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Die Öffentlichkeit gilt als Kennzeichen demokratischer Vernunft und damit als ein zentrales normatives Qualitätsmerkmal der Demokratie. In ihrer modernen und empirisch weitestgehend unerforschten digitalen Variante (hier: Twitter) verdient sie besonderes Interesse. Der Beitrag untersucht erstmalig für Deutschland die Twitter-Kommunikation in einer Regierungsbildungsphase. Besonders interessant ist hierbei die kommunikative Rahmung durch einen bundesweit einmaligen SPD-Mitgliederentscheid zum Koalitionsvertrag. Medienwirksam wurde explizit eine Beteiligung der Bürger und besonders der SPD-Mitglieder angestrebt, die nicht nur klassisch „offline“, sondern gerade auch im Web 2.0 forciert wurde. Der Fall „GroKo“ zeigt: Die digitale Öffentlichkeit wird zur Arena der publikumswirksamen Legitimationsbeschaffung. Die klassischen Akteure der politischen Offline-Öffentlichkeit müssen sich nämlich neu positionieren. Akteure aus Politik und Verwaltung können sich beispielsweise als bürgernah zelebrieren, indem sie entsprechende Kommunikationsangebote initiieren, während Medienakteure vor der strategischen Frage stehen, das digitale Treiben zu beobachten, zu ignorieren oder zu forcieren. The public sphere is a key criterion in western democracies. In its digital version, it is of special interest, too. The microblogging service Twitter claims that it constitutes a new public sphere of political communication. Citizens are able to directly express their opinion on the topics that interest them. The actors of the offline political public sphere must thereby reconsider their communication strategy. Politicians and administration’s professionals can use Twitter as a citizen friendly communication service. They can simulate citizen’s friendly situations. Journalists are faced with the question how to deal with the new digital public sphere, too. Should they observe, ignore, or force Twitter? This paper examines for the first time (Germany) the Twitter-Communication after a national election (Bundestagswahl) and the process of building the new federal government (Bundesregierung).

Open Access (OA) as a new form of distributing scientific literature is broadly accepted by scholars, but in most disciplines the realization of the paradigm is progressing rather slowly. The reason for this lies, on the one hand, in a lack of incentives for individual authors. On the other hand, there are many different approaches to OA and their effects on market participants are complex. In this article we regard the implications of different OA models for scholars, publishers, libraries and funding organizations and try to explain the motivations behind the actions currently taking place on the scientific publishing market.

Far infrared reflectivity spectra of single crystal Pb0.85Sn0.15Te doped with Ni were measured in the temperature range between 10 K and 300 K. Analysis of the experimental spectra was made using a fitting procedure based on the modified model of plasmon-phonon interactions and the optical parameters were calculated. Two local modes were observed and their origin was discussed.

The article profiles the professional lives of saxophonist Pete King and Ronnie Scott.

The article discusses the Rainforest World Music Festival (RWMF) and the Borneo Jazz Festival that was held on two consecutive weekends on the island of Borneo, Indonesia, in July 2019.

The diffusion of e-commerce applications and solutions in many countries and industry sectors seems to have reached a level of maturity. This applies not only for large firms, but also for SMEs in three analysed industry sectors, i.e. manufacturing, retail/wholesale and banking/insurance, in Denmark, France, Germany, and the US. With the exception of France, a rather large number of SMEs in these countries responded that the implementation of e-commerce contributed substantially to improve existing operational processes and to expand markets. Although e-commerce technologies may be available hypothetically in all industries and firms, an efficient usage of e-commerce is closely related to a comprehensive implementation of more sophisticated solutions, e.g., online procurement or Internet-based supply chain management. Firms with an all-embracing approach utilizing many e-commerce applications are more often efficient than firms with a lower e-commerce diffusion rate in the sample analysed.

