[The role of fibrin clot degradation products in the regulation of vital functions of PC-12 cells].

The products of the fibrin clot hydrolysis performed by PC-12 cells modulated dose-dependently the rate of cell proliferation and favored their survival when seeded in suboptimal density. Co-incubation of PC-12 cells with fibrin degradation products enhanced cell adhesion to tissue culture plastic, as well as the number of nicotinic acetylcholine receptor alpha3 and alpha5 subunits expressed. It was demonstrated that, in fact, such a heterogeneous and comprehensive influence was a sum of effects exerted by different fibrin fragments.

[PC-12 cells hydrolyze the fibrin clot by producing both plasminogen and its tissue activator].

It has been shown that rat pheochromocytoma PC-12 cells degraded fibrin clots in vitro. SDS-PAGE performed in the gels of different density and Western blotting using monoclonal antibodies against DD- and D-fibrin fragments demonstrated that both high and low molecular weight degradation products similar to those of fibrin hydrolysis by plasmin had been formed. Enzyme electrophoresis, chromogenic assay and enzyme-linked immunosorbent assay using tPA-specific antibodies demonstrated that PC-12 cells constitutively secreted both plasminogen and tPA.

[Complement-binding and immuno-modulating properties of polyreactive immunoglobulins].

New data concerning biological properties of polyreactive immunoglobulins (PRIG) were obtained as a result of treatment of mouse serum immunoglobulins by 4 M KSCN and are presented in the paper. In particular, the capacity of PRIG to bind C1q, the subunit of the first component of complement was studied. It was shown that PRIG's binding capacity to C1q is similar to that of intact immunoglobulins.

[Regulation of fibroblast adhesion by polyreactive antibodies].

The effect of polyreactive antibodies on fibroblast adhesion was studied. Dose-dependent decrease of adhesion was found at the stage of adhesive complex formation. A possible mechanism of this effect was determined as a steric influence on integrin agregation and clastering.

[Transformation of serum immunoglobulins to polyreactive antibodies].

In order to elucidate the mechanism of induction of serum immunoglobulins polyreactive properties by chaotropic ions, gel-chromatography of immunoglobulins in the medium containing 3.3 M KSCN, has been done. It was found that the transformation of serum immunoglobulins to polyreactive antibodies, which could react with different serological unrelated antigens, was not followed by dissociation of any hypothetical blocking factors.

[Chromatographic analysis and immunobiologic properties of tuberculins].

Immunobiologic activities of tuberculin preparations and their components have been comparatively studied using gel filtration and high-performance liquid chromatography (HPLC) techniques. It is shown that high-molecular weight fraction of protein-purified derivate tuberculin (PPD) had higher activity as compared to nonfractionated preparation in skin tests on guinea pigs sensitized with Mycobacterium bovis BCG as well as in enzyme-linked immunosorbent assay with affinity purified rabbit antibodies against PPD. Using the preparative HPLC-technique we failed to isolate a component of PPD having greater tuberculin test potency than nonfractionated preparation.

[Seasonal changes in the count of mites of the family Pyroglyphidae in houses in the city of Cheboksary].

The results of human dwelling houses surveying for the presence of home dust mites and study of seasonal changes of their quantity in the town of Cheboksary are given. It has been found that the old wooden houses are inhabited by mites, in modern blocks of flats they are met rather seldom. The quantity of alive mites is maximum in September-October.