Leo Salter

The green tea polyphenol (-)-epigallocatechin gallate and green tea can protect human cellular DNA from ultraviolet and visible radiation-induced damage.

Background: Antioxidant compounds in green tea may be able to protect against skin carcinogenesis and it is of interest to investigate the mechanisms involved. A study was therefore conducted to determine whether the isolated green tea polyphenol (−)‐epigallocatechin gallate (EGCG) could prevent ultraviolet radiation (UVR)‐induced DNA damage in cultured human cells. This work was then extended to investigate whether drinking green tea could afford any UVR protection to human peripheral blood cells collected after tea ingestion.

Photodynamic therapy using meta‐tetrahydroxyphenylchlorin (Foscan®) for the treatment of vulval intraepithelial neoplasia

Background  Photodynamic therapy (PDT) has unique properties which make it suitable for the local treatment of superficial epithelial disorders; it has been suggested as a useful treatment for carcinoma in situ of the vulva.

A preliminary investigation of the effects of arsenate on irradiation-induced DNA damage in cultured human lung fibroblasts.

Single-cell gel electrophoresis (the comet assay) was used to assess single-strand breaks (SSBs) produced in cultured lung human fibroblasts by xenon lamp irradiation alone, various concentrations of arsenate [As(V)], alone or various combinations of the two. It was found that significantly higher levels of SSBs were observed in the irradiated cells than the nonirradiated cells and that elevating levels of arsenate enhanced the level of damage detected in both irradiated and nonirradiated cells in a concentration-dependent manner; that is, incubating cells with arsenate alone produced marked DNA damage without an irradiation insult being necessary. The results of this study indicate that arsenate is acting as a cogenotoxin with irradiation in this cell line. This additive effect may also be cocarcinogenic, and as a result it is possible that less solar irradiation may be required to induce skin cancer in arsenic-exposed populations.

Hg(II) Exposure Exacerbates UV-Induced DNA Damage in MRC5 Fibroblasts: A Comet Assay Study

When exposed to UVR, MRC5 fibroblasts incubated with mercuric chloride (0–15 μM) for 1 hour show increased DNA damage (as measured by the comet assay) compared to control cells (UVR irradiated but no mercuric chloride). This demonstrates that mercuric chloride and UVR in combination increase DNA damage in a synergistic manner. This may have implications to those exposed to mercury as it suggests that exposure to mercury in the environment may increase sensitivity to sunlight-induced carcinogenesis.

A PRELIMINARY INVESTIGATION OF OZONE CONCENTRATIONS ON THE LIZARD PENINSULA CORNWALL, U.K. USING CONTINUOUS MONITORING AND DIFFUSION TUBES

The Lizard Peninsula is an isolated area of unique and sensitive ecology and the occurrence of damaging ozone concentrations over the peninsula in spring challenges the successful sustainable management of the area. Ozone concentrations over Goonhilly Downs on the Lizard Peninsula in Cornwall were measured in spring 2002 using continuous monitoring and spatial mapping (diffusion tubes). Data obtained using a continuous ozone monitor (1/03/02 to 31/03/02) showed that the AOT40 5-day values were in a range from 2 to 800 μg m-3 hr (AOT40 is the sum of the differences between the measured hourly ozone concentration (μg m-3) and 80 μg m-3 (when the concentration exceeds 80 μg m-3) for the hours when global radiation exceeds 50 Wm-2). Contour mapping of ozone concentrations measured with diffusion tubes suggested that over a 2 km2 sampling area significant microscale variations were occurring with ozone concentrations ranging between 48–129 μg m-3 for one two-week period and 62–210 μg m-3 for the other.Unusually high diurnal variations in ozone concentrations were also observed at Goonhilly. It is thought that temperature inversions caused the entrapment of ozone at the surface level.

The Effect of Distant Sources of Ozone and PM10s on Boundary Layer Air Quality in Cornwall — a rural area in the UK

Cornwall is an isolated rural area in the far south-west peninsula of the UK (EA, 2001) — see Figure One, Frequent ventilation of the peninsula with atlantic air suggests that air quality in Cornwall should be good. However, because of significant contributions from distant sources, boundary layer concentrations of ozone and airborne particulate matter (PM10S) can exceed the objectives set by the UK National Air Quality Strategy (NAQS) viz. Ozone: 50 ppb as a daily maximum of running 8-hour means (1999) (not now included in the NAQS due to contributions by transboundary influences), PM10: 50 μg m−3 as a running 24-hour average, (DETR, 2000).

An Investigation of the Genotoxic Effects of Airborne Particulate Matter Using Single-Cell Gel Electrophoresis

Samples of the PM 10 fraction of airborne particulate mat ter were collected from a roadside location in Cornwall using a Partisol 2000 gravimetric air sampler. Cultured human lung fibroblasts were exposed to a sonicated extract of this matter for various periods of time (0-120 h) and the presence of DNA damage was then assessed using single-cell gel electrophoresis. Four times the level of DNA damage was detected in the PM10-exposed cells than that observed in similarly treated but non-PM10 exposed control cells. This indicates that the airborne PM10 from this site has significant genotoxic effects in this experimental system and that single-cell gel electro phoresis is a useful technique for the assessment of this form of particulate matter-induced biological damage.