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Biomedical subjects

M B Korolev

Publications and source records attributed to M B Korolev.

At least 19 recordsLinked to original sources
PubMed1990

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.

Amyotrophic Lateral Sclerosis↗
PubMed1989

Restricted growth of attenuated poliovirus strains in cultured cells of a human neuroblastoma.

Cultured cells of a human neuroblastoma, SK-N-MC, were found to be highly resistant to Sabin attenuated poliovirus types 1 and 2 strains; no appreciable cytopathic effect was observed, and the total harvest was generally in the order of 1 PFU per cell or less. On the other hand, related neurovirulent strains of these antigenic types produced a relatively good (2 orders of magnitude higher) yield in a markedly protracted infectious cycle. The limited growth of the attenuated virus in the neuroblastoma cells appeared to be confined to a minor cell subpopulation. Experiments with intratypic (type 1) poliovirus recombinants suggested that the major genetic determinants limiting reproduction of the attenuated polioviruses in the neuroblastoma cells are located in the 5' half of the viral RNA, although the 3' half also appears to contribute somewhat to this phenotype. The possibility that neuroblastoma cells may represent an in vitro model for studying poliovirus neurovirulence is briefly discussed.

Genes, Viral↗
PubMed1987

The structure of the capsid inner layer of reoviruses. Brief report.

It is shown that reovirus capsid inner layer consists of 132 capsomeres with a skewed icosahedral pattern of T = 13 (left). 780 structural units composing capsomeres are integrated into trimers. The boundary between capsomeres runs between the structural units forming trimers.

Capsid↗
PubMed1987

[Development of a Soviet diagnostic kit for determining class M immunoglobulins to the hepatitis A virus by immunoenzyme analysis (a test system for anti-HAV IgM)].

A new test system Diagn-A-Hep for the laboratory diagnosis of hepatitis A (HA) by means of the enzyme immunoassay has been developed at the Institute of Poliomyelitis and Viral Encephalitides (Moscow). The sensitivity and specificity of the newly developed test system have proved to be similar to those of the well-known commercial diagnostic system HAVAB manufactured by Abbott Laboratories (USA). Diagn-A-Hep permits the diagnosis of HA with 96-100% effectiveness both in patients with the acute form of the disease and in patients with its anicteric or inapparent forms. This system is simple and convenient, it may be employed in inadequately equipped laboratories or even under field conditions. The rules for the selection of immunobiological preparations to be included in the test system have been worked out.

Adsorption↗
PubMed1987

Persistence of the scrapie agent in glial cells from rat Gasserian ganglion.

Persistence of the scrapie agent in glial cell monolayers from rat Gasserian ganglion have been studied by electron microscopy, virologic and histologic methods. Under chosen experimental conditions the scrapie agent had been shown to persist in cells for over 2 years. The infected cells appeared to be infectious for BALB/c mice throughout. Persistence of the scrapie agent was associated with development of a marked proliferative effect with increasing mitotic index of the cells. Changes similar to those observed in the CNS in vivo were found by means of electron microscopy. The decreased number of oncovirus-containing cells seems to indicate the decreased proportion of such cells in the culture infected with scrapie agent.

Animals↗
PubMed1986

Peculiarities of tick-borne encephalitis virus reproduction in Haemaphysalis inermis ticks and their explants.

Virological, electron microscopic and immunomorphological investigation on the reproduction of tick-borne encephalitis (TBE) virus in Haemaphysalis inermis ticks and in tissue explants from nymphs during their metamorphosis revealed that the virus reproduced in the cells of different tissues and organs of ticks which were in different phases and stages of life cycle. During the eclipse phase of TBE virus persistence in ticks, when no virus could be demonstrated by infectivity assay, viral particles were detected by electron microscopy.

Animals↗
PubMed1984

[Characteristics of the filterable forms of Mycobacterium tuberculosis and their significance in pathology].

The results of the present investigation indicate that antituberculosis therapy for a period of 6 months leads to qualitative changes in M. tuberculosis population. This is manifested by the appearance of the filterable forms of M. tuberculosis in pathological material. At the same time these forms retain the initial pathogenicity of M. tuberculosis and induce not only tuberculous, but also nonspecific inflammation. Among the population of these filterable forms organisms carrying the genetic information of the species and capable of replication processes have been detected.

Animals↗
PubMed1983

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.

Animals↗
PubMed1983

[Isolation and study of the morphological properties and immunogenicity of filterable forms of Mycobacterium tuberculosis].

The experimental study made on 185 guinea pigs revealed that during the chemotherapy of destructive tuberculosis the typical bacterial forms of M. tuberculosis rapidly disappeared, but the cavities of destruction were retained and the presence of the filter-passing forms of M. tuberculosis, along with antigenemia and specific cell-mediated and humoral immunity could be detected. The use of repeated biological subculturing resulted in the reversion of the filter-passing forms of M. tuberculosis to their typical bacterial forms; simultaneously the increase of antigenemia (from subculture to subculture) and the enhancement of immune responsiveness occurred.

Animals↗
PubMed1979

Investigation of physicochemical properties of Bulgarian strain 258 of enterovirus type 71. Brief report.

In the present report some general physicochemical properties and RNA characteristics of strain 258 of enterovirus (EV) 71, isolated in 1975 from cases of poliomyelitis-like disease in Bulgaria (1), are described. It is concluded, that the features of the virus are consistent with the previous identification, based on biological studies, of this virus strain as a member of enterovirus subgroup of picornaviridae family.

Animals↗
PubMed1979

[Experience in examining infectious hepatitis patients by using a viral detection method].

Immune electron microscopy was shown to be an acceptable diagnostic method which allowed to detect hepatitis A virus particles in the stools of patients with infectious hepatitis even at the late stages of the disease. The examination of stools from 225 children (aged 2--17 years) hospitalized with diagnosed infectious hepatitis during the period of a seasonal rise in morbidity rate yielded positive findings at an average rate of 10.5%. This rate also depended on the severity of the disease and the patient's age. The results obtained indicated that patients with infectious hepatitis could shed the virus for a long time (about 2 weeks) after the onset of the disease. Patients with the atypical, or anicteric, form of the disease could be equally considered a source of virus shedding. The prolonged excretion of viral particles did not correlate with delayed IgM response. The particles identified as hepatitis A virus seemed to be antigenically very close, if not identical, to the virus circulating in some other countries (USA, Australia, West Germany).

Adolescent↗
PubMed1979

Chronic form of experimental rabies in mice.

The L-28 strain of street rabies virus isolated from the salivary gland of a red fox caused chronic infection in mice. After intracerebral (i.e.) infection with virus-containing fox salivary gland suspension, 13.9% of mice showed clinical signs of disease for 11--52 days. Clear-cut stages of irritation and paralysis were distinguished in the course of infection of mice. The diagnosis of chronic rabies in mice was confirmed by immunofluorescence and isolation of virus by i.c. inoculation of mice. Electron microscopic examination of the Ammon's horn of mice revealed a slow development of morphological changes connected with the formation of virus-specific structures. The gradual increase in the number and size of aggregates of viral ribonucleoprotein was followed by the appearance of membranous and tubular structures. Along with the latter, typical bullet-shaped particles of rabies virus were found in some neurons on the 43rd day of infection.

Animals↗