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Pollution from 35 perfluorinated compounds (PFCs) in the water of the Tokyo Bay basin was examined. The water in the basin contained relatively high levels of perfluorononanoate (PFNA), perfluorooctanoate (PFOA), and perfluorooctane sulfonate (PFOS) compared to the other PFCs, which were present at concentrations of 20.1 ng/L, 6.7 ng/L, and 5.8 ng/L, respectively. In contrast, the concentrations of their precursors and degradation products were an order of magnitude lower. Sewage treatment plant (STP) effluent in the area also contained high levels of PFNA compared with the river water samples (Mann-Whitney U-test, p<0.0002). From a spatial aspect, increases in PFC pollution levels correlated with increased urbanization in the study area suggested that there are nonpoint source contributors to the PFC pollution in this area. Branched isomers of the PFCs were also quantified. Samples that contained high concentrations of perfluoroalkyl carboxylates (PFCA) showed lower proportions of its branched isomer. This indicates that the branched isomers are more prominent in the area with lower PFC pollution. This analysis was beneficial for estimating the individual contributions of different PFCA production processes. This survey provided new information on the sources, spatial distribution, and behavioral characteristics of PFC pollutants in this area.

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Proliferative activity of the anterior pituitary cells in 2, 8, 15, 22 and 60-day-old mice was investigated by the use of a recently developed labelling method whereby bromodeoxyuridine (BrDU) incorporated into DNA is detected immunohistochemically using a monoclonal antibody. The anterior pituitaries were examined 3 h after BrDU injection. The number of BrDU-labelled cells/mmz of the anterior pituitary was greatest at 8 days. Labelling occurred less frequently at l5 and 22 days and was the lowest at 60 days of age. In most cases, BrDU-labelled cells were distributed homogeneously throughout the anterior pituitary. Immunoreactive cells, however, were occasionally concentrated in the marginal layer of the adenohypophysis at 2 days. To know the extent of the proliferative rate of already dilferentiated cells, sections were doubly immunostained for BrDU and several pituitary hormones. The number of doubly immunostained cells was generally small except for GH. The proportion of BrDU-labelled GH cells to all labelled cells increased from 5% to 25% through 2-22 days.Cell proliferation in the anterior pituitary gland is generally low in normal adult animals (17, 23, 24). However, mitotic activity of the pituitary increases after removal of peripheral target organs. To know which cell types are involved in such cytological changes, the anterior pituitary has been investigated after castration (9, ll, l7, l9) or thyroidectomy (3).Under normal conditions, pituitary cells proliferate actively during growth. However, only a limited number of studies have been made of this process. Shirasawa and Yoshimura (22) have examined the mitotic activity in the anterior pituitary of developing rats. In their study, colchicine was used to quantitate dividing cells. However, interpretation of 1On leave from the Department of Morphological Sciences, Faculty of Medicine, University of Salamanca, Spain 2T0 whom correspondence should be addressed results obtained from experiments using colchicine is not simple (25). Radioautography using [3H]thymidine is a far more effective technique but is time-consuming. While the mouse pituitary has not been adequately investigated, its small size greatly facilitates quantitative studies of cell proliferation.Recently, labelling with bromodeoxyuridine (BrDU) has been introduced as a method for identifying DNA-replicating cells both in vitro (6, I8) and in vivo (26). We have applied this method to assess the rate and site of cell proliferation in the developing mouse pituitary. We paid special attention to the proliferation of GH cells because they are the predominant cell type in immature mice (20).

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