[Morphological characteristics of the brain lesions in mice infected with a homogenate of L cells latently infected with the scrapie agent]. / Morfologicheskie osobennosti porazhenii mozga myshei, zarazhennykh gomogenatom kletok L, latentno infitsirovannykh agentom skrepi.

Degeneration of neurons of the Ammon horn lower branch both in the early and terminal stages of the disease of mice infected with the homogenate of L cells latently infected with the scrapie agent (the L-S system) was frequently detected alongside with brain lesions typical of slow infections (vacuolation). Examinations of chromosomes in metaphase plates of L-S cells carried out by several methods including the TAC system for texture analysis of the image (Leutz, BRD) revealed three marker chromosomes new for continuous L cells, the appearance of true chromatid translocations as well as significant changes in chromosome numbers. Besides, ultrastructural features of L-S cells at later stages of cultivation were revealed. It is assumed that the active effect of the scrapie agent on L cells infected with it resulted in the emergency of a new antigen capable to induce selective affection of the neurons of the Ammon horn lower branch in susceptible mice.

[Infectious activity of cell fractions isolated from the brain of mice with scrapie]. / Infektsionnaia aktivnost' fraktsii kletok, vydelennykh iz mozga myshei, bol'nykh skrepi.

The agent of scrapie was found to induce clinically similar diseases in BALB/c and NIH mice but differing in the duration of the incubation period (155-180 days and 110-140 days, respectively) and pathomorphological manifestations. Differentiated examinations of a brain cell pool from mice with scrapie revealed more infectious activity not neutralized with nucleases and pronasa in membrane-free cell fractions than in fractions of slowly sedimenting membranes.

[Finding of the herpes simplex virus by electron microscopic study of the biopsy from a cervical cancer patient]. / Obnaruzhenie virusa obychnogo gerpesa pri élektronno-mikroskopicheskom issledovanii bioptata bol'noi rakom sheiki matki.

The question of a possible etiological role of the family of herpes viruses in generation of human malignancies is discussed. The detection of herpes simplex virus in human tumor by electron microscopic examination of a biopsy sample from a cervical carcinoma patient is another proof of herpes virus association with human malignant neoplasias.

[Latent infection of continuous L23 cells caused by the agent of scrapie]. / Latentnaia infektsiia perevivaemykh kletok L23, vyzvannaia agentom skrepi.

Two models of latent infection of continuous L23 cells caused by scrapie agent were developed using the method of cell cloning as well as DEAE-dextran and lidase preparations. The infectious activity was found only in cell homogenate L-C and L-506 (cells of clone L23 latently infected with the Compton and C-506 strains of the scrapie agent). A direct relationship between the infectious activity of the cell homogenate and the intensity of brain lesions revealed by morphological examinations of brain sections from infected mice was observed. The cytoplasm of L-C and L-506 cells became strongly vacuolated, piknosis of the nuclei and delay in the cell growth rate were noted. Cytogenetic studies established changes in the model class of the experimental cultures as well as the appearance of rearranged chromosomes.

[Biological variants of a population of strains of the rabies street virus]. / Izuchenie biologicheskikh variantov populiatsii riada shtammov ulichnogo virusa beshenstva.

Experiments in mice weighing 6-7 g showed that a population of wild street rabies virus strains could contain from 1 to 3 biologic variants determining the clinical characteristics, duration of the incubation period and of the disease, and virus titres in the brain. Fox strains L-1 and L-2 produced only paralytic rabies, the BE strain isolated from a badger induced paralytic and chronic disease, and the population of the Yak strain isolated from a boy bitten by a fox and timely given a complete course of postexposure treatment contained 3 biologic variants: (1) VAR produced acute paralytic rabies throughout 59 passages, (2) VVR induced a disease of the type of "violent" rabies throughout 20 passages, and (3) VCR provoked chronic rabies in 27 passages.

[Course of influenza in cyclophosphane suppression of cellular and humeral immunity]. / Techenie grippoznoi infektsii v usloviiakh podavleniia kletochnogo i gumoral'nogo immuniteta tsiklofosfanom.

Under conditions of immunosuppression of B- and T-cell functions with cyclophosphane, experimental influenza in mice infected with A/Aichi/2/68 (H3N2) runs early in the infection a much milder course than in mice given no such treatment. The mortality among immunosuppressed mice was 5 times as low as in the controls; the virus could be isolated from the lung tissue earlier and in higher titres; cyclophosphane inhibited the synthesis of antibodies and nonspecific thermolabile and thermostable tissue and serum inhibitors. Hepatization of the lungs in immunosuppressed animals was considerably less marked. The effect of cyclophosphane appeared to depend on its antiinflammatory properties.