Abstract: How can academic library consortia provide access to literature despite increasing costs and decreasing budgets?In this paper, it is shown that making the fixed subscription rate variable by combining two relevant tariff models (flat-rate licence and pay-per-view) is an advantageous approach for consortia to react to the increasing (subscription) prices. A decision-making model is developed that considers the relevant parameters of pay-perview costs and user growth. The model is then applied to the Hessian library consortium (HeBIS). The empirical analysis shows that an optimal mix of rates for the publisher’s journals portfolio attains savings between 2% and 17% compared to a basic flat-rate licence.

ABSTRACTHelicobacter pyloriinduces motogenic and cytoskeletal responses in gastric epithelial cells. We demonstrate that these responses can be induced via independent signaling pathways that often occur in parallel. The cagpathogenicity island appears to be nonessential for induction of motility, whereas the elongation phenotype depends on translocation and phosphorylation of CagA.

The sensitivity of penetrant and magnetic particle testing (PT and MT) depends, among other things, on the quality and performance of the “detection media” (for PT designated as “product family”). The determination of the sensitivity is carried out on “reference pieces” with natural or artificial gap-like flaws by determining the visibility of the indications as a measure of the performance. European standardisation specifies the requirements of detection media, in accordance with prEN ISO 3452-2 for PT and EN ISO 9934-2 for MT for type and batch as well as for process control testing. This paper describes the evaluation and qualification of performance during the type testing procedure. The proposed methods are validated by experimental investigations using an image processing system for the determination of the visibility. The reliability of the proposed methods is discussed with reference to the qualification of the detection media.

Abstract: Standards provide for compatibility and can therefore constitute networks. A possible contribution of the discipline of IS is transcending traditional economic network analysis by incorporating an interdisciplinary view on networks with economic utility maximization and an agent-based computational economics (ACE) approach. In doing so, the complex dynamics in networks occasioned by the existence of network effects and socially situated agents with bounded rationality can be modelled using computational laboratories. This provides an important step towards evaluating and develop alternative socioeconomic structures with regard to their effects on individual behavior and social welfare.

Abstract: Inefficient trading processes (trade, clearing, settlement) and globally increasing transaction volumes and speed require a thorough integration and automation of cross-border trade processes. A variety of mostly XML-based initiatives struggle to become the industry wide communications standard. In this paper, the status quo of XML usage within and between globally operating banks and the role, recognition, and relevance of initiatives aimed at developing an industry wide standard to enable a Straight Through Processing are analysed. FpML, FIX, SWIFT and ISO 15022 are considered the most important standards. Many banks see XML document size (transformation performance and bandwidth) as an obstacle to using XML but nevertheless unanimously agree on its role as future lingua franca. Overall, due to functional as well as strategic reasons elaborated in the paper, ISO 15022 is expected to become the dominant standard.

Abstract: Networks utilizing modern communication technologies can offer competitive advantages to those using them wisely. But due to the existence of network effects, planning and operating cooperation networks is difficult. In this paper, the strategic situation of individual agents deciding on network participation is analysed. A systematic equilibrium analysis using computer-based simulations reveals principal solution scenarios for network agents and shows that network cooperation problems might frequently be not as difficult to resolve as often feared. In particular, strategic situations are identified showing that a majority of individuals might be better off getting the optimal solution from a central principal and that in many cases simple information intermediation can solve the start-up problem notorious in network economics.

Increased prevalence of small-sized low-density lipoprotein (LDL) subclass B (diameter < 25.5 nm) possibly is involved in the multifactorial process of cardiovascular disease in patients with end-stage renal disease. Given these epidemiological observations, mechanisms underlying the combined effect of a proinflammatory insult and LDL of different subclasses (subclass A, diameter 25.5 nm, and subclass B) in a cellular model were investigated. For this, human umbilical vein endothelial cells were preexposed to LDL, then stimulated with tumor necrosis factor-α (TNF-α). Modulatory effects of LDL phenotypes on the activation of adhesion molecules, monocyte adherence, and transcriptional activity of nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) were investigated. Our data show that subclass B LDLs were metabolized through nonspecific scavenger receptors and specific LDL-receptor pathways in endothelial cells. Furthermore, LDL subclass B in comparison to subclass A more effectively enhanced monocyte recruitment and adhesive properties of endothelial cells in response to TNF-α. These effects appeared not to be mediated by oxidative stress-responsive NF-κB because modulation of this transcription factor by LDL was moderate and similar for both LDL phenotypes. Conversely, effects of LDL subclass B were considered to be caused by augmented AP-1 binding activity. In conclusion, the present model provides new clues in atherogenic mechanisms of small-sized LDLs, which sensitize vascular cells to inflammatory signals more effectively than normal-sized LDLs. © 2002 by the National Kidney Foundation, Inc.

