Biomedical subjects

Toshiki Rikiyama

Publications and source records attributed to Toshiki Rikiyama.

9 recordsLinked to original sources

PubMed2004

Apoptosis induced by adenovirus-mediated p14ARF expression in U2OS osteosarcoma cells is associated with increased Fas expression.

The INK4A/ARF locus on chromosome 9 is a tumor suppressor gene frequently mutated in human cancers. In order to study the effects of p14ARF expression in tumor cells, we constructed a recombinant adenovirus containing p14ARF cDNA (Adp14ARF). Adp14ARF infection of U2OS osteosarcoma cells which has wild type p53 and mutant p14ARF revealed high levels of p14 (ARF) expression within 24h. In addition, Adp14ARF-mediated expressing of p14 (ARF) was associated with increased levels of p53, p21, and mdm2 protein. Growth inhibition assays following Adp14ARF infection demonstrated that the growth of U2OS cells was inhibited relative to infection with control virus. Furthermore, TUNEL analysis as well as PARP cleavage assays demonstrated that Adp14ARF infection was associated with increased apoptosis in U2OS cell line and that it was associated with Adp14ARF induced overexpression of Fas and Fas-L. Addition of Fas-L neutralizing antibody NOK-1 decreased Adp14-mediated cell death, indicating that p14 (ARF) induction of the Fas pathway is associated with increased apoptosis. The finding that Adp14ARF infection did not induce Fas expression in U2OS/E6 and MCF/E6 cells suggests that wild type p53 expression may be necessary for Adp14ARF-mediated induction of Fas. The observation that overexpression of p53 by Adp53 infection in MCF-7 does not induce increased Fas protein levels nor apoptotic cell death suggests that p53 overexpression is required but not sufficient enough for apoptosis. These studies suggest there are other mechanisms other than induction of p53 in ARF-mediated apoptosis and gene therapy using Adp14ARF may be a promising treatment option for human cancers containing wild type p53 and mutant or deleted p14 expression.

Adenoviridae↗

PubMed2004

New reconstructive procedure after intestinal resection for Crohn's disease: modified side-to-side isoperistaltic anastomosis with double Heineke-Mikulicz procedure.

Although side-to-side isoperistaltic anastomosis is a useful strictureplasty technique when long segments of intestinal stenosis complicate Crohn's disease, concerns have been raised regarding disease recurrence adjacent to the anastomosis. We performed side-to-side isoperistaltic anastomosis without spatulated intestinal ends as a method of reconstruction after intestinal resection for Crohn's disease; both intestinal ends were transversely closed like a Heineke-Mikulicz-type strictureplasty. With this procedure, the luminal diameter proximal and distal to the anastomosis became wider than the original diameter of the intestine. This new procedure, which we refer to as the "modified side-to-side isoperistaltic anastomosis with double Heineke-Mikulicz procedure" could become an alternative operation after intestinal resection in persons with Crohn's disease, although long-term outcome analysis is necessary.

Anastomosis, Surgical↗

PubMed2003

GCF2: expression and molecular analysis of repression.

GC-binding factor 2 (GCF2) is a transcriptional repressor that decreases activity of the epidermal growth factor receptor (EGFR) and other genes. We have mapped the gene for GCF2 by fluorescence in situ hybridization (FISH) to chromosome 2q37. Sequence analysis of the GCF2 gene and cDNA showed that the gene consists of eight exons and introns and spans 73 kbp of DNA. Northern blot analysis showed that GCF2 mRNA was differentially expressed in many human tissues and cell lines. GCF2 mRNA was expressed as a 4.2 kb mRNA in most human tissues with the highest expression level in peripheral blood leukocytes and lowest expression in brain and testis. Additional transcripts of 6.6, 2.9 and 2.4 kb were found in some tissues but the only transcript detected in cancer cell lines was 4.2 kb with high levels found in seven Burkitts' lymphoma cell lines. Western blot analysis showed that GCF2 protein is present at high levels in Burkitts' lymphoma and several other cancer cell lines. GCF2 was found in both nuclear and cytoplasmic compartments in cells. Deletion mutants of GCF2 revealed that amino acids 429-528 are required for both DNA binding and repression of the EGFR promoter. Furthermore, GCF2 was able to substantially decrease activator protein 2 (AP2) enhancement of the EGFR promoter. Thus, GCF2 is a transcriptional repressor overexpressed in cancer cell lines with a role in regulating expression of the EGFR.

