A further experimental study of the antisilicotic effect of glutamate.

Two groups of rats were exposed to quartz dust for six months and in addition one group was given drinking water containing 1.5% sodium glutamate while the second received only water. In the rats receiving glutamate we observed (a) evidence for a considerably reduced cytotoxic effect of the quartz on cells obtained by bronchopulmonary lavage, (b) a reduction in dust retention in the lungs, especially in the tracheobronchial lymph nodes, (c) a considerable reduction in the weight gain in the lungs and in their hydroxyproline and lipid contents, and (d) the inhibition of the formation of silicotic nodules. Polarographic studies of the oxygen consumption of peritoneal macrophages from rats receiving glutamate showed that glutamate prevents the adverse effects of quartz on mitochondrial oxidative processes.

[Change in the content of a series of components of rat lung connective tissue in the process of aging]. / Izmenenie soderzhaniia riada komponentov soedinitel'noi tkani legkikh krys v protsesse stareniia.

Content of soluble and insoluble collagen, glycosamine glycans, glycoproteins, lipids and nucleic acids was studied in rat lungs during postnatal ontogenesis (up to 32 months). Three age groups of animals, corresponding to juvenile, mature and old age, were used. Intensive collagenoformation and high content of soluble collagen fraction were found in animals of juvenile age. Mature age was characterized by static equilibrium between soluble and insoluble collagen fractions as well as by stabilization in concentration of RNA, hexuronic acids, hexoses, tyrosine, sialic acids and total lipids. Decrease of DNA concentration with simultaneous increase in phospholipid content preceded in ageing the alteration in collagen composition - elevation in insoluble and loss of soluble its fractions. At the ageing period content of glycosamines was relatively decreased but concentration of other substances varied slightly.

[Interrelationships between lipids and scleroproteins in silicosis caused by crystalline and condensed modifications of silicon]. / Vzaimootnosheniia mezhdu lipidami i skleroproteinami pri silikoze, vyzvannom kristallicheskoi i kondensirovannoi modifikatsiiami kremnezema.

Accumulation of lipids, including phospholipids, in lungs was accompanied by a proliferative-cellular reaction. The proliferation of cells was caused by accumulation of lipids. One of possible mechanisms of interrelation between lipids and collagen synthesis was as follows: in silicosis degradation of macrophages was accompanied by secretion into the medium of phospholipids, which inhibited free radical oxidation; in this case the decreased formation of cytotoxic products caused the cell proliferation, including fibroblasts, which produced collagen. The importance of lipids in collagen formation was corroborated: by accumulation of lipids, which preceded the hydroxyproline increase (scleroproteins, collagen), by development of the proliferative-cellular reaction together with the higher phospholipid-hydroxyproline level as compared with control, by formation of earlier sclerosis of silicotic nodes in "condensed" silicosis with the simultaneous increase in absolute content of phospholipids and total lipids. This role of lipids was also supported by the observed correlation between the absolute contents of scleroproteins and lipids within all steps of "quartz" silicosis development.

[Content of hexuronic acids, hexoses and tyrosine in the lung tissue in experimental pneumoconiosis]. / Soderzhanie geksuronovykh kislot, geksoz i tirozina v legochnoi tkani pri eksperimental'nykh pnevmokoniozakh

Content of hydroxyproline, thyrosine, hexuronic acids, hexoses and dry weight of lungs were studied in animals with pneumoconiosis, caused by various agents: two types of silicosis, induced by crystalline and condensed modifications of silica, and anthracosis, caused by anthracite. The data obtained showed that in all the types of pneumoconiosis dry weight of defatted lungs was increased with simultaneous increase of hydroxyproline content in the tissue. The more pronounced alterations were observed in silicosis. In all the types of pneumoconiosis within the experimental period content of hexuronic acids was higher in impaired animals as compared with control ones; the increase in content of hexuronic acids preceded the accumulation of hydroxyproline. Content of hexoses and thyrosine was distinctly increased within 2 days, which apparently correlated with the processes of exudation. Then it was decreased and at the later steps of the impairment amount of hexoses and thyrosine was shown to increase with simultaneous accumulation of hydroxyproline. Dynamics of accumulation of non-collagen components of connective tissue in lungs depended upon the type of a dust to which the animals were exposed.