Effect of zein additive on perfume evaporation.

OBJECTIVE: Zein is known to have filmogen properties. We wanted to show if a zein film containing eugenol (eugenol as model) would retain the fragrances, slow their evaporation and therefore produce a long-lasting perception of perfume. METHODS: We added corn zein to eugenol in a hydro-alcoholic solution to form a film in vitro and at the surface of the human skin. We have studied the trapping and release of eugenol from zein film by GC/MS. Also we labelled eugenol with deuterium to image specifically its distribution in the zein film using Secondary Ion Mass Spectrometry technique (NanoSIMS 50). Finally, we applied the zein/D-eugenol formulation onto skin to image the eugenol location on and in skin by SIMS (Secondary Ion Mass Spectrometry). RESULTS: We showed that eugenol evaporation from zein film can be divided in three periods. The first period (≤2 h) corresponds to the simultaneous solvent and eugenol evaporation occurring during film formation. The second period corresponds to the continuous and slow eugenol evaporation during a few hours (about 10 h) but not to its completion. The third period (at least up to 48 h) results from the trapping of eugenol in zein film. After 24 or 48 h, trapped eugenol can be released and evaporated under mechanical deformations of the film. Moreover we showed that zein addition does not favour the eugenol penetration into viable epidermis which may cause allergenic cutaneous reaction. CONCLUSION: The zein additive is safe to use, does not impact the olfactory perception, allows a better perception of the fragrance (long-lasting effect) in a more protective way and can be used in perfume.

Prevalence and characterization of extended-spectrum ß-lactamase-producing clinical Salmonella enterica isolates in Dakar, Senegal, from 1999 to 2009.

A total of 1623 clinical isolates of Salmonella belonging to 229 serotypes were received by the Senegalese Reference Center for Enterobacteria from January 1999 to December 2009. The most common serotypes were Enteritidis (19% of the isolates), Typhi (8%), Typhimurium (7%) and Kentucky (4%). A significant increase in the prevalence of resistance to amoxicillin (0.9% in 1999 to 11.1% in 2009) and nalidixic acid (0.9% in 1999 to 26.7% in 2009) was observed in non-typhoidal Salmonella serotypes. For critically important antibiotics, notably ciprofloxacin and extended-spectrum cephalosporins (ESCs), the rates of resistance were low: 0.3% and 0.5%, respectively. Seven ESC-resistant Salmonella strains and three additional ESC-resistant strains from Senegal (1990) and Mali (2007) were studied to identify the genetic basis of their antibiotic resistance. All ESC-resistant strains produced an extended-spectrum ß-lactamase (ESBL). These were CTX-M-15 (n = 6; 2000-2008), SHV-12 (n = 3; 2000-2001) and SHV-2 (n = 1; 1990). A large IncHI2 ST1 pK29-like plasmid was found in six strains (three producing SHV-12 and three CTX-M-15), whereas IncN and IncF plasmids were found in three strains and one strain, respectively. The association of plasmid-mediated quinolone resistance (PMQR) genes qnrB1 and aac(6')-Ib-cr was found in four ESBL-producing strains, leading to decreased susceptibility and even full resistance to ciprofloxacin (MIC range 0.75-2 mg/L) despite the absence of mutations in the quinolone resistance-determining region (QRDR) of gyrA, gyrB, parC and parE. This association of ESBL and multiple PMQR mechanisms within the same strains is therefore a serious concern as it hampers the use of both ESCs and fluoroquinolones for severe Salmonella infections.

Importance of ERK activation in As2O3-induced differentiation and promyelocytic leukemia nuclear bodies formation in neuroblastoma cells.

Neuroblastoma malignant cell growth is dependent on their undifferentiated status. Arsenic trioxide (As2O3) induces neuroblastoma cell differentiation in vitro, but its mechanisms still remains unknown. We used three human neuroblastoma cell lines (SH-SY5Y, IGR-N-91, LAN-1) that differ from their MYCN and p53 status to explore the intracellular events activated by As2O3 and involved in neurite outgrowth, a morphological marker of differentiation. As2O3 (2µM) induced neurite outgrowth in all cell lines, which was dependent on ERK activation but independent on MYCN status. This process was induced either by a sustained (3 days) or a transient (2h) incubation with As2O3, indicating that very early events trigger the induction of differentiation. In parallel, As2O3 induced a rapid assembly of promyelocytic leukemia nuclear bodies (PML-NB) in an ERK-dependent manner. In conclusion, mechanisms leading to neuroblastoma cell differentiation in response to As2O3 appear to involve the ERK pathway activation and PML-NB formation, which are observed in response to other differentiating molecules such as retinoic acid derivates. This open new perspectives based on the use of treatment combinations to potentiate the differentiating effects of each drug alone and reduce their adverse side effects.

Method for macromolecular colocalization using atomic recombination in dynamic SIMS.

Localizing two or more components of assemblies in biological systems requires both continued development of fluorescence techniques and invention of entirely new techniques. Candidates for the latter include dynamic secondary ion mass spectrometry (D-SIMS). The latest generation of D-SIMS, the Cameca NanoSIMS 50, permits the localization of specific, isotopically labeled molecules and macromolecules in sections of biological material with a resolution in the tens of nanometers and with a sensitivity approaching in principle that of a single protein. Here we use two different systems, crystals of glycine and mixtures of proteins, to show that the formation of recombinant CN secondary ions under Cs bombardment can be exploited to create a new colocalization technique. We show experimentally that the formation of the recombinant (13)C(15)N secondary ion between (13)C- and (15)N-labeled macromolecules is indeed an indicator of the distance between the interacting macromolecules and on their shape. We build up a convolution model of the mixing-recombination process in D-SIMS that allows quantitative interpretations of the distance-dependent formation of the recombinant CN. Our results show that macromolecules can be colocalized if they are within 2 nm of one another. We discuss the potential advantages of this new technique for biological applications.

Promyelocytic leukemia-nuclear body formation is an early event leading to retinoic acid-induced differentiation of neuroblastoma cells.

Neuroblastoma is one of the most common cancers in children. Neuroblastoma differentiation is linked to the presence of the promyelocytic leukemia (PML) protein. Retinoic acid, a powerful differentiation-inducer in vitro, is a potent agent for the treatment of neuroblastoma. Using two different human neuroblastoma cell lines, SH-SY5Y and LA-N-5, we show here that PML protein leads to the formation of nuclear bodies (PML-NB) after only 1 h of retinoic acid treatment and that this formation is mediated by the extracellular signal-regulated kinase (ERK) pathway. Inhibition of protein kinase C also leads to formation of PML-NB via the ERK pathway. Both sumoylation and phosphorylation of PML in an ERK-dependent pathway are also required for formation of PML-NB. Finally, we show that PML-NB formation in neuroblastoma cells is associated with neurite outgrowth. These results support the proposal that the formation of PML-NB is correlated with the differentiation of neuroblastoma cells.