[Standardization of carbon fluoride aerosols in the air of the working area]. / Materialy k normirovaniiu aérozolia ftorouglerodnykh volokon v vozdukhe rabochei zony.

Hygienic studies were conducted by means of pilot industrial plant for production of carbon tetrafluoride fibers (CTF). The studies proved that the main hazards of the production are CTF dust and hydrogen fluoride. Average shift concentrations of CTF dust in tne air of workplace equal 0.6-1.5 mg/cu m which 2 times higher than the MAC for HF at all technologic sites except for reactor compartment. The workers servicing the plant demonstrate higher urinary fluor excretion mostly due to HF intake. Experimental studies showed that CTF have low cytotoxicity and fibrogenic activity, these chemicals are assigned to IV jeopardy class (mild hazards). If applied on skin, CTF are absorbed and induce slight local irritation. The MAC for CTF in the air of workplace is set at 6 mg/cu m.

On the defensive action of glutamate against the cytotoxicity and fibrogenicity of quartz dust.

The cytotoxic action of quartz (DQ12) particles on cultures of rat peritoneal macrophages, as estimated by the inhibition of the TTC-reductase activity, is considerably reduced by preincubation with glutamic acid and by adding sodium glutamate (15 mg/ml) to the drinking water of the rats donating the macrophages. This increase in macrophage resistance under the influence of glutamate is the most probable cause of the delay in the development of silicotic fibrosis shown in several experiments on rats intratracheally injected with quartz and then treated by prolonged administration of glutamate. This effect is probably connected with the influence of glutamate on the stability of the macrophage membranes, which can in its turn be explained by different mechanisms, including the influence on the synthesis and phosphorylation of adenosine nucleotides. Such an influence was shown in rats receiving glutamate by the change of the ATP/ADP ratio in macrophages, but not in erythrocytes. The resistance of rat erythrocytes to the haemolytic action of quartz is also not influenced by the action of glutamate neither in vitro nor in vivo. Such differences in the influences of glutamate on two types of cells, equally susceptible to quartz cytotoxicity but considerably differing in the character of energy metabolism, is an indirect proof of the role of the latter in the realisation of the anticytotoxic, and thereby antifibrogenic, effect of glutamate.