A role for the src family kinase Fyn in NK cell activation and the formation of the repertoire of Ly49 receptors.

NK cell function is regulated by a dual receptor system, which integrates signals from triggering receptors and MHC class I-specific inhibitory receptors. We show here that the src family kinase Fyn is required for efficient, NK cell-mediated lysis of target cells, which lack both self-MHC class I molecules and ligands for NKG2D, an activating NK cell receptor. In contrast, NK cell inhibition by the MHC class I-specific receptor Ly49A was independent of Fyn, suggesting that Fyn is specifically required for NK cell activation via non-MHC receptor(s). Compared to wild type, significantly fewer Fyn-deficient NK cells expressed the inhibitory Ly49A receptor. The presence of a transgenic Ly49A receptor together with its H-2(d) ligand strongly reduced the usage of endogenous Ly49 receptors in Fyn-deficient mice. These data suggest a model in which the repertoire of inhibitory Ly49 receptors is formed under the influenced of Fyn-dependent NK cell activation as well as the respective MHC class I environment. NK cells may acquire Ly49 receptors until they generate sufficient inhibitory signals to balance their activation levels. Such a process would ensure the induction of NK cell self-tolerance.

Positive Torsional Strain Causes the Formation of a Four-Way Junction at Replication Forks.

Research by L. Postow, C. Ullsperger, R.W. Keller, C. Bustamante, A.V. Vologodskii, and N.R. Cozzarelli, J. Biol. Chem. 2001, 276, 2790 Condensation and commentary by Alexander Bucka and Andrzej Stasiak, Universite ´ de Lausanne, Switzerland Purpose of the Study To demonstrate that positive torsional strain generated during DNA replication can lead to reversals of replication forks and, consequently can result in the formation of four-way DNA junctions

Visualization of recombination intermediates produced by RAD52-mediated single-strand annealing.

Double-strand breaks (DSBs) occur frequently during DNA replication. They are also caused by ionizing radiation, chemical damage or as part of the series of programmed events that occur during meiosis. In yeast, DSB repair requires RAD52, a protein that plays a critical role in homologous recombination. Here we describe the actions of human RAD52 protein in a model system for single-strand annealing (SSA) using tailed (i.e. exonuclease resected) duplex DNA molecules. Purified human RAD52 protein binds resected DSBs and promotes associations between complementary DNA termini. Heteroduplex intermediates of these recombination reactions have been visualized by electron microscopy, revealing the specific binding of multiple rings of RAD52 to the resected termini and the formation of large protein complexes at heteroduplex joints formed by RAD52-mediated annealing.

Paclitaxel-eluting biodegradable synthetic vascular prostheses: a step towards reduction of neointima formation?

BACKGROUND: Clinical small-caliber vascular prostheses are unsatisfactory. Reasons for failure are early thrombosis and late intimal hyperplasia. We thus prepared biodegradable small-caliber vascular prostheses using electrospun polycaprolactone (PCL) with slow-releasing paclitaxel (PTX), an antiproliferative drug. METHODS AND RESULTS: PCL solutions containing PTX were used to prepare nonwoven nanofibre-based 2-mm ID prostheses. Mechanical morphological properties and drug loading, distribution, and release were studied in vitro. Infrarenal abdominal aortic replacement was carried out with nondrug-loaded and drug-loaded prostheses in 18 rats and followed for 6 months. Patency, stenosis, tissue reaction, and drug effect on endothelialization, vascular remodeling, and neointima formation were studied in vivo. In vitro prostheses showed controlled morphology mimicking extracellular matrix with mechanical properties similar to those of native vessels. PTX-loaded grafts with suitable mechanical properties and controlled drug-release were obtained by factorial design. In vivo, both groups showed 100% patency, no stenosis, and no aneurysmal dilatation. Endothelial coverage and cell ingrowth were significantly reduced at 3 weeks and delayed at 12 and 24 weeks in PTX grafts, but as envisioned, neointima formation was significantly reduced in these grafts at 12 weeks and delayed at 6 months. CONCLUSIONS: Biodegradable, electrospun, nanofibre, polycaprolactone prostheses are promising because in vitro they maintain their mechanical properties (regardless of PTX loading), and in vivo show good patency, reendothelialize, and remodel with autologous cells. PTX loading delays endothelialization and cellular ingrowth. Conversely, it reduces neointima formation until the end point of our study and thus may be an interesting option for small caliber vascular grafts.

