In Vitro Behaviour of Tissue of Adult Mammalian Central Nervous System

Tissue of the central nervous system of adult rhesus monkeys has been successfully maintained in vitro by a culture technique that had been used for the cultivation of highly differentiated tissues. Neurons and some glial cells survived for 84 days in a chemically-defined, protein-free medium which was formulated in the course of this study. Attempts to Infect motor neurons in Implanted fragments of the anterior horn and cerebral cortex with poliovirus type 1 were unsuccessful. A cell-strain was established from trypsinized adult rhesus monkey cerebral tissue. The cultures, comprising choroid epithelial cells, astrocytes and microglial cells, were maintained in vitro by serial subcultivations. The cells retained their normal karyotype but degenerated after about six weeks. No endogenous virus was detected. The cultures supported the growth of a number of viruses. Echovirus type 11 and Coxsackie viruses types A7 and B3 produced cytopathogenic changes typical of the picornavirus group. Reovirus type 1 produced 1ntracytoplasm1c Inclusion bodies, and giant-cells were formed in monolayers Infected with vaccinia and herpes simplex virus. Vaccinia-infected cells were localised by haemadsorption. Vaccinia virus affected all cell-types Indiscriminately while with the other viruses, the choroid epithelial cells succumbed to Infection before the other cell types. Serological relationship between Coxsackie viruses A7 and B3 was determined by complement-fixation test. Coxsackie A7 antigen cross-reacted with anti-Coxsackie B3 serum, but no reaction was detected between Coxsackie B3 antigen and Coxsackie A7 antiserum. A hypothesis has been postulated for the antigenic structures of the two viruses to explain for this non-reciprocal cross-reaction. The potential usefulness of the newly-described cell strain Includes the study of neurotropic viruses Including the "slow viruses" and the primary Isolation of viruses from clinical materials

Chronic hepatitis in multiple virus infection: histopathological evaluation

The frequency and histological pattern of multiple hepatitis virus infection was studied in 161 Italian patients who had consecutively undergone liver biopsy from 1989 to 1991. The histological features were compared with that of infection with a single virus. Thirty-nine per cent of patients had evidence of past or present multiple infection, the commonest of which was hepatitis C virus (HCV) in patients with evidence of previous infection with hepatitis B virus (HBV). In general, the severity of the histological pattern of each viral infection was maintained even when more than one virus was involved; there was neither exacerbation nor diminution of the histological changes. The delta-virus (HDV) was not associated with severe necro-inflammatory lesions, but HDV-positive patients were few in this cohort. Lymphoid follicle formation (a putative histological marker of HCV infection) was also found in a high proportion of HCV-negative patients but expressing much HBcAg or HDAg in liver tissue. Possible explanations for this finding are that follicles are relatively non-specific for HCV infection, or that these cases represent HCV infection with false-negative serology. The results of this study suggest that multiple hepatitis virus infection is common in the population investigated and that HBV and HCV co-infection cannot be reliably diagnosed histologically. Whether double infection with these viruses influences the cirrhotic evolution of the liver lesion remains unclear