Diverse gram-negative bacterial cells communicate with each other by using diffusible N-acyl homoserine lactone (AHL) signal molecules to coordinate gene expression with cell population density. Accumulation of AHLs above a threshold concentration renders the population “quorate,” and the appropriate target gene is activated. In pathogenic bacteria, such as Pseudomonas aeruginosa, AHL-mediated quorum sensing is involved in the regulation of multiple virulence determinants. We therefore sought to determine whether the immune system is capable of responding to these bacterial signal molecules. Consequently the immunomodulatory properties of the AHLsN-(3-oxododecanoyl)-l-homoserine lactone (OdDHL) and N-(3-oxohexanoyl)-l-homoserine lactone (OHHL) were evaluated in murine and human leukocyte immunoassays in vitro. OdDHL, but not OHHL, inhibited lymphocyte proliferation and tumor necrosis factor alpha production by lipopolysaccharide-stimulated macrophages. Furthermore, OdDHL simultaneously and potently down-regulated the production of IL-12, a Th-1-supportive cytokine. At high concentrations (>7 × 10−5 M) OdDHL inhibited antibody production by keyhole limpet hemocyanin-stimulated spleen cells, but at lower concentrations (<7 × 10−5 M), antibody production was stimulated, apparently by increasing the proportion of the immunoglobulin G1 (IgG1) isotype. OdDHL also promoted IgE production by interleukin-4-stimulated human peripheral blood mononuclear cells. These data indicate that OdDHL may influence the Th-1–Th-2 balance in the infected host and suggest that, in addition to regulating the expression of virulence determinants, OdDHL may contribute to the pathogenesis of P. aeruginosa infections by functioning as a virulence determinant per se.

Traditional medicine refers to health practices, approaches, knowledge and beliefs incorporating plant, animal and mineral based medicines, spiritual therapies, manual techniques and exercises, applied singularly or in combination to treat, diagnose and prevent illnesses or maintain well-being. In the last decade traditional medicine has become very popular in Cameroon, partly due to the long unsustainable economic situation in the country. The high cost of drugs and increase in drug resistance to common diseases like malaria, bacteria infections and other sexually transmitted diseases has caused the therapeutic approach to alternative traditional medicine as an option for concerted search for new chemical entities (NCE). The World Health Organisation (WHO) in collaboration with the Cameroon Government has put in place a strategic platform for the practice and development of TM in Cameroon. This platform aims at harmonizing the traditional medicine practice in the country, create a synergy between TM and modern medicine and to institutionalize a more harmonized integrated TM practices by the year 2012 in Cameroon. An overview of the practice of TM past, present and future perspectives that underpins the role in sustainable poverty alleviation has been discussed. This study gives an insight into the strategic plan and road map set up by the Government of Cameroon for the organisational framework and research platform for the practice and development of TM, and the global partnership involving the management of TM in the country.

Poly(vinyl alcohol) (PVA) is a water-soluble, biocompatible and biodegradable polymer, which has been widely applied in biomedical fields. In this paper, novel physically cross-linked hydrogels composed of PVA and comprising a blend of poly(vinyl alcohol) (PVA) with different concentrations of HCl, NaOH and NaCl are prepared by a freezing/thawing treatment of aqueous solutions. The structure and complexation of the electrolytes were studied by Fourier transform infrared (FTIR) spectroscopy. The mechanical properties were investigated using rheometery and the thermal transitions of the hydrogels were examined by modulated differential scanning calorimetry (MDSC). Freeze/thawed PVA gels containing NaOH showed overall enhanced swelling with increased mechanical strength over traditional gels prepared by chemical or irradiative crosslinking techniques. These novel physically cross-linked hydrogels show promise for a variety of biomedical and drug delivery applications.

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RT-PCR produced consistent results, indicating that this technique could be used to investigate the effect of biological mediators and novel pharmacological agents on cytokine mRNA levels in macrophages.