Patchouli, tea tree, geranium, lavender essential oils and Citricidal (grapefruit seed extract) were used singly and in combination to assess their anti-bacterial activity against three strains of Staphylococcus aureus: Oxford S. aureus NCTC 6571 (Oxford strain), Epidemic methicillin-resistant S. aureus (EMRSA 15) and MRSA (untypable). The individual essential oils, extracts and combinations were impregnated into filter paper discs and placed on the surface of agar plates, pre-seeded with the appropriate strain of Staphylococcus. The effects of the vapours of the oils and oil combinations were also assessed using impregnated filter paper discs that were placed on the underside of the Petri dish lid at a distance of 8mm from the bacteria. The most inhibitory combinations of oils for each strain were used in a dressing model constructed using a four layers of dressings: the primary layer consisted of either Jelonet or TelfaClear with or without Flamazine; the second was a layer of gauze, the third a layer of Gamgee and the final layer was Crepe bandage. The oil combinations were placed in either the gauze or the Gamgee layer. This four-layered dressing was placed over the seeded agar plate, incubated for 24h at 37 degrees C and the zones of inhibition measured. All experiments were repeated on three separate occasions. No anti-bacterial effects were observed when Flamazine was smeared on the gauze in the dressing model. When Telfaclear was used as the primary layer in the dressing model compared to Jelonet, greater zones of inhibition were observed. A combination of Citricidal and geranium oil showed the greatest-anti-bacterial effects against MRSA, whilst a combination of geranium and tea tree oil was most active against the methicillin-sensitive S. aureus (Oxford strain). This study demonstrates the potential of essential oils and essential oil vapours as antibacterial agents and for use in the treatment of MRSA infection.

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Schwann cells are essential facilitators of peripheral nerve regeneration following injury, as they provide physical support and guidance. In vitro these supporting cells are slow-growing and hence are not well suited to a tissue-engineering approach to nerve repair. We have differentiated rat bone-marrow-derived mesenchymal stem cells into Schwann-cell-like cells using a cocktail of growth factors, including glial growth factor-2. Qualitative reverse transcription-PCR, Western-blotting and immunocytochemical approaches were used to investigate the mRNA transcript levels and protein expression of glial cell markers and neurotrophic factors in differentiated mesenchymal stem cells compared with the levels found in Schwann cells (which acted as a positive control). The results showed that differentiated mesenchymal stem cells expressed transcripts and proteins for the specific glial growth receptor 2, erbB3 and neurotrophic factors, nerve growth factor, brain-derived neurotrophic factor, glial-derived neurotrophic factor and leukaemia inhibitory factor. Expression of these growth factors provides further evidence that differentiated mesenchymal stem cells appear to have cellular and molecular characteristics similar to those of Schwann cells.

The developmental gene PAX 3 is expressed in the early embryo in developing muscle and elements of the nervous system, including the brain. Since no one has investigated the expression of the isoforms of PAX 3 in the neuroectodermal tumors melanoma and small cell lung cancer (SCLC), we have carried out a comprehensive screening for the expression of the isoforms PAX 3a-e using RT-PCR in human melanoma cell lines, primary human ocular and secondary cutaneous melanomas. We have identified 2 new isoforms of PAX 3, g and h, which we have isolated, cloned and sequenced. Sets of primers for each isoform were designed and their specificity was confirmed by sequence analysis of the products. The isoforms PAX 3a-e were detected in all human cutaneous melanoma cell lines (8/8), but only PAX 3c (1/2) and PAX 3d (2/2) in ocular melanoma cell lines. The same PAX 3 isoforms were detected in more than 80% of human cutaneous melanomas: PAX 3a and b (15/17), PAX 3c (14/17), PAX 3d (16/17) and PAX 3e (15/17). In contrast the results for 7 SCLC cell lines were PAX 3a (0/7), PAX 3b (1/7), PAX 3c (3/7), PAX 3d (6/7), PAX 3e (2/7); 8/8 cutaneous melanoma cell lines and 8/8 ocular melanoma tissues, together with 14/17 cutaneous melanoma tissues screened, expressed the new isoform PAX 3g. All 8 cutaneous melanoma cell lines expressed PAX 3h, but it was not detectable in any of the tumor tissues (0/20). Neither of the 2 ocular melanoma cell lines expressed the 2 new isoforms. Comparison of the different amplicon staining intensities on a gel suggests that PAX 3c and PAX 3d are the predominant transcripts expressed, with relatively low expression of PAX 3e and PAX 3h. We propose that these and the 2 new isoforms we have discovered may be important in oncogenesis and differential diagnosis of melanomas or SCLC.