Antibacterial and dermal toxicological profiles of ethyl acetate extract from Crassocephalum bauchiense (Hutch.) Milne-Redh (Asteraceae)

<p>Abstract</p> <p>Background</p> <p>The emergence in recent years of numerous resistant strains of pathogenic bacteria to a range of formerly efficient antibiotics constitutes a serious threat to public health. <it>Crassocephalum bauchiense</it>, a medicinal herb found in the West Region of Cameroon is used to treat gastrointestinal infections as well as liver disorders. The ethyl acetate extract from the leaves of <it>C. bauchiense </it>was evaluated for its antibacterial activity as well as acute and sub-acute toxicities.</p> <p>Methods</p> <p>The plant extract was prepared by maceration in ethyl acetate. Its phytochemical screening was done by standard methods. The broth microdilution method was used to evaluate the <it>in vitro </it>antibacterial activity. The <it>in vivo </it>antibacterial activity of a gel formulation (0.05, 1 and 2% w/v) of this extract was evaluated using a <it>Staphylococcus aureus</it>-induced dermatitis in a murine model. Selected haematological and biochemical parameters were used to evaluate the dermal sub-acute toxicity of the extract in rats.</p> <p>Results</p> <p>Phytochemical screening of the <it>C. bauchiense </it>extract revealed the presence of alkaloids, phenols, tannins and sterols. <it>In vitro </it>antibacterial activities were observed against all the tested microorganisms (MIC = 0.04-6.25 mg/ml). Formulated extract-gel (2% w/v) and gentamycin (reference drug) eradicated the microbial infection after five days of treatment. A single dermal dose of this extract up to 32 g/kg body weight (bw) did not produce any visible sign of toxicity. Also, daily dermal application of the <it>C. bauchiense </it>extract gel formulation for 28 days did not show any negative effect, instead some biochemical parameters such as alanine aminotransferase (ALT and AST), low density lipoprotein (LDL), high density lipoprotein (HDL) and triglycerides were significantly (p < 0.05) affected positively.</p> <p>Conclusion</p> <p>These results indicate that the <it>C. bauchiense </it>ethyl acetate extract can be used safely for the treatment of some bacterial infections.</p

Invading Basement Membrane Matrix Is Sufficient for MDA-MB-231 Breast Cancer Cells to Develop a Stable In Vivo Metastatic Phenotype

1 - ArticleIntroduction: The poor efficacy of various anti-cancer treatments against metastatic cells has focused attention on the role of tumor microenvironment in cancer progression. To understand the contribution of the extracellular matrix (ECM) environment to this phenomenon, we isolated ECM surrogate invading cell populations from MDA-MB-231 breast cancer cells and studied their genotype and malignant phenotype. Methods: We isolated invasive subpopulations (INV) from non invasive populations (REF) using a 2D-Matrigel assay, a surrogate of basal membrane passage. INV and REF populations were investigated by microarray assay and for their capacities to adhere, invade and transmigrate in vitro, and to form metastases in nude mice. Results: REF and INV subpopulations were stable in culture and present different transcriptome profiles. INV cells were characterized by reduced expression of cell adhesion and cell-cell junction genes (44% of down regulated genes) and by a gain in expression of anti-apoptotic and pro-angiogenic gene sets. In line with this observation, in vitro INV cells showed reduced adhesion and increased motility through endothelial monolayers and fibronectin. When injected into the circulation, INV cells induced metastases formation, and reduced injected mice survival by up to 80% as compared to REF cells. In nude mice, INV xenografts grew rapidly inducing vessel formation and displaying resistance to apoptosis. Conclusion: Our findings reveal that the in vitro ECM microenvironment per se was sufficient to select for tumor cells with a stable metastatic phenotype in vivo characterized by loss of adhesion molecules expression and induction of proangiogenic and survival factors

Trophic macrophages in development and disease

Specialized phagocytes are found in the most primitive multicellular organisms. Their roles in homeostasis and in distinguishing self from non-self have evolved with the complexity of organisms and their immune systems. Equally important, but often overlooked, are the roles of macrophages in tissue development. As discussed in this Review, these include functions in branching morphogenesis, neuronal patterning, angiogenesis, bone morphogenesis and the generation of adipose tissue. In each case, macrophage depletion impairs the formation of the tissue and compromises its function. I argue that in several diseases, the unrestrained acquisition of these developmental macrophage functions exacerbates pathology. For example, macrophages enhance tumour progression and metastasis by affecting tumour-cell migration and invasion, as well as angiogenesis

Structure and mechanical and corrosion properties of new high-nitrogen Cr-Mn steels containing molybdenum

The structure, mechanical properties, and pitting corrosion of nickel-free high-nitrogen (0.8% N) austenitic 06Kh18AG19M2 and 07Kh16AG13M3 steels have been studied in various structural states obtained after hot deformation, quenching, and tempering at 300 and 500°C. Both steels are shown to be resistant to the γ → α and γ → e{open} martensite transformations irrespective of the decomposition of a γ solid solution (06Kh18AG19M2 steel). Austenite of the steel with 19 wt% Mn shows lower resistance to recrystallization, which provides its higher plasticity (δ 5) and fracture toughness at a lower strength as compared to the steel with 13 wt% Mn. Electrochemical studies of the steels tempered at 300 and 500°C show that they are in a stable passive state during tests in a 3.5% NaCl solution and have high pitting resistance up to a potential E pf = 1.3-1.4 V, which is higher than that in 12Kh18N10T steel. In the quenched state, the passive state is instable but pitting formation potentials E pf retain their values. In all steels under study, pitting is shown to form predominantly along the grain boundaries of nonrecrystallized austenite. The lowest pitting resistance is demonstrated by the structure with a double grain boundary network that results from incomplete recrystallization at 1100°C and from the existence of initial and recrystallized austenite in the 07Kh16AG13M3 steel. To obtain a set of high mechanical and corrosion properties under given rolling conditions (1200-1150°C), annealing of the steels at temperatures no less than 1150°C (for 1 h) with water quenching and tempering at 500°C for 2 h are recommended. © 2012 Pleiades Publishing, Ltd