Activation of HTLV-I transcription in the presence of Tax is independent of the acetylation of CREB-2 (ATF-4).

We have previously demonstrated that the bZIP transcription factor CREB-2, also called ATF-4, trans-activates, in association with the viral protein Tax, the human T-cell leukemia virus type I (HTLV-I) promoter. In this study, we have examined whether CREB-2 acetylation affects transcriptional activation mediated by Tax. We present evidence that CREB-2 is acetylated in vitro and in vivo. CREB-2 is acetylated in two regions: the basic domain of the bZIP (from amino acid residue 270 to 300) and the short basic domain (from 342 to 351) located downstream from the bZIP. We also demonstrate that CREB-2 is acetylated by p300/CBP but not by p/CAF. Moreover, replacement of lysine by arginine in the basic domains decreases the trans-activating capacity of CREB-2. However, in the presence of Tax, the HTLV-I transcription remains fully activated by these CREB-2 mutants. Although we cannot totally exclude that the mutations could also affect CREB-2 structure and activity independent of acetylation, our results suggest that activation of the viral promoter in the presence of Tax is independent of the CREB-2 acetylation.

Pédiatrie. 4. La calprotectine fécale en pédiatrie: utilisation et interprétation [Pediatrics. Fecal calprotectin in children: use and interpretation].

Fecal calprotectin is a small protein released mainly by neutrophils. It is recognized as a reliable, easy and non-invasive biomarker of gastro-intestinal inflammation. Normal values vary with age, with higher cut-off values during the first year of life (<350 microg/g) than in children (<275 microg/g) or adults (<50 microg/g). Fecal calprotectin can be a useful tool in initial evaluation of recurrent abdominal pain, helping to distinguish between functional gastro-intestinal disorders, where it is normal, and inflammatory bowel disease (IBD). It is not a specific marker of IBD but is increased in other situations of gastro-intestinal inflammation. In patients with IBD, fecal calprotectin is used to monitor treatment response.

Interleukin-4 (IL-4) and interferon-gamma (IFN-gamma) in pregnant C57BL/6 mice infected with L. major at different gestational periods.

BACKGROUND AND OBJECTIVE: To assess if gestational factors affect the resistance of C57BL/6 mice to L major infection, this study determined the levels of IL-4 and IFN-gamma in popliteal lymph node cells of pregnant C57BL/6 mice infected with L. major at 16 hours, 5 days-, 10 days- and 15 days- post plug by PCR, ELISA and BIOASSAY. DESIGN/SETTING: Experimental. RESULTS: Infected pregnant C57BL/6 mice developed larger cutaneous footpad lesions compared with non-pregnant C57BL/6 mice (that showed signs of resolution 7-10 weeks after infection). But, the lesions in infected pregnant C57BL/6 mice and infected non-pregnant C57BL/6 mice were not as large as in susceptible BALB/c mice. The mean litter weight was also reduced in pregnant infected C57BL/6 mice particularly in the groups infected at later stages of pregnancy (day 10- and day 15-post plug). The levels of both IL-4 and IFN-gamma increased with gestation in pregnant infected C57BL/6 mice compared with pregnant non-infected group, while only IL-4 was raised in pregnant infected mice compared with infected non pregnant mice. CONCLUSIONS: It may be concluded that increased IL-4 in pregnant infected C57BL/6 mice caused the transient susceptibility to L major infection while reduced litter weight was associated with increased IFN-gamma. These effects were pronounced in C57BI/6 mice infected with L major in late pregnancy.

Atypical teratoid/rhabdoid tumor of the spine in a 4-year-old girl.

Primary spinal atypical teratoid/rhabdoid tumor is extremely rare. The authors present a case of atypical teratoid/rhabdoid tumor occurring in a 4-year-old girl. Magnetic resonance imaging The authors showed an intramedullary mass extending from the bulbomedullary junction to T1 with leptomeningeal dissemination. The patient died 2 weeks after diagnosis.

Phase I and phase II xenobiotic reactions and metabolism of the food-borne carcinogen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline in aggregating liver cell cultures.

