The animal model for the study of B encephalitis was established by injecting Jin Wei Yan 1 strain of B encephalitis virus into the peritoneal cavity of mice. All the mice injected demonstrated the histological features of the disease. Special attention was paid to the ultrastructural changes of the granular cells, the Purkinje cells and the Golgi cells in the cerebellum, and the findings in these cells were compared with those of the nerve cells in the cerebral cortex, dience-phalon and tnesencephalonIt was found that endoplasrnic reticulum could appear in the nerves infected by B encephalitis virus. A radiating structure was-usually formed by the viral replication multivesicular bodies with microvesiculo-tubular body as its center. The morphological changes and the developmental sequence as well as the significance of this radiating structure were discussed.In the late stage of the infection, viral particles were found in the nuclei of a part of the necrotic cells. It was likely that the viral particles entered the nuclei by way of cytoplasm. Our observation confirmed the Chen Liming's hypothesis that viral particles can be formed in the perinuclear space. The way that the viral particles were evacuated from the infected nerve cells observed in this study was in agreement with that reported by Chen Liming, but most of the viral particles left the infected nerve cells through the axons.

The beta and gamma chain gene rearrangements of the T-cell receptors(TCR)were studied with Southern blot hybridization and polymerase chain reaction in 13 cases of non-Hodgkin's lymphoma with T-cell phenotype.It was found that 11 out of the 13 cases(86%)exhibited TCR beta gene rearragnement and 12 out of the 13(91%)displayed TCR gamma gene rearrangement.The findings suggest that gene rearrangements are more sensitive and specific markers to establish T-cell monoclonality and lineage and helpful to the morphological diagnosis and immunophenotyping for non-Hodgkin's lymphoma.

The histological and ultrastructural changes in cerebellum of mice exposed whole-body irradiation with high doses of 60Coy-ray were studied in this paper. The animals suffered from acute radiation sickness of CNS form, intermediate form and intestinal form after 16000, 8000 and 4000 rads irradiation respectively. The nuclear shrinkage of the cerebellar granular cells was the most prominent change after irradiation. The cellular necrosis was found only in individural cells. The shrinkage of nucleus, different from necrosis, with characteristic ultrastructural features, tended to recover as manifested by the appearance of nucleolus, increase of free polysomes and well development of Golgi apparatus. It was considered that the cerebellar granular cells were rather resistent to, the radiation. Some pathological changes of small blood vessels in cerebellum were also observed, but was not responsible for the degeneration of the neurons.

In order to assess the significance of human malignancy-associated nucleolar antigen P24 in the diagnosis of tumors,552 specimens of human tissues were stained and observed with immuno - fluorescent and ABC methods using anti-P24 monoclonal antibody MA2.It was found that P24 was positive in the nucleolus of 97% cases of malignant tumors and in 50% of atypical hyperplastic tissues but negative in 98.6% cases of benign tumors and in all the normal or nontumorous tissues.On the basis of these findings,it is believed that P24 is highly specific to malignant tumors and will be a useful marker for the differential diagnosis between malignant and benign tumors.