Statmedia 3 : activitats on-line individualitzades d'estadística i matemàtiques als ensenyaments de Ciències Experimentals i Socials

El projecte Statmedia 3 ha consolidat definitivament la proposta de les assignatures Bioestadística de Biologia, Anàlisi de dades de Ciències Ambientals i d’Estadística Matemàtica de la Diplomatura renovant una part del material creat amb Statmedia 2. S’han inclòs a més Matemàtiques d’Ambientals i Introducció a la Probabilitat del Grau d’Estadística. L’anterior MQD abastava només pràctiques mentre que aquest projecte permet una oferta diversa d’activitats individualitzades. La individualització consisteix en que cada estudiant rep una proposta de cas personalitzada amb dades diferents. Les activitats poden ser programades presencialment o no, però la clau de l’èxit de l’activitat és que l’alumne obtingui reconeixement del seu treball en l’avaluació continuada. La valoració que fan als alumnes de Statmedia és molt bo, i observem que es produeix una millora en els resultats acadèmics. Statmedia 3 ha implicat un important esforç en la vessant informàtica del projecte, la barreja de tecnologies que utilitzem son punteres: Ajax, servlets i applets Java... Hem posat a punt un assistent on-line per dissenyar documents i planificar activitats que facilita la tasca dels professors. La nostre participació en primera línea del procés de convergència a l’EEES ens ha permès anticipar alguns canvis, i s’ha traduït en que el claustre del Departament d’Estadística assumís que Statmedia és una metodologia essencial dels seus plans docents. El projecte continua en un quart projecte MQD consecutiu, on desplegarem la nova tecnologia implementada. L’objectiu principal serà dotar a les assignatures dels 7 graus on participa el departament d’activitats individualitzades en forma de casos pràctics, problemes i proves diverses. La col·lecció de material emmagatzemada en la nostra biblioteca, forjada després de quasi deu anys de treball continuat, juntament amb l’experiència acumulada de com utilitzar Statmedia de la forma més eficient han començat a ser explotades en els nous graus aquest mateix curs 2009-2010.

Establishment and Characterization of a Cell Line from the Mosquito Anopheles albimanus (Diptera: Culicidae)

A new cell line designated LSB-AA695BB, was established from embryos of the mosquito Anopheles albimanus. The primary culture was initiated in April, 1995, and the first passage was made 48 days later. Serial subcultures of the cells have been carried through 90 passages from Abril 1995 to February 1996. The cells were grown at 28°C in MK/VP12 medium, supplemented with 20% fetal bovine serum; the pH tolerance ranged between 6.8 to 7.0. The cells have also been adapted to MM/VP12 medium under the same pH, temperature and serum concentration. The majority of the cells were a fibroblast-type. Isozyme characterization showed a pattern similar to that of An. albimanus pupae and adults but distinct from Ae. taeniorhynchus and Ae. albopictus (C6/36) mosquito cell lines. The culture was shown to be free of mycoplasma, bacteria and fungi. Microsporidia contamination of transovarial transmission was controlled with 6.0 mg/ml of albendazole