Various studies on mangroves and other tall trees rooting in high-salinity water have given compelling evidence that tension is not the only factor in water lifting as thought by plant physiologists. A characteristic feature of these trees is that the tissue cells, the apoplastic space and, in particular, the lumen and the inner walls of many xylem vessels of the roots, the trunk and the branches (up to the apex) contain mucilage. Data on single marine giant algal cells are presented that show that mucilage reduces the chemical activity of water. Longitudinal gradients in the chemical activity of water and interfacial forces are presumably the dominant forces for water lifting. In order to save water on its tortuous pathway to the uppermost foliage trees apparently use different strategies (as revealed by 1H-NMR imaging), e.g. reduction of the conducting xylem area in the branches at intermediate height by mucilage or interruption of the xylem water columns by gas-filled segments and water lifting through mucilage networks and surface films. Pressure bomb experiments over the entire height of the trees revealed clearly that balancing pressure values cannot be taken as a measure for xylem tension. Such values can be used generally for an estimation of the chemical potential of water in the xylem of leafy twigs under atmospheric pressure, µw,h=0, provided that a species-specific "threshold pressure" (depending on wood density, elastic forces of the tissue, hydraulic coupling between xylem and tissue cells, intercellular spaces, cellular osmotic pressure etc.) is subtracted from the balancing pressure values. Transpiration increases the "threshold pressure" considerably and in an unpredictable way. Thus, as shown here, predawn balancing pressure data taken at various heights can yield information about the height dependence of µw(measured at h=0) under field conditions, particularly when the water content of the xylem is simultaneously determined in a reliable manner (e.g. by the compression/decompression method in combination with centrifugation).

A polymer chain with attractive and repulsive forces between the building blocks is modeled by attaching a weight e−βfor every self-intersection and eγ/(2d)for every self-contact to the probability of an n-step simple random walk on ℤd, where β, γ>0 are parameters. It is known that for d=1 and γ>βthe chain collapses down to finitely many sites, while for d=1 and γ<βit spreads out ballistically. Here we study for d=1 the critical case γ=βcorresponding to the collapse transition and show that the end-to-end distance runs on the scale αn= $$\sqrt n$$ (log n)−1/4. We describe the asymptotic shape of the accordingly scaled local times in terms of an explicit variational formula and prove that the scaled polymer chain occupies a region of size αntimes a constant. Moreover, we derive the asymptotics of the partition function.

Morphine and the endogenous opioid peptide β-endorphin exert neuromodulatory as well as immunomodulatory effects, which are transduced by μ-opioid receptors. In this report we show that stimulation with interleukin-4 induces μ-opioid receptor transcripts in human primary blood cells (T cells and polymorphonuclear leukocytes), immune cell lines (Raji, U-937, and HMEC-1), and dendritic cells. In nonstimulated immune cells this gene is silent. In addition, μ receptor transcription is up-regulated by interleukin-4 in cultures of primary rat neurons. Transient transfection experiments in Raji and SH SY5Y neuronal cells with human and rat reporter gene constructs linked the interleukin-4 effect directly to cis-active μ receptor promoter elements located at nucleotide −997 on the human gene and nucleotide −727 on the rat gene. The interleukin-4 response elements function orientation independently. They bind STAT6 transcription factors as shown by electrophoretic mobility shift assays. In the human gene, a single nucleotide polymorphism within the interleukin-4 response element reduces the trans-activating potential of this element by 50%, which may affect the phenotype of persons carrying this variation. These findings provide a molecular basis for understanding bidirectional interactions between the opioid system and the immune system.

