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.)

hodologic factors (course and connections of CNS tracts), and at the estimation of the extension of the encephalitic process more emphasis had to be laid on the time factor. It is the momentary equilibrium of the time factor and of the neurotropism, which determines the extension of the process in an actual phase of the encephalitis. The most interesting part of the review is represented by the treatment of the neural spread of viruses. Környey questioned, whether the fact that a virus selects the neural route instead of the haematogenous one, is not the manifestation of the general neurotropism? While analysing data of the literature and personal observations he concluded - in harmony with Goodpasture's views (Goodpasture, 1925) - that the substrate of the neural spread of viruses was the axis cylinder of nerve fibres. As to the mechanism of the axonal spread, Környey raised the necessity of a moving force ("treibende Kraft") or of a fluid flow ("Flüssigkeitsströmung") at a time, when the concept of the axonal transport had hardly been raised in neurobiology. In the spread of the virus from the periphery to the spinal ganglion simple mechanical factors had to play a role. Later on, most probably the principle of special neurotropism decides, which CNS tract or tracts are selected by the virus. Following injection of poliovirus into the vitreous body, the retina and the optic centres remained intact, while the ciliary ganglion and the oculomotor nuclei were seriously involved. He also pointed out that during the axonal spread there was no viral replication and the spread of virus along a CNS tract did not necessarily leave morphological signs behind. According to his view, poliovirus spread within the CNS along neural tracts, and not by the cerebrospinal fluid. The observation of Bodian and Howe (1940), according to which after cerebral inoculation in monkeys the poliovirus arrived to the distal segments of the spinal cord even after transsection, Környey interpreted so that the virus used the paravertebral chain of sympathetic ganglia to reach the caudal spinal cord segments. These pathogenetic considerations are valid even today. In his study entitled The problems of the initial phase of poliomyelitis, published already in 1946 from the Bolyai University at Marosvásárhely, Környey laid strong emphasis on epidemiological factors. He called attention to the demonstration of the virus in the stool and in the sewage water, and to the fact that the direction of the spread of the epidemic followed the streaming direction of the rivers. The virus entered the human organism through the nose or the gastro-intestinal tract. He called attention to the observation that poliomyelitis presented not infrequently following tonsillectomy, and then in the severe bulbar form. Környey published a short survey article on viral meningitides and encephalitides in L'Encéphale, in 1949, already chairing the Department of Neurology and Psychiatry at the University of Pécs. In this study with strong emphasis on clinical features he treated not only the benign lymphocytic viral meningitides, but - to support differential diagnostic activity - he also reviewed the bacterial meningitides presenting with a predominantly lymphocytic pleocytosis. Among the virus diseases involving the neural parenchyma he particularly emphasised the poliomyelitis and the panencephalitides. A veterinary viral disease, the infectious paralysis of swine (Teschen disease), is in many respects similar to the human poliomyelitis. Környey had an opportunity to perform experimental studies on this swine encephalitis with Pál Elek (Környey and Elek, 1952a and b). The histological study of the disease revealed that in this illness a multifocal polioencephalitis with predominance in the brain stem could be assessed with similarities to the poliomyelitis, rabies and the Borna disease. In the Teschen disease the inflammatory infil-