Taichi Kanamaru

Expression profile of a γ-deletion variant of the human telomerase reverse transcriptase gene

The human telomerase reverse transcriptase (hTERT) is an essential component of the holoenzyme complex that adds telomeric repeats to the ends of chromosomes. The hTERT transcript has been shown to have two deletion type alternative splicing sites. One deletion site induces the alpha-deletion variant, lacking 36 bp from exon 6, and the other induces the beta-deletion variant, lacking 182 bp from exons 7 and 8. Here, we identified a novel deletion variant of the hTERT transcript in hepatocellular carcinoma cell lines. The deleted transcript was characterized by an in-frame deletion of 189 bp, spanning nucleotides 2710 to 2898, corresponding to the complete loss of exon 11 (gamma-deletion). The region lacking in the gamma-deletion lies within RT motifs D and E, suggesting that it is missing conserved residues from the catalytic core of the protein. Both gamma- and alpha-deletion variants were occasionally detected, but the beta-deletion variant was frequently observed. Our results may provide important information for more detailed studies on the regulation of telomerase activity.

Clinical significance of urokinase‐type plasminogen activator activity in hepatocellular carcinoma

Background and Methods : The plasminogen activation system plays a crucial role in the process of cancer invasion and metastasis. To evaluate the most effective factor in the invasion, metastasis and prognosis of hepatocellular carcinoma (HCC), we examined urokinase‐type plasminogen activator (uPA), plasminogen activator inhibitor (PAI)‐1, PAI‐2 and uPA activity by enzyme‐linked immunosorbent assays (ELISA) in HCC tissues obtained from 46 patients. The results were compared with the patients’ clinicopathological features and prognoses.

Telomerase activity in hepatocellular carcinoma as a predictor of postoperative recurrence

Telomerase is a ribonucleoprotein that stabilizes telomeres and allows unlimited cell division. It has been reported that most cancer cells evince reactivated telomerase. We examined telomerase activity in 29 patients with hepatocellular carcinoma (HCC) by a polymerase chain reaction-based semiquantitative assay. Of 24 HCCs, telomerase activity was positive in 23 (95,8%), of which 16 showed strong activity. In 11 well differentiated HCCs, telomerase activity was strong in 5, weak in 5, and undetected in 1 and in 13 moderately differentiated HCCs, it was strong in 11 and weak in 2. Five of 6 HCCs less than 2 cm in diameter expressed strong telomerase activity, while weak telomerase activity was detected in 7 of 19 (36.8%) resected noncancerous liver tissues from the HCC patients. Five of these 7 patients (71%) manifested recurrence within 6 months after surgery. The recurrence rate in these patients whose noncancerous liver tissue was positive for telomerase activity was significantly higher than that in patients in whom it was negative (P=0.017). These results suggest that the presence of telomerase activity may be a useful diagnostic marker of HCC, regardless of tumor size, and that its detection in resected noncancerous liver tissues may serve as a useful predictor of postoperative recurrence.

Inhibitory Role of Plasminogen Activator Inhibitor-1 in Invasion and Proliferation of HLE Hepatocellular Carcinoma Cells

Plasminogen activator inhibitor (PAI)‐1, a serine protease inhibitor, inactivates urokinase‐type plasminogen activator (uPA) and regulates degradation of the extracellular matrix; whether it functions for or against tumor progression, however, has been the subject of controversy. To assess the role of PAI‐1 in invasion and proliferation of hepatocellular carcinoma (HCC) cells, HLE cells were transfected with a vector capable of expressing an antisense PAI‐1 transcript. Analysis of seven stably transfected clones (PAI‐1−) showed reductions of 81% in PAI‐1 mRNA by northern blot analysis and 63% in the cellular PAI‐1 antigen level by enzyme‐linked immunosorbent assay(ELISA). There was no change in the levels of secreted PAI‐1 or PAI‐2. The activity of cellular uPA increased by 54%, without change in the protein level or the secreted uPA activity evaluated by ELISA. Morphologically, PAI‐1 antisense induced a spindle shape with narrower cytoplasmic processes in HLE cells. The forced inhibition of PAI‐1 increased the invasion and the growth of PAI‐1− cells by 75% and 82%, respectively. These results suggest that PAI‐1 plays a role in inhibiting invasion and proliferation, and the balance between uPA and PAI‐1 expression is important to assess the invasiveness of HCC cells.

Laparoscopic choledochotomy in management of choledocholithiasis.

Purpose Laparoscopic choledochotomy on patients indicated for common bile duct exploration was carried out according to an algorithm for managing choledocholithiasis. This study describes retrospectively our method and evaluates a new cystic duct biliary decompression cannula (J-tube) as an alternative to the T-tube. Methods Patients with confirmed choledocholithiasis (n=46) underwent laparoscopic choledochotomy. The T-tube was inserted in cases with suspected retained stones after common bile duct clearance, and the J-tube (950-mm long, 4 Fr) with a tapered and J-shaped segment at the distal end was inserted in other cases. Results Only 1 case was converted to open surgery (success rate, 97.8%); the J-tube was inserted in 30 patients and the T-tube in 15. The median operation time, hospital stay, and the interval until removal of the tube were significantly shorter with J-tube than with T-tube cases. Bile leakage after surgery occurred in 4 J-tube and 2 T-tube cases with one residual stone in each case. Conclusions The transcystic decompression tube is easily and safely inserted with the J-kit. Among several strategies currently available for the management of choledocholithiasis, laparoscopic choledochotomy with the use of the J-tube is one of the safest and most feasible methods.