[Immune response during the course of chronic experimental rabies]. / Immunnyi otvet pri éksperimental'noi khronicheskoi rabicheskoi infektsii.

The immune response was studied in the time course in comparison with virus titers in the brain in chronic course of the disease in random-bred and BALB/c mice infected intracerebrally with street rabies virus, the Yak strain. The virus-neutralizing antibodies were first found in the blood by the end of the incubation period and in the brain tissue at 7-8 days of the disease. Then their titers increased as the disease progressed reaching maximum (in the blood 1:97,313, in the brain 1:63,090) by 42-55 days. From the moment of virus-neutralizing antibody detection in the brain tissue virus titres decreased progressively with the period of the disease and increasing antibody concentrations in the brain tissue. By 42-55 days of the disease virus titres did not exceed 1.0 lg LD50/0.03 ml. Similar virus titer--antibody concentration in brain tissue dependence was observed in experiments in rats and rabbits. Very high antibody titers in the blood and brain tissue had no effect on the progredient course of the disease and fatal outcome. The study allowed the diagnostic criteria of chronic infection to be determined as well as its differences from the acute and abortive forms of rabies.

[2 biological variants of the rabies virus obtained from 1 strain]. / Poluchenie dvukh biologicheskikh variantov virusa beshenstva iz odnogo shtamma.

Two variants of rabies virus were obtained in experimental mice from one wild strain. They differed in the duration of the incubation and clinical periods and in virus titres. One virus variant produced an acute disease and the other acute and chronic forms of the disease. These properties persisted throughout 21 and 12 successive passages, respectively.

[Isolation of herpes simplex virus in chronic meningoencephalitis]. / Vydelenie virusa prostogo gerpesa pri khronicheskom meningoéntsefalite.

Virological examination of a patient suffering from chronic meningoencephalitis was carried out using serological and morphological methods. Strains of herpes simplex virus were isolated from the saliva, cerebrospinal fluid, and blood of the patient simultaneously in white mice and tissue culture. A rise in antibody titers to the isolate, its high neuropathogenicity in animal inoculation experiments, and the results of pathomorphological studies confirm the herpetic nature of the neuroinfection in this patient. Serological identification and investigation of biological properties of the virus showed it to belong to the 2nd antigenic type of herpes simplex virus.

[Pathomorphology of abortive rabies]. / Patomorfologiia abortivnogo beshenstva.

White random-bred mice inoculated intraperitoneally with street rabies virus were found to have numerous Babes-Negri bodies in cerebral neurons very frequently up to 5 days of the disease. On the 7-11th days of the disease the inclusions were found in some neurons in 11 of 17 mice examined. Among 24 mice with abortive rabies (recovering completely or surviving with residual symptoms such as pareses or paralysis) examined on the 20-240th days after the onset occasional Babes-Negri bodies were found either in the brain or in the spinal cord in 6 animals only. The central nervous system of these animals showed weak degenerative and inflammatory lesions; the animals had high antibody titers but yielded no virus. It is concluded that in some cases abortive infection becomes a latent one.

[Persistence of attenuated poliomyelitis virus in the organs of vaccinated animals]. / O persistentsii attenirovannogo virusa poliomielita v organakh vaktsinirovannykh zhivotnykh.

Experiments in cotton rats weighing 60-80 g orally vaccinated with gradually decreasing doses of live poliovaccine type II causing immunological changes of varying intensity demonstrated the attenuated poliomyelitis virus to penetrate the CNS, lungs, and spleen quite regularly. The virus could be isolated from the cytoplasmic extracts of these organs for up to 45 days, from the spleen for 60 days. Penetration of the virus into the CNS did not result in the development of disease. The long-term persistence of the virus in the organs was accompanied by the development of inflammatory-degenerative changes in the CNS and in some cases by pneumonia.

Development of tumours in mice chronically infected with herpes simplex virus.

Tumours developed in chronic infection lasting for 150--180 days in 39 (60%) of 65 mice infected with strain L2 of herpes simplex virus (HSV) type 1 and in 12 (20%) of 60 mice infected with strain 333 of HSV type 2. Similar results were obtained in 150 immunosuppressed mice chronically infected with HSV types 1 and 2. Pathomorphologically, the neoplasias in the first group (strain L2) were similar to adenocarcinoma and malignant lymphoma and in the second (strain 333) to lymphoma and angio- or fibrosarcoma. The respective HSV strains were isolated by cocultivation of blood leukocytes from chronically infected animals and cultures of the tumour cells with human embryo fibroblasts (HEF). HSV and Gross murine leukaemia virus antigens were detected in tumour cells by immunofluorescence and radioimmunoassay, respectively, and HSV antigen by immunofluorescence also in cultures of tumour cells and in cells of the brains, spinal cords, livers and spleens of the animals. HSV antibody was demonstrable in the blood serum from chronically infected tumour-bearing mice in a titre of 32.