In the last decade there has been an enormous progress in the mathematical understanding of one-dimensional polymer measures, which are path measures that suppress self-intersections. We are currently in the situation that many interesting questions have either been answered, or that essential new ideas are needed. In this survey paper, we discuss the most relevant results, open questions, and heuristics.

We consider the large-time behavior of the solution $$ u:[0,\infty ) \times \mathbb{Z} \to [0,\infty ) $$ to the parabolic Anderson problem ∂tu=κΔu+ξu with initial data u(0, ·)=1 and non-positive finite i.i.d. potentials $$ (\xi (z))_{z \in \mathbb{Z}} $$ . Unlike in dimensions d≥2, the almost-sure decay rate of u(t, 0) as t→∞ is not determined solely by the upper tails of ξ(0); too heavy lower tails of ξ(0) accelerate the decay. The interpretation is that sites x with large negative ξ(x) hamper the mass flow and hence screen off the influence of more favorable regions of the potential. The phenomenon is unique to d=1. The result answers an open question from our previous study [BK00] of this model in general dimension.

□ Pathogenese der HCV-Infektion und virale Charakteristika: Das Hepatitis-C-Virus (HCV) gilt weltweit als häufigster Verursacher der chronischen Non-A-non-B-Hepatitis, die schleichend in eine Leberzirrhose übergehen kann und mit einem erhöhten Risiko zum primären Leberzellkarzinom assoziiert ist. Der hohe Anteil chronifizierender Verläufe nach HCV-Infektion läßt sich durch die ausgeprägte Variabilität antigener Virusepitope erklären, die nur eine unzureichende Immunantwort induzieren und so das konsekutive Persistieren des Virus im Wirtsorganismus ermöglichen. Die Heterogenität von HCV innerhalb einer Viruspopulation bzw. zwischen verschiedenen HCV-Isolaten läßt sich auf genomischer Ebene charakterisieren: man differenziert HCV-Varianten innerhalb einer Viruspopulation mit Sequenzunterschieden von weniger als 5% (sogenannte HCV-Quasispezies) von HCV-Isolaten mit Sequenzdivergenzen zwischen 10 und 20% (HCV-Genotypen bzw._-Subtypen). Insbesondere zwischen HCV-Genotypen zeigen sich Unterschiede sowohl in Antigenität und therapeutischer Empfindlichekeit als auch in ihrer geographischen Verteilung. □ Virale Prädiktoren der HCV-Therapie: In einer Metaanalyse von 18 Therapiestudien zeigt sich, daß der Erfolg der Interferontherapie von HCV-Infektionen wesentlich determiniert wird durch HCV-Genotyp 1 und hohe HCV-RNA-Titer (>106Genomäquivalente/ml). Einen wesentlichen Fortschritt in der Therapie von Patienten mit chronischer HCV-Infektion scheint die Kombinationstherapie aus Interferon und Ribavirin zu bringen. In den beiden bislang publizierten multizentrischen Studien profitierten insbesondere Patienten mit ungünstigen viralen Prädiktoren — HCV-Genotyp 1 oder hohe HCV-RNA-Titer — dauerhaft von einer Kombinationstherapie. □ Schlußfolgerung und Ausblick: Sowohl aus virologischer als auch aus klinischer Sicht stellt die HCV-Infektion eine Herausforderung dar. Die Kombinationstherapie aus Interferon und Ribavirin stellt einen entscheidenden Fortschritt sowohl in der Retherapie als auch in der Primärtherapie der Hepatitis C dar. Trotz dieses neuen Therapiekonzepts müssen weitere Strategien zur Verbesserung der therapeutischen Ergebnisse entwickelt werden. Hierzu zählen Therapien mit Modifikationen der Interferongaben (höhere und tägliche Dosierungen, längere Therapiedauer, Verwendung von pegylierten Interferonen mit verzögerter Freisetzung), Kombinationstherapien von Interferon mit anderen bekannten antiviralen Substanzen (Amantadin), mit Immunodulatoren (GM-CSF, Thymosin α1), die Entwicklung von neuartigen antiviralen Hemmstoffen (Hemmung der viralen Protease, Helikase oder Polymerase) sowie die Exploration antiviraler molekularer Strategien, wie die Gabe von spezifischen Ribozymen, Antisenseoligonukleotiden oder der DNA-Vakzinierung. Endgültiges Ziel ist und bleibt allerdings die Entwicklung einer wirksamen Impfprophylaxe.