Adaptor Protein Complex 2↗

PubMed2003

Analysis of the epidermal growth factor receptor promoter: the effect of nuclear factor-kappaB.

The epidermal growth factor receptor gene is highly regulated and responsive to extracellular stimuli that control cell growth. We have identified five putative nuclear factor-kappaB (NF-kappaB) binding sites within the epidermal growth factor receptor (EGFR) promoter region by sequence analysis. We have analyzed the potential role of NF-kappaB family members in the regulation of the EGFR transcription. Electrophoretic mobility shift analysis demonstrated that the p50 and p49, subunit proteins of the NF-kappaB, bound to the EGFR promoter at four out of five of these sites. However, it was found that NF-kappaB could not transactivate the EGFR by cotransfection experiments with each NF-kappaB subunit, using p50, p65 and c-Rel and an EGFR promoter luciferase reporter. Treatment of cells with tumor necrosis factor (TNF)-alpha, which could degrade the I-kappaB and then result in translocation of NF-kappaB to nucleus, did not enhance EGFR promoter reporter gene transcription. Also, TNF-alpha did not induce EGFR expression at the protein level. These results indicate that even though purified NF-kappaB can bind to the putative sites, there is no evidence that NF-kappaB transactivates the EGFR promoter region.

3T3 Cells↗

PubMed2002

Recombinant adenovirus-mediated p14(ARF) overexpression sensitizes human breast cancer cells to cisplatin.

p14(ARF), the alternative product from the human INK4a/ARF locus, is one of the major targets for alterations in the development of human cancers. Overexpression of p14(ARF) results in cell cycle arrest and apoptosis. To examine the potential therapeutic role of re-expressing p14(ARF) gene product in human breast cancer, a recombinant adenovirus expressing the human p14(ARF) cDNA (Adp14(ARF)) was constructed and used to infect breast cancer cells. Five days after infection, Adp14(ARF) had considerable cytotoxicity on p53-wild-type MCF-7 cells. A time-course study showed that Adp14(ARF) infection of MCF-7 cells at 100pfu/cell increased the number of cells in G0/G1 phase and decreased that in S and G2/M phases. The presence of apoptotic cells was confirmed using the TUNEL assay. Adp14(ARF)-mediated expression of p14(ARF) also resulted in a considerable increase in the amounts of p53 and its target proteins, p21(WAF1) and MDM2. Furthermore, the combination treatment of MCF-7 cells with Adp14(ARF) and cisplatin resulted in a significantly greater cell death. Together, we conclude that p14(ARF) plays an important role in the induction of cell cycle arrest and apoptosis in breast cancer cells and recombinant adenovirus-mediated p14(ARF) expression greatly increases the sensitivity of these cells to cisplatin. These results demonstrate that the proper combination of Adp14(ARF) with conventional chemotherapeutic drug(s) could have potential benefits in treating breast cancer that carries wild-type p53 gene.

Adenoviridae↗

PubMed2002

[S4 S5 subsegmentectomy of the liver for gallbladder carcinoma].

Although innovations have occurred in imaging technology and surgical techniques, carcinoma of the gall-bladder still has a poor prognosis. Since the 1960s, we have performed extended cholecystectomy in patients with gallbladder cancer. Extended cholecystectomy is a safe and common treatment for advanced cancer, but the extent of necessary hepatic resection has not been established. In 2000, we reported that the gallbladder veins infused into the intrahepatic portal venous branch, mostly at P4 and P5(96.7%). Based on those results, we now perform resection of the lower part of segment 4(S4a) and segment 5 for advanced cancer with subserosal invasion and/or negligible direct invasion to the parenchyma of the liver. S4aS5 subsegmentectomy is thought to have a clear advantage over extended surgical margins. This procedure can remove almost all the area perfused by the gallbladder veins and as a results, it may also remove latent and occult metastatic foci. The steps in the procedure are as follows: 1) lymph nodes cleaning of the posterior of the pancreas head; 2) skeletonization of the hepatoduodenal ligament; 3) identification and ligation of the lower branch of P4; 4) identification of the boundary between the anterior and posterior segment; and 5) hepatic resection with the plate of the gallbladder. Since 1991, we have performed S4aS5 subsegmentectomy in 12 patients with gallbladder cancer. Although the follow-up period is short, it is thought that the outcome of this procedure is better than that of extended cholecystectomy because of the low mortality and morbidity rates.