Resected acinar cell carcinoma of the pancreas with tumor thrombus extending into the main portal vein: Report of a case

The incidence of acinar cell carcinoma has been reported to be about 1% of all pancreatic neoplasms, and pancreatic cancer combined with tumor growth extending into the portal vein is a rare condition. We herein report a case of acinar cell carcinoma of the pancreas with a tumor thrombus extending into the main portal trunk. Preoperative imaging of the portal vein, consisting of computed tomography (CT), magnetic resonance imaging (MRI), and angiography, revealed an oval shadow defect in the main portal trunk along with an irregular mass in the pancreatic head. At operation, we confirmed a tumor thrombus extending from a tumor in the pancreatic head into the main portal trunk via the pancreatoduodenal veins. A pancreatoduodenectomy combined with partial resection of the portal vein was thus performed under a temporary portal vein shunt from the ileocecal vein to the umbilical vein. Immunohistochemical examination for α1-antichimotrypsin and electron microscopic examination confirmed the diagnosis of acinar cell carcinoma of the pancreas with a tumor thrombus in the portal vein. Surgical excision combined with portal vein resection may therefore improve the prognosis of selected patients with portal tumor thrombus.

The effect of a nucleotide-nucleoside solution on hepatic regeneration after partial hepatectomy in rats

After hepatectomy, purine and pyrimidine metabolism is a key process in the synthesis of DNA and RNA and maintaining cellular energy metabolism. The purpose of this study is to evaluate changes in blood purine and pyrimidine levels after partial hepatectomy and the effect of purine and pyrimidine nucleoside solution injection on hepatic regeneration under the hypothesis that the rat after partial hepatectomy requires substrates for salvage nucleotide synthesis and changes blood nucleoside and nucleobase levels. Blood levels of nucleotides, nucleosides, and nucleobase by high-performance liquid chromatography method and liver ATP level by enzymatic analysis, and the effect of preoperative injection of nucleoside solution (OG-VI) on hepatic regeneration ratio and hepatocytes DNA synthesis, were assessed in rats after 70% partial hepatectomy. Decreased liver adenosine triphosphate and increased plasma xanthine and hypoxanthine after partial hepatectomy indicated an increase in catabolism of purine nucleotides in regenerating liver. Plasma thymidine and cytidine levels increased, then returned to the prevalue, suggesting that the thymidine and cytidine pool was enlarged. OG-VI increased labeling indices of hepatocytes at postoperative d 1 (POD) and hepatic regeneration ratio at POD 14. Blood purine nucleobase and pyrimidine nucleoside levels change after partial hepatectomy and preoperative supply of nucleoside solution is effective for increasing hepatocytes DNA synthesis and hepatic regeneration after partial hepatectomy.

Effect of a parenteral nucleoside-nucleotide mixture on hepatic metabolism in partially hepatectomized cirrhotic rats

After hepatectomy, purine and pyrimidine metabolism is a key process in synthesis of DNA and RNA and in energy metabolism. To supply nucleosides for salvage synthesis, nucleoside-nucleotide mixture solutions have been developed, and they have been found to improve protein metabolism and hepatic regeneration after partial hepatectomy in normal rats. However, the effect of the solution in cirrhotic liver, common in patients with hepatocellular carcinoma, has not been reported. The aim of this study was to evaluate the metabolic effect of the nucleoside-nucleotide mixture on cirrhotic rats after partial hepatectomy. Seventy percent partial hepatectomy was performed in thioacetamide-administered cirrhotic rats. The fractional protein synthetic rate, nitrogen balance, hepatic content of nucleic acid, and blood chemistry after the administration of the nucleoside-nucleotide mixture solution (OG-VI) with total parenteral nutrition was evaluated at 7 d after partial hepatectomy. OG-VI increased hepatic RNA level and hepatic fractional protein synthetic rate (p < 0.05). It is concluded that the nucleoside-nucleotide mixture solution is an effective nutritional supplement to the metabolism of cirrhotic rats after partial hepatectomy.

Assessment of Quality of Life After Pancreatoduodenectomy

The quality of life (QOL) after pancreatoduodenectomy (PD) was assessed by symptom scale scores related to physical and emotional aspects, performance status (PS) as social activity, and the Cornell Medical Index (CMI), related to psychophysiological aspects. Complete sets of data were obtained from 33 patients. A follow-up period after PD varied from 1 to 16 years. The incidence of the emotional symptoms was relatively higher than the physical symptoms. The symptom scale scores showed highest correlations with PS and CMI. Problems in the psychological condition might be related to significant differences in QOL. It is necessary to make a long-term evaluation for postoperative cholangitis, for which alkaline phosphatase levels in the blood and biliary scintigraphy are useful for diagnosis even in a symptom-free period.

The Effect of Dietary Nucleic Acid Deficiency and the Administration of a Nucleotide and Nucleosides Mixture Solution on Endotoxin Shock in Rats

The importance of dietary nucleic acid in modulation of immune function without disease has been reported in nutritional disorder except under surgical stress. Dietary nucleic acid deficiency decreases T lymphocytes function1 and dietary ribonucleic acid (RNA) enhances immune response2. However, it is not known whether dietary nucleic acid influences on macrophage function. Recently, monocytes/macrophages are considered as key factors in the pathogenesis of systemic inflammatory response leading to septic shock by producing humoral mediators under endotoxin stimulation3, 4. Therefore, the aim of this study is to evaluate the influence of dietary nucleic acid deficiency on endotoxin shock and macrophage functions stimulated with lipopolysaccharide (LPS), which is the major component of endotoxin. Then, the effect of intraperitoneal administration of a nucleotide and nucleosides mixture solution (OG-VI)5 was evaluated.