[Morphogenesis of tick-borne encephalitis virus in the brain of mice infected with its persistent strains].

The brain cells of adult albino rats underwent electron microscopic study after intracerebral infection with tickborne encephalitis virus (TBEV) strains isolated after long persistence in monkeys, Syrian hamsters, and a patient with chronic tick-borne encephalitis. The TBEV morphogenesis scheme was shown to be fundamentally similar for both high-virulent and long persistent TBEV strains. Data on the budding of newly forming particles on the degranulated membranes of the irregular endoplasmic network are presented. The morphogenesis and molecular mechanisms of TBEV reproduction call for further comprehensive studies.

[Prion diseases at the present stage and the investigations conducted at the M. P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences].

The review deals with the basic characteristics of prion diseases of man and animals. It details the studies of some little known aspects of the pathogenesis of prion diseases and their lifetime diagnosis, conducted at the M. P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences, in the past decades.

[Pathology of the brain in Creutzfeldt-Jakob disease]. / Patologiia golovnogo mozga pri bolezni Kreittsfel'dta-Iakoba.

The autopsy cases of Creitsfeldt-Jacob disease (a sporadic form) are reported which were diagnosed clinically and supported by the data of biopsy and autopsy of the brain (classic triad: death of neurons, astrogliosis and spongiform degeneration of the gray substance of the cortex of brain hemispheres, preferentially), followed by clinical morphologic comparisons. The focal character of the disease was observed on the early stages of the disease, while diffuse alterations were found on the late stages.

[In vivo diagnosis of Creutzfeldt-Jakob disease]. / Prizhiznennaia diagnostika bolezni Kreitzfel'dta-Iakoba.

The paper presents the data concerning usage of some original method of vital laboratory diagnostics of Creutzfeldt-Jacob disease that belongs to the group of prionic diseases. The method consisted in the inoculation of inoculative culture of rat Gasser ganglion's neurinoma by biologic materials investigated (serum and clot of blood) with the following passivation and investigation of the contaminated culture by means of both morphologic and electron microscopic methods. As an example of vital verificated case the wide pathomorphologic analysis of the biopsy sample of brain was presented. Besides, the efficiency of the investigation of cognitive evoked potentials (P300) together with EEG was also demonstrated as the method of objectification of the development of dementia in this disease.

[Lifetime diagnosis of prion transmissive encephalopathies]. / Prizhiznennaia diagnostika prionovykh transmissivnykh éntsefalopatii.

An original method for life-time diagnosis of Greutzfeldt-Jakob's disease, a neurodegenerative disease belonging to transmissive spongiform encephalopathies, is proposed. It consists in inoculation of the examined biological materials (blood serum and clot) into a continuous culture of the rat Gasser's node neurinoma, followed by passages and study of the inoculated culture by morphological methods and electron microscopy.

[The Gerstmann-Sträussler syndrome: new diagnostic possibilities]. / Sindroma Gerstmanna--Shtreusslera: novye vozmozhnosti diagnostiki.

On the basis of clinical picture of the disease, data of CT, MRT, psychological study, original laboratory investigation aimed at indication of changes in transposed neuroglia cells induced by the causal agent of subacute spongious transmissible encephalopathies, the diagnosis of patient K., 49 years old, was considered to be: syndrome of Gertsmann-Sträussler [correction of Herstmann Streussler]. Duration of the disease was 2 years. The case was sporadic. The history of the problem, modern views on etiology, pathogenesis of preventive measures are presented.

[The interrelationship of the causative agents of subacute transmissible spongiform encephalopathies]. / O vzaimosviazi vozbuditelei podostrykh transmissivnykh gubkoobraznykh éntsefalopatii.

Virological, histological, and electron microscopy methods were used to study the features of the infectious process in minks infected with scrapie agent as compared with that in minks infected with the agent of mink transmissive encephalopathy and in mice infected with scrapie. The results of the study showed the similarity in the clinical picture and the pattern of histological and ultramicroscopic lesions in minks infected with either of the agents. On the basis of the authors' own data and those from the literature, the relationship among the agents of the diseases comprising the group of subacute transmissive spongiform encephalopathies is discussed.

[The properties of the particles formed in the reproduction of an acute in vitro infection with the tick-borne encephalitis virus adapted to H. plumbeum ticks]. / Svoistva chastits, formiruiushchikhsia pri vosproizvedenii ostroi infektsii in vitro virusom kleshchevogo éntsefalita, adaptirovannym k kleshcham H. plumbeum.