Aged↗

PubMed2002

[Laparoscopic biliary surgery].

Laparoscopic cholecystectomy has become the standard treatment for patients with symptomatic gallbladder disease. However, there is a substantial proportion of patients in whom laparoscopic cholecystectomy cannot be successfully performed, and conversion to open surgery is required because of technical difficulties or complications. The incidence of bile duct injury has increased in laparoscopic cholecystectomy. Meticulous dissection and intraoperative cholangiography could significantly reduce the rate of that injury. Laparoscopic cholecystectomy for acute cholecystitis is still controversial because of surgical difficulty. In our experience, early laparoscopic cholecystectomy is a beneficial option for patients with acute cholecystitis, and it may even be safe in the acute stage. A better alternative for high-risk early operation and septic cases is percutaneous transhepatic gallbladder drainage. The coexistence of gallbladder cancer should be ruled out and preoperative diagnosis should be done carefully. Laparoscopic management of common bile duct (CBD) stones has many advantages. However it has been reported to be demanding and time-consuming to perform, which limits its widespread adoption. In our experience with 258 patients, laparoscopic CBD exploration was feasible for almost all CBD stones. The technical difficulties associated with laparoscopic CBD exploration could be overcome with the development of suitable equipment and increased expertise.

Cholecystectomy, Laparoscopic↗

PubMedDate not supplied

A new free radical scavenger, edaravone, ameliorates oxidative liver damage due to ischemia-reperfusion in vitro and in vivo.

Ischemia-reperfusion injury causes oxidative stress producing reactive oxygen species, which is a serious problem linked to morbidity and mortality in liver surgery. We investigated the effects of edaravone, a new free radical scavenger, on liver oxidative stress in vitro and in vivo. We employed a hypoxia-reoxygenation model of primary cultured hepatocytes using an AnaeroPack (Mitsubishi Gas Chemical Co., Tokyo, Japan). Hepatocytes were exposed to 3 or 4 hours of hypoxia and then returned to oxygenation. We analyzed the time course changes of aspartate aminotransferase (AST), phosphatidylcholine hydroperoxide (PCOOH), and adenosine triphosphate (ATP) content in hepatocytes of edaravone-treated groups or nontreated groups after reoxygenation. Edaravone significantly attenuated the elevation of the AST level of the medium and hepatocellular PCOOH and preserved the hepatocellular ATP level. In vivo, male Sprague-Dawley rats were subjected to 45 minutes of hepatic ischemia and 120 minutes of reperfusion. The rats were intravenously injected with vehicle or edaravone (3 mg/kg or 10 mg/kg) before reperfusion and 1 hour after reperfusion. Serum AST levels and hepatic PCOOH and energy charge were significantly improved in both edaravone groups compared with control. In conclusion, edaravone has the ability to eliminate intra-hepatocellular superoxide species and attenuate oxidative liver damage in liver surgery.

Animals↗

PubMedDate not supplied

Hepatic resection through an anterior approach employing a modified liver hanging maneuver in patients with a massive liver tumor severely oppressing the inferior vena cava.

For a large hepatic neoplasm existing in the right hepatic lobe, hepatic resection using an anterior approach is required. We have reported an operative procedure for hepatic transection using absorbable polyglycolic acid tape. In patients with suspected tumor invasion of the inferior vena cava, on the other hand, considering the range of the residual tumor while sparing the inferior vena cava as much as possible, combined resection and reconstruction of the inferior vena cava is conducted only if operative curativity is expected. We conducted hepatic transection while maintaining the blood flow of the residual liver by applying the liver hanging maneuver method of Belghiti et al. and polyglycolic acid tape in patients with giant liver tumors of the right hepatic lobe compressing the hepatic inferior vena cava. Strong angled dissecting forceps were inserted into the ventral side of the inferior vena cava from the caudal side, and the tip was induced between hepatic veins. Two strips of polyglycolic acid tape were pinched with forceps and strongly ligated on the right and left sides of the cutoff line. Subsequently, hepatic transection was conducted using electrocautery spray coagulation and CUSA without blocking the inflow blood of the residual liver, and the right hepatic lobe was extirpated. This procedure has already been performed in 5 patients suspected of inferior vena cava invasion, and the inferior vena cava was able to be preserved in all the patients.

Carcinoma, Hepatocellular↗