptake by receptor-mediated endocytosis and a release into HER2-positive BT-474 cells. We observed a significant reduction of Plk1 mRNA and protein expression and increased activation of Caspase 3/7. Thus, this is the first report about ASO-loaded HSA nanoparticles, where an impact on gene expression could be observed. The data provide the basis for the further development of carrier systems for Plk1-specific ASOs to reduce off-target effects evoked by systemically administered ASOs and to achieve a better penetration into primary and metastatic target cells. Treatment of tumors using trastuzumab-conjugated ASO-loaded HSA nanoparticles could be a promising approach to reach this goal.
GTPase-activating proteins are required to terminate signaling by Rap1, a small guanine nucleotide-binding protein that controls integrin activity and cell adhesion. Recently, we identified Rap1GAP2, a GTPase-activating protein of Rap1 in platelets. Here we show that 14-3-3 proteins interact with phosphorylated serine 9 at the N terminus of Rap1GAP2. Platelet activation by ADP and thrombin enhances serine 9 phosphorylation and increases 14-3-3 binding to endogenous Rap1GAP2. Conversely, inhibition of platelets by endothelium-derived factors nitric oxide and prostacyclin disrupts 14-3-3 binding. These effects are mediated by cGMP- and cAMP-dependent protein kinases that phosphorylate Rap1GAP2 at serine 7, adjacent to the 14-3-3 binding site. 14-3-3 binding does not change the GTPase-activating function of Rap1GAP2 in vitro. However, 14-3-3 binding attenuates Rap1GAP2 mediated inhibition of cell adhesion. Our findings define a novel crossover point of activatory and inhibitory signaling pathways in platelets.
Type I interferons (IFNs) signal for their diverse biological effects by binding a common receptor on target cells, composed of the two transmembrane IFNAR1 and IFNAR2 proteins. We have previously differentially enhanced the antiproliferative activity of IFN by increasing the weak binding affinity of IFN to IFNAR1. In this study, we further explored the affinity interdependencies between the two receptor subunits and the role of IFNAR1 in differential IFN activity. For this purpose, we generated a panel of mutations targeting the IFNAR2 binding site on the background of the IFNalpha2 YNS mutant, which increases the affinity to IFNAR1 by 60-fold, resulting in IFNAR2-to-IFNAR1 binding affinity ratios ranging from 1000:1 to 1:1000. Both the antiproliferative and antiviral potencies of the interferon mutants clearly correlated to the in situ binding IC(50) values, independently of the relative contributions of the individual receptors, thus relating to the integral lifetime of the complex. However, the antiproliferative potency correlated throughout the entire range of affinities, as well as with prolonged IFNAR1 receptor down-regulation, whereas the antiviral potency reached a maximum at binding affinities equivalent to that of wild-type IFNalpha2. Our data suggest that (i) the specific activity of interferon is related to the ternary complex binding affinity and not to affinity toward individual receptor components and (ii) although the antiviral pathway is strongly dependent on pSTAT1 activity, the cytostatic effect requires additional mechanisms that may involve IFNAR1 down-regulation. This differential interferon response is ultimately mediated through distinct gene expression profiling.
The neuronal adaptor protein Fe65 is involved in brain development, Alzheimer disease amyloid precursor protein (APP) signaling, and proteolytic processing of APP. It contains three protein-protein interaction domains, one WW domain, and a unique tandem array of phosphotyrosine-binding (PTB) domains. The N-terminal PTB domain (Fe65-PTB1) was shown to interact with a variety of proteins, including the low density lipoprotein receptor-related protein (LRP-1), the ApoEr2 receptor, and the histone acetyltransferase Tip60. We have determined the crystal structures of human Fe65-PTB1 in its apo- and in a phosphate-bound form at 2.2 and 2.7A resolution, respectively. The overall fold shows a PTB-typical pleckstrin homology domain superfold. Although Fe65-PTB1 has been classified on an evolutionary basis as a Dab-like PTB domain, it contains attributes of other PTB domain subfamilies. The phosphotyrosine-binding pocket resembles IRS-like PTB domains, and the bound phosphate occupies the binding site of the phosphotyrosine (Tyr(P)) within the canonical NPXpY recognition motif. In addition Fe65-PTB1 contains a loop insertion between helix alpha2 and strand beta2(alpha2/beta2 loop) similar to members of the Shc-like PTB domain subfamily. The structural comparison with the Dab1-PTB domain reveals a putative phospholipid-binding site opposite the peptide binding pocket. We suggest Fe65-PTB1 to interact with its target proteins involved in translocation and signaling of APP in a phosphorylation-dependent manner.
