Formation and persistence of DNA adducts in epidermal and dermal mouse skin exposed to benzo(a)pyrene in vivo.

Tritiated benzo(a)pyrene was applied topically to 35 old male Swiss mice that received 250 nMole (0.63 mCi) per mouse in 150 microliters acetone. At each time point of study, 1, 3 and 7 days, 10 animals were killed, the skin was removed and the susceptible epidermic cells were separated from resistant dermis. The initial level of the total BaP-DNA adduct after 1 day of test was 2 fold higher in epidermic cells; in addition, the concentration of the individual modified deoxyribonucleoside adducts was 4 fold greater in epidermis. However, the nature and the repartition of the modified nucleosides analyzed by high performance liquid chromatography were similar. They were 5 fold more in epidermic cells, except for the (+/-) SynBaP- diolepoxide - deoxyguanosine adduct which was 2 fold more in dermic cells. The major DNA adduct formed in both types of cells was the (+) antiBaP diolepoxide - deoxyguanosine = (+) anti BPDE-dG with 75% of total adduct in epidermic and 55% in dermal cells. The decreased amount of BaP bound to DNA of epidermic and dermic cells may be similar and 90% of (+) anti BPDE-dG was removed after a week of treatment; in addition, a minority that bound with 9OH-BaP was also shown to be persistent. Although the persistence of adduct was 7 fold more important in susceptible epidermal cells than in the resistant dermic population, the nature of adduct repartition and the similar type of excision suggest that other mechanisms are also involved in the biologically different response of epidermis versus dermis to the carcinogenic BaP when it is applied topically.

Generation of lymphokine-activated killer cells by adherent LGL phenotype cells and non-adherent T lymphocytes.

In this work we separated human blood lymphocytes (PBL) in two populations (A-LAK and NA-LAK cells) by the adherence plastic method. A maximum adherence of cells was obtained after 2 days of PBL incubation in LAK medium containing 500 U/ml rIL-2. The A-LAK cells had LGL phenotype but 40% of them had a macrophage phenotype marker and less than 20% weakly expressed a T-cell marker. This population, when reincubated in culture, produced an increasing titre of interferon. At the same time, a significant NK activity against K562 target cells was measured just after enrichment; these enriched adherent cells also developed an increased LAK activity against DAUDI cell lines, ninefold more at 6 days than when assayed just after enrichment. In contrast, 75% of the NA-LAK enriched cells expressed T-cell marker; these produced two- to threefold less interferon than A-LAK cells at all time-points. The NA-LAK lymphocytes enhanced principally LAK activity measured by 70% lysis against DAUDI target cells tested at 6 days of culture. Further studies are in progress to determine the nature of the effector cells that mediated LAK activity.

[Malt digestive system lymphomas and alpha heavy chain diseases. Histological and immunohistochemical study. Apropos of 3 cases]. / Lymphomes digestifs de type malt et maladies des chaînes lourdes alpha. Etude histologique et immunohistochimique. A propos de trois observations.

Malt lymphomas are lymphomas developed from mucosa associated lymphoid tissue and may involve many sites such as the gastrointestinal tract, salivary glands, thyroid gland lung, breast and female genital tract. Histologically, their diagnosis is based upon the existence of four elements: centrocyte-like cells that are responsible for lymphoepithelial lesions that are sometimes very difficult to demonstrate reactive or residual follicles and plasma cells. We study 2 cases of gastric Malt lymphoma and one of alpha heavy chain disease involving the small intestine and the stomach and we try to define the common features of Malt lymphoma, alpha chain disease and non-secretary IPSID, which all present the clinical tetralogy mentioned above.