Emergence and fate of stem cell-like Tcf7⁺ CD8⁺ T cells during a primary immune response to viral infection.

In response to infection, naïve CD8 <sup>+</sup> T (T <sub>N</sub> ) cells yield a large pool of short-lived terminal effector (T <sub>TE</sub> ) cells that eliminate infected host cells. In parallel, a minor population of stem cell-like central memory (T <sub>CM</sub> ) cells forms, which has the capacity to maintain immunity after pathogen clearance. It has remained uncertain whether stem-like T <sub>CM</sub> cells arise by dedifferentiation from a subset of cytolytic T <sub>TE</sub> cells or whether priming generates stem-like cells capable of seeding the T <sub>CM</sub> compartment and, if so, when cytolytic T <sub>TE</sub> cells branch off. Here, we show that CD8 <sup>+</sup> T cells with stem-like properties, which are identified by the expression of TCF1 (encoded by Tcf7), are present across the primary response to infection. Priming programs T <sub>N</sub> cells to undergo multiple cell divisions, over the course of which TCF1 expression is maintained. These TCF1 <sup>+</sup> cells further expand relatively independently of systemic inflammation, antigen dose, or affinity, and they quantitatively yield TCF1 <sup>+</sup> T <sub>CM</sub> cells after pathogen clearance. Inflammatory signals suppress TCF1 expression in early divided TCF1 <sup>+</sup> cells. TCF1 down-regulation is associated with the irreversible loss of self-renewal capacity and the silencing of stem/memory genes, which precedes the stable acquisition of a T <sub>TE</sub> state. TCF1 expression restrains cell cycling, explaining in part the limited expansion of TCF1 <sup>+</sup> relative to TCF1 <sup>-</sup> cells during the primary response. Thus, our data are consistent with terminal differentiation of effector cells being a step-wise process that is initiated by inflammation in primed stem-like cells, which would otherwise become central memory cells by default

Radio emission of extensive air shower at CODALEMA: Polarization of the radio emission along the v*B vector

Cosmic rays extensive air showers (EAS) are associated with transient radio emission, which could provide an efficient new detection method of high energy cosmic rays, combining a calorimetric measurement with a high duty cycle. The CODALEMA experiment, installed at the Radio Observatory in Nancay, France, is investigating this phenomenon in the 10^17 eV region. One challenging point is the understanding of the radio emission mechanism. A first observation indicating a linear relation between the electric field produced and the cross product of the shower axis with the geomagnetic field direction has been presented (B. Revenu, this conference). We will present here other strong evidences for this linear relationship, and some hints on its physical origin.Comment: Contribution to the 31st International Cosmic Ray Conference, Lodz, Poland, July 2009. 4 pages, 8 figures. v2: Typo fixed, arxiv references adde

A phase I study of a new polyamine biosynthesis inhibitor, SAM486A, in cancer patients with solid tumours

Because tumour cell proliferation is highly dependent upon up-regulation of de-novo polyamine synthesis, inhibition of the polyamine synthesis pathway represents a potential target for anticancer therapy. SAM486A (CGP 48664) is a new inhibitor of the polyamine biosynthetic enzyme S-adenosylmethionine decarboxylase (SAMDC), more potent and specific than the first-generation SAMDC inhibitor methylglyoxal (bis) guanylhydrazone (MGBG). Preclinical testing confirmed promising antiproliferative activity. In this phase I study, SAM486A was given 4-weekly as a 120 h infusion. 39 adult cancer patients were enrolled with advanced/refractory disease not amenable to established treatments, PS ≤ 2, adequate marrow, liver, renal and cardiac function. Doses were escalated in 100% increments without toxicity in 24 pts from 3 mg m–2cycle–1up to 400 mg m–2cycle–1. At 550 and 700 mg m–2cycle–1reversible dose-limiting neutropenia occurred. Other toxicities included mild fatigue, nausea and vomiting. No objective remission was seen. Pharmakokinetic analysis showed a terminal half-life of approximately 2 days. AUC and Cmax were related to dose; neutropenia correlated with AUC. The recommended dose for further phase II studies on this schedule is 400 mg m–2cycle–1. © 2000 Cancer Research Campaig

Geomagnetic origin of the radio emission from cosmic ray induced air showers observed by CODALEMA

The new setup of the CODALEMA experiment installed at the Radio Observatory in Nancay, France, is described. It includes broadband active dipole antennas and an extended and upgraded particle detector array. The latter gives access to the air shower energy, allowing us to compute the efficiency of the radio array as a function of energy. We also observe a large asymmetry in counting rates between showers coming from the North and the South in spite of the symmetry of the detector. The observed asymmetry can be interpreted as a signature of the geomagnetic origin of the air shower radio emission. A simple linear dependence of the electric field with respect to vxB is used which reproduces the angular dependencies of the number of radio events and their electric polarity.Comment: 9 pages, 15 figures, 1 tabl

