Psoralen-photosensitized damage of rat peritoneal exudate cells.

Psoralen-sensitized photodamage (PUVA) of rat peritoneal exudate cells was investigated. Quartz-activated luminol-dependent chemiluminescence (ChL) was registered and the amount of trypan-positive cells was determined. Irradiation of peritoneal exudate cells in the presence of psoralen resulted in a dose-dependent monotonous inhibition of ChL. The reciprocity law of irradiation intensity and duration of irradiation was not valid for the observed inhibition of ChL: the inhibition increased with higher intensity. When psoralen previously photooxidized in ethanol (POP) was added to peritoneal exudate cell suspension, a double-phase response depending on psoralen irradiation dose was obtained: ChL activation was observed at low doses of UVA, ChL inhibition at high doses. Chemiluminescence inhibition correlated well with the increase in the number of trypan-positive cells. It may be supposed that the observed effects of PUVA or POP treatment are caused by cell cytoplasmic membrane damage.

[Data for the substantiation of the maximum permissible exposure level of armos fiber dust in the air of the work area]. / Materialy k obosnovaniiu PDK pyli volokna armos v vozdukhe rabochei zony.

The 'Armos' fibre dusts are characterized by low cytotoxicity, absence of fibrogenicity, display non-toxic properties in single exposures with no skin-irritating and sensibilizing effects. In repeated introduction into the stomach, the trachea, and if inhaled, these dusts displayed weak toxic properties. Dust concentrations at 10 mg/m3 are in proximity to the threshold one. The MAC for 'Armos' dusts in working zone areas was recommended at 5 mg/m3 (4th class of hazardness).