[Pathomorphological characteristics of the experimental infection in animals infected with viruses of the rabies antigenic group]. / Patomorfologicheskie osobennosti éksperimental'noi infektsii u zhivotnykh, zarazhennykh virusami antigennoi gruppy beshenstva.

Comparison of pathomorphological lesions in the brains of white mice inoculated with viruses isolated in Africa from shrews, in America from bats, in Czechoslovakia from rodents (6 strains) and classified into the rabies group, with those observed in the same animal species infected with street rabies virus and virus of human acute encephalomyelitis (HAE) established the peculiar features of the reactive processes distinguishing these infections from each other. In contrast to the reactions after inoculation with street rabies virus and HAE, 24 hours after inoculation of white mice with Lagos bat, Ib An 27 377, 297 BF, 548 BF, 808 BF, 482 SG, 598 SG, and 638 SG strains hemorrhagic foci were observed; within 48 hours multiple perivascular cuffs were formed in the brain, and degeneration of the Ammon horn down to its disappearance and formation of multiple voids in the brain tissue were observed. Cytoplasmic inclusions in neurons of the cerebrum cortex and Ammon horn in the form of small paired formations with a pinpoint basophilic granule inside could be detected 24 hours postinfection. Later in the disease, the number of inclusions found diminished sharply.

[Localization of specific antigen in the organs of animals inoculated with different series of live measles vaccine]. / O lokalizatsii spetsificheskogo antigena v organakh zhivotnykh, privitykh razlichnymi seriiami zhivoi korevoi vaktsiny.

Specific antigen was identified by the immunofluorescent test in the walls of the brain blood vessels, in the neurons, and in the glial cells of albino newborn mice and Syrian hamsters inoculated subcutaneously with 4 different batches of live measles vaccine. The pathomorphological test of the brain tissue revealed mainly vascular disturbances. The data obtained testify to the presence of residual neurotropism in the attenuated measles virus (strain "L-16").

[Study of experimental chronic infection in mice caused by herpes simplex virus]. / Izuchenie éksperimental'noi khronicheskoi infektsii u myshei, vyzvannoi virusom obychnogo gerpesa

A chronic herpetic infection was produced in white random-bred mice by intradermal inoculation with the L2, 333 and K strains. The virus was regularly detected in the blood of the animals by the method of co-cultivation of leukocytes and human embryo fibroblasts for 70 days (the observation period). The virus was isolated from the brain, the spinal cord and viscera from the 3rd till the 30th postinoculation day. The virus antigen was found in leukocytes, and erythrocytes of the blood, the spinal cord and the brain from the 7th till the 70th day, and in the liver and spleen from the 7th to the 30th day. The titer of interferon in the viscera and serum of mice in the first 2-3 days after inoculation was 8 units, and subsequently 2 units. The interferon-producing activity of the blood leukocytes in mice was reduced (16-32 units) as compared to that in uninfected animals (64-128 units). The antibody titer at 7 days after incoulation was 1 : 32 in the blood serum of mice, at later intervals no antibody was found. Inflammatory and dengerative changes in the central nervous system and viscera of mice were detected throughout the observation period starting from the 7th day postinoculation.

[Chronic encephalomyelitis in white rats and guinea pigs]. / Khronicheskii éntsefalomielit u belykh krys i morskikh svinok

During a 2-year observation of white rats and guinea pigs infected with human acute encephalomyelitis virus a typical picture of the disease was observed with exacerbations and remissions quite characteristic of chronic forms of multiple encephalomyelitis and multiple sclerosis of man. The presence of the virus in animals and marked pathomorphological lesions in the central nervous system were shown not to prevent remissions. The evidence of association of chronic infection with long-term viremia is also important.

[Detection of Babes-Negri bodies in blood erythrocytes of rabid white mice]. / Ob obnaruzhenii telets Babesha-Negri v éritrotsitakh krovi bol'nykh beshenstvom belykh myshei

Large numbers of polymorphous dense Babes-Negri bodies were found in brain neurons of mice sick with street rabies and dying of it. Among blood cells filling the cerebral vessels of mice dead from rabies, erythrocytes containing small dense inclusions, Babes-Negri bodies, could be seen clearly.