Precursor protein translocation across the outer chloroplast membrane depends on the action of the Toc complex, containing GTPases as recognizing receptor components. The G domains of the GTPases are known to dimerize. In the dimeric conformation an arginine contacts the phosphate moieties of bound nucleotide in trans. Kinetic studies suggested that the arginine in itself does not act as an arginine finger of a reciprocal GTPase-activating protein (GAP). Here we investigate the specific function of the residue in two GTPase homologues. Arginine to alanine replacement variants have significantly reduced affinities for dimerization compared with wild-type GTPases. The amino acid exchange does not impact on the overall fold and nucleotide binding, as seen in the monomeric x-ray crystallographic structure of the Arabidopsis Toc33 arginine-alanine replacement variant at 2.0A. We probed the catalytic center with the transition state analogue GDP/AlF(x) using NMR and analytical ultracentrifugation. AlF(x) binding depends on the arginine, suggesting the residue can play a role in catalysis despite the non-GAP nature of the homodimer. Two non-exclusive functional models are discussed: 1) the coGAP hypothesis, in which an additional factor activates the GTPase in homodimeric form; and 2) the switch hypothesis, in which a protein, presumably the large Toc159 GTPase, exchanges with one of the homodimeric subunits, leading to activation.
Treatment predictors are important tools for the management of therapy in patients with chronic hepatitis B and C virus (HBV, HCV) infection. In chronic hepatitis B, several pretreatment parameters have been identified for prediction of virologic response to interferon alfa-based antiviral therapies or treatment with polymerase inhibitors. In interferon alfa and pegylated interferon alfa-treated patients, low baseline HBV DNA concentrations, HBV genotype A (B), and high baseline ALT levels are significantly associated with treatment response. In patients treated with nucleos(t)ide analogues, low baseline HBV DNA but not viral genotype is positively associated with virologic response. During treatment the best predictor of response is HBV DNA kinetics. Early viral suppression is associated with favourable virologic response and reduced risk for subsequent resistance mutations. For the current standard treatment with pegylated interferon alfa and ribavirin in patients with chronic hepatitis C, infection with HCV genotypes 2 and 3, baseline viral load below 400,000–800,000 IU/ml, Asian and Caucasian ethnicity, younger age, low GGT levels, absence of advanced fibrosis/cirrhosis, and absence of steatosis in the liver have been identified as independent pretreatment predictors of a sustained virologic response. After initiation of treatment, initial viral decline with undetectable HCV-RNA at week 4 of therapy (RVR) is the best predictor of sustained virologic response independent of HCV genotype.