Aggregating fetal liver cell cultures were tested for their ability to metabolize xenobiotics using ethoxycoumarin-O-deethylase (ECOD), as marker of phase I metabolism, and glutathione S-transferase (GST), as marker for phase II reactions. Significant basal activities, stable over 14 days in culture were measured for both ECOD and GST activities. The prototype cytochrome P450 inducers, 3-methylcholanthrene (3-MC) and phenobarbital (PB), increased ECOD and GST activities reaching an optimum 7 days after culturing, followed by a decline in activity. This decline was partially prevented by 1% dimethyl sulfoxide (DMSO) added chronically to the culture medium. DMSO was also found to induce ECOD activity and to a lesser extent GST activity. Furthermore, it potentiated in a dose-dependent manner the induction of ECOD by PB. The food-borne carcinogen 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) is metabolically transformed through a number of pathways in vivo. It was therefore used to examine the metabolic capacity in fetal and adult liver cell aggregates. Metabolism of MeIQx was mainly through N2-conjugation, resulting in formation of the N2-glucuronide and sulfamate conjugates for non-induced fetal liver cells. These metabolites were also found in large amounts in non-induced adult liver cells. Low levels of cytochrome P450-mediated ring-hydroxylated metabolites were detected in both non-induced fetal and adult liver cells. After induction with arochlor (PCB) or 3-MC, the major pathway was ring-hydroxylation (cytochrome P450 dependent), followed by conjugation to beta-glucuronic or sulfuric acid. The presence of the glucuronide conjugate of N-hydroxy-MeIQx, a mutagenic metabolite, suggested an induction of P450 CYP1A2. The metabolism of MeIQx by liver cell aggregates is very similar to that observed in vivo and suggests that aggregating liver cell cultures are a useful model for in vitro metabolic studies in toxicology.

Phosphatidylinositol 4,5-bisphosphate clusters act as molecular beacons for vesicle recruitment.

Synaptic-vesicle exocytosis is mediated by the vesicular Ca(2+) sensor synaptotagmin-1. Synaptotagmin-1 interacts with the SNARE protein syntaxin-1A and acidic phospholipids such as phosphatidylinositol 4,5-bisphosphate (PIP2). However, it is unclear how these interactions contribute to triggering membrane fusion. Using PC12 cells from Rattus norvegicus and artificial supported bilayers, we show that synaptotagmin-1 interacts with the polybasic linker region of syntaxin-1A independent of Ca(2+) through PIP2. This interaction allows both Ca(2+)-binding sites of synaptotagmin-1 to bind to phosphatidylserine in the vesicle membrane upon Ca(2+) triggering. We determined the crystal structure of the C2B domain of synaptotagmin-1 bound to phosphoserine, allowing development of a high-resolution model of synaptotagmin bridging two different membranes. Our results suggest that PIP2 clusters organized by syntaxin-1 act as molecular beacons for vesicle docking, with the subsequent Ca(2+) influx bringing the vesicle membrane close enough for membrane fusion.

Effects of the α₂-adrenergic agonist clonidine on the pharmacodynamics and pharmacokinetics of 3,4-methylenedioxymethamphetamine in healthy volunteers.

The mechanism of action of 3,4-methylenedioxymethamphetamine (MDMA; ecstasy) involves the carrier-mediated and potentially vesicular release of monoamines. We assessed the effects of the sympatholytic α₂-adrenergic receptor agonist clonidine (150 μg p.o.), which inhibits the neuronal vesicular release of norepinephrine, on the cardiovascular and psychotropic response to MDMA (125 mg p.o.) in 16 healthy subjects. The study used a randomized, double-blind, placebo-controlled crossover design with four experimental sessions. The administration of clonidine 1 h before MDMA reduced the MDMA-induced increases in plasma norepinephrine concentrations and blood pressure but only to the extent that clonidine lowered norepinephrine levels and blood pressure compared with placebo. Thus, no interaction was found between the cardiovascular effects of the two drugs. Clonidine did not affect the psychotropic effects or pharmacokinetics of MDMA. The lack of an interaction of the effects of clonidine and MDMA indicates that vesicular release of norepinephrine, which is inhibited by clonidine, does not critically contribute to the effects of MDMA in humans. Although clonidine may be used in the treatment of stimulant-induced hypertensive reactions, the present findings do not support a role for α₂-adrenergic receptor agonists in the prevention of psychostimulant dependence.

The use of the murine model of infection with Leishmania major to reveal the antagonistic effects that IL-4 can exert on T helper cell development and demonstrate that these opposite effects depend upon the nature of the cells targeted for IL-4 signaling.

In contrast to mice from the majority of inbred strains, BALB mice develop aberrant Th2 responses and suffer progressive disease after infection with Leishmania major. These outcomes depend on the production of Interleukin 4, during the first 2 d of infection, by CD4+ T cells that express the Vbeta4-Valpha8 T cell receptors specific for a dominant I-A(d) restricted epitope of the LACK antigen from L. major. In contrast to this well established role of IL-4 in Th2 cell maturation, we have recently shown that, when limited to the initial period of activation of dendritic cells by L. major preceding T cell priming, IL-4 directs DCs to produce IL-12, promotes Th1 cell maturation and resistance to L. major in otherwise susceptible BALB/c mice. Thus, the antagonistic effects that IL-4 can have on Th cell development depend upon the nature of the cells (DCs or primed T cells) targeted for IL-4 signaling.