An efficient method to determine the Hydrophile-Lipophile Balance of surfactants using the phase inversion temperature deviation of Ci Ej /n-octane/water emulsions.

OBJECTIVE: The aim of this study was to develop a fast and an efficient method to determine the Hydrophile-Lipophile Balance (HLB) number of cosmetic and pharmaceutics surfactants. METHODS: This method is based on the deviation of the phase inversion temperature induced by the addition of the test compound, with respect to the phase inversion temperature of a reference system, which includes an ethoxylated surfactant. This method is called PIT-deviation. RESULTS: Three calibration curves are set up with three reference ethoxylated surfactants. These calibration curves make it possible to evaluate the interfacial behaviour of certain chemicals. More particularly, these curves make it possible to easily determine the surfactant HLB. CONCLUSION: In this study, a fast and accurate method has been developed to determine the hydrophilic-lipophilic balance (HLB) number of amphiphilic chemicals. This new method can be applied to establish an HLB number of all commercial amphiphilic ingredients. Compounds which have a PIT-deviation close to zero are also discussed.

OBJECTIF: Le but de cette étude était de développer une méthode rapide et efficace pour déterminer le nombre Hydrophiles-Lipophiles Balance (HLB) d'agents tensioactifs cosmétiques et pharmaceutiques. MÉTHODES: Cette méthode est basée sur le déplacement de la température d'inversion de phase induite par l'addition du composé à tester par rapport à la température d'inversion de phase d'un système de référence, comprenant un tensioactif éthoxylé. Cette méthode s'appelle PIT-déviation. RÉSULTATS: Trois courbes d'étalonnage sont établies avec trois tensioactifs éthoxylés de référence. Ces courbes d'étalonnage permettent d'évaluer le comportement interfacial de certains produits chimiques. Plus particulièrement, ces courbes permettent de déterminer facilement le HLB de tensioactif. CONCLUSION: Dans cette étude, une méthode rapide et précise a été développée pour déterminer le Hydrophile-Lipophile Balance (HLB) de produits chimiques amphiphiles. Cette nouvelle méthode peut être appliquée pour établir un HLB de tous les ingrédients amphiphiles. Les composés dont la PIT-deviation est proche de zéro sont également abordés.

Targeting soluble CD146 with a neutralizing antibody inhibits vascularization, growth and survival of CD146-positive tumors.

CD146 (MUC-18, MCAM) expression on cancer cells correlates with cancer progression and a bad prognosis in several tumors, including melanoma and pancreatic tumors. Deciphering the mechanism mediating the CD146 role in cancer is essential for generating new therapeutic strategies. We found that CD146 expression in cancer cells is associated with a secretion of soluble CD146 (sCD146) that constitutes an active player in tumor development. Indeed, sCD146 induces the overexpression of its binding protein, angiomotin, on both endothelial and cancer cells and promotes both paracrine effects on angiogenesis and autocrine effects on cancer cells proliferation and survival. These last effects are mediated in part through the induction and phosphorylation of c-myc in cancer cells. In mice models xenografted with human CD146-positive melanoma or pancreatic cancer cells, administration of a novel monoclonal antibody specifically targeting sCD146, but not its membrane form, successfully suppresses tumor vascularization and growth. Our findings demonstrate that sCD146 secreted by CD146-positive tumors mediates important pro-angiogenic and pro-tumoral effects. Targeting sCD146 with a novel neutralizing antibody could thus constitute an innovative therapeutic strategy for the treatment of CD146-positive tumors.

n-3 polyunsaturated fatty acid supplementation reverses stress-induced modifications on brain monoamine levels in mice.

The aim of this study was to examine the effects of supplementation with n-3 polyunsaturated fatty acids (PUFAs) on stress responses in mice subjected to an unpredictable chronic mild stress (UCMS) procedure. Stress-induced modifications in coat and aggressiveness were evaluated, and phospholipid PUFA profiles and monoamine levels were analyzed in the frontal cortex, hippocampus, and striatum. The results showed that repeated exposure to mild stressors induced degradation in the physical state of the coat, lowered body weight gain, and increased aggressiveness, without any effect of n-3 PUFA supplementation. The UCMS induced a significant decrease in the levels of norepinephrine in the frontal cortex and striatum, and a nonsignificant decrease in the hippocampus. The tissue levels of serotonin (5-HT) were 40% to 65% decreased in the three brain regions studied. Interestingly, the n-3 PUFA supplementation reversed this stress-induced reduction in 5-HT levels. These findings showed that supplementation in n-3 long-chain PUFAs might reverse certain effects of UCMS in cerebral structures involved in stress-related behaviors.

Absolute Intensities of the Infrared Bands of Gaseous Acrylonitrile.

Laboratory spectral data (peak positions and integrated band intensities) of the infrared bands of acrylonitrile (CH2CHCN) gas in the region 4000-220 cm-1 are presented. Even though CH2CHCN has not yet been identified in Titan's atmosphere, it is among the possible photochemical and cosmic irradiation products of CH4 + N2 chemistry in the atmosphere of Titan. Laboratory simulations of Titan's atmospheric chemistry also give CH2CHCN as a product species. The results of our evaluation of the infrared intensity data provide an upper limit of the stratospheric abundance of CH2CHCN. Copyright 1999 Academic Press.

Immunohistochemical detection of bcl-2 protein in normal and pathological human liver.

The bcl-2 protein, which prolongs cell survival by blocking apoptosis, is expressed by progenitor cells in several self-renewing tissues and by tumoral cells in some extrahepatic neoplasms. Because the liver is a slow self-renewing tissue, an immunohistochemical study of the cellular distribution of the bcl-2 protein was performed in normal liver (12 cases), nontumoral hepatic lesions (33 cases), and benign or malignant liver tumors (46 cases). In normal liver, bcl-2 was expressed by bile ductules and small bile duct epithelium, but not by hepatocytes or large bile duct epithelium. In cirrhosis and focal nodular hyperplasia, epithelial cells of the ductular proliferation were bcl-2-positive. Eight of 11 cholangiocarcinomas stained positively for bcl-2, whereas all 15 hepatocellular carcinomas were bcl-2-negative. bcl-2 was also expressed in 6 of 14 metastatic adenocarcinomas. These findings suggest that the ductular cells and small bile duct epithelial cells might have a prolonged survival and might be hepatic progenitor cells. In addition, the bcl-2 protein appears to be a marker of cholangiocarcinoma but not of hepatocellular carcinoma and could help in distinguishing between these two primary liver tumors.