Aufgrund der leichten Handhabung und des Nachweises einer Mortalitätssenkung gilt der Nachweis von okkultem Blut (FOBT) im Stuhl derzeit als das am weitesten verbreitete Screeningverfahren für das kolorektale Karzinom. Als nachteilig erweisen sich allerdings eine unzureichende Sensitivität, insbesondere beim Nachweis früher Stadien und eine nach wie vor geringe Akzeptanz in der Bevölkerung. Vorläufige Daten zum Nachweis von Calprotectin oder der Tumor-M2-PK im Stuhl ließen bessere Screeningeigenschaften erwarten. Aber auch hierschränkt die geringe Sensitivität für frühe Vorstufen und unzureichende Spezifität mit zu erwartenden hohen Folgekosten die Tauglichkeit der Tests deutlich ein. Die kürzlich entwickelten immunologischen FOBTs (I-FOBT)erweisen sich als spezifischer und sensitiver. Sie beruhen auf dem Nachweis von humanem Hämoglobin mittels spezifischer Antikörper und sind somit unabhängig von diätetischen oder medikamentösen Faktoren, was zu einer deutlich besseren Akzeptanz führt. Sie gelten derzeit als kosteneffektivste Verfahren unter den nichtinvasiven Screeningmaßnahmen. Der Nachweis von Tumor-DNA im Stuhl eröffnet eine neue Ära zum frühzeitigen Nachweis kolorektaler Karzinome. Erste kleinere Studien weisen auf eine sehr gute Sensitivität dieser Verfahren hin. Sie lagen für kolorektale Karzinome zwischen 62–91% und für Adenome zwischen 26–73% bei mit 93–100% sehr guter Spezifität. Als nachteilig im Ver-gleich zu den derzeit verfügbaren Screeningtests erweisen sich allerdings die vergleichsweise hohen Kosten.
Given the simplicity of the method and how it can be applied, as well as proof that it lowers the mortality rate, fecal occult blood testing (FOBT) is currently the most commonly used screening method for colorectal cancer (CRC). However, the test suffers from poor sensitivity, particularly with respect to detecting early stages, as well as low acceptance among the population. Preliminary data on detecting calprotectin and tumour-M2-PK in the stool indicated that a better screening performance could be expected. But these tests also suffer from low sensitivity in detecting early stages and from poor specificity, thus limiting the usefulness of the tests as a result of high follow-up costs. Recently developed immunological tests (I-FOBT) demonstrate significantly increased sensitivity and specificity. I-FOBTs use antibodies specific to human hemoglobin and are therefore not affected by diet and drugs, leading to improved patient partipication. At present, I-FOBTs seem to be the most cost-effective approach for non-invasive screening. The detection of tumour-DNA in the stool opens up a new era in early diagnosis of colorectal cancer. Small trials have pointed to a very high sensitivity of these methods: 62–91% for colorectal cancer and between 26% and 73% for adenomas, with a very high level of specificity (93–100%). The major drawback of this type of testing, compared with other screening tests available today, is its high cost.
Requirements for the interaction of mouse Polkappa with ubiquitin and its biological significance
(2008)
Polkappa protein is a eukaryotic member of the DinB/Polkappa branch of the Y-family DNA polymerases, which are involved in the tolerance of DNA damage by replicative bypass. Despite universal conservation through evolution, the precise role(s) of Polkappa in this process has remained unknown. Here we report that mouse Polkappa can physically interact with ubiquitin by yeast two-hybrid screening, glutathione S-transferase pulldown, and immunoprecipitation methods. The association of Polkappa with ubiquitin requires the ubiquitin-binding motifs located at the C terminus of Polkappa. In addition, Polkappa binds with monoubiquitinated proliferating cell nuclear antigen (PCNA) more robustly than with non-ubiquitinated PCNA. The ubiquitin-binding motifs mediate the enhanced association between monoubiquitinated PCNA and Polkappa. The ubiquitin-binding motifs are also required for Polkappa to form nuclear foci after UV radiation. However, the ubiquitin-binding motifs do not affect Polkappa half-life. Finally, we have examined levels of Polkappa expression following the exposure of mouse cells to benzo[a]pyrene-dihydrodiol epoxide or UVB radiation.