In diesem Beitrag wird am Beispiel der Produktion von Radiator-Heizungskörpern die Lösung des Zuschnittproblems der Vor- und Rücklaufrohre mit einem heuristisch-optimierenden Verfahren dargestellt. Die heuristische Vorschaltphase des Verfahrens ermöglicht bei geschickter Wahl der Kriterien eine Reduktion der Dimension des Verschnittproblems, ohne die Lösungsgüte unzulässig einzuschränken. Im Rahmen der reduzierten Problembeschreibung folgt anschließend die Optimierungsphase durch Anwendung der Linearen Programmierung. Es werden Testergebnisse im praktischen Einsatz des Verfahrens beschrieben. Weiterhin wird die Betrachtung der Integration des Verfahrens in ein globales EDV-gestütztes Produktionsplanungs- und -steuerungssystem behandelt, indem die Schnittstellen in der Material- und Terminbewirtschaftung zwischen dem stapelorientierten Planungskonzept und der Prozeßkontrolle einer NC-Sägeanlage definiert werden. This contribution describes the solution of an one-dimensional cutting problem in the context of a production control system. The solution of the cutting problem is demonstrated at the example of the production of central heating radiator units. The procedure is subdivided in an initial heuristic phase in order to concentrate the problem description. Afterwards an optimization phase is added to find the best solution of the reduced problem by using Linear Programming. Test results of field experiences are given. The last part of the contribution shows the integration of this solution in the global material and machine planning and control moduls. This is done by the determination of the interfaces of the batch oriented production control system and the process control of an NC saw machine.

Membrane adenylate cyclase from rat heart was activated by the two gut peptides secretin and vasoactive intestinal peptide (VIP), glucagon, and the ß-adrenergic drug isoproterenol, in the presence of guanosine 5'-triphosphate (GTP). With all the stimuli tested, the optimal magnesium concentration was 5 mM, i.e. in excess over the 0.5 mM ATP substrate concentration and 0.01 mM GTP used as cofactor. Under these conditions, half-maximal adenylate cyclase activation with glucagon, secretin, and VIP was achieved at concentrations of 0.5, 0.5 and 1.0 µM, respectively. Data obtained with the secretin (7–27) fragment, a secretin antagonist, indicate that secretin and VIP acted on the same binding sites, which differed from glucagon binding sites. Structural requirements for secretin activation of cardiac adenylate cyclase were evaluated by comparing the potency and efficacy of parent peptides and synthetic analogs. The gastric inhibitory peptide GIP was inactive. When using 13 mono-or bi-substituted analogs, it appeared that amino acids in positions 1, 2, 3, 4 and 6 were of major importance while those in position 5 and 11 played a relatively minor role.

In Germany, numerous technical schools were established between 1821 and 1836. The main purpose of these schools was to supply public service and industry with technical personnel. Indeed, a great number among the graduates entered positions in mining, military, and public building. The public service's demands influenced the schools' organization and curricula. On the contrary, in the time period before 1870, only few graduates obtained positions in industry. The author's conclusion is, that the technical schools contributed little to the early industrialization in Germany.

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We analyzed the effect of the PAF receptor antagonist (+)-cis-3,5-dimethyl-2-(3-pyridyl) thiazolidin-4-one hydrochloride (SM-12502) on the release of leukotriene B4 and IL-8 from human leukocytes. Peripheral blood from healthy donors was separated in two different fractions: polymorphonuclear leukocytes (PMN) and a lymphocyte, monocyte and basophil granulocyte cell fraction (LMB). After incubation of the cell population with different concentrations of SM-12502 the cells were subsequently stimulated with either the Ca ionophore A23187, the bacterial derived peptide fMLP, or with an activator of heterotrimetric G-proteins, the sodium fluoride (NaF, in the presence of Al3+). The PAF receptor antagonist led to a concentration and time dependent inhibition of LTB4 formation and IL-8 release from PMN and LMB. Our data clearly indicate an inhibitory effect of the PAF receptor antagonist SM-12502 on the formation of mediators of the lipoxygenase pathway and on the release of IL-8.

