[Some features of measles virus morphogenesis in highly differentiated human astrocyte cultures]. / Nekotorye osobennosti morfogeneza virusa kori v kul'turakh vysoko- differentsirovannykh astrotsitov cheloveka.

Astrocyte cultures of adult human brain were used to study the morphogenesis of measles virus at different multiplicity of infection. High-dose (1 to 10 TCD50/ml) inoculation of the culture was found to give rise to an acute infection with cytolysis on days 10-12 postinfection and formation of extracellular mature virions. Low multiplicity of infection (0.01-0.1 TCD50/ml) caused the persistence of virus. During a persistent infection the virus in titers 1.7 to 2.4 lg TCD50/ml was detected as long as up to the 3rd passage. Ultrastructural studies of such cultures revealed some features which were not observed in an acute infection: (1) the diameter of intracytoplasmic RNP increased by 1.5 times vs. that in other cell cultures because of coarse thickening of the envelope; (2) numerous immature virions in which nucleocapsids were completely or partially absent; and (3) uncommonly low number of mature virions. Moreover, alterations in the spatial orientation of cytoskeleton components, such as intermediate and thin (actin) filaments were observed. A conclusion is made that astrocytes as a reservoir for measles virus accumulation serve as the source of immature envelope virus production, which may be one of the possible causes of sclerosing panencephalitis. The causes of disturbances in RNP transport from the site of assembly to cell membrane are discussed.

[Morphological characteristics of the course of HIV infection in laboratory animals]. / Morfologicheskaia kharakteristika techeniia VICh-infektsii u laboratornykh zhivotnykh.

The integrative form of infection was obtained in cotton rats intraperitoneally or retrobulbarly infected with the highly-productive strain Zmb HIV-1. Clinically, it appeared as reduced animal weight gain and high mortality rates in the disease terminal stage. The proviral DNA was detected by the polymerase chain reaction in the genomes of cerebral and splenic cells in most animals. A comprehensive study of the time course of morphological changes within 6 months showed impairments in some CNS cells, giving rise to glial nodules and neurone dystrophy. It should be noted that the most profound changes were observed when the virus had been intraperitoneally injected. It was found that some pathomorphological changes were similar to those seen in human neuro-AIDS. In the spleen, HIV-1 first stimulated an immune response, caused an increase in the extent of white bulb follicles and an active formation of germinative centers, then involution of lymphoid formations took place.

[Virus-induced dyslipidemias as possible risk factors in the development of somatic diseases]. / Virusindutsirovannye dislipidemii kak vozmozhnye faktory riska v razvitii somaticheskikh zabolevanii.

Experimental and clinical studies showed a number of virus infections to be accompanied by lipidemic disorders. Experimentally, dyslipidemias were found in tick-borne encephalitis (TBE) in mice, rotavirus infection in rabbits, and amyotrophic leukospongiosis in guinea pigs. The possibility of correcting the virus-induced lipidemic disorders with an antiviral drug, lincomycin, was demonstrated in TBE in mice. Dynamic study of the lipidemic status of patients with virus hepatitis A revealed marked dyslipidemia of the atherogenic type which was stable and persisted up to the time of clinical recovery. The data obtained supplement the current concepts concerning the pathogenesis of virus infections.

[Mechanism of accumulation of prion amyloid in the CNS in experimental amyotrophic leukospongiosis]. / K mekhanizmu nakopleniia prionovogo amiloida v TsNS pri éksperimental'nom amiotroficheskom leikospongioze.

The mechanism of accumulation of prion amyloid in guinea pig CNS in experimental slow virus disease--amyotrophic leuco-spongiosis (AL) was studied. The complex histochemical, immuno-cytochemical and ultrastructural studies revealed specific amyloid deposits in a few brain capillaries and in most of pia matter vessels. Taking into account the high AL agent titer in spleen throughout the disease period, conclusion was drawn of entering AL agent in CNS through blood-liquor barrier and blood-brain barrier. It was supposed that primary immune system damaging took place in AL pathogenesis.

