X-gene product antagonizes the p53-mediated inhibition of hepatitis B virus replication through regulation of the pregenomic/core promoter.

Employing the glutathione S-transferase column retention method and far Western analysis, we found a physical association between tumor suppressor p53 and the hepatitis B virus X-gene product, which led us to study the function of observed interaction in relation to viral propagation. In the cell culture-based in vitro replication system, expression of p53 resulted in dramatic inhibition of viral replication, and this inhibition was relieved by the coexpression of the X-gene product in a dose-dependent manner. Furthermore, the activity of pregenomic/core promoter, responsible for the synthesis of pregenomic RNA, was almost completely inhibited upon expression of p53, and as in the replication assay, the inhibition was rescued by the coexpression of the X-gene product in a dose-dependent manner. Based on these results, we propose that the ratio of X-gene product to p53 is an important factor determining the fate of viral replication through modulation of the pregenomic/core promoter.

Intussusception: evolution of current management.

The records of 583 children who were treated for intussusception at the Children's Hospital of Buffalo in the period 1930-1985 were reviewed. Following a change in management in 1970 from operative treatment to hydrostatic reduction of the intussusception by barium enema, two main groups are defined. In earlier years 95% of patients underwent operative reduction whereas in the latter period 92% had barium reduction attempted. The remaining 8% in this group had clinical contraindications for hydrostatic enema attempt. Ten percent had pathological lead points. Recurrent intussusception occurred in 50 cases (8.5%), 66% following barium enema reduction and 33% after surgery. The mortality in the earlier group was 3.9% and 1.3% in the latter group. No deaths occurred in patients treated successfully with barium enema reduction, and there were no deaths in the children with simple uncomplicated intussusception requiring surgery.

Lymphoid cell populations in splenectomized and nonsplenectomized SJL/J mice bearing Hodgkin's disease-like reticulum cell sarcoma.

Using the reticulum cell sarcoma (RCS) of the SJL/J mouse as a model for Hodgkin's disease, the effects of tumor growth and splenectomy on the T-cell and B-cell populations were evaluated. Although splenectomy improved survival and reduced gross observable tumor growth in secondary tumor sites, no effect on T-cell and B-cell populations was detected. We conclude that tumor growth appears to be undetected by the immune system; previously reported immunosuppression in RCS-bearing mice must be due to functional changes and not cell population changes; and splenectomy contributes to survival and suppression of tumor cell growth in secondary sites.