The metabolism of leukotriene D4to leukotriene E4by a dipeptidase of kidney tissue is strongly inhibited by cilastatin (MK 0791) a known renal dehydropeptidase-I inhibitor. The comparison with similar enzyme activities from other tissues (liver, lung, serum, polymorphonuclear granulocytes) revealed a high specifity of cilastatin for the kidney enzyme which was found to be associated with the microsomal fraction. The lowest detectable inhibitory concentration of cilastatin within renal tissue was 8 × 10−8M.

We prove that a self-avoiding random walk on the integers with bounded increments grows linearly. We characterize its drift in terms of the Frobenius eigenvalue of a certain one parameter family of primitive matrices. As an important tool, we express the local times as a two-block functional of a certain Markov chain, which is of independent interest.

To elucidate the role of bradykinin in the cardiac actions of angiotensin converting enzyme (ACE) inhibitors, experiments were performed in isolated ischaemic hearts from guinea pigs and rats treated with the ACE inhibitor ramipril and the bradykinin-antagonist D-Arg[Hyp2, Thi5,8,D-Phe7]BK.

Consider a one-dimensional walk (Sk)khaving steps of bounded size, and weight the probability of the path with some factor 1−α∈(0,1) for every single self-intersection up to timen. We prove thatSn/SSconverges towards some deterministic number called the effective drift of the self-repellent walk. Furthermore, this drift is shown to tend to the basic drift as α tends to 0 and, as α tends to 1, to the self-avoiding walk's drift which is introduced in [10]. The main tool of the present paper is a representation of the sequence of the local times as a functional of a certain Markov process.

Antagonists of the platelet fibrinogen receptor (GP IIb/IIIa receptor) are expected to be a new promising class of antithrombotic agents. The binding of fibrinogen to the fibrinogen receptor depends on an Arg-Gly-Asp-Ser (RGDS) tetrapeptide recognition motif. Structural modifications of the RGDS lead have led to the discovery of a non-peptide RGD mimetic GP IIb/IIIa antagonist20(S 1197). Compound20inhibits dose-dependently and reversibly human platelet aggregation. Modeling studies based on structure-activity data revealed the following structural features of the drug as important for receptor binding: the amidino group, the carboxylate group, hydrophobic substitutions at the carboxyl-terminus and at the side chain carrying the positive charge, the carboxyl-terminal NH group of the β-amino acid as a hydrogen bond donor and one oxygen atom of the hydantoin as a hydrogen bond acceptor. The ethyl ester prodrug of20(S 5740) is an orally active antithrombotic agent which has the potential to be used to treat and prevent thrombotic diseases in humans.

Summary: Antagonists of the platelet fibrinogen receptor (GP IIb/IIIa receptor) are expected to be a new promising class of antithrombotic agents. The binding of fibrinogen to the fibrinogen receptor depends on an Arg-Gly-Asp-Ser (RGDS) tetrapeptide recognition motif. Structural modifications of the RGDS lead have led to the discovery of a non-peptide RGD mimetic GP IIb/IIIa antagonist20 (S 1197). Compound20 inhibits dose-dependently and reversibly human platelet aggregation. Modeling studies based on structure-activity data revealed the following structural features of the drug as important for receptor binding: the amidino group, the carboxylate group, hydrophobic substitutions at the carboxyl-terminus and at the side chain carrying the positive charge, the carboxyl-terminal NH group of the β-amino acid as a hydrogen bond donor and one oxygen atom of the hydantoin as a hydrogen bond acceptor. The ethyl ester prodrug of20 (S 5740) is an orally active antithrombotic agent which has the potential to be used to treat and prevent thrombotic diseases in humans.

