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Biomedical subjects

L I Ravkina

Publications and source records attributed to L I Ravkina.

At least 19 recordsLinked to original sources
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

Reaction of mouse CNS cells to the scrapie agent in early stages of experimental infection.

Accumulation of the scrapie agent, histological lesions and cytometric parameters in layers III and V of the cerebral cortex and caudate nucleus were investigated in BALB/c mice during the incubation period of scrapie after intracerebral (i.c.) inoculation of the agent. The following cell parameters were determined: areas of the body, nucleus, and cytoplasm of neurons, concentration and amount of protein within the nucleus and cytoplasm. One month after i.c. inoculation, titre of the agent in the brain was 6.3 log LD50/g. Histological examinations of the infected brains revealed no lesions. Cytointerferometric studies showed a statistically significant increase in the size of the body, nucleus and cytoplasm of neurons, namely in the layer III of brain cortex. Increased amounts of protein were observed only in the nuclei of these cells. No such changes were found following i.c. inoculation of normal brain tissue used as a substrate for the agent.

Animals↗
PubMed1982

[Gliotoxic properties of multiple sclerosis and polyradiculoneuritis serum detectable in brain organ culture].

The blood serum of patients with disseminated sclerosis and polyradiculoneuritis was tested for gliotoxic effect in organ cultures of the brain of newborn cotton rats (Sygmodon hispidus). This effect was revealed in 18 out of 25 patients with disseminated sclerosis and in 9 out of 16 patients with polyradiculoneuritis. As for other diseases the gliotoxic effect was observed only in 3 out of 41 patients examined. The data obtained confirm the significance of the allergic mechanisms in the pathogenesis of demyelinization. It is suggested that the test for the serum gliotoxic effect should be used as a diagnostic criterion of the process activity in patients with disseminated sclerosis.

Adolescent↗
PubMed1981

[Acute meningoencephalitis in children caused by herpes simplex virus type I].

In 14 observations of acute meningoencephalitis in children mainly under 3 years of the age, data pointing to an etiological role of herpes simplex type I virus, were obtained on laboratory examination. Six children died, and in the rest 8 children who survived gross residua were observed. The morphological picture showed extensive colliquation necroses in the parietal, temporal, and less frequently, in occipital lobes and the Varolian pons. In 4 cases out of 6 intranuclear inclusions were detected. The incidence of herpetic encephalitis was 16%.

Acute Disease↗
PubMed1977

Latent infection and measles meningoencephalitis in Syrian hamsters.

A strain designated 42-Edmonston was isolated from the brain of a Syrian hamster 30 days after inoculation during the neonatal period with the reference "wild" measles virus strain Edmonston which produced a latent infection accompanied by production of measles antibody and insignificant pathomorphological changes. Intracerebral inoculation with the 42-Edmonston strain of newborn, one day-and 5-7-day-old Syrian hamsters resulted in the development of acute measles encephalitis with typical clinical symptoms and pathomorphological changes. It is suggested that selection and adaptation of a neurotropic measles virus variant probably had occurred in the course of virus persistence in the Syrian hamster brain.

Animals↗
PubMed1976

An attempt of treatment of malignant melanoma with bovine pineal tissue.

Seven incurable patients with disseminated malignant melanoma were injected (subcutaneously, sometimes intravenously) with homogenate of bovine pineal tissue. The daily injections of large quantities of pineal tissue appeared to be harmless for patients. Many-fold injections (during 9.5 months) of large quantities of pineal tissue (up to 3950 g) in 1 of 7 cases produced certain effect on subcutaneous metastases of malignant melanoma, i.e. causing reduction and even disappearance.

Adult↗
PubMed1976

[Determination of the gliotoxie and demyelinating properties of serum in organ cultures of brain in experimental allergic encephalomyelitis].

The report contains some results of a study of the blood serum taken from guinea pigs and macacus rhesus with allergic encephalomyelitis to a glyotoxic and demyelinizing effect in an organ culture of the brain in newborn rats and adult macacus rhesus. It was demonstrated that the test has a high specificity to a glyotoxic effect of the blood serum in experimental allergic encephalomyelitis and a less specificity to demyelinization in vitro. The authors describe in detail the method of studying the serum in organ brain cultures.

Acute Disease↗
PubMed1975

[Morphologic changes in the central nervous system of monkeys with chronic experimental allergic encephalomyelitis].

The authors attained a chronic experimental allergic encephalomyelitis in monkeys (macacca rhesus) by immunizing them with small doses of encephalitogenic mixtures. A histological study displayed large foci of demyelinization which had the appearance of plaques with gliosis and a developing gliofibrosis which is similar to those seen in disseminated sclerosis. The paper shows the existence of transitional forms between plaques and perivascular foci of demyelinization. The suggestion is made concerning the mechanism of the formation of plaques by a confluence of perivascular foci. There is also a constant lesion of visual nerves--inflammation and a massive demyelinization. The achieved data are considered as a model of disseminated sclerosis.

Animals↗