[Primate models of human viral hepatitis].

The paper summarizes the updates available in the literature and the authors' own data on the etiology of hepatitis, its models, and experimental studies on susceptible simian types. A comparative analysis of the etiological agents--the causative agents of simian and human hepatitis will give a better insight into the evolution of its viruses.

[Viral hepatitis E. The problems of its study].

The paper presents the results of investigations of hepatitis E (HE), which have been made at the Department of Viral Hepatitides, M. P. Chumakov Institute of Poliomyelitis and Viral Encephalitides, Russian Academy of Medical Sciences. M. S. Balayan's discovery of hepatitis E virus permitted etiological interpretation of the cases of so-called non-A, non-B hepatitis with its fecal and oral transmission. The detection of antibodies to HE virus among different groups of the population of Russia (i.e. a hepatitis E nonendemic region of the world) suggests that they are frequently detected in the absence of disease notification. The fact that viral HE RNA has been detected in the pigs and wild boars inhabiting in the country is evidence in favor of an assumption that the virus is spread among these animals. The hypothesis for HE as a zoonosis is discussed in the paper.

[Prevalence of antibodies to hepatitis E virus among residents of different climate and geographic zones of Russia Federation]. / Chastota vstrechaemosti antitel k virusu gepatita E u naseleniia razlichnykh klimatogeograficheskikh zon Rossiiskoi Federatsii.

The detection frequency of antibodies to Hepatitis E Virus (HEV) was studied in residents of the South and of the Middle European Part of the Russia Federation as well as of Siberia. Antibodies to HEV were most often found both in patients with hepatic pathologies and in subjects with diseases unrelated with a primary hepatic lesion, in particular, in patients with skin and venereal diseases and with HEV. A higher concentration of antibodies to HEV was noted also in blood donors, medical personnel and isolated communities, like prisons or psychiatric clinics. A correlation was established between the rate antibodies to HEV are registered and such risk factor as contacting with blood or a gross violation of the hygienic rules.

[An unusual course of viral hepatitis A in children]. / Neobychnoe techenie virusnogo gepatita A u detei.

To determine the present-day specific clinical features of viral hepatitis A (HA) in children, observation on 447 children aged 1 year and 10 months to 14 years with verified HA monoinfection was carried out. At the season of 1993 essential differences were observed in the clinical picture of HA: the disease took a more severe course with the prevalence of medium-severe (59.3%) and severe (3.6%) forms of this infection, a tendency to a prolonged convalescence period and fermentative aggravations, an increase in the occurrence of cholestatic forms. One of the causes of this phenomenon may be attributed to changes in the properties of the infective agent.

[Further study of experimental hepatitis E in piglets]. / Dal'neishee izuchenie éksperimental'nogo gepatita E u porosiat.

Experimental infection of piglets with a fecal pool containing hepatitis E virus (HEV) strains Osh-25 and Osh-228 confirmed previous results obtained with HEV strain Osh-205 on susceptibility of these animals to hepatitis E. A biphasic increase of transaminase activities, histopathologic changes in the liver, virus excretion with feces were observed in the animals. The genome of viral particles in piglet feces conformed, at least partially, to human HEV RNA. Ultrastructural abnormalities of piglet hepatocytes resembled those in primates with experimental hepatitis E. The number of positive results (during follow-up of the particles and HEV RNA in various organs of experimental animals) was the highest on day 10 after infection. Both the particles and HEV RNA were present in the lymphoid tissue over the entire follow-up period, from day 5 to day 15 postinfection.

[An experimental infection in lambs by the hepatitis E virus]. / Eksperimental'naia infektsiia iagniat virusom gepatita E.

Lambs were experimentally infected with a pool of 10% hepatitis E (HE) patient fecal suspension containing HE virus (HEV) isolates Osh-225 and Osh-228 which caused an infection closely resembling experimental HE in primates. Clinical manifestations consisted of acute biochemical and histological hepatitis, virus shedding in feces, the presence of virus-like particles in the peripharyngeal lymph nodes and the contents of small intestine, of HEV RNA in the parenchymal organs of lambs. Susceptibility of lambs to HEV derived from the infected piglets and the possibility of passaging the piglets' HEV in lambs was demonstrated. This passaging led to shortening of the incubation period.

[The antiviral action of a modified bacterial ribonuclease]. / Izuchenie antivirusnogo deistviia modifitsirovannoi bakterial'noi ribonukleazy.

The antiviral activity of a bacterial ribonuclease conjugate with chitosane of Kamchatka crab (in a form of water soluble chito-oligosaccharides) has been studied. The conjugate inhibitory activity for A and B viruses as well as to Sindbis arbovirus in tissue cultures is shown. The preparation efficiency at intramuscular and intranasal administration was observed at experimental influenza infection of white mice.