The properties of virions produced in pig embryo kidney (PEK) cells inoculated with tick-borne encephalitis (TBE) virus strain EK-328 which had been passaged in white mice and its variant obtained by passages of TBE in H. plumbeum ticks (clone 718/574 H. pl.17) were found to be different. The clone 718/574 H. pl17 virus particles had no hemagglutinating or precipitating activities, greater sedimentation and density heterogeneity in sucrose density gradient centrifugation, and differences in movements to electrodes in electrophoresis and immune electrophoresis. In mixed infection in PEK cultures with EK-328 strain and clone 718/574 H. pl17, the infective dose-dependent interference was observed which affected the infectious virus titre and the size of cathode antigen precipitate.

[The CNS lesion in monkeys spinally infected with the vaccinal poliomyelitis virus]. / Porazhenie TsNS obez'ian pri spinal'nom zarazhenii vaktsinnym virusom poliomielita.

Specific features of the CNS lesions in monkeys inoculated with a vaccine poliovirus strain were studied in comparison with those developing after inoculation with virulent strains. The lesions in the lumbar cord and other regions of the brain and spinal cord after intraspinal inoculation of the vaccine virus are described at length. Certain signs reflecting the specific nature of the lesions were observed. The results of histopathological and immunofluorescent studies were shown to be important for differentiation of specific and nonspecific lesions.

Molecular hybridization with cloned fragments of tick-borne encephalitis (TBE) virus cDNA in acute and chronic TBE infection.

Recombinant plasmid DNA was used as a probe to detect tick-borne encephalitis (TBE) virus RNA during incubation period, acute disease and persistent infection of syrian hamsters. Within the first three weeks post-infection the results of direct virus isolation and RNA detection in the brain agreed by a rate of 100%, the virus titre ranging between 10(1.9) to 10(10.5) LD50/ml and viral RNA concentration at 1-1000 pg. At the same time TBE virus RNA was detected in the spleen when the virus titre was greater than or equal to 10(6.5) LD50/ml. By 8 months post infection (p.i.) viral RNA was found in the brain, liver, and spleen in the absence of infectious TBE virus. No viral RNA was present in the thymus. In addition, electron microscopic findings in hamster brain confirmed the hypothesis that TBE virus persistence was accompanied by formation of virus-specific structures but impaired virion maturation.

Alterations of arginase activity in scrapie-infected mice and in amyotrophic lateral sclerosis.

We followed the dynamics of arginase activity, the ultrastructural changes, and accumulation of the scrapie agent in the CNS of scrapie-infected mice. The arginase activity has been shown to increase 5-fold within the first 3-4 months of the incubation period followed by subsequent fall at its end. The peak of increased arginase activity coincided with appearance of multilayer membranes, whereas the decrease of this activity was associated with the greatest development of status spongiosus, synaptic degeneration, accumulation of five-layer membranes as well as with maximal accumulation of the scrapie agent in the CNS. Examination of 100 patients with different forms of amyotrophic lateral sclerosis (ALS) revealed a 2-8-fold increase of arginase levels in the cerebrospinal fluid (CSF) as compared with the background levels in the comparative groups of control patients. Similar enzyme alterations in scrapie--and in ALS--are discussed in terms of possible resemblance of their pathogenesis.

[Cytomorphologic study of a line of hybrid somatic cells persistently infected with the scrapie agent]. / Tsitomorfologicheskoe issledovanie linii gibridnykh somaticheskikh kletok, persistentno infitsirovannykh agentom skrepi.

Virological, cytological and electron microscopic methods were used to study the peculiarities of the scrapie agent persistence in the tissue culture of the mouse and human hybrid cells. A long-term persistence of the scrapie agents in the cells (658 days) has been obtained. The fact of persistence is confirmed by the results of biotest and electron microscopic studies of the mouse CNS. The agent persistence promotes a decrease in the mitotic activity of the infected cells and development of the ultramicroscopic changes in cells similar to the picture of the specific changes in the CNS of mice inoculated by scrapie agent.

Identification of continuous green monkey spleen cell line 455.

Green monkey spleen continuous cell line 455 has been identified by karyologic analysis, by isoenzyme characteristics and electron microscopy. It has been shown that the line 455 consists of green monkey cells; it is not contaminated by other cells from the green monkey, or by other animal or human cells.

[Pathogenesis of persistent and chronic forms of tick-borne encephalitis (experimental study)]. / Patogenez persistentnoi i khronicheskoi form kleshchevogo éntsefalita (éksperimental'noe issledovanie).

