Our results indicate that carbon dioxide insufflation may cause catecholamine release during laparoscopic surgery. Careful monitoring of hemodynamics is mandatory at the beginning of the procedure.

To study the involvement of immune responses against Tax of human T-cell leukemia virus type 1 (HTLV-1) in the growth of and gene suppression in Tax (4,6,7,25,26) as well as induction of cellular genes including those for interleukin-2 (IL-2) and the IL-2 receptor (2,11,18), and the function of Tax is essential for HTLV-1 transformation of human T lymphocytes (5).In addition, Tax protein plays a role as an immunodominant target antigen recognized by HTLV-1 specific cytotoxic T lymphocytes (CTL) in most HTLV-1-infected individuals (14, 22). In HAM/TSP patients, a high virus load in peripheral blood lymphocytes is observed and a Tax-specific CTL response occurs at a high frequency (14), while low CTL activity has been reported for ATL patients (15). Therefore, a balance between Tax expression and Tax-specific CTL responses is thought to be an important determinant of the development of HTLV-1-related diseases (31). There has been controversy over whether Tax-specific CTL causes or prevents HTLV-1-related diseases, or whether a high viral load in the blood in HAM/TSP patients is a result or a cause of CTL. Recently, it was reported that there is a significant negative correlation between the frequency of Tax-specific CTL and the percentage of HTLV-1-infected CD4 ϩ T cells in the peripheral blood of HAM/TSP patients (10). These results seem to be in accord with the view that Tax-specific CTL protect against disease progression.Furthermore, there remains another unanswered question as to the long latency before the onset of HTLV-1-related diseases. It has been suggested that the latent period involves mutations in the genomes of infected lymphocytes, some part of which have been attributed to the function of Tax protein (13,32), and selection by the host immune system. In fact, it was demonstrated recently that the HTLV-1 tax gene in most leukemic cells from ATL patients accumulated various types of mutations leading to viral escape from the host immune system (9). For analysis of events in such a latent period, it is necessary to establish an animal model in which the growth of HTLV-1-infected lymphocytes and the host immune system reach a certain balance in vivo. Since HTLV-1 cannot replicate well in mouse cells, a certain strain of rat (17) and SCID mice (27) only have been used as animal models of HTLV-1-related diseases. Mice, however, have a great advantages as model animals, and normal immune reactivity is required to investigate the onset of HTLV-1-related diseases.To gain insights into the mechanisms underlying the long latency and onset of HTLV-1-related diseases, we established a simple animal model for investigating the interaction between Tax-expressing cells and Tax-specific immune responses involving mice and syngeneic T lymphoma cells expressing Tax. Focusing on Tax and anti-Tax immune responses, we demonstrated that Tax expression under the control of the HTLV-1 long terminal repeat (LTR) was transiently suppressed in vivo, resulting in a kind of equilibrium between Tax-specific immune responses and ...

Gene expression in Rat-1 fibroblast cells transformed by Tax from human T-cell leukemia virus type 1 was studied using the reverse transcriptase polymerase chain reaction differential display technique. The analysis revealed eight genes that were upregulated and one gene that was suppressed in Tax-transformed cells. Interestingly, at least four of the upregulated genes were interferon-stimulated genes. Promoter analysis of the 2',5'-oligoadenylate synthetase gene, which was activated in both Tax-transformed Rat-1 cells and primary adult T-cell leukemia cells, demonstrated that Tax indirectly activates its interferon-responsive enhancer element in a nuclear factor-kappaB pathway-dependent manner, indicating a close association of interferon signaling with the transformation by Tax.

We report a case of invasive bladder cancer in which cancer dissemination occurred through a perforation of the vesical wall during transurethral resection of the tumor. A radical cystectomy was performed 1 month later and several clusters of viable cancer cells were histologically identified in a fibrous foreign body granuloma in the paravesicular adipose tissue of the lymphadenectomy specimen. The patient received adjuvant chemotherapy, but developed right inguinal lymph node metastasis 21 months after cystectomy. Int

Our results indicate that carbon dioxide insufflation may cause catecholamine release during laparoscopic surgery. Careful monitoring of hemodynamics is mandatory at the beginning of the procedure.