[The formation of infectious scrapie-like structures in the persistence of the agent of amyotrophic leukospongiosis in a brain cell culture]. / Formirovanie infektsionnykh skrepipodobnykh struktur pri persistentsii agenta amiotroficheskogo leikospongioza v kul'ture kletok mozga.

Electron microscopic analysis of specimens from guinea-pig brain cell cultures infected with amyotrophic leucospongiosis agent (belonging to "unconventional" viruses) revealed accumulation in the culture fluid of abnormal filamentous structures similar to scrapie-associated fibrils (SAF) differing in morphology. Most of these SAF-like structures 10-15 nm in diameter contained helically wound protofilaments with a repeat at certain intervals (50-150 nm). When these structures were inoculated into guinea-pig brain astrocyte cultures they produced dystrophic-destructive changes in some (25%) astrocytes, and their intracerebral inoculation to guinea pigs produced an experimental disease. The abnormal SAF-like structures were reisolated from the brains of the inoculated animals which indicated the relationship between these structures and infectivity.

[The use of electron microscopy for diagnosing spongiform encephalopathies]. / Ispol'zovanie élektronnoi mikroskopii dlia diagnostiki spongioformnykh éntsefalopatii.

The authors suggest an unsophisticated approach to laboratory diagnosis of spongiform encephalopathies induced by unconventional prion viruses, consisting in electron microscopic detection of abnormal helical Scrapie-associated fibrils. These fibrils are detectable in human and animal brain tissue samples and in cell cultures.

[The biological properties of the HIV isolated from a virus carrier living in the Byelorussian SSR]. / Biologicheskie svoistva VICh, vydelennogo ot virusonositelia, prozhivaiushchego v BSSR.

Biological properties of an AIDS agent first isolated from a native citizen in the USSR are presented. The source of the virus was a young Byelorussian woman who in the near past had had sexual contacts with a citizen from one of the Central Africa countries. The isolate is thought to be of HIV-I type. It replicated perfectly in many continuous lymphocyte lines and had HIV-characteristic morphology. The protein spectrum of the isolate was gp120, gp41, p65/51, p55, p32, p24, p17. Reverse transcriptase activity was detected in the culture fluid of the virus-containing cell cultures. The isolate was designated HIV-IZ.

[The persistence of the causative agent of amyotrophic leukospongiosis and the astrocyte reaction in monolayer cultures of brain cells]. / Persistentsiia vozbuditelia amiotroficheskogo leikospongioza i reaktsiia astrotsitov v monosloinykh kul'turakh kletok mozga.

The amyotrophic leukospongiosis (AL) agent which is considered to be an unconventional virus was shown to replicate and amplify in non-neuronal monolayer brain cell cultures. The AL agent persistence was accompanied by complicated morphofunctional changes in astrocytes, some of them developing a specific cytodystrophic process. Phagocytosis in the infected astrocytes came to its end. The dose-dependent effect and selective sensitivity of these cells to the cytodestructive activity of AL was demonstrated. Astrocytes are regarded to be target cells serving as a reservoir for agent amplification.

[Electron microscopic study of Lassa virus]. / Elektronno-mikroskopicheskoe izuchenie virusa Lassa.

Ultrafiltration through hollow fibrous filters followed by purification in interrupted and linear urografin gradients yielded a Lassa virus suspension of high concentration. The use of gamma-irradiation for inactivation of the frozen virus suspension (-70 degrees C) caused no apparent structural changes of virions and made it possible to examine Lassa virus in electron microscope by negative staining. The observed virus particles in their morphology and sizes did not differ from previously described particles of other members of the Arenaviridae family. In ultrathin sections of Lassa virus-infected Vero cells, atypical virions were sometimes visible alongside with typical particles. Within one type of such particles no ribosome-like granules could be detected. Such "hollow" particles may possibly be defective virions. Another kind of atypical particles contained homogeneous electron-dense core and resembled mycoplasma. Of greatest interest are the particles with heterogeneous core in which "sandy" granules can be distinguished. The presence of greater amounts of uranophilic material than usually may be explained by getting into the virion in the process of its formation of a greater amount of genetic material than that present in typical virions.