Sincere Lobby Formation

This paper analyzes endogenous lobbying over a unidimensional policy issue. Individuals differ in policy preferences and decide either to join one of two opposite interest lobbies or not to take part in lobbying activities. Once formed, lobbies make contributions to the incumbent government in exchange for a policy favor as in a common-agency model. A "sincere-lobby-formation" condition for equilibrium is introduced: an individual joins a lobby if their gain from the policy change that this lobby might achieve exceeds a contribution fee. Thus, an equilibrium occurs only if no lobby member would prefer their lobby to cease to exist. I show the existence of an equilibrium with two organized lobbies. Individuals with more extreme preferences are more likely to join lobbying activities. I fi…nd that lobbying somewhat moderates the government's preferences, i.e., it shifts the …final policy in favor of individuals who are initially disadvantaged by the government's pro- or anti-policy preferred position. Under a utilitarian government, however, lobbying does not affect the fi…nal policy, and political competition results in a socially optimal outcome. JEL classi…cation: D72. Keywords: Sincere lobby formation; common agency; endogenous lobbying.

Phase II study of weekly plitidepsin as second-line therapy for small cell lung cancer.

OBJECTIVE: To evaluate the antitumor activity and safety profile of plitidepsin administered as a 1h weekly intravenous (i.v.) infusion of 3.2mg/m(2) to patients with small cell lung cancer (SCLC) who relapsed or progressed after one line of chemotherapy. PATIENTS AND METHODS: This was a multicenter, open-label, single-arm, exploratory, phase II clinical trial. Treatment lasted until disease progression, unacceptable toxicity, patient refusal or treatment delay for >2 weeks. Objective response rate (primary efficacy endpoint) was evaluated according to response evaluation criteria in solid tumors (RECIST). The rate of stable disease (SD) lasting for at least 6 months and time-to-event variables were secondary endpoints of efficacy. Toxicity was assessed using National Cancer Institute Common Toxicity Criteria (NCI-CTC) version 2.0. RESULTS: Twenty pretreated SCLC patients (median age, 60 years) with extensive (n=13) or limited-stage disease (n=7) received a total of 24 treatment cycles (median, one cycle per patient; range, 1-2). Objective tumor responses were not observed and only one of the 17 evaluable patients had SD. With a median follow-up of 11.8 months, the progression-free survival and the median overall survival were 1.3 months and 4.8 months, respectively. The most troubling or common toxicities were fatigue, muscle weakness, lymphopenia, anemia (no patients showed neutropenia), and asymptomatic, non-cumulative increase of transaminases levels and alkaline phosphatase. CONCLUSION: This clinical trial shows that a cycle of 1h weekly i.v. infusion of plitidepsin (3.2mg/m(2)) was generally well tolerated other than fatigue and muscle weakness in patients with pretreated SCLC. One patient died due to multi-organ failure. The absence of antitumor activity found here precludes further studies of this plitidepsin schedule as second-line single-agent treatment of SCLC.

Producing on-line ultrapure dialysis fluid.

The process of on-line generation of ultrapure dialysis fluid is a core prerequisite for the safe execution of modern renal replacement therapies such as on-line hemodiafiltration and high-flux hemodialysis. In these extracorporeal treatments with variable degrees of convection, significant volumes of plasma water are removed and replaced with dialysis fluid, which must occur without causing harm to the patient. Historically, on-line generation of sterile and pyrogen-free physiological substitution fluid by the process of membrane ultrafiltration of fresh dialysis fluid has its origin in hemofiltration, a purely convective therapy. Development of this and later therapies is described in the historical context of a successful effort over decades to overcome the above formidable challenge, which was provided jointly by pioneering clinical investigators and a resourceful dialysis industry.