Glucokinase (GK) is a key enzyme of glucose metabolism in liver and pancreatic beta-cells, and small molecule activators of GK (GKAs) are under evaluation for the treatment of type 2 diabetes. In liver, GK activity is controlled by the GK regulatory protein (GKRP), which forms an inhibitory complex with the enzyme. Here, we performed isothermal titration calorimetry and surface plasmon resonance experiments to characterize GK-GKRP binding and to study the influence that physiological and pharmacological effectors of GK have on the protein-protein interaction. In the presence of fructose-6-phosphate, GK-GKRP complex formation displayed a strong entropic driving force opposed by a large positive enthalpy; a negative change in heat capacity was observed (Kd = 45 nm, DeltaH = 15.6 kcal/mol, TDeltaS = 25.7 kcal/mol, DeltaCp = -354 cal mol(-1) K(-1)). With k(off) = 1.3 x 10(-2) s(-1), the complex dissociated quickly. The thermodynamic profile suggested a largely hydrophobic interaction. In addition, effects of pH and buffer demonstrated the coupled uptake of one proton and indicated an ionic contribution to binding. Glucose decreased the binding affinity between GK and GKRP. This decrease was potentiated by an ATP analogue. Prototypical GKAs of the amino-heteroaryl-amide type bound to GK in a glucose-dependent manner and impaired the association of GK with GKRP. This mechanism might contribute to the antidiabetic effects of GKAs.
Cytotoxic T lymphocytes eliminate infected cells upon surface display of antigenic peptides on major histocompatibility complex I molecules. To promote immune evasion, UL49.5 of several varicelloviruses interferes with the pathway of major histocompatibility complex I antigen processing. However, the inhibition mechanism has not been elucidated yet. Within the macromolecular peptide-loading complex we identified the transporter associated with antigen processing (TAP1 and TAP2) as the prime target of UL49.5. Moreover, we determined the active oligomeric state and crucial elements of the viral factor. Remarkably, the last two residues of the cytosolic tail of UL49.5 are essential for endoplasmic reticulum (ER)-associated proteasomal degradation of TAP. However, this process strictly requires additional signaling of an upstream regulatory element in the ER lumenal domain of UL49.5. Within this new immune evasion mechanism, we show for the first time that additive elements of a small viral factor and their signaling across the ER membrane are essential for targeted degradation of a multi-subunit membrane complex.
We disassembled monomeric and dimeric yeast ATP synthase under mild conditions to identify labile proteins and transiently stable subcomplexes that had not been observed before. Specific removal of subunits α, β, oligomycin sensitivity conferring protein (OSCP), and h disrupted the ATP synthase at the γ-α3β3 rotor-stator interface. Loss of two F1-parts from dimeric ATP synthase led to the isolation of a dimeric subcomplex containing membrane and peripheral stalk proteins thus identifying the membrane/peripheral stalk sectors immediately as the dimerizing parts of ATP synthase. Almost all subunit a was found associated with a ring of 10 c-subunits in two-dimensional blue native/SDS gels. We therefore postulate that c10a1-complex is a stable structure in resting ATP synthase until the entry of protons induces a breaking of interactions and stepwise rotation of the c-ring relative to the a-subunit in the catalytic mechanism. Dimeric subunit a was identified in SDS gels in association with two c10-rings suggesting that a c10a2c10-complex may constitute an important part of the monomer-monomer interface in dimeric ATP synthase that seems to be further tightened by subunits b, i, e, g, and h. In contrast to the monomer-monomer interface, the interface between dimers in higher oligomeric structures remains largely unknown. However, we could show that the natural inhibitor protein Inh1 is not required for oligomerization.
Location and orientation of serotonin receptor 1a agonists in model and complex lipid membranes
(2008)
Magic angle spinning (MAS) NMR has been used to investigate the location and orientation of five serotonin receptor 1a agonists (serotonin, buspirone, quipazine, 8-OH-DPAT, and LY-163,165) in single component model lipid and brain lipid membranes. The agonist locations are probed by monitoring changes in the lipid proton chemical shifts and by MAS-assisted nuclear Overhauser enhancement spectroscopy, which indicates the orientation of the agonists with respect to the 1,2-dioleoyl-sn-glycero-3-phosphocholine lipids. In the single component bilayer, the membrane agonists are found predominantly in the top of the hydrophobic chain or in the glycerol region of the membrane. Most of the agonists orient approximately parallel to the membrane plane, with the exception of quipazine, whose piperazine ring is found in the glycerol region, whereas its benzene ring is located within the lipid hydrophobic chain. The location of the agonist in brain lipid membranes is similar to the 1,2-dioleoyl-sn-glycero-3-phosphocholine lipid bilayers; however, many of the agonists appear to locate close to the cholesterol in the membrane in preference to the phospholipids.