A long-term experiment was conducted to study various aspects of the pathogenesis of persistent and chronic tick-borne encephalitis (TBE). Virological, serological, pathomorphological, electron microscopic and immunofluorescent techniques have been utilized in this study. Persistent TBE infection of Syrian hamsters examined over the period from 40 days to 2 years was characterized by the presence of virus-specific antigens in the organs and of specific antibodies in the blood serum. The persisting TBE virus was found to be predominantly localized in the central nervous system and spleen. Nerve cells underwent ultrastructural changes which were characteristic of flavivirus infection and related to the morphogenesis of viral particles. The authors have developed an experimental model of a primary progressive form of TBE with early and late manifestations of clinical symptoms of the disease.

Effect of hyperbaric oxygenation on experimental scrapie in mice.

The effect of hyperbaric oxygenation upon experimental infection of BALB/c mice with the scrapie agent was investigated by virological methods, histology and electron microscopy. A multiple exposure of scrapie-infected mice to hyberbaric oxygenation during the incubational period led to a certain aggravation of infection as evidenced by a greater accumulation of the agent in the central nervous system (CNS) and spleen, as well as by more pronounced ultramicroscopic changes in CNS. A single exposure to hypoxia failed to alter any manifestations of infection.

Comparative study of infectious and formaldehyde-inactivated tick-borne encephalitis virus particles.

The structure and properties of infectious and formaldehyde-treated particles of tick-borne encephalitis virus, concentrated and purified by chromatography on macroporous glass, were studied. In addition to complete virions, such preparations contain some incomplete forms that differ in density, morphology and protein composition (incomplete forms do not contain nucleocapsid protein). The physico-chemical analysis of complete virions showed that formaldehyde treatment causes a) the formation of glycoprotein dimers and b) a portion of nucleocapsid protein to become tightly cross-linked with viral RNA. Formaldehyde treatment of incomplete forms resulted only in the formation of a small amount of glycoprotein dimers. Incomplete forms and glycoprotein extracted from inactivated preparations had protective and antigenic activity.

Study of early stages of the pathogenesis of scrapie in experimentally infected mice.

Virological, histological, and electron microscopic methods were used to study the early manifestations of infection in brains and spleens of mice experimentally infected with the scrapie agent. A statistically significant increase in the spleen weight was demonstrated during the incubation period; this occurred only after intracerebral (i.c.) inoculation of the scrapie-containing brain suspensions and subcutaneous (s.c.) inoculation of the scrapie-containing spleen suspensions. No differences were observed between the scrapie agents replicating in the brain or spleen. In the brain at early stages of the incubation period, ultrastructural changes were observed in pre- and post-synaptic areas. The importance of these findings for understanding of the pathogenesis of subacute transmissible spongiform encephalopathy (STSE) is discussed.

[Spontaneous cytomegalovirus infection of kidney cell cultures of green monkeys]. / Izuchenie spontannoi tsitomegalovirusnoi infektsii kul'tur kletok pochek zelenykh martyshek.

In subcultivation of 104 batches of primary kidney cell cultures from clinically normal green monkeys 66 batches (47%) showed cytopathic changes indicating spontaneous virus contamination of the cultures. Sixty-six strains were isolated and the properties of 23 cytopathic strains were studied. Electron microscopic examinations of 6 virus isolates identified them as members of the herpesvirus group. Serological examinations of 335 clinically normal green monkeys demonstrated antibodies to one of our virus isolates (No. 8532) in 192 (57.3%) animals. Virus strain 8532 was neutralized by antiserum to green monkey cytomegalovirus M-1. The isolates obtained in the present study exhibit the properties previously unknown for green monkey cytomegalovirus such as the capacity for replication in rabbit, sheep, cow, and piglet cell cultures.

[Isolation of adeno-associated virus type 4 from a culture of green monkey kidney cells]. / Vydelenie adenoassotsiirovannogo virusa tipa 4 iz kul'tury kletok pochek zelenykh martyshek.

In the process of biological control of uninfected green monkey kidney (GMK) cell cultures a thermostable hemagglutinating agent designated No. 5056 was isolated alongside with adenovirus-SV. By its antigenic properties the 5056 strain was identified as adeno-associated virus type 4 (AAV-4). In control of 574 specimens of GMK culture batches, 40 AAV-4 strains were isolated in the presence of a helper adenovirus. Some biological properties of the isolates and their resistance to certain physical and chemical treatments were studied. Two isolates of the satellite virus were examined in the electron microscope. A correlation between the rate of AAV-4 isolation from GMK cultures and the presence of complement-fixing antibody to AAV-4 in monkey sera was observed.