Mechanisms of formation and function of eosinophil lipid bodies: inducible intracellular sites involved in arachidonic acid metabolism

Lipid bodies, inducible lipid-rich cytoplasmic inclusions, are characteristically abundant in cells associated with inflammation, including eosinophils. Here we reviewed the formation and function of lipid bodies in human eosinophils. We now have evidence that the formation of lipid bodies is not attributable to adverse mechanisms, but is centrally mediated by specific signal transduction pathways. Arachidonic acid and other cis fatty acids by an NSAID-inhibitable process, diglycerides, and PAF by a 5-lipoxygenase dependent pathway are potent stimulators of lipid body induction. Lipid body formation develops rapidly by processes that involve PKC, PLC, and de novo mRNA and protein synthesis. These structures clearly serve as repositoires of arachidonyl-phospholipids and are more than inert depots. Specific enzymes, including cytosolic phospholipase A2, MAP kinases, lipoxygenases and cyclooxygenases, associate with lipid bodies. Lipid bodies appear to be dynamic, organelle-like structures involved in intracellular pathways of lipid mobilization and metabolism. Indeed, increases in lipid body numbers correlated with enhanced production of both lipoxygenase- and cyclooxygenase-derived eicosanoids. We hypothesize that lipid bodies are distinct inducible sites for generating eicosanoids as paracrine mediators with varied activities in inflammation. The capacity of lipid body formation to be specifically and rapidly induced in leukocytes enhances eicosanoid mediator formation, and conversely pharmacologic inhibition of lipid body induction represents a potential novel and specific target for anti-inflammatory therapy.

Wnt secretion and gradient formation.

Concentration gradients formed by the lipid-modified morphogens of the Wnt family are known for their pivotal roles during embryogenesis and adult tissue homeostasis. Wnt morphogens are also implicated in a variety of human diseases, especially cancer. Therefore, the signaling cascades triggered by Wnts have received considerable attention during recent decades. However, how Wnts are secreted and how concentration gradients are formed remains poorly understood. The use of model organisms such as Drosophila melanogaster has provided important advances in this area. For instance, we have previously shown that the lipid raft-associated reggie/flotillin proteins influence Wnt secretion and spreading in Drosophila. Our work supports the notion that producing cells secrete Wnt molecules in at least two pools: a poorly diffusible one and a reggie/flotillin-dependent highly diffusible pool which allows morphogen spreading over long distances away from its source of production. Here we revise the current views of Wnt secretion and spreading, and propose two models for the role of the reggie/flotillin proteins in these processes: (i) reggies/flotillins regulate the basolateral endocytosis of the poorly diffusible, membrane-bound Wnt pool, which is then sorted and secreted to apical compartments for long-range diffusion, and (ii) lipid rafts organized by reggies/flotillins serve as "dating points" where extracellular Wnt transiently interacts with lipoprotein receptors to allow its capture and further spreading via lipoprotein particles. We further discuss these processes in the context of human breast cancer. A better understanding of these phenomena may be relevant for identification of novel drug targets and therapeutic strategies.

VeriStrat(®) has a prognostic value for patients with advanced non-small cell lung cancer treated with erlotinib and bevacizumab in the first line: Pooled analysis of SAKK19/05 and NTR528.

BACKGROUND: VeriStrat(®) is a serum proteomic test used to determine whether patients with advanced non-small cell lung cancer (NSCLC) who have already received chemotherapy are likely to have good or poor outcomes from treatment with gefitinib or erlotinib. The main objective of our retrospective study was to evaluate the role of VS as a marker of overall survival (OS) in patients treated with erlotinib and bevacizumab in the first line. PATIENTS AND METHODS: Patients were pooled from two phase II trials (SAKK19/05 and NTR528). For survival analyses, a log-rank test was used to determine if there was a statistically significant difference between groups. The hazard ratio (HR) of any separation was assessed using Cox proportional hazards models. RESULTS: 117 patients were analyzed. VeriStrat classified patients into two groups which had a statistically significant difference in duration of OS (p=0.0027, HR=0.480, 95% confidence interval: 0.294-0.784). CONCLUSION: VeriStrat has a prognostic role in patients with advanced, nonsquamous NSCLC treated with erlotinib and bevacizumab in the first line. Further work is needed to study the predictive role of VeriStrat for erlotinib and bevacizumab in chemotherapy-untreated patients.