The lysosomal ABC transporter associated with antigen processing-like (TAPL, ABCB9) acts as an ATP-dependent polypeptide transporter with broad length selectivity. To characterize in detail its substrate specificity, a procedure for functional reconstitution of human TAPL was developed. By intensive screening of detergents, ideal solubilization conditions were evolved with respect to efficiency, long term stability, and functionality of TAPL. TAPL was isolated in a two-step procedure with high purity and, subsequently, reconstituted into proteoliposomes. The peptide transport activity of reconstituted TAPL strongly depends on the lipid composition. With the help of combinatorial peptide libraries, the key positions of the peptides were localized to the N- and C-terminal residues with respect to peptide transport. At both ends, TAPL favors positively charged, aromatic, or hydrophobic residues and disfavors negatively charged residues as well as asparagine and methionine. Besides specific interactions of both terminal residues, electrostatic interactions are important, since peptides with positive net charge are more efficiently transported than negatively charged ones.
The thickness of the cerebral cortex can provide valuable information about normal and abnormal neuroanatomy. High resolution MRI together with powerful image processing techniques has made it possible to perform these measurements automatically over the whole brain. Here we present a method for automatically generating voxel-based cortical thickness (VBCT) maps. This technique results in maps where each voxel in the grey matter is assigned a thickness value. Sub-voxel measurements of thickness are possible using sub-sampling and interpolation of the image information. The method is applied to repeated MRI scans of a single subject from two MRI scanners to demonstrate its robustness and reproducibility. A simulated data set is used to show that small focal differences in thickness between two groups of subjects can be detected. We propose that the analysis of VBCT maps can provide results that are complementary to other anatomical analyses such as voxel-based morphometry.
We present a measurement of e+e− pair production in central PbAu collisions at 158A GeV/c. As reported earlier, a significant excess of the e+e− pair yield over the expectation from hadron decays is observed. The improved mass resolution of the present data set, recorded with the upgraded CERES experiment at the CERN-SPS, allows for a comparison of the data with different theoretical approaches. The data clearly favor a substantial in-medium broadening of the ρ spectral function over a density-dependent shift of the ρ pole mass. The in-medium broadening model implies that baryon induced interactions are the key mechanism to the observed modifications of the ρ meson at SPS energy.
Ribavirin in combination with peginterferon alfa shows strong clinical efficacy against chronic hepatitis C, and is now established as the standard of care. However, the precise role of ribavirin is still being defined, suggesting that optimal ribavirin dose should be maintained over the whole treatment period. Ribavirin dosage varies by bodyweight for genotype 1 disease (1000 mg/day in patients ⩽75 kg and 1200 mg/day in patients >75 kg), whereas 800 mg/day is sufficient to ensure optimal response in all genotype 2/3 patients. Similarly, genotype 1 patients benefit from 48 weeks of therapy, while 24 weeks is sufficient for genotype 2/3 disease.
Recent data suggest treatment success is dependent on cumulative ribavirin exposure, as patients who receive <60% of the planned dose have lower response rates, regardless of whether reductions are from temporary interruptions or premature cessation of therapy. All patients should be monitored for hemolytic anemia, as early diagnosis allows management through small dose reductions and stepwise return to the target dose, maximizing cumulative exposure. Despite these recent advances in our knowledge, many questions remain, such as whether the role of ribavirin will change or even be eliminated as new therapies are developed.