A phase I study with MAG-camptothecin intravenously administered weekly for 3 weeks in a 4-week cycle in adult patients with solid tumours

In MAG-camptothecin (MAG-CPT), the topoisomerase inhibitor camptothecin is linked to a water-soluble polymer. Preclinical experiments showed enhanced antitumour efficacy and limited toxicity compared to camptothecin alone. Prior phase I trials guided the regimen used in this study. The objectives were to determine the maximum tolerated dose, dose-limiting toxicities, safety profile, and pharmacokinetics of weekly MAG-CPT. Patients with solid tumours received MAG-CPT intravenously administered weekly for 3 weeks in 4-week cycles. At the starting dose level ( 80 mg m(-2) week(-1)), no dose-limiting toxicities occurred during the first cycle (n = 3). Subsequently, three patients were enrolled at the second dose level ( 120 mg m(-2) week(-1)). Two of three patients at the 80 mg m(-2) week(-1) cohort developed haemorrhagic cystitis ( grade 1/3 dysuria and grade 2/3 haematuria) during the second and third cycles. Next, the 80 mg m(-2) week(-1) cohort was enlarged to a total of six patients. One other patient at this dose level experienced grade 1 haematuria. At 120 mg m(-2) week(-1), grade 1 bladder toxicity occurred in two of three patients. Dose escalation was stopped at 120 mg m(-2) week(-1). Cumulative bladder toxicity was dose-limiting toxicity at 80 mg m(-2) week(-1). Pharmacokinetics revealed highly variable urinary camptothecin excretion, associated with bladder toxicity. Due to cumulative bladder toxicity, weekly MAG-CPT is not a suitable regimen for treatment of patients with solid tumours

Antiarrhythmic and antioxidant activity of novel pyrrolidin-2-one derivatives with adrenolytic properties

A series of novel pyrrolidin-2-one derivatives (17 compounds) with adrenolytic properties was evaluated for antiarrhythmic, electrocardiographic and antioxidant activity. Some of them displayed antiarrhythmic activity in barium chloride-induced arrhythmia and in the rat coronary artery ligation-reperfusion model, and slightly decreased the heart rate, prolonged P–Q, Q–T intervals and QRS complex. Among them, compound EP-40 (1-[2-hydroxy-3-[4-[(2-hydroxyphenyl)piperazin-1-yl]propyl]pyrrolidin-2-one showed excellent antiarrhythmic activity. This compound had significantly antioxidant effect, too. The present results suggest that the antiarrhythmic effect of compound EP-40 is related to their adrenolytic and antioxidant properties. A biological activity prediction using the PASS software shows that compound EP-35 and EP-40 can be characterized by antiischemic activity; whereas, compound EP-68, EP-70, EP-71 could be good tachycardia agents

The clinical implications of sunitinib-induced hypothyroidism: a prospective evaluation

Sunitinib is approved for the treatment of metastatic renal cell carcinoma (RCC) and imatinib-resistant or -intolerant gastrointestinal stromal tumours (GIST). Several studies have identified unexpected rates of thyroid dysfunction with sunitinib treatment. We performed a prospective observational study with the aim of more accurately defining the incidence and severity of hypothyroidism in RCC or GIST patients receiving sunitinib. Thyroid function was assessed at baseline and on days 1 and 28 of each treatment cycle. Thyroid antibodies were assessed at baseline and during follow-up if abnormal thyroid function tests were recorded. Sixteen patients (27%) developed sub- or clinical hypothyroidism and required hormone replacement and 20 patients (34%) showed at least one elevated thyroid-stimulating hormone not requiring therapeutic intervention. Twenty patients (34%) did not develop any biochemical thyroid abnormality. Thus, sunitinib can induce (sub-) clinical hypothyroidism, warranting close monitoring of thyroid function. We propose a new algorithm for managing this side effect in clinical practise

SmCL3, a Gastrodermal Cysteine Protease of the Human Blood Fluke Schistosoma mansoni

Parasitic infection caused by blood flukes of the genus Schistosoma is a major global health problem. More than 200 million people are infected. Identifying and characterizing the constituent enzymes of the parasite's biochemical pathways should reveal opportunities for developing new therapies (i.e., vaccines, drugs). Schistosomes feed on host blood, and a number of proteolytic enzymes (proteases) contribute to this process. We have identified and characterized a new protease, SmCL3 (for Schistosoma mansoni cathepsin L3), that is found within the gut tissue of the parasite. We have employed various biochemical and molecular biological methods and sequence similarity analyses to characterize SmCL3 and obtain insights into its possible functions in the parasite, as well as its evolutionary position among cathepsin L proteases in general. SmCL3 hydrolyzes major host blood proteins (serum albumin and hemoglobin) and is expressed in parasite life stages infecting the mammalian host. Enzyme substrate specificity detected by positional scanning-synthetic combinatorial library was confirmed by molecular modeling. A sequence analysis placed SmCL3 to the cluster of other cathepsins L in accordance with previous phylogenetic analyses