Kapronczay Károly szerk.: Orvostörténeti Közlemények 182-185. (Budapest, 2003)

TANULMÁNYOK - ARTICLES - GOSZTONYI, Georg: Stephan Környey's contribution to the study of encephalitides. (Környey István hozzájárulása az. agyhártyagyulladás kutatásához.)

The evaluation of the experimental results allowed Pette, Demme and Környey to take a stand on the mechanism of spread of the polio virus. According to their view, and in contrast to that of other authors, the virus travels to the central nervous system (CNS) not in the lymph vessels of the peripheral nerves, but along the axons of the nerve fibres, i.e., intraaxonally. Numerous data support the notion that also within the CNS the neural tracts are the pathways of virus spread. Nevertheless, they left the possibility open that the virus can reach remote areas also along the (at that time hypothesised) lymph channels of the CNS and by the cerebrospinal fluid. Following a hematogenous infection beside the predilectionally involved areas a few other CNS areas also become involved that remain spared in case of neural inoculation. In a review Környey (1933a) compared the histological picture of experimental poliomyelitis with that of human poliomyelitis and assessed an almost complete identity of the processes in the two species. In the course of the study of further polio-cases Környey examined the character and extension of the mesodermal reaction, and the system-selectivity of the poliomyelitic process (Környey, 1933b). In this study he lays down the principle of gangliocellulotropism, viz., gangliocytotropism, according to which the poliovirus replicates exclusively in ganglion cells, and within the ganglion cell systems it disposes towards certain systems of a predilectional affinity (system-selectivity, "' Systemelektivitdt"). This principle manifests itself in the fact that in the spinal cord the big motor neurons are destroyed, while the small and middle-sized ganglion cells, and those of the lateral horn and of the Clark column remain spared. In the cerebral cortex the neurons of the precentral areas, and, in particular, those of the area gigantopyramidalis become selectively involved. In a further study Pette and Környey (1935) reported on their observations on experimental Borna encephalitis. The Borna disease is an endemic encephalitis of horses and sheep in southern Germany, which had been classified into the group of multifocal polioencephalitides (Spatz, 1930) with its distribution pattern similar to that of encephalitis lethargica [von Economo] (Seifried and Spatz, 1930). Borna disease advanced in the foreground of the virologists' interest in the 80ies and 90ies of the previous century, when it became evident that human infections by this virus also occur and that this agent has most probably a role in the evolution of affective psychoses (Bode and Ludwig, 2001). Borna disease virus is an agent with most pronounced neurotropic features, which, according to recent molecular genetic studies, has been classified in the new mononegavirales order of the RNA viruses, and in the family of Bornaviridae (Pringle, 1995; de la Torre et al. 2000). The early experimental study of Pette and Környey (1935) yielded important data to understand basic pathogenetic mechanisms of this disease. Following experimental infections of rabbits and monkeys they analysed the extension and histologic characteristics of the process. They established that the principle of system selectivity is valid also in the Borna disease. As to the mechanism of spread of the agent, they advocated the neural route. Környey returned to Hungary in 1935. His friend, Desiderius Miskolczy, had just been appointed to the chair of neurology and psychiatry at the University of Szeged. Környey became associate professor at the University of Szeged, and, later on, accompanied Miskolczy to Kolozsvár and Marosvásárhely (Mérei, 1994). In these years, beside his clinical neurological and neurosurgical activity, Környey could not carry on experimental work, but his interest in encephalitides endured. Based on his earlier work and experience he wrote