Bruce P. Dunn

Clastogenic activity of caffeic acid and its relationship to hydrogen peroxide generated during autooxidation.

Caffeic acid is a clastogenic cinnamic acid found in a conjugated form in a variety of foods. The possibility that the biological activity of caffeic acid is due to hydrogen peroxide generated during its autooxidation in solution was investigated using chromosome aberrations in Chinese hamster ovary cells as a test system. Freshly prepared caffeic acid at pH 7.00 contained only traces of hydrogen peroxide, as assayed by the molybdate-catalyzed release of I-3. Such solutions exhibited clastogenic activity which could not be accounted for by the level of hydrogen peroxide present, and which was not significantly diminished by the addition of catalase or horseradish peroxidase. 3-day-old solutions of caffeic acid exhibited higher levels of hydrogen peroxide, and increased biological activity. In such solutions, the clastogenic activity was catalase-sensitive and could be entirely accounted for by the level of hydrogen peroxide present.

Release of the carcinogen benzo (a) pyrene from environmentally contaminated mussels.

The release of B(a)P from contaminated mussels on transfer from a polluted area to tanks with clean circulating seawater was measured using fluorescence spectroscopy. Amounts of B(a)P declined 20 percent (almost exponentially from the initial 45 ..mu..g/kg wet weight) over the six-week experiment time. Mussels maintained out of water for three days starting on the day of transfer remained alive (simulating low tide behavior) but showed no significant change in B(a)P content. This suggests that mussel metabolism of B(a)P ceases on removal from water. Thus, it is apparent that short depuration periods (1-3 days), commonly used to eliminate bacterial contamination from edible shellfish before marketing, have little effect on the B(a)P tissue content in mussels. (ND)

The Use of Mussels in Estimating Benzo(a)Pyrene Contamination of the Marine Environment

In assessing the potential health hazards of a contaminated marine environment, particular attention should be directed to chemical carcinogens and mutagens. Such compounds may exert only a delayed effect, and remain undetected for a prolonged period, thus possibly accumulating to dangerous levels. The presence of carcinogenic polycyclic aromatic hydrocarbons (PAH) in plankton, seaweeds, filter feeding organisms, and bottom samples has been reported (reviews, 1-4). Unsolved remains the question of their geographical distribution and source, and the problem of a simple yet reliable detection method that would be applicable in a large-scale monitoring system. In this paper we explore the possible use of mussels (Mytilus edulis and Mytilus californianus) in estimating the distribution of benzo(a)pyrene (B(a)P) in coastal waters, and attempt to assess their suitability in an economic, simple, and relevant monitoring system. Mussels were chosen because of their widespread distribution, their sedentary habits, and their capacity to accumulate foreign compounds, including PAH (5). Benzo(a)-pyrene was selected because of its potency as a carcinogen, and its presence in a great variety of contaminating discharges that may enter shallow coastal waters (1, 3). Methods. The levels of benzo(a)pyrene in mussels and other samples were measured using a modification of a previously described procedure (6); 20-40 g (wet drained weight) of mussel tissue (generally 10-15 mussels) or 5-10 mg of creosoted wood were refluxed with ethanol and KOH, then water added and the PAH extracted into isooctane. Interfering materials were removed by chromatography on a column of Florisil, followed by dimethylsulfoxide extraction. Benzo(a)pyrene was separated from other PAH by thin-layer chromatography on cellulose-acetate. The B(a)P was quantitated fluorimetrically in hexadecane, using a baseline technique (7) to estimate the height of one of the peaks in the B(a)P emission spectrum.

Baseline levels of benzo(a)pyrene in southern California mussels

Abstract Marine mussels accumulate the carcinogen benzo(a)pyrene from contaminated environments. Baseline studies in California indicate that levels of the carcinogen in mussels are at or near zero, except in areas of human activity. This finding runs counter to previous suggestions that benzo(a)pyrene is widely distributed in marine organisms.

Micronucleus frequencies in urothelial cells of catheterized patients with chronic bladder inflammation

Epidemiological studies suggest an association between chronic inflammation and increased risk for cancer, although the mechanism underlying this relationship is unresolved. In the present study, we test the hypothesis that DNA damage is induced in the epithelium of tissues during such inflammation by products of activated inflammatory cells. Individuals on long-term indwelling urinary catheterization were used as a study population. These individuals have chronic bladder inflammation and, as a population, an increased risk for bladder cancer. Urine of 29 patients and 26 age-matched non-catheterized controls was collected and micronucleus (MN) frequencies were determined in exfoliated urothelial cells in the urinary sediments. The urine from the catheterized group had large numbers of white blood cells (mean count, 26.6 +/- 3.6 cells per high-power field), indicating the presence of a chronic bladder infection and an inflammatory reaction. In contrast, white blood cells were not present in urine from individuals in the control group. There was no significant difference in MN frequencies in the 2 groups (mean frequencies, controls: 0.098 +/- 0.030%; catheterized: 0.140 +/- 0.025%, p = 0.13). These data imply that chromosomal damage does not always occur during chronic inflammation. Although the reasons for this observation are yet to be determined, possible explanations include the pathophysiology of the inflammatory reaction and the influence of vitamins, non-steroidal anti-inflammatory drugs and the catheter itself in protection against inflammatory cell-mediated DNA damage.

Benzo(a)pyrene in the Marine Environment: Analytical Techniques and Results

The class of compounds known as polycyclic aromatic hydrocarbons (PAH) includes a number of potent carcinogens. Knowledge of the origin, distribution, and fate of PAH in the aquatic environment requires sensitive and reliable procedures for their measurement. Unfortunately, measurement of PAH in aquatic samples is frequently more difficult than analysis of these compounds in other samples such as air pollution particulates, cigarette smoke condensate, or coal tar or petroleum products. Levels of individual compounds are often low, and they may be intimately mixed with a complex organic matrix, such as the tissues of marine organisms or in the organic material of sediments.