It has been proposed that two distinct signals are required for the triggering of the precursors of antibody-forming bone marrow-derived cells (B cells): (a) the binding of antigen or of a mitogen to the corresponding receptor sites on B-cell membranes and (b) the interaction of activated C3 with the C3 receptor of B lymphocytes. There is growing evidence that B-cell mitogens and T (thymus-derived cell)-independent antigens are capable of activating the alternate pathway of the complement system (bypass). Therefore, the effect of another potent bypass inducer was investigated with regard to B-cell activation and the role of C3. Purified, pyrogen-free cobra venom factor was mitogenic for both T and B lymphocytes (cortisone-resistant mouse thymus cells and lymph node lymphocytes from congenitally athymic mice). Venom factor could substitute for T cells by restoring the potential of antibody formation to sheep red blood cells in mouse B-cell cultures supplemented with macrophages or 2-mercaptoethanol. Venom factor may be capable of conferring activated C3 to the C3 receptor of B lymphocytes: preincubation of lymphoid cells with homologous serum or plasma, 10 mM EDTA, and sepharose-coupled venom factor converted with serum to an enzyme active against C3, inhibited their capacity to subsequently form rosettes with sheep erythrocytes sensitized with amboceptor and C5-deficient mouse complement. In the absence of EDTA, preincubation of freshly prepared B-cell suspensions with C3-sufficient homologous serum also blocked their subsequent interaction with complement-sensitized erythrocytes and at the same time rendered them reactive to an otherwise T-cell-specific mitogen. Moreover, mitogen induced B-cell proliferation in lymph node (but not in spleen) cell cultures, appeared to depend on the availability of exogenous C3: zymosan-absorbed fetal bovine serum (only 8.3% site-forming units remaining) supported T-cell activation by phytohemagglutinin, concanavalin A, and venom factor, but failed to sustain B-cell stimulation by pokeweed mitogen, lipopolysaccharide, and venom factor. T-cell-dependent antibody formation in composite cultures containing T cells or T-cell-substituting B-cell mitogens, B cells, and macrophages, always required the presence of C3-sufficient serum.

Recently, we described the presence of a blocking factor (BF) in rat serum, which inhibited the histamine release from rat mast cells in vivo and in vitro. The blocking activity was demonstrated in human serum as well. Qualitative analysis of the purified preparation demonstrated a major component with an apparent molecular weight of 70,000 daltons. In human serum the blocking factor was identified as transferrin (TF)_by serological and biochemical methods. BF (DEAE-peak 1) and the iron binding proteins transferrin and lactoferrin (LF) are shown to inhibit the histamine release in vitro. The dose response curves reveal that inhibition by these proteins is dependent on their degree of iron saturation. Furthermore, unlike lactoferrin, the effects of transferrin and BF (DEAE-peak 1) follow the same pattern. Their mechanism of action remains to be elucidated.

A complement-independent eosinophil chemotactic factor (ECF) is described which is released from peripheral leukocytes of allergic and normal human volunteers after antigen stimulation and after exposure to anti-IgE. Dose response and time-release curves for ECF and histamine run closely parallel in this system. Histamine by itself is shown to have no effect on chemotaxis at the concentrations present in antigen-induced release, but is inhibitory at very high concentrations. Evidence suggests that the ECF released from human leukocytes is derived from basophils and is similar, or identical, to the ECF released from mast cells.

Aus Leuchssehen Anhydriden und 1-Hydroxypiperidin-hydrochlorid wurden Aminosäure-1-hydroxypiperidinester-hydrochloride dargestellt, die am besten mit Woodwards Reagens K oder mit Methyl-äthinyl-diäthylamin in N-Acyl-dipeptid-1-hydroxypiperidinester überführbar sind. Bei der anschließenden Umsetzung mit Aminosäure-methylester-hydrochloriden unter Zusatz von Natriumacetat (Peptidsynthese nach G. T. Young) erhielt man in z. T. sehr guten Ausbeuten N-Acyl-tripeptid-methylester. Der Vorteil dieser Methode besteht in der Vermeidung von freien Dipeptidestern und in der Racemisierungs-freien Synthese der Tripeptid-Derivate.