[Experimental hepatitis E infection in piglets]. / Eksperimental'naia infektsiia gepatita E u porosiat.

A sample of patient's faeces containing virus-like particles (VLP) of 27-34 nm was obtained during an outbreak of hepatitis E in the Kirghiz SSR. The identity of the VLP to hepatitis E virus and etiological association with the disease were demonstrated by immune electron microscopy and infection of Macaca fascicularis monkeys. This isolate of hepatitis E virus is able to induce experimental infection in domestic piglets which was very similar to experimental hepatitis E in primates when infected orally, intravenously and by the combined routes. The clinical manifestations included acute biochemical and histological hepatitis, excretion of hepatitis E virus in faeces, icteric sclerae and skin, hepatitis virus presence in the material from mesenteric lymph nodes. Immunosuppression aggravated hepatitis E infection in piglets. Piglet-to-piglet transmission of hepatitis E virus was demonstrated. During passages of the virus in piglets a shortening of the incubation period and the absence of jaundice was observed.

[Development of an infection in monkeys as a result of their sequential natural and experimental exposure to the hepatitis A virus]. / Razvitie infektsii u obez'ian v rezul'tate posledovatel'nogo estestvennogo i éksperimental'nogo zarazheniia ikh virusom gepatita A.

The development of spontaneous outbreak of hepatitis A (HA) among African green monkeys kept under strict isolation conditions was studied. It was shown that in the case of introduction of HAV the infection involved all the susceptible monkeys, running a course with and without any increase in the level of activity of serum alanine aminotransferase (ALT) After inoculation of commercial gamma-globulin only the infection without the ALT activity increase developed and some monkeys had no signs of HA at all. Experimental reinfection with HAV was produced in monkeys having anti-HAV titres of less than or equal to 1:3500.

[Economic bases of treatment intensification at specialized oncological facilities]. / Ekonomicheskoe obosnovanie intensifikatsii lecheniia v spetsializirovannom onkologicheskom uchrezhdenii.

The purpose of the study was to work out economic rationale for intensifying treatment at specialized oncological establishments. Modern modalities of cancer treatment require patients to be admitted to specialized hospitals. However, at present nearly half of them receive treatment in general medical establishments which, as a rule, do not have facilities for combined and complex treatment. It is estimated that shifting patient examination emphasis from hospital to outpatient clinic might increase the clinical bed turnover by 6.7% which, in turn, will allow to treat 43000 patients more in specialized hospitals every year. The introduction of such scheme will cost 6.8 times less than commission of new beds required for management of the equivalent number of cancer patients.

[Susceptibility of Macaca rhesus to infection with hepatitis A virus strains isolated from man and monkeys]. / Vospriimchivost' makak rezusov k zarazheniiu shtammami virusa gepatita A, vydelennymi ot cheloveka i obez'iany.

The results of infection of Macaca rhesus monkeys with hepatitis A virus (HAV) strains isolated from monkeys and man are presented. After inoculation of monkeys with human NAV strains the infection could not be reproduced whereas simian HAV strains were found to be pathogenic for M. rhesus monkeys both on experimental inoculation and during natural contacts with infected monkeys in the animal house.

[Spontaneous hepatitis in the crab-eating macaque exposed to immunodepressants]. / Spontannyi gepatit u iavanskoi makaki, podvergnutoi vozdeistviiu immunodepressantov.

A case of spontaneous hepatitis was detected in experiments aimed at working out the conditions for reproduction of the immunosuppressed state in Macaca fascicularis with the purpose of subsequent infection of these monkeys with non A non B hepatitis virus transmitted by the fecal-oral route. One of 6 monkeys at the 8th day of the experiment was found to have developed an increase in the level of serum aminotransferases which grew progressively reaching high values by day 14. Fecal specimens from this monkey collected on the 5th day and later contained spherical virus-like structures 27 nm in diameter, antigenically identical with hepatitis A (HAV) virus. In the other 5 monkeys, no similar structures were found in fecal specimens throughout the experiment. The monkey with the signs of hepatitis was sacrificed on the 16th day of experiment, i. e. on the 8th day from the onset of hyperenzymemia. Immune electron microscopy of extracts of hepatic tissue and fecal specimens collected from this monkey has revealed 27 nm particles antigenically identical with HAV. The bulk of viral particles from the liver sedimented in cesium chloride buoyant density zone of 1.32 g/cm3, and from fecal specimens in the zone of 1.36 g/cm3. In the liver of this monkey, histological changes were found which are observed in acute hepatitis, and HAV antigen in hepatocyte cytoplasm was detected by the fluorescent antibody technique. It is suggested that the spontaneous disease of this monkey was due to natural infection with HAV which could be provoked by experimental immunosuppression.