Impairment of the blood-nerve and blood-brain barriers in apolipoprotein e knockout mice.

Apolipoprotein E (apoE) is well characterized as a plasma lipoprotein involved in lipid and cholesterol metabolism. Recent studies implicating apoE in Alzheimer's disease and successful recovery from neurological injury have stimulated much interest in the functions of apoE within the brain. To explore the functions of apoE within the nervous system, we examined apoE knockout (KO) mice.

[A method of concentrating viruses in environmental water sources].

The authors propose an effective and simple method for the collection and concentration of enteroviruses from environmental water bodies, which is based on adsorption properties of macroporous glass (MPG). MPG enveloped in water-permeable coating permits concentration directly in the water. Poliomyelitis viruses were 100-1000-fold concentrated in laboratory trials.

Electropherotypes and serotypes of human rotavirus in Estonia in 1989-1992.

The electropherotypes and serotypes of human rotaviruses circulating in Tallinn (Estonia) in 1989-1992 have been studied. Rotaviruses were found in 372 (25.8%) of 1,442 faecal specimens of pediatric patients with acute diarrhea.

Inactivation of simian rotavirus SA 11 by hydrogen peroxide.

The kinetics and extent of the simian rotavirus SA 11 (RV) inactivation by low concentrations of hydrogen peroxide (HP) were determined. The curves illustrating the kinetics of crude virus inactivation have "tailing off". The inactivation of the purified virus runs according to the first-order kinetics.

Analysis of rotaviral gastroenteritis in Tbilisi.

Electrophoretypes of 107 rotaviral isolates collected in Tbilisi for 18 months revealed seven patterns from which 4 were "long" and 3 "short". The "long" electrophoretypes represented 74.8% of total number of the isolates analysed.

Using different sorbents for the concentration of enteroviruses.

Comparative investigations were carried out to evaluate the efficiency of concentration (EC) of enteroviruses (poliovirus type 1 and simian rotavirus SA-11) using macroporous glass (brands MPG-1000 VGKh, USSR, and SO1, Czechoslovakia) and membrane filters (MF): (nitrocellulose PNTs 0.45, USSR, Millipore HAWP 0.45, USA, Synpor 0.

[Isolation of immunoglobulins from the egg yolk of hens immunized with intestinal viruses].

Antibodies from the yolk of eggs of chicken immunized with enteric viruses (simian rotavirus SA 11, poliomyelitis virus type 2, and Coxsackie B2) were obtained. The time course of the emergence and amplification of antibody in the yolk was followed for several months by neutralization tests and enzyme immunoassay. The long-term persistence of a high antibody level in the yolk, the simplicity of generation of large amounts of chromatographically pure preparations, as well as specificity of chicken immunoglobulins open ways for their employment in different test systems for the detection and identification of enteric viruses.

[Discovery and quantitative determination of intestinal viruses by the detection of viral antigens in infected cells using an immunoperoxidase method].

The use of immunoperoxidase method for detection of virus antigens in a fixed infected cell monolayer on microplates (cellular immunoperoxidase method, CIPM) for poliomyelitis and hepatitis A virus as well as for human and simian SA II rotaviruses is described, as well as the method of quantitation of rotaviruses by counting of virus multiplication foci. The CIPM combines the advantages of the methods based on the infectivity determinations and of immunochemical methods, and may be used both for diagnosis and for detection and quantitation of enteric viruses.

[Study of enteroviruses in different environments using guanidine-dependent variants].

Guanidine-dependent variants of enteroviruses were used as indicators for the study of the effectiveness of environmental object purification processes. The dependence of virus replication on guanidine provides complete safety of the virus for man and selective virus isolation from the objects under study. The use of the indicator virus allows to perform quantitation studies.

Demonstration of antigenic differences between strains of poliovirus type 1 by agar diffusion precipitation reaction.

Antigenic differences between type 1 poliovirus strains circulating in nature were investigated by agar diffusion precipitation reaction. Three strain-specific sera were absorbed with antigens prepared from 8 strains (Sabin's vaccine strain LSc2ab and 7 strains isolated from poliomyelitis patients or healthy persons). The results suggested the presence of at least 5 antigenic determinants in the poliovirus type 1 strains studied.

[Reproduction of murine encephalomyocarditis virus in enucleated Krebs 2 ascitic carcinoma cells].

Enucleated cells of ascites carcinoma Krebs 2 (cytoplasts) were prepared. The cells were centrifugated for this purpose in a discontinuous Ficoll density gradient containing cytochalasine B. The cytoplasts formed turbid bands in Phycol solution at the density of 1.

The effect of inhibitors of cellular RNA synthesis on stimulation of mouse encephalomyocarditis virus reproduction by poliovirus in HeLa and MIO cells.

Inoculation of HeLa and MIO cells with a guanidine-dependent mutant of poliovirus (gd-polio) in the absence of guanidine resulted in stimulation of mouse encephalomyocarditis (EMC) virus reproduction. No stimulation was found to occur in the presence of actinomycin D, on pre-treatment of the cells with cordycepin, or on their UV irradiation or enucleation. In contrast to HeLa cells, the enhancement of EMC virus reproduction by gd-polio in MIO cells required no current synthesis of cellular RNAs: it occurred in the presence of actinomycin D, upon UV irradiation of the cells or their enucleation.

[Stimulation of mouse encephalomyocarditis virus reproduction by non-multiplying poliomyelitis virus in several transplantable tissue culture lines].

Reproduction of mouse encephalomyocarditis virus (EMC) was studied in 5 continuous primate cell lines: HeLa, Fl, Detroit-6, P/7, and MIO inoculated with guanidine-dependent variant of poliomyelitis virus in the absence of guanidine. Poliomyelitis virus stimulated EMC virus reproduction in all cell lines under study. This stimulation effect was studied at length in HeLa and MIO cells.