The extrapolation of results obtained on a series of 3 succeeding grids with halved mesh size is tested as a variant of the multigrid approach for solving the Laplace and Poisson equations in 2D. Based on corresponding experience with BEM for electric and magnetic [2] field problems a pure power law is applied instead of the famous Richardson extrapolation [3]. On those grid points, which are common to all 3 grids, the potential values are extrapolated to an arbitrary fine discretization. On the points of the finest grid in between those of the coarser ones the potentials then are obtained by only few iterations to perform the interpolation. Both, the common 5-point discretization and the famous 9-point discretization by E. Kasper [5] are investigated and compared with respect to the possible win of accuracy by extrapolation. As an interesting result of this kind of extrapolation, the accumulated local discretization errors of the 5-point discretization are partially cured and the high accuracy by the 9-point formula of Kasper makes extrapolation inefficient. Like for classical MG (multi grid) [6] the acceleration of potential calculations on grids of large size is substantial.
Mitochondrial complex I (NADH:ubiquinone oxidoreductase) undergoes reversible deactivation upon incubation at 30–37 °C. The active/deactive transition could play an important role in the regulation of complex I activity. It has been suggested recently that complex I may become modified by S-nitrosation under pathological conditions during hypoxia or when the nitric oxide:oxygen ratio increases. Apparently, a specific cysteine becomes accessible to chemical modification only in the deactive form of the enzyme. By selective fluorescence labeling and proteomic analysis, we have identified this residue as cysteine-39 of the mitochondrially encoded ND3 subunit of bovine heart mitochondria. Cysteine-39 is located in a loop connecting the first and second transmembrane helix of this highly hydrophobic subunit. We propose that this loop connects the ND3 subunit of the membrane arm with the PSST subunit of the peripheral arm of complex I, placing it in a region that is known to be critical for the catalytic mechanism of complex I. In fact, mutations in three positions of the loop were previously reported to cause Leigh syndrome with and without dystonia or progressive mitochondrial disease.
Dilepton production in pp and Au+Au nucleus–nucleus collisions at s=200GeV as well as in In+In and Pb+Au at 158AGeV is studied within the microscopic HSD transport approach. A comparison to the data from the PHENIX Collaboration at RHIC shows that standard in-medium effects of the ρ,ω vector mesons—compatible with the NA60 data for In+In at 158AGeV and the CERES data for Pb+Au at 158AGeV—do not explain the large enhancement observed in the invariant mass regime from 0.2 to 0.5 GeV in Au+Au collisions at s=200 GeV relative to pp collisions.
We explore the formation of diquark bound states and their Bose–Einstein condensation (BEC) in the phase diagram of three-flavor quark matter at nonzero temperature, T, and quark chemical potential, μ. Using a quark model with a four-fermion interaction, we identify diquark excitations as poles of the microscopically computed diquark propagator. The quark masses are obtained by solving a dynamical equation for the chiral condensate and are found to determine the stability of the diquark excitations. The stability of diquark excitations is investigated in the T–μ plane for different values of the diquark coupling strength. We find that diquark bound states appear at small quark chemical potentials and at intermediate coupling strengths. Bose–Einstein condensation of non-strange diquark states occurs when the attractive interaction between quarks is sufficiently strong.
We propose that the measurement of the transverse momentum dependence of the double ratio of the nuclear modification factors of charm and bottom jets, RAAc(pT)/RAAb(pT), in central nuclear collisions at the LHC will provide an especially robust observable that can be used to differentiate Standard Model perturbative QCD predictions from recently proposed strong coupling string drag models derived using the AdS/CFT conjecture.
Based on the microscopic transport model UrQMD in which hadronic and string degrees of freedom are employed, the HBT parameters in the longitudinal co-moving system are investigated for charged pion and kaon, and Λ sources in heavy ion collisions (HICs) at SPS and RHIC energies. In the Cascade mode, RO and the RL at high SPS and RHIC energies do not follow the mT-scaling, however, after considering a soft equation of state with momentum dependence (SM-EoS) for formed baryons and a density-dependent Skyrme-like potential for “pre-formed” particles, the HBT radii of pions and kaons and even those of Λs with large transverse momenta follow the mT-scaling function R=3/mT fairly well.